Fix issue 15261: Crash in history::TextDatabase::GetTextMatches...

third_party/sqlite/ext/fts2/fts2.c

 /* fts2 has a design flaw which can lead to database corruption (see
 ** below).  It is recommended not to use it any longer, instead use
 ** fts3 (or higher).  If you believe that your use of fts2 is safe,
 ** add -DSQLITE_ENABLE_BROKEN_FTS2=1 to your CFLAGS.
 */
 #if (!defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2)) \
         && !defined(SQLITE_ENABLE_BROKEN_FTS2)
 #error fts2 has a design flaw and has been deprecated.
 #endif
 /* The flaw is that fts2 uses the content table's unaliased rowid as
@@ skipping 354 matching lines @@
 */
 /* TODO(shess) The snippet-generation code should be using the
 ** tokenizer-generated tokens rather than doing its own local
 ** tokenization.
 */
 /* TODO(shess) Is __isascii() a portable version of (c&0x80)==0? */
 static int safe_isspace(char c){
   return (c&0x80)==0 ? isspace(c) : 0;
 }
 static int safe_tolower(char c){
-  return (c&0x80)==0 ? tolower(c) : c;
+  return (c>='A' && c<='Z') ? (c-'A'+'a') : c;
 }
 static int safe_isalnum(char c){
   return (c&0x80)==0 ? isalnum(c) : 0;
 }
 
 typedef enum DocListType {
   DL_DOCIDS,              /* docids only */
   DL_POSITIONS,           /* docids + positions */
   DL_POSITIONS_OFFSETS    /* docids + positions + offsets */
 } DocListType;
@@ skipping 6609 matching lines @@
   sqlite3 *db, 
   char **pzErrMsg,
   const sqlite3_api_routines *pApi
 ){
   SQLITE_EXTENSION_INIT2(pApi)
   return sqlite3Fts2Init(db);
 }
 #endif
 
 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */