Remove an unnecessary conditional, replacing it with an assert().

Improvements to comments.

FossilOrigin-Name: 834bf1c367e1ccd498c7f9f843be2d2aa11ffb3c

diff --git a/manifest b/manifest
index a1eded678c7b91aa160d416e3b80b6473d952ff5..dbe10602d3f6660db5b16285d0423e7d710cb9e5 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\scompiler\swarning\swhen\sSQLITE_DIRECT_OVERFLOW_READ\sis\sdefined.\nMinor\sperformance\senhancement\sand\ssize\sreduction.
-D 2014-03-31T23:57:41.627
+C Remove\san\sunnecessary\sconditional,\sreplacing\sit\swith\san\sassert().\nImprovements\sto\scomments.
+D 2014-04-01T01:24:34.512
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 2ef13430cd359f7b361bb863504e227b25cc7f81
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -164,7 +164,7 @@ F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c a729e63cf5cd1829507cb7b8e89f99b95141bb53
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c b1d6309d6623f4ea8d9466aebd1ec84adc40cb9b
+F src/btree.c 6c9b51abd404ce5b78b173b6f2248e8cb824758c
 F src/btree.h d79306df4ed9181b48916737fe8871a4392c4594
 F src/btreeInt.h cf180d86b2e9e418f638d65baa425c4c69c0e0e3
 F src/build.c 0d50ef95aad63f4c4fc47f3fa2670d4557c45db0
@@ -1159,7 +1159,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P f6211540c9d66a08dc580dd733e4f4a98968ae30
-R a9646e8cad6830bc030ac01ef7720050
+P 96385dc460545807a5c8fcf6280a971700f84866
+R 193f537069a669cf49d79f97b46daa7e
 U drh
-Z be4271c513a3efe06acb17f300ec9933
+Z 9306db9f51cd1c998fccb67bf7fedc94

diff --git a/manifest.uuid b/manifest.uuid
index e03a98f749b86ddead3d9519a66a30e511ceb942..44d48365ac85744adf3a079b0c652e9f5a3aa9ba 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-96385dc460545807a5c8fcf6280a971700f84866
\ No newline at end of file
+834bf1c367e1ccd498c7f9f843be2d2aa11ffb3c
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index cbb968ad8be6646e9dad6194203ee6204a69d357..2bf026b840861d0bdd2b734cc77edccda8bca77a 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -3974,6 +3974,7 @@ static int accessPayload(
   assert( pCur->eState==CURSOR_VALID );
   assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
   assert( cursorHoldsMutex(pCur) );
+  assert( eOp!=2 || offset==0 );      /* Always start from beginning for eOp==2 */
 
   getCellInfo(pCur);
   aPayload = pCur->info.pCell + pCur->info.nHeader;
@@ -4009,12 +4010,13 @@ static int accessPayload(
 
     nextPage = get4byte(&aPayload[pCur->info.nLocal]);
 
-    /* If the BTCF_Incrblob flag is set and the BtCursor.aOverflow[]
-    ** has not been allocated, allocate it now. The array is sized at
-    ** one entry for each overflow page in the overflow chain. The
-    ** page number of the first overflow page is stored in aOverflow[0],
-    ** etc. A value of 0 in the aOverflow[] array means "not yet known"
-    ** (the cache is lazily populated).
+    /* If the BtCursor.aOverflow[] has not been allocated, allocate it now.
+    ** Except, do not allocate aOverflow[] for eOp==2.
+    **
+    ** The aOverflow[] array is sized at one entry for each overflow page
+    ** in the overflow chain. The page number of the first overflow page is
+    ** stored in aOverflow[0], etc. A value of 0 in the aOverflow[] array
+    ** means "not yet known" (the cache is lazily populated).
     */
     if( eOp!=2 && (pCur->curFlags & BTCF_ValidOvfl)==0 ){
       int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
@@ -4059,11 +4061,17 @@ static int accessPayload(
         ** data is not required. So first try to lookup the overflow
         ** page-list cache, if any, then fall back to the getOverflowPage()
         ** function.
+        **
+        ** Note that the aOverflow[] array must be allocated because eOp!=2
+        ** here.  If eOp==2, then offset==0 and this branch is never taken.
         */
-        if( (pCur->curFlags & BTCF_ValidOvfl)!=0 && pCur->aOverflow[iIdx+1] ){
+        assert( eOp!=2 );
+        assert( pCur->curFlags & BTCF_ValidOvfl );
+        if( pCur->aOverflow[iIdx+1] ){
           nextPage = pCur->aOverflow[iIdx+1];
-        } else 
+        }else{
           rc = getOverflowPage(pBt, nextPage, 0, &nextPage);
+        }
         offset -= ovflSize;
       }else{
         /* Need to read this page properly. It contains some of the