module.inc 5.34 KB
Newer Older
1 2 3
<?php
// $Id$

4 5 6 7 8
/**
 * @file
 * API for loading and interacting with Drupal modules.
 */

9 10 11 12 13 14
/**
 * Initialize all modules.
 *
 * To change the required set of modules, change this function as well as
 * system_listing() and module_list().
 */
15
function module_init() {
Dries's avatar
 
Dries committed
16
  module_load_all();
17
  module_invoke_all('init');
18 19
}

20 21 22 23
/**
 * Call a function repeatedly with each module in turn as an argument.
 */
function module_iterate($function, $argument = '') {
Kjartan's avatar
Kjartan committed
24 25 26
  foreach (module_list() as $name) {
    $function($name, $argument);
  }
27 28
}

29 30 31 32 33 34 35 36 37 38 39 40 41 42
/**
 * Collect a list of all installed and enabled modules.
 *
 * @param $refresh
 *   Whether to force the module list to be regenerated (such as after the
 *   administrator has changed the system settings).
 * @param $bootstrap
 *   Whether to return the reduced set of modules loaded in "bootstrap mode" for
 *   cached pages. See bootstrap.inc.
 * @return
 *   An associative array whose keys and values are the names of all loaded
 *   modules.
 */
function module_list($refresh = FALSE, $bootstrap = FALSE) {
43 44
  static $list;

Dries's avatar
 
Dries committed
45 46 47 48
  if ($refresh) {
    unset($list);
  }

49
  if (!$list) {
50
    $list = array('admin' => 'admin', 'filter' => 'filter', 'system' => 'system', 'user' => 'user', 'watchdog' => 'watchdog');
51 52 53 54 55 56
    if ($bootstrap) {
      $result = db_query("SELECT name, filename, throttle, bootstrap FROM {system} WHERE type = 'module' AND status = 1 AND bootstrap = 1");
    }
    else {
      $result = db_query("SELECT name, filename, throttle, bootstrap FROM {system} WHERE type = 'module' AND status = 1");
    }
57
    while ($module = db_fetch_object($result)) {
Dries's avatar
 
Dries committed
58
      if (file_exists($module->filename)) {
59 60 61
        // Determine the current throttle status and see if the module should be
        // loaded based on server load. We have to directly access the throttle
        // variables, since throttle.module may not be loaded yet.
62
        $throttle = ($module->throttle && variable_get('throttle_level', 0) > 0);
63
        if (!$throttle) {
Dries's avatar
Dries committed
64
          drupal_get_filename('module', $module->name, $module->filename);
Dries's avatar
 
Dries committed
65 66
          $list[$module->name] = $module->name;
        }
67
      }
68
    }
Dries's avatar
 
Dries committed
69
    asort($list);
70 71 72 73
  }
  return $list;
}

Dries's avatar
 
Dries committed
74 75 76 77
/**
 * Load all the modules that have been enabled in the system table.
 *
 * @return
Dries's avatar
Dries committed
78
 *   TRUE if all modules were loaded successfully.
Dries's avatar
 
Dries committed
79 80 81
 */
function module_load_all() {
  $list = module_list();
Dries's avatar
Dries committed
82 83
  $status = TRUE;

Dries's avatar
 
Dries committed
84
  foreach ($list as $module) {
Dries's avatar
Dries committed
85
    $status = (drupal_load('module', $module) && $status);
Dries's avatar
 
Dries committed
86
  }
Dries's avatar
Dries committed
87

Dries's avatar
 
Dries committed
88 89 90 91
  return $status;
}


92 93 94 95 96 97 98 99 100
/**
 * Determine whether a given module exists.
 *
 * @param $module
 *   The name of the module (without the .module extension).
 * @return
 *   TRUE if the module is both installed and enabled.
 */
function module_exist($module) {
101
  $list = module_list();
102
  return array_key_exists($module, $list);
103 104
}

105 106
/**
 * @defgroup hooks Hooks
Dries's avatar
 
Dries committed
107 108
 * @{
 * Allow modules to interact with the Drupal core.
109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138
 *
 * Drupal's module system is based on the concept of "hooks". A hook is a PHP
 * function that is named foo_bar(), where "foo" is the name of the module (whose
 * filename is thus foo.module) and "bar" is the name of the hook. Each hook has
 * a defined set of parameters and a specified result type.
 *
 * To extend Drupal, a module need simply implement a hook. When Drupal wishes to
 * allow intervention from modules, it determines which modules implement a hook
 * and call that hook in all enabled modules that implement it.
 *
 * The available hooks to implement are explained here in the Hooks section of
 * the developer documentation. The string "hook" is used as a placeholder for
 * the module name is the hook definitions. For example, if the module file is
 * called example.module, then hook_help() as implemented by that module would be
 * defined as example_help().
 */

/**
 * Determine whether a module implements a hook.
 *
 * @param $module
 *   The name of the module (without the .module extension).
 * @param $hook
 *   The name of the hook (e.g. "help" or "menu").
 * @return
 *   TRUE if the module is both installed and enabled, and the hook is
 *   implemented in that module.
 */
function module_hook($module, $hook) {
  return function_exists($module .'_'. $hook);
139 140
}

141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174
/**
 * Invoke a hook in a particular module.
 *
 * @param $module
 *   The name of the module (without the .module extension).
 * @param $hook
 *   The name of the hook to invoke.
 * @param ...
 *   Arguments to pass to the hook implementation.
 * @return
 *   The return value of the hook implementation.
 */
function module_invoke($module, $hook, $a1 = NULL, $a2 = NULL, $a3 = NULL, $a4 = NULL) {
  $function = $module .'_'. $hook;
  if (function_exists($function)) {
    return $function($a1, $a2, $a3, $a4);
  }
}

/**
 * Invoke a hook in all enabled modules that implement it.
 *
 * @param $hook
 *   The name of the hook to invoke.
 * @param ...
 *   Arguments to pass to the hook.
 * @return
 *   An array of return values of the hook implementations. If modules return
 *   arrays from their implementations, those are merged into one array.
 */
function module_invoke_all($hook, $a1 = NULL, $a2 = NULL, $a3 = NULL, $a4 = NULL) {
  $return = array();
  foreach (module_list() as $module) {
    $result = module_invoke($module, $hook, $a1, $a2, $a3, $a4);
175
    if (is_array($result)) {
176 177
      $return = array_merge($return, $result);
    }
178 179 180
    else if (isset($result)) {
      $return[] = $result;
    }
181 182 183 184 185 186
  }

  return $return;
}

/**
Dries's avatar
 
Dries committed
187
 * @} End of "defgroup hooks".
188 189
 */

Dries's avatar
 
Dries committed
190
?>