Change an unreachable branch into an assert() in sqlite3PagerAcquire()

and optimize sqlite3PcacheOpenSavepoint() by factoring out rarely used code
into a subroutine.

FossilOrigin-Name: b406b20ecdf0bff63c5c222fab11cb9acee86765

manifest

@@ -1,5 +1,5 @@
-C Optimization\sto\sthe\ssqlite3PcacheFetch()\slogic.
+C Change\san\sunreachable\sbranch\sinto\san\sassert()\sin\ssqlite3PagerAcquire()\nand\soptimize\ssqlite3PcacheOpenSavepoint()\sby\sfactoring\sout\srarely\sused\scode\ninto\sa\ssubroutine.
-D 2015-06-30T03:57:59.045
+D 2015-06-30T11:07:32.245
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 285a0a234ed7610d431d91671c136098c2bd86a9
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -314,7 +314,7 @@ F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
 F src/os_unix.c 23eb5f56fac54d8fe0cb204291f3b3b2d94f23fc
 F src/os_win.c 27cc135e2d0b8b1e2e4944db1e2669a6a18fa0f8
 F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca
-F src/pager.c 3fa869dafdb59ece9d318177e3b9972039dfee39
+F src/pager.c 922d8ea28387b79a117488da06ee84f77d50d71e
 F src/pager.h c3476e7c89cdf1c6914e50a11f3714e30b4e0a77
 F src/parse.y 6d60dda8f8d418b6dc034f1fbccd816c459983a8
 F src/pcache.c cde06aa50962595e412d497e22fd2e07878ba1f0
@@ -1364,7 +1364,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P a0fa6b3ba59716e53b8c035b497602050ed0ccb8
+P d9a0481ce0fd9824b1566f182d68ec46ef091b1b
-R ef96145c17347794d738ef415b1d0f04
+R 24b6e6de7d9b089958239ab689d72050
 U drh
-Z a3fb1d60e02fc08f324c2aa0fa9d650d
+Z 9400732c29ac033e0975f1d6b596266c

manifest.uuid

@@ -1 +1 @@
-d9a0481ce0fd9824b1566f182d68ec46ef091b1b
+b406b20ecdf0bff63c5c222fab11cb9acee86765

src/pager.c

@@ -5319,7 +5319,7 @@ int sqlite3PagerAcquire(
         }
       }
       pPg = *ppPage = sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pBase);
-      if( pPg==0 ) rc = SQLITE_NOMEM;
+      assert( pPg!=0 );
     }
   }
 
@@ -6475,54 +6475,62 @@ int sqlite3PagerIsMemdb(Pager *pPager){
 ** occurs while opening the sub-journal file, then an IO error code is
 ** returned. Otherwise, SQLITE_OK.
 */
-int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
+static SQLITE_NOINLINE int pagerOpenSavepoint(Pager *pPager, int nSavepoint){
   int rc = SQLITE_OK;                       /* Return code */
   int nCurrent = pPager->nSavepoint;        /* Current number of savepoints */
+  int ii;                                   /* Iterator variable */
+  PagerSavepoint *aNew;                     /* New Pager.aSavepoint array */
 
   assert( pPager->eState>=PAGER_WRITER_LOCKED );
   assert( assert_pager_state(pPager) );
+  assert( nSavepoint>nCurrent && pPager->useJournal );
 
-  if( nSavepoint>nCurrent && pPager->useJournal ){
+  /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
-    int ii;                                 /* Iterator variable */
+  ** if the allocation fails. Otherwise, zero the new portion in case a 
-    PagerSavepoint *aNew;                   /* New Pager.aSavepoint array */
+  ** malloc failure occurs while populating it in the for(...) loop below.
+  */
+  aNew = (PagerSavepoint *)sqlite3Realloc(
+      pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
+  );
+  if( !aNew ){
+    return SQLITE_NOMEM;
+  }
+  memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
+  pPager->aSavepoint = aNew;
 
-    /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
+  /* Populate the PagerSavepoint structures just allocated. */
-    ** if the allocation fails. Otherwise, zero the new portion in case a 
+  for(ii=nCurrent; ii<nSavepoint; ii++){
-    ** malloc failure occurs while populating it in the for(...) loop below.
+    aNew[ii].nOrig = pPager->dbSize;
-    */
+    if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
-    aNew = (PagerSavepoint *)sqlite3Realloc(
+      aNew[ii].iOffset = pPager->journalOff;
-        pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
+    }else{
-    );
+      aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
-    if( !aNew ){
+    }
+    aNew[ii].iSubRec = pPager->nSubRec;
+    aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
+    if( !aNew[ii].pInSavepoint ){
       return SQLITE_NOMEM;
     }
-    memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
+    if( pagerUseWal(pPager) ){
-    pPager->aSavepoint = aNew;
+      sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
-
-    /* Populate the PagerSavepoint structures just allocated. */
-    for(ii=nCurrent; ii<nSavepoint; ii++){
-      aNew[ii].nOrig = pPager->dbSize;
-      if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
-        aNew[ii].iOffset = pPager->journalOff;
-      }else{
-        aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
-      }
-      aNew[ii].iSubRec = pPager->nSubRec;
-      aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
-      if( !aNew[ii].pInSavepoint ){
-        return SQLITE_NOMEM;
-      }
-      if( pagerUseWal(pPager) ){
-        sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
-      }
-      pPager->nSavepoint = ii+1;
     }
-    assert( pPager->nSavepoint==nSavepoint );
+    pPager->nSavepoint = ii+1;
-    assertTruncateConstraint(pPager);
   }
-
+  assert( pPager->nSavepoint==nSavepoint );
+  assertTruncateConstraint(pPager);
   return rc;
 }
+int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+
+  if( nSavepoint>pPager->nSavepoint && pPager->useJournal ){
+    return pagerOpenSavepoint(pPager, nSavepoint);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
 
 /*
 ** This function is called to rollback or release (commit) a savepoint.