Change RTREE so that the sqlite3_blob object is closed whenever the cursor

count drops to zero and there is not a pending write transaction.

FossilOrigin-Name: 9bb4eafe1a60176ed2e731bb7e3067c0b8a46615

ext/rtree/rtree.c

@@ -119,11 +119,13 @@ struct Rtree {
   u8 nDim2;                   /* Twice the number of dimensions */
   u8 eCoordType;              /* RTREE_COORD_REAL32 or RTREE_COORD_INT32 */
   u8 nBytesPerCell;           /* Bytes consumed per cell */
+  u8 inWrTrans;               /* True if inside write transaction */
   int iDepth;                 /* Current depth of the r-tree structure */
   char *zDb;                  /* Name of database containing r-tree table */
   char *zName;                /* Name of r-tree table */ 
-  int nBusy;                  /* Current number of users of this structure */
+  u32 nBusy;                  /* Current number of users of this structure */
   i64 nRowEst;                /* Estimated number of rows in this table */
+  u32 nCursor;                /* Number of open cursors */
 
   /* List of nodes removed during a CondenseTree operation. List is
   ** linked together via the pointer normally used for hash chains -
@@ -622,7 +624,7 @@ static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent){
 ** Clear the Rtree.pNodeBlob object
 */
 static void nodeBlobReset(Rtree *pRtree){
-  if( pRtree->pNodeBlob ){
+  if( pRtree->pNodeBlob && pRtree->inWrTrans==0 && pRtree->nCursor==0 ){
     sqlite3_blob_close(pRtree->pNodeBlob);
     pRtree->pNodeBlob = 0;
   }
@@ -661,7 +663,7 @@ static int nodeAcquire(
     pRtree->pNodeBlob = pBlob;
     if( rc ){
       nodeBlobReset(pRtree);
-      if( rc==SQLITE_NOMEM ) return rc;
+      if( rc==SQLITE_NOMEM ) return SQLITE_NOMEM;
     }
   }
   if( pRtree->pNodeBlob==0 ){
@@ -674,6 +676,9 @@ static int nodeAcquire(
   if( rc ){
     nodeBlobReset(pRtree);
     *ppNode = 0;
+    /* If unable to open an sqlite3_blob on the desired row, that can only
+    ** be because the shadow tables hold erroneous data. */
+    if( rc==SQLITE_ERROR ) rc = SQLITE_CORRUPT_VTAB;
   }else if( pRtree->iNodeSize==sqlite3_blob_bytes(pRtree->pNodeBlob) ){
     pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode)+pRtree->iNodeSize);
     if( !pNode ){
@@ -935,6 +940,8 @@ static void rtreeReference(Rtree *pRtree){
 static void rtreeRelease(Rtree *pRtree){
   pRtree->nBusy--;
   if( pRtree->nBusy==0 ){
+    pRtree->inWrTrans = 0;
+    pRtree->nCursor = 0;
     nodeBlobReset(pRtree);
     sqlite3_finalize(pRtree->pReadNode);
     sqlite3_finalize(pRtree->pWriteNode);
@@ -990,6 +997,7 @@ static int rtreeDestroy(sqlite3_vtab *pVtab){
 */
 static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
   int rc = SQLITE_NOMEM;
+  Rtree *pRtree = (Rtree *)pVTab;
   RtreeCursor *pCsr;
 
   pCsr = (RtreeCursor *)sqlite3_malloc(sizeof(RtreeCursor));
@@ -997,6 +1005,7 @@ static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
     memset(pCsr, 0, sizeof(RtreeCursor));
     pCsr->base.pVtab = pVTab;
     rc = SQLITE_OK;
+    pRtree->nCursor++;
   }
   *ppCursor = (sqlite3_vtab_cursor *)pCsr;
 
@@ -1029,10 +1038,13 @@ static int rtreeClose(sqlite3_vtab_cursor *cur){
   Rtree *pRtree = (Rtree *)(cur->pVtab);
   int ii;
   RtreeCursor *pCsr = (RtreeCursor *)cur;
+  assert( pRtree->nCursor>0 );
   freeCursorConstraints(pCsr);
   sqlite3_free(pCsr->aPoint);
   for(ii=0; ii<RTREE_CACHE_SZ; ii++) nodeRelease(pRtree, pCsr->aNode[ii]);
   sqlite3_free(pCsr);
+  pRtree->nCursor--;
+  nodeBlobReset(pRtree);
   return SQLITE_OK;
 }
 
@@ -3182,12 +3194,11 @@ constraint:
 
 /*
 ** Called when a transaction starts.
-** This is a no-op.  But the Virtual Table mechanism needs a method
-** here or else it will never call the xRollback and xCommit methods,
-** and those methods are necessary for clearing the sqlite3_blob object.
 */
 static int rtreeBeginTransaction(sqlite3_vtab *pVtab){
-  (void)pVtab;
+  Rtree *pRtree = (Rtree *)pVtab;
+  assert( pRtree->inWrTrans==0 );
+  pRtree->inWrTrans++;
   return SQLITE_OK;
 }
 
@@ -3197,6 +3208,7 @@ static int rtreeBeginTransaction(sqlite3_vtab *pVtab){
 */
 static int rtreeEndTransaction(sqlite3_vtab *pVtab){
   Rtree *pRtree = (Rtree *)pVtab;
+  pRtree->inWrTrans = 0;
   nodeBlobReset(pRtree);
   return SQLITE_OK;
 }

ext/rtree/rtreeA.test

@@ -109,7 +109,7 @@ do_corruption_tests rtreeA-1.1 {
 }
 
 do_execsql_test  rtreeA-1.2.0 { DROP TABLE t1_node } {}
-do_corruption_tests rtreeA-1.2 -error "SQL logic error or missing database" {
+do_corruption_tests rtreeA-1.2 -error "database disk image is malformed" {
   1   "SELECT * FROM t1"
   2   "SELECT * FROM t1 WHERE rowid=5"
   3   "INSERT INTO t1 VALUES(1000, 1, 2, 3, 4)"

manifest

@@ -1,5 +1,5 @@
-C Use\sthe\ssqlite3_blob\sinterface\sfor\sreading\svalues\sfrom\sthe\s%_node\sshadow\ntable\sin\sRTREE.\s\sThis\sis\sa\swork\sin\sprogress.\s\sThere\sare\sstill\ssome\sminor\nproblems.
-D 2017-02-02T02:28:45.543
+C Change\sRTREE\sso\sthat\sthe\ssqlite3_blob\sobject\sis\sclosed\swhenever\sthe\scursor\ncount\sdrops\sto\szero\sand\sthere\sis\snot\sa\spending\swrite\stransaction.
+D 2017-02-02T14:40:06.876
 F Makefile.in 5f415e7867296d678fed2e6779aea10c1318b4bc
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc ba953c8921fc7e18333f61898007206de7e23964
@@ -264,7 +264,7 @@ F ext/rbu/sqlite3rbu.c bb0de6cdbdb14a7d55a097238a434b7e99caf318
 F ext/rbu/sqlite3rbu.h 6fb6294c34a9ca93b5894a33bca530c6f08decba
 F ext/rbu/test_rbu.c 5aa22616afac6f71ebd3d9bc9bf1006cfabcca88
 F ext/rtree/README 6315c0d73ebf0ec40dedb5aa0e942bc8b54e3761
-F ext/rtree/rtree.c 73c4308585c47a7500b9e98617e45a62f8564ddb
+F ext/rtree/rtree.c df33d86df608a16516a95c6d184a5ed9988d2bc9
 F ext/rtree/rtree.h 834dbcb82dc85b2481cde6a07cdadfddc99e9b9e
 F ext/rtree/rtree1.test 42dadfc7b44a436cd74a1bebc0b9b689e4eaf7ec
 F ext/rtree/rtree2.test acbb3a4ce0f4fbc2c304d2b4b784cfa161856bba
@@ -275,7 +275,7 @@ F ext/rtree/rtree6.test 773a90db2dce6a8353dd0d5b64bca69b29761196
 F ext/rtree/rtree7.test 1fa710b9e6bf997a0c1a537b81be7bb6fded1971
 F ext/rtree/rtree8.test db79c812f9e4a11f9b1f3f9934007884610a713a
 F ext/rtree/rtree9.test b5eb13849545dfd271a54ff16784cb00d8792aea
-F ext/rtree/rtreeA.test ace05e729a36e342d40cf94e9efc7b4723d9dcdf
+F ext/rtree/rtreeA.test ac8b503931f2f397cc3c3303354e1e085dcadb86
 F ext/rtree/rtreeB.test c85f9ce78766c4e68b8b89fbf2979ee9cfa82b4e
 F ext/rtree/rtreeC.test c0a9c67f2efa98b6fae12acb8a28348d231a481d
 F ext/rtree/rtreeD.test bdfaaf26df8b4eea7364039aca9150bc1e1f8825
@@ -1552,10 +1552,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 01d97e5b6502b1811b52a681f445e1aaae6c0ee6
-R 79c2c34c9473af6d4e0161547969b398
-T *branch * rtree-sqlite3_blob
-T *sym-rtree-sqlite3_blob *
-T -sym-savepoint-rollback *
+P fc4917d730b29b0bf60fea5e0166728635783e9c
+R 0b53bd94b2e2abfad755fb806046ae11
 U drh
-Z fc394298cc4191cf41d9c752fa550c9c
+Z 9c59d9d407f6159f87ae8b113cdc33c2

manifest.uuid

@@ -1 +1 @@
-fc4917d730b29b0bf60fea5e0166728635783e9c
+9bb4eafe1a60176ed2e731bb7e3067c0b8a46615