lib/classes/php_time_limit.php

   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 }