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   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   * PHP time limit management.
  19   *
  20   * @package core
  21   * @copyright 2013 The Open University
  22   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  defined('MOODLE_INTERNAL') || die();
  26  
  27  /**
  28   * Utility class to manage PHP time limit.
  29   */
  30  class core_php_time_limit {
  31      /**
  32       * @var int Current end time of time limit (-1 if not set)
  33       */
  34      protected static $currentend = -1;
  35  
  36      /**
  37       * @var array Data for unit testing
  38       */
  39      protected static $unittestdata = array();
  40  
  41      /**
  42       * Sets the PHP time limit to a number of seconds from now.
  43       *
  44       * This function will always extend the time limit (in other words, if the time
  45       * limit has already been set further in the future, it will do nothing).
  46       *
  47       * In order to support front-end servers which may time out silently if no
  48       * output is displayed, you should ideally only call this function if you expect
  49       * some output to be displayed at the same time. (I.e. if you call this function
  50       * each time around a loop, also display some output each time around the loop,
  51       * such as a progress bar update.)
  52       *
  53       * @param int $newlimit Limit in seconds from now (0 = infinite)
  54       */
  55      public static function raise($newlimit = 0) {
  56          global $CFG;
  57  
  58          // Special behaviour in unit tests so that we can check the value.
  59          if (PHPUNIT_TEST) {
  60              self::$unittestdata[] = $newlimit;
  61          }
  62  
  63          // If the time limit has already been set to 'infinite', ignore. Also do
  64          // nothing in CLI scripts (including unit testing) which are set to
  65          // infinite by default.
  66          if (self::$currentend === 0 || CLI_SCRIPT) {
  67              return;
  68          }
  69  
  70          // Maximum time limit can be set in config. This can be useful for front-end
  71          // server systems; if the front-end server has a timeout without receiving
  72          // data, it's helpful to set this timeout lower to ensure that a suitable
  73          // error gets logged.
  74          if (!empty($CFG->maxtimelimit)) {
  75              $realtimeout = max(1, $CFG->maxtimelimit);
  76              if ($newlimit === 0) {
  77                  $newlimit = $realtimeout;
  78              } else {
  79                  $newlimit = min($newlimit, $realtimeout);
  80              }
  81          }
  82  
  83          // If new time limit is infinite, just set that.
  84          if ($newlimit === 0) {
  85              self::$currentend = 0;
  86              @set_time_limit(0);
  87              return;
  88          }
  89  
  90          // Calculate time limits to make sure it's longer than previous.
  91          $now = time();
  92          $newend = $now + $newlimit;
  93          if (self::$currentend !== -1 && self::$currentend > $newend) {
  94              // Existing time limit is already longer, so do nothing.
  95              return;
  96          }
  97  
  98          // Set time limit and update current value.
  99          @set_time_limit($newlimit);
 100          self::$currentend = $newend;
 101      }
 102  
 103      /**
 104       * For unit testing, returns an array of the values set during test.
 105       *
 106       * @return array Array of values set
 107       */
 108      public static function get_and_clear_unit_test_data() {
 109          $data = self::$unittestdata;
 110          self::$unittestdata = array();
 111          return $data;
 112      }
 113  }