answers.lock.inc in Answers 7.4

Same filename and directory in other branches

Question locking functions for the 'Answers' module.

The Answers module allow questions to be "locked". This means that users are no longer permitted to provide new answers. Users may still comment on and edit answers (and, depending on how permissions are set, users may comment on and edit questions).

Other modules may want to change their behavior based on whether a question is locked. For exmaple, the best answer module does not permit question authors to set or change best answers for locked questions.

The logic about *when* to lock or unlock questions is set by other modules. The answers module (and this file) only provides the API. When several modules are using locks, the rule for combining results is that if *any* module wants a question locked, then it is locked.

Users who have the "manage answers content" permission are not impacted by question locks. The can still add answers and change best answers. Site administrators may wish to give this permission to content editors.

To support locking, this file provides a hook and some utility functions.

The hook:

hook_answers_lock_info(): Modules that want to lock or unlock questions define this hook. It should return TRUE if the module will participate in locking.

The utility functions:

answers_question_lock_set($question, $module): Lock a specific question
answers_question_lock_unset($question, $module): Unlock a specific question
answers_question_locked_p($question): Returns non-null if question is locked

File

includes/answers.lock.inc

View source

<?php

/**
 * @file
 * Question locking functions for the 'Answers' module.
 *
 * The Answers module allow questions to be "locked". This means that users are
 * no longer permitted to provide new answers. Users may still comment on and
 * edit answers (and, depending on how permissions are set, users may comment on
 * and edit questions).
 *
 * Other modules may want to change their behavior based on whether a question
 * is locked. For exmaple, the best answer module does not permit question
 * authors to set or change best answers for locked questions.
 *
 * The logic about *when* to lock or unlock questions is set by other modules.
 * The answers module (and this file) only provides  the API. When several
 * modules are using locks, the rule for combining results is that if *any*
 * module wants a question locked, then it is locked.
 *
 * Users who have the "manage answers content" permission are not impacted by
 * question locks. The can still add answers and change best answers. Site
 * administrators may wish to give this permission to content editors.
 *
 * To support locking, this file provides a hook and some utility functions.
 *
 * The hook:
 *   - hook_answers_lock_info(): Modules that want to lock or unlock questions
 *     define this hook.
 *     It should return TRUE if the module will participate in locking.
 *
 * The utility functions:
 *    - answers_question_lock_set($question, $module):
 *        Lock a specific question
 *    - answers_question_lock_unset($question, $module):
 *        Unlock a specific question
 *    - answers_question_locked_p($question):
 *        Returns non-null if question is locked
 */

/**
 * Determine which modules have a stake in locking questions.
 */
function answers_locking_modules() {
  $locks =& drupal_static(__FUNCTION__);
  if (!isset($locks)) {

    // Try to get from cache.
    if ($cache = cache_get('answers_locking_modules')) {
      $locks = $cache->data;
    }
    if (!$locks) {
      $locks = array();
      foreach (module_implements('answers_lock_info') as $module) {
        if (module_invoke($module, 'answers_lock_info')) {
          $locks[$module] = $module;
        }
      }
      cache_set('answers_locking_modules', $locks, 'cache', CACHE_TEMPORARY);
    }
  }
  return $locks;
}

/**
 * Clear locking information cache.
 */
function answers_reset_lock_info() {
  drupal_static_reset('answers_locking_modules');
  cache_clear_all('answers_locking_modules', 'cache');
}

/**
 * Lock a question.
 *
 * @param object $question
 *   A fully loaded question node.
 * @param string $module
 *   The module setting the lock.
 */
function answers_question_lock_set($question, $module) {
  if (in_array($module, answers_locking_modules())) {
    $items = field_get_items('node', $question, 'question_locks');

    // Check if the question is already locked by this module.
    if (!$items || array_search(array(
      'value' => $module,
    ), $items) === FALSE) {

      // Find the delta.
      $delta = count($items);
      $lang = field_language('node', $question, 'question_locks');
      $question->question_locks[$lang][$delta]['value'] = $module;
      node_save($question);
    }
  }
}

/**
 * Unlock a question.
 *
 * @param object $question
 *   A fully loaded question node.
 * @param string $module
 *   The module that set the lock.
 */
function answers_question_lock_unset($question, $module) {
  if (in_array($module, answers_locking_modules())) {
    $items = field_get_items('node', $question, 'question_locks');

    // If the question is locked by this module, unset the lock.
    if ($items && ($delta = array_search(array(
      'value' => $module,
    ), $items) !== FALSE)) {
      $lang = field_language('node', $question, 'question_locks');
      $count = count($items);

      // Copy elements of lock array down.
      for ($i = $delta; $i < $count - 1; $i++) {
        $question->question_locks[$lang][$i] = $question->question_locks[$lang][$i + 1];
      }

      // Delete last element of lock array.
      unset($question->question_locks[$lang][$count - 1]);
      node_save($question);
    }
  }
}

/**
 * Indicate whether a question is locked or not.
 *
 * @param object $question
 *   A question node.
 */
function answers_question_locked_p($question) {
  $items = field_get_items('node', $question, 'question_locks');
  if (!$items) {
    return FALSE;
  }
  $modules = array();
  foreach ($items as $module) {
    $modules[] = $module['value'];
  }

  // Compare the list with only currently locking modules.
  return count(array_intersect($modules, answers_locking_modules())) > 0;
}

/**
 * Implements hook_query_TAG_alter().
 *
 * The 'question_locked' tag modifies the query to return only those
 * questions which are locked.
 */
function answers_query_question_locked_alter(QueryAlterableInterface $query) {
  $query
    ->innerJoin('field_data_question_locks', 'l', 'node.nid = l.entity_id AND l.entity_type = :entity_type', array(
    ':entity_type' => 'node',
  ));
}

/**
 * Implements hook_query_TAG_alter().
 *
 * The 'question_unlocked' tag modifies the query to return only those
 * questions which are not locked.
 */
function answers_query_question_unlocked_alter(QueryAlterableInterface $query) {
  $query
    ->leftJoin('field_data_question_locks', 'l', 'node.nid = l.entity_id AND l.entity_type = :entity_type', array(
    ':entity_type' => 'node',
  ));
  $query
    ->isNull('l.question_locks_value');
}

Functions

Name	Description
answers_locking_modules	Determine which modules have a stake in locking questions.
answers_query_question_locked_alter	Implements hook_query_TAG_alter().
answers_query_question_unlocked_alter	Implements hook_query_TAG_alter().
answers_question_locked_p	Indicate whether a question is locked or not.
answers_question_lock_set	Lock a question.
answers_question_lock_unset	Unlock a question.
answers_reset_lock_info	Clear locking information cache.

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answers.lock.inc in Answers 7.4

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