diff -r 4a65cc85c4f3 -r fbd95db6a4e1 engine/sqlite/src/vdbeblob.cpp --- a/engine/sqlite/src/vdbeblob.cpp Wed Apr 28 13:20:05 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; jnColumn; 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 */