From: drh <>
Date: Fri, 21 Jul 2023 18:09:07 +0000 (+0000)
Subject: Further improvements to large string handling in relation to JSON.
X-Git-Tag: version-3.43.0~125^2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=569700a72e58a1cf9efc7fb743768a64cfd77d3c;p=thirdparty%2Fsqlite.git

Further improvements to large string handling in relation to JSON.

FossilOrigin-Name: 1e5df0aa3dae5cadbf1d07c718ae2a5212543300b68e49d35e8c96855a7f619c
---

diff --git a/manifest b/manifest
index b4f361aba9..0ff7e75f17 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sharmless\scompiler\swarning\sabout\ssigned/unsigned\scomparison.
-D 2023-07-21T15:07:56.630
+C Further\simprovements\sto\slarge\sstring\shandling\sin\srelation\sto\sJSON.
+D 2023-07-21T18:09:07.505
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -597,7 +597,7 @@ F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c 3f0a94082d978bbdd33c38fefea15346c6c6bffb70bc645a71dc0f1f87dd3276
-F src/json.c 2bf3223892b4b9be39d701a5d349efcce5f5eebf71baaf91ba5866e10127e839
+F src/json.c 46ea5566e1363f4f353db79b0378c2bf8ffdf9d4667daee3df67b14669767bed
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 176d6b2cb18a6ad73b133db17f6fc351c4d9a2d510deebdb76c22bde9cfd1465
 F src/main.c 512b1d45bc556edf4471a845afb7ba79e64bd5b832ab222dc195c469534cd002
@@ -709,11 +709,11 @@ F src/util.c fea6fffdee3cdae917a66b70deec59d4f238057cfd6de623d15cf990c196940d
 F src/vacuum.c 604fcdaebe76f3497c855afcbf91b8fa5046b32de3045bab89cc008d68e40104
 F src/vdbe.c 4cda877d413a18fa07346b08d6959b3d18ce982357921e7acb9649fca2534a12
 F src/vdbe.h 41485521f68e9437fdb7ec4a90f9d86ab294e9bb8281e33b235915e29122cfc0
-F src/vdbeInt.h 7bd49eef8f89c1a271fbf12d80a206bf56c876814c5fc6bee340f4e1907095ae
-F src/vdbeapi.c b8866af13401c9779759640457fa37dafe7bc2466c8428ade10ef625d012e52b
+F src/vdbeInt.h 401813862f9d75af01bdb2ab99253ad019e9d6ddcc8058e4fa61a43e9a60d1f7
+F src/vdbeapi.c dde6c4d0f87486f056b9db4d1ea185bb1d84a6839102b86e76316ba590d07cc7
 F src/vdbeaux.c b5e3f7e158518b4eca6f166ac43900640a3fe9735c710e12bfa119af21059339
 F src/vdbeblob.c 2516697b3ee8154eb8915f29466fb5d4f1ae39ee8b755ea909cefaf57ec5e2ce
-F src/vdbemem.c cf4a1556dd5b18c071cf7c243373c29ce752eb516022e3ad49ba72f08b785033
+F src/vdbemem.c d6588e873aec78077c95c95df03920a1bcff1ee59fe58579261c957bf6118988
 F src/vdbesort.c 0d40dca073c94e158ead752ef4225f4fee22dee84145e8c00ca2309afb489015
 F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf823
 F src/vdbevtab.c aae4bd769410eb7e1d02c42613eec961d514459b1c3c1c63cfc84e92a137daac
@@ -2043,8 +2043,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P d0278cdedfa04fb0b61838ab9622be8a2c462f58d5c3ebc4c5f802a727d0974e
-R e667842b6755e6f486934eef004d9f18
+P 75cc3c89ee2dcfefa9421ce60bee77e85d2895918e8c5cfd05c434f8932a99b5
+R b0bbcf196bde05ae8f599a4f16022c78
 U drh
-Z 993e102a87ed849f759c01f42525f684
+Z 8dfc9dc2f2e2752cbadaab8d45cf08cb
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 247f7c86b6..9ac6a758a7 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-75cc3c89ee2dcfefa9421ce60bee77e85d2895918e8c5cfd05c434f8932a99b5
\ No newline at end of file
+1e5df0aa3dae5cadbf1d07c718ae2a5212543300b68e49d35e8c96855a7f619c
\ No newline at end of file
diff --git a/src/json.c b/src/json.c
index a9425aecda..05046b5b54 100644
--- a/src/json.c
+++ b/src/json.c
@@ -501,8 +501,8 @@ static void jsonAppendValue(
 */
 static void jsonResult(JsonString *p){
   if( p->bErr==0 ){
-    if( p->nAlloc>=p->nUsed+1 ) p->zBuf[p->nUsed] = 0;
-    sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed,
+    jsonAppendChar(p, 0);
+    sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed-1,
                           p->bStatic ? SQLITE_TRANSIENT : sqlite3_free,
                           SQLITE_UTF8);
     jsonZero(p);
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index 4c3394716b..3a5b961a25 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -611,6 +611,7 @@ int sqlite3VdbeMemSetZeroBlob(Mem*,int);
 int sqlite3VdbeMemIsRowSet(const Mem*);
 #endif
 int sqlite3VdbeMemSetRowSet(Mem*);
+void sqlite3VdbeMemZeroTerminateIfAble(Mem*);
 int sqlite3VdbeMemMakeWriteable(Mem*);
 int sqlite3VdbeMemStringify(Mem*, u8, u8);
 int sqlite3IntFloatCompare(i64,double);
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index 079fb3976a..92bf38160f 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -514,15 +514,7 @@ void sqlite3_result_text64(
     (void)invokeValueDestructor(z, xDel, pCtx);
   }else{
     setResultStrOrError(pCtx, z, (int)n, enc, xDel);
-    if( xDel==sqlite3_free && enc==SQLITE_UTF8 ){
-      Mem *pOut = pCtx->pOut;
-      if( pOut->z==z 
-       && sqlite3_msize(pOut->z) >= (sqlite3_uint64)(pOut->n+1)
-       && pOut->z[n]==0
-      ){
-        pOut->flags |= MEM_Term;
-      }
-    }
+    sqlite3VdbeMemZeroTerminateIfAble(pCtx->pOut);
   }
 }
 #ifndef SQLITE_OMIT_UTF16
diff --git a/src/vdbemem.c b/src/vdbemem.c
index 1250eea77d..2baa35e24f 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -314,6 +314,32 @@ int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){
   return SQLITE_OK;
 }
 
+/*
+** If pMem is already a string, detect if it is a zero-terminated
+** string, or make it into one if possible, and mark it as such.
+**
+** This is an optimization.  Correct operation continues even if
+** this routine is a no-op.
+*/
+void sqlite3VdbeMemZeroTerminateIfAble(Mem *pMem){
+  if( (pMem->flags & (MEM_Str|MEM_Term))!=MEM_Str ) return;
+  if( pMem->enc!=SQLITE_UTF8 ) return;
+  if( pMem->z==0 ) return;
+  if( pMem->flags & MEM_Dyn ){
+    if( pMem->xDel==sqlite3_free
+     && sqlite3_msize(pMem->z) >= pMem->n+1
+     && pMem->z[pMem->n]==0 
+    ){
+      pMem->flags |= MEM_Term;
+      return;
+    }
+  }else if( pMem->szMalloc>0 && pMem->szMalloc >= pMem->n+1 ){
+    pMem->z[pMem->n] = 0;
+    pMem->flags |= MEM_Term;
+    return;
+  }
+}
+
 /*
 ** It is already known that pMem contains an unterminated string.
 ** Add the zero terminator.
@@ -803,6 +829,7 @@ int sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
       break;
     }
     default: {
+      int rc;
       assert( aff==SQLITE_AFF_TEXT );
       assert( MEM_Str==(MEM_Blob>>3) );
       pMem->flags |= (pMem->flags&MEM_Blob)>>3;
@@ -810,7 +837,9 @@ int sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
       assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
       pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal|MEM_Blob|MEM_Zero);
       if( encoding!=SQLITE_UTF8 ) pMem->n &= ~1;
-      return sqlite3VdbeChangeEncoding(pMem, encoding);
+      rc = sqlite3VdbeChangeEncoding(pMem, encoding);
+      if( rc ) return rc;
+      sqlite3VdbeMemZeroTerminateIfAble(pMem);
     }
   }
   return SQLITE_OK;