[sql] Import reference version of SQLite 3.8.7.4.

third_party/sqlite/sqlite-src-3080704/src/vdbetrace.c

 /*
 ** 2009 November 25
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
 ** This file contains code used to insert the values of host parameters
 ** (aka "wildcards") into the SQL text output by sqlite3_trace().
+**
+** The Vdbe parse-tree explainer is also found here.
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
 
 #ifndef SQLITE_OMIT_TRACE
 
 /*
 ** zSql is a zero-terminated string of UTF-8 SQL text.  Return the number of
 ** bytes in this text up to but excluding the first character in
 ** a host parameter.  If the text contains no host parameters, return
@@ skipping 13 matching lines @@
       break;
     }
     nTotal += n;
     zSql += n;
   }
   return nTotal;
 }
 
 /*
 ** This function returns a pointer to a nul-terminated string in memory
-** obtained from sqlite3DbMalloc(). If sqlite3.vdbeExecCnt is 1, then the
+** obtained from sqlite3DbMalloc(). If sqlite3.nVdbeExec is 1, then the
 ** string contains a copy of zRawSql but with host parameters expanded to 
-** their current bindings. Or, if sqlite3.vdbeExecCnt is greater than 1, 
+** their current bindings. Or, if sqlite3.nVdbeExec is greater than 1, 
 ** then the returned string holds a copy of zRawSql with "-- " prepended
 ** to each line of text.
 **
+** If the SQLITE_TRACE_SIZE_LIMIT macro is defined to an integer, then
+** then long strings and blobs are truncated to that many bytes.  This
+** can be used to prevent unreasonably large trace strings when dealing
+** with large (multi-megabyte) strings and blobs.
+**
 ** The calling function is responsible for making sure the memory returned
 ** is eventually freed.
 **
 ** ALGORITHM:  Scan the input string looking for host parameters in any of
 ** these forms:  ?, ?N, $A, @A, :A.  Take care to avoid text within
 ** string literals, quoted identifier names, and comments.  For text forms,
-** the host parameter index is found by scanning the perpared
+** the host parameter index is found by scanning the prepared
 ** statement for the corresponding OP_Variable opcode.  Once the host
 ** parameter index is known, locate the value in p->aVar[].  Then render
 ** the value as a literal in place of the host parameter name.
 */
 char *sqlite3VdbeExpandSql(
   Vdbe *p,                 /* The prepared statement being evaluated */
   const char *zRawSql      /* Raw text of the SQL statement */
 ){
   sqlite3 *db;             /* The database connection */
   int idx = 0;             /* Index of a host parameter */
   int nextIndex = 1;       /* Index of next ? host parameter */
   int n;                   /* Length of a token prefix */
   int nToken;              /* Length of the parameter token */
   int i;                   /* Loop counter */
   Mem *pVar;               /* Value of a host parameter */
   StrAccum out;            /* Accumulate the output here */
   char zBase[100];         /* Initial working space */
 
   db = p->db;
   sqlite3StrAccumInit(&out, zBase, sizeof(zBase), 
                       db->aLimit[SQLITE_LIMIT_LENGTH]);
   out.db = db;
-  if( db->vdbeExecCnt>1 ){
+  if( db->nVdbeExec>1 ){
     while( *zRawSql ){
       const char *zStart = zRawSql;
       while( *(zRawSql++)!='\n' && *zRawSql );
       sqlite3StrAccumAppend(&out, "-- ", 3);
+      assert( (zRawSql - zStart) > 0 );
       sqlite3StrAccumAppend(&out, zStart, (int)(zRawSql-zStart));
     }
   }else{
     while( zRawSql[0] ){
       n = findNextHostParameter(zRawSql, &nToken);
       assert( n>0 );
       sqlite3StrAccumAppend(&out, zRawSql, n);
       zRawSql += n;
       assert( zRawSql[0] || nToken==0 );
       if( nToken==0 ) break;
@@ skipping 12 matching lines @@
         idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
         assert( idx>0 );
       }
       zRawSql += nToken;
       nextIndex = idx + 1;
       assert( idx>0 && idx<=p->nVar );
       pVar = &p->aVar[idx-1];
       if( pVar->flags & MEM_Null ){
         sqlite3StrAccumAppend(&out, "NULL", 4);
       }else if( pVar->flags & MEM_Int ){
-        sqlite3XPrintf(&out, "%lld", pVar->u.i);
+        sqlite3XPrintf(&out, 0, "%lld", pVar->u.i);
       }else if( pVar->flags & MEM_Real ){
-        sqlite3XPrintf(&out, "%!.15g", pVar->r);
+        sqlite3XPrintf(&out, 0, "%!.15g", pVar->u.r);
       }else if( pVar->flags & MEM_Str ){
+        int nOut;  /* Number of bytes of the string text to include in output */
 #ifndef SQLITE_OMIT_UTF16
         u8 enc = ENC(db);
+        Mem utf8;
         if( enc!=SQLITE_UTF8 ){
-          Mem utf8;
           memset(&utf8, 0, sizeof(utf8));
           utf8.db = db;
           sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
           sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8);
-          sqlite3XPrintf(&out, "'%.*q'", utf8.n, utf8.z);
-          sqlite3VdbeMemRelease(&utf8);
-        }else
+          pVar = &utf8;
+        }
 #endif
-        {
-          sqlite3XPrintf(&out, "'%.*q'", pVar->n, pVar->z);
+        nOut = pVar->n;
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut>SQLITE_TRACE_SIZE_LIMIT ){
+          nOut = SQLITE_TRACE_SIZE_LIMIT;
+          while( nOut<pVar->n && (pVar->z[nOut]&0xc0)==0x80 ){ nOut++; }
         }
+#endif    
+        sqlite3XPrintf(&out, 0, "'%.*q'", nOut, pVar->z);
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut<pVar->n ){
+          sqlite3XPrintf(&out, 0, "/*+%d bytes*/", pVar->n-nOut);
+        }
+#endif
+#ifndef SQLITE_OMIT_UTF16
+        if( enc!=SQLITE_UTF8 ) sqlite3VdbeMemRelease(&utf8);
+#endif
       }else if( pVar->flags & MEM_Zero ){
-        sqlite3XPrintf(&out, "zeroblob(%d)", pVar->u.nZero);
+        sqlite3XPrintf(&out, 0, "zeroblob(%d)", pVar->u.nZero);
       }else{
+        int nOut;  /* Number of bytes of the blob to include in output */
         assert( pVar->flags & MEM_Blob );
         sqlite3StrAccumAppend(&out, "x'", 2);
-        for(i=0; i<pVar->n; i++){
-          sqlite3XPrintf(&out, "%02x", pVar->z[i]&0xff);
+        nOut = pVar->n;
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut>SQLITE_TRACE_SIZE_LIMIT ) nOut = SQLITE_TRACE_SIZE_LIMIT;
+#endif
+        for(i=0; i<nOut; i++){
+          sqlite3XPrintf(&out, 0, "%02x", pVar->z[i]&0xff);
         }
         sqlite3StrAccumAppend(&out, "'", 1);
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut<pVar->n ){
+          sqlite3XPrintf(&out, 0, "/*+%d bytes*/", pVar->n-nOut);
+        }
+#endif
       }
     }
   }
   return sqlite3StrAccumFinish(&out);
 }
 
 #endif /* #ifndef SQLITE_OMIT_TRACE */