/*

** 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 */