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Differences Between: [Versions 39 and 310] [Versions 39 and 311] [Versions 39 and 400] [Versions 39 and 401] [Versions 39 and 402] [Versions 39 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   * Defines abstract factory class for generating locks.
  19   *
  20   * @package    core
  21   * @copyright  Damyon Wiese 2013
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  namespace core\lock;
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  /**
  30   * Defines abstract factory class for generating locks.
  31   *
  32   * @package   core
  33   * @category  lock
  34   * @copyright Damyon Wiese 2013
  35   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  36   */
  37  interface lock_factory {
  38  
  39      /**
  40       * Define the constructor signature required by the lock_config class.
  41       *
  42       * @param string $type - The type this lock is used for (e.g. cron, cache)
  43       */
  44      public function __construct($type);
  45  
  46      /**
  47       * Return information about the blocking behaviour of the locks on this platform.
  48       *
  49       * @return boolean - False if attempting to get a lock will block indefinitely.
  50       */
  51      public function supports_timeout();
  52  
  53      /**
  54       * Will this lock be automatically released when the process ends.
  55       * This should never be relied upon in code - but is useful in the case of
  56       * fatal errors. If a lock type does not support this auto release,
  57       * the max lock time parameter must be obeyed to eventually clean up a lock.
  58       *
  59       * @return boolean - True if this lock type will be automatically released when the current process ends.
  60       */
  61      public function supports_auto_release();
  62  
  63      /**
  64       * Supports recursion.
  65       *
  66       * @return boolean - True if attempting to get 2 locks on the same resource will "stack"
  67       */
  68      public function supports_recursion();
  69  
  70      /**
  71       * Is available.
  72       *
  73       * @return boolean - True if this lock type is available in this environment.
  74       */
  75      public function is_available();
  76  
  77      /**
  78       * Get a lock within the specified timeout or return false.
  79       *
  80       * @param string $resource - The identifier for the lock. Should use frankenstyle prefix.
  81       * @param int $timeout - The number of seconds to wait for a lock before giving up.
  82       *                       Not all lock types will support this.
  83       * @param int $maxlifetime - The number of seconds to wait before reclaiming a stale lock.
  84       *                       Not all lock types will use this - e.g. if they support auto releasing
  85       *                       a lock when a process ends.
  86       * @return \core\lock\lock|boolean - An instance of \core\lock\lock if the lock was obtained, or false.
  87       */
  88      public function get_lock($resource, $timeout, $maxlifetime = 86400);
  89  
  90      /**
  91       * Release a lock that was previously obtained with @lock.
  92       *
  93       * @param lock $lock - The lock to release.
  94       * @return boolean - True if the lock is no longer held (including if it was never held).
  95       */
  96      public function release_lock(lock $lock);
  97  
  98      /**
  99       * Extend the timeout on a held lock.
 100       *
 101       * @param lock $lock - lock obtained from this factory
 102       * @param int $maxlifetime - new max time to hold the lock
 103       * @return boolean - True if the lock was extended.
 104       */
 105      public function extend_lock(lock $lock, $maxlifetime = 86400);
 106  }