diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/sqlite.h.in | 20 | ||||
| -rw-r--r-- | src/vdbeblob.c | 25 |
2 files changed, 42 insertions, 3 deletions
diff --git a/src/sqlite.h.in b/src/sqlite.h.in index 5e32c10c7..8ff8ab78f 100644 --- a/src/sqlite.h.in +++ b/src/sqlite.h.in @@ -4791,7 +4791,25 @@ int sqlite3_blob_open( ); /* -** CAPI3REF: Move a BLOB Handle +** CAPI3REF: Move a BLOB Handle to a New Row +** +** This function is used to move an existing blob handle so that it points +** to a different row of the same database table. The new row is identified +** by the rowid value passed as the second argument. Only the row can be +** changed, the database, table and column on which the blob handle is open +** remain the same. Moving an existing blob handle to a new row can be +** faster than closing the existing handle and opening a new one. +** +** The new row must meet the same criteria as for [sqlite3_blob_open()] - +** it must exist and there must be either a blob or text value stored in +** the nominated column. If the new row is not present in the table, or if +** it does not contain a blob or text value, or if another error occurs, an +** SQLite error code is returned and the blob handle is considered aborted. +** All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or +** [sqlite3_blob_reopen()] on an aborted blob handle immediately return +** SQLITE_ABORT. +** +** This function sets the database handle error code and message. */ SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); diff --git a/src/vdbeblob.c b/src/vdbeblob.c index 129aad736..1bfce65a6 100644 --- a/src/vdbeblob.c +++ b/src/vdbeblob.c @@ -33,16 +33,37 @@ struct Incrblob { }; +/* +** This function is used by both blob_open() and blob_reopen(). It seeks +** the b-tree cursor associated with blob handle p to point to row iRow. +** If successful, SQLITE_OK is returned and subsequent calls to +** sqlite3_blob_read() or sqlite3_blob_write() access the specified row. +** +** If an error occurs, or if the specified row does not exist or does not +** contain a value of type TEXT or BLOB in the column nominated when the +** blob handle was opened, then an error code is returned and *pzErr may +** be set to point to a buffer containing an error message. It is the +** responsibility of the caller to free the error message buffer using +** sqlite3DbFree(). +** +** If an error does occur, then the b-tree cursor is closed. All subsequent +** calls to sqlite3_blob_read(), blob_write() or blob_reopen() will +** immediately return SQLITE_ABORT. +*/ static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){ int rc; /* Error code */ char *zErr = 0; /* Error message */ Vdbe *v = (Vdbe *)p->pStmt; + /* Set the value of the SQL statements only variable to integer iRow. + ** This is done directly instead of using sqlite3_bind_int64() to avoid + ** triggering asserts related to mutexes. + */ + assert( v->aVar[0].flags&MEM_Int ); v->aVar[0].u.i = iRow; - rc = sqlite3_step(p->pStmt); + rc = sqlite3_step(p->pStmt); if( rc==SQLITE_ROW ){ - Vdbe *v = (Vdbe *)p->pStmt; u32 type = v->apCsr[0]->aType[p->iCol]; if( type<12 ){ zErr = sqlite3MPrintf(p->db, "cannot open value of type %s", |