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<?php
// $Id: module.inc,v 1.115 2007/12/27 12:31:05 goba Exp $
/**
* @file
* API for loading and interacting with Drupal modules.
*/
/**
* Load all the modules that have been enabled in the system table.
*/
function module_load_all() {
foreach (module_list(TRUE, FALSE) as $module) {
drupal_load('module', $module);
}
}
/**
* Call a function repeatedly with each module in turn as an argument.
*/
function module_iterate($function, $argument = '') {
foreach (module_list() as $name) {
$function($name, $argument);
}
}
/**
* Collect a list of all loaded modules. During the bootstrap, return only
* vital modules. See bootstrap.inc
*
* @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.
* @param $sort
* By default, modules are ordered by weight and filename, settings this option
* to TRUE, module list will be ordered by module name.
* @param $fixed_list
* (Optional) Override the module list with the given modules. Stays until the
* next call with $refresh = TRUE.
* @return
* An associative array whose keys and values are the names of all loaded
* modules.
*/
function module_list($refresh = FALSE, $bootstrap = TRUE, $sort = FALSE, $fixed_list = NULL) {
static $list, $sorted_list;
if ($refresh || $fixed_list) {
unset($sorted_list);
$list = array();
if ($fixed_list) {
foreach ($fixed_list as $name => $module) {
drupal_get_filename('module', $name, $module['filename']);
$list[$name] = $name;
}
}
else {
if ($bootstrap) {
$result = db_query("SELECT name, filename, throttle FROM {system} WHERE type = 'module' AND status = 1 AND bootstrap = 1 ORDER BY weight ASC, filename ASC");
}
else {
$result = db_query("SELECT name, filename, throttle FROM {system} WHERE type = 'module' AND status = 1 ORDER BY weight ASC, filename ASC");
}
while ($module = db_fetch_object($result)) {
if (file_exists($module->filename)) {
// 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.
$throttle = ($module->throttle && variable_get('throttle_level', 0) > 0);
if (!$throttle) {
drupal_get_filename('module', $module->name, $module->filename);
$list[$module->name] = $module->name;
}
}
}
}
}
if ($sort) {
if (!isset($sorted_list)) {
$sorted_list = $list;
ksort($sorted_list);
}
return $sorted_list;
}
return $list;
}
/**
* Rebuild the database cache of module files.
*
* @return
* The array of filesystem objects used to rebuild the cache.
*/
function module_rebuild_cache() {
// Get current list of modules
$files = drupal_system_listing('\.module$', 'modules', 'name', 0);
// Extract current files from database.
system_get_files_database($files, 'module');
ksort($files);
// Set defaults for module info
$defaults = array(
'dependencies' => array(),
'dependents' => array(),
'description' => '',
'version' => NULL,
'php' => DRUPAL_MINIMUM_PHP,
);
foreach ($files as $filename => $file) {
// Look for the info file.
$file->info = drupal_parse_info_file(dirname($file->filename) .'/'. $file->name .'.info');
// Skip modules that don't provide info.
if (empty($file->info)) {
unset($files[$filename]);
continue;
}
// Merge in defaults and save.
$files[$filename]->info = $file->info + $defaults;
// Invoke hook_system_info_alter() to give installed modules a chance to
// modify the data in the .info files if necessary.
drupal_alter('system_info', $files[$filename]->info, $files[$filename]);
// Log the critical hooks implemented by this module.
$bootstrap = 0;
foreach (bootstrap_hooks() as $hook) {
if (module_hook($file->name, $hook)) {
$bootstrap = 1;
break;
}
}
// Update the contents of the system table:
if (isset($file->status) || (isset($file->old_filename) && $file->old_filename != $file->filename)) {
db_query("UPDATE {system} SET info = '%s', name = '%s', filename = '%s', bootstrap = %d WHERE filename = '%s'", serialize($files[$filename]->info), $file->name, $file->filename, $bootstrap, $file->old_filename);
}
else {
// This is a new module.
$files[$filename]->status = 0;
$files[$filename]->throttle = 0;
db_query("INSERT INTO {system} (name, info, type, filename, status, throttle, bootstrap) VALUES ('%s', '%s', '%s', '%s', %d, %d, %d)", $file->name, serialize($files[$filename]->info), 'module', $file->filename, 0, 0, $bootstrap);
}
}
$files = _module_build_dependencies($files);
return $files;
}
/**
* Find dependencies any level deep and fill in dependents information too.
*
* If module A depends on B which in turn depends on C then this function will
* add C to the list of modules A depends on. This will be repeated until
* module A has a list of all modules it depends on. If it depends on itself,
* called a circular dependency, that's marked by adding a nonexistent module,
* called -circular- to this list of modules. Because this does not exist,
* it'll be impossible to switch module A on.
*
* Also we fill in a dependents array in $file->info. Using the names above,
* the dependents array of module B lists A.
*
* @param $files
* The array of filesystem objects used to rebuild the cache.
* @return
* The same array with dependencies and dependents added where applicable.
*/
function _module_build_dependencies($files) {
do {
$new_dependency = FALSE;
foreach ($files as $filename => $file) {
// We will modify this object (module A, see doxygen for module A, B, C).
$file = &$files[$filename];
if (isset($file->info['dependencies']) && is_array($file->info['dependencies'])) {
foreach ($file->info['dependencies'] as $dependency_name) {
// This is a nonexistent module.
if ($dependency_name == '-circular-' || !isset($files[$dependency_name])) {
continue;
}
// $dependency_name is module B (again, see doxygen).
$files[$dependency_name]->info['dependents'][$filename] = $filename;
$dependency = $files[$dependency_name];
if (isset($dependency->info['dependencies']) && is_array($dependency->info['dependencies'])) {
// Let's find possible C modules.
foreach ($dependency->info['dependencies'] as $candidate) {
if (array_search($candidate, $file->info['dependencies']) === FALSE) {
// Is this a circular dependency?
if ($candidate == $filename) {
// As a module name can not contain dashes, this makes
// impossible to switch on the module.
$candidate = '-circular-';
// Do not display the message or add -circular- more than once.
if (array_search($candidate, $file->info['dependencies']) !== FALSE) {
continue;
}
drupal_set_message(t('%module is part of a circular dependency. This is not supported and you will not be able to switch it on.', array('%module' => $file->info['name'])), 'error');
}
else {
// We added a new dependency to module A. The next loop will
// be able to use this as "B module" thus finding even
// deeper dependencies.
$new_dependency = TRUE;
}
$file->info['dependencies'][] = $candidate;
}
}
}
}
}
// Don't forget to break the reference.
unset($file);
}
} while ($new_dependency);
return $files;
}
/**
* Determine whether a given module exists.
*
* @param $module
* The name of the module (without the .module extension).
* @return
* TRUE if the module is both installed and enabled.
*/
function module_exists($module) {
$list = module_list();
return array_key_exists($module, $list);
}
/**
* Load a module's installation hooks.
*/
function module_load_install($module) {
// Make sure the installation API is available
include_once './includes/install.inc';
module_load_include('install', $module);
}
/**
* Load a module include file.
*
* @param $type
* The include file's type (file extension).
* @param $module
* The module to which the include file belongs.
* @param $name
* Optionally, specify the file name. If not set, the module's name is used.
*/
function module_load_include($type, $module, $name = NULL) {
if (empty($name)) {
$name = $module;
}
$file = './'. drupal_get_path('module', $module) ."/$name.$type";
if (is_file($file)) {
require_once $file;
}
else {
return FALSE;
}
}
/**
* Load an include file for each of the modules that have been enabled in
* the system table.
*/
function module_load_all_includes($type, $name = NULL) {
$modules = module_list();
foreach ($modules as $module) {
module_load_include($type, $module, $name);
}
}
/**
* Enable a given list of modules.
*
* @param $module_list
* An array of module names.
*/
function module_enable($module_list) {
$invoke_modules = array();
foreach ($module_list as $module) {
$existing = db_fetch_object(db_query("SELECT status FROM {system} WHERE type = '%s' AND name = '%s'", 'module', $module));
if ($existing->status == 0) {
module_load_install($module);
db_query("UPDATE {system} SET status = %d, throttle = %d WHERE type = '%s' AND name = '%s'", 1, 0, 'module', $module);
drupal_load('module', $module);
$invoke_modules[] = $module;
}
}
if (!empty($invoke_modules)) {
// Refresh the module list to include the new enabled module.
module_list(TRUE, FALSE);
// Force to regenerate the stored list of hook implementations.
module_implements('', FALSE, TRUE);
}
foreach ($invoke_modules as $module) {
module_invoke($module, 'enable');
// Check if node_access table needs rebuilding.
// We check for the existence of node_access_needs_rebuild() since
// at install time, module_enable() could be called while node.module
// is not enabled yet.
if (function_exists('node_access_needs_rebuild') && !node_access_needs_rebuild() && module_hook($module, 'node_grants')) {
node_access_needs_rebuild(TRUE);
}
}
}
/**
* Disable a given set of modules.
*
* @param $module_list
* An array of module names.
*/
function module_disable($module_list) {
$invoke_modules = array();
foreach ($module_list as $module) {
if (module_exists($module)) {
// Check if node_access table needs rebuilding.
if (!node_access_needs_rebuild() && module_hook($module, 'node_grants')) {
node_access_needs_rebuild(TRUE);
}
module_load_install($module);
module_invoke($module, 'disable');
db_query("UPDATE {system} SET status = %d, throttle = %d WHERE type = '%s' AND name = '%s'", 0, 0, 'module', $module);
$invoke_modules[] = $module;
}
}
if (!empty($invoke_modules)) {
// Refresh the module list to exclude the disabled modules.
module_list(TRUE, FALSE);
// Force to regenerate the stored list of hook implementations.
module_implements('', FALSE, TRUE);
}
// If there remains no more node_access module, rebuilding will be
// straightforward, we can do it right now.
if (node_access_needs_rebuild() && count(module_implements('node_grants')) == 0) {
node_access_rebuild();
}
}
/**
* @defgroup hooks Hooks
* @{
* Allow modules to interact with the Drupal core.
*
* 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);
}
/**
* Determine which modules are implementing a hook.
*
* @param $hook
* The name of the hook (e.g. "help" or "menu").
* @param $sort
* By default, modules are ordered by weight and filename, settings this option
* to TRUE, module list will be ordered by module name.
* @param $refresh
* For internal use only: Whether to force the stored list of hook
* implementations to be regenerated (such as after enabling a new module,
* before processing hook_enable).
* @return
* An array with the names of the modules which are implementing this hook.
*/
function module_implements($hook, $sort = FALSE, $refresh = FALSE) {
static $implementations;
if ($refresh) {
$implementations = array();
return;
}
if (!isset($implementations[$hook])) {
$implementations[$hook] = array();
$list = module_list(FALSE, TRUE, $sort);
foreach ($list as $module) {
if (module_hook($module, $hook)) {
$implementations[$hook][] = $module;
}
}
}
// 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];
}
/**
* 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() {
$args = func_get_args();
$module = $args[0];
$hook = $args[1];
unset($args[0], $args[1]);
$function = $module .'_'. $hook;
if (module_hook($module, $hook)) {
return call_user_func_array($function, $args);
}
}
/**
* 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() {
$args = func_get_args();
$hook = $args[0];
unset($args[0]);
$return = array();
foreach (module_implements($hook) as $module) {
$function = $module .'_'. $hook;
$result = call_user_func_array($function, $args);
if (isset($result) && is_array($result)) {
$return = array_merge_recursive($return, $result);
}
else if (isset($result)) {
$return[] = $result;
}
}
return $return;
}
/**
* @} End of "defgroup hooks".
*/
/**
* Array of modules required by core.
*/
function drupal_required_modules() {
return array('block', 'filter', 'node', 'system', 'user');
}
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