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Differences Between: [Versions 310 and 400] [Versions 310 and 401] [Versions 310 and 402] [Versions 310 and 403]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Native postgresql recordset.
  19   *
  20   * @package    core_dml
  21   * @copyright  2008 Petr Skoda (http://skodak.org)
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  defined('MOODLE_INTERNAL') || die();
  26  
  27  require_once (__DIR__.'/moodle_recordset.php');
  28  
  29  /**
  30   * pgsql specific moodle recordset class
  31   *
  32   * @package    core_dml
  33   * @copyright  2008 Petr Skoda (http://skodak.org)
  34   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  35   */
  36  class pgsql_native_moodle_recordset extends moodle_recordset {
  37  
  38      protected $result;
  39      /** @var current row as array.*/
  40      protected $current;
  41      protected $blobs = array();
  42  
  43      /** @var string Name of cursor or '' if none */
  44      protected $cursorname;
  45  
  46      /** @var pgsql_native_moodle_database Postgres database resource */
  47      protected $db;
  48  
  49      /** @var bool True if there are no more rows to fetch from the cursor */
  50      protected $lastbatch;
  51  
  52      /**
  53       * Build a new recordset to iterate over.
  54       *
  55       * When using cursors, $result will be null initially.
  56       *
  57       * @param resource|null $result A pg_query() result object to create a recordset from.
  58       * @param pgsql_native_moodle_database $db Database object (only required when using cursors)
  59       * @param string $cursorname Name of cursor or '' if none
  60       */
  61      public function __construct($result, pgsql_native_moodle_database $db = null, $cursorname = '') {
  62          if ($cursorname && !$db) {
  63              throw new coding_exception('When specifying a cursor, $db is required');
  64          }
  65          $this->result = $result;
  66          $this->db = $db;
  67          $this->cursorname = $cursorname;
  68  
  69          // When there is a cursor, do the initial fetch.
  70          if ($cursorname) {
  71              $this->fetch_cursor_block();
  72          }
  73  
  74          // Find out if there are any blobs.
  75          $numfields = pg_num_fields($this->result);
  76          for ($i = 0; $i < $numfields; $i++) {
  77              $type = pg_field_type($this->result, $i);
  78              if ($type == 'bytea') {
  79                  $this->blobs[] = pg_field_name($this->result, $i);
  80              }
  81          }
  82  
  83          $this->current = $this->fetch_next();
  84      }
  85  
  86      /**
  87       * Fetches the next block of data when using cursors.
  88       *
  89       * @throws coding_exception If you call this when the fetch buffer wasn't freed yet
  90       */
  91      protected function fetch_cursor_block() {
  92          if ($this->result) {
  93              throw new coding_exception('Unexpected non-empty result when fetching from cursor');
  94          }
  95          list($this->result, $this->lastbatch) = $this->db->fetch_from_cursor($this->cursorname);
  96          if (!$this->result) {
  97              throw new coding_exception('Unexpected failure when fetching from cursor');
  98          }
  99      }
 100  
 101      public function __destruct() {
 102          $this->close();
 103      }
 104  
 105      private function fetch_next() {
 106          if (!$this->result) {
 107              return false;
 108          }
 109          if (!$row = pg_fetch_assoc($this->result)) {
 110              // There are no more rows in this result.
 111              pg_free_result($this->result);
 112              $this->result = null;
 113  
 114              // If using a cursor, can we fetch the next block?
 115              if ($this->cursorname && !$this->lastbatch) {
 116                  $this->fetch_cursor_block();
 117                  if (!$row = pg_fetch_assoc($this->result)) {
 118                      pg_free_result($this->result);
 119                      $this->result = null;
 120                      return false;
 121                  }
 122              } else {
 123                  return false;
 124              }
 125          }
 126  
 127          if ($this->blobs) {
 128              foreach ($this->blobs as $blob) {
 129                  $row[$blob] = $row[$blob] !== null ? pg_unescape_bytea($row[$blob]) : null;
 130              }
 131          }
 132  
 133          return $row;
 134      }
 135  
 136      public function current() {
 137          return (object)$this->current;
 138      }
 139  
 140      public function key() {
 141          // return first column value as key
 142          if (!$this->current) {
 143              return false;
 144          }
 145          $key = reset($this->current);
 146          return $key;
 147      }
 148  
 149      public function next() {
 150          $this->current = $this->fetch_next();
 151      }
 152  
 153      public function valid() {
 154          return !empty($this->current);
 155      }
 156  
 157      public function close() {
 158          if ($this->result) {
 159              pg_free_result($this->result);
 160              $this->result  = null;
 161          }
 162          $this->current = null;
 163          $this->blobs   = null;
 164  
 165          // If using cursors, close the cursor.
 166          if ($this->cursorname) {
 167              $this->db->close_cursor($this->cursorname);
 168              $this->cursorname = null;
 169          }
 170      }
 171  }