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Avoid allocating large objects on the stack in the incremental BLOB I/O

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interface. (CVS 6703)

FossilOrigin-Name: ea7dfde700fb57ed0ecb5000a55abbf45aa1e09d
This commit is contained in:
drh
2009-06-01 19:53:30 +00:00
parent e7b3470705
commit 6ee700c32c
3 changed files with 40 additions and 28 deletions
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54
src/vdbeblob.c
View File

@@ -12,7 +12,7 @@
**
** This file contains code used to implement incremental BLOB I/O.
**
** $Id: vdbeblob.c,v 1.32 2009/05/09 15:17:47 drh Exp $
** $Id: vdbeblob.c,v 1.33 2009/06/01 19:53:31 drh Exp $
*/
#include "sqliteInt.h"
@@ -83,40 +83,46 @@ int sqlite3_blob_open(
Vdbe *v = 0;
int rc = SQLITE_OK;
char zErr[128];
char *zErr = 0;
Table *pTab;
Parse *pParse;
*ppBlob = 0;
zErr[0] = 0;
sqlite3_mutex_enter(db->mutex);
pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
if( pParse==0 ){
rc = SQLITE_NOMEM;
goto blob_open_out;
}
do {
Parse sParse;
Table *pTab;
memset(&sParse, 0, sizeof(Parse));
sParse.db = db;
memset(pParse, 0, sizeof(Parse));
pParse->db = db;
if( sqlite3SafetyOn(db) ){
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
sqlite3_mutex_leave(db->mutex);
return SQLITE_MISUSE;
}
sqlite3BtreeEnterAll(db);
pTab = sqlite3LocateTable(&sParse, 0, zTable, zDb);
pTab = sqlite3LocateTable(pParse, 0, zTable, zDb);
if( pTab && IsVirtual(pTab) ){
pTab = 0;
sqlite3ErrorMsg(&sParse, "cannot open virtual table: %s", zTable);
sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
}
#ifndef SQLITE_OMIT_VIEW
if( pTab && pTab->pSelect ){
pTab = 0;
sqlite3ErrorMsg(&sParse, "cannot open view: %s", zTable);
sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
}
#endif
if( !pTab ){
if( sParse.zErrMsg ){
sqlite3_snprintf(sizeof(zErr), zErr, "%s", sParse.zErrMsg);
if( pParse->zErrMsg ){
sqlite3DbFree(db, zErr);
zErr = pParse->zErrMsg;
pParse->zErrMsg = 0;
}
sqlite3DbFree(db, sParse.zErrMsg);
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
@@ -130,7 +136,8 @@ int sqlite3_blob_open(
}
}
if( iCol==pTab->nCol ){
sqlite3_snprintf(sizeof(zErr), zErr, "no such column: \"%s\"", zColumn);
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
@@ -147,7 +154,8 @@ int sqlite3_blob_open(
int j;
for(j=0; j<pIdx->nColumn; j++){
if( pIdx->aiColumn[j]==iCol ){
sqlite3_snprintf(sizeof(zErr), zErr,
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db,
"cannot open indexed column for writing");
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
@@ -207,7 +215,8 @@ int sqlite3_blob_open(
if( rc!=SQLITE_ROW ){
nAttempt++;
rc = sqlite3_finalize((sqlite3_stmt *)v);
sqlite3_snprintf(sizeof(zErr), zErr, sqlite3_errmsg(db));
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, sqlite3_errmsg(db));
v = 0;
}
} while( nAttempt<5 && rc==SQLITE_SCHEMA );
@@ -221,7 +230,8 @@ int sqlite3_blob_open(
u32 type = v->apCsr[0]->aType[iCol];
if( type<12 ){
sqlite3_snprintf(sizeof(zErr), zErr, "cannot open value of type %s",
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "cannot open value of type %s",
type==0?"null": type==7?"real": "integer"
);
rc = SQLITE_ERROR;
@@ -244,16 +254,18 @@ int sqlite3_blob_open(
*ppBlob = (sqlite3_blob *)pBlob;
rc = SQLITE_OK;
}else if( rc==SQLITE_OK ){
sqlite3_snprintf(sizeof(zErr), zErr, "no such rowid: %lld", iRow);
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such rowid: %lld", iRow);
rc = SQLITE_ERROR;
}
blob_open_out:
zErr[sizeof(zErr)-1] = '\0';
if( v && (rc!=SQLITE_OK || db->mallocFailed) ){
sqlite3VdbeFinalize(v);
}
sqlite3Error(db, rc, (rc==SQLITE_OK?0:zErr));
sqlite3Error(db, rc, zErr);
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
rc = sqlite3ApiExit(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;