module.inc 6.2 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
/**
 * Initialize all modules.
 */
function module_init() {
13
14
15
16
  // Load all the modules that have been enabled in the system table.
  foreach (module_list(TRUE, FALSE) as $module) {
    drupal_load('module', $module);
  }
17
18
19
  module_invoke_all('init');
}

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
 * Collect a list of all loaded modules. During the bootstrap, return only
 * vital modules. See bootstrap.inc
32
33
34
35
36
 *
 * @param $refresh
 *   Whether to force the module list to be regenerated (such as after the
 *   administrator has changed the system settings).
 * @param $bootstrap
37
38
 *   Whether to return the reduced set of modules loaded in "bootstrap mode"
 *   for cached pages. See bootstrap.inc.
39
40
41
42
 * @return
 *   An associative array whose keys and values are the names of all loaded
 *   modules.
 */
43
function module_list($refresh = FALSE, $bootstrap = TRUE) {
44
45
  static $list;

Dries's avatar
   
Dries committed
46
  if ($refresh) {
Dries's avatar
Dries committed
47
    $list = array();
Dries's avatar
   
Dries committed
48
49
  }

50
  if (!$list) {
51
    $list = array('filter' => 'filter', 'node' => 'node', 'system' => 'system', 'user' => 'user', 'watchdog' => 'watchdog');
52
    if ($bootstrap) {
53
      $result = db_query("SELECT name, filename, throttle, bootstrap FROM {system} WHERE type = 'module' AND status = 1 AND bootstrap = 1 ORDER BY weight ASC, filename ASC");
54
55
    }
    else {
56
      $result = db_query("SELECT name, filename, throttle, bootstrap FROM {system} WHERE type = 'module' AND status = 1 ORDER BY weight ASC, filename ASC");
57
    }
58
    while ($module = db_fetch_object($result)) {
Dries's avatar
   
Dries committed
59
      if (file_exists($module->filename)) {
60
61
62
        // 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.
63
        $throttle = ($module->throttle && variable_get('throttle_level', 0) > 0);
64
        if (!$throttle) {
Dries's avatar
Dries committed
65
          drupal_get_filename('module', $module->name, $module->filename);
Dries's avatar
   
Dries committed
66
67
          $list[$module->name] = $module->name;
        }
68
      }
69
70
71
72
73
    }
  }
  return $list;
}

74
75
76
77
78
79
80
81
82
/**
 * 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) {
83
  $list = module_list();
84
  return array_key_exists($module, $list);
85
86
}

87
88
/**
 * @defgroup hooks Hooks
Dries's avatar
   
Dries committed
89
90
 * @{
 * Allow modules to interact with the Drupal core.
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
 *
 * 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);
121
122
}

Dries's avatar
   
Dries committed
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/**
 * Determine which modules are implementing a hook.
 *
 * @param $hook
 *   The name of the hook (e.g. "help" or "menu").
 * @return
 *   An array with the names of the modules which are implementing this hook.
 */
function module_implements($hook) {
  static $implementations;

  if (!isset($implementations[$hook])) {
    $implementations[$hook] = array();
    $list = module_list();
    foreach ($list as $module) {
      if (module_hook($module, $hook)) {
        $implementations[$hook][] = $module;
      }
    }
  }

144
145
146
147
148
149
150
  // The explicit cast forces a copy to be made.  This is needed because
  // $implementations[$hook] is only a reference to an element of
  // $implementations and if there are nested foreaches (due to nested node
  // API calls, for example), they would both manipulate the same array's
  // references, which causes some modules' hooks not to be called.
  // See also http://www.zend.com/zend/art/ref-count.php.
  return (array)$implementations[$hook];
Dries's avatar
   
Dries committed
151
152
}

153
154
155
156
157
158
159
160
161
162
163
164
/**
 * 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.
 */
165
166
167
168
function module_invoke() {
  $args = func_get_args();
  $module = array_shift($args);
  $hook = array_shift($args);
169
  $function = $module .'_'. $hook;
170
171
  if (module_hook($module, $hook)) {
    return call_user_func_array($function, $args);
172
173
174
175
176
177
178
179
180
181
182
183
184
  }
}
/**
 * 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.
 */
185
186
187
function module_invoke_all() {
  $args = func_get_args();
  $hook = array_shift($args);
188
  $return = array();
189
190
191
  foreach (module_implements($hook) as $module) {
    $function = $module .'_'. $hook;
    $result = call_user_func_array($function, $args);
192
    if (isset($result) && is_array($result)) {
193
194
      $return = array_merge($return, $result);
    }
195
196
197
    else if (isset($result)) {
      $return[] = $result;
    }
198
199
200
201
202
203
  }

  return $return;
}

/**
Dries's avatar
   
Dries committed
204
 * @} End of "defgroup hooks".
205
206
 */

207