/*

 ** 2001 September 15

 **

 ** 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.

 **

 *************************************************************************

 ** Main file for the SQLite library.  The routines in this file

 ** implement the programmer interface to the library.  Routines in

 ** other files are for internal use by SQLite and should not be

 ** accessed by users of the library.

 **

 ** $Id$

 */

 #include "sqliteInt.h"

 #include <ctype.h>

 /*

 ** Execute SQL code.  Return one of the SQLITE_ success/failure

 ** codes.  Also write an error message into memory obtained from

 ** malloc() and make *pzErrMsg point to that message.

 **

 ** If the SQL is a query, then for each row in the query result

 ** the xCallback() function is called.  pArg becomes the first

 ** argument to xCallback().  If xCallback=NULL then no callback

 ** is invoked, even for queries.

 */

 int sqlite3_exec(

   sqlite3 *db,                /* The database on which the SQL executes */

   const char *zSql,           /* The SQL to be executed */

   sqlite3_callback xCallback, /* Invoke this callback routine */

   void *pArg,                 /* First argument to xCallback() */

   char **pzErrMsg             /* Write error messages here */

 ){

   int rc = SQLITE_OK;

   const char *zLeftover;

   sqlite3_stmt *pStmt = 0;

   char **azCols = 0;

   int nRetry = 0;

   int nCallback;

   if( zSql==0 ) return SQLITE_OK;

   sqlite3_mutex_enter(db->mutex);

   while( (rc==SQLITE_OK || (rc==SQLITE_SCHEMA && (++nRetry)<2)) && zSql[0] ){

     int nCol;

     char **azVals = 0;

     pStmt = 0;

     rc = sqlite3_prepare(db, zSql, -1, &pStmt, &zLeftover);

     assert( rc==SQLITE_OK || pStmt==0 );

     if( rc!=SQLITE_OK ){

       continue;

     }

     if( !pStmt ){

       /* this happens for a comment or white-space */

       zSql = zLeftover;

       continue;

     }

     nCallback = 0;

     nCol = sqlite3_column_count(pStmt);

     azCols = sqlite3DbMallocZero(db, 2*nCol*sizeof(const char *) + 1);

     if( azCols==0 ){

       goto exec_out;

     }

     while( 1 ){

       int i;

       rc = sqlite3_step(pStmt);

       /* Invoke the callback function if required */

       if( xCallback && (SQLITE_ROW==rc || 

           (SQLITE_DONE==rc && !nCallback && db->flags&SQLITE_NullCallback)) ){

         if( 0==nCallback ){

           for(i=0; i<nCol; i++){

             azCols[i] = (char *)sqlite3_column_name(pStmt, i);

           }

           nCallback++;

         }

         if( rc==SQLITE_ROW ){

           azVals = &azCols[nCol];

           for(i=0; i<nCol; i++){

             azVals[i] = (char *)sqlite3_column_text(pStmt, i);

           }

         }

         if( xCallback(pArg, nCol, azVals, azCols) ){

           rc = SQLITE_ABORT;

           goto exec_out;

         }

       }

       if( rc!=SQLITE_ROW ){

         rc = sqlite3_finalize(pStmt);

         pStmt = 0;

         if( rc!=SQLITE_SCHEMA ){

           nRetry = 0;

           zSql = zLeftover;

           while( isspace((unsigned char)zSql[0]) ) zSql++;

         }

         break;

       }

     }

     sqlite3_free(azCols);

     azCols = 0;

   }

 exec_out:

   if( pStmt ) sqlite3_finalize(pStmt);

   if( azCols ) sqlite3_free(azCols);

   rc = sqlite3ApiExit(db, rc);

   if( rc!=SQLITE_OK && rc==sqlite3_errcode(db) && pzErrMsg ){

     int nErrMsg = 1 + strlen(sqlite3_errmsg(db));

     *pzErrMsg = sqlite3_malloc(nErrMsg);

     if( *pzErrMsg ){

       memcpy(*pzErrMsg, sqlite3_errmsg(db), nErrMsg);

     }

   }else if( pzErrMsg ){

     *pzErrMsg = 0;

   }

   assert( (rc&db->errMask)==rc );

   sqlite3_mutex_leave(db->mutex);

   return rc;

 }