From f8bdcfa3f17dead618d9f4f3d680f7a5cba4083b Mon Sep 17 00:00:00 2001
From: drh <>
Date: Sat, 9 Apr 2022 03:06:01 +0000
Subject: [PATCH] The sqlite3WhereMalloc() routine allocates memory that is
 automatically deleted when the corresponding WhereInfo object is destroyed.

FossilOrigin-Name: f237e1d8cc41b937f34288daebfacf5f7b0990a807a805e0cb6b45bc730192d6
---
 manifest        | 18 +++++++++---------
 manifest.uuid   |  2 +-
 src/where.c     | 37 +++++++++++++++++++++++++++++--------
 src/whereInt.h  | 13 +++++++++++++
 src/wherecode.c |  5 +++--
 src/whereexpr.c | 10 ++--------
 6 files changed, 57 insertions(+), 28 deletions(-)

diff --git a/manifest b/manifest
index 4dcfbdb9c9..bf8983c822 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Enhance\sthe\ssqlite_dbpage\sfix\sat\s[/info/642a0b4752743216|check-in\s642a0b4752743]\nfrom\sabout\sa\smonth\sago\ssuch\sthat\sit\sstill\stakes\sa\stransaction\son\sall\sattached\ndatabases,\sbut\sit\sonly\sstarts\sa\sread\stransaction\sfor\sread-only\soperations,\nrather\sthan\sstarting\sa\swrite\stransaction\sfor\severything.
-D 2022-04-08T17:01:29.519
+C The\ssqlite3WhereMalloc()\sroutine\sallocates\smemory\sthat\sis\sautomatically\ndeleted\swhen\sthe\scorresponding\sWhereInfo\sobject\sis\sdestroyed.
+D 2022-04-09T03:06:01.731
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -639,10 +639,10 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c b9df133a705093da8977da5eb202eaadb844839f1c7297c08d33471f5491843d
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
-F src/where.c a17d57807aa63dca4f3204d01db7a863bc0290bd7913928582236d65c9ad4212
-F src/whereInt.h 15d2975c3b4c193c78c26674400a840da8647fe1777ae3b026e2d15937b38a03
-F src/wherecode.c 6292d7bf2d751b1ce68139a70e5468dd6615a9a9dab5b5e61c0053836723bb7a
-F src/whereexpr.c 612f58f5f6e3e3bb94d10e2c56672ade8bbf94d4a928d3edb4e84e2ed3c00dca
+F src/where.c 929ac88a1b65bcdef7e05a0b87b13a0c55cd3d5d3bc27ec81a6f37eaca13e5fe
+F src/whereInt.h 41ce0a8c0368372d8422e420e05a1e037624ce52fae139c3c19538ee491fb4c0
+F src/wherecode.c b7bc24b150d6a47c48844f89c3bf6d8f694780acb71768c83b9bec8a729e0d81
+F src/whereexpr.c 2ce4ff64b80fce0a0f7579f5ec2b953f10952a3410c441564e12b650ea8c2aba
 F src/window.c 42a71595263dbd8ef8248218e4fc7d4b5ddccece52146ad48e079342d93f6f8f
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test ce1aafc86e110685b324e9a763eab4f2a73f737842ec3b687bd965867de90627
@@ -1945,8 +1945,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 48f2e5a1fbaa8ceb32e08066766be74233b0c67ab430bbf7adfdff42cdb7b8ec
-R 20c6686a28e5cb126a28d0c27a5e917b
+P 8efd61e8518594e3e9c84681fc35796a78fe8885a97ad4dd19f1573ee8065b18
+R 48010733dae82cb9023efd9a61e0d9ba
 U drh
-Z 5fb2265312a791be3cfc50f876b63b0a
+Z a50ac2a16236eccfde93e32da194e6bb
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 081aaf7939..0f6e9d2f91 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-8efd61e8518594e3e9c84681fc35796a78fe8885a97ad4dd19f1573ee8065b18
\ No newline at end of file
+f237e1d8cc41b937f34288daebfacf5f7b0990a807a805e0cb6b45bc730192d6
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index f08c350b06..4820a5c031 100644
--- a/src/where.c
+++ b/src/where.c
@@ -253,6 +253,30 @@ Bitmask sqlite3WhereGetMask(WhereMaskSet *pMaskSet, int iCursor){
   return 0;
 }
 
+/* Allocate memory that is automatically freed when pWInfo is freed.
+*/
+void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte){
+  WhereMemBlock *pBlock;
+  pBlock = sqlite3DbMallocRawNN(pWInfo->pParse->db, nByte+sizeof(*pBlock));
+  if( pBlock ){
+    pBlock->pNext = pWInfo->pMemToFree;
+    pBlock->sz = nByte;
+    pWInfo->pMemToFree = pBlock;
+    pBlock++;
+  }
+  return (void*)pBlock;
+}
+void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte){
+  void *pNew = sqlite3WhereMalloc(pWInfo, nByte);
+  if( pNew && pOld ){
+    WhereMemBlock *pOldBlk = (WhereMemBlock*)pOld;
+    pOldBlk--;
+    assert( pOldBlk->sz<nByte );
+    memcpy(pNew, pOld, pOldBlk->sz);
+  }
+  return pNew;
+}
+
 /*
 ** Create a new mask for cursor iCursor.
 **
@@ -2216,15 +2240,7 @@ static void whereLoopDelete(sqlite3 *db, WhereLoop *p){
 ** Free a WhereInfo structure
 */
 static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
-  int i;
   assert( pWInfo!=0 );
-  for(i=0; i<pWInfo->nLevel; i++){
-    WhereLevel *pLevel = &pWInfo->a[i];
-    if( pLevel->pWLoop && (pLevel->pWLoop->wsFlags & WHERE_IN_ABLE)!=0 ){
-      assert( (pLevel->pWLoop->wsFlags & WHERE_MULTI_OR)==0 );
-      sqlite3DbFree(db, pLevel->u.in.aInLoop);
-    }
-  }
   sqlite3WhereClauseClear(&pWInfo->sWC);
   while( pWInfo->pLoops ){
     WhereLoop *p = pWInfo->pLoops;
@@ -2232,6 +2248,11 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
     whereLoopDelete(db, p);
   }
   assert( pWInfo->pExprMods==0 );
+  while( pWInfo->pMemToFree ){
+    WhereMemBlock *pNext = pWInfo->pMemToFree->pNext;
+    sqlite3DbFreeNN(db, pWInfo->pMemToFree);
+    pWInfo->pMemToFree = pNext;
+  }
   sqlite3DbFreeNN(db, pWInfo);
 }
 
diff --git a/src/whereInt.h b/src/whereInt.h
index 3fc39f6b4a..e0f44d6bac 100644
--- a/src/whereInt.h
+++ b/src/whereInt.h
@@ -32,6 +32,16 @@ typedef struct WhereLoopBuilder WhereLoopBuilder;
 typedef struct WhereScan WhereScan;
 typedef struct WhereOrCost WhereOrCost;
 typedef struct WhereOrSet WhereOrSet;
+typedef struct WhereMemBlock WhereMemBlock;
+
+/*
+** This object is a header on a block of allocated memory that will be
+** automatically freed when its WInfo oject is destructed.
+*/
+struct WhereMemBlock {
+  WhereMemBlock *pNext;      /* Next block in the chain */
+  u8 sz;                     /* Bytes of space */
+};
 
 /*
 ** This object contains information needed to implement a single nested
@@ -478,6 +488,7 @@ struct WhereInfo {
   int iEndWhere;            /* End of the WHERE clause itself */
   WhereLoop *pLoops;        /* List of all WhereLoop objects */
   WhereExprMod *pExprMods;  /* Expression modifications */
+  WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */
   Bitmask revMask;          /* Mask of ORDER BY terms that need reversing */
   WhereClause sWC;          /* Decomposition of the WHERE clause */
   WhereMaskSet sMaskSet;    /* Map cursor numbers to bitmasks */
@@ -503,6 +514,8 @@ WhereTerm *sqlite3WhereFindTerm(
   u32 op,               /* Mask of WO_xx values describing operator */
   Index *pIdx           /* Must be compatible with this index, if not NULL */
 );
+void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte);
+void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte);
 
 /* wherecode.c: */
 #ifndef SQLITE_OMIT_EXPLAIN
diff --git a/src/wherecode.c b/src/wherecode.c
index bab514a693..561b34fc85 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -640,8 +640,9 @@ static int codeEqualityTerm(
     i = pLevel->u.in.nIn;
     pLevel->u.in.nIn += nEq;
     pLevel->u.in.aInLoop =
-       sqlite3DbReallocOrFree(pParse->db, pLevel->u.in.aInLoop,
-                              sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn);
+       sqlite3WhereRealloc(pTerm->pWC->pWInfo,
+                           pLevel->u.in.aInLoop,
+                           sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn);
     pIn = pLevel->u.in.aInLoop;
     if( pIn ){
       int iMap = 0;               /* Index in aiMap[] */
diff --git a/src/whereexpr.c b/src/whereexpr.c
index 26a521fffd..a3316db65b 100644
--- a/src/whereexpr.c
+++ b/src/whereexpr.c
@@ -64,7 +64,7 @@ static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){
   if( pWC->nTerm>=pWC->nSlot ){
     WhereTerm *pOld = pWC->a;
     sqlite3 *db = pWC->pWInfo->pParse->db;
-    pWC->a = sqlite3DbMallocRawNN(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
+    pWC->a = sqlite3WhereMalloc(pWC->pWInfo, sizeof(pWC->a[0])*pWC->nSlot*2 );
     if( pWC->a==0 ){
       if( wtFlags & TERM_DYNAMIC ){
         sqlite3ExprDelete(db, p);
@@ -73,10 +73,7 @@ static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){
       return 0;
     }
     memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
-    if( pOld!=pWC->aStatic ){
-      sqlite3DbFree(db, pOld);
-    }
-    pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
+    pWC->nSlot = pWC->nSlot*2;
   }
   pTerm = &pWC->a[idx = pWC->nTerm++];
   if( (wtFlags & TERM_VIRTUAL)==0 ) pWC->nBase = pWC->nTerm;
@@ -1686,9 +1683,6 @@ void sqlite3WhereClauseClear(WhereClause *pWC){
       a++;
     }
   }
-  if( pWC->a!=pWC->aStatic ){
-    sqlite3DbFree(db, pWC->a);
-  }
 }
 
 
-- 
2.47.2