src/legacy.c

   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
  18 #include "sqliteInt.h"
  19
  20 /*
  21 ** Execute SQL code.  Return one of the SQLITE_ success/failure
  22 ** codes.  Also write an error message into memory obtained from
  23 ** malloc() and make *pzErrMsg point to that message.
  24 **
  25 ** If the SQL is a query, then for each row in the query result
  26 ** the xCallback() function is called.  pArg becomes the first
  27 ** argument to xCallback().  If xCallback=NULL then no callback
  28 ** is invoked, even for queries.
  29 */
  30 int sqlite3_exec(
  31   sqlite3 *db,                /* The database on which the SQL executes */
  32   const char *zSql,           /* The SQL to be executed */
  33   sqlite3_callback xCallback, /* Invoke this callback routine */
  34   void *pArg,                 /* First argument to xCallback() */
  35   char **pzErrMsg             /* Write error messages here */
  36 ){
  37   int rc = SQLITE_OK;         /* Return code */
  38   const char *zLeftover;      /* Tail of unprocessed SQL */
  39   sqlite3_stmt *pStmt = 0;    /* The current SQL statement */
  40   char **azCols = 0;          /* Names of result columns */
  41   int nRetry = 0;             /* Number of retry attempts */
  42   int callbackIsInit;         /* True if callback data is initialized */
  43
  44   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
  45   if( zSql==0 ) zSql = "";
  46
  47   sqlite3_mutex_enter(db->mutex);
  48   sqlite3Error(db, SQLITE_OK, 0);
  49   while( (rc==SQLITE_OK || (rc==SQLITE_SCHEMA && (++nRetry)<2)) && zSql[0] ){
  50     int nCol;
  51     char **azVals = 0;
  52
  53     pStmt = 0;
  54     rc = sqlite3_prepare(db, zSql, -1, &pStmt, &zLeftover);
  55     assert( rc==SQLITE_OK || pStmt==0 );
  56     if( rc!=SQLITE_OK ){
  57       continue;
  58     }
  59     if( !pStmt ){
  60       /* this happens for a comment or white-space */
  61       zSql = zLeftover;
  62       continue;
  63     }
  64
  65     callbackIsInit = 0;
  66     nCol = sqlite3_column_count(pStmt);
  67
  68     while( 1 ){
  69       int i;
  70       rc = sqlite3_step(pStmt);
  71
  72       /* Invoke the callback function if required */
  73       if( xCallback && (SQLITE_ROW==rc ||
  74           (SQLITE_DONE==rc && !callbackIsInit
  75                            && db->flags&SQLITE_NullCallback)) ){
  76         if( !callbackIsInit ){
  77           azCols = sqlite3DbMallocZero(db, 2*nCol*sizeof(const char*) + 1);
  78           if( azCols==0 ){
  79             goto exec_out;
  80           }
  81           for(i=0; i<nCol; i++){
  82             azCols[i] = (char *)sqlite3_column_name(pStmt, i);
  83             /* sqlite3VdbeSetColName() installs column names as UTF8
  84             ** strings so there is no way for sqlite3_column_name() to fail. */
  85             assert( azCols[i]!=0 );
  86           }
  87           callbackIsInit = 1;
  88         }
  89         if( rc==SQLITE_ROW ){
  90           azVals = &azCols[nCol];
  91           for(i=0; i<nCol; i++){
  92             azVals[i] = (char *)sqlite3_column_text(pStmt, i);
  93             if( !azVals[i] && sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){
  94               db->mallocFailed = 1;
  95               goto exec_out;
  96             }
  97           }
  98         }
  99         if( xCallback(pArg, nCol, azVals, azCols) ){
 100           rc = SQLITE_ABORT;
 101           sqlite3VdbeFinalize((Vdbe *)pStmt);
 102           pStmt = 0;
 103           sqlite3Error(db, SQLITE_ABORT, 0);
 104           goto exec_out;
 105         }
 106       }
 107
 108       if( rc!=SQLITE_ROW ){
 109         rc = sqlite3VdbeFinalize((Vdbe *)pStmt);
 110         pStmt = 0;
 111         if( rc!=SQLITE_SCHEMA ){
 112           nRetry = 0;
 113           zSql = zLeftover;
 114           while( sqlite3Isspace(zSql[0]) ) zSql++;
 115         }
 116         break;
 117       }
 118     }
 119
 120     sqlite3DbFree(db, azCols);
 121     azCols = 0;
 122   }
 123
 124 exec_out:
 125   if( pStmt ) sqlite3VdbeFinalize((Vdbe *)pStmt);
 126   sqlite3DbFree(db, azCols);
 127
 128   rc = sqlite3ApiExit(db, rc);
 129   if( rc!=SQLITE_OK && ALWAYS(rc==sqlite3_errcode(db)) && pzErrMsg ){
 130     int nErrMsg = 1 + sqlite3Strlen30(sqlite3_errmsg(db));
 131     *pzErrMsg = sqlite3Malloc(nErrMsg);
 132     if( *pzErrMsg ){
 133       memcpy(*pzErrMsg, sqlite3_errmsg(db), nErrMsg);
 134     }else{
 135       rc = SQLITE_NOMEM;
 136       sqlite3Error(db, SQLITE_NOMEM, 0);
 137     }
 138   }else if( pzErrMsg ){
 139     *pzErrMsg = 0;
 140   }
 141
 142   assert( (rc&db->errMask)==rc );
 143   sqlite3_mutex_leave(db->mutex);
 144   return rc;
 145 }