/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from
** the prior execution is returned.
**
** This routine sets the error code and string returned by
** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
*/
int sqlite3_reset(sqlite3_stmt *pStmt){
int rc;
if( pStmt==0 ){
rc = SQLITE_OK;
}else{
rc = sqlite3VdbeReset((Vdbe*)pStmt);
sqlite3VdbeMakeReady((Vdbe*)pStmt, -1, 0, 0, 0, 0);
}
return rc;
}
/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from
** the prior execution is returned.
**
** This routine sets the error code and string returned by
** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
*/
int sqlite3_reset(sqlite3_stmt *pStmt){
int rc;
if( pStmt==0 ){
rc = SQLITE_OK;
}else{
rc = sqlite3VdbeReset((Vdbe*)pStmt);
sqlite3VdbeMakeReady((Vdbe*)pStmt, -1, 0, 0, 0);
assert( (rc & (sqlite3_db_handle(pStmt)->errMask))==rc );
}
return rc;
}
/*
** Terminate the current execution of an SQL statement and reset it
** back to its starting state so that it can be reused. A success code from
** the prior execution is returned.
**
** This routine sets the error code and string returned by
** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
*/
int sqlite3_reset(sqlite3_stmt *pStmt){
int rc;
if( pStmt==0 ){
rc = SQLITE_OK;
}else{
Vdbe *v = (Vdbe*)pStmt;
sqlite3_mutex_enter(v->db->mutex);
rc = sqlite3VdbeReset(v);
stmtLruAdd(v);
sqlite3VdbeMakeReady(v, -1, 0, 0, 0);
assert( (rc & (v->db->errMask))==rc );
sqlite3_mutex_leave(v->db->mutex);
}
return rc;
}
/*
** Open a blob handle.
*/
int sqlite3_blob_open(
sqlite3* db, /* The database connection */
const char *zDb, /* The attached database containing the blob */
const char *zTable, /* The table containing the blob */
const char *zColumn, /* The column containing the blob */
sqlite_int64 iRow, /* The row containing the glob */
int flags, /* True -> read/write access, false -> read-only */
sqlite3_blob **ppBlob /* Handle for accessing the blob returned here */
){
int nAttempt = 0;
int iCol; /* Index of zColumn in row-record */
/* This VDBE program seeks a btree cursor to the identified
** db/table/row entry. The reason for using a vdbe program instead
** of writing code to use the b-tree layer directly is that the
** vdbe program will take advantage of the various transaction,
** locking and error handling infrastructure built into the vdbe.
**
** After seeking the cursor, the vdbe executes an OP_ResultRow.
** Code external to the Vdbe then "borrows" the b-tree cursor and
** uses it to implement the blob_read(), blob_write() and
** blob_bytes() functions.
**
** The sqlite3_blob_close() function finalizes the vdbe program,
** which closes the b-tree cursor and (possibly) commits the
** transaction.
*/
static const VdbeOpList openBlob[] = {
{OP_Transaction, 0, 0, 0}, /* 0: Start a transaction */
{OP_VerifyCookie, 0, 0, 0}, /* 1: Check the schema cookie */
{OP_TableLock, 0, 0, 0}, /* 2: Acquire a read or write lock */
/* One of the following two instructions is replaced by an OP_Noop. */
{OP_OpenRead, 0, 0, 0}, /* 3: Open cursor 0 for reading */
{OP_OpenWrite, 0, 0, 0}, /* 4: Open cursor 0 for read/write */
{OP_Variable, 1, 1, 1}, /* 5: Push the rowid to the stack */
{OP_NotExists, 0, 9, 1}, /* 6: Seek the cursor */
{OP_Column, 0, 0, 1}, /* 7 */
{OP_ResultRow, 1, 0, 0}, /* 8 */
{OP_Close, 0, 0, 0}, /* 9 */
{OP_Halt, 0, 0, 0}, /* 10 */
};
Vdbe *v = 0;
int rc = SQLITE_OK;
char *zErr = 0;
Table *pTab;
Parse *pParse;
*ppBlob = 0;
sqlite3_mutex_enter(db->mutex);
pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
if( pParse==0 ){
rc = SQLITE_NOMEM;
goto blob_open_out;
}
do {
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(pParse, 0, zTable, zDb);
if( pTab && IsVirtual(pTab) ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
}
#ifndef SQLITE_OMIT_VIEW
if( pTab && pTab->pSelect ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
}
#endif
if( !pTab ){
if( pParse->zErrMsg ){
sqlite3DbFree(db, zErr);
zErr = pParse->zErrMsg;
pParse->zErrMsg = 0;
}
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* Now search pTab for the exact column. */
for(iCol=0; iCol < pTab->nCol; iCol++) {
if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
break;
}
}
if( iCol==pTab->nCol ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* If the value is being opened for writing, check that the
** column is not indexed. It is against the rules to open an
** indexed column for writing.
*/
if( flags ){
Index *pIdx;
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
int j;
for(j=0; j<pIdx->nColumn; j++){
if( pIdx->aiColumn[j]==iCol ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db,
"cannot open indexed column for writing");
rc = SQLITE_ERROR;
(void)sqlite3SafetyOff(db);
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
}
}
}
v = sqlite3VdbeCreate(db);
if( v ){
int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
flags = !!flags; /* flags = (flags ? 1 : 0); */
/* Configure the OP_Transaction */
sqlite3VdbeChangeP1(v, 0, iDb);
sqlite3VdbeChangeP2(v, 0, flags);
/* Configure the OP_VerifyCookie */
sqlite3VdbeChangeP1(v, 1, iDb);
sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
/* Make sure a mutex is held on the table to be accessed */
sqlite3VdbeUsesBtree(v, iDb);
/* Configure the OP_TableLock instruction */
sqlite3VdbeChangeP1(v, 2, iDb);
sqlite3VdbeChangeP2(v, 2, pTab->tnum);
sqlite3VdbeChangeP3(v, 2, flags);
sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
/* Remove either the OP_OpenWrite or OpenRead. Set the P2
** parameter of the other to pTab->tnum. */
sqlite3VdbeChangeToNoop(v, 4 - flags, 1);
sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
sqlite3VdbeChangeP3(v, 3 + flags, iDb);
/* Configure the number of columns. Configure the cursor to
** think that the table has one more column than it really
** does. An OP_Column to retrieve this imaginary column will
** always return an SQL NULL. This is useful because it means
** we can invoke OP_Column to fill in the vdbe cursors type
** and offset cache without causing any IO.
*/
sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
sqlite3VdbeChangeP2(v, 7, pTab->nCol);
if( !db->mallocFailed ){
sqlite3VdbeMakeReady(v, 1, 1, 1, 0);
}
}
sqlite3BtreeLeaveAll(db);
rc = sqlite3SafetyOff(db);
if( NEVER(rc!=SQLITE_OK) || db->mallocFailed ){
goto blob_open_out;
}
sqlite3_bind_int64((sqlite3_stmt *)v, 1, iRow);
rc = sqlite3_step((sqlite3_stmt *)v);
if( rc!=SQLITE_ROW ){
nAttempt++;
rc = sqlite3_finalize((sqlite3_stmt *)v);
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, sqlite3_errmsg(db));
v = 0;
}
} while( nAttempt<5 && rc==SQLITE_SCHEMA );
if( rc==SQLITE_ROW ){
/* The row-record has been opened successfully. Check that the
** column in question contains text or a blob. If it contains
** text, it is up to the caller to get the encoding right.
*/
Incrblob *pBlob;
u32 type = v->apCsr[0]->aType[iCol];
if( type<12 ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "cannot open value of type %s",
type==0?"null": type==7?"real": "integer"
);
rc = SQLITE_ERROR;
goto blob_open_out;
}
pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
if( db->mallocFailed ){
sqlite3DbFree(db, pBlob);
goto blob_open_out;
}
pBlob->flags = flags;
pBlob->pCsr = v->apCsr[0]->pCursor;
sqlite3BtreeEnterCursor(pBlob->pCsr);
sqlite3BtreeCacheOverflow(pBlob->pCsr);
sqlite3BtreeLeaveCursor(pBlob->pCsr);
pBlob->pStmt = (sqlite3_stmt *)v;
pBlob->iOffset = v->apCsr[0]->aOffset[iCol];
pBlob->nByte = sqlite3VdbeSerialTypeLen(type);
pBlob->db = db;
*ppBlob = (sqlite3_blob *)pBlob;
rc = SQLITE_OK;
}else if( rc==SQLITE_OK ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such rowid: %lld", iRow);
rc = SQLITE_ERROR;
}
blob_open_out:
if( v && (rc!=SQLITE_OK || db->mallocFailed) ){
sqlite3VdbeFinalize(v);
}
sqlite3Error(db, rc, zErr);
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
rc = sqlite3ApiExit(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;
}
/*
** Open a blob handle.
*/
int sqlite3_blob_open(
sqlite3* db, /* The database connection */
const char *zDb, /* The attached database containing the blob */
const char *zTable, /* The table containing the blob */
const char *zColumn, /* The column containing the blob */
sqlite_int64 iRow, /* The row containing the glob */
int flags, /* True -> read/write access, false -> read-only */
sqlite3_blob **ppBlob /* Handle for accessing the blob returned here */
){
int nAttempt = 0;
int iCol; /* Index of zColumn in row-record */
/* This VDBE program seeks a btree cursor to the identified
** db/table/row entry. The reason for using a vdbe program instead
** of writing code to use the b-tree layer directly is that the
** vdbe program will take advantage of the various transaction,
** locking and error handling infrastructure built into the vdbe.
**
** After seeking the cursor, the vdbe executes an OP_ResultRow.
** Code external to the Vdbe then "borrows" the b-tree cursor and
** uses it to implement the blob_read(), blob_write() and
** blob_bytes() functions.
**
** The sqlite3_blob_close() function finalizes the vdbe program,
** which closes the b-tree cursor and (possibly) commits the
** transaction.
*/
static const VdbeOpList openBlob[] = {
{OP_Transaction, 0, 0, 0}, /* 0: Start a transaction */
{OP_VerifyCookie, 0, 0, 0}, /* 1: Check the schema cookie */
{OP_TableLock, 0, 0, 0}, /* 2: Acquire a read or write lock */
/* One of the following two instructions is replaced by an OP_Noop. */
{OP_OpenRead, 0, 0, 0}, /* 3: Open cursor 0 for reading */
{OP_OpenWrite, 0, 0, 0}, /* 4: Open cursor 0 for read/write */
{OP_Variable, 1, 1, 1}, /* 5: Push the rowid to the stack */
{OP_NotExists, 0, 10, 1}, /* 6: Seek the cursor */
{OP_Column, 0, 0, 1}, /* 7 */
{OP_ResultRow, 1, 0, 0}, /* 8 */
{OP_Goto, 0, 5, 0}, /* 9 */
{OP_Close, 0, 0, 0}, /* 10 */
{OP_Halt, 0, 0, 0}, /* 11 */
};
int rc = SQLITE_OK;
char *zErr = 0;
Table *pTab;
Parse *pParse = 0;
Incrblob *pBlob = 0;
flags = !!flags; /* flags = (flags ? 1 : 0); */
*ppBlob = 0;
sqlite3_mutex_enter(db->mutex);
pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
if( !pBlob ) goto blob_open_out;
pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
if( !pParse ) goto blob_open_out;
do {
memset(pParse, 0, sizeof(Parse));
pParse->db = db;
sqlite3DbFree(db, zErr);
zErr = 0;
sqlite3BtreeEnterAll(db);
pTab = sqlite3LocateTable(pParse, 0, zTable, zDb);
if( pTab && IsVirtual(pTab) ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open virtual table: %s", zTable);
}
#ifndef SQLITE_OMIT_VIEW
if( pTab && pTab->pSelect ){
pTab = 0;
sqlite3ErrorMsg(pParse, "cannot open view: %s", zTable);
}
#endif
if( !pTab ){
if( pParse->zErrMsg ){
sqlite3DbFree(db, zErr);
zErr = pParse->zErrMsg;
pParse->zErrMsg = 0;
}
rc = SQLITE_ERROR;
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* Now search pTab for the exact column. */
for(iCol=0; iCol<pTab->nCol; iCol++) {
if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
break;
}
}
if( iCol==pTab->nCol ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
rc = SQLITE_ERROR;
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
/* If the value is being opened for writing, check that the
** column is not indexed, and that it is not part of a foreign key.
** It is against the rules to open a column to which either of these
** descriptions applies for writing. */
if( flags ){
const char *zFault = 0;
Index *pIdx;
#ifndef SQLITE_OMIT_FOREIGN_KEY
if( db->flags&SQLITE_ForeignKeys ){
/* Check that the column is not part of an FK child key definition. It
** is not necessary to check if it is part of a parent key, as parent
** key columns must be indexed. The check below will pick up this
** case. */
FKey *pFKey;
for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
int j;
for(j=0; j<pFKey->nCol; j++){
if( pFKey->aCol[j].iFrom==iCol ){
zFault = "foreign key";
}
}
}
}
#endif
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
int j;
for(j=0; j<pIdx->nColumn; j++){
if( pIdx->aiColumn[j]==iCol ){
zFault = "indexed";
}
}
}
if( zFault ){
sqlite3DbFree(db, zErr);
zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
rc = SQLITE_ERROR;
sqlite3BtreeLeaveAll(db);
goto blob_open_out;
}
}
pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(db);
assert( pBlob->pStmt || db->mallocFailed );
if( pBlob->pStmt ){
Vdbe *v = (Vdbe *)pBlob->pStmt;
int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
/* Configure the OP_Transaction */
sqlite3VdbeChangeP1(v, 0, iDb);
sqlite3VdbeChangeP2(v, 0, flags);
/* Configure the OP_VerifyCookie */
sqlite3VdbeChangeP1(v, 1, iDb);
sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
sqlite3VdbeChangeP3(v, 1, pTab->pSchema->iGeneration);
/* Make sure a mutex is held on the table to be accessed */
sqlite3VdbeUsesBtree(v, iDb);
/* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
sqlite3VdbeChangeToNoop(v, 2);
#else
sqlite3VdbeChangeP1(v, 2, iDb);
sqlite3VdbeChangeP2(v, 2, pTab->tnum);
sqlite3VdbeChangeP3(v, 2, flags);
sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
#endif
/* Remove either the OP_OpenWrite or OpenRead. Set the P2
** parameter of the other to pTab->tnum. */
sqlite3VdbeChangeToNoop(v, 4 - flags);
sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
sqlite3VdbeChangeP3(v, 3 + flags, iDb);
/* Configure the number of columns. Configure the cursor to
** think that the table has one more column than it really
** does. An OP_Column to retrieve this imaginary column will
** always return an SQL NULL. This is useful because it means
** we can invoke OP_Column to fill in the vdbe cursors type
** and offset cache without causing any IO.
*/
sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
sqlite3VdbeChangeP2(v, 7, pTab->nCol);
if( !db->mallocFailed ){
pParse->nVar = 1;
pParse->nMem = 1;
pParse->nTab = 1;
sqlite3VdbeMakeReady(v, pParse);
}
}
pBlob->flags = flags;
pBlob->iCol = iCol;
pBlob->db = db;
sqlite3BtreeLeaveAll(db);
if( db->mallocFailed ){
goto blob_open_out;
}
sqlite3_bind_int64(pBlob->pStmt, 1, iRow);
rc = blobSeekToRow(pBlob, iRow, &zErr);
} while( (++nAttempt)<5 && rc==SQLITE_SCHEMA );
blob_open_out:
if( rc==SQLITE_OK && db->mallocFailed==0 ){
*ppBlob = (sqlite3_blob *)pBlob;
}else{
if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
sqlite3DbFree(db, pBlob);
}
sqlite3Error(db, rc, (zErr ? "%s" : 0), zErr);
sqlite3DbFree(db, zErr);
sqlite3StackFree(db, pParse);
rc = sqlite3ApiExit(db, rc);
sqlite3_mutex_leave(db->mutex);
return rc;
}