wasCSharpSQLite – Rev 1
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using System;
using System.Diagnostics;
using System.Text;
using Bitmask = System.UInt64;
using i16 = System.Int16;
using u8 = System.Byte;
using u16 = System.UInt16;
using u32 = System.UInt32;
#if !SQLITE_MAX_VARIABLE_NUMBER
using ynVar = System.Int16;
#else
using ynVar = System.Int32;
#endif
namespace Community.CsharpSqlite
{
using sqlite3_value = Sqlite3.Mem;
public partial class Sqlite3
{
/*
** 2008 August 18
**
** 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 contains routines used for walking the parser tree and
** resolve all identifiers by associating them with a particular
** table and column.
*************************************************************************
** 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: 2010-08-23 18:52:01 42537b60566f288167f1b5864a5435986838e3a3
**
*************************************************************************
*/
//#include "sqliteInt.h"
//#include <stdlib.h>
//#include <string.h>
/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
** If the result set column is a simple column reference, then this routine
** makes an exact copy. But for any other kind of expression, this
** routine make a copy of the result set column as the argument to the
** TK_AS operator. The TK_AS operator causes the expression to be
** evaluated just once and then reused for each alias.
**
** The reason for suppressing the TK_AS term when the expression is a simple
** column reference is so that the column reference will be recognized as
** usable by indices within the WHERE clause processing logic.
**
** Hack: The TK_AS operator is inhibited if zType[0]=='G'. This means
** that in a GROUP BY clause, the expression is evaluated twice. Hence:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x
**
** Is equivalent to:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set. We might fix this someday. Or
** then again, we might not...
*/
static void resolveAlias(
Parse pParse, /* Parsing context */
ExprList pEList, /* A result set */
int iCol, /* A column in the result set. 0..pEList.nExpr-1 */
Expr pExpr, /* Transform this into an alias to the result set */
string zType /* "GROUP" or "ORDER" or "" */
)
{
Expr pOrig; /* The iCol-th column of the result set */
Expr pDup; /* Copy of pOrig */
sqlite3 db; /* The database connection */
Debug.Assert( iCol >= 0 && iCol < pEList.nExpr );
pOrig = pEList.a[iCol].pExpr;
Debug.Assert( pOrig != null );
Debug.Assert( ( pOrig.flags & EP_Resolved ) != 0 );
db = pParse.db;
if ( pOrig.op != TK_COLUMN && ( zType.Length == 0 || zType[0] != 'G' ) )
{
pDup = sqlite3ExprDup( db, pOrig, 0 );
pDup = sqlite3PExpr( pParse, TK_AS, pDup, null, null );
if ( pDup == null )
return;
if ( pEList.a[iCol].iAlias == 0 )
{
pEList.a[iCol].iAlias = (u16)( ++pParse.nAlias );
}
pDup.iTable = pEList.a[iCol].iAlias;
}
else if ( ExprHasProperty( pOrig, EP_IntValue ) || pOrig.u.zToken == null )
{
pDup = sqlite3ExprDup( db, pOrig, 0 );
if ( pDup == null )
return;
}
else
{
string zToken = pOrig.u.zToken;
Debug.Assert( zToken != null );
pOrig.u.zToken = null;
pDup = sqlite3ExprDup( db, pOrig, 0 );
pOrig.u.zToken = zToken;
if ( pDup == null )
return;
Debug.Assert( ( pDup.flags & ( EP_Reduced | EP_TokenOnly ) ) == 0 );
pDup.flags2 |= EP2_MallocedToken;
pDup.u.zToken = zToken;// sqlite3DbStrDup( db, zToken );
}
if ( ( pExpr.flags & EP_ExpCollate ) != 0 )
{
pDup.pColl = pExpr.pColl;
pDup.flags |= EP_ExpCollate;
}
/* Before calling sqlite3ExprDelete(), set the EP_Static flag. This
** prevents ExprDelete() from deleting the Expr structure itself,
** allowing it to be repopulated by the memcpy() on the following line.
*/
ExprSetProperty( pExpr, EP_Static );
sqlite3ExprDelete( db, ref pExpr );
pExpr.CopyFrom( pDup ); //memcpy(pExpr, pDup, sizeof(*pExpr));
sqlite3DbFree( db, ref pDup );
}
/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr
** expression node refer back to that source column. The following changes
** are made to pExpr:
**
** pExpr->iDb Set the index in db->aDb[] of the database X
** (even if X is implied).
** pExpr->iTable Set to the cursor number for the table obtained
** from pSrcList.
** pExpr->pTab Points to the Table structure of X.Y (even if
** X and/or Y are implied.)
** pExpr->iColumn Set to the column number within the table.
** pExpr->op Set to TK_COLUMN.
** pExpr->pLeft Any expression this points to is deleted
** pExpr->pRight Any expression this points to is deleted.
**
** The zDb variable is the name of the database (the "X"). This value may be
** NULL meaning that name is of the form Y.Z or Z. Any available database
** can be used. The zTable variable is the name of the table (the "Y"). This
** value can be NULL if zDb is also NULL. If zTable is NULL it
** means that the form of the name is Z and that columns from any table
** can be used.
**
** If the name cannot be resolved unambiguously, leave an error message
** in pParse and return WRC_Abort. Return WRC_Prune on success.
*/
static int lookupName(
Parse pParse, /* The parsing context */
string zDb, /* Name of the database containing table, or NULL */
string zTab, /* Name of table containing column, or NULL */
string zCol, /* Name of the column. */
NameContext pNC, /* The name context used to resolve the name */
Expr pExpr /* Make this EXPR node point to the selected column */
)
{
int i, j; /* Loop counters */
int cnt = 0; /* Number of matching column names */
int cntTab = 0; /* Number of matching table names */
sqlite3 db = pParse.db; /* The database connection */
SrcList_item pItem; /* Use for looping over pSrcList items */
SrcList_item pMatch = null; /* The matching pSrcList item */
NameContext pTopNC = pNC; /* First namecontext in the list */
Schema pSchema = null; /* Schema of the expression */
int isTrigger = 0;
Debug.Assert( pNC != null ); /* the name context cannot be NULL. */
Debug.Assert( zCol != null ); /* The Z in X.Y.Z cannot be NULL */
Debug.Assert( !ExprHasAnyProperty( pExpr, EP_TokenOnly | EP_Reduced ) );
/* Initialize the node to no-match */
pExpr.iTable = -1;
pExpr.pTab = null;
ExprSetIrreducible( pExpr );
/* Start at the inner-most context and move outward until a match is found */
while ( pNC != null && cnt == 0 )
{
ExprList pEList;
SrcList pSrcList = pNC.pSrcList;
if ( pSrcList != null )
{
for ( i = 0; i < pSrcList.nSrc; i++ )//, pItem++ )
{
pItem = pSrcList.a[i];
Table pTab;
int iDb;
Column pCol;
pTab = pItem.pTab;
Debug.Assert( pTab != null && pTab.zName != null );
iDb = sqlite3SchemaToIndex( db, pTab.pSchema );
Debug.Assert( pTab.nCol > 0 );
if ( zTab != null )
{
if ( pItem.zAlias != null )
{
string zTabName = pItem.zAlias;
if ( !zTabName.Equals( zTab, StringComparison.OrdinalIgnoreCase ) )
continue;
}
else
{
string zTabName = pTab.zName;
if ( NEVER( zTabName == null ) || !zTabName.Equals( zTab ,StringComparison.OrdinalIgnoreCase ) )
{
continue;
}
if ( zDb != null && !db.aDb[iDb].zName.Equals( zDb ,StringComparison.OrdinalIgnoreCase ) )
{
continue;
}
}
}
if ( 0 == ( cntTab++ ) )
{
pExpr.iTable = pItem.iCursor;
pExpr.pTab = pTab;
pSchema = pTab.pSchema;
pMatch = pItem;
}
for ( j = 0; j < pTab.nCol; j++ )//, pCol++ )
{
pCol = pTab.aCol[j];
if ( pCol.zName.Equals( zCol, StringComparison.OrdinalIgnoreCase ) )
{
IdList pUsing;
cnt++;
pExpr.iTable = pItem.iCursor;
pExpr.pTab = pTab;
pMatch = pItem;
pSchema = pTab.pSchema;
/* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
pExpr.iColumn = (short)( j == pTab.iPKey ? -1 : j );
if ( i < pSrcList.nSrc - 1 )
{
if ( ( pSrcList.a[i + 1].jointype & JT_NATURAL ) != 0 )// pItem[1].jointype
{
/* If this match occurred in the left table of a natural join,
** then skip the right table to avoid a duplicate match */
//pItem++;
i++;
}
else if ( ( pUsing = pSrcList.a[i + 1].pUsing ) != null )//pItem[1].pUsing
{
/* If this match occurs on a column that is in the USING clause
** of a join, skip the search of the right table of the join
** to avoid a duplicate match there. */
int k;
for ( k = 0; k < pUsing.nId; k++ )
{
if ( pUsing.a[k].zName.Equals( zCol ,StringComparison.OrdinalIgnoreCase ) )
{
//pItem++;
i++;
break;
}
}
}
}
break;
}
}
}
}
#if !SQLITE_OMIT_TRIGGER
/* If we have not already resolved the name, then maybe
** it is a new.* or old.* trigger argument reference
*/
if ( zDb == null && zTab != null && cnt == 0 && pParse.pTriggerTab != null )
{
int op = pParse.eTriggerOp;
Table pTab = null;
Debug.Assert( op == TK_DELETE || op == TK_UPDATE || op == TK_INSERT );
if ( op != TK_DELETE && "new".Equals( zTab ,StringComparison.OrdinalIgnoreCase ) )
{
pExpr.iTable = 1;
pTab = pParse.pTriggerTab;
}
else if ( op != TK_INSERT && "old".Equals( zTab ,StringComparison.OrdinalIgnoreCase ) )
{
pExpr.iTable = 0;
pTab = pParse.pTriggerTab;
}
if ( pTab != null )
{
int iCol;
pSchema = pTab.pSchema;
cntTab++;
for ( iCol = 0; iCol < pTab.nCol; iCol++ )
{
Column pCol = pTab.aCol[iCol];
if ( pCol.zName.Equals( zCol ,StringComparison.OrdinalIgnoreCase ) )
{
if ( iCol == pTab.iPKey )
{
iCol = -1;
}
break;
}
}
if ( iCol >= pTab.nCol && sqlite3IsRowid( zCol ) )
{
iCol = -1; /* IMP: R-44911-55124 */
}
if ( iCol < pTab.nCol )
{
cnt++;
if ( iCol < 0 )
{
pExpr.affinity = SQLITE_AFF_INTEGER;
}
else if ( pExpr.iTable == 0 )
{
testcase( iCol == 31 );
testcase( iCol == 32 );
pParse.oldmask |= ( iCol >= 32 ? 0xffffffff : ( ( (u32)1 ) << iCol ) );
}
else
{
testcase( iCol == 31 );
testcase( iCol == 32 );
pParse.newmask |= ( iCol >= 32 ? 0xffffffff : ( ( (u32)1 ) << iCol ) );
}
pExpr.iColumn = (i16)iCol;
pExpr.pTab = pTab;
isTrigger = 1;
}
}
}
#endif //* !SQLITE_OMIT_TRIGGER) */
/*
** Perhaps the name is a reference to the ROWID
*/
if ( cnt == 0 && cntTab == 1 && sqlite3IsRowid( zCol ) )
{
cnt = 1;
pExpr.iColumn = -1; /* IMP: R-44911-55124 */
pExpr.affinity = SQLITE_AFF_INTEGER;
}
/*
** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
** might refer to an result-set alias. This happens, for example, when
** we are resolving names in the WHERE clause of the following command:
**
** SELECT a+b AS x FROM table WHERE x<10;
**
** In cases like this, replace pExpr with a copy of the expression that
** forms the result set entry ("a+b" in the example) and return immediately.
** Note that the expression in the result set should have already been
** resolved by the time the WHERE clause is resolved.
*/
if ( cnt == 0 && ( pEList = pNC.pEList ) != null && zTab == null )
{
for ( j = 0; j < pEList.nExpr; j++ )
{
string zAs = pEList.a[j].zName;
if ( zAs != null && zAs.Equals( zCol ,StringComparison.OrdinalIgnoreCase ) )
{
Expr pOrig;
Debug.Assert( pExpr.pLeft == null && pExpr.pRight == null );
Debug.Assert( pExpr.x.pList == null );
Debug.Assert( pExpr.x.pSelect == null );
pOrig = pEList.a[j].pExpr;
if ( 0 == pNC.allowAgg && ExprHasProperty( pOrig, EP_Agg ) )
{
sqlite3ErrorMsg( pParse, "misuse of aliased aggregate %s", zAs );
return WRC_Abort;
}
resolveAlias( pParse, pEList, j, pExpr, string.Empty );
cnt = 1;
pMatch = null;
Debug.Assert( zTab == null && zDb == null );
goto lookupname_end;
}
}
}
/* Advance to the next name context. The loop will exit when either
** we have a match (cnt>0) or when we run out of name contexts.
*/
if ( cnt == 0 )
{
pNC = pNC.pNext;
}
}
/*
** If X and Y are NULL (in other words if only the column name Z is
** supplied) and the value of Z is enclosed in double-quotes, then
** Z is a string literal if it doesn't match any column names. In that
** case, we need to return right away and not make any changes to
** pExpr.
**
** Because no reference was made to outer contexts, the pNC.nRef
** fields are not changed in any context.
*/
if ( cnt == 0 && zTab == null && ExprHasProperty( pExpr, EP_DblQuoted ) )
{
pExpr.op = TK_STRING;
pExpr.pTab = null;
return WRC_Prune;
}
/*
** cnt==0 means there was not match. cnt>1 means there were two or
** more matches. Either way, we have an error.
*/
if ( cnt != 1 )
{
string zErr;
zErr = cnt == 0 ? "no such column" : "ambiguous column name";
if ( zDb != null )
{
sqlite3ErrorMsg( pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol );
}
else if ( zTab != null )
{
sqlite3ErrorMsg( pParse, "%s: %s.%s", zErr, zTab, zCol );
}
else
{
sqlite3ErrorMsg( pParse, "%s: %s", zErr, zCol );
}
pParse.checkSchema = 1;
pTopNC.nErr++;
}
/* If a column from a table in pSrcList is referenced, then record
** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes
** bit 0 to be set. Column 1 sets bit 1. And so forth. If the
** column number is greater than the number of bits in the bitmask
** then set the high-order bit of the bitmask.
*/
if ( pExpr.iColumn >= 0 && pMatch != null )
{
int n = pExpr.iColumn;
testcase( n == BMS - 1 );
if ( n >= BMS )
{
n = BMS - 1;
}
Debug.Assert( pMatch.iCursor == pExpr.iTable );
pMatch.colUsed |= ( (Bitmask)1 ) << n;
}
/* Clean up and return
*/
sqlite3ExprDelete( db, ref pExpr.pLeft );
pExpr.pLeft = null;
sqlite3ExprDelete( db, ref pExpr.pRight );
pExpr.pRight = null;
pExpr.op = (u8)( isTrigger != 0 ? TK_TRIGGER : TK_COLUMN );
lookupname_end:
if ( cnt == 1 )
{
Debug.Assert( pNC != null );
sqlite3AuthRead( pParse, pExpr, pSchema, pNC.pSrcList );
/* Increment the nRef value on all name contexts from TopNC up to
** the point where the name matched. */
for ( ; ; )
{
Debug.Assert( pTopNC != null );
pTopNC.nRef++;
if ( pTopNC == pNC )
break;
pTopNC = pTopNC.pNext;
}
return WRC_Prune;
}
else
{
return WRC_Abort;
}
}
/*
** Allocate and return a pointer to an expression to load the column iCol
** from datasource iSrc in SrcList pSrc.
*/
static Expr sqlite3CreateColumnExpr( sqlite3 db, SrcList pSrc, int iSrc, int iCol )
{
Expr p = sqlite3ExprAlloc( db, TK_COLUMN, null, 0 );
if ( p != null )
{
SrcList_item pItem = pSrc.a[iSrc];
p.pTab = pItem.pTab;
p.iTable = pItem.iCursor;
if ( p.pTab.iPKey == iCol )
{
p.iColumn = -1;
}
else
{
p.iColumn = (ynVar)iCol;
testcase( iCol == BMS );
testcase( iCol == BMS - 1 );
pItem.colUsed |= ( (Bitmask)1 ) << ( iCol >= BMS ? BMS - 1 : iCol );
}
ExprSetProperty( p, EP_Resolved );
}
return p;
}
/*
** This routine is callback for sqlite3WalkExpr().
**
** Resolve symbolic names into TK_COLUMN operators for the current
** node in the expression tree. Return 0 to continue the search down
** the tree or 2 to abort the tree walk.
**
** This routine also does error checking and name resolution for
** function names. The operator for aggregate functions is changed
** to TK_AGG_FUNCTION.
*/
static int resolveExprStep( Walker pWalker, ref Expr pExpr )
{
NameContext pNC;
Parse pParse;
pNC = pWalker.u.pNC;
Debug.Assert( pNC != null );
pParse = pNC.pParse;
Debug.Assert( pParse == pWalker.pParse );
if ( ExprHasAnyProperty( pExpr, EP_Resolved ) )
return WRC_Prune;
ExprSetProperty( pExpr, EP_Resolved );
#if !NDEBUG
if ( pNC.pSrcList != null && pNC.pSrcList.nAlloc > 0 )
{
SrcList pSrcList = pNC.pSrcList;
int i;
for ( i = 0; i < pNC.pSrcList.nSrc; i++ )
{
Debug.Assert( pSrcList.a[i].iCursor >= 0 && pSrcList.a[i].iCursor < pParse.nTab );
}
}
#endif
switch ( pExpr.op )
{
#if (SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !(SQLITE_OMIT_SUBQUERY)
/* The special operator TK_ROW means use the rowid for the first
** column in the FROM clause. This is used by the LIMIT and ORDER BY
** clause processing on UPDATE and DELETE statements.
*/
case TK_ROW: {
SrcList pSrcList = pNC.pSrcList;
SrcList_item pItem;
Debug.Assert( pSrcList !=null && pSrcList.nSrc==1 );
pItem = pSrcList.a[0];
pExpr.op = TK_COLUMN;
pExpr.pTab = pItem.pTab;
pExpr.iTable = pItem.iCursor;
pExpr.iColumn = -1;
pExpr.affinity = SQLITE_AFF_INTEGER;
break;
}
#endif //* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) /
/* A lone identifier is the name of a column.
*/
case TK_ID:
{
return lookupName( pParse, null, null, pExpr.u.zToken, pNC, pExpr );
}
/* A table name and column name: ID.ID
** Or a database, table and column: ID.ID.ID
*/
case TK_DOT:
{
string zColumn;
string zTable;
string zDb;
Expr pRight;
/* if( pSrcList==0 ) break; */
pRight = pExpr.pRight;
if ( pRight.op == TK_ID )
{
zDb = null;
zTable = pExpr.pLeft.u.zToken;
zColumn = pRight.u.zToken;
}
else
{
Debug.Assert( pRight.op == TK_DOT );
zDb = pExpr.pLeft.u.zToken;
zTable = pRight.pLeft.u.zToken;
zColumn = pRight.pRight.u.zToken;
}
return lookupName( pParse, zDb, zTable, zColumn, pNC, pExpr );
}
/* Resolve function names
*/
case TK_CONST_FUNC:
case TK_FUNCTION:
{
ExprList pList = pExpr.x.pList; /* The argument list */
int n = pList != null ? pList.nExpr : 0; /* Number of arguments */
bool no_such_func = false; /* True if no such function exists */
bool wrong_num_args = false; /* True if wrong number of arguments */
bool is_agg = false; /* True if is an aggregate function */
int auth; /* Authorization to use the function */
int nId; /* Number of characters in function name */
string zId; /* The function name. */
FuncDef pDef; /* Information about the function */
u8 enc = (u8)pParse.db.aDbStatic[0].pSchema.enc;// ENC( pParse.db ); /* The database encoding */
testcase( pExpr.op == TK_CONST_FUNC );
Debug.Assert( !ExprHasProperty( pExpr, EP_xIsSelect ) );
zId = pExpr.u.zToken;
nId = sqlite3Strlen30( zId );
pDef = sqlite3FindFunction( pParse.db, zId, nId, n, enc, 0 );
if ( pDef == null )
{
pDef = sqlite3FindFunction( pParse.db, zId, nId, -1, enc, 0 );
if ( pDef == null )
{
no_such_func = true;
}
else
{
wrong_num_args = true;
}
}
else
{
is_agg = pDef.xFunc == null;
}
#if !SQLITE_OMIT_AUTHORIZATION
if( pDef ){
auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef.zName, 0);
if( auth!=SQLITE_OK ){
if( auth==SQLITE_DENY ){
sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
pDef.zName);
pNC.nErr++;
}
pExpr.op = TK_NULL;
return WRC_Prune;
}
}
#endif
if ( is_agg && 0 == pNC.allowAgg )
{
sqlite3ErrorMsg( pParse, "misuse of aggregate function %.*s()", nId, zId );
pNC.nErr++;
is_agg = false;
}
else if ( no_such_func )
{
sqlite3ErrorMsg( pParse, "no such function: %.*s", nId, zId );
pNC.nErr++;
}
else if ( wrong_num_args )
{
sqlite3ErrorMsg( pParse, "wrong number of arguments to function %.*s()",
nId, zId );
pNC.nErr++;
}
if ( is_agg )
{
pExpr.op = TK_AGG_FUNCTION;
pNC.hasAgg = 1;
}
if ( is_agg )
pNC.allowAgg = 0;
sqlite3WalkExprList( pWalker, pList );
if ( is_agg )
pNC.allowAgg = 1;
/* FIX ME: Compute pExpr.affinity based on the expected return
** type of the function
*/
return WRC_Prune;
}
#if !SQLITE_OMIT_SUBQUERY
case TK_SELECT:
case TK_EXISTS:
{
testcase( pExpr.op == TK_EXISTS );
goto case TK_IN;
}
#endif
case TK_IN:
{
testcase( pExpr.op == TK_IN );
if ( ExprHasProperty( pExpr, EP_xIsSelect ) )
{
int nRef = pNC.nRef;
#if !SQLITE_OMIT_CHECK
if ( pNC.isCheck != 0 )
{
sqlite3ErrorMsg( pParse, "subqueries prohibited in CHECK constraints" );
}
#endif
sqlite3WalkSelect( pWalker, pExpr.x.pSelect );
Debug.Assert( pNC.nRef >= nRef );
if ( nRef != pNC.nRef )
{
ExprSetProperty( pExpr, EP_VarSelect );
}
}
break;
}
#if !SQLITE_OMIT_CHECK
case TK_VARIABLE:
{
if ( pNC.isCheck != 0 )
{
sqlite3ErrorMsg( pParse, "parameters prohibited in CHECK constraints" );
}
break;
}
#endif
}
return ( pParse.nErr != 0 /* || pParse.db.mallocFailed != 0 */ ) ? WRC_Abort : WRC_Continue;
}
/*
** pEList is a list of expressions which are really the result set of the
** a SELECT statement. pE is a term in an ORDER BY or GROUP BY clause.
** This routine checks to see if pE is a simple identifier which corresponds
** to the AS-name of one of the terms of the expression list. If it is,
** this routine return an integer between 1 and N where N is the number of
** elements in pEList, corresponding to the matching entry. If there is
** no match, or if pE is not a simple identifier, then this routine
** return 0.
**
** pEList has been resolved. pE has not.
*/
static int resolveAsName(
Parse pParse, /* Parsing context for error messages */
ExprList pEList, /* List of expressions to scan */
Expr pE /* Expression we are trying to match */
)
{
int i; /* Loop counter */
UNUSED_PARAMETER( pParse );
if ( pE.op == TK_ID )
{
string zCol = pE.u.zToken;
for ( i = 0; i < pEList.nExpr; i++ )
{
string zAs = pEList.a[i].zName;
if ( zAs != null && zAs.Equals( zCol ,StringComparison.OrdinalIgnoreCase ) )
{
return i + 1;
}
}
}
return 0;
}
/*
** pE is a pointer to an expression which is a single term in the
** ORDER BY of a compound SELECT. The expression has not been
** name resolved.
**
** At the point this routine is called, we already know that the
** ORDER BY term is not an integer index into the result set. That
** case is handled by the calling routine.
**
** Attempt to match pE against result set columns in the left-most
** SELECT statement. Return the index i of the matching column,
** as an indication to the caller that it should sort by the i-th column.
** The left-most column is 1. In other words, the value returned is the
** same integer value that would be used in the SQL statement to indicate
** the column.
**
** If there is no match, return 0. Return -1 if an error occurs.
*/
static int resolveOrderByTermToExprList(
Parse pParse, /* Parsing context for error messages */
Select pSelect, /* The SELECT statement with the ORDER BY clause */
Expr pE /* The specific ORDER BY term */
)
{
int i = 0; /* Loop counter */
ExprList pEList; /* The columns of the result set */
NameContext nc; /* Name context for resolving pE */
sqlite3 db; /* Database connection */
int rc; /* Return code from subprocedures */
u8 savedSuppErr; /* Saved value of db->suppressErr */
Debug.Assert( sqlite3ExprIsInteger( pE, ref i ) == 0 );
pEList = pSelect.pEList;
/* Resolve all names in the ORDER BY term expression
*/
nc = new NameContext();// memset( &nc, 0, sizeof( nc ) );
nc.pParse = pParse;
nc.pSrcList = pSelect.pSrc;
nc.pEList = pEList;
nc.allowAgg = 1;
nc.nErr = 0;
db = pParse.db;
savedSuppErr = db.suppressErr;
db.suppressErr = 1;
rc = sqlite3ResolveExprNames( nc, ref pE );
db.suppressErr = savedSuppErr;
if ( rc != 0 )
return 0;
/* Try to match the ORDER BY expression against an expression
** in the result set. Return an 1-based index of the matching
** result-set entry.
*/
for ( i = 0; i < pEList.nExpr; i++ )
{
if ( sqlite3ExprCompare( pEList.a[i].pExpr, pE ) < 2 )
{
return i + 1;
}
}
/* If no match, return 0. */
return 0;
}
/*
** Generate an ORDER BY or GROUP BY term out-of-range error.
*/
static void resolveOutOfRangeError(
Parse pParse, /* The error context into which to write the error */
string zType, /* "ORDER" or "GROUP" */
int i, /* The index (1-based) of the term out of range */
int mx /* Largest permissible value of i */
)
{
sqlite3ErrorMsg( pParse,
"%r %s BY term out of range - should be " +
"between 1 and %d", i, zType, mx );
}
/*
** Analyze the ORDER BY clause in a compound SELECT statement. Modify
** each term of the ORDER BY clause is a constant integer between 1
** and N where N is the number of columns in the compound SELECT.
**
** ORDER BY terms that are already an integer between 1 and N are
** unmodified. ORDER BY terms that are integers outside the range of
** 1 through N generate an error. ORDER BY terms that are expressions
** are matched against result set expressions of compound SELECT
** beginning with the left-most SELECT and working toward the right.
** At the first match, the ORDER BY expression is transformed into
** the integer column number.
**
** Return the number of errors seen.
*/
static int resolveCompoundOrderBy(
Parse pParse, /* Parsing context. Leave error messages here */
Select pSelect /* The SELECT statement containing the ORDER BY */
)
{
int i;
ExprList pOrderBy;
ExprList pEList;
sqlite3 db;
int moreToDo = 1;
pOrderBy = pSelect.pOrderBy;
if ( pOrderBy == null )
return 0;
db = pParse.db;
//#if SQLITE_MAX_COLUMN
if ( pOrderBy.nExpr > db.aLimit[SQLITE_LIMIT_COLUMN] )
{
sqlite3ErrorMsg( pParse, "too many terms in ORDER BY clause" );
return 1;
}
//#endif
for ( i = 0; i < pOrderBy.nExpr; i++ )
{
pOrderBy.a[i].done = 0;
}
pSelect.pNext = null;
while ( pSelect.pPrior != null )
{
pSelect.pPrior.pNext = pSelect;
pSelect = pSelect.pPrior;
}
while ( pSelect != null && moreToDo != 0 )
{
ExprList_item pItem;
moreToDo = 0;
pEList = pSelect.pEList;
Debug.Assert( pEList != null );
for ( i = 0; i < pOrderBy.nExpr; i++ )//, pItem++)
{
pItem = pOrderBy.a[i];
int iCol = -1;
Expr pE, pDup;
if ( pItem.done != 0 )
continue;
pE = pItem.pExpr;
if ( sqlite3ExprIsInteger( pE, ref iCol ) != 0 )
{
if ( iCol <= 0 || iCol > pEList.nExpr )
{
resolveOutOfRangeError( pParse, "ORDER", i + 1, pEList.nExpr );
return 1;
}
}
else
{
iCol = resolveAsName( pParse, pEList, pE );
if ( iCol == 0 )
{
pDup = sqlite3ExprDup( db, pE, 0 );
////if ( 0 == db.mallocFailed )
{
Debug.Assert( pDup != null );
iCol = resolveOrderByTermToExprList( pParse, pSelect, pDup );
}
sqlite3ExprDelete( db, ref pDup );
}
}
if ( iCol > 0 )
{
CollSeq pColl = pE.pColl;
int flags = pE.flags & EP_ExpCollate;
sqlite3ExprDelete( db, ref pE );
pItem.pExpr = pE = sqlite3Expr( db, TK_INTEGER, null );
if ( pE == null )
return 1;
pE.pColl = pColl;
pE.flags = (u16)( pE.flags | EP_IntValue | flags );
pE.u.iValue = iCol;
pItem.iCol = (u16)iCol;
pItem.done = 1;
}
else
{
moreToDo = 1;
}
}
pSelect = pSelect.pNext;
}
for ( i = 0; i < pOrderBy.nExpr; i++ )
{
if ( pOrderBy.a[i].done == 0 )
{
sqlite3ErrorMsg( pParse, "%r ORDER BY term does not match any " +
"column in the result set", i + 1 );
return 1;
}
}
return 0;
}
/*
** Check every term in the ORDER BY or GROUP BY clause pOrderBy of
** the SELECT statement pSelect. If any term is reference to a
** result set expression (as determined by the ExprList.a.iCol field)
** then convert that term into a copy of the corresponding result set
** column.
**
** If any errors are detected, add an error message to pParse and
** return non-zero. Return zero if no errors are seen.
*/
static int sqlite3ResolveOrderGroupBy(
Parse pParse, /* Parsing context. Leave error messages here */
Select pSelect, /* The SELECT statement containing the clause */
ExprList pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
string zType /* "ORDER" or "GROUP" */
)
{
int i;
sqlite3 db = pParse.db;
ExprList pEList;
ExprList_item pItem;
if ( pOrderBy == null /* || pParse.db.mallocFailed != 0 */ )
return 0;
//#if SQLITE_MAX_COLUMN
if ( pOrderBy.nExpr > db.aLimit[SQLITE_LIMIT_COLUMN] )
{
sqlite3ErrorMsg( pParse, "too many terms in %s BY clause", zType );
return 1;
}
//#endif
pEList = pSelect.pEList;
Debug.Assert( pEList != null ); /* sqlite3SelectNew() guarantees this */
for ( i = 0; i < pOrderBy.nExpr; i++ )//, pItem++)
{
pItem = pOrderBy.a[i];
if ( pItem.iCol != 0 )
{
if ( pItem.iCol > pEList.nExpr )
{
resolveOutOfRangeError( pParse, zType, i + 1, pEList.nExpr );
return 1;
}
resolveAlias( pParse, pEList, pItem.iCol - 1, pItem.pExpr, zType );
}
}
return 0;
}
/*
** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect.
** The Name context of the SELECT statement is pNC. zType is either
** "ORDER" or "GROUP" depending on which type of clause pOrderBy is.
**
** This routine resolves each term of the clause into an expression.
** If the order-by term is an integer I between 1 and N (where N is the
** number of columns in the result set of the SELECT) then the expression
** in the resolution is a copy of the I-th result-set expression. If
** the order-by term is an identify that corresponds to the AS-name of
** a result-set expression, then the term resolves to a copy of the
** result-set expression. Otherwise, the expression is resolved in
** the usual way - using sqlite3ResolveExprNames().
**
** This routine returns the number of errors. If errors occur, then
** an appropriate error message might be left in pParse. (OOM errors
** excepted.)
*/
static int resolveOrderGroupBy(
NameContext pNC, /* The name context of the SELECT statement */
Select pSelect, /* The SELECT statement holding pOrderBy */
ExprList pOrderBy, /* An ORDER BY or GROUP BY clause to resolve */
string zType /* Either "ORDER" or "GROUP", as appropriate */
)
{
int i; /* Loop counter */
int iCol; /* Column number */
ExprList_item pItem; /* A term of the ORDER BY clause */
Parse pParse; /* Parsing context */
int nResult; /* Number of terms in the result set */
if ( pOrderBy == null )
return 0;
nResult = pSelect.pEList.nExpr;
pParse = pNC.pParse;
for ( i = 0; i < pOrderBy.nExpr; i++ )//, pItem++ )
{
pItem = pOrderBy.a[i];
Expr pE = pItem.pExpr;
iCol = resolveAsName( pParse, pSelect.pEList, pE );
if ( iCol > 0 )
{
/* If an AS-name match is found, mark this ORDER BY column as being
** a copy of the iCol-th result-set column. The subsequent call to
** sqlite3ResolveOrderGroupBy() will convert the expression to a
** copy of the iCol-th result-set expression. */
pItem.iCol = (u16)iCol;
continue;
}
if ( sqlite3ExprIsInteger( pE, ref iCol ) != 0 )
{
/* The ORDER BY term is an integer constant. Again, set the column
** number so that sqlite3ResolveOrderGroupBy() will convert the
** order-by term to a copy of the result-set expression */
if ( iCol < 1 )
{
resolveOutOfRangeError( pParse, zType, i + 1, nResult );
return 1;
}
pItem.iCol = (u16)iCol;
continue;
}
/* Otherwise, treat the ORDER BY term as an ordinary expression */
pItem.iCol = 0;
if ( sqlite3ResolveExprNames( pNC, ref pE ) != 0 )
{
return 1;
}
}
return sqlite3ResolveOrderGroupBy( pParse, pSelect, pOrderBy, zType );
}
/*
** Resolve names in the SELECT statement p and all of its descendents.
*/
static int resolveSelectStep( Walker pWalker, Select p )
{
NameContext pOuterNC; /* Context that contains this SELECT */
NameContext sNC; /* Name context of this SELECT */
bool isCompound; /* True if p is a compound select */
int nCompound; /* Number of compound terms processed so far */
Parse pParse; /* Parsing context */
ExprList pEList; /* Result set expression list */
int i; /* Loop counter */
ExprList pGroupBy; /* The GROUP BY clause */
Select pLeftmost; /* Left-most of SELECT of a compound */
////sqlite3 db; /* Database connection */
Debug.Assert( p != null );
if ( ( p.selFlags & SF_Resolved ) != 0 )
{
return WRC_Prune;
}
pOuterNC = pWalker.u.pNC;
pParse = pWalker.pParse;
////db = pParse.db;
/* Normally sqlite3SelectExpand() will be called first and will have
** already expanded this SELECT. However, if this is a subquery within
** an expression, sqlite3ResolveExprNames() will be called without a
** prior call to sqlite3SelectExpand(). When that happens, let
** sqlite3SelectPrep() do all of the processing for this SELECT.
** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and
** this routine in the correct order.
*/
if ( ( p.selFlags & SF_Expanded ) == 0 )
{
sqlite3SelectPrep( pParse, p, pOuterNC );
return ( pParse.nErr != 0 /*|| db.mallocFailed != 0 */ ) ? WRC_Abort : WRC_Prune;
}
isCompound = p.pPrior != null;
nCompound = 0;
pLeftmost = p;
while ( p != null )
{
Debug.Assert( ( p.selFlags & SF_Expanded ) != 0 );
Debug.Assert( ( p.selFlags & SF_Resolved ) == 0 );
p.selFlags |= SF_Resolved;
/* Resolve the expressions in the LIMIT and OFFSET clauses. These
** are not allowed to refer to any names, so pass an empty NameContext.
*/
sNC = new NameContext();// memset( &sNC, 0, sizeof( sNC ) );
sNC.pParse = pParse;
if ( sqlite3ResolveExprNames( sNC, ref p.pLimit ) != 0 ||
sqlite3ResolveExprNames( sNC, ref p.pOffset ) != 0 )
{
return WRC_Abort;
}
/* Set up the local name-context to pass to sqlite3ResolveExprNames() to
** resolve the result-set expression list.
*/
sNC.allowAgg = 1;
sNC.pSrcList = p.pSrc;
sNC.pNext = pOuterNC;
/* Resolve names in the result set. */
pEList = p.pEList;
Debug.Assert( pEList != null );
for ( i = 0; i < pEList.nExpr; i++ )
{
Expr pX = pEList.a[i].pExpr;
if ( sqlite3ResolveExprNames( sNC, ref pX ) != 0 )
{
return WRC_Abort;
}
}
/* Recursively resolve names in all subqueries
*/
for ( i = 0; i < p.pSrc.nSrc; i++ )
{
SrcList_item pItem = p.pSrc.a[i];
if ( pItem.pSelect != null )
{
string zSavedContext = pParse.zAuthContext;
if ( pItem.zName != null )
pParse.zAuthContext = pItem.zName;
sqlite3ResolveSelectNames( pParse, pItem.pSelect, pOuterNC );
pParse.zAuthContext = zSavedContext;
if ( pParse.nErr != 0 /*|| db.mallocFailed != 0 */ )
return WRC_Abort;
}
}
/* If there are no aggregate functions in the result-set, and no GROUP BY
** expression, do not allow aggregates in any of the other expressions.
*/
Debug.Assert( ( p.selFlags & SF_Aggregate ) == 0 );
pGroupBy = p.pGroupBy;
if ( pGroupBy != null || sNC.hasAgg != 0 )
{
p.selFlags |= SF_Aggregate;
}
else
{
sNC.allowAgg = 0;
}
/* If a HAVING clause is present, then there must be a GROUP BY clause.
*/
if ( p.pHaving != null && pGroupBy == null )
{
sqlite3ErrorMsg( pParse, "a GROUP BY clause is required before HAVING" );
return WRC_Abort;
}
/* Add the expression list to the name-context before parsing the
** other expressions in the SELECT statement. This is so that
** expressions in the WHERE clause (etc.) can refer to expressions by
** aliases in the result set.
**
** Minor point: If this is the case, then the expression will be
** re-evaluated for each reference to it.
*/
sNC.pEList = p.pEList;
if ( sqlite3ResolveExprNames( sNC, ref p.pWhere ) != 0 ||
sqlite3ResolveExprNames( sNC, ref p.pHaving ) != 0
)
{
return WRC_Abort;
}
/* The ORDER BY and GROUP BY clauses may not refer to terms in
** outer queries
*/
sNC.pNext = null;
sNC.allowAgg = 1;
/* Process the ORDER BY clause for singleton SELECT statements.
** The ORDER BY clause for compounds SELECT statements is handled
** below, after all of the result-sets for all of the elements of
** the compound have been resolved.
*/
if ( !isCompound && resolveOrderGroupBy( sNC, p, p.pOrderBy, "ORDER" ) != 0 )
{
return WRC_Abort;
}
//if ( db.mallocFailed != 0 )
//{
// return WRC_Abort;
//}
/* Resolve the GROUP BY clause. At the same time, make sure
** the GROUP BY clause does not contain aggregate functions.
*/
if ( pGroupBy != null )
{
ExprList_item pItem;
if ( resolveOrderGroupBy( sNC, p, pGroupBy, "GROUP" ) != 0 /*|| db.mallocFailed != 0 */ )
{
return WRC_Abort;
}
for ( i = 0; i < pGroupBy.nExpr; i++ )//, pItem++)
{
pItem = pGroupBy.a[i];
if ( ( pItem.pExpr.flags & EP_Agg ) != 0 )//HasProperty(pItem.pExpr, EP_Agg) )
{
sqlite3ErrorMsg( pParse, "aggregate functions are not allowed in " +
"the GROUP BY clause" );
return WRC_Abort;
}
}
}
/* Advance to the next term of the compound
*/
p = p.pPrior;
nCompound++;
}
/* Resolve the ORDER BY on a compound SELECT after all terms of
** the compound have been resolved.
*/
if ( isCompound && resolveCompoundOrderBy( pParse, pLeftmost ) != 0 )
{
return WRC_Abort;
}
return WRC_Prune;
}
/*
** This routine walks an expression tree and resolves references to
** table columns and result-set columns. At the same time, do error
** checking on function usage and set a flag if any aggregate functions
** are seen.
**
** To resolve table columns references we look for nodes (or subtrees) of the
** form X.Y.Z or Y.Z or just Z where
**
** X: The name of a database. Ex: "main" or "temp" or
** the symbolic name assigned to an ATTACH-ed database.
**
** Y: The name of a table in a FROM clause. Or in a trigger
** one of the special names "old" or "new".
**
** Z: The name of a column in table Y.
**
** The node at the root of the subtree is modified as follows:
**
** Expr.op Changed to TK_COLUMN
** Expr.pTab Points to the Table object for X.Y
** Expr.iColumn The column index in X.Y. -1 for the rowid.
** Expr.iTable The VDBE cursor number for X.Y
**
**
** To resolve result-set references, look for expression nodes of the
** form Z (with no X and Y prefix) where the Z matches the right-hand
** size of an AS clause in the result-set of a SELECT. The Z expression
** is replaced by a copy of the left-hand side of the result-set expression.
** Table-name and function resolution occurs on the substituted expression
** tree. For example, in:
**
** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
**
** The "x" term of the order by is replaced by "a+b" to render:
**
** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
**
** Function calls are checked to make sure that the function is
** defined and that the correct number of arguments are specified.
** If the function is an aggregate function, then the pNC.hasAgg is
** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
** If an expression contains aggregate functions then the EP_Agg
** property on the expression is set.
**
** An error message is left in pParse if anything is amiss. The number
** if errors is returned.
*/
static int sqlite3ResolveExprNames(
NameContext pNC, /* Namespace to resolve expressions in. */
ref Expr pExpr /* The expression to be analyzed. */
)
{
u8 savedHasAgg;
Walker w = new Walker();
if ( pExpr == null )
return 0;
#if SQLITE_MAX_EXPR_DEPTH//>0
{
Parse pParse = pNC.pParse;
if( sqlite3ExprCheckHeight(pParse, pExpr.nHeight+pNC.pParse.nHeight) ){
return 1;
}
pParse.nHeight += pExpr.nHeight;
}
#endif
savedHasAgg = pNC.hasAgg;
pNC.hasAgg = 0;
w.xExprCallback = resolveExprStep;
w.xSelectCallback = resolveSelectStep;
w.pParse = pNC.pParse;
w.u.pNC = pNC;
sqlite3WalkExpr( w, ref pExpr );
#if SQLITE_MAX_EXPR_DEPTH//>0
pNC.pParse.nHeight -= pExpr.nHeight;
#endif
if ( pNC.nErr > 0 || w.pParse.nErr > 0 )
{
ExprSetProperty( pExpr, EP_Error );
}
if ( pNC.hasAgg != 0 )
{
ExprSetProperty( pExpr, EP_Agg );
}
else if ( savedHasAgg != 0 )
{
pNC.hasAgg = 1;
}
return ExprHasProperty( pExpr, EP_Error ) ? 1 : 0;
}
/*
** Resolve all names in all expressions of a SELECT and in all
** decendents of the SELECT, including compounds off of p.pPrior,
** subqueries in expressions, and subqueries used as FROM clause
** terms.
**
** See sqlite3ResolveExprNames() for a description of the kinds of
** transformations that occur.
**
** All SELECT statements should have been expanded using
** sqlite3SelectExpand() prior to invoking this routine.
*/
static void sqlite3ResolveSelectNames(
Parse pParse, /* The parser context */
Select p, /* The SELECT statement being coded. */
NameContext pOuterNC /* Name context for parent SELECT statement */
)
{
Walker w = new Walker();
Debug.Assert( p != null );
w.xExprCallback = resolveExprStep;
w.xSelectCallback = resolveSelectStep;
w.pParse = pParse;
w.u.pNC = pOuterNC;
sqlite3WalkSelect( w, p );
}
}
}