1 /*

     2 ** 2001 September 15

     3 **

     4 ** The author disclaims copyright to this source code.  In place of

     5 ** a legal notice, here is a blessing:

     6 **

     7 **    May you do good and not evil.

     8 **    May you find forgiveness for yourself and forgive others.

     9 **    May you share freely, never taking more than you give.

    10 **

    11 *************************************************************************

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

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

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

    15 ** accessed by users of the library.

    16 **

    17 ** $Id: legacy.c,v 1.29 2008/08/02 03:50:39 drh Exp $

    18 */

    19 

    20 #include "sqliteInt.h"

    21 #include <ctype.h>

    22 

    23 /*

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

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

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

    27 **

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

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

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

    31 ** is invoked, even for queries.

    32 */

    33 int sqlite3_exec(

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

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

    36   sqlite3_callback xCallback, /* Invoke this callback routine */

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

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

    39 ){

    40   int rc = SQLITE_OK;

    41   const char *zLeftover;

    42   sqlite3_stmt *pStmt = 0;

    43   char **azCols = 0;

    44 

    45   int nRetry = 0;

    46   int nCallback;

    47 

    48   if( zSql==0 ) zSql = "";

    49 

    50   sqlite3_mutex_enter(db->mutex);

    51   sqlite3Error(db, SQLITE_OK, 0);

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

    53     int nCol;

    54     char **azVals = 0;

    55 

    56     pStmt = 0;

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

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

    59     if( rc!=SQLITE_OK ){

    60       continue;

    61     }

    62     if( !pStmt ){

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

    64       zSql = zLeftover;

    65       continue;

    66     }

    67 

    68     nCallback = 0;

    69     nCol = sqlite3_column_count(pStmt);

    70 

    71     while( 1 ){

    72       int i;

    73       rc = sqlite3_step(pStmt);

    74 

    75       /* Invoke the callback function if required */

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

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

    78         if( 0==nCallback ){

    79           if( azCols==0 ){

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

    81             if( azCols==0 ){

    82               goto exec_out;

    83             }

    84           }

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

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

    87             /* sqlite3VdbeSetColName() installs column names as UTF8

    88             ** strings so there is no way for sqlite3_column_name() to fail. */

    89             assert( azCols[i]!=0 );

    90           }

    91           nCallback++;

    92         }

    93         if( rc==SQLITE_ROW ){

    94           azVals = &azCols[nCol];

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

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

    97             if( !azVals[i] && sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){

    98               db->mallocFailed = 1;

    99               goto exec_out;

   100             }

   101           }

   102         }

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

   104           rc = SQLITE_ABORT;

   105           sqlite3_finalize(pStmt);

   106           pStmt = 0;

   107           sqlite3Error(db, SQLITE_ABORT, 0);

   108           goto exec_out;

   109         }

   110       }

   111 

   112       if( rc!=SQLITE_ROW ){

   113         rc = sqlite3_finalize(pStmt);

   114         pStmt = 0;

   115         if( rc!=SQLITE_SCHEMA ){

   116           nRetry = 0;

   117           zSql = zLeftover;

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

   119         }

   120         break;

   121       }

   122     }

   123 

   124     sqlite3DbFree(db, azCols);

   125     azCols = 0;

   126   }

   127 

   128 exec_out:

   129   if( pStmt ) sqlite3_finalize(pStmt);

   130   sqlite3DbFree(db, azCols);

   131 

   132   rc = sqlite3ApiExit(db, rc);

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

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

   135     *pzErrMsg = sqlite3Malloc(nErrMsg);

   136     if( *pzErrMsg ){

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

   138     }

   139   }else if( pzErrMsg ){

   140     *pzErrMsg = 0;

   141   }

   142 

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

   144   sqlite3_mutex_leave(db->mutex);

   145   return rc;

   146 }