--- a/engine/sqlite/src/vdbeblob.cpp Wed May 26 10:44:32 2010 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,340 +0,0 @@
-/*
-** 2007 May 1
-**
-** 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 code used to implement incremental BLOB I/O.
-**
-** $Id: vdbeblob.cpp 1282 2008-11-13 09:31:33Z LarsPson $
-*/
-
-#include "sqliteInt.h"
-#include "vdbeInt.h"
-
-#ifndef SQLITE_OMIT_INCRBLOB
-
-/*
-** Valid sqlite3_blob* handles point to Incrblob structures.
-*/
-typedef struct Incrblob Incrblob;
-struct Incrblob {
- int flags; /* Copy of "flags" passed to sqlite3_blob_open() */
- int nByte; /* Size of open blob, in bytes */
- int iOffset; /* Byte offset of blob in cursor data */
- BtCursor *pCsr; /* Cursor pointing at blob row */
- sqlite3_stmt *pStmt; /* Statement holding cursor open */
- sqlite3 *db; /* The associated database */
-};
-
-/*
-** Open a blob handle.
-*/
-EXPORT_C 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_Callback.
- ** 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_Integer, 0, 0, 0}, /* 2: Database number */
-
- /* One of the following two instructions is replaced by an
- ** OP_Noop before exection.
- */
- {OP_OpenRead, 0, 0, 0}, /* 3: Open cursor 0 for reading */
- {OP_OpenWrite, 0, 0, 0}, /* 4: Open cursor 0 for read/write */
- {OP_SetNumColumns, 0, 0, 0}, /* 5: Num cols for cursor */
-
- {OP_Variable, 1, 0, 0}, /* 6: Push the rowid to the stack */
- {OP_NotExists, 0, 10, 0}, /* 7: Seek the cursor */
- {OP_Column, 0, 0, 0}, /* 8 */
- {OP_Callback, 0, 0, 0}, /* 9 */
- {OP_Close, 0, 0, 0}, /* 10 */
- {OP_Halt, 0, 0, 0}, /* 11 */
- };
-
- Vdbe *v = 0;
- int rc = SQLITE_OK;
- char zErr[128];
-
- zErr[0] = 0;
- sqlite3_mutex_enter(db->mutex);
- do {
- Parse sParse;
- Table *pTab;
-
- memset(&sParse, 0, sizeof(Parse));
- sParse.db = db;
-
- rc = sqlite3SafetyOn(db);
- if( rc!=SQLITE_OK ){
- sqlite3_mutex_leave(db->mutex);
- return rc;
- }
-
- sqlite3BtreeEnterAll(db);
- pTab = sqlite3LocateTable(&sParse, zTable, zDb);
- if( !pTab ){
- if( sParse.zErrMsg ){
- sqlite3_snprintf(sizeof(zErr), zErr, "%s", sParse.zErrMsg);
- }
- sqlite3_free(sParse.zErrMsg);
- rc = SQLITE_ERROR;
- 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 ){
- sqlite3_snprintf(sizeof(zErr), zErr, "no such column: \"%s\"", zColumn);
- rc = SQLITE_ERROR;
- 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 ){
- sqlite3_snprintf(sizeof(zErr), zErr,
- "cannot open indexed column for writing");
- rc = SQLITE_ERROR;
- 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);
-
- /* Configure the OP_Transaction */
- sqlite3VdbeChangeP1(v, 0, iDb);
- sqlite3VdbeChangeP2(v, 0, (flags ? 1 : 0));
-
- /* 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 db number pushed onto the stack */
- sqlite3VdbeChangeP1(v, 2, iDb);
-
- /* Remove either the OP_OpenWrite or OpenRead. Set the P2
- ** parameter of the other to pTab->tnum.
- */
- sqlite3VdbeChangeToNoop(v, (flags ? 3 : 4), 1);
- sqlite3VdbeChangeP2(v, (flags ? 4 : 3), pTab->tnum);
-
- /* Configure the OP_SetNumColumns. 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.
- */
- sqlite3VdbeChangeP2(v, 5, pTab->nCol+1);
- if( !db->mallocFailed ){
- sqlite3VdbeMakeReady(v, 1, 0, 1, 0);
- }
- }
-
- sqlite3BtreeLeaveAll(db);
- rc = sqlite3SafetyOff(db);
- if( 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);
- sqlite3_snprintf(sizeof(zErr), zErr, 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 ){
- sqlite3_snprintf(sizeof(zErr), zErr, "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 ){
- sqlite3_free(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 ){
- sqlite3_snprintf(sizeof(zErr), zErr, "no such rowid: %lld", iRow);
- rc = SQLITE_ERROR;
- }
-
-blob_open_out:
- zErr[sizeof(zErr)-1] = '\0';
- if( rc!=SQLITE_OK || db->mallocFailed ){
- sqlite3_finalize((sqlite3_stmt *)v);
- }
- sqlite3Error(db, rc, (rc==SQLITE_OK?0:zErr));
- rc = sqlite3ApiExit(db, rc);
- sqlite3_mutex_leave(db->mutex);
- return rc;
-}
-
-/*
-** Close a blob handle that was previously created using
-** sqlite3_blob_open().
-*/
-EXPORT_C int sqlite3_blob_close(sqlite3_blob *pBlob){
- Incrblob *p = (Incrblob *)pBlob;
- int rc;
-
- rc = sqlite3_finalize(p->pStmt);
- sqlite3_free(p);
- return rc;
-}
-
-/*
-** Perform a read or write operation on a blob
-*/
-static int blobReadWrite(
- sqlite3_blob *pBlob,
- void *z,
- int n,
- int iOffset,
- int (*xCall)(BtCursor*, u32, u32, void*)
-){
- int rc;
- Incrblob *p = (Incrblob *)pBlob;
- Vdbe *v;
- sqlite3 *db = p->db;
-
- /* Request is out of range. Return a transient error. */
- if( (iOffset+n)>p->nByte ){
- return SQLITE_ERROR;
- }
- sqlite3_mutex_enter(db->mutex);
-
- /* If there is no statement handle, then the blob-handle has
- ** already been invalidated. Return SQLITE_ABORT in this case.
- */
- v = (Vdbe*)p->pStmt;
- if( v==0 ){
- rc = SQLITE_ABORT;
- }else{
- /* Call either BtreeData() or BtreePutData(). If SQLITE_ABORT is
- ** returned, clean-up the statement handle.
- */
- assert( db == v->db );
- sqlite3BtreeEnterCursor(p->pCsr);
- rc = xCall(p->pCsr, iOffset+p->iOffset, n, z);
- sqlite3BtreeLeaveCursor(p->pCsr);
- if( rc==SQLITE_ABORT ){
- sqlite3VdbeFinalize(v);
- p->pStmt = 0;
- }else{
- db->errCode = rc;
- v->rc = rc;
- }
- }
- rc = sqlite3ApiExit(db, rc);
- sqlite3_mutex_leave(db->mutex);
- return rc;
-}
-
-/*
-** Read data from a blob handle.
-*/
-EXPORT_C int sqlite3_blob_read(sqlite3_blob *pBlob, void *z, int n, int iOffset){
- return blobReadWrite(pBlob, z, n, iOffset, sqlite3BtreeData);
-}
-
-/*
-** Write data to a blob handle.
-*/
-EXPORT_C int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int iOffset){
- return blobReadWrite(pBlob, (void *)z, n, iOffset, sqlite3BtreePutData);
-}
-
-/*
-** Query a blob handle for the size of the data.
-**
-** The Incrblob.nByte field is fixed for the lifetime of the Incrblob
-** so no mutex is required for access.
-*/
-EXPORT_C int sqlite3_blob_bytes(sqlite3_blob *pBlob){
- Incrblob *p = (Incrblob *)pBlob;
- return p->nByte;
-}
-
-#endif /* #ifndef SQLITE_OMIT_INCRBLOB */