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Differences Between: [Versions 310 and 402] [Versions 311 and 402] [Versions 39 and 402] [Versions 400 and 402] [Versions 401 and 402]

   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      /** @var PgSql\Result|resource|null */
  39      protected $result;
  40      /** @var current row as array.*/
  41      protected $current;
  42      protected $blobs = array();
  43  
  44      /** @var string Name of cursor or '' if none */
  45      protected $cursorname;
  46  
  47      /** @var pgsql_native_moodle_database Postgres database resource */
  48      protected $db;
  49  
  50      /** @var bool True if there are no more rows to fetch from the cursor */
  51      protected $lastbatch;
  52  
  53      /**
  54       * Build a new recordset to iterate over.
  55       *
  56       * When using cursors, $result will be null initially.
  57       *
  58       * @param resource|PgSql\Result|null $result A pg_query() result object to create a recordset from.
  59       * @param pgsql_native_moodle_database $db Database object (only required when using cursors)
  60       * @param string $cursorname Name of cursor or '' if none
  61       */
  62      public function __construct($result, pgsql_native_moodle_database $db = null, $cursorname = '') {
  63          if ($cursorname && !$db) {
  64              throw new coding_exception('When specifying a cursor, $db is required');
  65          }
  66          $this->result = $result;
  67          $this->db = $db;
  68          $this->cursorname = $cursorname;
  69  
  70          // When there is a cursor, do the initial fetch.
  71          if ($cursorname) {
  72              $this->fetch_cursor_block();
  73          }
  74  
  75          // Find out if there are any blobs.
  76          $numfields = pg_num_fields($this->result);
  77          for ($i = 0; $i < $numfields; $i++) {
  78              $type = $this->db->pg_field_type($this->result, $i);
  79              if ($type == 'bytea') {
  80                  $this->blobs[] = pg_field_name($this->result, $i);
  81              }
  82          }
  83  
  84          $this->current = $this->fetch_next();
  85      }
  86  
  87      /**
  88       * Fetches the next block of data when using cursors.
  89       *
  90       * @throws coding_exception If you call this when the fetch buffer wasn't freed yet
  91       */
  92      protected function fetch_cursor_block() {
  93          if ($this->result) {
  94              throw new coding_exception('Unexpected non-empty result when fetching from cursor');
  95          }
  96          list($this->result, $this->lastbatch) = $this->db->fetch_from_cursor($this->cursorname);
  97          if (!$this->result) {
  98              throw new coding_exception('Unexpected failure when fetching from cursor');
  99          }
 100      }
 101  
 102      public function __destruct() {
 103          $this->close();
 104      }
 105  
 106      private function fetch_next() {
 107          if (!$this->result) {
 108              return false;
 109          }
 110          if (!$row = pg_fetch_assoc($this->result)) {
 111              // There are no more rows in this result.
 112              pg_free_result($this->result);
 113              $this->result = null;
 114  
 115              // If using a cursor, can we fetch the next block?
 116              if ($this->cursorname && !$this->lastbatch) {
 117                  $this->fetch_cursor_block();
 118                  if (!$row = pg_fetch_assoc($this->result)) {
 119                      pg_free_result($this->result);
 120                      $this->result = null;
 121                      return false;
 122                  }
 123              } else {
 124                  return false;
 125              }
 126          }
 127  
 128          if ($this->blobs) {
 129              foreach ($this->blobs as $blob) {
 130                  $row[$blob] = $row[$blob] !== null ? pg_unescape_bytea($row[$blob]) : null;
 131              }
 132          }
 133  
 134          return $row;
 135      }
 136  
 137      public function current(): stdClass {
 138          return (object)$this->current;
 139      }
 140  
 141      #[\ReturnTypeWillChange]
 142      public function key() {
 143          // return first column value as key
 144          if (!$this->current) {
 145              return false;
 146          }
 147          $key = reset($this->current);
 148          return $key;
 149      }
 150  
 151      public function next(): void {
 152          $this->current = $this->fetch_next();
 153      }
 154  
 155      public function valid(): bool {
 156          return !empty($this->current);
 157      }
 158  
 159      public function close() {
 160          if ($this->result) {
 161              pg_free_result($this->result);
 162              $this->result  = null;
 163          }
 164          $this->current = null;
 165          $this->blobs   = null;
 166  
 167          // If using cursors, close the cursor.
 168          if ($this->cursorname) {
 169              $this->db->close_cursor($this->cursorname);
 170              $this->cursorname = null;
 171          }
 172      }
 173  }