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Reference count Table structures so that they are not deallocated too soon.

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Ticket #1210. (CVS 2498)

FossilOrigin-Name: e73d25c7419d580c47925494621df26d2fb9f27e
This commit is contained in:
drh
2005-06-06 21:19:56 +00:00
parent 473d179d8a
commit ed8a3bb108
9 changed files with 79 additions and 64 deletions
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45
src/select.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.249 2005/06/06 16:34:33 drh Exp $
** $Id: select.c,v 1.250 2005/06/06 21:19:57 drh Exp $
*/
#include "sqliteInt.h"
@@ -872,6 +872,7 @@ Table *sqlite3ResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
if( pTab==0 ){
return 0;
}
pTab->nRef = 1;
pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
pEList = pSelect->pEList;
pTab->nCol = pEList->nExpr;
@@ -1004,6 +1005,7 @@ static int prepSelectStmt(Parse *pParse, Select *p){
pFrom->zAlias =
sqlite3MPrintf("sqlite_subquery_%p_", (void*)pFrom->pSelect);
}
assert( pFrom->pTab==0 );
pFrom->pTab = pTab =
sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
if( pTab==0 ){
@@ -1017,11 +1019,13 @@ static int prepSelectStmt(Parse *pParse, Select *p){
#endif
}else{
/* An ordinary table or view name in the FROM clause */
assert( pFrom->pTab==0 );
pFrom->pTab = pTab =
sqlite3LocateTable(pParse,pFrom->zName,pFrom->zDatabase);
if( pTab==0 ){
return 1;
}
pTab->nRef++;
#ifndef SQLITE_OMIT_VIEW
if( pTab->pSelect ){
/* We reach here if the named table is a really a view */
@@ -1164,40 +1168,6 @@ static int prepSelectStmt(Parse *pParse, Select *p){
return rc;
}
/*
** This routine recursively unlinks the Select.pSrc.a[].pTab pointers
** in a select structure. It just sets the pointers to NULL. This
** routine is recursive in the sense that if the Select.pSrc.a[].pSelect
** pointer is not NULL, this routine is called recursively on that pointer.
**
** This routine is called on the Select structure that defines a
** VIEW in order to undo any bindings to tables. This is necessary
** because those tables might be DROPed by a subsequent SQL command.
** If the bindings are not removed, then the Select.pSrc->a[].pTab field
** will be left pointing to a deallocated Table structure after the
** DROP and a coredump will occur the next time the VIEW is used.
*/
#if 0
void sqlite3SelectUnbind(Select *p){
int i;
SrcList *pSrc = p->pSrc;
struct SrcList_item *pItem;
Table *pTab;
if( p==0 ) return;
for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
if( (pTab = pItem->pTab)!=0 ){
if( pTab->isTransient ){
sqlite3DeleteTable(0, pTab);
}
pItem->pTab = 0;
if( pItem->pSelect ){
sqlite3SelectUnbind(pItem->pSelect);
}
}
}
}
#endif
#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** This routine associates entries in an ORDER BY expression list with
@@ -2048,11 +2018,8 @@ static int flattenSubquery(
{
int nSubSrc = pSubSrc->nSrc;
int jointype = pSubitem->jointype;
Table *pTab = pSubitem->pTab;
if( pTab && pTab->isTransient ){
sqlite3DeleteTable(0, pSubitem->pTab);
}
sqlite3DeleteTable(0, pSubitem->pTab);
sqliteFree(pSubitem->zDatabase);
sqliteFree(pSubitem->zName);
sqliteFree(pSubitem->zAlias);