Add missing header comments for changes related to the experimental sqlite3_blob_reopen() API.

FossilOrigin-Name: d1cc5c93f09c9092ec478c04e8d9a8b1f9c0cb04

manifest

@@ -1,5 +1,5 @@
-C More\scoverage\stests\sfor\sfts3.c.
+C Add\smissing\sheader\scomments\sfor\schanges\srelated\sto\sthe\sexperimental\ssqlite3_blob_reopen()\sAPI.
-D 2010-10-26T07:14:26
+D 2010-10-26T11:56:58
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 2c8cefd962eca0147132c7cf9eaa4bb24c656f3f
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -176,7 +176,7 @@ F src/resolve.c 1c0f32b64f8e3f555fe1f732f9d6f501a7f05706
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c 6a5c72fb0e8dc7f6133f5a9d7a747130ef0a00ea
 F src/shell.c 8517fc1f9c59ae4007e6cc8b9af91ab231ea2056
-F src/sqlite.h.in 460599b35c035deb339d1c9933089ef32187ecc6
+F src/sqlite.h.in 0c3ab42eef59ee80c564be76c700b542ff530758
 F src/sqlite3ext.h c90bd5507099f62043832d73f6425d8d5c5da754
 F src/sqliteInt.h c63b0340dfdfde18ff255ddccf004edd2d073288
 F src/sqliteLimit.h a17dcd3fb775d63b64a43a55c54cb282f9726f44
@@ -231,7 +231,7 @@ F src/vdbe.h 4de0efb4b0fdaaa900cf419b35c458933ef1c6d2
 F src/vdbeInt.h 7f4cf1b2b69bef3a432b1f23dfebef57275436b4
 F src/vdbeapi.c 5368714fa750270cf6430160287c21adff44582d
 F src/vdbeaux.c de0b06b11a25293e820a49159eca9f1c51a64716
-F src/vdbeblob.c e6e485934fcc9201dd1bfd65864be2bb14243b5d
+F src/vdbeblob.c c2ed68a4f8b764bbc88d3cdbb06c7c274833ae74
 F src/vdbemem.c 23723a12cd3ba7ab3099193094cbb2eb78956aa9
 F src/vdbetrace.c 864cef96919323482ebd9986f2132435115e9cc2
 F src/vtab.c b297e8fa656ab5e66244ab15680d68db0adbec30
@@ -877,7 +877,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 918b609290127f54326c638d82837d117398eade
+P 7a2f2864002d4e9a487e2779ae05513880ecb4d1
-R eb8dee96b23ed044e3e188dc32bc02ca
+R 700e55dce71c563fc39a679df209843f
 U dan
-Z 86656592adbe34ecce7b6ce9cf686881
+Z 667f3356e7b88f02a70759616d0ccab9

manifest.uuid

@@ -1 +1 @@
-7a2f2864002d4e9a487e2779ae05513880ecb4d1
+d1cc5c93f09c9092ec478c04e8d9a8b1f9c0cb04

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);
 

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",