From: drh <drh@noemail.net>
Date: Mon, 22 Jun 2009 19:05:40 +0000 (+0000)
Subject: Simplifications to vdbe.c and it service routines in support of coverage
X-Git-Tag: cvs-to-fossil-cutover~173
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9a65f2cd7d0911fef8a1f5aa1081038454213136;p=thirdparty%2Fsqlite.git

Simplifications to vdbe.c and it service routines in support of coverage
testing. (CVS 6799)

FossilOrigin-Name: 308f2e61520ac7440700d93ca5bab4a844f2dc17
---

diff --git a/manifest b/manifest
index 54380829bf..8bb4405ff7 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Remove\sa\scondition\sthat\sis\salways\strue\sfrom\sbtree.c.\s(CVS\s6798)
-D 2009-06-22T18:03:52
+C Simplifications\sto\svdbe.c\sand\sit\sservice\sroutines\sin\ssupport\sof\scoverage\ntesting.\s(CVS\s6799)
+D 2009-06-22T19:05:41
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -203,13 +203,13 @@ F src/update.c 6ae6c26adff8dc34532d578f66e6cfde04b5d177
 F src/utf.c 9541d28f40441812c0b40f00334372a0542c00ff
 F src/util.c a7e981e032c3c9c0887d50d7e658a33cb355b43d
 F src/vacuum.c 0e14f371ea3326c6b8cfba257286d798cd20db59
-F src/vdbe.c e92e2f4136e33041145a87c056a5d09972add6de
+F src/vdbe.c c5a0a208432e4faf6590201ace57c7c873143089
 F src/vdbe.h 35a648bc3279a120da24f34d9a25213ec15daf8a
 F src/vdbeInt.h 7823eac611229163c6a5df0e9e0d54ffcda527e7
 F src/vdbeapi.c 73bd1d2c57b953bc688d1d8c84b24c2084c2aec7
-F src/vdbeaux.c 516b7e123ece051e93ab1aa96c2ff04578b3b465
+F src/vdbeaux.c 6f0e3680b7b235d7f012de84936f1b7c5320f0c3
 F src/vdbeblob.c c25d7e7bc6d5917feeb17270bd275fa771f26e5c
-F src/vdbemem.c ba39c0afa609595c7c23dfc2ac929d9414faa59f
+F src/vdbemem.c d244e09b5ca8afc3e1cea3ccf0b1a3fa48926614
 F src/vtab.c 98fbffc5efe68d8107511dec0a650efc7daa9446
 F src/walker.c 1edca756275f158b80f20eb6f104c8d3fcc96a04
 F src/where.c cf0d091748c2fa6f7df96e5b08d2db26fd2eb437
@@ -736,7 +736,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P bda38f5e86db45234c2dbb0f8d1a81f6ff6d04e4
-R e49401abe650f38b382c2f4526e14814
-U danielk1977
-Z d013caf2ebacc662cceed0c56ce2e6b5
+P 3ec8b37a89fdb2436d312439715414fae2cd20a8
+R 64e6f4c2a51e80727de7b90d6d047386
+U drh
+Z e09666ff70680840d2021686d00144b7
diff --git a/manifest.uuid b/manifest.uuid
index 4be5ea34e1..3af465c995 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-3ec8b37a89fdb2436d312439715414fae2cd20a8
\ No newline at end of file
+308f2e61520ac7440700d93ca5bab4a844f2dc17
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index 01b5961e29..a594001631 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.860 2009/06/22 12:05:10 drh Exp $
+** $Id: vdbe.c,v 1.861 2009/06/22 19:05:41 drh Exp $
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
@@ -2065,8 +2065,7 @@ case OP_Column: {
       sqlite3BtreeDataSize(pCrsr, &payloadSize);
     }
     nField = pC->nField;
-  }else{
-    assert( pC->pseudoTable );
+  }else if( pC->pseudoTable ){
     /* The record is the sole entry of a pseudo-table */
     payloadSize = pC->nData;
     zRec = pC->pData;
@@ -2074,6 +2073,9 @@ case OP_Column: {
     assert( payloadSize==0 || zRec!=0 );
     nField = pC->nField;
     pCrsr = 0;
+  }else{
+    /* Consider the row to be NULL */
+    payloadSize = 0;
   }
 
   /* If payloadSize is 0, then just store a NULL */
@@ -2939,6 +2941,10 @@ case OP_OpenWrite: {
     pIn2 = &p->aMem[p2];
     sqlite3VdbeMemIntegerify(pIn2);
     p2 = (int)pIn2->u.i;
+    /* The p2 value always comes from a prior OP_CreateTable opcode and
+    ** that opcode will always set the p2 value to 2 or more or else fail.
+    ** If there were a failure, the prepared statement would have halted
+    ** before reaching this instruction. */
     if( NEVER(p2<2) ) {
       rc = SQLITE_CORRUPT_BKPT;
       goto abort_due_to_error;
@@ -3817,8 +3823,17 @@ case OP_Delete: {
     iKey = pC->lastRowid;
   }
 
+  /* The OP_Delete opcode always follows an OP_NotExists or OP_Last or
+  ** OP_Column on the same table without any intervening operations that
+  ** might move or invalidate the cursor.  Hence cursor pC is always pointing
+  ** to the row to be deleted and the sqlite3VdbeCursorMoveto() operation
+  ** below is always a no-op and cannot fail.  We will run it anyhow, though,
+  ** to guard against future changes to the code generator.
+  **/
+  assert( pC->deferredMoveto==0 );
   rc = sqlite3VdbeCursorMoveto(pC);
-  if( rc ) goto abort_due_to_error;
+  if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
+
   sqlite3BtreeSetCachedRowid(pC->pCursor, 0);
   rc = sqlite3BtreeDelete(pC->pCursor);
   pC->cacheStatus = CACHE_STALE;
@@ -3888,8 +3903,16 @@ case OP_RowData: {
   assert( pC->pseudoTable==0 );
   assert( pC->pCursor!=0 );
   pCrsr = pC->pCursor;
+
+  /* The OP_RowKey and OP_RowData opcodes always follow OP_NotExists or
+  ** OP_Rewind/Op_Next with no intervening instructions that might invalidate
+  ** the cursor.  Hence the following sqlite3VdbeCursorMoveto() call is always
+  ** a no-op and can never fail.  But we leave it in place as a safety.
+  */
+  assert( pC->deferredMoveto==0 );
   rc = sqlite3VdbeCursorMoveto(pC);
-  if( rc ) goto abort_due_to_error;
+  if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
+
   if( pC->isIndex ){
     assert( !pC->isTable );
     sqlite3BtreeKeySize(pCrsr, &n64);
@@ -4007,13 +4030,16 @@ case OP_Last: {        /* jump */
   pC = p->apCsr[pOp->p1];
   assert( pC!=0 );
   pCrsr = pC->pCursor;
-  assert( pCrsr!=0 );
-  rc = sqlite3BtreeLast(pCrsr, &res);
+  if( pCrsr==0 ){
+    res = 1;
+  }else{
+    rc = sqlite3BtreeLast(pCrsr, &res);
+  }
   pC->nullRow = (u8)res;
   pC->deferredMoveto = 0;
   pC->rowidIsValid = 0;
   pC->cacheStatus = CACHE_STALE;
-  if( res && pOp->p2>0 ){
+  if( pOp->p2>0 && res ){
     pc = pOp->p2 - 1;
   }
   break;
@@ -4106,7 +4132,10 @@ case OP_Next: {        /* jump */
     break;  /* See ticket #2273 */
   }
   pCrsr = pC->pCursor;
-  assert( pCrsr );
+  if( pCrsr==0 ){
+    pC->nullRow = 1;
+    break;
+  }
   res = 1;
   assert( pC->deferredMoveto==0 );
   rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
@@ -4147,7 +4176,7 @@ case OP_IdxInsert: {        /* in2 */
   assert( pC!=0 );
   assert( pIn2->flags & MEM_Blob );
   pCrsr = pC->pCursor;
-  if( pCrsr!=0 ){
+  if( ALWAYS(pCrsr!=0) ){
     assert( pC->isTable==0 );
     rc = ExpandBlob(pIn2);
     if( rc==SQLITE_OK ){
@@ -4172,6 +4201,8 @@ case OP_IdxInsert: {        /* in2 */
 case OP_IdxDelete: {
   VdbeCursor *pC;
   BtCursor *pCrsr;
+  int res;
+  UnpackedRecord r;
 
   assert( pOp->p3>0 );
   assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem+1 );
@@ -4179,9 +4210,7 @@ case OP_IdxDelete: {
   pC = p->apCsr[pOp->p1];
   assert( pC!=0 );
   pCrsr = pC->pCursor;
-  if( pCrsr!=0 ){
-    int res;
-    UnpackedRecord r;
+  if( ALWAYS(pCrsr!=0) ){
     r.pKeyInfo = pC->pKeyInfo;
     r.nField = (u16)pOp->p3;
     r.flags = 0;
@@ -4213,9 +4242,9 @@ case OP_IdxRowid: {              /* out2-prerelease */
   pC = p->apCsr[pOp->p1];
   assert( pC!=0 );
   pCrsr = pC->pCursor;
-  if( pCrsr!=0 ){
+  if( ALWAYS(pCrsr!=0) ){
     rc = sqlite3VdbeCursorMoveto(pC);
-    if( rc ) goto abort_due_to_error;
+    if( NEVER(rc) ) goto abort_due_to_error;
     assert( pC->deferredMoveto==0 );
     assert( pC->isTable==0 );
     if( !pC->nullRow ){
@@ -4265,7 +4294,7 @@ case OP_IdxGE: {        /* jump, in3 */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   pC = p->apCsr[pOp->p1];
   assert( pC!=0 );
-  if( pC->pCursor!=0 ){
+  if( ALWAYS(pC->pCursor!=0) ){
     assert( pC->deferredMoveto==0 );
     assert( pOp->p5==0 || pOp->p5==1 );
     assert( pOp->p4type==P4_INT32 );
@@ -4469,7 +4498,7 @@ case OP_ParseSchema: {
   */
   assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
   sqlite3BtreeEnterAll(db);
-  if( pOp->p2 || DbHasProperty(db, iDb, DB_SchemaLoaded) ){
+  if( pOp->p2 || ALWAYS(DbHasProperty(db, iDb, DB_SchemaLoaded)) ){
     zMaster = SCHEMA_TABLE(iDb);
     initData.db = db;
     initData.iDb = pOp->p1;
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 33f8d60d51..109fca2e50 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -14,7 +14,7 @@
 ** to version 2.8.7, all this code was combined into the vdbe.c source file.
 ** But that file was getting too big so this subroutines were split out.
 **
-** $Id: vdbeaux.c,v 1.462 2009/06/22 00:55:31 drh Exp $
+** $Id: vdbeaux.c,v 1.463 2009/06/22 19:05:41 drh Exp $
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
@@ -2014,9 +2014,17 @@ void sqlite3VdbeDelete(Vdbe *p){
 }
 
 /*
+** Make sure the cursor p is ready to read or write the row to which it
+** was last positioned.  Return an error code if an OOM fault or I/O error
+** prevents us from positioning the cursor to its correct position.
+**
 ** If a MoveTo operation is pending on the given cursor, then do that
-** MoveTo now.  Return an error code.  If no MoveTo is pending, this
-** routine does nothing and returns SQLITE_OK.
+** MoveTo now.  If no move is pending, check to see if the row has been
+** deleted out from under the cursor and if it has, mark the row as
+** a NULL row.
+**
+** If the cursor is already pointing to the correct row and that row has
+** not been deleted out from under the cursor, then this routine is a no-op.
 */
 int sqlite3VdbeCursorMoveto(VdbeCursor *p){
   if( p->deferredMoveto ){
diff --git a/src/vdbemem.c b/src/vdbemem.c
index 80516ccef6..d92b496ea7 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -15,7 +15,7 @@
 ** only within the VDBE.  Interface routines refer to a Mem using the
 ** name sqlite_value
 **
-** $Id: vdbemem.c,v 1.148 2009/06/17 16:20:04 drh Exp $
+** $Id: vdbemem.c,v 1.149 2009/06/22 19:05:41 drh Exp $
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
@@ -637,6 +637,12 @@ void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
 ** string is copied into a (possibly existing) buffer managed by the 
 ** Mem structure. Otherwise, any existing buffer is freed and the
 ** pointer copied.
+**
+** If the string is too large (if it exceeds the SQLITE_LIMIT_LENGTH
+** size limit) then no memory allocation occurs.  If the string can be
+** stored without allocating memory, then it is.  If a memory allocation
+** is required to store the string, then value of pMem is unchanged.  In
+** either case, SQLITE_TOOBIG is returned.
 */
 int sqlite3VdbeMemSetStr(
   Mem *pMem,          /* Memory cell to set to string value */
@@ -700,9 +706,6 @@ int sqlite3VdbeMemSetStr(
     pMem->xDel = xDel;
     flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
   }
-  if( nByte>iLimit ){
-    return SQLITE_TOOBIG;
-  }
 
   pMem->n = nByte;
   pMem->flags = flags;
@@ -715,6 +718,10 @@ int sqlite3VdbeMemSetStr(
   }
 #endif
 
+  if( nByte>iLimit ){
+    return SQLITE_TOOBIG;
+  }
+
   return SQLITE_OK;
 }