/*

 ** 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.

 **

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

 ** This file contains the sqlite3_get_table() and sqlite3_free_table()

 ** interface routines.  These are just wrappers around the main

 ** interface routine of sqlite3_exec().

 **

 ** These routines are in a separate files so that they will not be linked

 ** if they are not used.

 */

 #include "sqliteInt.h"

 #include <stdlib.h>

 #include <string.h>

 #ifndef SQLITE_OMIT_GET_TABLE

 /*

 ** This structure is used to pass data from sqlite3_get_table() through

 ** to the callback function is uses to build the result.

 */

 typedef struct TabResult {

   char **azResult;

   char *zErrMsg;

   int nResult;

   int nAlloc;

   int nRow;

   int nColumn;

   int nData;

   int rc;

 } TabResult;

 /*

 ** This routine is called once for each row in the result table.  Its job

 ** is to fill in the TabResult structure appropriately, allocating new

 ** memory as necessary.

 */

 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){

   TabResult *p = (TabResult*)pArg;

   int need;

   int i;

   char *z;

   /* Make sure there is enough space in p->azResult to hold everything

   ** we need to remember from this invocation of the callback.

   */

   if( p->nRow==0 && argv!=0 ){

     need = nCol*2;

   }else{

     need = nCol;

   }

   if( p->nData + need >= p->nAlloc ){

     char **azNew;

     p->nAlloc = p->nAlloc*2 + need + 1;

     azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc );

     if( azNew==0 ) goto malloc_failed;

     p->azResult = azNew;

   }

   /* If this is the first row, then generate an extra row containing

   ** the names of all columns.

   */

   if( p->nRow==0 ){

     p->nColumn = nCol;

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

       if( colv[i]==0 ){

         z = sqlite3_mprintf("");

       }else{

         z = sqlite3_mprintf("%s", colv[i]);

       }

       p->azResult[p->nData++] = z;

     }

   }else if( p->nColumn!=nCol ){

     sqlite3SetString(&p->zErrMsg,

        "sqlite3_get_table() called with two or more incompatible queries",

        (char*)0);

     p->rc = SQLITE_ERROR;

     return 1;

   }

   /* Copy over the row data

   */

   if( argv!=0 ){

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

       if( argv[i]==0 ){

         z = 0;

       }else{

         int n = strlen(argv[i])+1;

         z = sqlite3_malloc( n );

         if( z==0 ) goto malloc_failed;

         memcpy(z, argv[i], n);

       }

       p->azResult[p->nData++] = z;

     }

     p->nRow++;

   }

   return 0;

 malloc_failed:

   p->rc = SQLITE_NOMEM;

   return 1;

 }

 /*

 ** Query the database.  But instead of invoking a callback for each row,

 ** malloc() for space to hold the result and return the entire results

 ** at the conclusion of the call.

 **

 ** The result that is written to ***pazResult is held in memory obtained

 ** from malloc().  But the caller cannot free this memory directly.  

 ** Instead, the entire table should be passed to sqlite3_free_table() when

 ** the calling procedure is finished using it.

 */

 int sqlite3_get_table(

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

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

   char ***pazResult,          /* Write the result table here */

   int *pnRow,                 /* Write the number of rows in the result here */

   int *pnColumn,              /* Write the number of columns of result here */

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

 ){

   int rc;

   TabResult res;

   if( pazResult==0 ){ return SQLITE_ERROR; }

   *pazResult = 0;

   if( pnColumn ) *pnColumn = 0;

   if( pnRow ) *pnRow = 0;

   res.zErrMsg = 0;

   res.nResult = 0;

   res.nRow = 0;

   res.nColumn = 0;

   res.nData = 1;

   res.nAlloc = 20;

   res.rc = SQLITE_OK;

   res.azResult = sqlite3_malloc( sizeof(char*)*res.nAlloc );

   if( res.azResult==0 ) return SQLITE_NOMEM;

   res.azResult[0] = 0;

   rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg);

 #ifndef NDEBUG

   sqlite3_mutex_enter(db->mutex);

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

   sqlite3_mutex_leave(db->mutex);

 #endif

   if( res.azResult ){

     assert( sizeof(res.azResult[0])>= sizeof(res.nData) );

     res.azResult[0] = (char*)res.nData;

   }

   if( (rc&0xff)==SQLITE_ABORT ){

     sqlite3_free_table(&res.azResult[1]);

     if( res.zErrMsg ){

       if( pzErrMsg ){

         sqlite3_free(*pzErrMsg);

         *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg);

       }

       sqlite3_free(res.zErrMsg);

     }

     sqlite3_mutex_enter(db->mutex);

     db->errCode = res.rc;

     sqlite3_mutex_leave(db->mutex);

     return res.rc;

   }

   sqlite3_free(res.zErrMsg);

   if( rc!=SQLITE_OK ){

     sqlite3_free_table(&res.azResult[1]);

     return rc;

   }

   if( res.nAlloc>res.nData ){

     char **azNew;

     azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) );

     if( azNew==0 ){

       sqlite3_free_table(&res.azResult[1]);

       return SQLITE_NOMEM;

     }

     res.nAlloc = res.nData+1;

     res.azResult = azNew;

   }

   *pazResult = &res.azResult[1];

   if( pnColumn ) *pnColumn = res.nColumn;

   if( pnRow ) *pnRow = res.nRow;

   return rc;

 }

 /*

 ** This routine frees the space the sqlite3_get_table() malloced.

 */

 void sqlite3_free_table(

   char **azResult            /* Result returned from from sqlite3_get_table() */

 ){

   if( azResult ){

     int i, n;

     azResult--;

     if( azResult==0 ) return;

     n = (int)azResult[0];

     for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); }

     sqlite3_free(azResult);

   }

 }

 #endif /* SQLITE_OMIT_GET_TABLE */