wasCSharpSQLite – Rev 1
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using System;
using System.Diagnostics;
using System.Text;
using i64 = System.Int64;
using u8 = System.Byte;
using u16 = System.UInt16;
using u32 = System.UInt32;
using u64 = System.UInt64;
using sqlite3_int64 = System.Int64;
using Pgno = System.UInt32;
namespace Community.CsharpSqlite
{
using DbPage = Sqlite3.PgHdr;
public partial class Sqlite3
{
/*
** 2004 April 6
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*************************************************************************
** Included in SQLite3 port to C#-SQLite; 2008 Noah B Hart
** C#-SQLite is an independent reimplementation of the SQLite software library
**
** SQLITE_SOURCE_ID: 2011-06-23 19:49:22 4374b7e83ea0a3fbc3691f9c0c936272862f32f2
**
*************************************************************************
*/
//#include "btreeInt.h"
/*
** The header string that appears at the beginning of every
** SQLite database.
*/
static byte[] zMagicHeader = Encoding.UTF8.GetBytes( SQLITE_FILE_HEADER );
/*
** Set this global variable to 1 to enable tracing using the TRACE
** macro.
*/
#if TRACE
static bool sqlite3BtreeTrace=false; /* True to enable tracing */
//# define TRACE(X) if(sqlite3BtreeTrace){printf X;fflush(stdout);}
static void TRACE(string X, params object[] ap) { if (sqlite3BtreeTrace) printf(X, ap); }
#else
//# define TRACE(X)
static void TRACE( string X, params object[] ap )
{
}
#endif
/*
** Extract a 2-byte big-endian integer from an array of unsigned bytes.
** But if the value is zero, make it 65536.
**
** This routine is used to extract the "offset to cell content area" value
** from the header of a btree page. If the page size is 65536 and the page
** is empty, the offset should be 65536, but the 2-byte value stores zero.
** This routine makes the necessary adjustment to 65536.
*/
//#define get2byteNotZero(X) (((((int)get2byte(X))-1)&0xffff)+1)
static int get2byteNotZero( byte[] X, int offset )
{
return ( ( ( ( (int)get2byte( X, offset ) ) - 1 ) & 0xffff ) + 1 );
}
#if !SQLITE_OMIT_SHARED_CACHE
/*
** A list of BtShared objects that are eligible for participation
** in shared cache. This variable has file scope during normal builds,
** but the test harness needs to access it so we make it global for
** test builds.
**
** Access to this variable is protected by SQLITE_MUTEX_STATIC_MASTER.
*/
#if SQLITE_TEST
BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
#else
static BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
#endif
#endif //* SQLITE_OMIT_SHARED_CACHE */
#if !SQLITE_OMIT_SHARED_CACHE
/*
** Enable or disable the shared pager and schema features.
**
** This routine has no effect on existing database connections.
** The shared cache setting effects only future calls to
** sqlite3_open(), sqlite3_open16(), or sqlite3_open_v2().
*/
int sqlite3_enable_shared_cache(int enable){
sqlite3GlobalConfig.sharedCacheEnabled = enable;
return SQLITE_OK;
}
#endif
#if SQLITE_OMIT_SHARED_CACHE
/*
** The functions querySharedCacheTableLock(), setSharedCacheTableLock(),
** and clearAllSharedCacheTableLocks()
** manipulate entries in the BtShared.pLock linked list used to store
** shared-cache table level locks. If the library is compiled with the
** shared-cache feature disabled, then there is only ever one user
** of each BtShared structure and so this locking is not necessary.
** So define the lock related functions as no-ops.
*/
//#define querySharedCacheTableLock(a,b,c) SQLITE_OK
static int querySharedCacheTableLock( Btree p, Pgno iTab, u8 eLock )
{
return SQLITE_OK;
}
//#define setSharedCacheTableLock(a,b,c) SQLITE_OK
//#define clearAllSharedCacheTableLocks(a)
static void clearAllSharedCacheTableLocks( Btree a )
{
}
//#define downgradeAllSharedCacheTableLocks(a)
static void downgradeAllSharedCacheTableLocks( Btree a )
{
}
//#define hasSharedCacheTableLock(a,b,c,d) 1
static bool hasSharedCacheTableLock( Btree a, Pgno b, int c, int d )
{
return true;
}
//#define hasReadConflicts(a, b) 0
static bool hasReadConflicts( Btree a, Pgno b )
{
return false;
}
#endif
#if !SQLITE_OMIT_SHARED_CACHE
#if SQLITE_DEBUG
/*
**** This function is only used as part of an assert() statement. ***
**
** Check to see if pBtree holds the required locks to read or write to the
** table with root page iRoot. Return 1 if it does and 0 if not.
**
** For example, when writing to a table with root-page iRoot via
** Btree connection pBtree:
**
** assert( hasSharedCacheTableLock(pBtree, iRoot, 0, WRITE_LOCK) );
**
** When writing to an index that resides in a sharable database, the
** caller should have first obtained a lock specifying the root page of
** the corresponding table. This makes things a bit more complicated,
** as this module treats each table as a separate structure. To determine
** the table corresponding to the index being written, this
** function has to search through the database schema.
**
** Instead of a lock on the table/index rooted at page iRoot, the caller may
** hold a write-lock on the schema table (root page 1). This is also
** acceptable.
*/
static int hasSharedCacheTableLock(
Btree pBtree, /* Handle that must hold lock */
Pgno iRoot, /* Root page of b-tree */
int isIndex, /* True if iRoot is the root of an index b-tree */
int eLockType /* Required lock type (READ_LOCK or WRITE_LOCK) */
){
Schema pSchema = (Schema *)pBtree.pBt.pSchema;
Pgno iTab = 0;
BtLock pLock;
/* If this database is not shareable, or if the client is reading
** and has the read-uncommitted flag set, then no lock is required.
** Return true immediately.
*/
if( (pBtree.sharable==null)
|| (eLockType==READ_LOCK && (pBtree.db.flags & SQLITE_ReadUncommitted))
){
return 1;
}
/* If the client is reading or writing an index and the schema is
** not loaded, then it is too difficult to actually check to see if
** the correct locks are held. So do not bother - just return true.
** This case does not come up very often anyhow.
*/
if( isIndex && (!pSchema || (pSchema->flags&DB_SchemaLoaded)==0) ){
return 1;
}
/* Figure out the root-page that the lock should be held on. For table
** b-trees, this is just the root page of the b-tree being read or
** written. For index b-trees, it is the root page of the associated
** table. */
if( isIndex ){
HashElem p;
for(p=sqliteHashFirst(pSchema.idxHash); p!=null; p=sqliteHashNext(p)){
Index pIdx = (Index *)sqliteHashData(p);
if( pIdx.tnum==(int)iRoot ){
iTab = pIdx.pTable.tnum;
}
}
}else{
iTab = iRoot;
}
/* Search for the required lock. Either a write-lock on root-page iTab, a
** write-lock on the schema table, or (if the client is reading) a
** read-lock on iTab will suffice. Return 1 if any of these are found. */
for(pLock=pBtree.pBt.pLock; pLock; pLock=pLock.pNext){
if( pLock.pBtree==pBtree
&& (pLock.iTable==iTab || (pLock.eLock==WRITE_LOCK && pLock.iTable==1))
&& pLock.eLock>=eLockType
){
return 1;
}
}
/* Failed to find the required lock. */
return 0;
}
#endif //* SQLITE_DEBUG */
#if SQLITE_DEBUG
/*
** This function may be used as part of assert() statements only. ****
**
** Return true if it would be illegal for pBtree to write into the
** table or index rooted at iRoot because other shared connections are
** simultaneously reading that same table or index.
**
** It is illegal for pBtree to write if some other Btree object that
** shares the same BtShared object is currently reading or writing
** the iRoot table. Except, if the other Btree object has the
** read-uncommitted flag set, then it is OK for the other object to
** have a read cursor.
**
** For example, before writing to any part of the table or index
** rooted at page iRoot, one should call:
**
** assert( !hasReadConflicts(pBtree, iRoot) );
*/
static int hasReadConflicts(Btree pBtree, Pgno iRoot){
BtCursor p;
for(p=pBtree.pBt.pCursor; p!=null; p=p.pNext){
if( p.pgnoRoot==iRoot
&& p.pBtree!=pBtree
&& 0==(p.pBtree.db.flags & SQLITE_ReadUncommitted)
){
return 1;
}
}
return 0;
}
#endif //* #if SQLITE_DEBUG */
/*
** Query to see if Btree handle p may obtain a lock of type eLock
** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
** SQLITE_OK if the lock may be obtained (by calling
** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
*/
static int querySharedCacheTableLock(Btree p, Pgno iTab, u8 eLock){
BtShared pBt = p.pBt;
BtLock pIter;
Debug.Assert( sqlite3BtreeHoldsMutex(p) );
Debug.Assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
Debug.Assert( p.db!=null );
Debug.Assert( !(p.db.flags&SQLITE_ReadUncommitted)||eLock==WRITE_LOCK||iTab==1 );
/* If requesting a write-lock, then the Btree must have an open write
** transaction on this file. And, obviously, for this to be so there
** must be an open write transaction on the file itself.
*/
Debug.Assert( eLock==READ_LOCK || (p==pBt.pWriter && p.inTrans==TRANS_WRITE) );
Debug.Assert( eLock==READ_LOCK || pBt.inTransaction==TRANS_WRITE );
/* This routine is a no-op if the shared-cache is not enabled */
if( !p.sharable ){
return SQLITE_OK;
}
/* If some other connection is holding an exclusive lock, the
** requested lock may not be obtained.
*/
if( pBt.pWriter!=p && pBt.isExclusive ){
sqlite3ConnectionBlocked(p.db, pBt.pWriter.db);
return SQLITE_LOCKED_SHAREDCACHE;
}
for(pIter=pBt.pLock; pIter; pIter=pIter.pNext){
/* The condition (pIter.eLock!=eLock) in the following if(...)
** statement is a simplification of:
**
** (eLock==WRITE_LOCK || pIter.eLock==WRITE_LOCK)
**
** since we know that if eLock==WRITE_LOCK, then no other connection
** may hold a WRITE_LOCK on any table in this file (since there can
** only be a single writer).
*/
Debug.Assert( pIter.eLock==READ_LOCK || pIter.eLock==WRITE_LOCK );
Debug.Assert( eLock==READ_LOCK || pIter.pBtree==p || pIter.eLock==READ_LOCK);
if( pIter.pBtree!=p && pIter.iTable==iTab && pIter.eLock!=eLock ){
sqlite3ConnectionBlocked(p.db, pIter.pBtree.db);
if( eLock==WRITE_LOCK ){
Debug.Assert( p==pBt.pWriter );
pBt.isPending = 1;
}
return SQLITE_LOCKED_SHAREDCACHE;
}
}
return SQLITE_OK;
}
#endif //* !SQLITE_OMIT_SHARED_CACHE */
#if !SQLITE_OMIT_SHARED_CACHE
/*
** Add a lock on the table with root-page iTable to the shared-btree used
** by Btree handle p. Parameter eLock must be either READ_LOCK or
** WRITE_LOCK.
**
** This function assumes the following:
**
** (a) The specified Btree object p is connected to a sharable
** database (one with the BtShared.sharable flag set), and
**
** (b) No other Btree objects hold a lock that conflicts
** with the requested lock (i.e. querySharedCacheTableLock() has
** already been called and returned SQLITE_OK).
**
** SQLITE_OK is returned if the lock is added successfully. SQLITE_NOMEM
** is returned if a malloc attempt fails.
*/
static int setSharedCacheTableLock(Btree p, Pgno iTable, u8 eLock){
BtShared pBt = p.pBt;
BtLock pLock = 0;
BtLock pIter;
Debug.Assert( sqlite3BtreeHoldsMutex(p) );
Debug.Assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
Debug.Assert( p.db!=null );
/* A connection with the read-uncommitted flag set will never try to
** obtain a read-lock using this function. The only read-lock obtained
** by a connection in read-uncommitted mode is on the sqlite_master
** table, and that lock is obtained in BtreeBeginTrans(). */
Debug.Assert( 0==(p.db.flags&SQLITE_ReadUncommitted) || eLock==WRITE_LOCK );
/* This function should only be called on a sharable b-tree after it
** has been determined that no other b-tree holds a conflicting lock. */
Debug.Assert( p.sharable );
Debug.Assert( SQLITE_OK==querySharedCacheTableLock(p, iTable, eLock) );
/* First search the list for an existing lock on this table. */
for(pIter=pBt.pLock; pIter; pIter=pIter.pNext){
if( pIter.iTable==iTable && pIter.pBtree==p ){
pLock = pIter;
break;
}
}
/* If the above search did not find a BtLock struct associating Btree p
** with table iTable, allocate one and link it into the list.
*/
if( !pLock ){
pLock = (BtLock *)sqlite3MallocZero(sizeof(BtLock));
if( !pLock ){
return SQLITE_NOMEM;
}
pLock.iTable = iTable;
pLock.pBtree = p;
pLock.pNext = pBt.pLock;
pBt.pLock = pLock;
}
/* Set the BtLock.eLock variable to the maximum of the current lock
** and the requested lock. This means if a write-lock was already held
** and a read-lock requested, we don't incorrectly downgrade the lock.
*/
Debug.Assert( WRITE_LOCK>READ_LOCK );
if( eLock>pLock.eLock ){
pLock.eLock = eLock;
}
return SQLITE_OK;
}
#endif //* !SQLITE_OMIT_SHARED_CACHE */
#if !SQLITE_OMIT_SHARED_CACHE
/*
** Release all the table locks (locks obtained via calls to
** the setSharedCacheTableLock() procedure) held by Btree object p.
**
** This function assumes that Btree p has an open read or write
** transaction. If it does not, then the BtShared.isPending variable
** may be incorrectly cleared.
*/
static void clearAllSharedCacheTableLocks(Btree p){
BtShared pBt = p.pBt;
BtLock **ppIter = &pBt.pLock;
Debug.Assert( sqlite3BtreeHoldsMutex(p) );
Debug.Assert( p.sharable || 0==*ppIter );
Debug.Assert( p.inTrans>0 );
while( ppIter ){
BtLock pLock = ppIter;
Debug.Assert( pBt.isExclusive==null || pBt.pWriter==pLock.pBtree );
Debug.Assert( pLock.pBtree.inTrans>=pLock.eLock );
if( pLock.pBtree==p ){
ppIter = pLock.pNext;
Debug.Assert( pLock.iTable!=1 || pLock==&p.lock );
if( pLock.iTable!=1 ){
pLock=null;//sqlite3_free(ref pLock);
}
}else{
ppIter = &pLock.pNext;
}
}
Debug.Assert( pBt.isPending==null || pBt.pWriter );
if( pBt.pWriter==p ){
pBt.pWriter = 0;
pBt.isExclusive = 0;
pBt.isPending = 0;
}else if( pBt.nTransaction==2 ){
/* This function is called when Btree p is concluding its
** transaction. If there currently exists a writer, and p is not
** that writer, then the number of locks held by connections other
** than the writer must be about to drop to zero. In this case
** set the isPending flag to 0.
**
** If there is not currently a writer, then BtShared.isPending must
** be zero already. So this next line is harmless in that case.
*/
pBt.isPending = 0;
}
}
/*
** This function changes all write-locks held by Btree p into read-locks.
*/
static void downgradeAllSharedCacheTableLocks(Btree p){
BtShared pBt = p.pBt;
if( pBt.pWriter==p ){
BtLock pLock;
pBt.pWriter = 0;
pBt.isExclusive = 0;
pBt.isPending = 0;
for(pLock=pBt.pLock; pLock; pLock=pLock.pNext){
Debug.Assert( pLock.eLock==READ_LOCK || pLock.pBtree==p );
pLock.eLock = READ_LOCK;
}
}
}
#endif //* SQLITE_OMIT_SHARED_CACHE */
//static void releasePage(MemPage pPage); /* Forward reference */
/*
***** This routine is used inside of assert() only ****
**
** Verify that the cursor holds the mutex on its BtShared
*/
#if SQLITE_DEBUG
static bool cursorHoldsMutex( BtCursor p )
{
return sqlite3_mutex_held( p.pBt.mutex );
}
#else
static bool cursorHoldsMutex(BtCursor p) { return true; }
#endif
#if !SQLITE_OMIT_INCRBLOB
/*
** Invalidate the overflow page-list cache for cursor pCur, if any.
*/
static void invalidateOverflowCache(BtCursor pCur){
Debug.Assert( cursorHoldsMutex(pCur) );
//sqlite3_free(ref pCur.aOverflow);
pCur.aOverflow = null;
}
/*
** Invalidate the overflow page-list cache for all cursors opened
** on the shared btree structure pBt.
*/
static void invalidateAllOverflowCache(BtShared pBt){
BtCursor p;
Debug.Assert( sqlite3_mutex_held(pBt.mutex) );
for(p=pBt.pCursor; p!=null; p=p.pNext){
invalidateOverflowCache(p);
}
}
/*
** This function is called before modifying the contents of a table
** to invalidate any incrblob cursors that are open on the
** row or one of the rows being modified.
**
** If argument isClearTable is true, then the entire contents of the
** table is about to be deleted. In this case invalidate all incrblob
** cursors open on any row within the table with root-page pgnoRoot.
**
** Otherwise, if argument isClearTable is false, then the row with
** rowid iRow is being replaced or deleted. In this case invalidate
** only those incrblob cursors open on that specific row.
*/
static void invalidateIncrblobCursors(
Btree pBtree, /* The database file to check */
i64 iRow, /* The rowid that might be changing */
int isClearTable /* True if all rows are being deleted */
){
BtCursor p;
BtShared pBt = pBtree.pBt;
Debug.Assert( sqlite3BtreeHoldsMutex(pBtree) );
for(p=pBt.pCursor; p!=null; p=p.pNext){
if( p.isIncrblobHandle && (isClearTable || p.info.nKey==iRow) ){
p.eState = CURSOR_INVALID;
}
}
}
#else
/* Stub functions when INCRBLOB is omitted */
//#define invalidateOverflowCache(x)
static void invalidateOverflowCache( BtCursor pCur )
{
}
//#define invalidateAllOverflowCache(x)
static void invalidateAllOverflowCache( BtShared pBt )
{
}
//#define invalidateIncrblobCursors(x,y,z)
static void invalidateIncrblobCursors( Btree x, i64 y, int z )
{
}
#endif //* SQLITE_OMIT_INCRBLOB */
/*
** Set bit pgno of the BtShared.pHasContent bitvec. This is called
** when a page that previously contained data becomes a free-list leaf
** page.
**
** The BtShared.pHasContent bitvec exists to work around an obscure
** bug caused by the interaction of two useful IO optimizations surrounding
** free-list leaf pages:
**
** 1) When all data is deleted from a page and the page becomes
** a free-list leaf page, the page is not written to the database
** (as free-list leaf pages contain no meaningful data). Sometimes
** such a page is not even journalled (as it will not be modified,
** why bother journalling it?).
**
** 2) When a free-list leaf page is reused, its content is not read
** from the database or written to the journal file (why should it
** be, if it is not at all meaningful?).
**
** By themselves, these optimizations work fine and provide a handy
** performance boost to bulk delete or insert operations. However, if
** a page is moved to the free-list and then reused within the same
** transaction, a problem comes up. If the page is not journalled when
** it is moved to the free-list and it is also not journalled when it
** is extracted from the free-list and reused, then the original data
** may be lost. In the event of a rollback, it may not be possible
** to restore the database to its original configuration.
**
** The solution is the BtShared.pHasContent bitvec. Whenever a page is
** moved to become a free-list leaf page, the corresponding bit is
** set in the bitvec. Whenever a leaf page is extracted from the free-list,
** optimization 2 above is omitted if the corresponding bit is already
** set in BtShared.pHasContent. The contents of the bitvec are cleared
** at the end of every transaction.
*/
static int btreeSetHasContent( BtShared pBt, Pgno pgno )
{
int rc = SQLITE_OK;
if ( null == pBt.pHasContent )
{
Debug.Assert( pgno <= pBt.nPage );
pBt.pHasContent = sqlite3BitvecCreate( pBt.nPage );
//if ( null == pBt.pHasContent )
//{
// rc = SQLITE_NOMEM;
//}
}
if ( rc == SQLITE_OK && pgno <= sqlite3BitvecSize( pBt.pHasContent ) )
{
rc = sqlite3BitvecSet( pBt.pHasContent, pgno );
}
return rc;
}
/*
** Query the BtShared.pHasContent vector.
**
** This function is called when a free-list leaf page is removed from the
** free-list for reuse. It returns false if it is safe to retrieve the
** page from the pager layer with the 'no-content' flag set. True otherwise.
*/
static bool btreeGetHasContent( BtShared pBt, Pgno pgno )
{
Bitvec p = pBt.pHasContent;
return ( p != null && ( pgno > sqlite3BitvecSize( p ) || sqlite3BitvecTest( p, pgno ) != 0 ) );
}
/*
** Clear (destroy) the BtShared.pHasContent bitvec. This should be
** invoked at the conclusion of each write-transaction.
*/
static void btreeClearHasContent( BtShared pBt )
{
sqlite3BitvecDestroy( ref pBt.pHasContent );
pBt.pHasContent = null;
}
/*
** Save the current cursor position in the variables BtCursor.nKey
** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
**
** The caller must ensure that the cursor is valid (has eState==CURSOR_VALID)
** prior to calling this routine.
*/
static int saveCursorPosition( BtCursor pCur )
{
int rc;
Debug.Assert( CURSOR_VALID == pCur.eState );
Debug.Assert( null == pCur.pKey );
Debug.Assert( cursorHoldsMutex( pCur ) );
rc = sqlite3BtreeKeySize( pCur, ref pCur.nKey );
Debug.Assert( rc == SQLITE_OK ); /* KeySize() cannot fail */
/* If this is an intKey table, then the above call to BtreeKeySize()
** stores the integer key in pCur.nKey. In this case this value is
** all that is required. Otherwise, if pCur is not open on an intKey
** table, then malloc space for and store the pCur.nKey bytes of key
** data.
*/
if ( 0 == pCur.apPage[0].intKey )
{
byte[] pKey = sqlite3Malloc( (int)pCur.nKey );
//if( pKey !=null){
rc = sqlite3BtreeKey( pCur, 0, (u32)pCur.nKey, pKey );
if ( rc == SQLITE_OK )
{
pCur.pKey = pKey;
}
//else{
// sqlite3_free(ref pKey);
//}
//}else{
// rc = SQLITE_NOMEM;
//}
}
Debug.Assert( 0 == pCur.apPage[0].intKey || null == pCur.pKey );
if ( rc == SQLITE_OK )
{
int i;
for ( i = 0; i <= pCur.iPage; i++ )
{
releasePage( pCur.apPage[i] );
pCur.apPage[i] = null;
}
pCur.iPage = -1;
pCur.eState = CURSOR_REQUIRESEEK;
}
invalidateOverflowCache( pCur );
return rc;
}
/*
** Save the positions of all cursors (except pExcept) that are open on
** the table with root-page iRoot. Usually, this is called just before cursor
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
*/
static int saveAllCursors( BtShared pBt, Pgno iRoot, BtCursor pExcept )
{
BtCursor p;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( pExcept == null || pExcept.pBt == pBt );
for ( p = pBt.pCursor; p != null; p = p.pNext )
{
if ( p != pExcept && ( 0 == iRoot || p.pgnoRoot == iRoot ) &&
p.eState == CURSOR_VALID )
{
int rc = saveCursorPosition( p );
if ( SQLITE_OK != rc )
{
return rc;
}
}
}
return SQLITE_OK;
}
/*
** Clear the current cursor position.
*/
static void sqlite3BtreeClearCursor( BtCursor pCur )
{
Debug.Assert( cursorHoldsMutex( pCur ) );
sqlite3_free( ref pCur.pKey );
pCur.eState = CURSOR_INVALID;
}
/*
** In this version of BtreeMoveto, pKey is a packed index record
** such as is generated by the OP_MakeRecord opcode. Unpack the
** record and then call BtreeMovetoUnpacked() to do the work.
*/
static int btreeMoveto(
BtCursor pCur, /* Cursor open on the btree to be searched */
byte[] pKey, /* Packed key if the btree is an index */
i64 nKey, /* Integer key for tables. Size of pKey for indices */
int bias, /* Bias search to the high end */
ref int pRes /* Write search results here */
)
{
int rc; /* Status code */
UnpackedRecord pIdxKey; /* Unpacked index key */
UnpackedRecord aSpace = new UnpackedRecord();//char aSpace[150]; /* Temp space for pIdxKey - to avoid a malloc */
if ( pKey != null )
{
Debug.Assert( nKey == (i64)(int)nKey );
pIdxKey = sqlite3VdbeRecordUnpack( pCur.pKeyInfo, (int)nKey, pKey,
aSpace, 16 );//sizeof( aSpace ) );
//if ( pIdxKey == null )
// return SQLITE_NOMEM;
}
else
{
pIdxKey = null;
}
rc = sqlite3BtreeMovetoUnpacked( pCur, pIdxKey, nKey, bias != 0 ? 1 : 0, ref pRes );
if ( pKey != null )
{
sqlite3VdbeDeleteUnpackedRecord( pIdxKey );
}
return rc;
}
/*
** Restore the cursor to the position it was in (or as close to as possible)
** when saveCursorPosition() was called. Note that this call deletes the
** saved position info stored by saveCursorPosition(), so there can be
** at most one effective restoreCursorPosition() call after each
** saveCursorPosition().
*/
static int btreeRestoreCursorPosition( BtCursor pCur )
{
int rc;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState >= CURSOR_REQUIRESEEK );
if ( pCur.eState == CURSOR_FAULT )
{
return pCur.skipNext;
}
pCur.eState = CURSOR_INVALID;
rc = btreeMoveto( pCur, pCur.pKey, pCur.nKey, 0, ref pCur.skipNext );
if ( rc == SQLITE_OK )
{
//sqlite3_free(ref pCur.pKey);
pCur.pKey = null;
Debug.Assert( pCur.eState == CURSOR_VALID || pCur.eState == CURSOR_INVALID );
}
return rc;
}
//#define restoreCursorPosition(p) \
// (p.eState>=CURSOR_REQUIRESEEK ? \
// btreeRestoreCursorPosition(p) : \
// SQLITE_OK)
static int restoreCursorPosition( BtCursor pCur )
{
if ( pCur.eState >= CURSOR_REQUIRESEEK )
return btreeRestoreCursorPosition( pCur );
else
return SQLITE_OK;
}
/*
** Determine whether or not a cursor has moved from the position it
** was last placed at. Cursors can move when the row they are pointing
** at is deleted out from under them.
**
** This routine returns an error code if something goes wrong. The
** integer pHasMoved is set to one if the cursor has moved and 0 if not.
*/
static int sqlite3BtreeCursorHasMoved( BtCursor pCur, ref int pHasMoved )
{
int rc;
rc = restoreCursorPosition( pCur );
if ( rc != 0 )
{
pHasMoved = 1;
return rc;
}
if ( pCur.eState != CURSOR_VALID || pCur.skipNext != 0 )
{
pHasMoved = 1;
}
else
{
pHasMoved = 0;
}
return SQLITE_OK;
}
#if !SQLITE_OMIT_AUTOVACUUM
/*
** Given a page number of a regular database page, return the page
** number for the pointer-map page that contains the entry for the
** input page number.
**
** Return 0 (not a valid page) for pgno==1 since there is
** no pointer map associated with page 1. The integrity_check logic
** requires that ptrmapPageno(*,1)!=1.
*/
static Pgno ptrmapPageno( BtShared pBt, Pgno pgno )
{
int nPagesPerMapPage;
Pgno iPtrMap, ret;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
if ( pgno < 2 )
return 0;
nPagesPerMapPage = (int)( pBt.usableSize / 5 + 1 );
iPtrMap = (Pgno)( ( pgno - 2 ) / nPagesPerMapPage );
ret = (Pgno)( iPtrMap * nPagesPerMapPage ) + 2;
if ( ret == PENDING_BYTE_PAGE( pBt ) )
{
ret++;
}
return ret;
}
/*
** Write an entry into the pointer map.
**
** This routine updates the pointer map entry for page number 'key'
** so that it maps to type 'eType' and parent page number 'pgno'.
**
** If pRC is initially non-zero (non-SQLITE_OK) then this routine is
** a no-op. If an error occurs, the appropriate error code is written
** into pRC.
*/
static void ptrmapPut( BtShared pBt, Pgno key, u8 eType, Pgno parent, ref int pRC )
{
PgHdr pDbPage = new PgHdr(); /* The pointer map page */
u8[] pPtrmap; /* The pointer map data */
Pgno iPtrmap; /* The pointer map page number */
int offset; /* Offset in pointer map page */
int rc; /* Return code from subfunctions */
if ( pRC != 0 )
return;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
/* The master-journal page number must never be used as a pointer map page */
Debug.Assert( false == PTRMAP_ISPAGE( pBt, PENDING_BYTE_PAGE( pBt ) ) );
Debug.Assert( pBt.autoVacuum );
if ( key == 0 )
{
pRC = SQLITE_CORRUPT_BKPT();
return;
}
iPtrmap = PTRMAP_PAGENO( pBt, key );
rc = sqlite3PagerGet( pBt.pPager, iPtrmap, ref pDbPage );
if ( rc != SQLITE_OK )
{
pRC = rc;
return;
}
offset = (int)PTRMAP_PTROFFSET( iPtrmap, key );
if ( offset < 0 )
{
pRC = SQLITE_CORRUPT_BKPT();
goto ptrmap_exit;
}
Debug.Assert( offset <= (int)pBt.usableSize - 5 );
pPtrmap = sqlite3PagerGetData( pDbPage );
if ( eType != pPtrmap[offset] || sqlite3Get4byte( pPtrmap, offset + 1 ) != parent )
{
TRACE( "PTRMAP_UPDATE: %d->(%d,%d)\n", key, eType, parent );
pRC = rc = sqlite3PagerWrite( pDbPage );
if ( rc == SQLITE_OK )
{
pPtrmap[offset] = eType;
sqlite3Put4byte( pPtrmap, offset + 1, parent );
}
}
ptrmap_exit:
sqlite3PagerUnref( pDbPage );
}
/*
** Read an entry from the pointer map.
**
** This routine retrieves the pointer map entry for page 'key', writing
** the type and parent page number to pEType and pPgno respectively.
** An error code is returned if something goes wrong, otherwise SQLITE_OK.
*/
static int ptrmapGet( BtShared pBt, Pgno key, ref u8 pEType, ref Pgno pPgno )
{
PgHdr pDbPage = new PgHdr();/* The pointer map page */
int iPtrmap; /* Pointer map page index */
u8[] pPtrmap; /* Pointer map page data */
int offset; /* Offset of entry in pointer map */
int rc;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
iPtrmap = (int)PTRMAP_PAGENO( pBt, key );
rc = sqlite3PagerGet( pBt.pPager, (u32)iPtrmap, ref pDbPage );
if ( rc != 0 )
{
return rc;
}
pPtrmap = sqlite3PagerGetData( pDbPage );
offset = (int)PTRMAP_PTROFFSET( (u32)iPtrmap, key );
if ( offset < 0 )
{
sqlite3PagerUnref( pDbPage );
return SQLITE_CORRUPT_BKPT();
}
Debug.Assert( offset <= (int)pBt.usableSize - 5 );
// Under C# pEType will always exist. No need to test; //
//Debug.Assert( pEType != 0 );
pEType = pPtrmap[offset];
// Under C# pPgno will always exist. No need to test; //
//if ( pPgno != 0 )
pPgno = sqlite3Get4byte( pPtrmap, offset + 1 );
sqlite3PagerUnref( pDbPage );
if ( pEType < 1 || pEType > 5 )
return SQLITE_CORRUPT_BKPT();
return SQLITE_OK;
}
#else //* if defined SQLITE_OMIT_AUTOVACUUM */
//#define ptrmapPut(w,x,y,z,rc)
//#define ptrmapGet(w,x,y,z) SQLITE_OK
//#define ptrmapPutOvflPtr(x, y, rc)
#endif
/*
** Given a btree page and a cell index (0 means the first cell on
** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** This routine works only for pages that do not contain overflow cells.
*/
//#define findCell(P,I) \
// ((P).aData + ((P).maskPage & get2byte((P).aData[(P).cellOffset+2*(I)])))
static int findCell( MemPage pPage, int iCell )
{
return get2byte( pPage.aData, pPage.cellOffset + 2 * ( iCell ) );
}
//#define findCellv2(D,M,O,I) (D+(M&get2byte(D+(O+2*(I)))))
static u8[] findCellv2( u8[] pPage, u16 iCell, u16 O, int I )
{
Debugger.Break();
return pPage;
}
/*
** This a more complex version of findCell() that works for
** pages that do contain overflow cells.
*/
static int findOverflowCell( MemPage pPage, int iCell )
{
int i;
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
for ( i = pPage.nOverflow - 1; i >= 0; i-- )
{
int k;
_OvflCell pOvfl;
pOvfl = pPage.aOvfl[i];
k = pOvfl.idx;
if ( k <= iCell )
{
if ( k == iCell )
{
//return pOvfl.pCell;
return -i - 1; // Negative Offset means overflow cells
}
iCell--;
}
}
return findCell( pPage, iCell );
}
/*
** Parse a cell content block and fill in the CellInfo structure. There
** are two versions of this function. btreeParseCell() takes a
** cell index as the second argument and btreeParseCellPtr()
** takes a pointer to the body of the cell as its second argument.
**
** Within this file, the parseCell() macro can be called instead of
** btreeParseCellPtr(). Using some compilers, this will be faster.
*/
//OVERLOADS
static void btreeParseCellPtr(
MemPage pPage, /* Page containing the cell */
int iCell, /* Pointer to the cell text. */
ref CellInfo pInfo /* Fill in this structure */
)
{
btreeParseCellPtr( pPage, pPage.aData, iCell, ref pInfo );
}
static void btreeParseCellPtr(
MemPage pPage, /* Page containing the cell */
byte[] pCell, /* The actual data */
ref CellInfo pInfo /* Fill in this structure */
)
{
btreeParseCellPtr( pPage, pCell, 0, ref pInfo );
}
static void btreeParseCellPtr(
MemPage pPage, /* Page containing the cell */
u8[] pCell, /* Pointer to the cell text. */
int iCell, /* Pointer to the cell text. */
ref CellInfo pInfo /* Fill in this structure */
)
{
u16 n; /* Number bytes in cell content header */
u32 nPayload = 0; /* Number of bytes of cell payload */
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
if ( pInfo.pCell != pCell )
pInfo.pCell = pCell;
pInfo.iCell = iCell;
Debug.Assert( pPage.leaf == 0 || pPage.leaf == 1 );
n = pPage.childPtrSize;
Debug.Assert( n == 4 - 4 * pPage.leaf );
if ( pPage.intKey != 0 )
{
if ( pPage.hasData != 0 )
{
n += (u16)getVarint32( pCell, iCell + n, out nPayload );
}
else
{
nPayload = 0;
}
n += (u16)getVarint( pCell, iCell + n, out pInfo.nKey );
pInfo.nData = nPayload;
}
else
{
pInfo.nData = 0;
n += (u16)getVarint32( pCell, iCell + n, out nPayload );
pInfo.nKey = nPayload;
}
pInfo.nPayload = nPayload;
pInfo.nHeader = n;
testcase( nPayload == pPage.maxLocal );
testcase( nPayload == pPage.maxLocal + 1 );
if ( likely( nPayload <= pPage.maxLocal ) )
{
/* This is the (easy) common case where the entire payload fits
** on the local page. No overflow is required.
*/
if ( ( pInfo.nSize = (u16)( n + nPayload ) ) < 4 )
pInfo.nSize = 4;
pInfo.nLocal = (u16)nPayload;
pInfo.iOverflow = 0;
}
else
{
/* If the payload will not fit completely on the local page, we have
** to decide how much to store locally and how much to spill onto
** overflow pages. The strategy is to minimize the amount of unused
** space on overflow pages while keeping the amount of local storage
** in between minLocal and maxLocal.
**
** Warning: changing the way overflow payload is distributed in any
** way will result in an incompatible file format.
*/
int minLocal; /* Minimum amount of payload held locally */
int maxLocal; /* Maximum amount of payload held locally */
int surplus; /* Overflow payload available for local storage */
minLocal = pPage.minLocal;
maxLocal = pPage.maxLocal;
surplus = (int)( minLocal + ( nPayload - minLocal ) % ( pPage.pBt.usableSize - 4 ) );
testcase( surplus == maxLocal );
testcase( surplus == maxLocal + 1 );
if ( surplus <= maxLocal )
{
pInfo.nLocal = (u16)surplus;
}
else
{
pInfo.nLocal = (u16)minLocal;
}
pInfo.iOverflow = (u16)( pInfo.nLocal + n );
pInfo.nSize = (u16)( pInfo.iOverflow + 4 );
}
}
//#define parseCell(pPage, iCell, pInfo) \
// btreeParseCellPtr((pPage), findCell((pPage), (iCell)), (pInfo))
static void parseCell( MemPage pPage, int iCell, ref CellInfo pInfo )
{
btreeParseCellPtr( pPage, findCell( pPage, iCell ), ref pInfo );
}
static void btreeParseCell(
MemPage pPage, /* Page containing the cell */
int iCell, /* The cell index. First cell is 0 */
ref CellInfo pInfo /* Fill in this structure */
)
{
parseCell( pPage, iCell, ref pInfo );
}
/*
** Compute the total number of bytes that a Cell needs in the cell
** data area of the btree-page. The return number includes the cell
** data header and the local payload, but not any overflow page or
** the space used by the cell pointer.
*/
// Alternative form for C#
static u16 cellSizePtr( MemPage pPage, int iCell )
{
CellInfo info = new CellInfo();
byte[] pCell = new byte[13];
// Minimum Size = (2 bytes of Header or (4) Child Pointer) + (maximum of) 9 bytes data
if ( iCell < 0 )// Overflow Cell
Buffer.BlockCopy( pPage.aOvfl[-( iCell + 1 )].pCell, 0, pCell, 0, pCell.Length < pPage.aOvfl[-( iCell + 1 )].pCell.Length ? pCell.Length : pPage.aOvfl[-( iCell + 1 )].pCell.Length );
else if ( iCell >= pPage.aData.Length + 1 - pCell.Length )
Buffer.BlockCopy( pPage.aData, iCell, pCell, 0, pPage.aData.Length - iCell );
else
Buffer.BlockCopy( pPage.aData, iCell, pCell, 0, pCell.Length );
btreeParseCellPtr( pPage, pCell, ref info );
return info.nSize;
}
// Alternative form for C#
static u16 cellSizePtr( MemPage pPage, byte[] pCell, int offset )
{
CellInfo info = new CellInfo();
info.pCell = sqlite3Malloc( pCell.Length );
Buffer.BlockCopy( pCell, offset, info.pCell, 0, pCell.Length - offset );
btreeParseCellPtr( pPage, info.pCell, ref info );
return info.nSize;
}
static u16 cellSizePtr( MemPage pPage, u8[] pCell )
{
int _pIter = pPage.childPtrSize; //u8 pIter = &pCell[pPage.childPtrSize];
u32 nSize = 0;
#if SQLITE_DEBUG || DEBUG
/* The value returned by this function should always be the same as
** the (CellInfo.nSize) value found by doing a full parse of the
** cell. If SQLITE_DEBUG is defined, an Debug.Assert() at the bottom of
** this function verifies that this invariant is not violated. */
CellInfo debuginfo = new CellInfo();
btreeParseCellPtr( pPage, pCell, ref debuginfo );
#else
CellInfo debuginfo = new CellInfo();
#endif
if ( pPage.intKey != 0 )
{
int pEnd;
if ( pPage.hasData != 0 )
{
_pIter += getVarint32( pCell, out nSize );// pIter += getVarint32( pIter, out nSize );
}
else
{
nSize = 0;
}
/* pIter now points at the 64-bit integer key value, a variable length
** integer. The following block moves pIter to point at the first byte
** past the end of the key value. */
pEnd = _pIter + 9;//pEnd = &pIter[9];
while ( ( ( pCell[_pIter++] ) & 0x80 ) != 0 && _pIter < pEnd )
;//while( (pIter++)&0x80 && pIter<pEnd );
}
else
{
_pIter += getVarint32( pCell, _pIter, out nSize ); //pIter += getVarint32( pIter, out nSize );
}
testcase( nSize == pPage.maxLocal );
testcase( nSize == pPage.maxLocal + 1 );
if ( nSize > pPage.maxLocal )
{
int minLocal = pPage.minLocal;
nSize = (u32)( minLocal + ( nSize - minLocal ) % ( pPage.pBt.usableSize - 4 ) );
testcase( nSize == pPage.maxLocal );
testcase( nSize == pPage.maxLocal + 1 );
if ( nSize > pPage.maxLocal )
{
nSize = (u32)minLocal;
}
nSize += 4;
}
nSize += (uint)_pIter;//nSize += (u32)(pIter - pCell);
/* The minimum size of any cell is 4 bytes. */
if ( nSize < 4 )
{
nSize = 4;
}
Debug.Assert( nSize == debuginfo.nSize );
return (u16)nSize;
}
#if SQLITE_DEBUG
/* This variation on cellSizePtr() is used inside of assert() statements
** only. */
static u16 cellSize( MemPage pPage, int iCell )
{
return cellSizePtr( pPage, findCell( pPage, iCell ) );
}
#else
static int cellSize(MemPage pPage, int iCell) { return -1; }
#endif
#if !SQLITE_OMIT_AUTOVACUUM
/*
** If the cell pCell, part of page pPage contains a pointer
** to an overflow page, insert an entry into the pointer-map
** for the overflow page.
*/
static void ptrmapPutOvflPtr( MemPage pPage, int pCell, ref int pRC )
{
if ( pRC != 0 )
return;
CellInfo info = new CellInfo();
Debug.Assert( pCell != 0 );
btreeParseCellPtr( pPage, pCell, ref info );
Debug.Assert( ( info.nData + ( pPage.intKey != 0 ? 0 : info.nKey ) ) == info.nPayload );
if ( info.iOverflow != 0 )
{
Pgno ovfl = sqlite3Get4byte( pPage.aData, pCell, info.iOverflow );
ptrmapPut( pPage.pBt, ovfl, PTRMAP_OVERFLOW1, pPage.pgno, ref pRC );
}
}
static void ptrmapPutOvflPtr( MemPage pPage, u8[] pCell, ref int pRC )
{
if ( pRC != 0 )
return;
CellInfo info = new CellInfo();
Debug.Assert( pCell != null );
btreeParseCellPtr( pPage, pCell, ref info );
Debug.Assert( ( info.nData + ( pPage.intKey != 0 ? 0 : info.nKey ) ) == info.nPayload );
if ( info.iOverflow != 0 )
{
Pgno ovfl = sqlite3Get4byte( pCell, info.iOverflow );
ptrmapPut( pPage.pBt, ovfl, PTRMAP_OVERFLOW1, pPage.pgno, ref pRC );
}
}
#endif
/*
** Defragment the page given. All Cells are moved to the
** end of the page and all free space is collected into one
** big FreeBlk that occurs in between the header and cell
** pointer array and the cell content area.
*/
static int defragmentPage( MemPage pPage )
{
int i; /* Loop counter */
int pc; /* Address of a i-th cell */
int addr; /* Offset of first byte after cell pointer array */
int hdr; /* Offset to the page header */
int size; /* Size of a cell */
int usableSize; /* Number of usable bytes on a page */
int cellOffset; /* Offset to the cell pointer array */
int cbrk; /* Offset to the cell content area */
int nCell; /* Number of cells on the page */
byte[] data; /* The page data */
byte[] temp; /* Temp area for cell content */
int iCellFirst; /* First allowable cell index */
int iCellLast; /* Last possible cell index */
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
Debug.Assert( pPage.pBt != null );
Debug.Assert( pPage.pBt.usableSize <= SQLITE_MAX_PAGE_SIZE );
Debug.Assert( pPage.nOverflow == 0 );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
temp = sqlite3PagerTempSpace( pPage.pBt.pPager );
data = pPage.aData;
hdr = pPage.hdrOffset;
cellOffset = pPage.cellOffset;
nCell = pPage.nCell;
Debug.Assert( nCell == get2byte( data, hdr + 3 ) );
usableSize = (int)pPage.pBt.usableSize;
cbrk = get2byte( data, hdr + 5 );
Buffer.BlockCopy( data, cbrk, temp, cbrk, usableSize - cbrk );//memcpy( temp[cbrk], ref data[cbrk], usableSize - cbrk );
cbrk = usableSize;
iCellFirst = cellOffset + 2 * nCell;
iCellLast = usableSize - 4;
for ( i = 0; i < nCell; i++ )
{
int pAddr; /* The i-th cell pointer */
pAddr = cellOffset + i * 2; // &data[cellOffset + i * 2];
pc = get2byte( data, pAddr );
testcase( pc == iCellFirst );
testcase( pc == iCellLast );
#if !SQLITE_ENABLE_OVERSIZE_CELL_CHECK
/* These conditions have already been verified in btreeInitPage()
** if SQLITE_ENABLE_OVERSIZE_CELL_CHECK is defined
*/
if ( pc < iCellFirst || pc > iCellLast )
{
return SQLITE_CORRUPT_BKPT();
}
#endif
Debug.Assert( pc >= iCellFirst && pc <= iCellLast );
size = cellSizePtr( pPage, temp, pc );
cbrk -= size;
#if SQLITE_ENABLE_OVERSIZE_CELL_CHECK
if ( cbrk < iCellFirst || pc + size > usableSize )
{
return SQLITE_CORRUPT_BKPT();
}
#else
if ( cbrk < iCellFirst || pc + size > usableSize )
{
return SQLITE_CORRUPT_BKPT();
}
#endif
Debug.Assert( cbrk + size <= usableSize && cbrk >= iCellFirst );
testcase( cbrk + size == usableSize );
testcase( pc + size == usableSize );
Buffer.BlockCopy( temp, pc, data, cbrk, size );//memcpy(data[cbrk], ref temp[pc], size);
put2byte( data, pAddr, cbrk );
}
Debug.Assert( cbrk >= iCellFirst );
put2byte( data, hdr + 5, cbrk );
data[hdr + 1] = 0;
data[hdr + 2] = 0;
data[hdr + 7] = 0;
addr = cellOffset + 2 * nCell;
Array.Clear( data, addr, cbrk - addr ); //memset(data[iCellFirst], 0, cbrk-iCellFirst);
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
if ( cbrk - iCellFirst != pPage.nFree )
{
return SQLITE_CORRUPT_BKPT();
}
return SQLITE_OK;
}
/*
** Allocate nByte bytes of space from within the B-Tree page passed
** as the first argument. Write into pIdx the index into pPage.aData[]
** of the first byte of allocated space. Return either SQLITE_OK or
** an error code (usually SQLITE_CORRUPT).
**
** The caller guarantees that there is sufficient space to make the
** allocation. This routine might need to defragment in order to bring
** all the space together, however. This routine will avoid using
** the first two bytes past the cell pointer area since presumably this
** allocation is being made in order to insert a new cell, so we will
** also end up needing a new cell pointer.
*/
static int allocateSpace( MemPage pPage, int nByte, ref int pIdx )
{
int hdr = pPage.hdrOffset; /* Local cache of pPage.hdrOffset */
u8[] data = pPage.aData; /* Local cache of pPage.aData */
int nFrag; /* Number of fragmented bytes on pPage */
int top; /* First byte of cell content area */
int gap; /* First byte of gap between cell pointers and cell content */
int rc; /* Integer return code */
u32 usableSize; /* Usable size of the page */
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
Debug.Assert( pPage.pBt != null );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( nByte >= 0 ); /* Minimum cell size is 4 */
Debug.Assert( pPage.nFree >= nByte );
Debug.Assert( pPage.nOverflow == 0 );
usableSize = pPage.pBt.usableSize;
Debug.Assert( nByte < usableSize - 8 );
nFrag = data[hdr + 7];
Debug.Assert( pPage.cellOffset == hdr + 12 - 4 * pPage.leaf );
gap = pPage.cellOffset + 2 * pPage.nCell;
top = get2byteNotZero( data, hdr + 5 );
if ( gap > top )
return SQLITE_CORRUPT_BKPT();
testcase( gap + 2 == top );
testcase( gap + 1 == top );
testcase( gap == top );
if ( nFrag >= 60 )
{
/* Always defragment highly fragmented pages */
rc = defragmentPage( pPage );
if ( rc != 0 )
return rc;
top = get2byteNotZero( data, hdr + 5 );
}
else if ( gap + 2 <= top )
{
/* Search the freelist looking for a free slot big enough to satisfy
** the request. The allocation is made from the first free slot in
** the list that is large enough to accomadate it.
*/
int pc, addr;
for ( addr = hdr + 1; ( pc = get2byte( data, addr ) ) > 0; addr = pc )
{
int size; /* Size of free slot */
if ( pc > usableSize - 4 || pc < addr + 4 )
{
return SQLITE_CORRUPT_BKPT();
}
size = get2byte( data, pc + 2 );
if ( size >= nByte )
{
int x = size - nByte;
testcase( x == 4 );
testcase( x == 3 );
if ( x < 4 )
{
/* Remove the slot from the free-list. Update the number of
** fragmented bytes within the page. */
data[addr + 0] = data[pc + 0];
data[addr + 1] = data[pc + 1]; //memcpy( data[addr], ref data[pc], 2 );
data[hdr + 7] = (u8)( nFrag + x );
}
else if ( size + pc > usableSize )
{
return SQLITE_CORRUPT_BKPT();
}
else
{
/* The slot remains on the free-list. Reduce its size to account
** for the portion used by the new allocation. */
put2byte( data, pc + 2, x );
}
pIdx = pc + x;
return SQLITE_OK;
}
}
}
/* Check to make sure there is enough space in the gap to satisfy
** the allocation. If not, defragment.
*/
testcase( gap + 2 + nByte == top );
if ( gap + 2 + nByte > top )
{
rc = defragmentPage( pPage );
if ( rc != 0 )
return rc;
top = get2byteNotZero( data, hdr + 5 );
Debug.Assert( gap + nByte <= top );
}
/* Allocate memory from the gap in between the cell pointer array
** and the cell content area. The btreeInitPage() call has already
** validated the freelist. Given that the freelist is valid, there
** is no way that the allocation can extend off the end of the page.
** The Debug.Assert() below verifies the previous sentence.
*/
top -= nByte;
put2byte( data, hdr + 5, top );
Debug.Assert( top + nByte <= (int)pPage.pBt.usableSize );
pIdx = top;
return SQLITE_OK;
}
/*
** Return a section of the pPage.aData to the freelist.
** The first byte of the new free block is pPage.aDisk[start]
** and the size of the block is "size" bytes.
**
** Most of the effort here is involved in coalesing adjacent
** free blocks into a single big free block.
*/
static int freeSpace( MemPage pPage, u32 start, int size )
{
return freeSpace( pPage, (int)start, size );
}
static int freeSpace( MemPage pPage, int start, int size )
{
int addr, pbegin, hdr;
int iLast; /* Largest possible freeblock offset */
byte[] data = pPage.aData;
Debug.Assert( pPage.pBt != null );
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
Debug.Assert( start >= pPage.hdrOffset + 6 + pPage.childPtrSize );
Debug.Assert( ( start + size ) <= (int)pPage.pBt.usableSize );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( size >= 0 ); /* Minimum cell size is 4 */
if ( pPage.pBt.secureDelete )
{
/* Overwrite deleted information with zeros when the secure_delete
** option is enabled */
Array.Clear( data, start, size );// memset(&data[start], 0, size);
}
/* Add the space back into the linked list of freeblocks. Note that
** even though the freeblock list was checked by btreeInitPage(),
** btreeInitPage() did not detect overlapping cells or
** freeblocks that overlapped cells. Nor does it detect when the
** cell content area exceeds the value in the page header. If these
** situations arise, then subsequent insert operations might corrupt
** the freelist. So we do need to check for corruption while scanning
** the freelist.
*/
hdr = pPage.hdrOffset;
addr = hdr + 1;
iLast = (int)pPage.pBt.usableSize - 4;
Debug.Assert( start <= iLast );
while ( ( pbegin = get2byte( data, addr ) ) < start && pbegin > 0 )
{
if ( pbegin < addr + 4 )
{
return SQLITE_CORRUPT_BKPT();
}
addr = pbegin;
}
if ( pbegin > iLast )
{
return SQLITE_CORRUPT_BKPT();
}
Debug.Assert( pbegin > addr || pbegin == 0 );
put2byte( data, addr, start );
put2byte( data, start, pbegin );
put2byte( data, start + 2, size );
pPage.nFree = (u16)( pPage.nFree + size );
/* Coalesce adjacent free blocks */
addr = hdr + 1;
while ( ( pbegin = get2byte( data, addr ) ) > 0 )
{
int pnext, psize, x;
Debug.Assert( pbegin > addr );
Debug.Assert( pbegin <= (int)pPage.pBt.usableSize - 4 );
pnext = get2byte( data, pbegin );
psize = get2byte( data, pbegin + 2 );
if ( pbegin + psize + 3 >= pnext && pnext > 0 )
{
int frag = pnext - ( pbegin + psize );
if ( ( frag < 0 ) || ( frag > (int)data[hdr + 7] ) )
{
return SQLITE_CORRUPT_BKPT();
}
data[hdr + 7] -= (u8)frag;
x = get2byte( data, pnext );
put2byte( data, pbegin, x );
x = pnext + get2byte( data, pnext + 2 ) - pbegin;
put2byte( data, pbegin + 2, x );
}
else
{
addr = pbegin;
}
}
/* If the cell content area begins with a freeblock, remove it. */
if ( data[hdr + 1] == data[hdr + 5] && data[hdr + 2] == data[hdr + 6] )
{
int top;
pbegin = get2byte( data, hdr + 1 );
put2byte( data, hdr + 1, get2byte( data, pbegin ) ); //memcpy( data[hdr + 1], ref data[pbegin], 2 );
top = get2byte( data, hdr + 5 ) + get2byte( data, pbegin + 2 );
put2byte( data, hdr + 5, top );
}
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
return SQLITE_OK;
}
/*
** Decode the flags byte (the first byte of the header) for a page
** and initialize fields of the MemPage structure accordingly.
**
** Only the following combinations are supported. Anything different
** indicates a corrupt database files:
**
** PTF_ZERODATA
** PTF_ZERODATA | PTF_LEAF
** PTF_LEAFDATA | PTF_INTKEY
** PTF_LEAFDATA | PTF_INTKEY | PTF_LEAF
*/
static int decodeFlags( MemPage pPage, int flagByte )
{
BtShared pBt; /* A copy of pPage.pBt */
Debug.Assert( pPage.hdrOffset == ( pPage.pgno == 1 ? 100 : 0 ) );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
pPage.leaf = (u8)( flagByte >> 3 );
Debug.Assert( PTF_LEAF == 1 << 3 );
flagByte &= ~PTF_LEAF;
pPage.childPtrSize = (u8)( 4 - 4 * pPage.leaf );
pBt = pPage.pBt;
if ( flagByte == ( PTF_LEAFDATA | PTF_INTKEY ) )
{
pPage.intKey = 1;
pPage.hasData = pPage.leaf;
pPage.maxLocal = pBt.maxLeaf;
pPage.minLocal = pBt.minLeaf;
}
else if ( flagByte == PTF_ZERODATA )
{
pPage.intKey = 0;
pPage.hasData = 0;
pPage.maxLocal = pBt.maxLocal;
pPage.minLocal = pBt.minLocal;
}
else
{
return SQLITE_CORRUPT_BKPT();
}
return SQLITE_OK;
}
/*
** Initialize the auxiliary information for a disk block.
**
** Return SQLITE_OK on success. If we see that the page does
** not contain a well-formed database page, then return
** SQLITE_CORRUPT. Note that a return of SQLITE_OK does not
** guarantee that the page is well-formed. It only shows that
** we failed to detect any corruption.
*/
static int btreeInitPage( MemPage pPage )
{
Debug.Assert( pPage.pBt != null );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( pPage.pgno == sqlite3PagerPagenumber( pPage.pDbPage ) );
Debug.Assert( pPage == sqlite3PagerGetExtra( pPage.pDbPage ) );
Debug.Assert( pPage.aData == sqlite3PagerGetData( pPage.pDbPage ) );
if ( 0 == pPage.isInit )
{
u16 pc; /* Address of a freeblock within pPage.aData[] */
u8 hdr; /* Offset to beginning of page header */
u8[] data; /* Equal to pPage.aData */
BtShared pBt; /* The main btree structure */
int usableSize; /* Amount of usable space on each page */
u16 cellOffset; /* Offset from start of page to first cell pointer */
int nFree; /* Number of unused bytes on the page */
int top; /* First byte of the cell content area */
int iCellFirst; /* First allowable cell or freeblock offset */
int iCellLast; /* Last possible cell or freeblock offset */
pBt = pPage.pBt;
hdr = pPage.hdrOffset;
data = pPage.aData;
if ( decodeFlags( pPage, data[hdr] ) != 0 )
return SQLITE_CORRUPT_BKPT();
Debug.Assert( pBt.pageSize >= 512 && pBt.pageSize <= 65536 );
pPage.maskPage = (u16)( pBt.pageSize - 1 );
pPage.nOverflow = 0;
usableSize = (int)pBt.usableSize;
pPage.cellOffset = ( cellOffset = (u16)( hdr + 12 - 4 * pPage.leaf ) );
top = get2byteNotZero( data, hdr + 5 );
pPage.nCell = (u16)( get2byte( data, hdr + 3 ) );
if ( pPage.nCell > MX_CELL( pBt ) )
{
/* To many cells for a single page. The page must be corrupt */
return SQLITE_CORRUPT_BKPT();
}
testcase( pPage.nCell == MX_CELL( pBt ) );
/* A malformed database page might cause us to read past the end
** of page when parsing a cell.
**
** The following block of code checks early to see if a cell extends
** past the end of a page boundary and causes SQLITE_CORRUPT to be
** returned if it does.
*/
iCellFirst = cellOffset + 2 * pPage.nCell;
iCellLast = usableSize - 4;
#if SQLITE_ENABLE_OVERSIZE_CELL_CHECK
{
int i; /* Index into the cell pointer array */
int sz; /* Size of a cell */
if ( 0 == pPage.leaf )
iCellLast--;
for ( i = 0; i < pPage.nCell; i++ )
{
pc = (u16)get2byte( data, cellOffset + i * 2 );
testcase( pc == iCellFirst );
testcase( pc == iCellLast );
if ( pc < iCellFirst || pc > iCellLast )
{
return SQLITE_CORRUPT_BKPT();
}
sz = cellSizePtr( pPage, data, pc );
testcase( pc + sz == usableSize );
if ( pc + sz > usableSize )
{
return SQLITE_CORRUPT_BKPT();
}
}
if ( 0 == pPage.leaf )
iCellLast++;
}
#endif
/* Compute the total free space on the page */
pc = (u16)get2byte( data, hdr + 1 );
nFree = (u16)( data[hdr + 7] + top );
while ( pc > 0 )
{
u16 next, size;
if ( pc < iCellFirst || pc > iCellLast )
{
/* Start of free block is off the page */
return SQLITE_CORRUPT_BKPT();
}
next = (u16)get2byte( data, pc );
size = (u16)get2byte( data, pc + 2 );
if ( ( next > 0 && next <= pc + size + 3 ) || pc + size > usableSize )
{
/* Free blocks must be in ascending order. And the last byte of
** the free-block must lie on the database page. */
return SQLITE_CORRUPT_BKPT();
}
nFree = (u16)( nFree + size );
pc = next;
}
/* At this point, nFree contains the sum of the offset to the start
** of the cell-content area plus the number of free bytes within
** the cell-content area. If this is greater than the usable-size
** of the page, then the page must be corrupted. This check also
** serves to verify that the offset to the start of the cell-content
** area, according to the page header, lies within the page.
*/
if ( nFree > usableSize )
{
return SQLITE_CORRUPT_BKPT();
}
pPage.nFree = (u16)( nFree - iCellFirst );
pPage.isInit = 1;
}
return SQLITE_OK;
}
/*
** Set up a raw page so that it looks like a database page holding
** no entries.
*/
static void zeroPage( MemPage pPage, int flags )
{
byte[] data = pPage.aData;
BtShared pBt = pPage.pBt;
u8 hdr = pPage.hdrOffset;
u16 first;
Debug.Assert( sqlite3PagerPagenumber( pPage.pDbPage ) == pPage.pgno );
Debug.Assert( sqlite3PagerGetExtra( pPage.pDbPage ) == pPage );
Debug.Assert( sqlite3PagerGetData( pPage.pDbPage ) == data );
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
if ( pBt.secureDelete )
{
Array.Clear( data, hdr, (int)( pBt.usableSize - hdr ) );//memset(&data[hdr], 0, pBt->usableSize - hdr);
}
data[hdr] = (u8)flags;
first = (u16)( hdr + 8 + 4 * ( ( flags & PTF_LEAF ) == 0 ? 1 : 0 ) );
Array.Clear( data, hdr + 1, 4 );//memset(data[hdr+1], 0, 4);
data[hdr + 7] = 0;
put2byte( data, hdr + 5, pBt.usableSize );
pPage.nFree = (u16)( pBt.usableSize - first );
decodeFlags( pPage, flags );
pPage.hdrOffset = hdr;
pPage.cellOffset = first;
pPage.nOverflow = 0;
Debug.Assert( pBt.pageSize >= 512 && pBt.pageSize <= 65536 );
pPage.maskPage = (u16)( pBt.pageSize - 1 );
pPage.nCell = 0;
pPage.isInit = 1;
}
/*
** Convert a DbPage obtained from the pager into a MemPage used by
** the btree layer.
*/
static MemPage btreePageFromDbPage( DbPage pDbPage, Pgno pgno, BtShared pBt )
{
MemPage pPage = (MemPage)sqlite3PagerGetExtra( pDbPage );
pPage.aData = sqlite3PagerGetData( pDbPage );
pPage.pDbPage = pDbPage;
pPage.pBt = pBt;
pPage.pgno = pgno;
pPage.hdrOffset = (u8)( pPage.pgno == 1 ? 100 : 0 );
return pPage;
}
/*
** Get a page from the pager. Initialize the MemPage.pBt and
** MemPage.aData elements if needed.
**
** If the noContent flag is set, it means that we do not care about
** the content of the page at this time. So do not go to the disk
** to fetch the content. Just fill in the content with zeros for now.
** If in the future we call sqlite3PagerWrite() on this page, that
** means we have started to be concerned about content and the disk
** read should occur at that point.
*/
static int btreeGetPage(
BtShared pBt, /* The btree */
Pgno pgno, /* Number of the page to fetch */
ref MemPage ppPage, /* Return the page in this parameter */
int noContent /* Do not load page content if true */
)
{
int rc;
DbPage pDbPage = null;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
rc = sqlite3PagerAcquire( pBt.pPager, pgno, ref pDbPage, (u8)noContent );
if ( rc != 0 )
return rc;
ppPage = btreePageFromDbPage( pDbPage, pgno, pBt );
return SQLITE_OK;
}
/*
** Retrieve a page from the pager cache. If the requested page is not
** already in the pager cache return NULL. Initialize the MemPage.pBt and
** MemPage.aData elements if needed.
*/
static MemPage btreePageLookup( BtShared pBt, Pgno pgno )
{
DbPage pDbPage;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
pDbPage = sqlite3PagerLookup( pBt.pPager, pgno );
if ( pDbPage )
{
return btreePageFromDbPage( pDbPage, pgno, pBt );
}
return null;
}
/*
** Return the size of the database file in pages. If there is any kind of
** error, return ((unsigned int)-1).
*/
static Pgno btreePagecount( BtShared pBt )
{
return pBt.nPage;
}
static Pgno sqlite3BtreeLastPage( Btree p )
{
Debug.Assert( sqlite3BtreeHoldsMutex( p ) );
Debug.Assert( ( ( p.pBt.nPage ) & 0x8000000 ) == 0 );
return (Pgno)btreePagecount( p.pBt );
}
/*
** Get a page from the pager and initialize it. This routine is just a
** convenience wrapper around separate calls to btreeGetPage() and
** btreeInitPage().
**
** If an error occurs, then the value ppPage is set to is undefined. It
** may remain unchanged, or it may be set to an invalid value.
*/
static int getAndInitPage(
BtShared pBt, /* The database file */
Pgno pgno, /* Number of the page to get */
ref MemPage ppPage /* Write the page pointer here */
)
{
int rc;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
if ( pgno > btreePagecount( pBt ) )
{
rc = SQLITE_CORRUPT_BKPT();
}
else
{
rc = btreeGetPage( pBt, pgno, ref ppPage, 0 );
if ( rc == SQLITE_OK )
{
rc = btreeInitPage( ppPage );
if ( rc != SQLITE_OK )
{
releasePage( ppPage );
}
}
}
testcase( pgno == 0 );
Debug.Assert( pgno != 0 || rc == SQLITE_CORRUPT );
return rc;
}
/*
** Release a MemPage. This should be called once for each prior
** call to btreeGetPage.
*/
static void releasePage( MemPage pPage )
{
if ( pPage != null )
{
Debug.Assert( pPage.aData != null );
Debug.Assert( pPage.pBt != null );
//TODO -- find out why corrupt9 & diskfull fail on this tests
//Debug.Assert( sqlite3PagerGetExtra( pPage.pDbPage ) == pPage );
//Debug.Assert( sqlite3PagerGetData( pPage.pDbPage ) == pPage.aData );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
sqlite3PagerUnref( pPage.pDbPage );
}
}
/*
** During a rollback, when the pager reloads information into the cache
** so that the cache is restored to its original state at the start of
** the transaction, for each page restored this routine is called.
**
** This routine needs to reset the extra data section at the end of the
** page to agree with the restored data.
*/
static void pageReinit( DbPage pData )
{
MemPage pPage;
pPage = sqlite3PagerGetExtra( pData );
Debug.Assert( sqlite3PagerPageRefcount( pData ) > 0 );
if ( pPage.isInit != 0 )
{
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
pPage.isInit = 0;
if ( sqlite3PagerPageRefcount( pData ) > 1 )
{
/* pPage might not be a btree page; it might be an overflow page
** or ptrmap page or a free page. In those cases, the following
** call to btreeInitPage() will likely return SQLITE_CORRUPT.
** But no harm is done by this. And it is very important that
** btreeInitPage() be called on every btree page so we make
** the call for every page that comes in for re-initing. */
btreeInitPage( pPage );
}
}
}
/*
** Invoke the busy handler for a btree.
*/
static int btreeInvokeBusyHandler( object pArg )
{
BtShared pBt = (BtShared)pArg;
Debug.Assert( pBt.db != null );
Debug.Assert( sqlite3_mutex_held( pBt.db.mutex ) );
return sqlite3InvokeBusyHandler( pBt.db.busyHandler );
}
/*
** Open a database file.
**
** zFilename is the name of the database file. If zFilename is NULL
** then an ephemeral database is created. The ephemeral database might
** be exclusively in memory, or it might use a disk-based memory cache.
** Either way, the ephemeral database will be automatically deleted
** when sqlite3BtreeClose() is called.
**
** If zFilename is ":memory:" then an in-memory database is created
** that is automatically destroyed when it is closed.
**
** The "flags" parameter is a bitmask that might contain bits
** BTREE_OMIT_JOURNAL and/or BTREE_NO_READLOCK. The BTREE_NO_READLOCK
** bit is also set if the SQLITE_NoReadlock flags is set in db->flags.
** These flags are passed through into sqlite3PagerOpen() and must
** be the same values as PAGER_OMIT_JOURNAL and PAGER_NO_READLOCK.
**
** If the database is already opened in the same database connection
** and we are in shared cache mode, then the open will fail with an
** SQLITE_CONSTRAINT error. We cannot allow two or more BtShared
** objects in the same database connection since doing so will lead
** to problems with locking.
*/
static int sqlite3BtreeOpen(
sqlite3_vfs pVfs, /* VFS to use for this b-tree */
string zFilename, /* Name of the file containing the BTree database */
sqlite3 db, /* Associated database handle */
ref Btree ppBtree, /* Pointer to new Btree object written here */
int flags, /* Options */
int vfsFlags /* Flags passed through to sqlite3_vfs.xOpen() */
)
{
BtShared pBt = null; /* Shared part of btree structure */
Btree p; /* Handle to return */
sqlite3_mutex mutexOpen = null; /* Prevents a race condition. Ticket #3537 */
int rc = SQLITE_OK; /* Result code from this function */
u8 nReserve; /* Byte of unused space on each page */
byte[] zDbHeader = new byte[100]; /* Database header content */
/* True if opening an ephemeral, temporary database */
bool isTempDb = string.IsNullOrEmpty( zFilename );//zFilename==0 || zFilename[0]==0;
/* Set the variable isMemdb to true for an in-memory database, or
** false for a file-based database.
*/
#if SQLITE_OMIT_MEMORYDB
bool isMemdb = false;
#else
bool isMemdb = ( zFilename == ":memory:" )
|| ( isTempDb && sqlite3TempInMemory( db ) );
#endif
Debug.Assert( db != null );
Debug.Assert( pVfs != null );
Debug.Assert( sqlite3_mutex_held( db.mutex ) );
Debug.Assert( ( flags & 0xff ) == flags ); /* flags fit in 8 bits */
/* Only a BTREE_SINGLE database can be BTREE_UNORDERED */
Debug.Assert( ( flags & BTREE_UNORDERED ) == 0 || ( flags & BTREE_SINGLE ) != 0 );
/* A BTREE_SINGLE database is always a temporary and/or ephemeral */
Debug.Assert( ( flags & BTREE_SINGLE ) == 0 || isTempDb );
if ( ( db.flags & SQLITE_NoReadlock ) != 0 )
{
flags |= BTREE_NO_READLOCK;
}
if ( isMemdb )
{
flags |= BTREE_MEMORY;
}
if ( ( vfsFlags & SQLITE_OPEN_MAIN_DB ) != 0 && ( isMemdb || isTempDb ) )
{
vfsFlags = ( vfsFlags & ~SQLITE_OPEN_MAIN_DB ) | SQLITE_OPEN_TEMP_DB;
}
p = new Btree();//sqlite3MallocZero(sizeof(Btree));
//if( !p ){
// return SQLITE_NOMEM;
//}
p.inTrans = TRANS_NONE;
p.db = db;
#if !SQLITE_OMIT_SHARED_CACHE
p.lock.pBtree = p;
p.lock.iTable = 1;
#endif
#if !(SQLITE_OMIT_SHARED_CACHE) && !(SQLITE_OMIT_DISKIO)
/*
** If this Btree is a candidate for shared cache, try to find an
** existing BtShared object that we can share with
*/
if( !isMemdb && !isTempDb ){
if( vfsFlags & SQLITE_OPEN_SHAREDCACHE ){
int nFullPathname = pVfs.mxPathname+1;
string zFullPathname = sqlite3Malloc(nFullPathname);
sqlite3_mutex *mutexShared;
p.sharable = 1;
if( !zFullPathname ){
p = null;//sqlite3_free(ref p);
return SQLITE_NOMEM;
}
sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
sqlite3_mutex_enter(mutexOpen);
mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
sqlite3_mutex_enter(mutexShared);
for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt.pNext){
Debug.Assert( pBt.nRef>0 );
if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt.pPager))
&& sqlite3PagerVfs(pBt.pPager)==pVfs ){
int iDb;
for(iDb=db.nDb-1; iDb>=0; iDb--){
Btree pExisting = db.aDb[iDb].pBt;
if( pExisting && pExisting.pBt==pBt ){
sqlite3_mutex_leave(mutexShared);
sqlite3_mutex_leave(mutexOpen);
zFullPathname = null;//sqlite3_free(ref zFullPathname);
p=null;//sqlite3_free(ref p);
return SQLITE_CONSTRAINT;
}
}
p.pBt = pBt;
pBt.nRef++;
break;
}
}
sqlite3_mutex_leave(mutexShared);
zFullPathname=null;//sqlite3_free(ref zFullPathname);
}
#if SQLITE_DEBUG
else{
/* In debug mode, we mark all persistent databases as sharable
** even when they are not. This exercises the locking code and
** gives more opportunity for asserts(sqlite3_mutex_held())
** statements to find locking problems.
*/
p.sharable = 1;
}
#endif
}
#endif
if ( pBt == null )
{
/*
** The following asserts make sure that structures used by the btree are
** the right size. This is to guard against size changes that result
** when compiling on a different architecture.
*/
// These are defined as constants in the CLI specifications.
// (See, for example, C# spec sections 18.5.8 and 4.1.4)
////Debug.Assert( sizeof( i64 ) == 8 || sizeof( i64 ) == 4 );
////Debug.Assert( sizeof( u64 ) == 8 || sizeof( u64 ) == 4 );
////Debug.Assert( sizeof( u32 ) == 4 );
////Debug.Assert( sizeof( u16 ) == 2 );
////Debug.Assert( sizeof( Pgno ) == 4 );
pBt = new BtShared();//sqlite3MallocZero( sizeof(pBt) );
//if( pBt==null ){
// rc = SQLITE_NOMEM;
// goto btree_open_out;
//}
rc = sqlite3PagerOpen( pVfs, out pBt.pPager, zFilename,
EXTRA_SIZE, flags, vfsFlags, pageReinit );
if ( rc == SQLITE_OK )
{
rc = sqlite3PagerReadFileheader( pBt.pPager, zDbHeader.Length, zDbHeader );
}
if ( rc != SQLITE_OK )
{
goto btree_open_out;
}
pBt.openFlags = (u8)flags;
pBt.db = db;
sqlite3PagerSetBusyhandler( pBt.pPager, btreeInvokeBusyHandler, pBt );
p.pBt = pBt;
pBt.pCursor = null;
pBt.pPage1 = null;
pBt.readOnly = sqlite3PagerIsreadonly( pBt.pPager );
#if SQLITE_SECURE_DELETE
pBt.secureDelete = true;
#endif
pBt.pageSize = (u32)( ( zDbHeader[16] << 8 ) | ( zDbHeader[17] << 16 ) );
if ( pBt.pageSize < 512 || pBt.pageSize > SQLITE_MAX_PAGE_SIZE
|| ( ( pBt.pageSize - 1 ) & pBt.pageSize ) != 0 )
{
pBt.pageSize = 0;
#if !SQLITE_OMIT_AUTOVACUUM
/* If the magic name ":memory:" will create an in-memory database, then
** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
** SQLITE_DEFAULT_AUTOVACUUM is true. On the other hand, if
** SQLITE_OMIT_MEMORYDB has been defined, then ":memory:" is just a
** regular file-name. In this case the auto-vacuum applies as per normal.
*/
if (zFilename != null && zFilename.Length > 0 && !isMemdb )
{
pBt.autoVacuum = ( SQLITE_DEFAULT_AUTOVACUUM != 0 );
pBt.incrVacuum = ( SQLITE_DEFAULT_AUTOVACUUM == 2 );
}
#endif
nReserve = 0;
}
else
{
nReserve = zDbHeader[20];
pBt.pageSizeFixed = true;
#if !SQLITE_OMIT_AUTOVACUUM
pBt.autoVacuum = sqlite3Get4byte( zDbHeader, 36 + 4 * 4 ) != 0;
pBt.incrVacuum = sqlite3Get4byte( zDbHeader, 36 + 7 * 4 ) != 0;
#endif
}
rc = sqlite3PagerSetPagesize( pBt.pPager, ref pBt.pageSize, nReserve );
if ( rc != 0 )
goto btree_open_out;
pBt.usableSize = (u16)( pBt.pageSize - nReserve );
Debug.Assert( ( pBt.pageSize & 7 ) == 0 ); /* 8-byte alignment of pageSize */
#if !(SQLITE_OMIT_SHARED_CACHE) && !(SQLITE_OMIT_DISKIO)
/* Add the new BtShared object to the linked list sharable BtShareds.
*/
if( p.sharable ){
sqlite3_mutex *mutexShared;
pBt.nRef = 1;
mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
if( SQLITE_THREADSAFE && sqlite3GlobalConfig.bCoreMutex ){
pBt.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_FAST);
if( pBt.mutex==null ){
rc = SQLITE_NOMEM;
db.mallocFailed = 0;
goto btree_open_out;
}
}
sqlite3_mutex_enter(mutexShared);
pBt.pNext = GLOBAL(BtShared*,sqlite3SharedCacheList);
GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt;
sqlite3_mutex_leave(mutexShared);
}
#endif
}
#if !(SQLITE_OMIT_SHARED_CACHE) && !(SQLITE_OMIT_DISKIO)
/* If the new Btree uses a sharable pBtShared, then link the new
** Btree into the list of all sharable Btrees for the same connection.
** The list is kept in ascending order by pBt address.
*/
if( p.sharable ){
int i;
Btree pSib;
for(i=0; i<db.nDb; i++){
if( (pSib = db.aDb[i].pBt)!=null && pSib.sharable ){
while( pSib.pPrev ){ pSib = pSib.pPrev; }
if( p.pBt<pSib.pBt ){
p.pNext = pSib;
p.pPrev = 0;
pSib.pPrev = p;
}else{
while( pSib.pNext && pSib.pNext.pBt<p.pBt ){
pSib = pSib.pNext;
}
p.pNext = pSib.pNext;
p.pPrev = pSib;
if( p.pNext ){
p.pNext.pPrev = p;
}
pSib.pNext = p;
}
break;
}
}
}
#endif
ppBtree = p;
btree_open_out:
if ( rc != SQLITE_OK )
{
if ( pBt != null && pBt.pPager != null )
{
sqlite3PagerClose( pBt.pPager );
}
pBt = null; // sqlite3_free(ref pBt);
p = null; // sqlite3_free(ref p);
ppBtree = null;
}
else
{
/* If the B-Tree was successfully opened, set the pager-cache size to the
** default value. Except, when opening on an existing shared pager-cache,
** do not change the pager-cache size.
*/
if ( sqlite3BtreeSchema( p, 0, null ) == null )
{
sqlite3PagerSetCachesize( p.pBt.pPager, SQLITE_DEFAULT_CACHE_SIZE );
}
}
if ( mutexOpen != null )
{
Debug.Assert( sqlite3_mutex_held( mutexOpen ) );
sqlite3_mutex_leave( mutexOpen );
}
return rc;
}
/*
** Decrement the BtShared.nRef counter. When it reaches zero,
** remove the BtShared structure from the sharing list. Return
** true if the BtShared.nRef counter reaches zero and return
** false if it is still positive.
*/
static bool removeFromSharingList( BtShared pBt )
{
#if !SQLITE_OMIT_SHARED_CACHE
sqlite3_mutex pMaster;
BtShared pList;
bool removed = false;
Debug.Assert( sqlite3_mutex_notheld(pBt.mutex) );
pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
sqlite3_mutex_enter(pMaster);
pBt.nRef--;
if( pBt.nRef<=0 ){
if( GLOBAL(BtShared*,sqlite3SharedCacheList)==pBt ){
GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt.pNext;
}else{
pList = GLOBAL(BtShared*,sqlite3SharedCacheList);
while( ALWAYS(pList) && pList.pNext!=pBt ){
pList=pList.pNext;
}
if( ALWAYS(pList) ){
pList.pNext = pBt.pNext;
}
}
if( SQLITE_THREADSAFE ){
sqlite3_mutex_free(pBt.mutex);
}
removed = true;
}
sqlite3_mutex_leave(pMaster);
return removed;
#else
return true;
#endif
}
/*
** Make sure pBt.pTmpSpace points to an allocation of
** MX_CELL_SIZE(pBt) bytes.
*/
static void allocateTempSpace( BtShared pBt )
{
if ( null == pBt.pTmpSpace )
{
pBt.pTmpSpace = sqlite3Malloc( pBt.pageSize );
}
}
/*
** Free the pBt.pTmpSpace allocation
*/
static void freeTempSpace( BtShared pBt )
{
sqlite3PageFree( ref pBt.pTmpSpace );
}
/*
** Close an open database and invalidate all cursors.
*/
static int sqlite3BtreeClose( ref Btree p )
{
BtShared pBt = p.pBt;
BtCursor pCur;
/* Close all cursors opened via this handle. */
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
sqlite3BtreeEnter( p );
pCur = pBt.pCursor;
while ( pCur != null )
{
BtCursor pTmp = pCur;
pCur = pCur.pNext;
if ( pTmp.pBtree == p )
{
sqlite3BtreeCloseCursor( pTmp );
}
}
/* Rollback any active transaction and free the handle structure.
** The call to sqlite3BtreeRollback() drops any table-locks held by
** this handle.
*/
sqlite3BtreeRollback( p );
sqlite3BtreeLeave( p );
/* If there are still other outstanding references to the shared-btree
** structure, return now. The remainder of this procedure cleans
** up the shared-btree.
*/
Debug.Assert( p.wantToLock == 0 && !p.locked );
if ( !p.sharable || removeFromSharingList( pBt ) )
{
/* The pBt is no longer on the sharing list, so we can access
** it without having to hold the mutex.
**
** Clean out and delete the BtShared object.
*/
Debug.Assert( null == pBt.pCursor );
sqlite3PagerClose( pBt.pPager );
if ( pBt.xFreeSchema != null && pBt.pSchema != null )
{
pBt.xFreeSchema( pBt.pSchema );
}
pBt.pSchema = null;// sqlite3DbFree(0, pBt->pSchema);
//freeTempSpace(pBt);
pBt = null; //sqlite3_free(ref pBt);
}
#if !SQLITE_OMIT_SHARED_CACHE
Debug.Assert( p.wantToLock==null );
Debug.Assert( p.locked==null );
if( p.pPrev ) p.pPrev.pNext = p.pNext;
if( p.pNext ) p.pNext.pPrev = p.pPrev;
#endif
//sqlite3_free(ref p);
return SQLITE_OK;
}
/*
** Change the limit on the number of pages allowed in the cache.
**
** The maximum number of cache pages is set to the absolute
** value of mxPage. If mxPage is negative, the pager will
** operate asynchronously - it will not stop to do fsync()s
** to insure data is written to the disk surface before
** continuing. Transactions still work if synchronous is off,
** and the database cannot be corrupted if this program
** crashes. But if the operating system crashes or there is
** an abrupt power failure when synchronous is off, the database
** could be left in an inconsistent and unrecoverable state.
** Synchronous is on by default so database corruption is not
** normally a worry.
*/
static int sqlite3BtreeSetCacheSize( Btree p, int mxPage )
{
BtShared pBt = p.pBt;
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
sqlite3BtreeEnter( p );
sqlite3PagerSetCachesize( pBt.pPager, mxPage );
sqlite3BtreeLeave( p );
return SQLITE_OK;
}
/*
** Change the way data is synced to disk in order to increase or decrease
** how well the database resists damage due to OS crashes and power
** failures. Level 1 is the same as asynchronous (no syncs() occur and
** there is a high probability of damage) Level 2 is the default. There
** is a very low but non-zero probability of damage. Level 3 reduces the
** probability of damage to near zero but with a write performance reduction.
*/
#if !SQLITE_OMIT_PAGER_PRAGMAS
static int sqlite3BtreeSetSafetyLevel(
Btree p, /* The btree to set the safety level on */
int level, /* PRAGMA synchronous. 1=OFF, 2=NORMAL, 3=FULL */
int fullSync, /* PRAGMA fullfsync. */
int ckptFullSync /* PRAGMA checkpoint_fullfync */
)
{
BtShared pBt = p.pBt;
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
Debug.Assert( level >= 1 && level <= 3 );
sqlite3BtreeEnter( p );
sqlite3PagerSetSafetyLevel( pBt.pPager, level, fullSync, ckptFullSync );
sqlite3BtreeLeave( p );
return SQLITE_OK;
}
#endif
/*
** Return TRUE if the given btree is set to safety level 1. In other
** words, return TRUE if no sync() occurs on the disk files.
*/
static int sqlite3BtreeSyncDisabled( Btree p )
{
BtShared pBt = p.pBt;
int rc;
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
sqlite3BtreeEnter( p );
Debug.Assert( pBt != null && pBt.pPager != null );
rc = sqlite3PagerNosync( pBt.pPager ) ? 1 : 0;
sqlite3BtreeLeave( p );
return rc;
}
/*
** Change the default pages size and the number of reserved bytes per page.
** Or, if the page size has already been fixed, return SQLITE_READONLY
** without changing anything.
**
** The page size must be a power of 2 between 512 and 65536. If the page
** size supplied does not meet this constraint then the page size is not
** changed.
**
** Page sizes are constrained to be a power of two so that the region
** of the database file used for locking (beginning at PENDING_BYTE,
** the first byte past the 1GB boundary, 0x40000000) needs to occur
** at the beginning of a page.
**
** If parameter nReserve is less than zero, then the number of reserved
** bytes per page is left unchanged.
**
** If iFix!=0 then the pageSizeFixed flag is set so that the page size
** and autovacuum mode can no longer be changed.
*/
static int sqlite3BtreeSetPageSize( Btree p, int pageSize, int nReserve, int iFix )
{
int rc = SQLITE_OK;
BtShared pBt = p.pBt;
Debug.Assert( nReserve >= -1 && nReserve <= 255 );
sqlite3BtreeEnter( p );
if ( pBt.pageSizeFixed )
{
sqlite3BtreeLeave( p );
return SQLITE_READONLY;
}
if ( nReserve < 0 )
{
nReserve = (int)( pBt.pageSize - pBt.usableSize );
}
Debug.Assert( nReserve >= 0 && nReserve <= 255 );
if ( pageSize >= 512 && pageSize <= SQLITE_MAX_PAGE_SIZE &&
( ( pageSize - 1 ) & pageSize ) == 0 )
{
Debug.Assert( ( pageSize & 7 ) == 0 );
Debug.Assert( null == pBt.pPage1 && null == pBt.pCursor );
pBt.pageSize = (u32)pageSize;
// freeTempSpace(pBt);
}
rc = sqlite3PagerSetPagesize( pBt.pPager, ref pBt.pageSize, nReserve );
pBt.usableSize = (u16)( pBt.pageSize - nReserve );
if ( iFix != 0 )
pBt.pageSizeFixed = true;
sqlite3BtreeLeave( p );
return rc;
}
/*
** Return the currently defined page size
*/
static int sqlite3BtreeGetPageSize( Btree p )
{
return (int)p.pBt.pageSize;
}
#if !(SQLITE_OMIT_PAGER_PRAGMAS) || !(SQLITE_OMIT_VACUUM)
/*
** Return the number of bytes of space at the end of every page that
** are intentually left unused. This is the "reserved" space that is
** sometimes used by extensions.
*/
static int sqlite3BtreeGetReserve( Btree p )
{
int n;
sqlite3BtreeEnter( p );
n = (int)( p.pBt.pageSize - p.pBt.usableSize );
sqlite3BtreeLeave( p );
return n;
}
/*
** Set the maximum page count for a database if mxPage is positive.
** No changes are made if mxPage is 0 or negative.
** Regardless of the value of mxPage, return the maximum page count.
*/
static Pgno sqlite3BtreeMaxPageCount( Btree p, int mxPage )
{
Pgno n;
sqlite3BtreeEnter( p );
n = sqlite3PagerMaxPageCount( p.pBt.pPager, mxPage );
sqlite3BtreeLeave( p );
return n;
}
/*
** Set the secureDelete flag if newFlag is 0 or 1. If newFlag is -1,
** then make no changes. Always return the value of the secureDelete
** setting after the change.
*/
static int sqlite3BtreeSecureDelete( Btree p, int newFlag )
{
int b;
if ( p == null )
return 0;
sqlite3BtreeEnter( p );
if ( newFlag >= 0 )
{
p.pBt.secureDelete = ( newFlag != 0 );
}
b = p.pBt.secureDelete ? 1 : 0;
sqlite3BtreeLeave( p );
return b;
}
#endif //* !(SQLITE_OMIT_PAGER_PRAGMAS) || !(SQLITE_OMIT_VACUUM) */
/*
** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
** parameter is non-zero, then auto-vacuum mode is enabled. If zero, it
** is disabled. The default value for the auto-vacuum property is
** determined by the SQLITE_DEFAULT_AUTOVACUUM macro.
*/
static int sqlite3BtreeSetAutoVacuum( Btree p, int autoVacuum )
{
#if SQLITE_OMIT_AUTOVACUUM
return SQLITE_READONLY;
#else
BtShared pBt = p.pBt;
int rc = SQLITE_OK;
u8 av = (u8)autoVacuum;
sqlite3BtreeEnter( p );
if ( pBt.pageSizeFixed && ( av != 0 ) != pBt.autoVacuum )
{
rc = SQLITE_READONLY;
}
else
{
pBt.autoVacuum = av != 0;
pBt.incrVacuum = av == 2;
}
sqlite3BtreeLeave( p );
return rc;
#endif
}
/*
** Return the value of the 'auto-vacuum' property. If auto-vacuum is
** enabled 1 is returned. Otherwise 0.
*/
static int sqlite3BtreeGetAutoVacuum( Btree p )
{
#if SQLITE_OMIT_AUTOVACUUM
return BTREE_AUTOVACUUM_NONE;
#else
int rc;
sqlite3BtreeEnter( p );
rc = (
( !p.pBt.autoVacuum ) ? BTREE_AUTOVACUUM_NONE :
( !p.pBt.incrVacuum ) ? BTREE_AUTOVACUUM_FULL :
BTREE_AUTOVACUUM_INCR
);
sqlite3BtreeLeave( p );
return rc;
#endif
}
/*
** Get a reference to pPage1 of the database file. This will
** also acquire a readlock on that file.
**
** SQLITE_OK is returned on success. If the file is not a
** well-formed database file, then SQLITE_CORRUPT is returned.
** SQLITE_BUSY is returned if the database is locked. SQLITE_NOMEM
** is returned if we run out of memory.
*/
static int lockBtree( BtShared pBt )
{
int rc; /* Result code from subfunctions */
MemPage pPage1 = null; /* Page 1 of the database file */
Pgno nPage; /* Number of pages in the database */
Pgno nPageFile = 0; /* Number of pages in the database file */
////Pgno nPageHeader; /* Number of pages in the database according to hdr */
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( pBt.pPage1 == null );
rc = sqlite3PagerSharedLock( pBt.pPager );
if ( rc != SQLITE_OK )
return rc;
rc = btreeGetPage( pBt, 1, ref pPage1, 0 );
if ( rc != SQLITE_OK )
return rc;
/* Do some checking to help insure the file we opened really is
** a valid database file.
*/
nPage = sqlite3Get4byte( pPage1.aData, 28 );//get4byte(28+(u8*)pPage1->aData);
////nPageHeader = nPage;
sqlite3PagerPagecount( pBt.pPager, out nPageFile );
if ( nPage == 0 || memcmp( pPage1.aData, 24, pPage1.aData, 92, 4 ) != 0 )//memcmp(24 + (u8*)pPage1.aData, 92 + (u8*)pPage1.aData, 4) != 0)
{
nPage = nPageFile;
}
if ( nPage > 0 )
{
u32 pageSize;
u32 usableSize;
u8[] page1 = pPage1.aData;
rc = SQLITE_NOTADB;
if ( memcmp( page1, zMagicHeader, 16 ) != 0 )
{
goto page1_init_failed;
}
#if SQLITE_OMIT_WAL
if ( page1[18] > 1 )
{
pBt.readOnly = true;
}
if ( page1[19] > 1 )
{
pBt.pSchema.file_format = page1[19];
goto page1_init_failed;
}
#else
if( page1[18]>2 ){
pBt.readOnly = true;
}
if( page1[19]>2 ){
goto page1_init_failed;
}
/* If the write version is set to 2, this database should be accessed
** in WAL mode. If the log is not already open, open it now. Then
** return SQLITE_OK and return without populating BtShared.pPage1.
** The caller detects this and calls this function again. This is
** required as the version of page 1 currently in the page1 buffer
** may not be the latest version - there may be a newer one in the log
** file.
*/
if( page1[19]==2 && pBt.doNotUseWAL==false ){
int isOpen = 0;
rc = sqlite3PagerOpenWal(pBt.pPager, ref isOpen);
if( rc!=SQLITE_OK ){
goto page1_init_failed;
}else if( isOpen==0 ){
releasePage(pPage1);
return SQLITE_OK;
}
rc = SQLITE_NOTADB;
}
#endif
/* The maximum embedded fraction must be exactly 25%. And the minimum
** embedded fraction must be 12.5% for both leaf-data and non-leaf-data.
** The original design allowed these amounts to vary, but as of
** version 3.6.0, we require them to be fixed.
*/
if ( memcmp( page1, 21, "\x0040\x0020\x0020", 3 ) != 0 )// "\100\040\040"
{
goto page1_init_failed;
}
pageSize = (u32)( ( page1[16] << 8 ) | ( page1[17] << 16 ) );
if ( ( ( pageSize - 1 ) & pageSize ) != 0
|| pageSize > SQLITE_MAX_PAGE_SIZE
|| pageSize <= 256
)
{
goto page1_init_failed;
}
Debug.Assert( ( pageSize & 7 ) == 0 );
usableSize = pageSize - page1[20];
if ( pageSize != pBt.pageSize )
{
/* After reading the first page of the database assuming a page size
** of BtShared.pageSize, we have discovered that the page-size is
** actually pageSize. Unlock the database, leave pBt.pPage1 at
** zero and return SQLITE_OK. The caller will call this function
** again with the correct page-size.
*/
releasePage( pPage1 );
pBt.usableSize = usableSize;
pBt.pageSize = pageSize;
// freeTempSpace(pBt);
rc = sqlite3PagerSetPagesize( pBt.pPager, ref pBt.pageSize,
(int)( pageSize - usableSize ) );
return rc;
}
if ( ( pBt.db.flags & SQLITE_RecoveryMode ) == 0 && nPage > nPageFile )
{
rc = SQLITE_CORRUPT_BKPT();
goto page1_init_failed;
}
if ( usableSize < 480 )
{
goto page1_init_failed;
}
pBt.pageSize = pageSize;
pBt.usableSize = usableSize;
#if !SQLITE_OMIT_AUTOVACUUM
pBt.autoVacuum = ( sqlite3Get4byte( page1, 36 + 4 * 4 ) != 0 );
pBt.incrVacuum = ( sqlite3Get4byte( page1, 36 + 7 * 4 ) != 0 );
#endif
}
/* maxLocal is the maximum amount of payload to store locally for
** a cell. Make sure it is small enough so that at least minFanout
** cells can will fit on one page. We assume a 10-byte page header.
** Besides the payload, the cell must store:
** 2-byte pointer to the cell
** 4-byte child pointer
** 9-byte nKey value
** 4-byte nData value
** 4-byte overflow page pointer
** So a cell consists of a 2-byte pointer, a header which is as much as
** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
** page pointer.
*/
pBt.maxLocal = (u16)( ( pBt.usableSize - 12 ) * 64 / 255 - 23 );
pBt.minLocal = (u16)( ( pBt.usableSize - 12 ) * 32 / 255 - 23 );
pBt.maxLeaf = (u16)( pBt.usableSize - 35 );
pBt.minLeaf = (u16)( ( pBt.usableSize - 12 ) * 32 / 255 - 23 );
Debug.Assert( pBt.maxLeaf + 23 <= MX_CELL_SIZE( pBt ) );
pBt.pPage1 = pPage1;
pBt.nPage = nPage;
return SQLITE_OK;
page1_init_failed:
releasePage( pPage1 );
pBt.pPage1 = null;
return rc;
}
/*
** If there are no outstanding cursors and we are not in the middle
** of a transaction but there is a read lock on the database, then
** this routine unrefs the first page of the database file which
** has the effect of releasing the read lock.
**
** If there is a transaction in progress, this routine is a no-op.
*/
static void unlockBtreeIfUnused( BtShared pBt )
{
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( pBt.pCursor == null || pBt.inTransaction > TRANS_NONE );
if ( pBt.inTransaction == TRANS_NONE && pBt.pPage1 != null )
{
Debug.Assert( pBt.pPage1.aData != null );
//Debug.Assert( sqlite3PagerRefcount( pBt.pPager ) == 1 );
releasePage( pBt.pPage1 );
pBt.pPage1 = null;
}
}
/*
** If pBt points to an empty file then convert that empty file
** into a new empty database by initializing the first page of
** the database.
*/
static int newDatabase( BtShared pBt )
{
MemPage pP1;
byte[] data;
int rc;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
if ( pBt.nPage > 0 )
{
return SQLITE_OK;
}
pP1 = pBt.pPage1;
Debug.Assert( pP1 != null );
data = pP1.aData;
rc = sqlite3PagerWrite( pP1.pDbPage );
if ( rc != 0 )
return rc;
Buffer.BlockCopy( zMagicHeader, 0, data, 0, 16 );// memcpy(data, zMagicHeader, sizeof(zMagicHeader));
Debug.Assert( zMagicHeader.Length == 16 );
data[16] = (u8)( ( pBt.pageSize >> 8 ) & 0xff );
data[17] = (u8)( ( pBt.pageSize >> 16 ) & 0xff );
data[18] = 1;
data[19] = 1;
Debug.Assert( pBt.usableSize <= pBt.pageSize && pBt.usableSize + 255 >= pBt.pageSize );
data[20] = (u8)( pBt.pageSize - pBt.usableSize );
data[21] = 64;
data[22] = 32;
data[23] = 32;
//memset(&data[24], 0, 100-24);
zeroPage( pP1, PTF_INTKEY | PTF_LEAF | PTF_LEAFDATA );
pBt.pageSizeFixed = true;
#if !SQLITE_OMIT_AUTOVACUUM
Debug.Assert( pBt.autoVacuum == true || pBt.autoVacuum == false );
Debug.Assert( pBt.incrVacuum == true || pBt.incrVacuum == false );
sqlite3Put4byte( data, 36 + 4 * 4, pBt.autoVacuum ? 1 : 0 );
sqlite3Put4byte( data, 36 + 7 * 4, pBt.incrVacuum ? 1 : 0 );
#endif
pBt.nPage = 1;
data[31] = 1;
return SQLITE_OK;
}
/*
** Attempt to start a new transaction. A write-transaction
** is started if the second argument is nonzero, otherwise a read-
** transaction. If the second argument is 2 or more and exclusive
** transaction is started, meaning that no other process is allowed
** to access the database. A preexisting transaction may not be
** upgraded to exclusive by calling this routine a second time - the
** exclusivity flag only works for a new transaction.
**
** A write-transaction must be started before attempting any
** changes to the database. None of the following routines
** will work unless a transaction is started first:
**
** sqlite3BtreeCreateTable()
** sqlite3BtreeCreateIndex()
** sqlite3BtreeClearTable()
** sqlite3BtreeDropTable()
** sqlite3BtreeInsert()
** sqlite3BtreeDelete()
** sqlite3BtreeUpdateMeta()
**
** If an initial attempt to acquire the lock fails because of lock contention
** and the database was previously unlocked, then invoke the busy handler
** if there is one. But if there was previously a read-lock, do not
** invoke the busy handler - just return SQLITE_BUSY. SQLITE_BUSY is
** returned when there is already a read-lock in order to avoid a deadlock.
**
** Suppose there are two processes A and B. A has a read lock and B has
** a reserved lock. B tries to promote to exclusive but is blocked because
** of A's read lock. A tries to promote to reserved but is blocked by B.
** One or the other of the two processes must give way or there can be
** no progress. By returning SQLITE_BUSY and not invoking the busy callback
** when A already has a read lock, we encourage A to give up and let B
** proceed.
*/
static int sqlite3BtreeBeginTrans( Btree p, int wrflag )
{
BtShared pBt = p.pBt;
int rc = SQLITE_OK;
sqlite3BtreeEnter( p );
btreeIntegrity( p );
/* If the btree is already in a write-transaction, or it
** is already in a read-transaction and a read-transaction
** is requested, this is a no-op.
*/
if ( p.inTrans == TRANS_WRITE || ( p.inTrans == TRANS_READ && 0 == wrflag ) )
{
goto trans_begun;
}
/* Write transactions are not possible on a read-only database */
if ( pBt.readOnly && wrflag != 0 )
{
rc = SQLITE_READONLY;
goto trans_begun;
}
#if !SQLITE_OMIT_SHARED_CACHE
/* If another database handle has already opened a write transaction
** on this shared-btree structure and a second write transaction is
** requested, return SQLITE_LOCKED.
*/
if( (wrflag && pBt.inTransaction==TRANS_WRITE) || pBt.isPending ){
sqlite3 pBlock = pBt.pWriter.db;
}else if( wrflag>1 ){
BtLock pIter;
for(pIter=pBt.pLock; pIter; pIter=pIter.pNext){
if( pIter.pBtree!=p ){
pBlock = pIter.pBtree.db;
break;
}
}
}
if( pBlock ){
sqlite3ConnectionBlocked(p.db, pBlock);
rc = SQLITE_LOCKED_SHAREDCACHE;
goto trans_begun;
}
#endif
/* Any read-only or read-write transaction implies a read-lock on
** page 1. So if some other shared-cache client already has a write-lock
** on page 1, the transaction cannot be opened. */
rc = querySharedCacheTableLock( p, MASTER_ROOT, READ_LOCK );
if ( SQLITE_OK != rc )
goto trans_begun;
pBt.initiallyEmpty = pBt.nPage == 0;
do
{
/* Call lockBtree() until either pBt.pPage1 is populated or
** lockBtree() returns something other than SQLITE_OK. lockBtree()
** may return SQLITE_OK but leave pBt.pPage1 set to 0 if after
** reading page 1 it discovers that the page-size of the database
** file is not pBt.pageSize. In this case lockBtree() will update
** pBt.pageSize to the page-size of the file on disk.
*/
while ( pBt.pPage1 == null && SQLITE_OK == ( rc = lockBtree( pBt ) ) )
;
if ( rc == SQLITE_OK && wrflag != 0 )
{
if ( pBt.readOnly )
{
rc = SQLITE_READONLY;
}
else
{
rc = sqlite3PagerBegin( pBt.pPager, wrflag > 1, sqlite3TempInMemory( p.db ) ? 1 : 0 );
if ( rc == SQLITE_OK )
{
rc = newDatabase( pBt );
}
}
}
if ( rc != SQLITE_OK )
{
unlockBtreeIfUnused( pBt );
}
} while ( ( rc & 0xFF ) == SQLITE_BUSY && pBt.inTransaction == TRANS_NONE &&
btreeInvokeBusyHandler( pBt ) != 0 );
if ( rc == SQLITE_OK )
{
if ( p.inTrans == TRANS_NONE )
{
pBt.nTransaction++;
#if !SQLITE_OMIT_SHARED_CACHE
if( p.sharable ){
Debug.Assert( p.lock.pBtree==p && p.lock.iTable==1 );
p.lock.eLock = READ_LOCK;
p.lock.pNext = pBt.pLock;
pBt.pLock = &p.lock;
}
#endif
}
p.inTrans = ( wrflag != 0 ? TRANS_WRITE : TRANS_READ );
if ( p.inTrans > pBt.inTransaction )
{
pBt.inTransaction = p.inTrans;
}
if ( wrflag != 0 )
{
MemPage pPage1 = pBt.pPage1;
#if !SQLITE_OMIT_SHARED_CACHE
Debug.Assert( !pBt.pWriter );
pBt.pWriter = p;
pBt.isExclusive = (u8)(wrflag>1);
#endif
/* If the db-size header field is incorrect (as it may be if an old
** client has been writing the database file), update it now. Doing
** this sooner rather than later means the database size can safely
** re-read the database size from page 1 if a savepoint or transaction
** rollback occurs within the transaction.
*/
if ( pBt.nPage != sqlite3Get4byte( pPage1.aData, 28 ) )
{
rc = sqlite3PagerWrite( pPage1.pDbPage );
if ( rc == SQLITE_OK )
{
sqlite3Put4byte( pPage1.aData, (u32)28, pBt.nPage );
}
}
}
}
trans_begun:
if ( rc == SQLITE_OK && wrflag != 0 )
{
/* This call makes sure that the pager has the correct number of
** open savepoints. If the second parameter is greater than 0 and
** the sub-journal is not already open, then it will be opened here.
*/
rc = sqlite3PagerOpenSavepoint( pBt.pPager, p.db.nSavepoint );
}
btreeIntegrity( p );
sqlite3BtreeLeave( p );
return rc;
}
#if !SQLITE_OMIT_AUTOVACUUM
/*
** Set the pointer-map entries for all children of page pPage. Also, if
** pPage contains cells that point to overflow pages, set the pointer
** map entries for the overflow pages as well.
*/
static int setChildPtrmaps( MemPage pPage )
{
int i; /* Counter variable */
int nCell; /* Number of cells in page pPage */
int rc; /* Return code */
BtShared pBt = pPage.pBt;
u8 isInitOrig = pPage.isInit;
Pgno pgno = pPage.pgno;
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
rc = btreeInitPage( pPage );
if ( rc != SQLITE_OK )
{
goto set_child_ptrmaps_out;
}
nCell = pPage.nCell;
for ( i = 0; i < nCell; i++ )
{
int pCell = findCell( pPage, i );
ptrmapPutOvflPtr( pPage, pCell, ref rc );
if ( 0 == pPage.leaf )
{
Pgno childPgno = sqlite3Get4byte( pPage.aData, pCell );
ptrmapPut( pBt, childPgno, PTRMAP_BTREE, pgno, ref rc );
}
}
if ( 0 == pPage.leaf )
{
Pgno childPgno = sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 );
ptrmapPut( pBt, childPgno, PTRMAP_BTREE, pgno, ref rc );
}
set_child_ptrmaps_out:
pPage.isInit = isInitOrig;
return rc;
}
/*
** Somewhere on pPage is a pointer to page iFrom. Modify this pointer so
** that it points to iTo. Parameter eType describes the type of pointer to
** be modified, as follows:
**
** PTRMAP_BTREE: pPage is a btree-page. The pointer points at a child
** page of pPage.
**
** PTRMAP_OVERFLOW1: pPage is a btree-page. The pointer points at an overflow
** page pointed to by one of the cells on pPage.
**
** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
** overflow page in the list.
*/
static int modifyPagePointer( MemPage pPage, Pgno iFrom, Pgno iTo, u8 eType )
{
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
if ( eType == PTRMAP_OVERFLOW2 )
{
/* The pointer is always the first 4 bytes of the page in this case. */
if ( sqlite3Get4byte( pPage.aData ) != iFrom )
{
return SQLITE_CORRUPT_BKPT();
}
sqlite3Put4byte( pPage.aData, iTo );
}
else
{
u8 isInitOrig = pPage.isInit;
int i;
int nCell;
btreeInitPage( pPage );
nCell = pPage.nCell;
for ( i = 0; i < nCell; i++ )
{
int pCell = findCell( pPage, i );
if ( eType == PTRMAP_OVERFLOW1 )
{
CellInfo info = new CellInfo();
btreeParseCellPtr( pPage, pCell, ref info );
if ( info.iOverflow != 0 )
{
if ( iFrom == sqlite3Get4byte( pPage.aData, pCell, info.iOverflow ) )
{
sqlite3Put4byte( pPage.aData, pCell + info.iOverflow, (int)iTo );
break;
}
}
}
else
{
if ( sqlite3Get4byte( pPage.aData, pCell ) == iFrom )
{
sqlite3Put4byte( pPage.aData, pCell, (int)iTo );
break;
}
}
}
if ( i == nCell )
{
if ( eType != PTRMAP_BTREE ||
sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 ) != iFrom )
{
return SQLITE_CORRUPT_BKPT();
}
sqlite3Put4byte( pPage.aData, pPage.hdrOffset + 8, iTo );
}
pPage.isInit = isInitOrig;
}
return SQLITE_OK;
}
/*
** Move the open database page pDbPage to location iFreePage in the
** database. The pDbPage reference remains valid.
**
** The isCommit flag indicates that there is no need to remember that
** the journal needs to be sync()ed before database page pDbPage.pgno
** can be written to. The caller has already promised not to write to that
** page.
*/
static int relocatePage(
BtShared pBt, /* Btree */
MemPage pDbPage, /* Open page to move */
u8 eType, /* Pointer map 'type' entry for pDbPage */
Pgno iPtrPage, /* Pointer map 'page-no' entry for pDbPage */
Pgno iFreePage, /* The location to move pDbPage to */
int isCommit /* isCommit flag passed to sqlite3PagerMovepage */
)
{
MemPage pPtrPage = new MemPage(); /* The page that contains a pointer to pDbPage */
Pgno iDbPage = pDbPage.pgno;
Pager pPager = pBt.pPager;
int rc;
Debug.Assert( eType == PTRMAP_OVERFLOW2 || eType == PTRMAP_OVERFLOW1 ||
eType == PTRMAP_BTREE || eType == PTRMAP_ROOTPAGE );
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( pDbPage.pBt == pBt );
/* Move page iDbPage from its current location to page number iFreePage */
TRACE( "AUTOVACUUM: Moving %d to free page %d (ptr page %d type %d)\n",
iDbPage, iFreePage, iPtrPage, eType );
rc = sqlite3PagerMovepage( pPager, pDbPage.pDbPage, iFreePage, isCommit );
if ( rc != SQLITE_OK )
{
return rc;
}
pDbPage.pgno = iFreePage;
/* If pDbPage was a btree-page, then it may have child pages and/or cells
** that point to overflow pages. The pointer map entries for all these
** pages need to be changed.
**
** If pDbPage is an overflow page, then the first 4 bytes may store a
** pointer to a subsequent overflow page. If this is the case, then
** the pointer map needs to be updated for the subsequent overflow page.
*/
if ( eType == PTRMAP_BTREE || eType == PTRMAP_ROOTPAGE )
{
rc = setChildPtrmaps( pDbPage );
if ( rc != SQLITE_OK )
{
return rc;
}
}
else
{
Pgno nextOvfl = sqlite3Get4byte( pDbPage.aData );
if ( nextOvfl != 0 )
{
ptrmapPut( pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage, ref rc );
if ( rc != SQLITE_OK )
{
return rc;
}
}
}
/* Fix the database pointer on page iPtrPage that pointed at iDbPage so
** that it points at iFreePage. Also fix the pointer map entry for
** iPtrPage.
*/
if ( eType != PTRMAP_ROOTPAGE )
{
rc = btreeGetPage( pBt, iPtrPage, ref pPtrPage, 0 );
if ( rc != SQLITE_OK )
{
return rc;
}
rc = sqlite3PagerWrite( pPtrPage.pDbPage );
if ( rc != SQLITE_OK )
{
releasePage( pPtrPage );
return rc;
}
rc = modifyPagePointer( pPtrPage, iDbPage, iFreePage, eType );
releasePage( pPtrPage );
if ( rc == SQLITE_OK )
{
ptrmapPut( pBt, iFreePage, eType, iPtrPage, ref rc );
}
}
return rc;
}
/* Forward declaration required by incrVacuumStep(). */
//static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);
/*
** Perform a single step of an incremental-vacuum. If successful,
** return SQLITE_OK. If there is no work to do (and therefore no
** point in calling this function again), return SQLITE_DONE.
**
** More specificly, this function attempts to re-organize the
** database so that the last page of the file currently in use
** is no longer in use.
**
** If the nFin parameter is non-zero, this function assumes
** that the caller will keep calling incrVacuumStep() until
** it returns SQLITE_DONE or an error, and that nFin is the
** number of pages the database file will contain after this
** process is complete. If nFin is zero, it is assumed that
** incrVacuumStep() will be called a finite amount of times
** which may or may not empty the freelist. A full autovacuum
** has nFin>0. A "PRAGMA incremental_vacuum" has nFin==null.
*/
static int incrVacuumStep( BtShared pBt, Pgno nFin, Pgno iLastPg )
{
Pgno nFreeList; /* Number of pages still on the free-list */
int rc;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( iLastPg > nFin );
if ( !PTRMAP_ISPAGE( pBt, iLastPg ) && iLastPg != PENDING_BYTE_PAGE( pBt ) )
{
u8 eType = 0;
Pgno iPtrPage = 0;
nFreeList = sqlite3Get4byte( pBt.pPage1.aData, 36 );
if ( nFreeList == 0 )
{
return SQLITE_DONE;
}
rc = ptrmapGet( pBt, iLastPg, ref eType, ref iPtrPage );
if ( rc != SQLITE_OK )
{
return rc;
}
if ( eType == PTRMAP_ROOTPAGE )
{
return SQLITE_CORRUPT_BKPT();
}
if ( eType == PTRMAP_FREEPAGE )
{
if ( nFin == 0 )
{
/* Remove the page from the files free-list. This is not required
** if nFin is non-zero. In that case, the free-list will be
** truncated to zero after this function returns, so it doesn't
** matter if it still contains some garbage entries.
*/
Pgno iFreePg = 0;
MemPage pFreePg = new MemPage();
rc = allocateBtreePage( pBt, ref pFreePg, ref iFreePg, iLastPg, 1 );
if ( rc != SQLITE_OK )
{
return rc;
}
Debug.Assert( iFreePg == iLastPg );
releasePage( pFreePg );
}
}
else
{
Pgno iFreePg = 0; /* Index of free page to move pLastPg to */
MemPage pLastPg = new MemPage();
rc = btreeGetPage( pBt, iLastPg, ref pLastPg, 0 );
if ( rc != SQLITE_OK )
{
return rc;
}
/* If nFin is zero, this loop runs exactly once and page pLastPg
** is swapped with the first free page pulled off the free list.
**
** On the other hand, if nFin is greater than zero, then keep
** looping until a free-page located within the first nFin pages
** of the file is found.
*/
do
{
MemPage pFreePg = new MemPage();
rc = allocateBtreePage( pBt, ref pFreePg, ref iFreePg, 0, 0 );
if ( rc != SQLITE_OK )
{
releasePage( pLastPg );
return rc;
}
releasePage( pFreePg );
} while ( nFin != 0 && iFreePg > nFin );
Debug.Assert( iFreePg < iLastPg );
rc = sqlite3PagerWrite( pLastPg.pDbPage );
if ( rc == SQLITE_OK )
{
rc = relocatePage( pBt, pLastPg, eType, iPtrPage, iFreePg, ( nFin != 0 ) ? 1 : 0 );
}
releasePage( pLastPg );
if ( rc != SQLITE_OK )
{
return rc;
}
}
}
if ( nFin == 0 )
{
iLastPg--;
while ( iLastPg == PENDING_BYTE_PAGE( pBt ) || PTRMAP_ISPAGE( pBt, iLastPg ) )
{
if ( PTRMAP_ISPAGE( pBt, iLastPg ) )
{
MemPage pPg = new MemPage();
rc = btreeGetPage( pBt, iLastPg, ref pPg, 0 );
if ( rc != SQLITE_OK )
{
return rc;
}
rc = sqlite3PagerWrite( pPg.pDbPage );
releasePage( pPg );
if ( rc != SQLITE_OK )
{
return rc;
}
}
iLastPg--;
}
sqlite3PagerTruncateImage( pBt.pPager, iLastPg );
pBt.nPage = iLastPg;
}
return SQLITE_OK;
}
/*
** A write-transaction must be opened before calling this function.
** It performs a single unit of work towards an incremental vacuum.
**
** If the incremental vacuum is finished after this function has run,
** SQLITE_DONE is returned. If it is not finished, but no error occurred,
** SQLITE_OK is returned. Otherwise an SQLite error code.
*/
static int sqlite3BtreeIncrVacuum( Btree p )
{
int rc;
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
Debug.Assert( pBt.inTransaction == TRANS_WRITE && p.inTrans == TRANS_WRITE );
if ( !pBt.autoVacuum )
{
rc = SQLITE_DONE;
}
else
{
invalidateAllOverflowCache( pBt );
rc = incrVacuumStep( pBt, 0, btreePagecount( pBt ) );
if ( rc == SQLITE_OK )
{
rc = sqlite3PagerWrite( pBt.pPage1.pDbPage );
sqlite3Put4byte( pBt.pPage1.aData, (u32)28, pBt.nPage );//put4byte(&pBt->pPage1->aData[28], pBt->nPage);
}
}
sqlite3BtreeLeave( p );
return rc;
}
/*
** This routine is called prior to sqlite3PagerCommit when a transaction
** is commited for an auto-vacuum database.
**
** If SQLITE_OK is returned, then pnTrunc is set to the number of pages
** the database file should be truncated to during the commit process.
** i.e. the database has been reorganized so that only the first pnTrunc
** pages are in use.
*/
static int autoVacuumCommit( BtShared pBt )
{
int rc = SQLITE_OK;
Pager pPager = pBt.pPager;
// VVA_ONLY( int nRef = sqlite3PagerRefcount(pPager) );
#if !NDEBUG || DEBUG
int nRef = sqlite3PagerRefcount( pPager );
#else
int nRef=0;
#endif
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
invalidateAllOverflowCache( pBt );
Debug.Assert( pBt.autoVacuum );
if ( !pBt.incrVacuum )
{
Pgno nFin; /* Number of pages in database after autovacuuming */
Pgno nFree; /* Number of pages on the freelist initially */
Pgno nPtrmap; /* Number of PtrMap pages to be freed */
Pgno iFree; /* The next page to be freed */
int nEntry; /* Number of entries on one ptrmap page */
Pgno nOrig; /* Database size before freeing */
nOrig = btreePagecount( pBt );
if ( PTRMAP_ISPAGE( pBt, nOrig ) || nOrig == PENDING_BYTE_PAGE( pBt ) )
{
/* It is not possible to create a database for which the final page
** is either a pointer-map page or the pending-byte page. If one
** is encountered, this indicates corruption.
*/
return SQLITE_CORRUPT_BKPT();
}
nFree = sqlite3Get4byte( pBt.pPage1.aData, 36 );
nEntry = (int)pBt.usableSize / 5;
nPtrmap = (Pgno)( ( nFree - nOrig + PTRMAP_PAGENO( pBt, nOrig ) + (Pgno)nEntry ) / nEntry );
nFin = nOrig - nFree - nPtrmap;
if ( nOrig > PENDING_BYTE_PAGE( pBt ) && nFin < PENDING_BYTE_PAGE( pBt ) )
{
nFin--;
}
while ( PTRMAP_ISPAGE( pBt, nFin ) || nFin == PENDING_BYTE_PAGE( pBt ) )
{
nFin--;
}
if ( nFin > nOrig )
return SQLITE_CORRUPT_BKPT();
for ( iFree = nOrig; iFree > nFin && rc == SQLITE_OK; iFree-- )
{
rc = incrVacuumStep( pBt, nFin, iFree );
}
if ( ( rc == SQLITE_DONE || rc == SQLITE_OK ) && nFree > 0 )
{
rc = sqlite3PagerWrite( pBt.pPage1.pDbPage );
sqlite3Put4byte( pBt.pPage1.aData, 32, 0 );
sqlite3Put4byte( pBt.pPage1.aData, 36, 0 );
sqlite3Put4byte( pBt.pPage1.aData, (u32)28, nFin );
sqlite3PagerTruncateImage( pBt.pPager, nFin );
pBt.nPage = nFin;
}
if ( rc != SQLITE_OK )
{
sqlite3PagerRollback( pPager );
}
}
Debug.Assert( nRef == sqlite3PagerRefcount( pPager ) );
return rc;
}
#else //* ifndef SQLITE_OMIT_AUTOVACUUM */
//# define setChildPtrmaps(x) SQLITE_OK
#endif
/*
** This routine does the first phase of a two-phase commit. This routine
** causes a rollback journal to be created (if it does not already exist)
** and populated with enough information so that if a power loss occurs
** the database can be restored to its original state by playing back
** the journal. Then the contents of the journal are flushed out to
** the disk. After the journal is safely on oxide, the changes to the
** database are written into the database file and flushed to oxide.
** At the end of this call, the rollback journal still exists on the
** disk and we are still holding all locks, so the transaction has not
** committed. See sqlite3BtreeCommitPhaseTwo() for the second phase of the
** commit process.
**
** This call is a no-op if no write-transaction is currently active on pBt.
**
** Otherwise, sync the database file for the btree pBt. zMaster points to
** the name of a master journal file that should be written into the
** individual journal file, or is NULL, indicating no master journal file
** (single database transaction).
**
** When this is called, the master journal should already have been
** created, populated with this journal pointer and synced to disk.
**
** Once this is routine has returned, the only thing required to commit
** the write-transaction for this database file is to delete the journal.
*/
static int sqlite3BtreeCommitPhaseOne( Btree p, string zMaster )
{
int rc = SQLITE_OK;
if ( p.inTrans == TRANS_WRITE )
{
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pBt.autoVacuum )
{
rc = autoVacuumCommit( pBt );
if ( rc != SQLITE_OK )
{
sqlite3BtreeLeave( p );
return rc;
}
}
#endif
rc = sqlite3PagerCommitPhaseOne( pBt.pPager, zMaster, false );
sqlite3BtreeLeave( p );
}
return rc;
}
/*
** This function is called from both BtreeCommitPhaseTwo() and BtreeRollback()
** at the conclusion of a transaction.
*/
static void btreeEndTransaction( Btree p )
{
BtShared pBt = p.pBt;
Debug.Assert( sqlite3BtreeHoldsMutex( p ) );
btreeClearHasContent( pBt );
if ( p.inTrans > TRANS_NONE && p.db.activeVdbeCnt > 1 )
{
/* If there are other active statements that belong to this database
** handle, downgrade to a read-only transaction. The other statements
** may still be reading from the database. */
downgradeAllSharedCacheTableLocks( p );
p.inTrans = TRANS_READ;
}
else
{
/* If the handle had any kind of transaction open, decrement the
** transaction count of the shared btree. If the transaction count
** reaches 0, set the shared state to TRANS_NONE. The unlockBtreeIfUnused()
** call below will unlock the pager. */
if ( p.inTrans != TRANS_NONE )
{
clearAllSharedCacheTableLocks( p );
pBt.nTransaction--;
if ( 0 == pBt.nTransaction )
{
pBt.inTransaction = TRANS_NONE;
}
}
/* Set the current transaction state to TRANS_NONE and unlock the
** pager if this call closed the only read or write transaction. */
p.inTrans = TRANS_NONE;
unlockBtreeIfUnused( pBt );
}
btreeIntegrity( p );
}
/*
** Commit the transaction currently in progress.
**
** This routine implements the second phase of a 2-phase commit. The
** sqlite3BtreeCommitPhaseOne() routine does the first phase and should
** be invoked prior to calling this routine. The sqlite3BtreeCommitPhaseOne()
** routine did all the work of writing information out to disk and flushing the
** contents so that they are written onto the disk platter. All this
** routine has to do is delete or truncate or zero the header in the
** the rollback journal (which causes the transaction to commit) and
** drop locks.
**
** Normally, if an error occurs while the pager layer is attempting to
** finalize the underlying journal file, this function returns an error and
** the upper layer will attempt a rollback. However, if the second argument
** is non-zero then this b-tree transaction is part of a multi-file
** transaction. In this case, the transaction has already been committed
** (by deleting a master journal file) and the caller will ignore this
** functions return code. So, even if an error occurs in the pager layer,
** reset the b-tree objects internal state to indicate that the write
** transaction has been closed. This is quite safe, as the pager will have
** transitioned to the error state.
**
** This will release the write lock on the database file. If there
** are no active cursors, it also releases the read lock.
*/
static int sqlite3BtreeCommitPhaseTwo( Btree p, int bCleanup)
{
if ( p.inTrans == TRANS_NONE )
return SQLITE_OK;
sqlite3BtreeEnter( p );
btreeIntegrity( p );
/* If the handle has a write-transaction open, commit the shared-btrees
** transaction and set the shared state to TRANS_READ.
*/
if ( p.inTrans == TRANS_WRITE )
{
int rc;
BtShared pBt = p.pBt;
Debug.Assert( pBt.inTransaction == TRANS_WRITE );
Debug.Assert( pBt.nTransaction > 0 );
rc = sqlite3PagerCommitPhaseTwo( pBt.pPager );
if ( rc != SQLITE_OK && bCleanup == 0 )
{
sqlite3BtreeLeave( p );
return rc;
}
pBt.inTransaction = TRANS_READ;
}
btreeEndTransaction( p );
sqlite3BtreeLeave( p );
return SQLITE_OK;
}
/*
** Do both phases of a commit.
*/
static int sqlite3BtreeCommit( Btree p )
{
int rc;
sqlite3BtreeEnter( p );
rc = sqlite3BtreeCommitPhaseOne( p, null );
if ( rc == SQLITE_OK )
{
rc = sqlite3BtreeCommitPhaseTwo( p, 0 );
}
sqlite3BtreeLeave( p );
return rc;
}
#if !NDEBUG || DEBUG
/*
** Return the number of write-cursors open on this handle. This is for use
** in Debug.Assert() expressions, so it is only compiled if NDEBUG is not
** defined.
**
** For the purposes of this routine, a write-cursor is any cursor that
** is capable of writing to the databse. That means the cursor was
** originally opened for writing and the cursor has not be disabled
** by having its state changed to CURSOR_FAULT.
*/
static int countWriteCursors( BtShared pBt )
{
BtCursor pCur;
int r = 0;
for ( pCur = pBt.pCursor; pCur != null; pCur = pCur.pNext )
{
if ( pCur.wrFlag != 0 && pCur.eState != CURSOR_FAULT )
r++;
}
return r;
}
#else
static int countWriteCursors(BtShared pBt) { return -1; }
#endif
/*
** This routine sets the state to CURSOR_FAULT and the error
** code to errCode for every cursor on BtShared that pBtree
** references.
**
** Every cursor is tripped, including cursors that belong
** to other database connections that happen to be sharing
** the cache with pBtree.
**
** This routine gets called when a rollback occurs.
** All cursors using the same cache must be tripped
** to prevent them from trying to use the btree after
** the rollback. The rollback may have deleted tables
** or moved root pages, so it is not sufficient to
** save the state of the cursor. The cursor must be
** invalidated.
*/
static void sqlite3BtreeTripAllCursors( Btree pBtree, int errCode )
{
BtCursor p;
sqlite3BtreeEnter( pBtree );
for ( p = pBtree.pBt.pCursor; p != null; p = p.pNext )
{
int i;
sqlite3BtreeClearCursor( p );
p.eState = CURSOR_FAULT;
p.skipNext = errCode;
for ( i = 0; i <= p.iPage; i++ )
{
releasePage( p.apPage[i] );
p.apPage[i] = null;
}
}
sqlite3BtreeLeave( pBtree );
}
/*
** Rollback the transaction in progress. All cursors will be
** invalided by this operation. Any attempt to use a cursor
** that was open at the beginning of this operation will result
** in an error.
**
** This will release the write lock on the database file. If there
** are no active cursors, it also releases the read lock.
*/
static int sqlite3BtreeRollback( Btree p )
{
int rc;
BtShared pBt = p.pBt;
MemPage pPage1 = new MemPage();
sqlite3BtreeEnter( p );
rc = saveAllCursors( pBt, 0, null );
#if !SQLITE_OMIT_SHARED_CACHE
if( rc!=SQLITE_OK ){
/* This is a horrible situation. An IO or malloc() error occurred whilst
** trying to save cursor positions. If this is an automatic rollback (as
** the result of a constraint, malloc() failure or IO error) then
** the cache may be internally inconsistent (not contain valid trees) so
** we cannot simply return the error to the caller. Instead, abort
** all queries that may be using any of the cursors that failed to save.
*/
sqlite3BtreeTripAllCursors(p, rc);
}
#endif
btreeIntegrity( p );
if ( p.inTrans == TRANS_WRITE )
{
int rc2;
Debug.Assert( TRANS_WRITE == pBt.inTransaction );
rc2 = sqlite3PagerRollback( pBt.pPager );
if ( rc2 != SQLITE_OK )
{
rc = rc2;
}
/* The rollback may have destroyed the pPage1.aData value. So
** call btreeGetPage() on page 1 again to make
** sure pPage1.aData is set correctly. */
if ( btreeGetPage( pBt, 1, ref pPage1, 0 ) == SQLITE_OK )
{
Pgno nPage = sqlite3Get4byte( pPage1.aData, 28 );
testcase( nPage == 0 );
if ( nPage == 0 )
sqlite3PagerPagecount( pBt.pPager, out nPage );
testcase( pBt.nPage != nPage );
pBt.nPage = nPage;
releasePage( pPage1 );
}
Debug.Assert( countWriteCursors( pBt ) == 0 );
pBt.inTransaction = TRANS_READ;
}
btreeEndTransaction( p );
sqlite3BtreeLeave( p );
return rc;
}
/*
** Start a statement subtransaction. The subtransaction can can be rolled
** back independently of the main transaction. You must start a transaction
** before starting a subtransaction. The subtransaction is ended automatically
** if the main transaction commits or rolls back.
**
** Statement subtransactions are used around individual SQL statements
** that are contained within a BEGIN...COMMIT block. If a constraint
** error occurs within the statement, the effect of that one statement
** can be rolled back without having to rollback the entire transaction.
**
** A statement sub-transaction is implemented as an anonymous savepoint. The
** value passed as the second parameter is the total number of savepoints,
** including the new anonymous savepoint, open on the B-Tree. i.e. if there
** are no active savepoints and no other statement-transactions open,
** iStatement is 1. This anonymous savepoint can be released or rolled back
** using the sqlite3BtreeSavepoint() function.
*/
static int sqlite3BtreeBeginStmt( Btree p, int iStatement )
{
int rc;
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
Debug.Assert( p.inTrans == TRANS_WRITE );
Debug.Assert( !pBt.readOnly );
Debug.Assert( iStatement > 0 );
Debug.Assert( iStatement > p.db.nSavepoint );
Debug.Assert( pBt.inTransaction == TRANS_WRITE );
/* At the pager level, a statement transaction is a savepoint with
** an index greater than all savepoints created explicitly using
** SQL statements. It is illegal to open, release or rollback any
** such savepoints while the statement transaction savepoint is active.
*/
rc = sqlite3PagerOpenSavepoint( pBt.pPager, iStatement );
sqlite3BtreeLeave( p );
return rc;
}
/*
** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
** or SAVEPOINT_RELEASE. This function either releases or rolls back the
** savepoint identified by parameter iSavepoint, depending on the value
** of op.
**
** Normally, iSavepoint is greater than or equal to zero. However, if op is
** SAVEPOINT_ROLLBACK, then iSavepoint may also be -1. In this case the
** contents of the entire transaction are rolled back. This is different
** from a normal transaction rollback, as no locks are released and the
** transaction remains open.
*/
static int sqlite3BtreeSavepoint( Btree p, int op, int iSavepoint )
{
int rc = SQLITE_OK;
if ( p != null && p.inTrans == TRANS_WRITE )
{
BtShared pBt = p.pBt;
Debug.Assert( op == SAVEPOINT_RELEASE || op == SAVEPOINT_ROLLBACK );
Debug.Assert( iSavepoint >= 0 || ( iSavepoint == -1 && op == SAVEPOINT_ROLLBACK ) );
sqlite3BtreeEnter( p );
rc = sqlite3PagerSavepoint( pBt.pPager, op, iSavepoint );
if ( rc == SQLITE_OK )
{
if ( iSavepoint < 0 && pBt.initiallyEmpty )
pBt.nPage = 0;
rc = newDatabase( pBt );
pBt.nPage = sqlite3Get4byte( pBt.pPage1.aData, 28 );
/* The database size was written into the offset 28 of the header
** when the transaction started, so we know that the value at offset
** 28 is nonzero. */
Debug.Assert( pBt.nPage > 0 );
}
sqlite3BtreeLeave( p );
}
return rc;
}
/*
** Create a new cursor for the BTree whose root is on the page
** iTable. If a read-only cursor is requested, it is assumed that
** the caller already has at least a read-only transaction open
** on the database already. If a write-cursor is requested, then
** the caller is assumed to have an open write transaction.
**
** If wrFlag==null, then the cursor can only be used for reading.
** If wrFlag==1, then the cursor can be used for reading or for
** writing if other conditions for writing are also met. These
** are the conditions that must be met in order for writing to
** be allowed:
**
** 1: The cursor must have been opened with wrFlag==1
**
** 2: Other database connections that share the same pager cache
** but which are not in the READ_UNCOMMITTED state may not have
** cursors open with wrFlag==null on the same table. Otherwise
** the changes made by this write cursor would be visible to
** the read cursors in the other database connection.
**
** 3: The database must be writable (not on read-only media)
**
** 4: There must be an active transaction.
**
** No checking is done to make sure that page iTable really is the
** root page of a b-tree. If it is not, then the cursor acquired
** will not work correctly.
**
** It is assumed that the sqlite3BtreeCursorZero() has been called
** on pCur to initialize the memory space prior to invoking this routine.
*/
static int btreeCursor(
Btree p, /* The btree */
int iTable, /* Root page of table to open */
int wrFlag, /* 1 to write. 0 read-only */
KeyInfo pKeyInfo, /* First arg to comparison function */
BtCursor pCur /* Space for new cursor */
)
{
BtShared pBt = p.pBt; /* Shared b-tree handle */
Debug.Assert( sqlite3BtreeHoldsMutex( p ) );
Debug.Assert( wrFlag == 0 || wrFlag == 1 );
/* The following Debug.Assert statements verify that if this is a sharable
** b-tree database, the connection is holding the required table locks,
** and that no other connection has any open cursor that conflicts with
** this lock. */
Debug.Assert( hasSharedCacheTableLock( p, (u32)iTable, pKeyInfo != null ? 1 : 0, wrFlag + 1 ) );
Debug.Assert( wrFlag == 0 || !hasReadConflicts( p, (u32)iTable ) );
/* Assert that the caller has opened the required transaction. */
Debug.Assert( p.inTrans > TRANS_NONE );
Debug.Assert( wrFlag == 0 || p.inTrans == TRANS_WRITE );
Debug.Assert( pBt.pPage1 != null && pBt.pPage1.aData != null );
if ( NEVER( wrFlag != 0 && pBt.readOnly ) )
{
return SQLITE_READONLY;
}
if ( iTable == 1 && btreePagecount( pBt ) == 0 )
{
return SQLITE_EMPTY;
}
/* Now that no other errors can occur, finish filling in the BtCursor
** variables and link the cursor into the BtShared list. */
pCur.pgnoRoot = (Pgno)iTable;
pCur.iPage = -1;
pCur.pKeyInfo = pKeyInfo;
pCur.pBtree = p;
pCur.pBt = pBt;
pCur.wrFlag = (u8)wrFlag;
pCur.pNext = pBt.pCursor;
if ( pCur.pNext != null )
{
pCur.pNext.pPrev = pCur;
}
pBt.pCursor = pCur;
pCur.eState = CURSOR_INVALID;
pCur.cachedRowid = 0;
return SQLITE_OK;
}
static int sqlite3BtreeCursor(
Btree p, /* The btree */
int iTable, /* Root page of table to open */
int wrFlag, /* 1 to write. 0 read-only */
KeyInfo pKeyInfo, /* First arg to xCompare() */
BtCursor pCur /* Write new cursor here */
)
{
int rc;
sqlite3BtreeEnter( p );
rc = btreeCursor( p, iTable, wrFlag, pKeyInfo, pCur );
sqlite3BtreeLeave( p );
return rc;
}
/*
** Return the size of a BtCursor object in bytes.
**
** This interfaces is needed so that users of cursors can preallocate
** sufficient storage to hold a cursor. The BtCursor object is opaque
** to users so they cannot do the sizeof() themselves - they must call
** this routine.
*/
static int sqlite3BtreeCursorSize()
{
return -1; // Not Used -- return ROUND8(sizeof(BtCursor));
}
/*
** Initialize memory that will be converted into a BtCursor object.
**
** The simple approach here would be to memset() the entire object
** to zero. But it turns out that the apPage[] and aiIdx[] arrays
** do not need to be zeroed and they are large, so we can save a lot
** of run-time by skipping the initialization of those elements.
*/
static void sqlite3BtreeCursorZero( BtCursor p )
{
p.Clear(); // memset( p, 0, offsetof( BtCursor, iPage ) );
}
/*
** Set the cached rowid value of every cursor in the same database file
** as pCur and having the same root page number as pCur. The value is
** set to iRowid.
**
** Only positive rowid values are considered valid for this cache.
** The cache is initialized to zero, indicating an invalid cache.
** A btree will work fine with zero or negative rowids. We just cannot
** cache zero or negative rowids, which means tables that use zero or
** negative rowids might run a little slower. But in practice, zero
** or negative rowids are very uncommon so this should not be a problem.
*/
static void sqlite3BtreeSetCachedRowid( BtCursor pCur, sqlite3_int64 iRowid )
{
BtCursor p;
for ( p = pCur.pBt.pCursor; p != null; p = p.pNext )
{
if ( p.pgnoRoot == pCur.pgnoRoot )
p.cachedRowid = iRowid;
}
Debug.Assert( pCur.cachedRowid == iRowid );
}
/*
** Return the cached rowid for the given cursor. A negative or zero
** return value indicates that the rowid cache is invalid and should be
** ignored. If the rowid cache has never before been set, then a
** zero is returned.
*/
static sqlite3_int64 sqlite3BtreeGetCachedRowid( BtCursor pCur )
{
return pCur.cachedRowid;
}
/*
** Close a cursor. The read lock on the database file is released
** when the last cursor is closed.
*/
static int sqlite3BtreeCloseCursor( BtCursor pCur )
{
Btree pBtree = pCur.pBtree;
if ( pBtree != null )
{
int i;
BtShared pBt = pCur.pBt;
sqlite3BtreeEnter( pBtree );
sqlite3BtreeClearCursor( pCur );
if ( pCur.pPrev != null )
{
pCur.pPrev.pNext = pCur.pNext;
}
else
{
pBt.pCursor = pCur.pNext;
}
if ( pCur.pNext != null )
{
pCur.pNext.pPrev = pCur.pPrev;
}
for ( i = 0; i <= pCur.iPage; i++ )
{
releasePage( pCur.apPage[i] );
}
unlockBtreeIfUnused( pBt );
invalidateOverflowCache( pCur );
/* sqlite3_free(ref pCur); */
sqlite3BtreeLeave( pBtree );
}
return SQLITE_OK;
}
/*
** Make sure the BtCursor* given in the argument has a valid
** BtCursor.info structure. If it is not already valid, call
** btreeParseCell() to fill it in.
**
** BtCursor.info is a cache of the information in the current cell.
** Using this cache reduces the number of calls to btreeParseCell().
**
** 2007-06-25: There is a bug in some versions of MSVC that cause the
** compiler to crash when getCellInfo() is implemented as a macro.
** But there is a measureable speed advantage to using the macro on gcc
** (when less compiler optimizations like -Os or -O0 are used and the
** compiler is not doing agressive inlining.) So we use a real function
** for MSVC and a macro for everything else. Ticket #2457.
*/
#if !NDEBUG
static void assertCellInfo( BtCursor pCur )
{
CellInfo info;
int iPage = pCur.iPage;
info = new CellInfo();//memset(info, 0, sizeof(info));
btreeParseCell( pCur.apPage[iPage], pCur.aiIdx[iPage], ref info );
Debug.Assert( info.GetHashCode() == pCur.info.GetHashCode() || info.Equals( pCur.info ) );//memcmp(info, pCur.info, sizeof(info))==0 );
}
#else
// #define assertCellInfo(x)
static void assertCellInfo(BtCursor pCur) { }
#endif
////#if _MSC_VER
/* Use a real function in MSVC to work around bugs in that compiler. */
static void getCellInfo( BtCursor pCur )
{
if ( pCur.info.nSize == 0 )
{
int iPage = pCur.iPage;
btreeParseCell( pCur.apPage[iPage], pCur.aiIdx[iPage], ref pCur.info );
pCur.validNKey = true;
}
else
{
assertCellInfo( pCur );
}
}
////#else //* if not _MSC_VER */
///* Use a macro in all other compilers so that the function is inlined */
////#define getCellInfo(pCur) \
//// if( pCur.info.nSize==null ){ \
//// int iPage = pCur.iPage; \
//// btreeParseCell(pCur.apPage[iPage],pCur.aiIdx[iPage],&pCur.info); \
//// pCur.validNKey = true; \
//// }else{ \
//// assertCellInfo(pCur); \
//// }
////#endif //* _MSC_VER */
#if !NDEBUG //* The next routine used only within Debug.Assert() statements */
/*
** Return true if the given BtCursor is valid. A valid cursor is one
** that is currently pointing to a row in a (non-empty) table.
** This is a verification routine is used only within Debug.Assert() statements.
*/
static bool sqlite3BtreeCursorIsValid( BtCursor pCur )
{
return pCur != null && pCur.eState == CURSOR_VALID;
}
#else
static bool sqlite3BtreeCursorIsValid(BtCursor pCur) { return true; }
#endif //* NDEBUG */
/*
** Set pSize to the size of the buffer needed to hold the value of
** the key for the current entry. If the cursor is not pointing
** to a valid entry, pSize is set to 0.
**
** For a table with the INTKEY flag set, this routine returns the key
** itself, not the number of bytes in the key.
**
** The caller must position the cursor prior to invoking this routine.
**
** This routine cannot fail. It always returns SQLITE_OK.
*/
static int sqlite3BtreeKeySize( BtCursor pCur, ref i64 pSize )
{
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_INVALID || pCur.eState == CURSOR_VALID );
if ( pCur.eState != CURSOR_VALID )
{
pSize = 0;
}
else
{
getCellInfo( pCur );
pSize = pCur.info.nKey;
}
return SQLITE_OK;
}
/*
** Set pSize to the number of bytes of data in the entry the
** cursor currently points to.
**
** The caller must guarantee that the cursor is pointing to a non-NULL
** valid entry. In other words, the calling procedure must guarantee
** that the cursor has Cursor.eState==CURSOR_VALID.
**
** Failure is not possible. This function always returns SQLITE_OK.
** It might just as well be a procedure (returning void) but we continue
** to return an integer result code for historical reasons.
*/
static int sqlite3BtreeDataSize( BtCursor pCur, ref u32 pSize )
{
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_VALID );
getCellInfo( pCur );
pSize = pCur.info.nData;
return SQLITE_OK;
}
/*
** Given the page number of an overflow page in the database (parameter
** ovfl), this function finds the page number of the next page in the
** linked list of overflow pages. If possible, it uses the auto-vacuum
** pointer-map data instead of reading the content of page ovfl to do so.
**
** If an error occurs an SQLite error code is returned. Otherwise:
**
** The page number of the next overflow page in the linked list is
** written to pPgnoNext. If page ovfl is the last page in its linked
** list, pPgnoNext is set to zero.
**
** If ppPage is not NULL, and a reference to the MemPage object corresponding
** to page number pOvfl was obtained, then ppPage is set to point to that
** reference. It is the responsibility of the caller to call releasePage()
** on ppPage to free the reference. In no reference was obtained (because
** the pointer-map was used to obtain the value for pPgnoNext), then
** ppPage is set to zero.
*/
static int getOverflowPage(
BtShared pBt, /* The database file */
Pgno ovfl, /* Current overflow page number */
out MemPage ppPage, /* OUT: MemPage handle (may be NULL) */
out Pgno pPgnoNext /* OUT: Next overflow page number */
)
{
Pgno next = 0;
MemPage pPage = null;
ppPage = null;
int rc = SQLITE_OK;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
// Debug.Assert( pPgnoNext);
#if !SQLITE_OMIT_AUTOVACUUM
/* Try to find the next page in the overflow list using the
** autovacuum pointer-map pages. Guess that the next page in
** the overflow list is page number (ovfl+1). If that guess turns
** out to be wrong, fall back to loading the data of page
** number ovfl to determine the next page number.
*/
if ( pBt.autoVacuum )
{
Pgno pgno = 0;
Pgno iGuess = ovfl + 1;
u8 eType = 0;
while ( PTRMAP_ISPAGE( pBt, iGuess ) || iGuess == PENDING_BYTE_PAGE( pBt ) )
{
iGuess++;
}
if ( iGuess <= btreePagecount( pBt ) )
{
rc = ptrmapGet( pBt, iGuess, ref eType, ref pgno );
if ( rc == SQLITE_OK && eType == PTRMAP_OVERFLOW2 && pgno == ovfl )
{
next = iGuess;
rc = SQLITE_DONE;
}
}
}
#endif
Debug.Assert( next == 0 || rc == SQLITE_DONE );
if ( rc == SQLITE_OK )
{
rc = btreeGetPage( pBt, ovfl, ref pPage, 0 );
Debug.Assert( rc == SQLITE_OK || pPage == null );
if ( rc == SQLITE_OK )
{
next = sqlite3Get4byte( pPage.aData );
}
}
pPgnoNext = next;
if ( ppPage != null )
{
ppPage = pPage;
}
else
{
releasePage( pPage );
}
return ( rc == SQLITE_DONE ? SQLITE_OK : rc );
}
/*
** Copy data from a buffer to a page, or from a page to a buffer.
**
** pPayload is a pointer to data stored on database page pDbPage.
** If argument eOp is false, then nByte bytes of data are copied
** from pPayload to the buffer pointed at by pBuf. If eOp is true,
** then sqlite3PagerWrite() is called on pDbPage and nByte bytes
** of data are copied from the buffer pBuf to pPayload.
**
** SQLITE_OK is returned on success, otherwise an error code.
*/
static int copyPayload(
byte[] pPayload, /* Pointer to page data */
u32 payloadOffset, /* Offset into page data */
byte[] pBuf, /* Pointer to buffer */
u32 pBufOffset, /* Offset into buffer */
u32 nByte, /* Number of bytes to copy */
int eOp, /* 0 . copy from page, 1 . copy to page */
DbPage pDbPage /* Page containing pPayload */
)
{
if ( eOp != 0 )
{
/* Copy data from buffer to page (a write operation) */
int rc = sqlite3PagerWrite( pDbPage );
if ( rc != SQLITE_OK )
{
return rc;
}
Buffer.BlockCopy( pBuf, (int)pBufOffset, pPayload, (int)payloadOffset, (int)nByte );// memcpy( pPayload, pBuf, nByte );
}
else
{
/* Copy data from page to buffer (a read operation) */
Buffer.BlockCopy( pPayload, (int)payloadOffset, pBuf, (int)pBufOffset, (int)nByte );//memcpy(pBuf, pPayload, nByte);
}
return SQLITE_OK;
}
//static int copyPayload(
// byte[] pPayload, /* Pointer to page data */
// byte[] pBuf, /* Pointer to buffer */
// int nByte, /* Number of bytes to copy */
// int eOp, /* 0 -> copy from page, 1 -> copy to page */
// DbPage pDbPage /* Page containing pPayload */
//){
// if( eOp!=0 ){
// /* Copy data from buffer to page (a write operation) */
// int rc = sqlite3PagerWrite(pDbPage);
// if( rc!=SQLITE_OK ){
// return rc;
// }
// memcpy(pPayload, pBuf, nByte);
// }else{
// /* Copy data from page to buffer (a read operation) */
// memcpy(pBuf, pPayload, nByte);
// }
// return SQLITE_OK;
//}
/*
** This function is used to read or overwrite payload information
** for the entry that the pCur cursor is pointing to. If the eOp
** parameter is 0, this is a read operation (data copied into
** buffer pBuf). If it is non-zero, a write (data copied from
** buffer pBuf).
**
** A total of "amt" bytes are read or written beginning at "offset".
** Data is read to or from the buffer pBuf.
**
** The content being read or written might appear on the main page
** or be scattered out on multiple overflow pages.
**
** If the BtCursor.isIncrblobHandle flag is set, and the current
** cursor entry uses one or more overflow pages, this function
** allocates space for and lazily popluates the overflow page-list
** cache array (BtCursor.aOverflow). Subsequent calls use this
** cache to make seeking to the supplied offset more efficient.
**
** Once an overflow page-list cache has been allocated, it may be
** invalidated if some other cursor writes to the same table, or if
** the cursor is moved to a different row. Additionally, in auto-vacuum
** mode, the following events may invalidate an overflow page-list cache.
**
** * An incremental vacuum,
** * A commit in auto_vacuum="full" mode,
** * Creating a table (may require moving an overflow page).
*/
static int accessPayload(
BtCursor pCur, /* Cursor pointing to entry to read from */
u32 offset, /* Begin reading this far into payload */
u32 amt, /* Read this many bytes */
byte[] pBuf, /* Write the bytes into this buffer */
int eOp /* zero to read. non-zero to write. */
)
{
u32 pBufOffset = 0;
byte[] aPayload;
int rc = SQLITE_OK;
u32 nKey;
int iIdx = 0;
MemPage pPage = pCur.apPage[pCur.iPage]; /* Btree page of current entry */
BtShared pBt = pCur.pBt; /* Btree this cursor belongs to */
Debug.Assert( pPage != null );
Debug.Assert( pCur.eState == CURSOR_VALID );
Debug.Assert( pCur.aiIdx[pCur.iPage] < pPage.nCell );
Debug.Assert( cursorHoldsMutex( pCur ) );
getCellInfo( pCur );
aPayload = pCur.info.pCell; //pCur.info.pCell + pCur.info.nHeader;
nKey = (u32)( pPage.intKey != 0 ? 0 : (int)pCur.info.nKey );
if ( NEVER( offset + amt > nKey + pCur.info.nData )
|| pCur.info.nLocal > pBt.usableSize//&aPayload[pCur.info.nLocal] > &pPage.aData[pBt.usableSize]
)
{
/* Trying to read or write past the end of the data is an error */
return SQLITE_CORRUPT_BKPT();
}
/* Check if data must be read/written to/from the btree page itself. */
if ( offset < pCur.info.nLocal )
{
int a = (int)amt;
if ( a + offset > pCur.info.nLocal )
{
a = (int)( pCur.info.nLocal - offset );
}
rc = copyPayload( aPayload, (u32)( offset + pCur.info.iCell + pCur.info.nHeader ), pBuf, pBufOffset, (u32)a, eOp, pPage.pDbPage );
offset = 0;
pBufOffset += (u32)a; //pBuf += a;
amt -= (u32)a;
}
else
{
offset -= pCur.info.nLocal;
}
if ( rc == SQLITE_OK && amt > 0 )
{
u32 ovflSize = (u32)( pBt.usableSize - 4 ); /* Bytes content per ovfl page */
Pgno nextPage;
nextPage = sqlite3Get4byte( aPayload, pCur.info.nLocal + pCur.info.iCell + pCur.info.nHeader );
#if !SQLITE_OMIT_INCRBLOB
/* If the isIncrblobHandle flag is set and the BtCursor.aOverflow[]
** has not been allocated, allocate it now. The array is sized at
** one entry for each overflow page in the overflow chain. The
** page number of the first overflow page is stored in aOverflow[0],
** etc. A value of 0 in the aOverflow[] array means "not yet known"
** (the cache is lazily populated).
*/
if( pCur.isIncrblobHandle && !pCur.aOverflow ){
int nOvfl = (pCur.info.nPayload-pCur.info.nLocal+ovflSize-1)/ovflSize;
pCur.aOverflow = (Pgno *)sqlite3MallocZero(sizeof(Pgno)*nOvfl);
/* nOvfl is always positive. If it were zero, fetchPayload would have
** been used instead of this routine. */
if( ALWAYS(nOvfl) && !pCur.aOverflow ){
rc = SQLITE_NOMEM;
}
}
/* If the overflow page-list cache has been allocated and the
** entry for the first required overflow page is valid, skip
** directly to it.
*/
if( pCur.aOverflow && pCur.aOverflow[offset/ovflSize] ){
iIdx = (offset/ovflSize);
nextPage = pCur.aOverflow[iIdx];
offset = (offset%ovflSize);
}
#endif
for ( ; rc == SQLITE_OK && amt > 0 && nextPage != 0; iIdx++ )
{
#if !SQLITE_OMIT_INCRBLOB
/* If required, populate the overflow page-list cache. */
if( pCur.aOverflow ){
Debug.Assert(!pCur.aOverflow[iIdx] || pCur.aOverflow[iIdx]==nextPage);
pCur.aOverflow[iIdx] = nextPage;
}
#endif
MemPage MemPageDummy = null;
if ( offset >= ovflSize )
{
/* The only reason to read this page is to obtain the page
** number for the next page in the overflow chain. The page
** data is not required. So first try to lookup the overflow
** page-list cache, if any, then fall back to the getOverflowPage()
** function.
*/
#if !SQLITE_OMIT_INCRBLOB
if( pCur.aOverflow && pCur.aOverflow[iIdx+1] ){
nextPage = pCur.aOverflow[iIdx+1];
} else
#endif
rc = getOverflowPage( pBt, nextPage, out MemPageDummy, out nextPage );
offset -= ovflSize;
}
else
{
/* Need to read this page properly. It contains some of the
** range of data that is being read (eOp==null) or written (eOp!=null).
*/
PgHdr pDbPage = new PgHdr();
int a = (int)amt;
rc = sqlite3PagerGet( pBt.pPager, nextPage, ref pDbPage );
if ( rc == SQLITE_OK )
{
aPayload = sqlite3PagerGetData( pDbPage );
nextPage = sqlite3Get4byte( aPayload );
if ( a + offset > ovflSize )
{
a = (int)( ovflSize - offset );
}
rc = copyPayload( aPayload, offset + 4, pBuf, pBufOffset, (u32)a, eOp, pDbPage );
sqlite3PagerUnref( pDbPage );
offset = 0;
amt -= (u32)a;
pBufOffset += (u32)a;//pBuf += a;
}
}
}
}
if ( rc == SQLITE_OK && amt > 0 )
{
return SQLITE_CORRUPT_BKPT();
}
return rc;
}
/*
** Read part of the key associated with cursor pCur. Exactly
** "amt" bytes will be transfered into pBuf[]. The transfer
** begins at "offset".
**
** The caller must ensure that pCur is pointing to a valid row
** in the table.
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong. An error is returned if "offset+amt" is larger than
** the available payload.
*/
static int sqlite3BtreeKey( BtCursor pCur, u32 offset, u32 amt, byte[] pBuf )
{
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_VALID );
Debug.Assert( pCur.iPage >= 0 && pCur.apPage[pCur.iPage] != null );
Debug.Assert( pCur.aiIdx[pCur.iPage] < pCur.apPage[pCur.iPage].nCell );
return accessPayload( pCur, offset, amt, pBuf, 0 );
}
/*
** Read part of the data associated with cursor pCur. Exactly
** "amt" bytes will be transfered into pBuf[]. The transfer
** begins at "offset".
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong. An error is returned if "offset+amt" is larger than
** the available payload.
*/
static int sqlite3BtreeData( BtCursor pCur, u32 offset, u32 amt, byte[] pBuf )
{
int rc;
#if !SQLITE_OMIT_INCRBLOB
if ( pCur.eState==CURSOR_INVALID ){
return SQLITE_ABORT;
}
#endif
Debug.Assert( cursorHoldsMutex( pCur ) );
rc = restoreCursorPosition( pCur );
if ( rc == SQLITE_OK )
{
Debug.Assert( pCur.eState == CURSOR_VALID );
Debug.Assert( pCur.iPage >= 0 && pCur.apPage[pCur.iPage] != null );
Debug.Assert( pCur.aiIdx[pCur.iPage] < pCur.apPage[pCur.iPage].nCell );
rc = accessPayload( pCur, offset, amt, pBuf, 0 );
}
return rc;
}
/*
** Return a pointer to payload information from the entry that the
** pCur cursor is pointing to. The pointer is to the beginning of
** the key if skipKey==null and it points to the beginning of data if
** skipKey==1. The number of bytes of available key/data is written
** into pAmt. If pAmt==null, then the value returned will not be
** a valid pointer.
**
** This routine is an optimization. It is common for the entire key
** and data to fit on the local page and for there to be no overflow
** pages. When that is so, this routine can be used to access the
** key and data without making a copy. If the key and/or data spills
** onto overflow pages, then accessPayload() must be used to reassemble
** the key/data and copy it into a preallocated buffer.
**
** The pointer returned by this routine looks directly into the cached
** page of the database. The data might change or move the next time
** any btree routine is called.
*/
static byte[] fetchPayload(
BtCursor pCur, /* Cursor pointing to entry to read from */
ref int pAmt, /* Write the number of available bytes here */
ref int outOffset, /* Offset into Buffer */
bool skipKey /* read beginning at data if this is true */
)
{
byte[] aPayload;
MemPage pPage;
u32 nKey;
u32 nLocal;
Debug.Assert( pCur != null && pCur.iPage >= 0 && pCur.apPage[pCur.iPage] != null );
Debug.Assert( pCur.eState == CURSOR_VALID );
Debug.Assert( cursorHoldsMutex( pCur ) );
outOffset = -1;
pPage = pCur.apPage[pCur.iPage];
Debug.Assert( pCur.aiIdx[pCur.iPage] < pPage.nCell );
if ( NEVER( pCur.info.nSize == 0 ) )
{
btreeParseCell( pCur.apPage[pCur.iPage], pCur.aiIdx[pCur.iPage],
ref pCur.info );
}
//aPayload = pCur.info.pCell;
//aPayload += pCur.info.nHeader;
aPayload = sqlite3Malloc( pCur.info.nSize - pCur.info.nHeader );
if ( pPage.intKey != 0 )
{
nKey = 0;
}
else
{
nKey = (u32)pCur.info.nKey;
}
if ( skipKey )
{
//aPayload += nKey;
outOffset = (int)( pCur.info.iCell + pCur.info.nHeader + nKey );
Buffer.BlockCopy( pCur.info.pCell, outOffset, aPayload, 0, (int)( pCur.info.nSize - pCur.info.nHeader - nKey ) );
nLocal = pCur.info.nLocal - nKey;
}
else
{
outOffset = (int)( pCur.info.iCell + pCur.info.nHeader );
Buffer.BlockCopy( pCur.info.pCell, outOffset, aPayload, 0, pCur.info.nSize - pCur.info.nHeader );
nLocal = pCur.info.nLocal;
Debug.Assert( nLocal <= nKey );
}
pAmt = (int)nLocal;
return aPayload;
}
/*
** For the entry that cursor pCur is point to, return as
** many bytes of the key or data as are available on the local
** b-tree page. Write the number of available bytes into pAmt.
**
** The pointer returned is ephemeral. The key/data may move
** or be destroyed on the next call to any Btree routine,
** including calls from other threads against the same cache.
** Hence, a mutex on the BtShared should be held prior to calling
** this routine.
**
** These routines is used to get quick access to key and data
** in the common case where no overflow pages are used.
*/
static byte[] sqlite3BtreeKeyFetch( BtCursor pCur, ref int pAmt, ref int outOffset )
{
byte[] p = null;
Debug.Assert( sqlite3_mutex_held( pCur.pBtree.db.mutex ) );
Debug.Assert( cursorHoldsMutex( pCur ) );
if ( ALWAYS( pCur.eState == CURSOR_VALID ) )
{
p = fetchPayload( pCur, ref pAmt, ref outOffset, false );
}
return p;
}
static byte[] sqlite3BtreeDataFetch( BtCursor pCur, ref int pAmt, ref int outOffset )
{
byte[] p = null;
Debug.Assert( sqlite3_mutex_held( pCur.pBtree.db.mutex ) );
Debug.Assert( cursorHoldsMutex( pCur ) );
if ( ALWAYS( pCur.eState == CURSOR_VALID ) )
{
p = fetchPayload( pCur, ref pAmt, ref outOffset, true );
}
return p;
}
/*
** Move the cursor down to a new child page. The newPgno argument is the
** page number of the child page to move to.
**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild( BtCursor pCur, u32 newPgno )
{
int rc;
int i = pCur.iPage;
MemPage pNewPage = new MemPage();
BtShared pBt = pCur.pBt;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_VALID );
Debug.Assert( pCur.iPage < BTCURSOR_MAX_DEPTH );
if ( pCur.iPage >= ( BTCURSOR_MAX_DEPTH - 1 ) )
{
return SQLITE_CORRUPT_BKPT();
}
rc = getAndInitPage( pBt, newPgno, ref pNewPage );
if ( rc != 0 )
return rc;
pCur.apPage[i + 1] = pNewPage;
pCur.aiIdx[i + 1] = 0;
pCur.iPage++;
pCur.info.nSize = 0;
pCur.validNKey = false;
if ( pNewPage.nCell < 1 || pNewPage.intKey != pCur.apPage[i].intKey )
{
return SQLITE_CORRUPT_BKPT();
}
return SQLITE_OK;
}
#if !NDEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of
** cells in pParent, that page number iChild is the right-child of
** the page.
*/
static void assertParentIndex( MemPage pParent, int iIdx, Pgno iChild )
{
Debug.Assert( iIdx <= pParent.nCell );
if ( iIdx == pParent.nCell )
{
Debug.Assert( sqlite3Get4byte( pParent.aData, pParent.hdrOffset + 8 ) == iChild );
}
else
{
Debug.Assert( sqlite3Get4byte( pParent.aData, findCell( pParent, iIdx ) ) == iChild );
}
}
#else
//# define assertParentIndex(x,y,z)
static void assertParentIndex(MemPage pParent, int iIdx, Pgno iChild) { }
#endif
/*
** Move the cursor up to the parent page.
**
** pCur.idx is set to the cell index that contains the pointer
** to the page we are coming from. If we are coming from the
** right-most child page then pCur.idx is set to one more than
** the largest cell index.
*/
static void moveToParent( BtCursor pCur )
{
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_VALID );
Debug.Assert( pCur.iPage > 0 );
Debug.Assert( pCur.apPage[pCur.iPage] != null );
assertParentIndex(
pCur.apPage[pCur.iPage - 1],
pCur.aiIdx[pCur.iPage - 1],
pCur.apPage[pCur.iPage].pgno
);
releasePage( pCur.apPage[pCur.iPage] );
pCur.iPage--;
pCur.info.nSize = 0;
pCur.validNKey = false;
}
/*
** Move the cursor to point to the root page of its b-tree structure.
**
** If the table has a virtual root page, then the cursor is moved to point
** to the virtual root page instead of the actual root page. A table has a
** virtual root page when the actual root page contains no cells and a
** single child page. This can only happen with the table rooted at page 1.
**
** If the b-tree structure is empty, the cursor state is set to
** CURSOR_INVALID. Otherwise, the cursor is set to point to the first
** cell located on the root (or virtual root) page and the cursor state
** is set to CURSOR_VALID.
**
** If this function returns successfully, it may be assumed that the
** page-header flags indicate that the [virtual] root-page is the expected
** kind of b-tree page (i.e. if when opening the cursor the caller did not
** specify a KeyInfo structure the flags byte is set to 0x05 or 0x0D,
** indicating a table b-tree, or if the caller did specify a KeyInfo
** structure the flags byte is set to 0x02 or 0x0A, indicating an index
** b-tree).
*/
static int moveToRoot( BtCursor pCur )
{
MemPage pRoot;
int rc = SQLITE_OK;
Btree p = pCur.pBtree;
BtShared pBt = p.pBt;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
Debug.Assert( CURSOR_VALID < CURSOR_REQUIRESEEK );
Debug.Assert( CURSOR_FAULT > CURSOR_REQUIRESEEK );
if ( pCur.eState >= CURSOR_REQUIRESEEK )
{
if ( pCur.eState == CURSOR_FAULT )
{
Debug.Assert( pCur.skipNext != SQLITE_OK );
return pCur.skipNext;
}
sqlite3BtreeClearCursor( pCur );
}
if ( pCur.iPage >= 0 )
{
int i;
for ( i = 1; i <= pCur.iPage; i++ )
{
releasePage( pCur.apPage[i] );
}
pCur.iPage = 0;
}
else
{
rc = getAndInitPage( pBt, pCur.pgnoRoot, ref pCur.apPage[0] );
if ( rc != SQLITE_OK )
{
pCur.eState = CURSOR_INVALID;
return rc;
}
pCur.iPage = 0;
/* If pCur.pKeyInfo is not NULL, then the caller that opened this cursor
** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
** NULL, the caller expects a table b-tree. If this is not the case,
** return an SQLITE_CORRUPT error. */
Debug.Assert( pCur.apPage[0].intKey == 1 || pCur.apPage[0].intKey == 0 );
if ( ( pCur.pKeyInfo == null ) != ( pCur.apPage[0].intKey != 0 ) )
{
return SQLITE_CORRUPT_BKPT();
}
}
/* Assert that the root page is of the correct type. This must be the
** case as the call to this function that loaded the root-page (either
** this call or a previous invocation) would have detected corruption
** if the assumption were not true, and it is not possible for the flags
** byte to have been modified while this cursor is holding a reference
** to the page. */
pRoot = pCur.apPage[0];
Debug.Assert( pRoot.pgno == pCur.pgnoRoot );
Debug.Assert( pRoot.isInit != 0 && ( pCur.pKeyInfo == null ) == ( pRoot.intKey != 0 ) );
pCur.aiIdx[0] = 0;
pCur.info.nSize = 0;
pCur.atLast = 0;
pCur.validNKey = false;
if ( pRoot.nCell == 0 && 0 == pRoot.leaf )
{
Pgno subpage;
if ( pRoot.pgno != 1 )
return SQLITE_CORRUPT_BKPT();
subpage = sqlite3Get4byte( pRoot.aData, pRoot.hdrOffset + 8 );
pCur.eState = CURSOR_VALID;
rc = moveToChild( pCur, subpage );
}
else
{
pCur.eState = ( ( pRoot.nCell > 0 ) ? CURSOR_VALID : CURSOR_INVALID );
}
return rc;
}
/*
** Move the cursor down to the left-most leaf entry beneath the
** entry to which it is currently pointing.
**
** The left-most leaf is the one with the smallest key - the first
** in ascending order.
*/
static int moveToLeftmost( BtCursor pCur )
{
Pgno pgno;
int rc = SQLITE_OK;
MemPage pPage;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_VALID );
while ( rc == SQLITE_OK && 0 == ( pPage = pCur.apPage[pCur.iPage] ).leaf )
{
Debug.Assert( pCur.aiIdx[pCur.iPage] < pPage.nCell );
pgno = sqlite3Get4byte( pPage.aData, findCell( pPage, pCur.aiIdx[pCur.iPage] ) );
rc = moveToChild( pCur, pgno );
}
return rc;
}
/*
** Move the cursor down to the right-most leaf entry beneath the
** page to which it is currently pointing. Notice the difference
** between moveToLeftmost() and moveToRightmost(). moveToLeftmost()
** finds the left-most entry beneath the *entry* whereas moveToRightmost()
** finds the right-most entry beneath the page*.
**
** The right-most entry is the one with the largest key - the last
** key in ascending order.
*/
static int moveToRightmost( BtCursor pCur )
{
Pgno pgno;
int rc = SQLITE_OK;
MemPage pPage = null;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.eState == CURSOR_VALID );
while ( rc == SQLITE_OK && 0 == ( pPage = pCur.apPage[pCur.iPage] ).leaf )
{
pgno = sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 );
pCur.aiIdx[pCur.iPage] = pPage.nCell;
rc = moveToChild( pCur, pgno );
}
if ( rc == SQLITE_OK )
{
pCur.aiIdx[pCur.iPage] = (u16)( pPage.nCell - 1 );
pCur.info.nSize = 0;
pCur.validNKey = false;
}
return rc;
}
/* Move the cursor to the first entry in the table. Return SQLITE_OK
** on success. Set pRes to 0 if the cursor actually points to something
** or set pRes to 1 if the table is empty.
*/
static int sqlite3BtreeFirst( BtCursor pCur, ref int pRes )
{
int rc;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( sqlite3_mutex_held( pCur.pBtree.db.mutex ) );
rc = moveToRoot( pCur );
if ( rc == SQLITE_OK )
{
if ( pCur.eState == CURSOR_INVALID )
{
Debug.Assert( pCur.apPage[pCur.iPage].nCell == 0 );
pRes = 1;
}
else
{
Debug.Assert( pCur.apPage[pCur.iPage].nCell > 0 );
pRes = 0;
rc = moveToLeftmost( pCur );
}
}
return rc;
}
/* Move the cursor to the last entry in the table. Return SQLITE_OK
** on success. Set pRes to 0 if the cursor actually points to something
** or set pRes to 1 if the table is empty.
*/
static int sqlite3BtreeLast( BtCursor pCur, ref int pRes )
{
int rc;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( sqlite3_mutex_held( pCur.pBtree.db.mutex ) );
/* If the cursor already points to the last entry, this is a no-op. */
if ( CURSOR_VALID == pCur.eState && pCur.atLast != 0 )
{
#if SQLITE_DEBUG
/* This block serves to Debug.Assert() that the cursor really does point
** to the last entry in the b-tree. */
int ii;
for ( ii = 0; ii < pCur.iPage; ii++ )
{
Debug.Assert( pCur.aiIdx[ii] == pCur.apPage[ii].nCell );
}
Debug.Assert( pCur.aiIdx[pCur.iPage] == pCur.apPage[pCur.iPage].nCell - 1 );
Debug.Assert( pCur.apPage[pCur.iPage].leaf != 0 );
#endif
return SQLITE_OK;
}
rc = moveToRoot( pCur );
if ( rc == SQLITE_OK )
{
if ( CURSOR_INVALID == pCur.eState )
{
Debug.Assert( pCur.apPage[pCur.iPage].nCell == 0 );
pRes = 1;
}
else
{
Debug.Assert( pCur.eState == CURSOR_VALID );
pRes = 0;
rc = moveToRightmost( pCur );
pCur.atLast = (u8)( rc == SQLITE_OK ? 1 : 0 );
}
}
return rc;
}
/* Move the cursor so that it points to an entry near the key
** specified by pIdxKey or intKey. Return a success code.
**
** For INTKEY tables, the intKey parameter is used. pIdxKey
** must be NULL. For index tables, pIdxKey is used and intKey
** is ignored.
**
** If an exact match is not found, then the cursor is always
** left pointing at a leaf page which would hold the entry if it
** were present. The cursor might point to an entry that comes
** before or after the key.
**
** An integer is written into pRes which is the result of
** comparing the key with the entry to which the cursor is
** pointing. The meaning of the integer written into
** pRes is as follows:
**
** pRes<0 The cursor is left pointing at an entry that
** is smaller than intKey/pIdxKey or if the table is empty
** and the cursor is therefore left point to nothing.
**
** pRes==null The cursor is left pointing at an entry that
** exactly matches intKey/pIdxKey.
**
** pRes>0 The cursor is left pointing at an entry that
** is larger than intKey/pIdxKey.
**
*/
static int sqlite3BtreeMovetoUnpacked(
BtCursor pCur, /* The cursor to be moved */
UnpackedRecord pIdxKey, /* Unpacked index key */
i64 intKey, /* The table key */
int biasRight, /* If true, bias the search to the high end */
ref int pRes /* Write search results here */
)
{
int rc;
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( sqlite3_mutex_held( pCur.pBtree.db.mutex ) );
// Not needed in C# // Debug.Assert( pRes != 0 );
Debug.Assert( ( pIdxKey == null ) == ( pCur.pKeyInfo == null ) );
/* If the cursor is already positioned at the point we are trying
** to move to, then just return without doing any work */
if ( pCur.eState == CURSOR_VALID && pCur.validNKey
&& pCur.apPage[0].intKey != 0
)
{
if ( pCur.info.nKey == intKey )
{
pRes = 0;
return SQLITE_OK;
}
if ( pCur.atLast != 0 && pCur.info.nKey < intKey )
{
pRes = -1;
return SQLITE_OK;
}
}
rc = moveToRoot( pCur );
if ( rc != 0 )
{
return rc;
}
Debug.Assert( pCur.apPage[pCur.iPage] != null );
Debug.Assert( pCur.apPage[pCur.iPage].isInit != 0 );
Debug.Assert( pCur.apPage[pCur.iPage].nCell > 0 || pCur.eState == CURSOR_INVALID );
if ( pCur.eState == CURSOR_INVALID )
{
pRes = -1;
Debug.Assert( pCur.apPage[pCur.iPage].nCell == 0 );
return SQLITE_OK;
}
Debug.Assert( pCur.apPage[0].intKey != 0 || pIdxKey != null );
for ( ; ; )
{
int lwr, upr, idx;
Pgno chldPg;
MemPage pPage = pCur.apPage[pCur.iPage];
int c;
/* pPage.nCell must be greater than zero. If this is the root-page
** the cursor would have been INVALID above and this for(;;) loop
** not run. If this is not the root-page, then the moveToChild() routine
** would have already detected db corruption. Similarly, pPage must
** be the right kind (index or table) of b-tree page. Otherwise
** a moveToChild() or moveToRoot() call would have detected corruption. */
Debug.Assert( pPage.nCell > 0 );
Debug.Assert( pPage.intKey == ( ( pIdxKey == null ) ? 1 : 0 ) );
lwr = 0;
upr = pPage.nCell - 1;
if ( biasRight != 0 )
{
pCur.aiIdx[pCur.iPage] = (u16)( idx = upr );
}
else
{
pCur.aiIdx[pCur.iPage] = (u16)( idx = ( upr + lwr ) / 2 );
}
for ( ; ; )
{
int pCell; /* Pointer to current cell in pPage */
Debug.Assert( idx == pCur.aiIdx[pCur.iPage] );
pCur.info.nSize = 0;
pCell = findCell( pPage, idx ) + pPage.childPtrSize;
if ( pPage.intKey != 0 )
{
i64 nCellKey = 0;
if ( pPage.hasData != 0 )
{
u32 Dummy0 = 0;
pCell += getVarint32( pPage.aData, pCell, out Dummy0 );
}
getVarint( pPage.aData, pCell, out nCellKey );
if ( nCellKey == intKey )
{
c = 0;
}
else if ( nCellKey < intKey )
{
c = -1;
}
else
{
Debug.Assert( nCellKey > intKey );
c = +1;
}
pCur.validNKey = true;
pCur.info.nKey = nCellKey;
}
else
{
/* The maximum supported page-size is 65536 bytes. This means that
** the maximum number of record bytes stored on an index B-Tree
** page is less than 16384 bytes and may be stored as a 2-byte
** varint. This information is used to attempt to avoid parsing
** the entire cell by checking for the cases where the record is
** stored entirely within the b-tree page by inspecting the first
** 2 bytes of the cell.
*/
int nCell = pPage.aData[pCell + 0]; //pCell[0];
if ( 0 == ( nCell & 0x80 ) && nCell <= pPage.maxLocal )
{
/* This branch runs if the record-size field of the cell is a
** single byte varint and the record fits entirely on the main
** b-tree page. */
c = sqlite3VdbeRecordCompare( nCell, pPage.aData, pCell + 1, pIdxKey ); //c = sqlite3VdbeRecordCompare( nCell, (void*)&pCell[1], pIdxKey );
}
else if ( 0 == ( pPage.aData[pCell + 1] & 0x80 )//!(pCell[1] & 0x80)
&& ( nCell = ( ( nCell & 0x7f ) << 7 ) + pPage.aData[pCell + 1] ) <= pPage.maxLocal//pCell[1])<=pPage.maxLocal
)
{
/* The record-size field is a 2 byte varint and the record
** fits entirely on the main b-tree page. */
c = sqlite3VdbeRecordCompare( nCell, pPage.aData, pCell + 2, pIdxKey ); //c = sqlite3VdbeRecordCompare( nCell, (void*)&pCell[2], pIdxKey );
}
else
{
/* The record flows over onto one or more overflow pages. In
** this case the whole cell needs to be parsed, a buffer allocated
** and accessPayload() used to retrieve the record into the
** buffer before VdbeRecordCompare() can be called. */
u8[] pCellKey;
u8[] pCellBody = new u8[pPage.aData.Length - pCell + pPage.childPtrSize];
Buffer.BlockCopy( pPage.aData, pCell - pPage.childPtrSize, pCellBody, 0, pCellBody.Length );// u8 * const pCellBody = pCell - pPage->childPtrSize;
btreeParseCellPtr( pPage, pCellBody, ref pCur.info );
nCell = (int)pCur.info.nKey;
pCellKey = sqlite3Malloc( nCell );
//if ( pCellKey == null )
//{
// rc = SQLITE_NOMEM;
// goto moveto_finish;
//}
rc = accessPayload( pCur, 0, (u32)nCell, pCellKey, 0 );
if ( rc != 0 )
{
pCellKey = null;// sqlite3_free(ref pCellKey );
goto moveto_finish;
}
c = sqlite3VdbeRecordCompare( nCell, pCellKey, pIdxKey );
pCellKey = null;// sqlite3_free(ref pCellKey );
}
}
if ( c == 0 )
{
if ( pPage.intKey != 0 && 0 == pPage.leaf )
{
lwr = idx;
upr = lwr - 1;
break;
}
else
{
pRes = 0;
rc = SQLITE_OK;
goto moveto_finish;
}
}
if ( c < 0 )
{
lwr = idx + 1;
}
else
{
upr = idx - 1;
}
if ( lwr > upr )
{
break;
}
pCur.aiIdx[pCur.iPage] = (u16)( idx = ( lwr + upr ) / 2 );
}
Debug.Assert( lwr == upr + 1 );
Debug.Assert( pPage.isInit != 0 );
if ( pPage.leaf != 0 )
{
chldPg = 0;
}
else if ( lwr >= pPage.nCell )
{
chldPg = sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 );
}
else
{
chldPg = sqlite3Get4byte( pPage.aData, findCell( pPage, lwr ) );
}
if ( chldPg == 0 )
{
Debug.Assert( pCur.aiIdx[pCur.iPage] < pCur.apPage[pCur.iPage].nCell );
pRes = c;
rc = SQLITE_OK;
goto moveto_finish;
}
pCur.aiIdx[pCur.iPage] = (u16)lwr;
pCur.info.nSize = 0;
pCur.validNKey = false;
rc = moveToChild( pCur, chldPg );
if ( rc != 0 )
goto moveto_finish;
}
moveto_finish:
return rc;
}
/*
** Return TRUE if the cursor is not pointing at an entry of the table.
**
** TRUE will be returned after a call to sqlite3BtreeNext() moves
** past the last entry in the table or sqlite3BtreePrev() moves past
** the first entry. TRUE is also returned if the table is empty.
*/
static bool sqlite3BtreeEof( BtCursor pCur )
{
/* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
** have been deleted? This API will need to change to return an error code
** as well as the boolean result value.
*/
return ( CURSOR_VALID != pCur.eState );
}
/*
** Advance the cursor to the next entry in the database. If
** successful then set pRes=0. If the cursor
** was already pointing to the last entry in the database before
** this routine was called, then set pRes=1.
*/
static int sqlite3BtreeNext( BtCursor pCur, ref int pRes )
{
int rc;
int idx;
MemPage pPage;
Debug.Assert( cursorHoldsMutex( pCur ) );
rc = restoreCursorPosition( pCur );
if ( rc != SQLITE_OK )
{
return rc;
}
// Not needed in C# // Debug.Assert( pRes != 0 );
if ( CURSOR_INVALID == pCur.eState )
{
pRes = 1;
return SQLITE_OK;
}
if ( pCur.skipNext > 0 )
{
pCur.skipNext = 0;
pRes = 0;
return SQLITE_OK;
}
pCur.skipNext = 0;
pPage = pCur.apPage[pCur.iPage];
idx = ++pCur.aiIdx[pCur.iPage];
Debug.Assert( pPage.isInit != 0 );
Debug.Assert( idx <= pPage.nCell );
pCur.info.nSize = 0;
pCur.validNKey = false;
if ( idx >= pPage.nCell )
{
if ( 0 == pPage.leaf )
{
rc = moveToChild( pCur, sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 ) );
if ( rc != 0 )
return rc;
rc = moveToLeftmost( pCur );
pRes = 0;
return rc;
}
do
{
if ( pCur.iPage == 0 )
{
pRes = 1;
pCur.eState = CURSOR_INVALID;
return SQLITE_OK;
}
moveToParent( pCur );
pPage = pCur.apPage[pCur.iPage];
} while ( pCur.aiIdx[pCur.iPage] >= pPage.nCell );
pRes = 0;
if ( pPage.intKey != 0 )
{
rc = sqlite3BtreeNext( pCur, ref pRes );
}
else
{
rc = SQLITE_OK;
}
return rc;
}
pRes = 0;
if ( pPage.leaf != 0 )
{
return SQLITE_OK;
}
rc = moveToLeftmost( pCur );
return rc;
}
/*
** Step the cursor to the back to the previous entry in the database. If
** successful then set pRes=0. If the cursor
** was already pointing to the first entry in the database before
** this routine was called, then set pRes=1.
*/
static int sqlite3BtreePrevious( BtCursor pCur, ref int pRes )
{
int rc;
MemPage pPage;
Debug.Assert( cursorHoldsMutex( pCur ) );
rc = restoreCursorPosition( pCur );
if ( rc != SQLITE_OK )
{
return rc;
}
pCur.atLast = 0;
if ( CURSOR_INVALID == pCur.eState )
{
pRes = 1;
return SQLITE_OK;
}
if ( pCur.skipNext < 0 )
{
pCur.skipNext = 0;
pRes = 0;
return SQLITE_OK;
}
pCur.skipNext = 0;
pPage = pCur.apPage[pCur.iPage];
Debug.Assert( pPage.isInit != 0 );
if ( 0 == pPage.leaf )
{
int idx = pCur.aiIdx[pCur.iPage];
rc = moveToChild( pCur, sqlite3Get4byte( pPage.aData, findCell( pPage, idx ) ) );
if ( rc != 0 )
{
return rc;
}
rc = moveToRightmost( pCur );
}
else
{
while ( pCur.aiIdx[pCur.iPage] == 0 )
{
if ( pCur.iPage == 0 )
{
pCur.eState = CURSOR_INVALID;
pRes = 1;
return SQLITE_OK;
}
moveToParent( pCur );
}
pCur.info.nSize = 0;
pCur.validNKey = false;
pCur.aiIdx[pCur.iPage]--;
pPage = pCur.apPage[pCur.iPage];
if ( pPage.intKey != 0 && 0 == pPage.leaf )
{
rc = sqlite3BtreePrevious( pCur, ref pRes );
}
else
{
rc = SQLITE_OK;
}
}
pRes = 0;
return rc;
}
/*
** Allocate a new page from the database file.
**
** The new page is marked as dirty. (In other words, sqlite3PagerWrite()
** has already been called on the new page.) The new page has also
** been referenced and the calling routine is responsible for calling
** sqlite3PagerUnref() on the new page when it is done.
**
** SQLITE_OK is returned on success. Any other return value indicates
** an error. ppPage and pPgno are undefined in the event of an error.
** Do not invoke sqlite3PagerUnref() on ppPage if an error is returned.
**
** If the "nearby" parameter is not 0, then a (feeble) effort is made to
** locate a page close to the page number "nearby". This can be used in an
** attempt to keep related pages close to each other in the database file,
** which in turn can make database access faster.
**
** If the "exact" parameter is not 0, and the page-number nearby exists
** anywhere on the free-list, then it is guarenteed to be returned. This
** is only used by auto-vacuum databases when allocating a new table.
*/
static int allocateBtreePage(
BtShared pBt,
ref MemPage ppPage,
ref Pgno pPgno,
Pgno nearby,
u8 exact
)
{
MemPage pPage1;
int rc;
u32 n; /* Number of pages on the freelist */
u32 k; /* Number of leaves on the trunk of the freelist */
MemPage pTrunk = null;
MemPage pPrevTrunk = null;
Pgno mxPage; /* Total size of the database file */
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
pPage1 = pBt.pPage1;
mxPage = btreePagecount( pBt );
n = sqlite3Get4byte( pPage1.aData, 36 );
testcase( n == mxPage - 1 );
if ( n >= mxPage )
{
return SQLITE_CORRUPT_BKPT();
}
if ( n > 0 )
{
/* There are pages on the freelist. Reuse one of those pages. */
Pgno iTrunk;
u8 searchList = 0; /* If the free-list must be searched for 'nearby' */
/* If the 'exact' parameter was true and a query of the pointer-map
** shows that the page 'nearby' is somewhere on the free-list, then
** the entire-list will be searched for that page.
*/
#if !SQLITE_OMIT_AUTOVACUUM
if ( exact != 0 && nearby <= mxPage )
{
u8 eType = 0;
Debug.Assert( nearby > 0 );
Debug.Assert( pBt.autoVacuum );
u32 Dummy0 = 0;
rc = ptrmapGet( pBt, nearby, ref eType, ref Dummy0 );
if ( rc != 0 )
return rc;
if ( eType == PTRMAP_FREEPAGE )
{
searchList = 1;
}
pPgno = nearby;
}
#endif
/* Decrement the free-list count by 1. Set iTrunk to the index of the
** first free-list trunk page. iPrevTrunk is initially 1.
*/
rc = sqlite3PagerWrite( pPage1.pDbPage );
if ( rc != 0 )
return rc;
sqlite3Put4byte( pPage1.aData, (u32)36, n - 1 );
/* The code within this loop is run only once if the 'searchList' variable
** is not true. Otherwise, it runs once for each trunk-page on the
** free-list until the page 'nearby' is located.
*/
do
{
pPrevTrunk = pTrunk;
if ( pPrevTrunk != null )
{
iTrunk = sqlite3Get4byte( pPrevTrunk.aData, 0 );
}
else
{
iTrunk = sqlite3Get4byte( pPage1.aData, 32 );
}
testcase( iTrunk == mxPage );
if ( iTrunk > mxPage )
{
rc = SQLITE_CORRUPT_BKPT();
}
else
{
rc = btreeGetPage( pBt, iTrunk, ref pTrunk, 0 );
}
if ( rc != 0 )
{
pTrunk = null;
goto end_allocate_page;
}
k = sqlite3Get4byte( pTrunk.aData, 4 ); /* # of leaves on this trunk page */
if ( k == 0 && 0 == searchList )
{
/* The trunk has no leaves and the list is not being searched.
** So extract the trunk page itself and use it as the newly
** allocated page */
Debug.Assert( pPrevTrunk == null );
rc = sqlite3PagerWrite( pTrunk.pDbPage );
if ( rc != 0 )
{
goto end_allocate_page;
}
pPgno = iTrunk;
Buffer.BlockCopy( pTrunk.aData, 0, pPage1.aData, 32, 4 );//memcpy( pPage1.aData[32], ref pTrunk.aData[0], 4 );
ppPage = pTrunk;
pTrunk = null;
TRACE( "ALLOCATE: %d trunk - %d free pages left\n", pPgno, n - 1 );
}
else if ( k > (u32)( pBt.usableSize / 4 - 2 ) )
{
/* Value of k is out of range. Database corruption */
rc = SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
#if !SQLITE_OMIT_AUTOVACUUM
}
else if ( searchList != 0 && nearby == iTrunk )
{
/* The list is being searched and this trunk page is the page
** to allocate, regardless of whether it has leaves.
*/
Debug.Assert( pPgno == iTrunk );
ppPage = pTrunk;
searchList = 0;
rc = sqlite3PagerWrite( pTrunk.pDbPage );
if ( rc != 0 )
{
goto end_allocate_page;
}
if ( k == 0 )
{
if ( null == pPrevTrunk )
{
//memcpy(pPage1.aData[32], pTrunk.aData[0], 4);
pPage1.aData[32 + 0] = pTrunk.aData[0 + 0];
pPage1.aData[32 + 1] = pTrunk.aData[0 + 1];
pPage1.aData[32 + 2] = pTrunk.aData[0 + 2];
pPage1.aData[32 + 3] = pTrunk.aData[0 + 3];
}
else
{
rc = sqlite3PagerWrite( pPrevTrunk.pDbPage );
if ( rc != SQLITE_OK )
{
goto end_allocate_page;
}
//memcpy(pPrevTrunk.aData[0], pTrunk.aData[0], 4);
pPrevTrunk.aData[0 + 0] = pTrunk.aData[0 + 0];
pPrevTrunk.aData[0 + 1] = pTrunk.aData[0 + 1];
pPrevTrunk.aData[0 + 2] = pTrunk.aData[0 + 2];
pPrevTrunk.aData[0 + 3] = pTrunk.aData[0 + 3];
}
}
else
{
/* The trunk page is required by the caller but it contains
** pointers to free-list leaves. The first leaf becomes a trunk
** page in this case.
*/
MemPage pNewTrunk = new MemPage();
Pgno iNewTrunk = sqlite3Get4byte( pTrunk.aData, 8 );
if ( iNewTrunk > mxPage )
{
rc = SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
}
testcase( iNewTrunk == mxPage );
rc = btreeGetPage( pBt, iNewTrunk, ref pNewTrunk, 0 );
if ( rc != SQLITE_OK )
{
goto end_allocate_page;
}
rc = sqlite3PagerWrite( pNewTrunk.pDbPage );
if ( rc != SQLITE_OK )
{
releasePage( pNewTrunk );
goto end_allocate_page;
}
//memcpy(pNewTrunk.aData[0], pTrunk.aData[0], 4);
pNewTrunk.aData[0 + 0] = pTrunk.aData[0 + 0];
pNewTrunk.aData[0 + 1] = pTrunk.aData[0 + 1];
pNewTrunk.aData[0 + 2] = pTrunk.aData[0 + 2];
pNewTrunk.aData[0 + 3] = pTrunk.aData[0 + 3];
sqlite3Put4byte( pNewTrunk.aData, (u32)4, (u32)( k - 1 ) );
Buffer.BlockCopy( pTrunk.aData, 12, pNewTrunk.aData, 8, (int)( k - 1 ) * 4 );//memcpy( pNewTrunk.aData[8], ref pTrunk.aData[12], ( k - 1 ) * 4 );
releasePage( pNewTrunk );
if ( null == pPrevTrunk )
{
Debug.Assert( sqlite3PagerIswriteable( pPage1.pDbPage ) );
sqlite3Put4byte( pPage1.aData, (u32)32, iNewTrunk );
}
else
{
rc = sqlite3PagerWrite( pPrevTrunk.pDbPage );
if ( rc != 0 )
{
goto end_allocate_page;
}
sqlite3Put4byte( pPrevTrunk.aData, (u32)0, iNewTrunk );
}
}
pTrunk = null;
TRACE( "ALLOCATE: %d trunk - %d free pages left\n", pPgno, n - 1 );
#endif
}
else if ( k > 0 )
{
/* Extract a leaf from the trunk */
u32 closest;
Pgno iPage;
byte[] aData = pTrunk.aData;
if ( nearby > 0 )
{
u32 i;
int dist;
closest = 0;
dist = sqlite3AbsInt32( (int)(sqlite3Get4byte( aData, 8 ) - nearby ));
for ( i = 1; i < k; i++ )
{
int d2 = sqlite3AbsInt32( (int)(sqlite3Get4byte( aData, 8 + i * 4 ) - nearby ));
if ( d2 < dist )
{
closest = i;
dist = d2;
}
}
}
else
{
closest = 0;
}
iPage = sqlite3Get4byte( aData, 8 + closest * 4 );
testcase( iPage == mxPage );
if ( iPage > mxPage )
{
rc = SQLITE_CORRUPT_BKPT();
goto end_allocate_page;
}
testcase( iPage == mxPage );
if ( 0 == searchList || iPage == nearby )
{
int noContent;
pPgno = iPage;
TRACE( "ALLOCATE: %d was leaf %d of %d on trunk %d" +
": %d more free pages\n",
pPgno, closest + 1, k, pTrunk.pgno, n - 1 );
rc = sqlite3PagerWrite( pTrunk.pDbPage );
if ( rc != 0)
goto end_allocate_page;
if ( closest < k - 1 )
{
Buffer.BlockCopy( aData, (int)( 4 + k * 4 ), aData, 8 + (int)closest * 4, 4 );//memcpy( aData[8 + closest * 4], ref aData[4 + k * 4], 4 );
}
sqlite3Put4byte( aData, (u32)4, ( k - 1 ) );// sqlite3Put4byte( aData, 4, k - 1 );
noContent = !btreeGetHasContent( pBt, pPgno ) ? 1 : 0;
rc = btreeGetPage( pBt, pPgno, ref ppPage, noContent );
if ( rc == SQLITE_OK )
{
rc = sqlite3PagerWrite( ( ppPage ).pDbPage );
if ( rc != SQLITE_OK )
{
releasePage( ppPage );
}
}
searchList = 0;
}
}
releasePage( pPrevTrunk );
pPrevTrunk = null;
} while ( searchList != 0 );
}
else
{
/* There are no pages on the freelist, so create a new page at the
** end of the file */
rc = sqlite3PagerWrite( pBt.pPage1.pDbPage );
if ( rc != 0 )
return rc;
pBt.nPage++;
if ( pBt.nPage == PENDING_BYTE_PAGE( pBt ) )
pBt.nPage++;
#if !SQLITE_OMIT_AUTOVACUUM
if ( pBt.autoVacuum && PTRMAP_ISPAGE( pBt, pBt.nPage ) )
{
/* If pPgno refers to a pointer-map page, allocate two new pages
** at the end of the file instead of one. The first allocated page
** becomes a new pointer-map page, the second is used by the caller.
*/
MemPage pPg = null;
TRACE( "ALLOCATE: %d from end of file (pointer-map page)\n", pPgno );
Debug.Assert( pBt.nPage != PENDING_BYTE_PAGE( pBt ) );
rc = btreeGetPage( pBt, pBt.nPage, ref pPg, 1 );
if ( rc == SQLITE_OK )
{
rc = sqlite3PagerWrite( pPg.pDbPage );
releasePage( pPg );
}
if ( rc != 0 )
return rc;
pBt.nPage++;
if ( pBt.nPage == PENDING_BYTE_PAGE( pBt ) )
{
pBt.nPage++;
}
}
#endif
sqlite3Put4byte( pBt.pPage1.aData, (u32)28, pBt.nPage );
pPgno = pBt.nPage;
Debug.Assert( pPgno != PENDING_BYTE_PAGE( pBt ) );
rc = btreeGetPage( pBt, pPgno, ref ppPage, 1 );
if ( rc != 0 )
return rc;
rc = sqlite3PagerWrite( ( ppPage ).pDbPage );
if ( rc != SQLITE_OK )
{
releasePage( ppPage );
}
TRACE( "ALLOCATE: %d from end of file\n", pPgno );
}
Debug.Assert( pPgno != PENDING_BYTE_PAGE( pBt ) );
end_allocate_page:
releasePage( pTrunk );
releasePage( pPrevTrunk );
if ( rc == SQLITE_OK )
{
if ( sqlite3PagerPageRefcount( ( ppPage ).pDbPage ) > 1 )
{
releasePage( ppPage );
return SQLITE_CORRUPT_BKPT();
}
( ppPage ).isInit = 0;
}
else
{
ppPage = null;
}
Debug.Assert( rc != SQLITE_OK || sqlite3PagerIswriteable( ( ppPage ).pDbPage ) );
return rc;
}
/*
** This function is used to add page iPage to the database file free-list.
** It is assumed that the page is not already a part of the free-list.
**
** The value passed as the second argument to this function is optional.
** If the caller happens to have a pointer to the MemPage object
** corresponding to page iPage handy, it may pass it as the second value.
** Otherwise, it may pass NULL.
**
** If a pointer to a MemPage object is passed as the second argument,
** its reference count is not altered by this function.
*/
static int freePage2( BtShared pBt, MemPage pMemPage, Pgno iPage )
{
MemPage pTrunk = null; /* Free-list trunk page */
Pgno iTrunk = 0; /* Page number of free-list trunk page */
MemPage pPage1 = pBt.pPage1; /* Local reference to page 1 */
MemPage pPage; /* Page being freed. May be NULL. */
int rc; /* Return Code */
int nFree; /* Initial number of pages on free-list */
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( iPage > 1 );
Debug.Assert( null == pMemPage || pMemPage.pgno == iPage );
if ( pMemPage != null )
{
pPage = pMemPage;
sqlite3PagerRef( pPage.pDbPage );
}
else
{
pPage = btreePageLookup( pBt, iPage );
}
/* Increment the free page count on pPage1 */
rc = sqlite3PagerWrite( pPage1.pDbPage );
if ( rc != 0 )
goto freepage_out;
nFree = (int)sqlite3Get4byte( pPage1.aData, 36 );
sqlite3Put4byte( pPage1.aData, 36, nFree + 1 );
if ( pBt.secureDelete )
{
/* If the secure_delete option is enabled, then
** always fully overwrite deleted information with zeros.
*/
if ( ( null == pPage && ( ( rc = btreeGetPage( pBt, iPage, ref pPage, 0 ) ) != 0 ) )
|| ( ( rc = sqlite3PagerWrite( pPage.pDbPage ) ) != 0 )
)
{
goto freepage_out;
}
Array.Clear( pPage.aData, 0, (int)pPage.pBt.pageSize );//memset(pPage->aData, 0, pPage->pBt->pageSize);
}
/* If the database supports auto-vacuum, write an entry in the pointer-map
** to indicate that the page is free.
*/
#if !SQLITE_OMIT_AUTOVACUUM // if ( ISAUTOVACUUM )
if ( pBt.autoVacuum )
#else
if (false)
#endif
{
ptrmapPut( pBt, iPage, PTRMAP_FREEPAGE, 0, ref rc );
if ( rc != 0 )
goto freepage_out;
}
/* Now manipulate the actual database free-list structure. There are two
** possibilities. If the free-list is currently empty, or if the first
** trunk page in the free-list is full, then this page will become a
** new free-list trunk page. Otherwise, it will become a leaf of the
** first trunk page in the current free-list. This block tests if it
** is possible to add the page as a new free-list leaf.
*/
if ( nFree != 0 )
{
u32 nLeaf; /* Initial number of leaf cells on trunk page */
iTrunk = sqlite3Get4byte( pPage1.aData, 32 );
rc = btreeGetPage( pBt, iTrunk, ref pTrunk, 0 );
if ( rc != SQLITE_OK )
{
goto freepage_out;
}
nLeaf = sqlite3Get4byte( pTrunk.aData, 4 );
Debug.Assert( pBt.usableSize > 32 );
if ( nLeaf > (u32)pBt.usableSize / 4 - 2 )
{
rc = SQLITE_CORRUPT_BKPT();
goto freepage_out;
}
if ( nLeaf < (u32)pBt.usableSize / 4 - 8 )
{
/* In this case there is room on the trunk page to insert the page
** being freed as a new leaf.
**
** Note that the trunk page is not really full until it contains
** usableSize/4 - 2 entries, not usableSize/4 - 8 entries as we have
** coded. But due to a coding error in versions of SQLite prior to
** 3.6.0, databases with freelist trunk pages holding more than
** usableSize/4 - 8 entries will be reported as corrupt. In order
** to maintain backwards compatibility with older versions of SQLite,
** we will continue to restrict the number of entries to usableSize/4 - 8
** for now. At some point in the future (once everyone has upgraded
** to 3.6.0 or later) we should consider fixing the conditional above
** to read "usableSize/4-2" instead of "usableSize/4-8".
*/
rc = sqlite3PagerWrite( pTrunk.pDbPage );
if ( rc == SQLITE_OK )
{
sqlite3Put4byte( pTrunk.aData, (u32)4, nLeaf + 1 );
sqlite3Put4byte( pTrunk.aData, (u32)8 + nLeaf * 4, iPage );
if ( pPage != null && !pBt.secureDelete )
{
sqlite3PagerDontWrite( pPage.pDbPage );
}
rc = btreeSetHasContent( pBt, iPage );
}
TRACE( "FREE-PAGE: %d leaf on trunk page %d\n", iPage, pTrunk.pgno );
goto freepage_out;
}
}
/* If control flows to this point, then it was not possible to add the
** the page being freed as a leaf page of the first trunk in the free-list.
** Possibly because the free-list is empty, or possibly because the
** first trunk in the free-list is full. Either way, the page being freed
** will become the new first trunk page in the free-list.
*/
if ( pPage == null && SQLITE_OK != ( rc = btreeGetPage( pBt, iPage, ref pPage, 0 ) ) )
{
goto freepage_out;
}
rc = sqlite3PagerWrite( pPage.pDbPage );
if ( rc != SQLITE_OK )
{
goto freepage_out;
}
sqlite3Put4byte( pPage.aData, iTrunk );
sqlite3Put4byte( pPage.aData, 4, 0 );
sqlite3Put4byte( pPage1.aData, (u32)32, iPage );
TRACE( "FREE-PAGE: %d new trunk page replacing %d\n", pPage.pgno, iTrunk );
freepage_out:
if ( pPage != null )
{
pPage.isInit = 0;
}
releasePage( pPage );
releasePage( pTrunk );
return rc;
}
static void freePage( MemPage pPage, ref int pRC )
{
if ( ( pRC ) == SQLITE_OK )
{
pRC = freePage2( pPage.pBt, pPage, pPage.pgno );
}
}
/*
** Free any overflow pages associated with the given Cell.
*/
static int clearCell( MemPage pPage, int pCell )
{
BtShared pBt = pPage.pBt;
CellInfo info = new CellInfo();
Pgno ovflPgno;
int rc;
int nOvfl;
u32 ovflPageSize;
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
btreeParseCellPtr( pPage, pCell, ref info );
if ( info.iOverflow == 0 )
{
return SQLITE_OK; /* No overflow pages. Return without doing anything */
}
ovflPgno = sqlite3Get4byte( pPage.aData, pCell, info.iOverflow );
Debug.Assert( pBt.usableSize > 4 );
ovflPageSize = (u16)( pBt.usableSize - 4 );
nOvfl = (int)( ( info.nPayload - info.nLocal + ovflPageSize - 1 ) / ovflPageSize );
Debug.Assert( ovflPgno == 0 || nOvfl > 0 );
while ( nOvfl-- != 0 )
{
Pgno iNext = 0;
MemPage pOvfl = null;
if ( ovflPgno < 2 || ovflPgno > btreePagecount( pBt ) )
{
/* 0 is not a legal page number and page 1 cannot be an
** overflow page. Therefore if ovflPgno<2 or past the end of the
** file the database must be corrupt. */
return SQLITE_CORRUPT_BKPT();
}
if ( nOvfl != 0 )
{
rc = getOverflowPage( pBt, ovflPgno, out pOvfl, out iNext );
if ( rc != 0 )
return rc;
}
if ( ( pOvfl != null || ( ( pOvfl = btreePageLookup( pBt, ovflPgno ) ) != null ) )
&& sqlite3PagerPageRefcount( pOvfl.pDbPage ) != 1
)
{
/* There is no reason any cursor should have an outstanding reference
** to an overflow page belonging to a cell that is being deleted/updated.
** So if there exists more than one reference to this page, then it
** must not really be an overflow page and the database must be corrupt.
** It is helpful to detect this before calling freePage2(), as
** freePage2() may zero the page contents if secure-delete mode is
** enabled. If this 'overflow' page happens to be a page that the
** caller is iterating through or using in some other way, this
** can be problematic.
*/
rc = SQLITE_CORRUPT_BKPT();
}
else
{
rc = freePage2( pBt, pOvfl, ovflPgno );
}
if ( pOvfl != null )
{
sqlite3PagerUnref( pOvfl.pDbPage );
}
if ( rc != 0 )
return rc;
ovflPgno = iNext;
}
return SQLITE_OK;
}
/*
** Create the byte sequence used to represent a cell on page pPage
** and write that byte sequence into pCell[]. Overflow pages are
** allocated and filled in as necessary. The calling procedure
** is responsible for making sure sufficient space has been allocated
** for pCell[].
**
** Note that pCell does not necessary need to point to the pPage.aData
** area. pCell might point to some temporary storage. The cell will
** be constructed in this temporary area then copied into pPage.aData
** later.
*/
static int fillInCell(
MemPage pPage, /* The page that contains the cell */
byte[] pCell, /* Complete text of the cell */
byte[] pKey, i64 nKey, /* The key */
byte[] pData, int nData, /* The data */
int nZero, /* Extra zero bytes to append to pData */
ref int pnSize /* Write cell size here */
)
{
int nPayload;
u8[] pSrc;
int pSrcIndex = 0;
int nSrc, n, rc;
int spaceLeft;
MemPage pOvfl = null;
MemPage pToRelease = null;
byte[] pPrior;
int pPriorIndex = 0;
byte[] pPayload;
int pPayloadIndex = 0;
BtShared pBt = pPage.pBt;
Pgno pgnoOvfl = 0;
int nHeader;
CellInfo info = new CellInfo();
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
/* pPage is not necessarily writeable since pCell might be auxiliary
** buffer space that is separate from the pPage buffer area */
// TODO -- Determine if the following Assert is needed under c#
//Debug.Assert( pCell < pPage.aData || pCell >= &pPage.aData[pBt.pageSize]
// || sqlite3PagerIswriteable(pPage.pDbPage) );
/* Fill in the header. */
nHeader = 0;
if ( 0 == pPage.leaf )
{
nHeader += 4;
}
if ( pPage.hasData != 0 )
{
nHeader += (int)putVarint( pCell, nHeader, (int)( nData + nZero ) ); //putVarint( pCell[nHeader], nData + nZero );
}
else
{
nData = nZero = 0;
}
nHeader += putVarint( pCell, nHeader, (u64)nKey ); //putVarint( pCell[nHeader], *(u64*)&nKey );
btreeParseCellPtr( pPage, pCell, ref info );
Debug.Assert( info.nHeader == nHeader );
Debug.Assert( info.nKey == nKey );
Debug.Assert( info.nData == (u32)( nData + nZero ) );
/* Fill in the payload */
nPayload = nData + nZero;
if ( pPage.intKey != 0 )
{
pSrc = pData;
nSrc = nData;
nData = 0;
}
else
{
if ( NEVER( nKey > 0x7fffffff || pKey == null ) )
{
return SQLITE_CORRUPT_BKPT();
}
nPayload += (int)nKey;
pSrc = pKey;
nSrc = (int)nKey;
}
pnSize = info.nSize;
spaceLeft = info.nLocal;
// pPayload = &pCell[nHeader];
pPayload = pCell;
pPayloadIndex = nHeader;
// pPrior = &pCell[info.iOverflow];
pPrior = pCell;
pPriorIndex = info.iOverflow;
while ( nPayload > 0 )
{
if ( spaceLeft == 0 )
{
#if !SQLITE_OMIT_AUTOVACUUM
Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
if ( pBt.autoVacuum )
{
do
{
pgnoOvfl++;
} while (
PTRMAP_ISPAGE( pBt, pgnoOvfl ) || pgnoOvfl == PENDING_BYTE_PAGE( pBt )
);
}
#endif
rc = allocateBtreePage( pBt, ref pOvfl, ref pgnoOvfl, pgnoOvfl, 0 );
#if !SQLITE_OMIT_AUTOVACUUM
/* If the database supports auto-vacuum, and the second or subsequent
** overflow page is being allocated, add an entry to the pointer-map
** for that page now.
**
** If this is the first overflow page, then write a partial entry
** to the pointer-map. If we write nothing to this pointer-map slot,
** then the optimistic overflow chain processing in clearCell()
** may misinterpret the uninitialised values and delete the
** wrong pages from the database.
*/
if ( pBt.autoVacuum && rc == SQLITE_OK )
{
u8 eType = (u8)( pgnoPtrmap != 0 ? PTRMAP_OVERFLOW2 : PTRMAP_OVERFLOW1 );
ptrmapPut( pBt, pgnoOvfl, eType, pgnoPtrmap, ref rc );
if ( rc != 0 )
{
releasePage( pOvfl );
}
}
#endif
if ( rc != 0 )
{
releasePage( pToRelease );
return rc;
}
/* If pToRelease is not zero than pPrior points into the data area
** of pToRelease. Make sure pToRelease is still writeable. */
Debug.Assert( pToRelease == null || sqlite3PagerIswriteable( pToRelease.pDbPage ) );
/* If pPrior is part of the data area of pPage, then make sure pPage
** is still writeable */
// TODO -- Determine if the following Assert is needed under c#
//Debug.Assert( pPrior < pPage.aData || pPrior >= &pPage.aData[pBt.pageSize]
// || sqlite3PagerIswriteable(pPage.pDbPage) );
sqlite3Put4byte( pPrior, pPriorIndex, pgnoOvfl );
releasePage( pToRelease );
pToRelease = pOvfl;
pPrior = pOvfl.aData;
pPriorIndex = 0;
sqlite3Put4byte( pPrior, 0 );
pPayload = pOvfl.aData;
pPayloadIndex = 4; //&pOvfl.aData[4];
spaceLeft = (int)pBt.usableSize - 4;
}
n = nPayload;
if ( n > spaceLeft )
n = spaceLeft;
/* If pToRelease is not zero than pPayload points into the data area
** of pToRelease. Make sure pToRelease is still writeable. */
Debug.Assert( pToRelease == null || sqlite3PagerIswriteable( pToRelease.pDbPage ) );
/* If pPayload is part of the data area of pPage, then make sure pPage
** is still writeable */
// TODO -- Determine if the following Assert is needed under c#
//Debug.Assert( pPayload < pPage.aData || pPayload >= &pPage.aData[pBt.pageSize]
// || sqlite3PagerIswriteable(pPage.pDbPage) );
if ( nSrc > 0 )
{
if ( n > nSrc )
n = nSrc;
Debug.Assert( pSrc != null );
Buffer.BlockCopy( pSrc, pSrcIndex, pPayload, pPayloadIndex, n );//memcpy(pPayload, pSrc, n);
}
else
{
byte[] pZeroBlob = sqlite3Malloc( n ); // memset(pPayload, 0, n);
Buffer.BlockCopy( pZeroBlob, 0, pPayload, pPayloadIndex, n );
}
nPayload -= n;
pPayloadIndex += n;// pPayload += n;
pSrcIndex += n;// pSrc += n;
nSrc -= n;
spaceLeft -= n;
if ( nSrc == 0 )
{
nSrc = nData;
pSrc = pData;
}
}
releasePage( pToRelease );
return SQLITE_OK;
}
/*
** Remove the i-th cell from pPage. This routine effects pPage only.
** The cell content is not freed or deallocated. It is assumed that
** the cell content has been copied someplace else. This routine just
** removes the reference to the cell from pPage.
**
** "sz" must be the number of bytes in the cell.
*/
static void dropCell( MemPage pPage, int idx, int sz, ref int pRC )
{
u32 pc; /* Offset to cell content of cell being deleted */
u8[] data; /* pPage.aData */
int ptr; /* Used to move bytes around within data[] */
int endPtr; /* End of loop */
int rc; /* The return code */
int hdr; /* Beginning of the header. 0 most pages. 100 page 1 */
if ( pRC != 0 )
return;
Debug.Assert( idx >= 0 && idx < pPage.nCell );
#if SQLITE_DEBUG
Debug.Assert( sz == cellSize( pPage, idx ) );
#endif
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
data = pPage.aData;
ptr = pPage.cellOffset + 2 * idx; //ptr = &data[pPage.cellOffset + 2 * idx];
pc = (u32)get2byte( data, ptr );
hdr = pPage.hdrOffset;
testcase( pc == get2byte( data, hdr + 5 ) );
testcase( pc + sz == pPage.pBt.usableSize );
if ( pc < (u32)get2byte( data, hdr + 5 ) || pc + sz > pPage.pBt.usableSize )
{
pRC = SQLITE_CORRUPT_BKPT();
return;
}
rc = freeSpace( pPage, pc, sz );
if ( rc != 0 )
{
pRC = rc;
return;
}
//endPtr = &data[pPage->cellOffset + 2*pPage->nCell - 2];
//assert( (SQLITE_PTR_TO_INT(ptr)&1)==0 ); /* ptr is always 2-byte aligned */
//while( ptr<endPtr ){
// *(u16*)ptr = *(u16*)&ptr[2];
// ptr += 2;
Buffer.BlockCopy( data, ptr + 2, data, ptr, ( pPage.nCell - 1 - idx ) * 2 );
pPage.nCell--;
data[pPage.hdrOffset + 3] = (byte)( pPage.nCell >> 8 );
data[pPage.hdrOffset + 4] = (byte)( pPage.nCell ); //put2byte( data, hdr + 3, pPage.nCell );
pPage.nFree += 2;
}
/*
** Insert a new cell on pPage at cell index "i". pCell points to the
** content of the cell.
**
** If the cell content will fit on the page, then put it there. If it
** will not fit, then make a copy of the cell content into pTemp if
** pTemp is not null. Regardless of pTemp, allocate a new entry
** in pPage.aOvfl[] and make it point to the cell content (either
** in pTemp or the original pCell) and also record its index.
** Allocating a new entry in pPage.aCell[] implies that
** pPage.nOverflow is incremented.
**
** If nSkip is non-zero, then do not copy the first nSkip bytes of the
** cell. The caller will overwrite them after this function returns. If
** nSkip is non-zero, then pCell may not point to an invalid memory location
** (but pCell+nSkip is always valid).
*/
static void insertCell(
MemPage pPage, /* Page into which we are copying */
int i, /* New cell becomes the i-th cell of the page */
u8[] pCell, /* Content of the new cell */
int sz, /* Bytes of content in pCell */
u8[] pTemp, /* Temp storage space for pCell, if needed */
Pgno iChild, /* If non-zero, replace first 4 bytes with this value */
ref int pRC /* Read and write return code from here */
)
{
int idx = 0; /* Where to write new cell content in data[] */
int j; /* Loop counter */
int end; /* First byte past the last cell pointer in data[] */
int ins; /* Index in data[] where new cell pointer is inserted */
int cellOffset; /* Address of first cell pointer in data[] */
u8[] data; /* The content of the whole page */
u8 ptr; /* Used for moving information around in data[] */
u8 endPtr; /* End of the loop */
int nSkip = ( iChild != 0 ? 4 : 0 );
if ( pRC != 0 )
return;
Debug.Assert( i >= 0 && i <= pPage.nCell + pPage.nOverflow );
Debug.Assert( pPage.nCell <= MX_CELL( pPage.pBt ) && MX_CELL( pPage.pBt ) <= 10921 );
Debug.Assert( pPage.nOverflow <= ArraySize( pPage.aOvfl ) );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
/* The cell should normally be sized correctly. However, when moving a
** malformed cell from a leaf page to an interior page, if the cell size
** wanted to be less than 4 but got rounded up to 4 on the leaf, then size
** might be less than 8 (leaf-size + pointer) on the interior node. Hence
** the term after the || in the following assert(). */
Debug.Assert( sz == cellSizePtr( pPage, pCell ) || ( sz == 8 && iChild > 0 ) );
if ( pPage.nOverflow != 0 || sz + 2 > pPage.nFree )
{
if ( pTemp != null )
{
Buffer.BlockCopy( pCell, nSkip, pTemp, nSkip, sz - nSkip );//memcpy(pTemp+nSkip, pCell+nSkip, sz-nSkip);
pCell = pTemp;
}
if ( iChild != 0 )
{
sqlite3Put4byte( pCell, iChild );
}
j = pPage.nOverflow++;
Debug.Assert( j < pPage.aOvfl.Length );//(int)(sizeof(pPage.aOvfl)/sizeof(pPage.aOvfl[0])) );
pPage.aOvfl[j].pCell = pCell;
pPage.aOvfl[j].idx = (u16)i;
}
else
{
int rc = sqlite3PagerWrite( pPage.pDbPage );
if ( rc != SQLITE_OK )
{
pRC = rc;
return;
}
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
data = pPage.aData;
cellOffset = pPage.cellOffset;
end = cellOffset + 2 * pPage.nCell;
ins = cellOffset + 2 * i;
rc = allocateSpace( pPage, sz, ref idx );
if ( rc != 0 )
{
pRC = rc;
return;
}
/* The allocateSpace() routine guarantees the following two properties
** if it returns success */
Debug.Assert( idx >= end + 2 );
Debug.Assert( idx + sz <= (int)pPage.pBt.usableSize );
pPage.nCell++;
pPage.nFree -= (u16)( 2 + sz );
Buffer.BlockCopy( pCell, nSkip, data, idx + nSkip, sz - nSkip ); //memcpy( data[idx + nSkip], pCell + nSkip, sz - nSkip );
if ( iChild != 0 )
{
sqlite3Put4byte( data, idx, iChild );
}
//ptr = &data[end];
//endPtr = &data[ins];
//assert( ( SQLITE_PTR_TO_INT( ptr ) & 1 ) == 0 ); /* ptr is always 2-byte aligned */
//while ( ptr > endPtr )
//{
// *(u16*)ptr = *(u16*)&ptr[-2];
// ptr -= 2;
//}
for ( j = end; j > ins; j -= 2 )
{
data[j + 0] = data[j - 2];
data[j + 1] = data[j - 1];
}
put2byte( data, ins, idx );
put2byte( data, pPage.hdrOffset + 3, pPage.nCell );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pPage.pBt.autoVacuum )
{
/* The cell may contain a pointer to an overflow page. If so, write
** the entry for the overflow page into the pointer map.
*/
ptrmapPutOvflPtr( pPage, pCell, ref pRC );
}
#endif
}
}
/*
** Add a list of cells to a page. The page should be initially empty.
** The cells are guaranteed to fit on the page.
*/
static void assemblePage(
MemPage pPage, /* The page to be assemblied */
int nCell, /* The number of cells to add to this page */
u8[] apCell, /* Pointer to a single the cell bodies */
int[] aSize /* Sizes of the cells bodie*/
)
{
int i; /* Loop counter */
int pCellptr; /* Address of next cell pointer */
int cellbody; /* Address of next cell body */
byte[] data = pPage.aData; /* Pointer to data for pPage */
int hdr = pPage.hdrOffset; /* Offset of header on pPage */
int nUsable = (int)pPage.pBt.usableSize; /* Usable size of page */
Debug.Assert( pPage.nOverflow == 0 );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( nCell >= 0 && nCell <= (int)MX_CELL( pPage.pBt )
&& (int)MX_CELL( pPage.pBt ) <= 10921 );
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
/* Check that the page has just been zeroed by zeroPage() */
Debug.Assert( pPage.nCell == 0 );
Debug.Assert( get2byteNotZero( data, hdr + 5 ) == nUsable );
pCellptr = pPage.cellOffset + nCell * 2; //data[pPage.cellOffset + nCell * 2];
cellbody = nUsable;
for ( i = nCell - 1; i >= 0; i-- )
{
u16 sz = (u16)aSize[i];
pCellptr -= 2;
cellbody -= sz;
put2byte( data, pCellptr, cellbody );
Buffer.BlockCopy( apCell, 0, data, cellbody, sz );// memcpy(&data[cellbody], apCell[i], sz);
}
put2byte( data, hdr + 3, nCell );
put2byte( data, hdr + 5, cellbody );
pPage.nFree -= (u16)( nCell * 2 + nUsable - cellbody );
pPage.nCell = (u16)nCell;
}
static void assemblePage(
MemPage pPage, /* The page to be assemblied */
int nCell, /* The number of cells to add to this page */
u8[][] apCell, /* Pointers to cell bodies */
u16[] aSize, /* Sizes of the cells */
int offset /* Offset into the cell bodies, for c# */
)
{
int i; /* Loop counter */
int pCellptr; /* Address of next cell pointer */
int cellbody; /* Address of next cell body */
byte[] data = pPage.aData; /* Pointer to data for pPage */
int hdr = pPage.hdrOffset; /* Offset of header on pPage */
int nUsable = (int)pPage.pBt.usableSize; /* Usable size of page */
Debug.Assert( pPage.nOverflow == 0 );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( nCell >= 0 && nCell <= MX_CELL( pPage.pBt ) && MX_CELL( pPage.pBt ) <= 5460 );
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
/* Check that the page has just been zeroed by zeroPage() */
Debug.Assert( pPage.nCell == 0 );
Debug.Assert( get2byte( data, hdr + 5 ) == nUsable );
pCellptr = pPage.cellOffset + nCell * 2; //data[pPage.cellOffset + nCell * 2];
cellbody = nUsable;
for ( i = nCell - 1; i >= 0; i-- )
{
pCellptr -= 2;
cellbody -= aSize[i + offset];
put2byte( data, pCellptr, cellbody );
Buffer.BlockCopy( apCell[offset + i], 0, data, cellbody, aSize[i + offset] );// memcpy(&data[cellbody], apCell[i], aSize[i]);
}
put2byte( data, hdr + 3, nCell );
put2byte( data, hdr + 5, cellbody );
pPage.nFree -= (u16)( nCell * 2 + nUsable - cellbody );
pPage.nCell = (u16)nCell;
}
static void assemblePage(
MemPage pPage, /* The page to be assemblied */
int nCell, /* The number of cells to add to this page */
u8[] apCell, /* Pointers to cell bodies */
u16[] aSize /* Sizes of the cells */
)
{
int i; /* Loop counter */
int pCellptr; /* Address of next cell pointer */
int cellbody; /* Address of next cell body */
u8[] data = pPage.aData; /* Pointer to data for pPage */
int hdr = pPage.hdrOffset; /* Offset of header on pPage */
int nUsable = (int)pPage.pBt.usableSize; /* Usable size of page */
Debug.Assert( pPage.nOverflow == 0 );
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( nCell >= 0 && nCell <= MX_CELL( pPage.pBt ) && MX_CELL( pPage.pBt ) <= 5460 );
Debug.Assert( sqlite3PagerIswriteable( pPage.pDbPage ) );
/* Check that the page has just been zeroed by zeroPage() */
Debug.Assert( pPage.nCell == 0 );
Debug.Assert( get2byte( data, hdr + 5 ) == nUsable );
pCellptr = pPage.cellOffset + nCell * 2; //&data[pPage.cellOffset + nCell * 2];
cellbody = nUsable;
for ( i = nCell - 1; i >= 0; i-- )
{
pCellptr -= 2;
cellbody -= aSize[i];
put2byte( data, pCellptr, cellbody );
Buffer.BlockCopy( apCell, 0, data, cellbody, aSize[i] );//memcpy( data[cellbody], apCell[i], aSize[i] );
}
put2byte( data, hdr + 3, nCell );
put2byte( data, hdr + 5, cellbody );
pPage.nFree -= (u16)( nCell * 2 + nUsable - cellbody );
pPage.nCell = (u16)nCell;
}
/*
** The following parameters determine how many adjacent pages get involved
** in a balancing operation. NN is the number of neighbors on either side
** of the page that participate in the balancing operation. NB is the
** total number of pages that participate, including the target page and
** NN neighbors on either side.
**
** The minimum value of NN is 1 (of course). Increasing NN above 1
** (to 2 or 3) gives a modest improvement in SELECT and DELETE performance
** in exchange for a larger degradation in INSERT and UPDATE performance.
** The value of NN appears to give the best results overall.
*/
static int NN = 1; /* Number of neighbors on either side of pPage */
static int NB = ( NN * 2 + 1 ); /* Total pages involved in the balance */
#if !SQLITE_OMIT_QUICKBALANCE
/*
** This version of balance() handles the common special case where
** a new entry is being inserted on the extreme right-end of the
** tree, in other words, when the new entry will become the largest
** entry in the tree.
**
** Instead of trying to balance the 3 right-most leaf pages, just add
** a new page to the right-hand side and put the one new entry in
** that page. This leaves the right side of the tree somewhat
** unbalanced. But odds are that we will be inserting new entries
** at the end soon afterwards so the nearly empty page will quickly
** fill up. On average.
**
** pPage is the leaf page which is the right-most page in the tree.
** pParent is its parent. pPage must have a single overflow entry
** which is also the right-most entry on the page.
**
** The pSpace buffer is used to store a temporary copy of the divider
** cell that will be inserted into pParent. Such a cell consists of a 4
** byte page number followed by a variable length integer. In other
** words, at most 13 bytes. Hence the pSpace buffer must be at
** least 13 bytes in size.
*/
static int balance_quick( MemPage pParent, MemPage pPage, u8[] pSpace )
{
BtShared pBt = pPage.pBt; /* B-Tree Database */
MemPage pNew = new MemPage();/* Newly allocated page */
int rc; /* Return Code */
Pgno pgnoNew = 0; /* Page number of pNew */
Debug.Assert( sqlite3_mutex_held( pPage.pBt.mutex ) );
Debug.Assert( sqlite3PagerIswriteable( pParent.pDbPage ) );
Debug.Assert( pPage.nOverflow == 1 );
/* This error condition is now caught prior to reaching this function */
if ( pPage.nCell <= 0 )
return SQLITE_CORRUPT_BKPT();
/* Allocate a new page. This page will become the right-sibling of
** pPage. Make the parent page writable, so that the new divider cell
** may be inserted. If both these operations are successful, proceed.
*/
rc = allocateBtreePage( pBt, ref pNew, ref pgnoNew, 0, 0 );
if ( rc == SQLITE_OK )
{
int pOut = 4;//u8 pOut = &pSpace[4];
u8[] pCell = pPage.aOvfl[0].pCell;
int[] szCell = new int[1];
szCell[0] = cellSizePtr( pPage, pCell );
int pStop;
Debug.Assert( sqlite3PagerIswriteable( pNew.pDbPage ) );
Debug.Assert( pPage.aData[0] == ( PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF ) );
zeroPage( pNew, PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF );
assemblePage( pNew, 1, pCell, szCell );
/* If this is an auto-vacuum database, update the pointer map
** with entries for the new page, and any pointer from the
** cell on the page to an overflow page. If either of these
** operations fails, the return code is set, but the contents
** of the parent page are still manipulated by thh code below.
** That is Ok, at this point the parent page is guaranteed to
** be marked as dirty. Returning an error code will cause a
** rollback, undoing any changes made to the parent page.
*/
#if !SQLITE_OMIT_AUTOVACUUM // if ( ISAUTOVACUUM )
if ( pBt.autoVacuum )
#else
if (false)
#endif
{
ptrmapPut( pBt, pgnoNew, PTRMAP_BTREE, pParent.pgno, ref rc );
if ( szCell[0] > pNew.minLocal )
{
ptrmapPutOvflPtr( pNew, pCell, ref rc );
}
}
/* Create a divider cell to insert into pParent. The divider cell
** consists of a 4-byte page number (the page number of pPage) and
** a variable length key value (which must be the same value as the
** largest key on pPage).
**
** To find the largest key value on pPage, first find the right-most
** cell on pPage. The first two fields of this cell are the
** record-length (a variable length integer at most 32-bits in size)
** and the key value (a variable length integer, may have any value).
** The first of the while(...) loops below skips over the record-length
** field. The second while(...) loop copies the key value from the
** cell on pPage into the pSpace buffer.
*/
int iCell = findCell( pPage, pPage.nCell - 1 ); //pCell = findCell( pPage, pPage.nCell - 1 );
pCell = pPage.aData;
int _pCell = iCell;
pStop = _pCell + 9; //pStop = &pCell[9];
while ( ( ( pCell[_pCell++] ) & 0x80 ) != 0 && _pCell < pStop )
; //while ( ( *( pCell++ ) & 0x80 ) && pCell < pStop ) ;
pStop = _pCell + 9;//pStop = &pCell[9];
while ( ( ( pSpace[pOut++] = pCell[_pCell++] ) & 0x80 ) != 0 && _pCell < pStop )
; //while ( ( ( *( pOut++ ) = *( pCell++ ) ) & 0x80 ) && pCell < pStop ) ;
/* Insert the new divider cell into pParent. */
insertCell( pParent, pParent.nCell, pSpace, pOut, //(int)(pOut-pSpace),
null, pPage.pgno, ref rc );
/* Set the right-child pointer of pParent to point to the new page. */
sqlite3Put4byte( pParent.aData, pParent.hdrOffset + 8, pgnoNew );
/* Release the reference to the new page. */
releasePage( pNew );
}
return rc;
}
#endif //* SQLITE_OMIT_QUICKBALANCE */
#if FALSE
/*
** This function does not contribute anything to the operation of SQLite.
** it is sometimes activated temporarily while debugging code responsible
** for setting pointer-map entries.
*/
static int ptrmapCheckPages(MemPage **apPage, int nPage){
int i, j;
for(i=0; i<nPage; i++){
Pgno n;
u8 e;
MemPage pPage = apPage[i];
BtShared pBt = pPage.pBt;
Debug.Assert( pPage.isInit!=0 );
for(j=0; j<pPage.nCell; j++){
CellInfo info;
u8 *z;
z = findCell(pPage, j);
btreeParseCellPtr(pPage, z, info);
if( info.iOverflow ){
Pgno ovfl = sqlite3Get4byte(z[info.iOverflow]);
ptrmapGet(pBt, ovfl, ref e, ref n);
Debug.Assert( n==pPage.pgno && e==PTRMAP_OVERFLOW1 );
}
if( 0==pPage.leaf ){
Pgno child = sqlite3Get4byte(z);
ptrmapGet(pBt, child, ref e, ref n);
Debug.Assert( n==pPage.pgno && e==PTRMAP_BTREE );
}
}
if( 0==pPage.leaf ){
Pgno child = sqlite3Get4byte(pPage.aData,pPage.hdrOffset+8]);
ptrmapGet(pBt, child, ref e, ref n);
Debug.Assert( n==pPage.pgno && e==PTRMAP_BTREE );
}
}
return 1;
}
#endif
/*
** This function is used to copy the contents of the b-tree node stored
** on page pFrom to page pTo. If page pFrom was not a leaf page, then
** the pointer-map entries for each child page are updated so that the
** parent page stored in the pointer map is page pTo. If pFrom contained
** any cells with overflow page pointers, then the corresponding pointer
** map entries are also updated so that the parent page is page pTo.
**
** If pFrom is currently carrying any overflow cells (entries in the
** MemPage.aOvfl[] array), they are not copied to pTo.
**
** Before returning, page pTo is reinitialized using btreeInitPage().
**
** The performance of this function is not critical. It is only used by
** the balance_shallower() and balance_deeper() procedures, neither of
** which are called often under normal circumstances.
*/
static void copyNodeContent( MemPage pFrom, MemPage pTo, ref int pRC )
{
if ( ( pRC ) == SQLITE_OK )
{
BtShared pBt = pFrom.pBt;
u8[] aFrom = pFrom.aData;
u8[] aTo = pTo.aData;
int iFromHdr = pFrom.hdrOffset;
int iToHdr = ( ( pTo.pgno == 1 ) ? 100 : 0 );
int rc;
int iData;
Debug.Assert( pFrom.isInit != 0 );
Debug.Assert( pFrom.nFree >= iToHdr );
Debug.Assert( get2byte( aFrom, iFromHdr + 5 ) <= (int)pBt.usableSize );
/* Copy the b-tree node content from page pFrom to page pTo. */
iData = get2byte( aFrom, iFromHdr + 5 );
Buffer.BlockCopy( aFrom, iData, aTo, iData, (int)pBt.usableSize - iData );//memcpy(aTo[iData], ref aFrom[iData], pBt.usableSize-iData);
Buffer.BlockCopy( aFrom, iFromHdr, aTo, iToHdr, pFrom.cellOffset + 2 * pFrom.nCell );//memcpy(aTo[iToHdr], ref aFrom[iFromHdr], pFrom.cellOffset + 2*pFrom.nCell);
/* Reinitialize page pTo so that the contents of the MemPage structure
** match the new data. The initialization of pTo can actually fail under
** fairly obscure circumstances, even though it is a copy of initialized
** page pFrom.
*/
pTo.isInit = 0;
rc = btreeInitPage( pTo );
if ( rc != SQLITE_OK )
{
pRC = rc;
return;
}
/* If this is an auto-vacuum database, update the pointer-map entries
** for any b-tree or overflow pages that pTo now contains the pointers to.
*/
#if !SQLITE_OMIT_AUTOVACUUM // if ( ISAUTOVACUUM )
if ( pBt.autoVacuum )
#else
if (false)
#endif
{
pRC = setChildPtrmaps( pTo );
}
}
}
/*
** This routine redistributes cells on the iParentIdx'th child of pParent
** (hereafter "the page") and up to 2 siblings so that all pages have about the
** same amount of free space. Usually a single sibling on either side of the
** page are used in the balancing, though both siblings might come from one
** side if the page is the first or last child of its parent. If the page
** has fewer than 2 siblings (something which can only happen if the page
** is a root page or a child of a root page) then all available siblings
** participate in the balancing.
**
** The number of siblings of the page might be increased or decreased by
** one or two in an effort to keep pages nearly full but not over full.
**
** Note that when this routine is called, some of the cells on the page
** might not actually be stored in MemPage.aData[]. This can happen
** if the page is overfull. This routine ensures that all cells allocated
** to the page and its siblings fit into MemPage.aData[] before returning.
**
** In the course of balancing the page and its siblings, cells may be
** inserted into or removed from the parent page (pParent). Doing so
** may cause the parent page to become overfull or underfull. If this
** happens, it is the responsibility of the caller to invoke the correct
** balancing routine to fix this problem (see the balance() routine).
**
** If this routine fails for any reason, it might leave the database
** in a corrupted state. So if this routine fails, the database should
** be rolled back.
**
** The third argument to this function, aOvflSpace, is a pointer to a
** buffer big enough to hold one page. If while inserting cells into the parent
** page (pParent) the parent page becomes overfull, this buffer is
** used to store the parent's overflow cells. Because this function inserts
** a maximum of four divider cells into the parent page, and the maximum
** size of a cell stored within an internal node is always less than 1/4
** of the page-size, the aOvflSpace[] buffer is guaranteed to be large
** enough for all overflow cells.
**
** If aOvflSpace is set to a null pointer, this function returns
** SQLITE_NOMEM.
*/
// under C#; Try to reuse Memory
static int balance_nonroot(
MemPage pParent, /* Parent page of siblings being balanced */
int iParentIdx, /* Index of "the page" in pParent */
u8[] aOvflSpace, /* page-size bytes of space for parent ovfl */
int isRoot /* True if pParent is a root-page */
)
{
MemPage[] apOld = new MemPage[NB]; /* pPage and up to two siblings */
MemPage[] apCopy = new MemPage[NB]; /* Private copies of apOld[] pages */
MemPage[] apNew = new MemPage[NB + 2];/* pPage and up to NB siblings after balancing */
int[] apDiv = new int[NB - 1]; /* Divider cells in pParent */
int[] cntNew = new int[NB + 2]; /* Index in aCell[] of cell after i-th page */
int[] szNew = new int[NB + 2]; /* Combined size of cells place on i-th page */
u16[] szCell = new u16[1]; /* Local size of all cells in apCell[] */
BtShared pBt; /* The whole database */
int nCell = 0; /* Number of cells in apCell[] */
int nMaxCells = 0; /* Allocated size of apCell, szCell, aFrom. */
int nNew = 0; /* Number of pages in apNew[] */
int nOld; /* Number of pages in apOld[] */
int i, j, k; /* Loop counters */
int nxDiv; /* Next divider slot in pParent.aCell[] */
int rc = SQLITE_OK; /* The return code */
u16 leafCorrection; /* 4 if pPage is a leaf. 0 if not */
int leafData; /* True if pPage is a leaf of a LEAFDATA tree */
int usableSpace; /* Bytes in pPage beyond the header */
int pageFlags; /* Value of pPage.aData[0] */
int subtotal; /* Subtotal of bytes in cells on one page */
//int iSpace1 = 0; /* First unused byte of aSpace1[] */
int iOvflSpace = 0; /* First unused byte of aOvflSpace[] */
int szScratch; /* Size of scratch memory requested */
int pRight; /* Location in parent of right-sibling pointer */
u8[][] apCell = null; /* All cells begin balanced */
//u16[] szCell; /* Local size of all cells in apCell[] */
//u8[] aSpace1; /* Space for copies of dividers cells */
Pgno pgno; /* Temp var to store a page number in */
pBt = pParent.pBt;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
Debug.Assert( sqlite3PagerIswriteable( pParent.pDbPage ) );
#if FALSE
TRACE("BALANCE: begin page %d child of %d\n", pPage.pgno, pParent.pgno);
#endif
/* At this point pParent may have at most one overflow cell. And if
** this overflow cell is present, it must be the cell with
** index iParentIdx. This scenario comes about when this function
** is called (indirectly) from sqlite3BtreeDelete().
*/
Debug.Assert( pParent.nOverflow == 0 || pParent.nOverflow == 1 );
Debug.Assert( pParent.nOverflow == 0 || pParent.aOvfl[0].idx == iParentIdx );
//if( !aOvflSpace ){
// return SQLITE_NOMEM;
//}
/* Find the sibling pages to balance. Also locate the cells in pParent
** that divide the siblings. An attempt is made to find NN siblings on
** either side of pPage. More siblings are taken from one side, however,
** if there are fewer than NN siblings on the other side. If pParent
** has NB or fewer children then all children of pParent are taken.
**
** This loop also drops the divider cells from the parent page. This
** way, the remainder of the function does not have to deal with any
** overflow cells in the parent page, since if any existed they will
** have already been removed.
*/
i = pParent.nOverflow + pParent.nCell;
if ( i < 2 )
{
nxDiv = 0;
nOld = i + 1;
}
else
{
nOld = 3;
if ( iParentIdx == 0 )
{
nxDiv = 0;
}
else if ( iParentIdx == i )
{
nxDiv = i - 2;
}
else
{
nxDiv = iParentIdx - 1;
}
i = 2;
}
if ( ( i + nxDiv - pParent.nOverflow ) == pParent.nCell )
{
pRight = pParent.hdrOffset + 8; //&pParent.aData[pParent.hdrOffset + 8];
}
else
{
pRight = findCell( pParent, i + nxDiv - pParent.nOverflow );
}
pgno = sqlite3Get4byte( pParent.aData, pRight );
while ( true )
{
rc = getAndInitPage( pBt, pgno, ref apOld[i] );
if ( rc != 0 )
{
//memset(apOld, 0, (i+1)*sizeof(MemPage*));
goto balance_cleanup;
}
nMaxCells += 1 + apOld[i].nCell + apOld[i].nOverflow;
if ( ( i-- ) == 0 )
break;
if ( i + nxDiv == pParent.aOvfl[0].idx && pParent.nOverflow != 0 )
{
apDiv[i] = 0;// = pParent.aOvfl[0].pCell;
pgno = sqlite3Get4byte( pParent.aOvfl[0].pCell, apDiv[i] );
szNew[i] = cellSizePtr( pParent, apDiv[i] );
pParent.nOverflow = 0;
}
else
{
apDiv[i] = findCell( pParent, i + nxDiv - pParent.nOverflow );
pgno = sqlite3Get4byte( pParent.aData, apDiv[i] );
szNew[i] = cellSizePtr( pParent, apDiv[i] );
/* Drop the cell from the parent page. apDiv[i] still points to
** the cell within the parent, even though it has been dropped.
** This is safe because dropping a cell only overwrites the first
** four bytes of it, and this function does not need the first
** four bytes of the divider cell. So the pointer is safe to use
** later on.
**
** Unless SQLite is compiled in secure-delete mode. In this case,
** the dropCell() routine will overwrite the entire cell with zeroes.
** In this case, temporarily copy the cell into the aOvflSpace[]
** buffer. It will be copied out again as soon as the aSpace[] buffer
** is allocated. */
//if (pBt.secureDelete)
//{
// int iOff = (int)(apDiv[i]) - (int)(pParent.aData); //SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent.aData);
// if( (iOff+szNew[i])>(int)pBt->usableSize )
// {
// rc = SQLITE_CORRUPT_BKPT();
// Array.Clear(apOld[0].aData,0,apOld[0].aData.Length); //memset(apOld, 0, (i + 1) * sizeof(MemPage*));
// goto balance_cleanup;
// }
// else
// {
// memcpy(&aOvflSpace[iOff], apDiv[i], szNew[i]);
// apDiv[i] = &aOvflSpace[apDiv[i] - pParent.aData];
// }
//}
dropCell( pParent, i + nxDiv - pParent.nOverflow, szNew[i], ref rc );
}
}
/* Make nMaxCells a multiple of 4 in order to preserve 8-byte
** alignment */
nMaxCells = ( nMaxCells + 3 ) & ~3;
/*
** Allocate space for memory structures
*/
//k = pBt.pageSize + ROUND8(sizeof(MemPage));
//szScratch =
// nMaxCells*sizeof(u8*) /* apCell */
// + nMaxCells*sizeof(u16) /* szCell */
// + pBt.pageSize /* aSpace1 */
// + k*nOld; /* Page copies (apCopy) */
apCell = sqlite3ScratchMalloc( apCell, nMaxCells );
//if( apCell==null ){
// rc = SQLITE_NOMEM;
// goto balance_cleanup;
//}
if ( szCell.Length < nMaxCells )
Array.Resize( ref szCell, nMaxCells ); //(u16*)&apCell[nMaxCells];
//aSpace1 = new byte[pBt.pageSize * (nMaxCells)];// aSpace1 = (u8*)&szCell[nMaxCells];
//Debug.Assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );
/*
** Load pointers to all cells on sibling pages and the divider cells
** into the local apCell[] array. Make copies of the divider cells
** into space obtained from aSpace1[] and remove the the divider Cells
** from pParent.
**
** If the siblings are on leaf pages, then the child pointers of the
** divider cells are stripped from the cells before they are copied
** into aSpace1[]. In this way, all cells in apCell[] are without
** child pointers. If siblings are not leaves, then all cell in
** apCell[] include child pointers. Either way, all cells in apCell[]
** are alike.
**
** leafCorrection: 4 if pPage is a leaf. 0 if pPage is not a leaf.
** leafData: 1 if pPage holds key+data and pParent holds only keys.
*/
leafCorrection = (u16)( apOld[0].leaf * 4 );
leafData = apOld[0].hasData;
for ( i = 0; i < nOld; i++ )
{
int limit;
/* Before doing anything else, take a copy of the i'th original sibling
** The rest of this function will use data from the copies rather
** that the original pages since the original pages will be in the
** process of being overwritten. */
//MemPage pOld = apCopy[i] = (MemPage*)&aSpace1[pBt.pageSize + k*i];
//memcpy(pOld, apOld[i], sizeof(MemPage));
//pOld.aData = (void*)&pOld[1];
//memcpy(pOld.aData, apOld[i].aData, pBt.pageSize);
MemPage pOld = apCopy[i] = apOld[i].Copy();
limit = pOld.nCell + pOld.nOverflow;
if( pOld.nOverflow>0 || true){
for ( j = 0; j < limit; j++ )
{
Debug.Assert( nCell < nMaxCells );
//apCell[nCell] = findOverflowCell( pOld, j );
//szCell[nCell] = cellSizePtr( pOld, apCell, nCell );
int iFOFC = findOverflowCell( pOld, j );
szCell[nCell] = cellSizePtr( pOld, iFOFC );
// Copy the Data Locally
if ( apCell[nCell] == null )
apCell[nCell] = new u8[szCell[nCell]];
else if ( apCell[nCell].Length < szCell[nCell] )
Array.Resize( ref apCell[nCell], szCell[nCell] );
if ( iFOFC < 0 ) // Overflow Cell
Buffer.BlockCopy( pOld.aOvfl[-( iFOFC + 1 )].pCell, 0, apCell[nCell], 0, szCell[nCell] );
else
Buffer.BlockCopy( pOld.aData, iFOFC, apCell[nCell], 0, szCell[nCell] );
nCell++;
}
}
else
{
u8[] aData = pOld.aData;
u16 maskPage = pOld.maskPage;
u16 cellOffset = pOld.cellOffset;
for ( j = 0; j < limit; j++ )
{
Debugger.Break();
Debug.Assert( nCell < nMaxCells );
apCell[nCell] = findCellv2( aData, maskPage, cellOffset, j );
szCell[nCell] = cellSizePtr( pOld, apCell[nCell] );
nCell++;
}
}
if ( i < nOld - 1 && 0 == leafData )
{
u16 sz = (u16)szNew[i];
byte[] pTemp = sqlite3Malloc( sz + leafCorrection );
Debug.Assert( nCell < nMaxCells );
szCell[nCell] = sz;
//pTemp = &aSpace1[iSpace1];
//iSpace1 += sz;
Debug.Assert( sz <= pBt.maxLocal + 23 );
//Debug.Assert(iSpace1 <= (int)pBt.pageSize);
Buffer.BlockCopy( pParent.aData, apDiv[i], pTemp, 0, sz );//memcpy( pTemp, apDiv[i], sz );
if ( apCell[nCell] == null || apCell[nCell].Length < sz )
Array.Resize( ref apCell[nCell], sz );
Buffer.BlockCopy( pTemp, leafCorrection, apCell[nCell], 0, sz );//apCell[nCell] = pTemp + leafCorrection;
Debug.Assert( leafCorrection == 0 || leafCorrection == 4 );
szCell[nCell] = (u16)( szCell[nCell] - leafCorrection );
if ( 0 == pOld.leaf )
{
Debug.Assert( leafCorrection == 0 );
Debug.Assert( pOld.hdrOffset == 0 );
/* The right pointer of the child page pOld becomes the left
** pointer of the divider cell */
Buffer.BlockCopy( pOld.aData, 8, apCell[nCell], 0, 4 );//memcpy( apCell[nCell], ref pOld.aData[8], 4 );
}
else
{
Debug.Assert( leafCorrection == 4 );
if ( szCell[nCell] < 4 )
{
/* Do not allow any cells smaller than 4 bytes. */
szCell[nCell] = 4;
}
}
nCell++;
}
}
/*
** Figure out the number of pages needed to hold all nCell cells.
** Store this number in "k". Also compute szNew[] which is the total
** size of all cells on the i-th page and cntNew[] which is the index
** in apCell[] of the cell that divides page i from page i+1.
** cntNew[k] should equal nCell.
**
** Values computed by this block:
**
** k: The total number of sibling pages
** szNew[i]: Spaced used on the i-th sibling page.
** cntNew[i]: Index in apCell[] and szCell[] for the first cell to
** the right of the i-th sibling page.
** usableSpace: Number of bytes of space available on each sibling.
**
*/
usableSpace = (int)pBt.usableSize - 12 + leafCorrection;
for ( subtotal = k = i = 0; i < nCell; i++ )
{
Debug.Assert( i < nMaxCells );
subtotal += szCell[i] + 2;
if ( subtotal > usableSpace )
{
szNew[k] = subtotal - szCell[i];
cntNew[k] = i;
if ( leafData != 0 )
{
i--;
}
subtotal = 0;
k++;
if ( k > NB + 1 )
{
rc = SQLITE_CORRUPT_BKPT();
goto balance_cleanup;
}
}
}
szNew[k] = subtotal;
cntNew[k] = nCell;
k++;
/*
** The packing computed by the previous block is biased toward the siblings
** on the left side. The left siblings are always nearly full, while the
** right-most sibling might be nearly empty. This block of code attempts
** to adjust the packing of siblings to get a better balance.
**
** This adjustment is more than an optimization. The packing above might
** be so out of balance as to be illegal. For example, the right-most
** sibling might be completely empty. This adjustment is not optional.
*/
for ( i = k - 1; i > 0; i-- )
{
int szRight = szNew[i]; /* Size of sibling on the right */
int szLeft = szNew[i - 1]; /* Size of sibling on the left */
int r; /* Index of right-most cell in left sibling */
int d; /* Index of first cell to the left of right sibling */
r = cntNew[i - 1] - 1;
d = r + 1 - leafData;
Debug.Assert( d < nMaxCells );
Debug.Assert( r < nMaxCells );
while ( szRight == 0 || szRight + szCell[d] + 2 <= szLeft - ( szCell[r] + 2 ) )
{
szRight += szCell[d] + 2;
szLeft -= szCell[r] + 2;
cntNew[i - 1]--;
r = cntNew[i - 1] - 1;
d = r + 1 - leafData;
}
szNew[i] = szRight;
szNew[i - 1] = szLeft;
}
/* Either we found one or more cells (cntnew[0])>0) or pPage is
** a virtual root page. A virtual root page is when the real root
** page is page 1 and we are the only child of that page.
*/
Debug.Assert( cntNew[0] > 0 || ( pParent.pgno == 1 && pParent.nCell == 0 ) );
TRACE( "BALANCE: old: %d %d %d ",
apOld[0].pgno,
nOld >= 2 ? apOld[1].pgno : 0,
nOld >= 3 ? apOld[2].pgno : 0
);
/*
** Allocate k new pages. Reuse old pages where possible.
*/
if ( apOld[0].pgno <= 1 )
{
rc = SQLITE_CORRUPT_BKPT();
goto balance_cleanup;
}
pageFlags = apOld[0].aData[0];
for ( i = 0; i < k; i++ )
{
MemPage pNew = new MemPage();
if ( i < nOld )
{
pNew = apNew[i] = apOld[i];
apOld[i] = null;
rc = sqlite3PagerWrite( pNew.pDbPage );
nNew++;
if ( rc != 0 )
goto balance_cleanup;
}
else
{
Debug.Assert( i > 0 );
rc = allocateBtreePage( pBt, ref pNew, ref pgno, pgno, 0 );
if ( rc != 0 )
goto balance_cleanup;
apNew[i] = pNew;
nNew++;
/* Set the pointer-map entry for the new sibling page. */
#if !SQLITE_OMIT_AUTOVACUUM // if ( ISAUTOVACUUM )
if ( pBt.autoVacuum )
#else
if (false)
#endif
{
ptrmapPut( pBt, pNew.pgno, PTRMAP_BTREE, pParent.pgno, ref rc );
if ( rc != SQLITE_OK )
{
goto balance_cleanup;
}
}
}
}
/* Free any old pages that were not reused as new pages.
*/
while ( i < nOld )
{
freePage( apOld[i], ref rc );
if ( rc != 0 )
goto balance_cleanup;
releasePage( apOld[i] );
apOld[i] = null;
i++;
}
/*
** Put the new pages in accending order. This helps to
** keep entries in the disk file in order so that a scan
** of the table is a linear scan through the file. That
** in turn helps the operating system to deliver pages
** from the disk more rapidly.
**
** An O(n^2) insertion sort algorithm is used, but since
** n is never more than NB (a small constant), that should
** not be a problem.
**
** When NB==3, this one optimization makes the database
** about 25% faster for large insertions and deletions.
*/
for ( i = 0; i < k - 1; i++ )
{
int minV = (int)apNew[i].pgno;
int minI = i;
for ( j = i + 1; j < k; j++ )
{
if ( apNew[j].pgno < (u32)minV )
{
minI = j;
minV = (int)apNew[j].pgno;
}
}
if ( minI > i )
{
MemPage pT;
pT = apNew[i];
apNew[i] = apNew[minI];
apNew[minI] = pT;
}
}
TRACE( "new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
apNew[0].pgno, szNew[0],
nNew >= 2 ? apNew[1].pgno : 0, nNew >= 2 ? szNew[1] : 0,
nNew >= 3 ? apNew[2].pgno : 0, nNew >= 3 ? szNew[2] : 0,
nNew >= 4 ? apNew[3].pgno : 0, nNew >= 4 ? szNew[3] : 0,
nNew >= 5 ? apNew[4].pgno : 0, nNew >= 5 ? szNew[4] : 0 );
Debug.Assert( sqlite3PagerIswriteable( pParent.pDbPage ) );
sqlite3Put4byte( pParent.aData, pRight, apNew[nNew - 1].pgno );
/*
** Evenly distribute the data in apCell[] across the new pages.
** Insert divider cells into pParent as necessary.
*/
j = 0;
for ( i = 0; i < nNew; i++ )
{
/* Assemble the new sibling page. */
MemPage pNew = apNew[i];
Debug.Assert( j < nMaxCells );
zeroPage( pNew, pageFlags );
assemblePage( pNew, cntNew[i] - j, apCell, szCell, j );
Debug.Assert( pNew.nCell > 0 || ( nNew == 1 && cntNew[0] == 0 ) );
Debug.Assert( pNew.nOverflow == 0 );
j = cntNew[i];
/* If the sibling page assembled above was not the right-most sibling,
** insert a divider cell into the parent page.
*/
Debug.Assert( i < nNew - 1 || j == nCell );
if ( j < nCell )
{
u8[] pCell;
u8[] pTemp;
int sz;
Debug.Assert( j < nMaxCells );
pCell = apCell[j];
sz = szCell[j] + leafCorrection;
pTemp = sqlite3Malloc( sz );//&aOvflSpace[iOvflSpace];
if ( 0 == pNew.leaf )
{
Buffer.BlockCopy( pCell, 0, pNew.aData, 8, 4 );//memcpy( pNew.aData[8], pCell, 4 );
}
else if ( leafData != 0 )
{
/* If the tree is a leaf-data tree, and the siblings are leaves,
** then there is no divider cell in apCell[]. Instead, the divider
** cell consists of the integer key for the right-most cell of
** the sibling-page assembled above only.
*/
CellInfo info = new CellInfo();
j--;
btreeParseCellPtr( pNew, apCell[j], ref info );
pCell = pTemp;
sz = 4 + putVarint( pCell, 4, (u64)info.nKey );
pTemp = null;
}
else
{
//------------ pCell -= 4;
byte[] _pCell_4 = sqlite3Malloc( pCell.Length + 4 );
Buffer.BlockCopy( pCell, 0, _pCell_4, 4, pCell.Length );
pCell = _pCell_4;
//
/* Obscure case for non-leaf-data trees: If the cell at pCell was
** previously stored on a leaf node, and its reported size was 4
** bytes, then it may actually be smaller than this
** (see btreeParseCellPtr(), 4 bytes is the minimum size of
** any cell). But it is important to pass the correct size to
** insertCell(), so reparse the cell now.
**
** Note that this can never happen in an SQLite data file, as all
** cells are at least 4 bytes. It only happens in b-trees used
** to evaluate "IN (SELECT ...)" and similar clauses.
*/
if ( szCell[j] == 4 )
{
Debug.Assert( leafCorrection == 4 );
sz = cellSizePtr( pParent, pCell );
}
}
iOvflSpace += sz;
Debug.Assert( sz <= pBt.maxLocal + 23 );
Debug.Assert( iOvflSpace <= (int)pBt.pageSize );
insertCell( pParent, nxDiv, pCell, sz, pTemp, pNew.pgno, ref rc );
if ( rc != SQLITE_OK )
goto balance_cleanup;
Debug.Assert( sqlite3PagerIswriteable( pParent.pDbPage ) );
j++;
nxDiv++;
}
}
Debug.Assert( j == nCell );
Debug.Assert( nOld > 0 );
Debug.Assert( nNew > 0 );
if ( ( pageFlags & PTF_LEAF ) == 0 )
{
Buffer.BlockCopy( apCopy[nOld - 1].aData, 8, apNew[nNew - 1].aData, 8, 4 ); //u8* zChild = &apCopy[nOld - 1].aData[8];
//memcpy( apNew[nNew - 1].aData[8], zChild, 4 );
}
if ( isRoot != 0 && pParent.nCell == 0 && pParent.hdrOffset <= apNew[0].nFree )
{
/* The root page of the b-tree now contains no cells. The only sibling
** page is the right-child of the parent. Copy the contents of the
** child page into the parent, decreasing the overall height of the
** b-tree structure by one. This is described as the "balance-shallower"
** sub-algorithm in some documentation.
**
** If this is an auto-vacuum database, the call to copyNodeContent()
** sets all pointer-map entries corresponding to database image pages
** for which the pointer is stored within the content being copied.
**
** The second Debug.Assert below verifies that the child page is defragmented
** (it must be, as it was just reconstructed using assemblePage()). This
** is important if the parent page happens to be page 1 of the database
** image. */
Debug.Assert( nNew == 1 );
Debug.Assert( apNew[0].nFree ==
( get2byte( apNew[0].aData, 5 ) - apNew[0].cellOffset - apNew[0].nCell * 2 )
);
copyNodeContent( apNew[0], pParent, ref rc );
freePage( apNew[0], ref rc );
}
else
#if !SQLITE_OMIT_AUTOVACUUM // if ( ISAUTOVACUUM )
if ( pBt.autoVacuum )
#else
if (false)
#endif
{
/* Fix the pointer-map entries for all the cells that were shifted around.
** There are several different types of pointer-map entries that need to
** be dealt with by this routine. Some of these have been set already, but
** many have not. The following is a summary:
**
** 1) The entries associated with new sibling pages that were not
** siblings when this function was called. These have already
** been set. We don't need to worry about old siblings that were
** moved to the free-list - the freePage() code has taken care
** of those.
**
** 2) The pointer-map entries associated with the first overflow
** page in any overflow chains used by new divider cells. These
** have also already been taken care of by the insertCell() code.
**
** 3) If the sibling pages are not leaves, then the child pages of
** cells stored on the sibling pages may need to be updated.
**
** 4) If the sibling pages are not internal intkey nodes, then any
** overflow pages used by these cells may need to be updated
** (internal intkey nodes never contain pointers to overflow pages).
**
** 5) If the sibling pages are not leaves, then the pointer-map
** entries for the right-child pages of each sibling may need
** to be updated.
**
** Cases 1 and 2 are dealt with above by other code. The next
** block deals with cases 3 and 4 and the one after that, case 5. Since
** setting a pointer map entry is a relatively expensive operation, this
** code only sets pointer map entries for child or overflow pages that have
** actually moved between pages. */
MemPage pNew = apNew[0];
MemPage pOld = apCopy[0];
int nOverflow = pOld.nOverflow;
int iNextOld = pOld.nCell + nOverflow;
int iOverflow = ( nOverflow != 0 ? pOld.aOvfl[0].idx : -1 );
j = 0; /* Current 'old' sibling page */
k = 0; /* Current 'new' sibling page */
for ( i = 0; i < nCell; i++ )
{
int isDivider = 0;
while ( i == iNextOld )
{
/* Cell i is the cell immediately following the last cell on old
** sibling page j. If the siblings are not leaf pages of an
** intkey b-tree, then cell i was a divider cell. */
pOld = apCopy[++j];
iNextOld = i + ( 0 == leafData ? 1 : 0 ) + pOld.nCell + pOld.nOverflow;
if ( pOld.nOverflow != 0 )
{
nOverflow = pOld.nOverflow;
iOverflow = i + ( 0 == leafData ? 1 : 0 ) + pOld.aOvfl[0].idx;
}
isDivider = 0 == leafData ? 1 : 0;
}
Debug.Assert( nOverflow > 0 || iOverflow < i );
Debug.Assert( nOverflow < 2 || pOld.aOvfl[0].idx == pOld.aOvfl[1].idx - 1 );
Debug.Assert( nOverflow < 3 || pOld.aOvfl[1].idx == pOld.aOvfl[2].idx - 1 );
if ( i == iOverflow )
{
isDivider = 1;
if ( ( --nOverflow ) > 0 )
{
iOverflow++;
}
}
if ( i == cntNew[k] )
{
/* Cell i is the cell immediately following the last cell on new
** sibling page k. If the siblings are not leaf pages of an
** intkey b-tree, then cell i is a divider cell. */
pNew = apNew[++k];
if ( 0 == leafData )
continue;
}
Debug.Assert( j < nOld );
Debug.Assert( k < nNew );
/* If the cell was originally divider cell (and is not now) or
** an overflow cell, or if the cell was located on a different sibling
** page before the balancing, then the pointer map entries associated
** with any child or overflow pages need to be updated. */
if ( isDivider != 0 || pOld.pgno != pNew.pgno )
{
if ( 0 == leafCorrection )
{
ptrmapPut( pBt, sqlite3Get4byte( apCell[i] ), PTRMAP_BTREE, pNew.pgno, ref rc );
}
if ( szCell[i] > pNew.minLocal )
{
ptrmapPutOvflPtr( pNew, apCell[i], ref rc );
}
}
}
if ( 0 == leafCorrection )
{
for ( i = 0; i < nNew; i++ )
{
u32 key = sqlite3Get4byte( apNew[i].aData, 8 );
ptrmapPut( pBt, key, PTRMAP_BTREE, apNew[i].pgno, ref rc );
}
}
#if FALSE
/* The ptrmapCheckPages() contains Debug.Assert() statements that verify that
** all pointer map pages are set correctly. This is helpful while
** debugging. This is usually disabled because a corrupt database may
** cause an Debug.Assert() statement to fail. */
ptrmapCheckPages(apNew, nNew);
ptrmapCheckPages(pParent, 1);
#endif
}
Debug.Assert( pParent.isInit != 0 );
TRACE( "BALANCE: finished: old=%d new=%d cells=%d\n",
nOld, nNew, nCell );
/*
** Cleanup before returning.
*/
balance_cleanup:
sqlite3ScratchFree( apCell );
for ( i = 0; i < nOld; i++ )
{
releasePage( apOld[i] );
}
for ( i = 0; i < nNew; i++ )
{
releasePage( apNew[i] );
}
return rc;
}
/*
** This function is called when the root page of a b-tree structure is
** overfull (has one or more overflow pages).
**
** A new child page is allocated and the contents of the current root
** page, including overflow cells, are copied into the child. The root
** page is then overwritten to make it an empty page with the right-child
** pointer pointing to the new page.
**
** Before returning, all pointer-map entries corresponding to pages
** that the new child-page now contains pointers to are updated. The
** entry corresponding to the new right-child pointer of the root
** page is also updated.
**
** If successful, ppChild is set to contain a reference to the child
** page and SQLITE_OK is returned. In this case the caller is required
** to call releasePage() on ppChild exactly once. If an error occurs,
** an error code is returned and ppChild is set to 0.
*/
static int balance_deeper( MemPage pRoot, ref MemPage ppChild )
{
int rc; /* Return value from subprocedures */
MemPage pChild = null; /* Pointer to a new child page */
Pgno pgnoChild = 0; /* Page number of the new child page */
BtShared pBt = pRoot.pBt; /* The BTree */
Debug.Assert( pRoot.nOverflow > 0 );
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
/* Make pRoot, the root page of the b-tree, writable. Allocate a new
** page that will become the new right-child of pPage. Copy the contents
** of the node stored on pRoot into the new child page.
*/
rc = sqlite3PagerWrite( pRoot.pDbPage );
if ( rc == SQLITE_OK )
{
rc = allocateBtreePage( pBt, ref pChild, ref pgnoChild, pRoot.pgno, 0 );
copyNodeContent( pRoot, pChild, ref rc );
#if !SQLITE_OMIT_AUTOVACUUM // if ( ISAUTOVACUUM )
if ( pBt.autoVacuum )
#else
if (false)
#endif
{
ptrmapPut( pBt, pgnoChild, PTRMAP_BTREE, pRoot.pgno, ref rc );
}
}
if ( rc != 0 )
{
ppChild = null;
releasePage( pChild );
return rc;
}
Debug.Assert( sqlite3PagerIswriteable( pChild.pDbPage ) );
Debug.Assert( sqlite3PagerIswriteable( pRoot.pDbPage ) );
Debug.Assert( pChild.nCell == pRoot.nCell );
TRACE( "BALANCE: copy root %d into %d\n", pRoot.pgno, pChild.pgno );
/* Copy the overflow cells from pRoot to pChild */
Array.Copy( pRoot.aOvfl, pChild.aOvfl, pRoot.nOverflow );//memcpy(pChild.aOvfl, pRoot.aOvfl, pRoot.nOverflow*sizeof(pRoot.aOvfl[0]));
pChild.nOverflow = pRoot.nOverflow;
/* Zero the contents of pRoot. Then install pChild as the right-child. */
zeroPage( pRoot, pChild.aData[0] & ~PTF_LEAF );
sqlite3Put4byte( pRoot.aData, pRoot.hdrOffset + 8, pgnoChild );
ppChild = pChild;
return SQLITE_OK;
}
/*
** The page that pCur currently points to has just been modified in
** some way. This function figures out if this modification means the
** tree needs to be balanced, and if so calls the appropriate balancing
** routine. Balancing routines are:
**
** balance_quick()
** balance_deeper()
** balance_nonroot()
*/
static u8[] aBalanceQuickSpace = new u8[13];
static int balance( BtCursor pCur )
{
int rc = SQLITE_OK;
int nMin = (int)pCur.pBt.usableSize * 2 / 3;
//u8[] pFree = null;
#if !NDEBUG || SQLITE_COVERAGE_TEST || DEBUG
int balance_quick_called = 0;//TESTONLY( int balance_quick_called = 0 );
int balance_deeper_called = 0;//TESTONLY( int balance_deeper_called = 0 );
#else
int balance_quick_called = 0;
int balance_deeper_called = 0;
#endif
do
{
int iPage = pCur.iPage;
MemPage pPage = pCur.apPage[iPage];
if ( iPage == 0 )
{
if ( pPage.nOverflow != 0 )
{
/* The root page of the b-tree is overfull. In this case call the
** balance_deeper() function to create a new child for the root-page
** and copy the current contents of the root-page to it. The
** next iteration of the do-loop will balance the child page.
*/
Debug.Assert( ( balance_deeper_called++ ) == 0 );
rc = balance_deeper( pPage, ref pCur.apPage[1] );
if ( rc == SQLITE_OK )
{
pCur.iPage = 1;
pCur.aiIdx[0] = 0;
pCur.aiIdx[1] = 0;
Debug.Assert( pCur.apPage[1].nOverflow != 0 );
}
}
else
{
break;
}
}
else if ( pPage.nOverflow == 0 && pPage.nFree <= nMin )
{
break;
}
else
{
MemPage pParent = pCur.apPage[iPage - 1];
int iIdx = pCur.aiIdx[iPage - 1];
rc = sqlite3PagerWrite( pParent.pDbPage );
if ( rc == SQLITE_OK )
{
#if !SQLITE_OMIT_QUICKBALANCE
if ( pPage.hasData != 0
&& pPage.nOverflow == 1
&& pPage.aOvfl[0].idx == pPage.nCell
&& pParent.pgno != 1
&& pParent.nCell == iIdx
)
{
/* Call balance_quick() to create a new sibling of pPage on which
** to store the overflow cell. balance_quick() inserts a new cell
** into pParent, which may cause pParent overflow. If this
** happens, the next interation of the do-loop will balance pParent
** use either balance_nonroot() or balance_deeper(). Until this
** happens, the overflow cell is stored in the aBalanceQuickSpace[]
** buffer.
**
** The purpose of the following Debug.Assert() is to check that only a
** single call to balance_quick() is made for each call to this
** function. If this were not verified, a subtle bug involving reuse
** of the aBalanceQuickSpace[] might sneak in.
*/
Debug.Assert( ( balance_quick_called++ ) == 0 );
rc = balance_quick( pParent, pPage, aBalanceQuickSpace );
}
else
#endif
{
/* In this case, call balance_nonroot() to redistribute cells
** between pPage and up to 2 of its sibling pages. This involves
** modifying the contents of pParent, which may cause pParent to
** become overfull or underfull. The next iteration of the do-loop
** will balance the parent page to correct this.
**
** If the parent page becomes overfull, the overflow cell or cells
** are stored in the pSpace buffer allocated immediately below.
** A subsequent iteration of the do-loop will deal with this by
** calling balance_nonroot() (balance_deeper() may be called first,
** but it doesn't deal with overflow cells - just moves them to a
** different page). Once this subsequent call to balance_nonroot()
** has completed, it is safe to release the pSpace buffer used by
** the previous call, as the overflow cell data will have been
** copied either into the body of a database page or into the new
** pSpace buffer passed to the latter call to balance_nonroot().
*/
////u8[] pSpace = new u8[pCur.pBt.pageSize];// u8 pSpace = sqlite3PageMalloc( pCur.pBt.pageSize );
rc = balance_nonroot( pParent, iIdx, null, iPage == 1 ? 1 : 0 );
//if (pFree != null)
//{
// /* If pFree is not NULL, it points to the pSpace buffer used
// ** by a previous call to balance_nonroot(). Its contents are
// ** now stored either on real database pages or within the
// ** new pSpace buffer, so it may be safely freed here. */
// sqlite3PageFree(ref pFree);
//}
/* The pSpace buffer will be freed after the next call to
** balance_nonroot(), or just before this function returns, whichever
** comes first. */
//pFree = pSpace;
}
}
pPage.nOverflow = 0;
/* The next iteration of the do-loop balances the parent page. */
releasePage( pPage );
pCur.iPage--;
}
} while ( rc == SQLITE_OK );
//if (pFree != null)
//{
// sqlite3PageFree(ref pFree);
//}
return rc;
}
/*
** Insert a new record into the BTree. The key is given by (pKey,nKey)
** and the data is given by (pData,nData). The cursor is used only to
** define what table the record should be inserted into. The cursor
** is left pointing at a random location.
**
** For an INTKEY table, only the nKey value of the key is used. pKey is
** ignored. For a ZERODATA table, the pData and nData are both ignored.
**
** If the seekResult parameter is non-zero, then a successful call to
** MovetoUnpacked() to seek cursor pCur to (pKey, nKey) has already
** been performed. seekResult is the search result returned (a negative
** number if pCur points at an entry that is smaller than (pKey, nKey), or
** a positive value if pCur points at an etry that is larger than
** (pKey, nKey)).
**
** If the seekResult parameter is non-zero, then the caller guarantees that
** cursor pCur is pointing at the existing copy of a row that is to be
** overwritten. If the seekResult parameter is 0, then cursor pCur may
** point to any entry or to no entry at all and so this function has to seek
** the cursor before the new key can be inserted.
*/
static int sqlite3BtreeInsert(
BtCursor pCur, /* Insert data into the table of this cursor */
byte[] pKey, i64 nKey, /* The key of the new record */
byte[] pData, int nData, /* The data of the new record */
int nZero, /* Number of extra 0 bytes to append to data */
int appendBias, /* True if this is likely an append */
int seekResult /* Result of prior MovetoUnpacked() call */
)
{
int rc;
int loc = seekResult; /* -1: before desired location +1: after */
int szNew = 0;
int idx;
MemPage pPage;
Btree p = pCur.pBtree;
BtShared pBt = p.pBt;
int oldCell;
byte[] newCell = null;
if ( pCur.eState == CURSOR_FAULT )
{
Debug.Assert( pCur.skipNext != SQLITE_OK );
return pCur.skipNext;
}
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pCur.wrFlag != 0 && pBt.inTransaction == TRANS_WRITE && !pBt.readOnly );
Debug.Assert( hasSharedCacheTableLock( p, pCur.pgnoRoot, pCur.pKeyInfo != null ? 1 : 0, 2 ) );
/* Assert that the caller has been consistent. If this cursor was opened
** expecting an index b-tree, then the caller should be inserting blob
** keys with no associated data. If the cursor was opened expecting an
** intkey table, the caller should be inserting integer keys with a
** blob of associated data. */
Debug.Assert( ( pKey == null ) == ( pCur.pKeyInfo == null ) );
/* If this is an insert into a table b-tree, invalidate any incrblob
** cursors open on the row being replaced (assuming this is a replace
** operation - if it is not, the following is a no-op). */
if ( pCur.pKeyInfo == null )
{
invalidateIncrblobCursors( p, nKey, 0 );
}
/* Save the positions of any other cursors open on this table.
**
** In some cases, the call to btreeMoveto() below is a no-op. For
** example, when inserting data into a table with auto-generated integer
** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the
** integer key to use. It then calls this function to actually insert the
** data into the intkey B-Tree. In this case btreeMoveto() recognizes
** that the cursor is already where it needs to be and returns without
** doing any work. To avoid thwarting these optimizations, it is important
** not to clear the cursor here.
*/
rc = saveAllCursors( pBt, pCur.pgnoRoot, pCur );
if ( rc != 0 )
return rc;
if ( 0 == loc )
{
rc = btreeMoveto( pCur, pKey, nKey, appendBias, ref loc );
if ( rc != 0 )
return rc;
}
Debug.Assert( pCur.eState == CURSOR_VALID || ( pCur.eState == CURSOR_INVALID && loc != 0 ) );
pPage = pCur.apPage[pCur.iPage];
Debug.Assert( pPage.intKey != 0 || nKey >= 0 );
Debug.Assert( pPage.leaf != 0 || 0 == pPage.intKey );
TRACE( "INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
pCur.pgnoRoot, nKey, nData, pPage.pgno,
loc == 0 ? "overwrite" : "new entry" );
Debug.Assert( pPage.isInit != 0 );
allocateTempSpace( pBt );
newCell = pBt.pTmpSpace;
//if (newCell == null) return SQLITE_NOMEM;
rc = fillInCell( pPage, newCell, pKey, nKey, pData, nData, nZero, ref szNew );
if ( rc != 0 )
goto end_insert;
Debug.Assert( szNew == cellSizePtr( pPage, newCell ) );
Debug.Assert( szNew <= MX_CELL_SIZE( pBt ) );
idx = pCur.aiIdx[pCur.iPage];
if ( loc == 0 )
{
u16 szOld;
Debug.Assert( idx < pPage.nCell );
rc = sqlite3PagerWrite( pPage.pDbPage );
if ( rc != 0 )
{
goto end_insert;
}
oldCell = findCell( pPage, idx );
if ( 0 == pPage.leaf )
{
//memcpy(newCell, oldCell, 4);
newCell[0] = pPage.aData[oldCell + 0];
newCell[1] = pPage.aData[oldCell + 1];
newCell[2] = pPage.aData[oldCell + 2];
newCell[3] = pPage.aData[oldCell + 3];
}
szOld = cellSizePtr( pPage, oldCell );
rc = clearCell( pPage, oldCell );
dropCell( pPage, idx, szOld, ref rc );
if ( rc != 0 )
goto end_insert;
}
else if ( loc < 0 && pPage.nCell > 0 )
{
Debug.Assert( pPage.leaf != 0 );
idx = ++pCur.aiIdx[pCur.iPage];
}
else
{
Debug.Assert( pPage.leaf != 0 );
}
insertCell( pPage, idx, newCell, szNew, null, 0, ref rc );
Debug.Assert( rc != SQLITE_OK || pPage.nCell > 0 || pPage.nOverflow > 0 );
/* If no error has occured and pPage has an overflow cell, call balance()
** to redistribute the cells within the tree. Since balance() may move
** the cursor, zero the BtCursor.info.nSize and BtCursor.validNKey
** variables.
**
** Previous versions of SQLite called moveToRoot() to move the cursor
** back to the root page as balance() used to invalidate the contents
** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,
** set the cursor state to "invalid". This makes common insert operations
** slightly faster.
**
** There is a subtle but important optimization here too. When inserting
** multiple records into an intkey b-tree using a single cursor (as can
** happen while processing an "INSERT INTO ... SELECT" statement), it
** is advantageous to leave the cursor pointing to the last entry in
** the b-tree if possible. If the cursor is left pointing to the last
** entry in the table, and the next row inserted has an integer key
** larger than the largest existing key, it is possible to insert the
** row without seeking the cursor. This can be a big performance boost.
*/
pCur.info.nSize = 0;
pCur.validNKey = false;
if ( rc == SQLITE_OK && pPage.nOverflow != 0 )
{
rc = balance( pCur );
/* Must make sure nOverflow is reset to zero even if the balance()
** fails. Internal data structure corruption will result otherwise.
** Also, set the cursor state to invalid. This stops saveCursorPosition()
** from trying to save the current position of the cursor. */
pCur.apPage[pCur.iPage].nOverflow = 0;
pCur.eState = CURSOR_INVALID;
}
Debug.Assert( pCur.apPage[pCur.iPage].nOverflow == 0 );
end_insert:
return rc;
}
/*
** Delete the entry that the cursor is pointing to. The cursor
** is left pointing at a arbitrary location.
*/
static int sqlite3BtreeDelete( BtCursor pCur )
{
Btree p = pCur.pBtree;
BtShared pBt = p.pBt;
int rc; /* Return code */
MemPage pPage; /* Page to delete cell from */
int pCell; /* Pointer to cell to delete */
int iCellIdx; /* Index of cell to delete */
int iCellDepth; /* Depth of node containing pCell */
Debug.Assert( cursorHoldsMutex( pCur ) );
Debug.Assert( pBt.inTransaction == TRANS_WRITE );
Debug.Assert( !pBt.readOnly );
Debug.Assert( pCur.wrFlag != 0 );
Debug.Assert( hasSharedCacheTableLock( p, pCur.pgnoRoot, pCur.pKeyInfo != null ? 1 : 0, 2 ) );
Debug.Assert( !hasReadConflicts( p, pCur.pgnoRoot ) );
if ( NEVER( pCur.aiIdx[pCur.iPage] >= pCur.apPage[pCur.iPage].nCell )
|| NEVER( pCur.eState != CURSOR_VALID )
)
{
return SQLITE_ERROR; /* Something has gone awry. */
}
/* If this is a delete operation to remove a row from a table b-tree,
** invalidate any incrblob cursors open on the row being deleted. */
if ( pCur.pKeyInfo == null )
{
invalidateIncrblobCursors( p, pCur.info.nKey, 0 );
}
iCellDepth = pCur.iPage;
iCellIdx = pCur.aiIdx[iCellDepth];
pPage = pCur.apPage[iCellDepth];
pCell = findCell( pPage, iCellIdx );
/* If the page containing the entry to delete is not a leaf page, move
** the cursor to the largest entry in the tree that is smaller than
** the entry being deleted. This cell will replace the cell being deleted
** from the internal node. The 'previous' entry is used for this instead
** of the 'next' entry, as the previous entry is always a part of the
** sub-tree headed by the child page of the cell being deleted. This makes
** balancing the tree following the delete operation easier. */
if ( 0 == pPage.leaf )
{
int notUsed = 0;
rc = sqlite3BtreePrevious( pCur, ref notUsed );
if ( rc != 0 )
return rc;
}
/* Save the positions of any other cursors open on this table before
** making any modifications. Make the page containing the entry to be
** deleted writable. Then free any overflow pages associated with the
** entry and finally remove the cell itself from within the page.
*/
rc = saveAllCursors( pBt, pCur.pgnoRoot, pCur );
if ( rc != 0 )
return rc;
rc = sqlite3PagerWrite( pPage.pDbPage );
if ( rc != 0 )
return rc;
rc = clearCell( pPage, pCell );
dropCell( pPage, iCellIdx, cellSizePtr( pPage, pCell ), ref rc );
if ( rc != 0 )
return rc;
/* If the cell deleted was not located on a leaf page, then the cursor
** is currently pointing to the largest entry in the sub-tree headed
** by the child-page of the cell that was just deleted from an internal
** node. The cell from the leaf node needs to be moved to the internal
** node to replace the deleted cell. */
if ( 0 == pPage.leaf )
{
MemPage pLeaf = pCur.apPage[pCur.iPage];
int nCell;
Pgno n = pCur.apPage[iCellDepth + 1].pgno;
//byte[] pTmp;
pCell = findCell( pLeaf, pLeaf.nCell - 1 );
nCell = cellSizePtr( pLeaf, pCell );
Debug.Assert( MX_CELL_SIZE( pBt ) >= nCell );
//allocateTempSpace(pBt);
//pTmp = pBt.pTmpSpace;
rc = sqlite3PagerWrite( pLeaf.pDbPage );
byte[] pNext_4 = sqlite3Malloc( nCell + 4 );
Buffer.BlockCopy( pLeaf.aData, pCell - 4, pNext_4, 0, nCell + 4 );
insertCell( pPage, iCellIdx, pNext_4, nCell + 4, null, n, ref rc ); //insertCell( pPage, iCellIdx, pCell - 4, nCell + 4, pTmp, n, ref rc );
dropCell( pLeaf, pLeaf.nCell - 1, nCell, ref rc );
if ( rc != 0 )
return rc;
}
/* Balance the tree. If the entry deleted was located on a leaf page,
** then the cursor still points to that page. In this case the first
** call to balance() repairs the tree, and the if(...) condition is
** never true.
**
** Otherwise, if the entry deleted was on an internal node page, then
** pCur is pointing to the leaf page from which a cell was removed to
** replace the cell deleted from the internal node. This is slightly
** tricky as the leaf node may be underfull, and the internal node may
** be either under or overfull. In this case run the balancing algorithm
** on the leaf node first. If the balance proceeds far enough up the
** tree that we can be sure that any problem in the internal node has
** been corrected, so be it. Otherwise, after balancing the leaf node,
** walk the cursor up the tree to the internal node and balance it as
** well. */
rc = balance( pCur );
if ( rc == SQLITE_OK && pCur.iPage > iCellDepth )
{
while ( pCur.iPage > iCellDepth )
{
releasePage( pCur.apPage[pCur.iPage--] );
}
rc = balance( pCur );
}
if ( rc == SQLITE_OK )
{
moveToRoot( pCur );
}
return rc;
}
/*
** Create a new BTree table. Write into piTable the page
** number for the root page of the new table.
**
** The type of type is determined by the flags parameter. Only the
** following values of flags are currently in use. Other values for
** flags might not work:
**
** BTREE_INTKEY|BTREE_LEAFDATA Used for SQL tables with rowid keys
** BTREE_ZERODATA Used for SQL indices
*/
static int btreeCreateTable( Btree p, ref int piTable, int createTabFlags )
{
BtShared pBt = p.pBt;
MemPage pRoot = new MemPage();
Pgno pgnoRoot = 0;
int rc;
int ptfFlags; /* Page-type flage for the root page of new table */
Debug.Assert( sqlite3BtreeHoldsMutex( p ) );
Debug.Assert( pBt.inTransaction == TRANS_WRITE );
Debug.Assert( !pBt.readOnly );
#if SQLITE_OMIT_AUTOVACUUM
rc = allocateBtreePage(pBt, ref pRoot, ref pgnoRoot, 1, 0);
if( rc !=0){
return rc;
}
#else
if ( pBt.autoVacuum )
{
Pgno pgnoMove = 0; /* Move a page here to make room for the root-page */
MemPage pPageMove = new MemPage(); /* The page to move to. */
/* Creating a new table may probably require moving an existing database
** to make room for the new tables root page. In case this page turns
** out to be an overflow page, delete all overflow page-map caches
** held by open cursors.
*/
invalidateAllOverflowCache( pBt );
/* Read the value of meta[3] from the database to determine where the
** root page of the new table should go. meta[3] is the largest root-page
** created so far, so the new root-page is (meta[3]+1).
*/
sqlite3BtreeGetMeta( p, BTREE_LARGEST_ROOT_PAGE, ref pgnoRoot );
pgnoRoot++;
/* The new root-page may not be allocated on a pointer-map page, or the
** PENDING_BYTE page.
*/
while ( pgnoRoot == PTRMAP_PAGENO( pBt, pgnoRoot ) ||
pgnoRoot == PENDING_BYTE_PAGE( pBt ) )
{
pgnoRoot++;
}
Debug.Assert( pgnoRoot >= 3 );
/* Allocate a page. The page that currently resides at pgnoRoot will
** be moved to the allocated page (unless the allocated page happens
** to reside at pgnoRoot).
*/
rc = allocateBtreePage( pBt, ref pPageMove, ref pgnoMove, pgnoRoot, 1 );
if ( rc != SQLITE_OK )
{
return rc;
}
if ( pgnoMove != pgnoRoot )
{
/* pgnoRoot is the page that will be used for the root-page of
** the new table (assuming an error did not occur). But we were
** allocated pgnoMove. If required (i.e. if it was not allocated
** by extending the file), the current page at position pgnoMove
** is already journaled.
*/
u8 eType = 0;
Pgno iPtrPage = 0;
releasePage( pPageMove );
/* Move the page currently at pgnoRoot to pgnoMove. */
rc = btreeGetPage( pBt, pgnoRoot, ref pRoot, 0 );
if ( rc != SQLITE_OK )
{
return rc;
}
rc = ptrmapGet( pBt, pgnoRoot, ref eType, ref iPtrPage );
if ( eType == PTRMAP_ROOTPAGE || eType == PTRMAP_FREEPAGE )
{
rc = SQLITE_CORRUPT_BKPT();
}
if ( rc != SQLITE_OK )
{
releasePage( pRoot );
return rc;
}
Debug.Assert( eType != PTRMAP_ROOTPAGE );
Debug.Assert( eType != PTRMAP_FREEPAGE );
rc = relocatePage( pBt, pRoot, eType, iPtrPage, pgnoMove, 0 );
releasePage( pRoot );
/* Obtain the page at pgnoRoot */
if ( rc != SQLITE_OK )
{
return rc;
}
rc = btreeGetPage( pBt, pgnoRoot, ref pRoot, 0 );
if ( rc != SQLITE_OK )
{
return rc;
}
rc = sqlite3PagerWrite( pRoot.pDbPage );
if ( rc != SQLITE_OK )
{
releasePage( pRoot );
return rc;
}
}
else
{
pRoot = pPageMove;
}
/* Update the pointer-map and meta-data with the new root-page number. */
ptrmapPut( pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0, ref rc );
if ( rc != 0 )
{
releasePage( pRoot );
return rc;
}
/* When the new root page was allocated, page 1 was made writable in
** order either to increase the database filesize, or to decrement the
** freelist count. Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
*/
Debug.Assert( sqlite3PagerIswriteable( pBt.pPage1.pDbPage ) );
rc = sqlite3BtreeUpdateMeta( p, 4, pgnoRoot );
if ( NEVER( rc != 0 ) )
{
releasePage( pRoot );
return rc;
}
}
else
{
rc = allocateBtreePage( pBt, ref pRoot, ref pgnoRoot, 1, 0 );
if ( rc != 0 )
return rc;
}
#endif
Debug.Assert( sqlite3PagerIswriteable( pRoot.pDbPage ) );
if ( ( createTabFlags & BTREE_INTKEY ) != 0 )
{
ptfFlags = PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF;
}
else
{
ptfFlags = PTF_ZERODATA | PTF_LEAF;
}
zeroPage( pRoot, ptfFlags );
sqlite3PagerUnref( pRoot.pDbPage );
Debug.Assert( ( pBt.openFlags & BTREE_SINGLE ) == 0 || pgnoRoot == 2 );
piTable = (int)pgnoRoot;
return SQLITE_OK;
}
static int sqlite3BtreeCreateTable( Btree p, ref int piTable, int flags )
{
int rc;
sqlite3BtreeEnter( p );
rc = btreeCreateTable( p, ref piTable, flags );
sqlite3BtreeLeave( p );
return rc;
}
/*
** Erase the given database page and all its children. Return
** the page to the freelist.
*/
static int clearDatabasePage(
BtShared pBt, /* The BTree that contains the table */
Pgno pgno, /* Page number to clear */
int freePageFlag, /* Deallocate page if true */
ref int pnChange /* Add number of Cells freed to this counter */
)
{
MemPage pPage = new MemPage();
int rc;
byte[] pCell;
int i;
Debug.Assert( sqlite3_mutex_held( pBt.mutex ) );
if ( pgno > btreePagecount( pBt ) )
{
return SQLITE_CORRUPT_BKPT();
}
rc = getAndInitPage( pBt, pgno, ref pPage );
if ( rc != 0 )
return rc;
for ( i = 0; i < pPage.nCell; i++ )
{
int iCell = findCell( pPage, i );
pCell = pPage.aData; // pCell = findCell( pPage, i );
if ( 0 == pPage.leaf )
{
rc = clearDatabasePage( pBt, sqlite3Get4byte( pCell, iCell ), 1, ref pnChange );
if ( rc != 0 )
goto cleardatabasepage_out;
}
rc = clearCell( pPage, iCell );
if ( rc != 0 )
goto cleardatabasepage_out;
}
if ( 0 == pPage.leaf )
{
rc = clearDatabasePage( pBt, sqlite3Get4byte( pPage.aData, 8 ), 1, ref pnChange );
if ( rc != 0 )
goto cleardatabasepage_out;
}
else //if (pnChange != 0)
{
//Debug.Assert(pPage.intKey != 0);
pnChange += pPage.nCell;
}
if ( freePageFlag != 0 )
{
freePage( pPage, ref rc );
}
else if ( ( rc = sqlite3PagerWrite( pPage.pDbPage ) ) == 0 )
{
zeroPage( pPage, pPage.aData[0] | PTF_LEAF );
}
cleardatabasepage_out:
releasePage( pPage );
return rc;
}
/*
** Delete all information from a single table in the database. iTable is
** the page number of the root of the table. After this routine returns,
** the root page is empty, but still exists.
**
** This routine will fail with SQLITE_LOCKED if there are any open
** read cursors on the table. Open write cursors are moved to the
** root of the table.
**
** If pnChange is not NULL, then table iTable must be an intkey table. The
** integer value pointed to by pnChange is incremented by the number of
** entries in the table.
*/
static int sqlite3BtreeClearTable( Btree p, int iTable, ref int pnChange )
{
int rc;
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
Debug.Assert( p.inTrans == TRANS_WRITE );
/* Invalidate all incrblob cursors open on table iTable (assuming iTable
** is the root of a table b-tree - if it is not, the following call is
** a no-op). */
invalidateIncrblobCursors( p, 0, 1 );
rc = saveAllCursors( pBt, (Pgno)iTable, null );
if ( SQLITE_OK == rc )
{
rc = clearDatabasePage( pBt, (Pgno)iTable, 0, ref pnChange );
}
sqlite3BtreeLeave( p );
return rc;
}
/*
** Erase all information in a table and add the root of the table to
** the freelist. Except, the root of the principle table (the one on
** page 1) is never added to the freelist.
**
** This routine will fail with SQLITE_LOCKED if there are any open
** cursors on the table.
**
** If AUTOVACUUM is enabled and the page at iTable is not the last
** root page in the database file, then the last root page
** in the database file is moved into the slot formerly occupied by
** iTable and that last slot formerly occupied by the last root page
** is added to the freelist instead of iTable. In this say, all
** root pages are kept at the beginning of the database file, which
** is necessary for AUTOVACUUM to work right. piMoved is set to the
** page number that used to be the last root page in the file before
** the move. If no page gets moved, piMoved is set to 0.
** The last root page is recorded in meta[3] and the value of
** meta[3] is updated by this procedure.
*/
static int btreeDropTable( Btree p, Pgno iTable, ref int piMoved )
{
int rc;
MemPage pPage = null;
BtShared pBt = p.pBt;
Debug.Assert( sqlite3BtreeHoldsMutex( p ) );
Debug.Assert( p.inTrans == TRANS_WRITE );
/* It is illegal to drop a table if any cursors are open on the
** database. This is because in auto-vacuum mode the backend may
** need to move another root-page to fill a gap left by the deleted
** root page. If an open cursor was using this page a problem would
** occur.
**
** This error is caught long before control reaches this point.
*/
if ( NEVER( pBt.pCursor ) )
{
sqlite3ConnectionBlocked( p.db, pBt.pCursor.pBtree.db );
return SQLITE_LOCKED_SHAREDCACHE;
}
rc = btreeGetPage( pBt, (Pgno)iTable, ref pPage, 0 );
if ( rc != 0 )
return rc;
int Dummy0 = 0;
rc = sqlite3BtreeClearTable( p, (int)iTable, ref Dummy0 );
if ( rc != 0 )
{
releasePage( pPage );
return rc;
}
piMoved = 0;
if ( iTable > 1 )
{
#if SQLITE_OMIT_AUTOVACUUM
freePage(pPage, ref rc);
releasePage(pPage);
#else
if ( pBt.autoVacuum )
{
Pgno maxRootPgno = 0;
sqlite3BtreeGetMeta( p, BTREE_LARGEST_ROOT_PAGE, ref maxRootPgno );
if ( iTable == maxRootPgno )
{
/* If the table being dropped is the table with the largest root-page
** number in the database, put the root page on the free list.
*/
freePage( pPage, ref rc );
releasePage( pPage );
if ( rc != SQLITE_OK )
{
return rc;
}
}
else
{
/* The table being dropped does not have the largest root-page
** number in the database. So move the page that does into the
** gap left by the deleted root-page.
*/
MemPage pMove = new MemPage();
releasePage( pPage );
rc = btreeGetPage( pBt, maxRootPgno, ref pMove, 0 );
if ( rc != SQLITE_OK )
{
return rc;
}
rc = relocatePage( pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable, 0 );
releasePage( pMove );
if ( rc != SQLITE_OK )
{
return rc;
}
pMove = null;
rc = btreeGetPage( pBt, maxRootPgno, ref pMove, 0 );
freePage( pMove, ref rc );
releasePage( pMove );
if ( rc != SQLITE_OK )
{
return rc;
}
piMoved = (int)maxRootPgno;
}
/* Set the new 'max-root-page' value in the database header. This
** is the old value less one, less one more if that happens to
** be a root-page number, less one again if that is the
** PENDING_BYTE_PAGE.
*/
maxRootPgno--;
while ( maxRootPgno == PENDING_BYTE_PAGE( pBt )
|| PTRMAP_ISPAGE( pBt, maxRootPgno ) )
{
maxRootPgno--;
}
Debug.Assert( maxRootPgno != PENDING_BYTE_PAGE( pBt ) );
rc = sqlite3BtreeUpdateMeta( p, 4, maxRootPgno );
}
else
{
freePage( pPage, ref rc );
releasePage( pPage );
}
#endif
}
else
{
/* If sqlite3BtreeDropTable was called on page 1.
** This really never should happen except in a corrupt
** database.
*/
zeroPage( pPage, PTF_INTKEY | PTF_LEAF );
releasePage( pPage );
}
return rc;
}
static int sqlite3BtreeDropTable( Btree p, int iTable, ref int piMoved )
{
int rc;
sqlite3BtreeEnter( p );
rc = btreeDropTable( p, (u32)iTable, ref piMoved );
sqlite3BtreeLeave( p );
return rc;
}
/*
** This function may only be called if the b-tree connection already
** has a read or write transaction open on the database.
**
** Read the meta-information out of a database file. Meta[0]
** is the number of free pages currently in the database. Meta[1]
** through meta[15] are available for use by higher layers. Meta[0]
** is read-only, the others are read/write.
**
** The schema layer numbers meta values differently. At the schema
** layer (and the SetCookie and ReadCookie opcodes) the number of
** free pages is not visible. So Cookie[0] is the same as Meta[1].
*/
static void sqlite3BtreeGetMeta( Btree p, int idx, ref u32 pMeta )
{
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
Debug.Assert( p.inTrans > TRANS_NONE );
Debug.Assert( SQLITE_OK == querySharedCacheTableLock( p, MASTER_ROOT, READ_LOCK ) );
Debug.Assert( pBt.pPage1 != null );
Debug.Assert( idx >= 0 && idx <= 15 );
pMeta = sqlite3Get4byte( pBt.pPage1.aData, 36 + idx * 4 );
/* If auto-vacuum is disabled in this build and this is an auto-vacuum
** database, mark the database as read-only. */
#if SQLITE_OMIT_AUTOVACUUM
if( idx==BTREE_LARGEST_ROOT_PAGE && pMeta>0 ) pBt.readOnly = 1;
#endif
sqlite3BtreeLeave( p );
}
/*
** Write meta-information back into the database. Meta[0] is
** read-only and may not be written.
*/
static int sqlite3BtreeUpdateMeta( Btree p, int idx, u32 iMeta )
{
BtShared pBt = p.pBt;
byte[] pP1;
int rc;
Debug.Assert( idx >= 1 && idx <= 15 );
sqlite3BtreeEnter( p );
Debug.Assert( p.inTrans == TRANS_WRITE );
Debug.Assert( pBt.pPage1 != null );
pP1 = pBt.pPage1.aData;
rc = sqlite3PagerWrite( pBt.pPage1.pDbPage );
if ( rc == SQLITE_OK )
{
sqlite3Put4byte( pP1, 36 + idx * 4, iMeta );
#if !SQLITE_OMIT_AUTOVACUUM
if ( idx == BTREE_INCR_VACUUM )
{
Debug.Assert( pBt.autoVacuum || iMeta == 0 );
Debug.Assert( iMeta == 0 || iMeta == 1 );
pBt.incrVacuum = iMeta != 0;
}
#endif
}
sqlite3BtreeLeave( p );
return rc;
}
#if !SQLITE_OMIT_BTREECOUNT
/*
** The first argument, pCur, is a cursor opened on some b-tree. Count the
** number of entries in the b-tree and write the result to pnEntry.
**
** SQLITE_OK is returned if the operation is successfully executed.
** Otherwise, if an error is encountered (i.e. an IO error or database
** corruption) an SQLite error code is returned.
*/
static int sqlite3BtreeCount( BtCursor pCur, ref i64 pnEntry )
{
i64 nEntry = 0; /* Value to return in pnEntry */
int rc; /* Return code */
rc = moveToRoot( pCur );
/* Unless an error occurs, the following loop runs one iteration for each
** page in the B-Tree structure (not including overflow pages).
*/
while ( rc == SQLITE_OK )
{
int iIdx; /* Index of child node in parent */
MemPage pPage; /* Current page of the b-tree */
/* If this is a leaf page or the tree is not an int-key tree, then
** this page contains countable entries. Increment the entry counter
** accordingly.
*/
pPage = pCur.apPage[pCur.iPage];
if ( pPage.leaf != 0 || 0 == pPage.intKey )
{
nEntry += pPage.nCell;
}
/* pPage is a leaf node. This loop navigates the cursor so that it
** points to the first interior cell that it points to the parent of
** the next page in the tree that has not yet been visited. The
** pCur.aiIdx[pCur.iPage] value is set to the index of the parent cell
** of the page, or to the number of cells in the page if the next page
** to visit is the right-child of its parent.
**
** If all pages in the tree have been visited, return SQLITE_OK to the
** caller.
*/
if ( pPage.leaf != 0 )
{
do
{
if ( pCur.iPage == 0 )
{
/* All pages of the b-tree have been visited. Return successfully. */
pnEntry = nEntry;
return SQLITE_OK;
}
moveToParent( pCur );
} while ( pCur.aiIdx[pCur.iPage] >= pCur.apPage[pCur.iPage].nCell );
pCur.aiIdx[pCur.iPage]++;
pPage = pCur.apPage[pCur.iPage];
}
/* Descend to the child node of the cell that the cursor currently
** points at. This is the right-child if (iIdx==pPage.nCell).
*/
iIdx = pCur.aiIdx[pCur.iPage];
if ( iIdx == pPage.nCell )
{
rc = moveToChild( pCur, sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 ) );
}
else
{
rc = moveToChild( pCur, sqlite3Get4byte( pPage.aData, findCell( pPage, iIdx ) ) );
}
}
/* An error has occurred. Return an error code. */
return rc;
}
#endif
/*
** Return the pager associated with a BTree. This routine is used for
** testing and debugging only.
*/
static Pager sqlite3BtreePager( Btree p )
{
return p.pBt.pPager;
}
#if !SQLITE_OMIT_INTEGRITY_CHECK
/*
** Append a message to the error message string.
*/
static void checkAppendMsg(
IntegrityCk pCheck,
string zMsg1,
string zFormat,
params object[] ap
)
{
if ( 0 == pCheck.mxErr )
return;
//va_list ap;
lock ( lock_va_list )
{
pCheck.mxErr--;
pCheck.nErr++;
va_start( ap, zFormat );
if ( pCheck.errMsg.zText.Length != 0 )
{
sqlite3StrAccumAppend( pCheck.errMsg, "\n", 1 );
}
if ( zMsg1.Length > 0 )
{
sqlite3StrAccumAppend( pCheck.errMsg, zMsg1.ToString(), -1 );
}
sqlite3VXPrintf( pCheck.errMsg, 1, zFormat, ap );
va_end( ref ap );
}
}
static void checkAppendMsg(
IntegrityCk pCheck,
StringBuilder zMsg1,
string zFormat,
params object[] ap
)
{
if ( 0 == pCheck.mxErr )
return;
//va_list ap;
lock ( lock_va_list )
{
pCheck.mxErr--;
pCheck.nErr++;
va_start( ap, zFormat );
if ( pCheck.errMsg.zText.Length != 0 )
{
sqlite3StrAccumAppend( pCheck.errMsg, "\n", 1 );
}
if ( zMsg1.Length > 0 )
{
sqlite3StrAccumAppend( pCheck.errMsg, zMsg1.ToString(), -1 );
}
sqlite3VXPrintf( pCheck.errMsg, 1, zFormat, ap );
va_end( ref ap );
}
//if( pCheck.errMsg.mallocFailed ){
// pCheck.mallocFailed = 1;
//}
}
#endif //* SQLITE_OMIT_INTEGRITY_CHECK */
#if !SQLITE_OMIT_INTEGRITY_CHECK
/*
** Add 1 to the reference count for page iPage. If this is the second
** reference to the page, add an error message to pCheck.zErrMsg.
** Return 1 if there are 2 ore more references to the page and 0 if
** if this is the first reference to the page.
**
** Also check that the page number is in bounds.
*/
static int checkRef( IntegrityCk pCheck, Pgno iPage, string zContext )
{
if ( iPage == 0 )
return 1;
if ( iPage > pCheck.nPage )
{
checkAppendMsg( pCheck, zContext, "invalid page number %d", iPage );
return 1;
}
if ( pCheck.anRef[iPage] == 1 )
{
checkAppendMsg( pCheck, zContext, "2nd reference to page %d", iPage );
return 1;
}
return ( ( pCheck.anRef[iPage]++ ) > 1 ) ? 1 : 0;
}
#if !SQLITE_OMIT_AUTOVACUUM
/*
** Check that the entry in the pointer-map for page iChild maps to
** page iParent, pointer type ptrType. If not, append an error message
** to pCheck.
*/
static void checkPtrmap(
IntegrityCk pCheck, /* Integrity check context */
Pgno iChild, /* Child page number */
u8 eType, /* Expected pointer map type */
Pgno iParent, /* Expected pointer map parent page number */
string zContext /* Context description (used for error msg) */
)
{
int rc;
u8 ePtrmapType = 0;
Pgno iPtrmapParent = 0;
rc = ptrmapGet( pCheck.pBt, iChild, ref ePtrmapType, ref iPtrmapParent );
if ( rc != SQLITE_OK )
{
//if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) pCheck.mallocFailed = 1;
checkAppendMsg( pCheck, zContext, "Failed to read ptrmap key=%d", iChild );
return;
}
if ( ePtrmapType != eType || iPtrmapParent != iParent )
{
checkAppendMsg( pCheck, zContext,
"Bad ptr map entry key=%d expected=(%d,%d) got=(%d,%d)",
iChild, eType, iParent, ePtrmapType, iPtrmapParent );
}
}
#endif
/*
** Check the integrity of the freelist or of an overflow page list.
** Verify that the number of pages on the list is N.
*/
static void checkList(
IntegrityCk pCheck, /* Integrity checking context */
int isFreeList, /* True for a freelist. False for overflow page list */
int iPage, /* Page number for first page in the list */
int N, /* Expected number of pages in the list */
string zContext /* Context for error messages */
)
{
int i;
int expected = N;
int iFirst = iPage;
while ( N-- > 0 && pCheck.mxErr != 0 )
{
PgHdr pOvflPage = new PgHdr();
byte[] pOvflData;
if ( iPage < 1 )
{
checkAppendMsg( pCheck, zContext,
"%d of %d pages missing from overflow list starting at %d",
N + 1, expected, iFirst );
break;
}
if ( checkRef( pCheck, (u32)iPage, zContext ) != 0 )
break;
if ( sqlite3PagerGet( pCheck.pPager, (Pgno)iPage, ref pOvflPage ) != 0 )
{
checkAppendMsg( pCheck, zContext, "failed to get page %d", iPage );
break;
}
pOvflData = sqlite3PagerGetData( pOvflPage );
if ( isFreeList != 0 )
{
int n = (int)sqlite3Get4byte( pOvflData, 4 );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pCheck.pBt.autoVacuum )
{
checkPtrmap( pCheck, (u32)iPage, PTRMAP_FREEPAGE, 0, zContext );
}
#endif
if ( n > (int)pCheck.pBt.usableSize / 4 - 2 )
{
checkAppendMsg( pCheck, zContext,
"freelist leaf count too big on page %d", iPage );
N--;
}
else
{
for ( i = 0; i < n; i++ )
{
Pgno iFreePage = sqlite3Get4byte( pOvflData, 8 + i * 4 );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pCheck.pBt.autoVacuum )
{
checkPtrmap( pCheck, iFreePage, PTRMAP_FREEPAGE, 0, zContext );
}
#endif
checkRef( pCheck, iFreePage, zContext );
}
N -= n;
}
}
#if !SQLITE_OMIT_AUTOVACUUM
else
{
/* If this database supports auto-vacuum and iPage is not the last
** page in this overflow list, check that the pointer-map entry for
** the following page matches iPage.
*/
if ( pCheck.pBt.autoVacuum && N > 0 )
{
i = (int)sqlite3Get4byte( pOvflData );
checkPtrmap( pCheck, (u32)i, PTRMAP_OVERFLOW2, (u32)iPage, zContext );
}
}
#endif
iPage = (int)sqlite3Get4byte( pOvflData );
sqlite3PagerUnref( pOvflPage );
}
}
#endif //* SQLITE_OMIT_INTEGRITY_CHECK */
#if !SQLITE_OMIT_INTEGRITY_CHECK
/*
** Do various sanity checks on a single page of a tree. Return
** the tree depth. Root pages return 0. Parents of root pages
** return 1, and so forth.
**
** These checks are done:
**
** 1. Make sure that cells and freeblocks do not overlap
** but combine to completely cover the page.
** NO 2. Make sure cell keys are in order.
** NO 3. Make sure no key is less than or equal to zLowerBound.
** NO 4. Make sure no key is greater than or equal to zUpperBound.
** 5. Check the integrity of overflow pages.
** 6. Recursively call checkTreePage on all children.
** 7. Verify that the depth of all children is the same.
** 8. Make sure this page is at least 33% full or else it is
** the root of the tree.
*/
static i64 refNULL = 0; //Dummy for C# ref NULL
static int checkTreePage(
IntegrityCk pCheck, /* Context for the sanity check */
int iPage, /* Page number of the page to check */
string zParentContext, /* Parent context */
ref i64 pnParentMinKey,
ref i64 pnParentMaxKey,
object _pnParentMinKey, /* C# Needed to determine if content passed*/
object _pnParentMaxKey /* C# Needed to determine if content passed*/
)
{
MemPage pPage = new MemPage();
int i, rc, depth, d2, pgno, cnt;
int hdr, cellStart;
int nCell;
u8[] data;
BtShared pBt;
int usableSize;
StringBuilder zContext = new StringBuilder( 100 );
byte[] hit = null;
i64 nMinKey = 0;
i64 nMaxKey = 0;
sqlite3_snprintf( 200, zContext, "Page %d: ", iPage );
/* Check that the page exists
*/
pBt = pCheck.pBt;
usableSize = (int)pBt.usableSize;
if ( iPage == 0 )
return 0;
if ( checkRef( pCheck, (u32)iPage, zParentContext ) != 0 )
return 0;
if ( ( rc = btreeGetPage( pBt, (Pgno)iPage, ref pPage, 0 ) ) != 0 )
{
checkAppendMsg( pCheck, zContext.ToString(),
"unable to get the page. error code=%d", rc );
return 0;
}
/* Clear MemPage.isInit to make sure the corruption detection code in
** btreeInitPage() is executed. */
pPage.isInit = 0;
if ( ( rc = btreeInitPage( pPage ) ) != 0 )
{
Debug.Assert( rc == SQLITE_CORRUPT ); /* The only possible error from InitPage */
checkAppendMsg( pCheck, zContext.ToString(),
"btreeInitPage() returns error code %d", rc );
releasePage( pPage );
return 0;
}
/* Check out all the cells.
*/
depth = 0;
for ( i = 0; i < pPage.nCell && pCheck.mxErr != 0; i++ )
{
u8[] pCell;
u32 sz;
CellInfo info = new CellInfo();
/* Check payload overflow pages
*/
sqlite3_snprintf( 200, zContext,
"On tree page %d cell %d: ", iPage, i );
int iCell = findCell( pPage, i ); //pCell = findCell( pPage, i );
pCell = pPage.aData;
btreeParseCellPtr( pPage, iCell, ref info ); //btreeParseCellPtr( pPage, pCell, info );
sz = info.nData;
if ( 0 == pPage.intKey )
sz += (u32)info.nKey;
/* For intKey pages, check that the keys are in order.
*/
else if ( i == 0 )
nMinKey = nMaxKey = info.nKey;
else
{
if ( info.nKey <= nMaxKey )
{
checkAppendMsg( pCheck, zContext.ToString(),
"Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey );
}
nMaxKey = info.nKey;
}
Debug.Assert( sz == info.nPayload );
if ( ( sz > info.nLocal )
//&& (pCell[info.iOverflow]<=&pPage.aData[pBt.usableSize])
)
{
int nPage = (int)( sz - info.nLocal + usableSize - 5 ) / ( usableSize - 4 );
Pgno pgnoOvfl = sqlite3Get4byte( pCell, iCell, info.iOverflow );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pBt.autoVacuum )
{
checkPtrmap( pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, (u32)iPage, zContext.ToString() );
}
#endif
checkList( pCheck, 0, (int)pgnoOvfl, nPage, zContext.ToString() );
}
/* Check sanity of left child page.
*/
if ( 0 == pPage.leaf )
{
pgno = (int)sqlite3Get4byte( pCell, iCell ); //sqlite3Get4byte( pCell );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pBt.autoVacuum )
{
checkPtrmap( pCheck, (u32)pgno, PTRMAP_BTREE, (u32)iPage, zContext.ToString() );
}
#endif
if ( i == 0 )
d2 = checkTreePage( pCheck, pgno, zContext.ToString(), ref nMinKey, ref refNULL, pCheck, null );
else
d2 = checkTreePage( pCheck, pgno, zContext.ToString(), ref nMinKey, ref nMaxKey, pCheck, pCheck );
if ( i > 0 && d2 != depth )
{
checkAppendMsg( pCheck, zContext, "Child page depth differs" );
}
depth = d2;
}
}
if ( 0 == pPage.leaf )
{
pgno = (int)sqlite3Get4byte( pPage.aData, pPage.hdrOffset + 8 );
sqlite3_snprintf( 200, zContext,
"On page %d at right child: ", iPage );
#if !SQLITE_OMIT_AUTOVACUUM
if ( pBt.autoVacuum )
{
checkPtrmap( pCheck, (u32)pgno, PTRMAP_BTREE, (u32)iPage, zContext.ToString() );
}
#endif
// checkTreePage(pCheck, pgno, zContext, NULL, !pPage->nCell ? NULL : &nMaxKey);
if ( 0 == pPage.nCell )
checkTreePage( pCheck, pgno, zContext.ToString(), ref refNULL, ref refNULL, null, null );
else
checkTreePage( pCheck, pgno, zContext.ToString(), ref refNULL, ref nMaxKey, null, pCheck );
}
/* For intKey leaf pages, check that the min/max keys are in order
** with any left/parent/right pages.
*/
if ( pPage.leaf != 0 && pPage.intKey != 0 )
{
/* if we are a left child page */
if ( _pnParentMinKey != null )
{
/* if we are the left most child page */
if ( _pnParentMaxKey == null )
{
if ( nMaxKey > pnParentMinKey )
{
checkAppendMsg( pCheck, zContext,
"Rowid %lld out of order (max larger than parent min of %lld)",
nMaxKey, pnParentMinKey );
}
}
else
{
if ( nMinKey <= pnParentMinKey )
{
checkAppendMsg( pCheck, zContext,
"Rowid %lld out of order (min less than parent min of %lld)",
nMinKey, pnParentMinKey );
}
if ( nMaxKey > pnParentMaxKey )
{
checkAppendMsg( pCheck, zContext,
"Rowid %lld out of order (max larger than parent max of %lld)",
nMaxKey, pnParentMaxKey );
}
pnParentMinKey = nMaxKey;
}
/* else if we're a right child page */
}
else if ( _pnParentMaxKey != null )
{
if ( nMinKey <= pnParentMaxKey )
{
checkAppendMsg( pCheck, zContext,
"Rowid %lld out of order (min less than parent max of %lld)",
nMinKey, pnParentMaxKey );
}
}
}
/* Check for complete coverage of the page
*/
data = pPage.aData;
hdr = pPage.hdrOffset;
hit = sqlite3Malloc( pBt.pageSize );
//if( hit==null ){
// pCheck.mallocFailed = 1;
//}else
{
int contentOffset = get2byteNotZero( data, hdr + 5 );
Debug.Assert( contentOffset <= usableSize ); /* Enforced by btreeInitPage() */
Array.Clear( hit, contentOffset, usableSize - contentOffset );//memset(hit+contentOffset, 0, usableSize-contentOffset);
for ( int iLoop = contentOffset - 1; iLoop >= 0; iLoop-- )
hit[iLoop] = 1;//memset(hit, 1, contentOffset);
nCell = get2byte( data, hdr + 3 );
cellStart = hdr + 12 - 4 * pPage.leaf;
for ( i = 0; i < nCell; i++ )
{
int pc = get2byte( data, cellStart + i * 2 );
u32 size = 65536;
int j;
if ( pc <= usableSize - 4 )
{
size = cellSizePtr( pPage, data, pc );
}
if ( (int)( pc + size - 1 ) >= usableSize )
{
checkAppendMsg( pCheck, string.Empty,
"Corruption detected in cell %d on page %d", i, iPage );
}
else
{
for ( j = (int)( pc + size - 1 ); j >= pc; j-- )
hit[j]++;
}
}
i = get2byte( data, hdr + 1 );
while ( i > 0 )
{
int size, j;
Debug.Assert( i <= usableSize - 4 ); /* Enforced by btreeInitPage() */
size = get2byte( data, i + 2 );
Debug.Assert( i + size <= usableSize ); /* Enforced by btreeInitPage() */
for ( j = i + size - 1; j >= i; j-- )
hit[j]++;
j = get2byte( data, i );
Debug.Assert( j == 0 || j > i + size ); /* Enforced by btreeInitPage() */
Debug.Assert( j <= usableSize - 4 ); /* Enforced by btreeInitPage() */
i = j;
}
for ( i = cnt = 0; i < usableSize; i++ )
{
if ( hit[i] == 0 )
{
cnt++;
}
else if ( hit[i] > 1 )
{
checkAppendMsg( pCheck, string.Empty,
"Multiple uses for byte %d of page %d", i, iPage );
break;
}
}
if ( cnt != data[hdr + 7] )
{
checkAppendMsg( pCheck, string.Empty,
"Fragmentation of %d bytes reported as %d on page %d",
cnt, data[hdr + 7], iPage );
}
}
sqlite3PageFree( ref hit );
releasePage( pPage );
return depth + 1;
}
#endif //* SQLITE_OMIT_INTEGRITY_CHECK */
#if !SQLITE_OMIT_INTEGRITY_CHECK
/*
** This routine does a complete check of the given BTree file. aRoot[] is
** an array of pages numbers were each page number is the root page of
** a table. nRoot is the number of entries in aRoot.
**
** A read-only or read-write transaction must be opened before calling
** this function.
**
** Write the number of error seen in pnErr. Except for some memory
** allocation errors, an error message held in memory obtained from
** malloc is returned if pnErr is non-zero. If pnErr==null then NULL is
** returned. If a memory allocation error occurs, NULL is returned.
*/
static string sqlite3BtreeIntegrityCheck(
Btree p, /* The btree to be checked */
int[] aRoot, /* An array of root pages numbers for individual trees */
int nRoot, /* Number of entries in aRoot[] */
int mxErr, /* Stop reporting errors after this many */
ref int pnErr /* Write number of errors seen to this variable */
)
{
Pgno i;
int nRef;
IntegrityCk sCheck = new IntegrityCk();
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
Debug.Assert( p.inTrans > TRANS_NONE && pBt.inTransaction > TRANS_NONE );
nRef = sqlite3PagerRefcount( pBt.pPager );
sCheck.pBt = pBt;
sCheck.pPager = pBt.pPager;
sCheck.nPage = btreePagecount( sCheck.pBt );
sCheck.mxErr = mxErr;
sCheck.nErr = 0;
//sCheck.mallocFailed = 0;
pnErr = 0;
if ( sCheck.nPage == 0 )
{
sqlite3BtreeLeave( p );
return string.Empty;
}
sCheck.anRef = sqlite3Malloc( sCheck.anRef, (int)sCheck.nPage + 1 );
//if( !sCheck.anRef ){
// pnErr = 1;
// sqlite3BtreeLeave(p);
// return 0;
//}
// for (i = 0; i <= sCheck.nPage; i++) { sCheck.anRef[i] = 0; }
i = PENDING_BYTE_PAGE( pBt );
if ( i <= sCheck.nPage )
{
sCheck.anRef[i] = 1;
}
sqlite3StrAccumInit( sCheck.errMsg, null, 1000, 20000 );
//sCheck.errMsg.useMalloc = 2;
/* Check the integrity of the freelist
*/
checkList( sCheck, 1, (int)sqlite3Get4byte( pBt.pPage1.aData, 32 ),
(int)sqlite3Get4byte( pBt.pPage1.aData, 36 ), "Main freelist: " );
/* Check all the tables.
*/
for ( i = 0; (int)i < nRoot && sCheck.mxErr != 0; i++ )
{
if ( aRoot[i] == 0 )
continue;
#if !SQLITE_OMIT_AUTOVACUUM
if ( pBt.autoVacuum && aRoot[i] > 1 )
{
checkPtrmap( sCheck, (u32)aRoot[i], PTRMAP_ROOTPAGE, 0, string.Empty );
}
#endif
checkTreePage( sCheck, aRoot[i], "List of tree roots: ", ref refNULL, ref refNULL, null, null );
}
/* Make sure every page in the file is referenced
*/
for ( i = 1; i <= sCheck.nPage && sCheck.mxErr != 0; i++ )
{
#if SQLITE_OMIT_AUTOVACUUM
if( sCheck.anRef[i]==null ){
checkAppendMsg(sCheck, 0, "Page %d is never used", i);
}
#else
/* If the database supports auto-vacuum, make sure no tables contain
** references to pointer-map pages.
*/
if ( sCheck.anRef[i] == 0 &&
( PTRMAP_PAGENO( pBt, i ) != i || !pBt.autoVacuum ) )
{
checkAppendMsg( sCheck, string.Empty, "Page %d is never used", i );
}
if ( sCheck.anRef[i] != 0 &&
( PTRMAP_PAGENO( pBt, i ) == i && pBt.autoVacuum ) )
{
checkAppendMsg( sCheck, string.Empty, "Pointer map page %d is referenced", i );
}
#endif
}
/* Make sure this analysis did not leave any unref() pages.
** This is an internal consistency check; an integrity check
** of the integrity check.
*/
if ( NEVER( nRef != sqlite3PagerRefcount( pBt.pPager ) ) )
{
checkAppendMsg( sCheck, string.Empty,
"Outstanding page count goes from %d to %d during this analysis",
nRef, sqlite3PagerRefcount( pBt.pPager )
);
}
/* Clean up and report errors.
*/
sqlite3BtreeLeave( p );
sCheck.anRef = null;// sqlite3_free( ref sCheck.anRef );
//if( sCheck.mallocFailed ){
// sqlite3StrAccumReset(sCheck.errMsg);
// pnErr = sCheck.nErr+1;
// return 0;
//}
pnErr = sCheck.nErr;
if ( sCheck.nErr == 0 )
sqlite3StrAccumReset( sCheck.errMsg );
return sqlite3StrAccumFinish( sCheck.errMsg );
}
#endif //* SQLITE_OMIT_INTEGRITY_CHECK */
/*
** Return the full pathname of the underlying database file.
**
** The pager filename is invariant as long as the pager is
** open so it is safe to access without the BtShared mutex.
*/
static string sqlite3BtreeGetFilename( Btree p )
{
Debug.Assert( p.pBt.pPager != null );
return sqlite3PagerFilename( p.pBt.pPager );
}
/*
** Return the pathname of the journal file for this database. The return
** value of this routine is the same regardless of whether the journal file
** has been created or not.
**
** The pager journal filename is invariant as long as the pager is
** open so it is safe to access without the BtShared mutex.
*/
static string sqlite3BtreeGetJournalname( Btree p )
{
Debug.Assert( p.pBt.pPager != null );
return sqlite3PagerJournalname( p.pBt.pPager );
}
/*
** Return non-zero if a transaction is active.
*/
static bool sqlite3BtreeIsInTrans( Btree p )
{
Debug.Assert( p == null || sqlite3_mutex_held( p.db.mutex ) );
return ( p != null && ( p.inTrans == TRANS_WRITE ) );
}
#if !SQLITE_OMIT_WAL
/*
** Run a checkpoint on the Btree passed as the first argument.
**
** Return SQLITE_LOCKED if this or any other connection has an open
** transaction on the shared-cache the argument Btree is connected to.
**
** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
*/
static int sqlite3BtreeCheckpointBtree *p, int eMode, int *pnLog, int *pnCkpt){
int rc = SQLITE_OK;
if( p != null){
BtShared pBt = p.pBt;
sqlite3BtreeEnter(p);
if( pBt.inTransaction!=TRANS_NONE ){
rc = SQLITE_LOCKED;
}else{
rc = sqlite3PagerCheckpoint(pBt.pPager, eMode, pnLog, pnCkpt);
}
sqlite3BtreeLeave(p);
}
return rc;
}
#endif
/*
** Return non-zero if a read (or write) transaction is active.
*/
static bool sqlite3BtreeIsInReadTrans( Btree p )
{
Debug.Assert( p != null );
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
return p.inTrans != TRANS_NONE;
}
static bool sqlite3BtreeIsInBackup( Btree p )
{
Debug.Assert( p != null );
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
return p.nBackup != 0;
}
/*
** This function returns a pointer to a blob of memory associated with
** a single shared-btree. The memory is used by client code for its own
** purposes (for example, to store a high-level schema associated with
** the shared-btree). The btree layer manages reference counting issues.
**
** The first time this is called on a shared-btree, nBytes bytes of memory
** are allocated, zeroed, and returned to the caller. For each subsequent
** call the nBytes parameter is ignored and a pointer to the same blob
** of memory returned.
**
** If the nBytes parameter is 0 and the blob of memory has not yet been
** allocated, a null pointer is returned. If the blob has already been
** allocated, it is returned as normal.
**
** Just before the shared-btree is closed, the function passed as the
** xFree argument when the memory allocation was made is invoked on the
** blob of allocated memory. The xFree function should not call sqlite3_free()
** on the memory, the btree layer does that.
*/
static Schema sqlite3BtreeSchema( Btree p, int nBytes, dxFreeSchema xFree )
{
BtShared pBt = p.pBt;
sqlite3BtreeEnter( p );
if ( null == pBt.pSchema && nBytes != 0 )
{
pBt.pSchema = new Schema();//sqlite3DbMallocZero(0, nBytes);
pBt.xFreeSchema = xFree;
}
sqlite3BtreeLeave( p );
return pBt.pSchema;
}
/*
** Return SQLITE_LOCKED_SHAREDCACHE if another user of the same shared
** btree as the argument handle holds an exclusive lock on the
** sqlite_master table. Otherwise SQLITE_OK.
*/
static int sqlite3BtreeSchemaLocked( Btree p )
{
int rc;
Debug.Assert( sqlite3_mutex_held( p.db.mutex ) );
sqlite3BtreeEnter( p );
rc = querySharedCacheTableLock( p, MASTER_ROOT, READ_LOCK );
Debug.Assert( rc == SQLITE_OK || rc == SQLITE_LOCKED_SHAREDCACHE );
sqlite3BtreeLeave( p );
return rc;
}
#if !SQLITE_OMIT_SHARED_CACHE
/*
** Obtain a lock on the table whose root page is iTab. The
** lock is a write lock if isWritelock is true or a read lock
** if it is false.
*/
int sqlite3BtreeLockTable(Btree p, int iTab, u8 isWriteLock){
int rc = SQLITE_OK;
Debug.Assert( p.inTrans!=TRANS_NONE );
if( p.sharable ){
u8 lockType = READ_LOCK + isWriteLock;
Debug.Assert( READ_LOCK+1==WRITE_LOCK );
Debug.Assert( isWriteLock==null || isWriteLock==1 );
sqlite3BtreeEnter(p);
rc = querySharedCacheTableLock(p, iTab, lockType);
if( rc==SQLITE_OK ){
rc = setSharedCacheTableLock(p, iTab, lockType);
}
sqlite3BtreeLeave(p);
}
return rc;
}
#endif
#if !SQLITE_OMIT_INCRBLOB
/*
** Argument pCsr must be a cursor opened for writing on an
** INTKEY table currently pointing at a valid table entry.
** This function modifies the data stored as part of that entry.
**
** Only the data content may only be modified, it is not possible to
** change the length of the data stored. If this function is called with
** parameters that attempt to write past the end of the existing data,
** no modifications are made and SQLITE_CORRUPT is returned.
*/
int sqlite3BtreePutData(BtCursor pCsr, u32 offset, u32 amt, void *z){
int rc;
Debug.Assert( cursorHoldsMutex(pCsr) );
Debug.Assert( sqlite3_mutex_held(pCsr.pBtree.db.mutex) );
Debug.Assert( pCsr.isIncrblobHandle );
rc = restoreCursorPosition(pCsr);
if( rc!=SQLITE_OK ){
return rc;
}
Debug.Assert( pCsr.eState!=CURSOR_REQUIRESEEK );
if( pCsr.eState!=CURSOR_VALID ){
return SQLITE_ABORT;
}
/* Check some assumptions:
** (a) the cursor is open for writing,
** (b) there is a read/write transaction open,
** (c) the connection holds a write-lock on the table (if required),
** (d) there are no conflicting read-locks, and
** (e) the cursor points at a valid row of an intKey table.
*/
if( !pCsr.wrFlag ){
return SQLITE_READONLY;
}
Debug.Assert( !pCsr.pBt.readOnly && pCsr.pBt.inTransaction==TRANS_WRITE );
Debug.Assert( hasSharedCacheTableLock(pCsr.pBtree, pCsr.pgnoRoot, 0, 2) );
Debug.Assert( !hasReadConflicts(pCsr.pBtree, pCsr.pgnoRoot) );
Debug.Assert( pCsr.apPage[pCsr.iPage].intKey );
return accessPayload(pCsr, offset, amt, (byte[] *)z, 1);
}
/*
** Set a flag on this cursor to cache the locations of pages from the
** overflow list for the current row. This is used by cursors opened
** for incremental blob IO only.
**
** This function sets a flag only. The actual page location cache
** (stored in BtCursor.aOverflow[]) is allocated and used by function
** accessPayload() (the worker function for sqlite3BtreeData() and
** sqlite3BtreePutData()).
*/
static void sqlite3BtreeCacheOverflow(BtCursor pCur){
Debug.Assert( cursorHoldsMutex(pCur) );
Debug.Assert( sqlite3_mutex_held(pCur.pBtree.db.mutex) );
invalidateOverflowCache(pCur)
pCur.isIncrblobHandle = 1;
}
#endif
/*
** Set both the "read version" (single byte at byte offset 18) and
** "write version" (single byte at byte offset 19) fields in the database
** header to iVersion.
*/
static int sqlite3BtreeSetVersion( Btree pBtree, int iVersion )
{
BtShared pBt = pBtree.pBt;
int rc; /* Return code */
Debug.Assert( pBtree.inTrans == TRANS_NONE );
Debug.Assert( iVersion == 1 || iVersion == 2 );
/* If setting the version fields to 1, do not automatically open the
** WAL connection, even if the version fields are currently set to 2.
*/
pBt.doNotUseWAL = iVersion == 1;
rc = sqlite3BtreeBeginTrans( pBtree, 0 );
if ( rc == SQLITE_OK )
{
u8[] aData = pBt.pPage1.aData;
if ( aData[18] != (u8)iVersion || aData[19] != (u8)iVersion )
{
rc = sqlite3BtreeBeginTrans( pBtree, 2 );
if ( rc == SQLITE_OK )
{
rc = sqlite3PagerWrite( pBt.pPage1.pDbPage );
if ( rc == SQLITE_OK )
{
aData[18] = (u8)iVersion;
aData[19] = (u8)iVersion;
}
}
}
}
pBt.doNotUseWAL = false;
return rc;
}
}
}