db_postgres/res.c

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/*
 * $Id: res.c 5438 2009-01-09 13:23:11Z henningw $
 *
 * Copyright (C) 2003 August.Net Services, LLC
 * Copyright (C) 2006 Norman Brandinger
 * Copyright (C) 2008 1&1 Internet AG
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History
 * -------
 * 2003-04-06 initial code written (Greg Fausak/Andy Fullford)
 *
 * 2006-07-26 added BPCHAROID as a valid type for DB_STRING conversions
 *            this removes the "unknown type 1042" log messages (norm)
 *
 * 2006-10-27 Added fetch support (norm)
 *            Removed dependency on aug_* memory routines (norm)
 *            Added connection pooling support (norm)
 *            Standardized API routines to pg_* names (norm)
 */

/*! \file
 *  \brief DB_POSTGRES :: Core
 *  \ingroup db_postgres
 *  Module: \ref db_postgres
 */

#include <stdlib.h>
#include <string.h>
#include "../../db/db_id.h"
#include "../../db/db_res.h"
#include "../../db/db_con.h"
#include "../../dprint.h"
#include "../../mem/mem.h"
#include "res.h"
#include "val.h"
#include "pg_con.h"
#include "pg_type.h"


/*!
 * \brief Fill the result structure with data from the query
 * \param _h database connection
 * \param _r result set
 * \return 0 on success, negative on error
 */
int db_postgres_convert_result(const db_con_t* _h, db_res_t* _r)
{
   if (!_h || !_r)  {
      LM_ERR("invalid parameter value\n");
      return -1;
   }

   if (db_postgres_get_columns(_h, _r) < 0) {
      LM_ERR("failed to get column names\n");
      return -2;
   }

   if (db_postgres_convert_rows(_h, _r) < 0) {
      LM_ERR("failed to convert rows\n");
      db_free_columns(_r);
      return -3;
   }
   return 0;
}


/*!
 * \brief Get and convert columns from a result set
 * \param _h database connection
 * \param _r result set
 * \return 0 on success, negative on error
 */
int db_postgres_get_columns(const db_con_t* _h, db_res_t* _r)
{
   int col, datatype;

   if (!_h || !_r)  {
      LM_ERR("invalid parameter value\n");
      return -1;
   }

   /* Get the number of rows (tuples) in the query result. */
   RES_ROW_N(_r) = PQntuples(CON_RESULT(_h));

   /* Get the number of columns (fields) in each row of the query result. */
   RES_COL_N(_r) = PQnfields(CON_RESULT(_h));

   if (!RES_COL_N(_r)) {
      LM_DBG("no columns returned from the query\n");
      return -2;
   } else {
      LM_DBG("%d columns returned from the query\n", RES_COL_N(_r));
   }

   if (db_allocate_columns(_r, RES_COL_N(_r)) != 0) {
      LM_ERR("could not allocate columns\n");
      return -3;
   }

   /* For each column both the name and the OID number of the data type are saved. */
   for(col = 0; col < RES_COL_N(_r); col++) {

      RES_NAMES(_r)[col] = (str*)pkg_malloc(sizeof(str));
      if (! RES_NAMES(_r)[col]) {
         LM_ERR("no private memory left\n");
         db_free_columns(_r);
         return -4;
      }
      LM_DBG("allocate %d bytes for RES_NAMES[%d] at %p\n", (unsigned int) sizeof(str), col,
            RES_NAMES(_r)[col]);

      /* The pointer that is here returned is part of the result structure. */
      RES_NAMES(_r)[col]->s = PQfname(CON_RESULT(_h), col);
      RES_NAMES(_r)[col]->len = strlen(PQfname(CON_RESULT(_h), col));

      LM_DBG("RES_NAMES(%p)[%d]=[%.*s]\n", RES_NAMES(_r)[col], col,
            RES_NAMES(_r)[col]->len, RES_NAMES(_r)[col]->s);

      /* get the datatype of the column */
      switch(datatype = PQftype(CON_RESULT(_h),col))
      {
         case INT2OID:
         case INT4OID:
            LM_DBG("use DB_INT result type\n");
            RES_TYPES(_r)[col] = DB_INT;
         break;

         case INT8OID:
            LM_DBG("use DB_BIGINT result type\n");
            RES_TYPES(_r)[col] = DB_BIGINT;

         case FLOAT4OID:
         case FLOAT8OID:
         case NUMERICOID:
            LM_DBG("use DB_DOUBLE result type\n");
            RES_TYPES(_r)[col] = DB_DOUBLE;
         break;

         case DATEOID:
         case TIMESTAMPOID:
         case TIMESTAMPTZOID:
            LM_DBG("use DB_DATETIME result type\n");
            RES_TYPES(_r)[col] = DB_DATETIME;
         break;

         case BOOLOID:
         case CHAROID:
         case VARCHAROID:
         case BPCHAROID:
            LM_DBG("use DB_STRING result type\n");
            RES_TYPES(_r)[col] = DB_STRING;
         break;

         case TEXTOID:
         case BYTEAOID:
            LM_DBG("use DB_BLOB result type\n");
            RES_TYPES(_r)[col] = DB_BLOB;
         break;

         case BITOID:
         case VARBITOID:
            LM_DBG("use DB_BITMAP result type\n");
            RES_TYPES(_r)[col] = DB_BITMAP;
         break;
            
         default:
            LM_WARN("unhandled data type column (%.*s) type id (%d), "
                  "use DB_STRING as default\n", RES_NAMES(_r)[col]->len,
                  RES_NAMES(_r)[col]->s, datatype);
            RES_TYPES(_r)[col] = DB_STRING;
         break;
      }
   }
   return 0;
}


/*!
 * \brief Convert rows from PostgreSQL to db API representation
 * \param _h database connection
 * \param _r result set
 * \return 0 on success, negative on error
 */
int db_postgres_convert_rows(const db_con_t* _h, db_res_t* _r)
{
   char **row_buf, *s;
   int row, col, len;

   if (!_h || !_r)  {
      LM_ERR("invalid parameter\n");
      return -1;
   }

   if (!RES_ROW_N(_r)) {
      LM_DBG("no rows returned from the query\n");
      RES_ROWS(_r) = 0;
      return 0;
   }
   /*Allocate an array of pointers per column to holds the string representation */
   len = sizeof(char *) * RES_COL_N(_r);
   row_buf = (char**)pkg_malloc(len);
   if (!row_buf) {
      LM_ERR("no private memory left\n");
      return -1;
   }
   LM_DBG("allocate for %d columns %d bytes in row buffer at %p\n", RES_COL_N(_r), len, row_buf);
   memset(row_buf, 0, len);

   if (db_allocate_rows(_r) < 0) {
      LM_ERR("could not allocate rows\n");
      LM_DBG("freeing row buffer at %p\n", row_buf);
      pkg_free(row_buf);
      return -2;
   }

   for(row = RES_LAST_ROW(_r); row < (RES_LAST_ROW(_r) + RES_ROW_N(_r)); row++) {
      for(col = 0; col < RES_COL_N(_r); col++) {
         /*
          * The row data pointer returned by PQgetvalue points to storage
          * that is part of the PGresult structure. One should not modify
          * the data it points to, and one must explicitly copy the data
          * into other storage if it is to be used past the lifetime of
          * the PGresult structure itself.
          */
         s = PQgetvalue(CON_RESULT(_h), row, col);
         LM_DBG("PQgetvalue(%p,%d,%d)=[%s]\n", _h, row, col, s);
         /*
          * A empty string can be a NULL value, or just an empty string.
          * This differs from the mysql behaviour, that further processing
          * steps expect. So we need to simulate this here unfortunally.
          */
         if (PQgetisnull(CON_RESULT(_h), row, col) == 0) {
            row_buf[col] = s;
            LM_DBG("[%d][%d] Column[%.*s]=[%s]\n",
               row, col, RES_NAMES(_r)[col]->len, RES_NAMES(_r)[col]->s, row_buf[col]);
         }
      }

      /* ASSERT: row_buf contains an entire row in strings */
      if(db_postgres_convert_row(_h, _r, &(RES_ROWS(_r)[row - RES_LAST_ROW(_r)]), row_buf)<0){
         LM_ERR("failed to convert row #%d\n",  row);
         RES_ROW_N(_r) = row - RES_LAST_ROW(_r);
         LM_DBG("freeing row buffer at %p\n", row_buf);
         pkg_free(row_buf);
         db_free_rows(_r);
         return -4;
      }
   }

   LM_DBG("freeing row buffer at %p\n", row_buf);
   pkg_free(row_buf);
   row_buf = NULL;
   return 0;
}


/*!
 * \brief Convert a row from the result query into db API representation
 * \param _h database connection
 * \param _r result set
 * \param _row row
 * \param row_buf row buffer
 * \return 0 on success, negative on error
 */
int db_postgres_convert_row(const db_con_t* _h, db_res_t* _r, db_row_t* _row,
      char **row_buf)
{
   int col, col_len;

   if (!_h || !_r || !_row)  {
      LM_ERR("invalid parameter value\n");
      return -1;
   }

   if (db_allocate_row(_r, _row) != 0) {
      LM_ERR("could not allocate row\n");
      return -2;
   }

   /* For each column in the row */
   for(col = 0; col < ROW_N(_row); col++) {
      /* because it can contain NULL */
      if (!row_buf[col]) {
         col_len = 0;
      } else {
         col_len = strlen(row_buf[col]);
      }
      /* Convert the string representation into the value representation */
      if (db_postgres_str2val(RES_TYPES(_r)[col], &(ROW_VALUES(_row)[col]),
      row_buf[col], col_len) < 0) {
         LM_ERR("failed to convert value\n");
         LM_DBG("free row at %p\n", _row);
         db_free_row(_row);
         return -3;
      }
   }
   return 0;
}