wasCSharpSQLite – Rev 1
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using System;
using System.Diagnostics;
using i16 = System.Int16;
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.
** For a detailed discussion of BTrees, refer to
**
** Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
** "Sorting And Searching", pages 473-480. Addison-Wesley
** Publishing Company, Reading, Massachusetts.
**
** The basic idea is that each page of the file contains N database
** entries and N+1 pointers to subpages.
**
** ----------------------------------------------------------------
** | Ptr(0) | Key(0) | Ptr(1) | Key(1) | ... | Key(N-1) | Ptr(N) |
** ----------------------------------------------------------------
**
** All of the keys on the page that Ptr(0) points to have values less
** than Key(0). All of the keys on page Ptr(1) and its subpages have
** values greater than Key(0) and less than Key(1). All of the keys
** on Ptr(N) and its subpages have values greater than Key(N-1). And
** so forth.
**
** Finding a particular key requires reading O(log(M)) pages from the
** disk where M is the number of entries in the tree.
**
** In this implementation, a single file can hold one or more separate
** BTrees. Each BTree is identified by the index of its root page. The
** key and data for any entry are combined to form the "payload". A
** fixed amount of payload can be carried directly on the database
** page. If the payload is larger than the preset amount then surplus
** bytes are stored on overflow pages. The payload for an entry
** and the preceding pointer are combined to form a "Cell". Each
** page has a small header which contains the Ptr(N) pointer and other
** information such as the size of key and data.
**
** FORMAT DETAILS
**
** The file is divided into pages. The first page is called page 1,
** the second is page 2, and so forth. A page number of zero indicates
** "no such page". The page size can be any power of 2 between 512 and 65536.
** Each page can be either a btree page, a freelist page, an overflow
** page, or a pointer-map page.
**
** The first page is always a btree page. The first 100 bytes of the first
** page contain a special header (the "file header") that describes the file.
** The format of the file header is as follows:
**
** OFFSET SIZE DESCRIPTION
** 0 16 Header string: "SQLite format 3\000"
** 16 2 Page size in bytes.
** 18 1 File format write version
** 19 1 File format read version
** 20 1 Bytes of unused space at the end of each page
** 21 1 Max embedded payload fraction
** 22 1 Min embedded payload fraction
** 23 1 Min leaf payload fraction
** 24 4 File change counter
** 28 4 Reserved for future use
** 32 4 First freelist page
** 36 4 Number of freelist pages in the file
** 40 60 15 4-byte meta values passed to higher layers
**
** 40 4 Schema cookie
** 44 4 File format of schema layer
** 48 4 Size of page cache
** 52 4 Largest root-page (auto/incr_vacuum)
** 56 4 1=UTF-8 2=UTF16le 3=UTF16be
** 60 4 User version
** 64 4 Incremental vacuum mode
** 68 4 unused
** 72 4 unused
** 76 4 unused
**
** All of the integer values are big-endian (most significant byte first).
**
** The file change counter is incremented when the database is changed
** This counter allows other processes to know when the file has changed
** and thus when they need to flush their cache.
**
** The max embedded payload fraction is the amount of the total usable
** space in a page that can be consumed by a single cell for standard
** B-tree (non-LEAFDATA) tables. A value of 255 means 100%. The default
** is to limit the maximum cell size so that at least 4 cells will fit
** on one page. Thus the default max embedded payload fraction is 64.
**
** If the payload for a cell is larger than the max payload, then extra
** payload is spilled to overflow pages. Once an overflow page is allocated,
** as many bytes as possible are moved into the overflow pages without letting
** the cell size drop below the min embedded payload fraction.
**
** The min leaf payload fraction is like the min embedded payload fraction
** except that it applies to leaf nodes in a LEAFDATA tree. The maximum
** payload fraction for a LEAFDATA tree is always 100% (or 255) and it
** not specified in the header.
**
** Each btree pages is divided into three sections: The header, the
** cell pointer array, and the cell content area. Page 1 also has a 100-byte
** file header that occurs before the page header.
**
** |----------------|
** | file header | 100 bytes. Page 1 only.
** |----------------|
** | page header | 8 bytes for leaves. 12 bytes for interior nodes
** |----------------|
** | cell pointer | | 2 bytes per cell. Sorted order.
** | array | | Grows downward
** | | v
** |----------------|
** | unallocated |
** | space |
** |----------------| ^ Grows upwards
** | cell content | | Arbitrary order interspersed with freeblocks.
** | area | | and free space fragments.
** |----------------|
**
** The page headers looks like this:
**
** OFFSET SIZE DESCRIPTION
** 0 1 Flags. 1: intkey, 2: zerodata, 4: leafdata, 8: leaf
** 1 2 byte offset to the first freeblock
** 3 2 number of cells on this page
** 5 2 first byte of the cell content area
** 7 1 number of fragmented free bytes
** 8 4 Right child (the Ptr(N) value). Omitted on leaves.
**
** The flags define the format of this btree page. The leaf flag means that
** this page has no children. The zerodata flag means that this page carries
** only keys and no data. The intkey flag means that the key is a integer
** which is stored in the key size entry of the cell header rather than in
** the payload area.
**
** The cell pointer array begins on the first byte after the page header.
** The cell pointer array contains zero or more 2-byte numbers which are
** offsets from the beginning of the page to the cell content in the cell
** content area. The cell pointers occur in sorted order. The system strives
** to keep free space after the last cell pointer so that new cells can
** be easily added without having to defragment the page.
**
** Cell content is stored at the very end of the page and grows toward the
** beginning of the page.
**
** Unused space within the cell content area is collected into a linked list of
** freeblocks. Each freeblock is at least 4 bytes in size. The byte offset
** to the first freeblock is given in the header. Freeblocks occur in
** increasing order. Because a freeblock must be at least 4 bytes in size,
** any group of 3 or fewer unused bytes in the cell content area cannot
** exist on the freeblock chain. A group of 3 or fewer free bytes is called
** a fragment. The total number of bytes in all fragments is recorded.
** in the page header at offset 7.
**
** SIZE DESCRIPTION
** 2 Byte offset of the next freeblock
** 2 Bytes in this freeblock
**
** Cells are of variable length. Cells are stored in the cell content area at
** the end of the page. Pointers to the cells are in the cell pointer array
** that immediately follows the page header. Cells is not necessarily
** contiguous or in order, but cell pointers are contiguous and in order.
**
** Cell content makes use of variable length integers. A variable
** length integer is 1 to 9 bytes where the lower 7 bits of each
** byte are used. The integer consists of all bytes that have bit 8 set and
** the first byte with bit 8 clear. The most significant byte of the integer
** appears first. A variable-length integer may not be more than 9 bytes long.
** As a special case, all 8 bytes of the 9th byte are used as data. This
** allows a 64-bit integer to be encoded in 9 bytes.
**
** 0x00 becomes 0x00000000
** 0x7f becomes 0x0000007f
** 0x81 0x00 becomes 0x00000080
** 0x82 0x00 becomes 0x00000100
** 0x80 0x7f becomes 0x0000007f
** 0x8a 0x91 0xd1 0xac 0x78 becomes 0x12345678
** 0x81 0x81 0x81 0x81 0x01 becomes 0x10204081
**
** Variable length integers are used for rowids and to hold the number of
** bytes of key and data in a btree cell.
**
** The content of a cell looks like this:
**
** SIZE DESCRIPTION
** 4 Page number of the left child. Omitted if leaf flag is set.
** var Number of bytes of data. Omitted if the zerodata flag is set.
** var Number of bytes of key. Or the key itself if intkey flag is set.
** * Payload
** 4 First page of the overflow chain. Omitted if no overflow
**
** Overflow pages form a linked list. Each page except the last is completely
** filled with data (pagesize - 4 bytes). The last page can have as little
** as 1 byte of data.
**
** SIZE DESCRIPTION
** 4 Page number of next overflow page
** * Data
**
** Freelist pages come in two subtypes: trunk pages and leaf pages. The
** file header points to the first in a linked list of trunk page. Each trunk
** page points to multiple leaf pages. The content of a leaf page is
** unspecified. A trunk page looks like this:
**
** SIZE DESCRIPTION
** 4 Page number of next trunk page
** 4 Number of leaf pointers on this page
** * zero or more pages numbers of leaves
*************************************************************************
** 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: 2011-05-19 13:26:54 ed1da510a239ea767a01dc332b667119fa3c908e
**
*************************************************************************
*/
//#include "sqliteInt.h"
/* The following value is the maximum cell size assuming a maximum page
** size give above.
*/
//#define MX_CELL_SIZE(pBt) ((int)(pBt->pageSize-8))
static int MX_CELL_SIZE( BtShared pBt )
{
return (int)( pBt.pageSize - 8 );
}
/* The maximum number of cells on a single page of the database. This
** assumes a minimum cell size of 6 bytes (4 bytes for the cell itself
** plus 2 bytes for the index to the cell in the page header). Such
** small cells will be rare, but they are possible.
*/
//#define MX_CELL(pBt) ((pBt.pageSize-8)/6)
static int MX_CELL( BtShared pBt )
{
return ( (int)( pBt.pageSize - 8 ) / 6 );
}
/* Forward declarations */
//typedef struct MemPage MemPage;
//typedef struct BtLock BtLock;
/*
** This is a magic string that appears at the beginning of every
** SQLite database in order to identify the file as a real database.
**
** You can change this value at compile-time by specifying a
** -DSQLITE_FILE_HEADER="..." on the compiler command-line. The
** header must be exactly 16 bytes including the zero-terminator so
** the string itself should be 15 characters long. If you change
** the header, then your custom library will not be able to read
** databases generated by the standard tools and the standard tools
** will not be able to read databases created by your custom library.
*/
#if !SQLITE_FILE_HEADER //* 123456789 123456 */
const string SQLITE_FILE_HEADER = "SQLite format 3\0";
#endif
/*
** Page type flags. An ORed combination of these flags appear as the
** first byte of on-disk image of every BTree page.
*/
const byte PTF_INTKEY = 0x01;
const byte PTF_ZERODATA = 0x02;
const byte PTF_LEAFDATA = 0x04;
const byte PTF_LEAF = 0x08;
/*
** As each page of the file is loaded into memory, an instance of the following
** structure is appended and initialized to zero. This structure stores
** information about the page that is decoded from the raw file page.
**
** The pParent field points back to the parent page. This allows us to
** walk up the BTree from any leaf to the root. Care must be taken to
** unref() the parent page pointer when this page is no longer referenced.
** The pageDestructor() routine handles that chore.
**
** Access to all fields of this structure is controlled by the mutex
** stored in MemPage.pBt.mutex.
*/
public struct _OvflCell
{ /* Cells that will not fit on aData[] */
public u8[] pCell; /* Pointers to the body of the overflow cell */
public u16 idx; /* Insert this cell before idx-th non-overflow cell */
public _OvflCell Copy()
{
_OvflCell cp = new _OvflCell();
if ( pCell != null )
{
cp.pCell = sqlite3Malloc( pCell.Length );
Buffer.BlockCopy( pCell, 0, cp.pCell, 0, pCell.Length );
}
cp.idx = idx;
return cp;
}
};
public class MemPage
{
public u8 isInit; /* True if previously initialized. MUST BE FIRST! */
public u8 nOverflow; /* Number of overflow cell bodies in aCell[] */
public u8 intKey; /* True if u8key flag is set */
public u8 leaf; /* 1 if leaf flag is set */
public u8 hasData; /* True if this page stores data */
public u8 hdrOffset; /* 100 for page 1. 0 otherwise */
public u8 childPtrSize; /* 0 if leaf==1. 4 if leaf==0 */
public u16 maxLocal; /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
public u16 minLocal; /* Copy of BtShared.minLocal or BtShared.minLeaf */
public u16 cellOffset; /* Index in aData of first cell pou16er */
public u16 nFree; /* Number of free bytes on the page */
public u16 nCell; /* Number of cells on this page, local and ovfl */
public u16 maskPage; /* Mask for page offset */
public _OvflCell[] aOvfl = new _OvflCell[5];
public BtShared pBt; /* Pointer to BtShared that this page is part of */
public byte[] aData; /* Pointer to disk image of the page data */
public DbPage pDbPage; /* Pager page handle */
public Pgno pgno; /* Page number for this page */
//public byte[] aData
//{
// get
// {
// Debug.Assert( pgno != 1 || pDbPage.pData == _aData );
// return _aData;
// }
// set
// {
// _aData = value;
// Debug.Assert( pgno != 1 || pDbPage.pData == _aData );
// }
//}
public MemPage Copy()
{
MemPage cp = (MemPage)MemberwiseClone();
if ( aOvfl != null )
{
cp.aOvfl = new _OvflCell[aOvfl.Length];
for ( int i = 0; i < aOvfl.Length; i++ )
cp.aOvfl[i] = aOvfl[i].Copy();
}
if ( aData != null )
{
cp.aData = sqlite3Malloc( aData.Length );
Buffer.BlockCopy( aData, 0, cp.aData, 0, aData.Length );
}
return cp;
}
};
/*
** The in-memory image of a disk page has the auxiliary information appended
** to the end. EXTRA_SIZE is the number of bytes of space needed to hold
** that extra information.
*/
const int EXTRA_SIZE = 0;// No used in C#, since we use create a class; was MemPage.Length;
/*
** A linked list of the following structures is stored at BtShared.pLock.
** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor
** is opened on the table with root page BtShared.iTable. Locks are removed
** from this list when a transaction is committed or rolled back, or when
** a btree handle is closed.
*/
public class BtLock
{
Btree pBtree; /* Btree handle holding this lock */
Pgno iTable; /* Root page of table */
u8 eLock; /* READ_LOCK or WRITE_LOCK */
BtLock pNext; /* Next in BtShared.pLock list */
};
/* Candidate values for BtLock.eLock */
//#define READ_LOCK 1
//#define WRITE_LOCK 2
const int READ_LOCK = 1;
const int WRITE_LOCK = 2;
/* A Btree handle
**
** A database connection contains a pointer to an instance of
** this object for every database file that it has open. This structure
** is opaque to the database connection. The database connection cannot
** see the internals of this structure and only deals with pointers to
** this structure.
**
** For some database files, the same underlying database cache might be
** shared between multiple connections. In that case, each connection
** has it own instance of this object. But each instance of this object
** points to the same BtShared object. The database cache and the
** schema associated with the database file are all contained within
** the BtShared object.
**
** All fields in this structure are accessed under sqlite3.mutex.
** The pBt pointer itself may not be changed while there exists cursors
** in the referenced BtShared that point back to this Btree since those
** cursors have to go through this Btree to find their BtShared and
** they often do so without holding sqlite3.mutex.
*/
public class Btree
{
public sqlite3 db; /* The database connection holding this Btree */
public BtShared pBt; /* Sharable content of this Btree */
public u8 inTrans; /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
public bool sharable; /* True if we can share pBt with another db */
public bool locked; /* True if db currently has pBt locked */
public int wantToLock; /* Number of nested calls to sqlite3BtreeEnter() */
public int nBackup; /* Number of backup operations reading this btree */
public Btree pNext; /* List of other sharable Btrees from the same db */
public Btree pPrev; /* Back pointer of the same list */
#if !SQLITE_OMIT_SHARED_CACHE
BtLock lock; /* Object used to lock page 1 */
#endif
};
/*
** Btree.inTrans may take one of the following values.
**
** If the shared-data extension is enabled, there may be multiple users
** of the Btree structure. At most one of these may open a write transaction,
** but any number may have active read transactions.
*/
const byte TRANS_NONE = 0;
const byte TRANS_READ = 1;
const byte TRANS_WRITE = 2;
/*
** An instance of this object represents a single database file.
**
** A single database file can be in use as the same time by two
** or more database connections. When two or more connections are
** sharing the same database file, each connection has it own
** private Btree object for the file and each of those Btrees points
** to this one BtShared object. BtShared.nRef is the number of
** connections currently sharing this database file.
**
** Fields in this structure are accessed under the BtShared.mutex
** mutex, except for nRef and pNext which are accessed under the
** global SQLITE_MUTEX_STATIC_MASTER mutex. The pPager field
** may not be modified once it is initially set as long as nRef>0.
** The pSchema field may be set once under BtShared.mutex and
** thereafter is unchanged as long as nRef>0.
**
** isPending:
**
** If a BtShared client fails to obtain a write-lock on a database
** table (because there exists one or more read-locks on the table),
** the shared-cache enters 'pending-lock' state and isPending is
** set to true.
**
** The shared-cache leaves the 'pending lock' state when either of
** the following occur:
**
** 1) The current writer (BtShared.pWriter) concludes its transaction, OR
** 2) The number of locks held by other connections drops to zero.
**
** while in the 'pending-lock' state, no connection may start a new
** transaction.
**
** This feature is included to help prevent writer-starvation.
*/
public class BtShared
{
public Pager pPager; /* The page cache */
public sqlite3 db; /* Database connection currently using this Btree */
public BtCursor pCursor; /* A list of all open cursors */
public MemPage pPage1; /* First page of the database */
public bool readOnly; /* True if the underlying file is readonly */
public bool pageSizeFixed; /* True if the page size can no longer be changed */
public bool secureDelete; /* True if secure_delete is enabled */
public bool initiallyEmpty; /* Database is empty at start of transaction */
public u8 openFlags; /* Flags to sqlite3BtreeOpen() */
#if !SQLITE_OMIT_AUTOVACUUM
public bool autoVacuum; /* True if auto-vacuum is enabled */
public bool incrVacuum; /* True if incr-vacuum is enabled */
#endif
public u8 inTransaction; /* Transaction state */
public bool doNotUseWAL; /* If true, do not open write-ahead-log file */
public u16 maxLocal; /* Maximum local payload in non-LEAFDATA tables */
public u16 minLocal; /* Minimum local payload in non-LEAFDATA tables */
public u16 maxLeaf; /* Maximum local payload in a LEAFDATA table */
public u16 minLeaf; /* Minimum local payload in a LEAFDATA table */
public u32 pageSize; /* Total number of bytes on a page */
public u32 usableSize; /* Number of usable bytes on each page */
public int nTransaction; /* Number of open transactions (read + write) */
public Pgno nPage; /* Number of pages in the database */
public Schema pSchema; /* Pointer to space allocated by sqlite3BtreeSchema() */
public dxFreeSchema xFreeSchema;/* Destructor for BtShared.pSchema */
public sqlite3_mutex mutex; /* Non-recursive mutex required to access this object */
public Bitvec pHasContent; /* Set of pages moved to free-list this transaction */
#if !SQLITE_OMIT_SHARED_CACHE
public int nRef; /* Number of references to this structure */
public BtShared pNext; /* Next on a list of sharable BtShared structs */
public BtLock pLock; /* List of locks held on this shared-btree struct */
public Btree pWriter; /* Btree with currently open write transaction */
public u8 isExclusive; /* True if pWriter has an EXCLUSIVE lock on the db */
public u8 isPending; /* If waiting for read-locks to clear */
#endif
public byte[] pTmpSpace; /* BtShared.pageSize bytes of space for tmp use */
};
/*
** An instance of the following structure is used to hold information
** about a cell. The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/
//typedef struct CellInfo CellInfo;
public struct CellInfo
{
public int iCell; /* Offset to start of cell content -- Needed for C# */
public byte[] pCell; /* Pointer to the start of cell content */
public i64 nKey; /* The key for INTKEY tables, or number of bytes in key */
public u32 nData; /* Number of bytes of data */
public u32 nPayload; /* Total amount of payload */
public u16 nHeader; /* Size of the cell content header in bytes */
public u16 nLocal; /* Amount of payload held locally */
public u16 iOverflow; /* Offset to overflow page number. Zero if no overflow */
public u16 nSize; /* Size of the cell content on the main b-tree page */
public bool Equals( CellInfo ci )
{
if ( ci.iCell >= ci.pCell.Length || iCell >= this.pCell.Length )
return false;
if ( ci.pCell[ci.iCell] != this.pCell[iCell] )
return false;
if ( ci.nKey != this.nKey || ci.nData != this.nData || ci.nPayload != this.nPayload )
return false;
if ( ci.nHeader != this.nHeader || ci.nLocal != this.nLocal )
return false;
if ( ci.iOverflow != this.iOverflow || ci.nSize != this.nSize )
return false;
return true;
}
};
/*
** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
** this will be declared corrupt. This value is calculated based on a
** maximum database size of 2^31 pages a minimum fanout of 2 for a
** root-node and 3 for all other internal nodes.
**
** If a tree that appears to be taller than this is encountered, it is
** assumed that the database is corrupt.
*/
//#define BTCURSOR_MAX_DEPTH 20
const int BTCURSOR_MAX_DEPTH = 20;
/*
** A cursor is a pointer to a particular entry within a particular
** b-tree within a database file.
**
** The entry is identified by its MemPage and the index in
** MemPage.aCell[] of the entry.
**
** A single database file can shared by two more database connections,
** but cursors cannot be shared. Each cursor is associated with a
** particular database connection identified BtCursor.pBtree.db.
**
** Fields in this structure are accessed under the BtShared.mutex
** found at self.pBt.mutex.
*/
public class BtCursor
{
public Btree pBtree; /* The Btree to which this cursor belongs */
public BtShared pBt; /* The BtShared this cursor points to */
public BtCursor pNext;
public BtCursor pPrev; /* Forms a linked list of all cursors */
public KeyInfo pKeyInfo; /* Argument passed to comparison function */
public Pgno pgnoRoot; /* The root page of this tree */
public sqlite3_int64 cachedRowid; /* Next rowid cache. 0 means not valid */
public CellInfo info = new CellInfo(); /* A parse of the cell we are pointing at */
public byte[] pKey; /* Saved key that was cursor's last known position */
public i64 nKey; /* Size of pKey, or last integer key */
public int skipNext; /* Prev() is noop if negative. Next() is noop if positive */
public u8 wrFlag; /* True if writable */
public u8 atLast; /* VdbeCursor pointing to the last entry */
public bool validNKey; /* True if info.nKey is valid */
public int eState; /* One of the CURSOR_XXX constants (see below) */
#if !SQLITE_OMIT_INCRBLOB
public Pgno[] aOverflow; /* Cache of overflow page locations */
public bool isIncrblobHandle; /* True if this cursor is an incr. io handle */
#endif
public i16 iPage; /* Index of current page in apPage */
public u16[] aiIdx = new u16[BTCURSOR_MAX_DEPTH]; /* Current index in apPage[i] */
public MemPage[] apPage = new MemPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
public void Clear()
{
pNext = null;
pPrev = null;
pKeyInfo = null;
pgnoRoot = 0;
cachedRowid = 0;
info = new CellInfo();
wrFlag = 0;
atLast = 0;
validNKey = false;
eState = 0;
pKey = null;
nKey = 0;
skipNext = 0;
#if !SQLITE_OMIT_INCRBLOB
isIncrblobHandle=false;
aOverflow= null;
#endif
iPage = 0;
}
public BtCursor Copy()
{
BtCursor cp = (BtCursor)MemberwiseClone();
return cp;
}
};
/*
** Potential values for BtCursor.eState.
**
** CURSOR_VALID:
** VdbeCursor points to a valid entry. getPayload() etc. may be called.
**
** CURSOR_INVALID:
** VdbeCursor does not point to a valid entry. This can happen (for example)
** because the table is empty or because BtreeCursorFirst() has not been
** called.
**
** CURSOR_REQUIRESEEK:
** The table that this cursor was opened on still exists, but has been
** modified since the cursor was last used. The cursor position is saved
** in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in
** this state, restoreCursorPosition() can be called to attempt to
** seek the cursor to the saved position.
**
** CURSOR_FAULT:
** A unrecoverable error (an I/O error or a malloc failure) has occurred
** on a different connection that shares the BtShared cache with this
** cursor. The error has left the cache in an inconsistent state.
** Do nothing else with this cursor. Any attempt to use the cursor
** should return the error code stored in BtCursor.skip
*/
const int CURSOR_INVALID = 0;
const int CURSOR_VALID = 1;
const int CURSOR_REQUIRESEEK = 2;
const int CURSOR_FAULT = 3;
/*
** The database page the PENDING_BYTE occupies. This page is never used.
*/
//# define PENDING_BYTE_PAGE(pBt) PAGER_MJ_PGNO(pBt)
// TODO -- Convert PENDING_BYTE_PAGE to inline
static u32 PENDING_BYTE_PAGE( BtShared pBt )
{
return (u32)PAGER_MJ_PGNO( pBt.pPager );
}
/*
** These macros define the location of the pointer-map entry for a
** database page. The first argument to each is the number of usable
** bytes on each page of the database (often 1024). The second is the
** page number to look up in the pointer map.
**
** PTRMAP_PAGENO returns the database page number of the pointer-map
** page that stores the required pointer. PTRMAP_PTROFFSET returns
** the offset of the requested map entry.
**
** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
** this test.
*/
//#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno)
static Pgno PTRMAP_PAGENO( BtShared pBt, Pgno pgno )
{
return ptrmapPageno( pBt, pgno );
}
//#define PTRMAP_PTROFFSET(pgptrmap, pgno) (5*(pgno-pgptrmap-1))
static u32 PTRMAP_PTROFFSET( u32 pgptrmap, u32 pgno )
{
return ( 5 * ( pgno - pgptrmap - 1 ) );
}
//#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno))
static bool PTRMAP_ISPAGE( BtShared pBt, u32 pgno )
{
return ( PTRMAP_PAGENO( ( pBt ), ( pgno ) ) == ( pgno ) );
}
/*
** The pointer map is a lookup table that identifies the parent page for
** each child page in the database file. The parent page is the page that
** contains a pointer to the child. Every page in the database contains
** 0 or 1 parent pages. (In this context 'database page' refers
** to any page that is not part of the pointer map itself.) Each pointer map
** entry consists of a single byte 'type' and a 4 byte parent page number.
** The PTRMAP_XXX identifiers below are the valid types.
**
** The purpose of the pointer map is to facility moving pages from one
** position in the file to another as part of autovacuum. When a page
** is moved, the pointer in its parent must be updated to point to the
** new location. The pointer map is used to locate the parent page quickly.
**
** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not
** used in this case.
**
** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number
** is not used in this case.
**
** PTRMAP_OVERFLOW1: The database page is the first page in a list of
** overflow pages. The page number identifies the page that
** contains the cell with a pointer to this overflow page.
**
** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of
** overflow pages. The page-number identifies the previous
** page in the overflow page list.
**
** PTRMAP_BTREE: The database page is a non-root btree page. The page number
** identifies the parent page in the btree.
*/
//#define PTRMAP_ROOTPAGE 1
//#define PTRMAP_FREEPAGE 2
//#define PTRMAP_OVERFLOW1 3
//#define PTRMAP_OVERFLOW2 4
//#define PTRMAP_BTREE 5
const int PTRMAP_ROOTPAGE = 1;
const int PTRMAP_FREEPAGE = 2;
const int PTRMAP_OVERFLOW1 = 3;
const int PTRMAP_OVERFLOW2 = 4;
const int PTRMAP_BTREE = 5;
/* A bunch of Debug.Assert() statements to check the transaction state variables
** of handle p (type Btree*) are internally consistent.
*/
#if DEBUG
//#define btreeIntegrity(p) \
// Debug.Assert( p.pBt.inTransaction!=TRANS_NONE || p.pBt.nTransaction==0 ); \
// Debug.Assert( p.pBt.inTransaction>=p.inTrans );
static void btreeIntegrity( Btree p )
{
Debug.Assert( p.pBt.inTransaction != TRANS_NONE || p.pBt.nTransaction == 0 );
Debug.Assert( p.pBt.inTransaction >= p.inTrans );
}
#else
static void btreeIntegrity(Btree p) { }
#endif
/*
** The ISAUTOVACUUM macro is used within balance_nonroot() to determine
** if the database supports auto-vacuum or not. Because it is used
** within an expression that is an argument to another macro
** (sqliteMallocRaw), it is not possible to use conditional compilation.
** So, this macro is defined instead.
*/
#if !SQLITE_OMIT_AUTOVACUUM
//#define ISAUTOVACUUM (pBt.autoVacuum)
#else
//#define ISAUTOVACUUM 0
public static bool ISAUTOVACUUM =false;
#endif
/*
** This structure is passed around through all the sanity checking routines
** in order to keep track of some global state information.
*/
//typedef struct IntegrityCk IntegrityCk;
public class IntegrityCk
{
public BtShared pBt; /* The tree being checked out */
public Pager pPager; /* The associated pager. Also accessible by pBt.pPager */
public Pgno nPage; /* Number of pages in the database */
public int[] anRef; /* Number of times each page is referenced */
public int mxErr; /* Stop accumulating errors when this reaches zero */
public int nErr; /* Number of messages written to zErrMsg so far */
//public int mallocFailed; /* A memory allocation error has occurred */
public StrAccum errMsg = new StrAccum( 100 ); /* Accumulate the error message text here */
};
/*
** Read or write a two- and four-byte big-endian integer values.
*/
//#define get2byte(x) ((x)[0]<<8 | (x)[1])
static int get2byte( byte[] p, int offset )
{
return p[offset + 0] << 8 | p[offset + 1];
}
//#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
static void put2byte( byte[] pData, int Offset, u32 v )
{
pData[Offset + 0] = (byte)( v >> 8 );
pData[Offset + 1] = (byte)v;
}
static void put2byte( byte[] pData, int Offset, int v )
{
pData[Offset + 0] = (byte)( v >> 8 );
pData[Offset + 1] = (byte)v;
}
//#define get4byte sqlite3Get4byte
//#define put4byte sqlite3Put4byte
}
}