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1 <?php 2 3 /** 4 * @file 5 * API for loading and interacting with Drupal modules. 6 */ 7 8 /** 9 * Loads all the modules that have been enabled in the system table. 10 * 11 * @param $bootstrap 12 * Whether to load only the reduced set of modules loaded in "bootstrap mode" 13 * for cached pages. See bootstrap.inc. 14 * 15 * @return 16 * If $bootstrap is NULL, return a boolean indicating whether all modules 17 * have been loaded. 18 */ 19 function module_load_all($bootstrap = FALSE) { 20 static $has_run = FALSE; 21 22 if (isset($bootstrap)) { 23 foreach (module_list(TRUE, $bootstrap) as $module) { 24 drupal_load('module', $module); 25 } 26 // $has_run will be TRUE if $bootstrap is FALSE. 27 $has_run = !$bootstrap; 28 } 29 return $has_run; 30 } 31 32 33 /** 34 * Returns a list of currently active modules. 35 * 36 * Usually, this returns a list of all enabled modules. When called early on in 37 * the bootstrap, it will return a list of vital modules only (those needed to 38 * generate cached pages). 39 * 40 * All parameters to this function are optional and should generally not be 41 * changed from their defaults. 42 * 43 * @param $refresh 44 * (optional) Whether to force the module list to be regenerated (such as 45 * after the administrator has changed the system settings). Defaults to 46 * FALSE. 47 * @param $bootstrap_refresh 48 * (optional) When $refresh is TRUE, setting $bootstrap_refresh to TRUE forces 49 * the module list to be regenerated using the reduced set of modules loaded 50 * in "bootstrap mode" for cached pages. Otherwise, setting $refresh to TRUE 51 * generates the complete list of enabled modules. 52 * @param $sort 53 * (optional) By default, modules are ordered by weight and module name. Set 54 * this option to TRUE to return a module list ordered only by module name. 55 * @param $fixed_list 56 * (optional) If an array of module names is provided, this will override the 57 * module list with the given set of modules. This will persist until the next 58 * call with $refresh set to TRUE or with a new $fixed_list passed in. This 59 * parameter is primarily intended for internal use (e.g., in install.php and 60 * update.php). 61 * 62 * @return 63 * An associative array whose keys and values are the names of the modules in 64 * the list. 65 */ 66 function module_list($refresh = FALSE, $bootstrap_refresh = FALSE, $sort = FALSE, $fixed_list = NULL) { 67 static $list = array(), $sorted_list; 68 69 if (empty($list) || $refresh || $fixed_list) { 70 $list = array(); 71 $sorted_list = NULL; 72 if ($fixed_list) { 73 foreach ($fixed_list as $name => $module) { 74 drupal_get_filename('module', $name, $module['filename']); 75 $list[$name] = $name; 76 } 77 } 78 else { 79 if ($refresh) { 80 // For the $refresh case, make sure that system_list() returns fresh 81 // data. 82 drupal_static_reset('system_list'); 83 } 84 if ($bootstrap_refresh) { 85 $list = system_list('bootstrap'); 86 } 87 else { 88 // Not using drupal_map_assoc() here as that requires common.inc. 89 $list = array_keys(system_list('module_enabled')); 90 $list = (!empty($list) ? array_combine($list, $list) : array()); 91 } 92 } 93 } 94 if ($sort) { 95 if (!isset($sorted_list)) { 96 $sorted_list = $list; 97 ksort($sorted_list); 98 } 99 return $sorted_list; 100 } 101 return $list; 102 } 103 104 /** 105 * Builds a list of bootstrap modules and enabled modules and themes. 106 * 107 * @param $type 108 * The type of list to return: 109 * - module_enabled: All enabled modules. 110 * - bootstrap: All enabled modules required for bootstrap. 111 * - theme: All themes. 112 * 113 * @return 114 * An associative array of modules or themes, keyed by name. For $type 115 * 'bootstrap', the array values equal the keys. For $type 'module_enabled' 116 * or 'theme', the array values are objects representing the respective 117 * database row, with the 'info' property already unserialized. 118 * 119 * @see module_list() 120 * @see list_themes() 121 */ 122 function system_list($type) { 123 $lists = &drupal_static(__FUNCTION__); 124 125 // For bootstrap modules, attempt to fetch the list from cache if possible. 126 // if not fetch only the required information to fire bootstrap hooks 127 // in case we are going to serve the page from cache. 128 if ($type == 'bootstrap') { 129 if (isset($lists['bootstrap'])) { 130 return $lists['bootstrap']; 131 } 132 if ($cached = cache_get('bootstrap_modules', 'cache_bootstrap')) { 133 $bootstrap_list = $cached->data; 134 } 135 else { 136 $bootstrap_list = db_query("SELECT name, filename FROM {system} WHERE status = 1 AND bootstrap = 1 AND type = 'module' ORDER BY weight ASC, name ASC")->fetchAllAssoc('name'); 137 cache_set('bootstrap_modules', $bootstrap_list, 'cache_bootstrap'); 138 } 139 // To avoid a separate database lookup for the filepath, prime the 140 // drupal_get_filename() static cache for bootstrap modules only. 141 // The rest is stored separately to keep the bootstrap module cache small. 142 foreach ($bootstrap_list as $module) { 143 drupal_get_filename('module', $module->name, $module->filename); 144 } 145 // We only return the module names here since module_list() doesn't need 146 // the filename itself. 147 $lists['bootstrap'] = array_keys($bootstrap_list); 148 } 149 // Otherwise build the list for enabled modules and themes. 150 elseif (!isset($lists['module_enabled'])) { 151 if ($cached = cache_get('system_list', 'cache_bootstrap')) { 152 $lists = $cached->data; 153 } 154 else { 155 $lists = array( 156 'module_enabled' => array(), 157 'theme' => array(), 158 'filepaths' => array(), 159 ); 160 // The module name (rather than the filename) is used as the fallback 161 // weighting in order to guarantee consistent behavior across different 162 // Drupal installations, which might have modules installed in different 163 // locations in the file system. The ordering here must also be 164 // consistent with the one used in module_implements(). 165 $result = db_query("SELECT * FROM {system} WHERE type = 'theme' OR (type = 'module' AND status = 1) ORDER BY weight ASC, name ASC"); 166 foreach ($result as $record) { 167 $record->info = unserialize($record->info); 168 // Build a list of all enabled modules. 169 if ($record->type == 'module') { 170 $lists['module_enabled'][$record->name] = $record; 171 } 172 // Build a list of themes. 173 if ($record->type == 'theme') { 174 $lists['theme'][$record->name] = $record; 175 } 176 // Build a list of filenames so drupal_get_filename can use it. 177 if ($record->status) { 178 $lists['filepaths'][] = array('type' => $record->type, 'name' => $record->name, 'filepath' => $record->filename); 179 } 180 } 181 foreach ($lists['theme'] as $key => $theme) { 182 if (!empty($theme->info['base theme'])) { 183 // Make a list of the theme's base themes. 184 require_once DRUPAL_ROOT . '/includes/theme.inc'; 185 $lists['theme'][$key]->base_themes = drupal_find_base_themes($lists['theme'], $key); 186 // Don't proceed if there was a problem with the root base theme. 187 if (!current($lists['theme'][$key]->base_themes)) { 188 continue; 189 } 190 // Determine the root base theme. 191 $base_key = key($lists['theme'][$key]->base_themes); 192 // Add to the list of sub-themes for each of the theme's base themes. 193 foreach (array_keys($lists['theme'][$key]->base_themes) as $base_theme) { 194 $lists['theme'][$base_theme]->sub_themes[$key] = $lists['theme'][$key]->info['name']; 195 } 196 // Add the base theme's theme engine info. 197 $lists['theme'][$key]->info['engine'] = isset($lists['theme'][$base_key]->info['engine']) ? $lists['theme'][$base_key]->info['engine'] : 'theme'; 198 } 199 else { 200 // A plain theme is its own engine. 201 $base_key = $key; 202 if (!isset($lists['theme'][$key]->info['engine'])) { 203 $lists['theme'][$key]->info['engine'] = 'theme'; 204 } 205 } 206 // Set the theme engine prefix. 207 $lists['theme'][$key]->prefix = ($lists['theme'][$key]->info['engine'] == 'theme') ? $base_key : $lists['theme'][$key]->info['engine']; 208 } 209 cache_set('system_list', $lists, 'cache_bootstrap'); 210 } 211 // To avoid a separate database lookup for the filepath, prime the 212 // drupal_get_filename() static cache with all enabled modules and themes. 213 foreach ($lists['filepaths'] as $item) { 214 drupal_get_filename($item['type'], $item['name'], $item['filepath']); 215 } 216 } 217 218 return $lists[$type]; 219 } 220 221 /** 222 * Resets all system_list() caches. 223 */ 224 function system_list_reset() { 225 drupal_static_reset('system_list'); 226 drupal_static_reset('system_rebuild_module_data'); 227 drupal_static_reset('list_themes'); 228 cache_clear_all('bootstrap_modules', 'cache_bootstrap'); 229 cache_clear_all('system_list', 'cache_bootstrap'); 230 } 231 232 /** 233 * Determines which modules require and are required by each module. 234 * 235 * @param $files 236 * The array of filesystem objects used to rebuild the cache. 237 * 238 * @return 239 * The same array with the new keys for each module: 240 * - requires: An array with the keys being the modules that this module 241 * requires. 242 * - required_by: An array with the keys being the modules that will not work 243 * without this module. 244 */ 245 function _module_build_dependencies($files) { 246 require_once DRUPAL_ROOT . '/includes/graph.inc'; 247 foreach ($files as $filename => $file) { 248 $graph[$file->name]['edges'] = array(); 249 if (isset($file->info['dependencies']) && is_array($file->info['dependencies'])) { 250 foreach ($file->info['dependencies'] as $dependency) { 251 $dependency_data = drupal_parse_dependency($dependency); 252 $graph[$file->name]['edges'][$dependency_data['name']] = $dependency_data; 253 } 254 } 255 } 256 drupal_depth_first_search($graph); 257 foreach ($graph as $module => $data) { 258 $files[$module]->required_by = isset($data['reverse_paths']) ? $data['reverse_paths'] : array(); 259 $files[$module]->requires = isset($data['paths']) ? $data['paths'] : array(); 260 $files[$module]->sort = $data['weight']; 261 } 262 return $files; 263 } 264 265 /** 266 * Determines whether a given module exists. 267 * 268 * @param $module 269 * The name of the module (without the .module extension). 270 * 271 * @return 272 * TRUE if the module is both installed and enabled. 273 */ 274 function module_exists($module) { 275 $list = module_list(); 276 return isset($list[$module]); 277 } 278 279 /** 280 * Loads a module's installation hooks. 281 * 282 * @param $module 283 * The name of the module (without the .module extension). 284 * 285 * @return 286 * The name of the module's install file, if successful; FALSE otherwise. 287 */ 288 function module_load_install($module) { 289 // Make sure the installation API is available 290 include_once DRUPAL_ROOT . '/includes/install.inc'; 291 292 return module_load_include('install', $module); 293 } 294 295 /** 296 * Loads a module include file. 297 * 298 * Examples: 299 * @code 300 * // Load node.admin.inc from the node module. 301 * module_load_include('inc', 'node', 'node.admin'); 302 * // Load content_types.inc from the node module. 303 * module_load_include('inc', 'node', 'content_types'); 304 * @endcode 305 * 306 * Do not use this function to load an install file, use module_load_install() 307 * instead. Do not use this function in a global context since it requires 308 * Drupal to be fully bootstrapped, use require_once DRUPAL_ROOT . '/path/file' 309 * instead. 310 * 311 * @param $type 312 * The include file's type (file extension). 313 * @param $module 314 * The module to which the include file belongs. 315 * @param $name 316 * (optional) The base file name (without the $type extension). If omitted, 317 * $module is used; i.e., resulting in "$module.$type" by default. 318 * 319 * @return 320 * The name of the included file, if successful; FALSE otherwise. 321 */ 322 function module_load_include($type, $module, $name = NULL) { 323 if (!isset($name)) { 324 $name = $module; 325 } 326 327 if (function_exists('drupal_get_path')) { 328 $file = DRUPAL_ROOT . '/' . drupal_get_path('module', $module) . "/$name.$type"; 329 if (is_file($file)) { 330 require_once $file; 331 return $file; 332 } 333 } 334 return FALSE; 335 } 336 337 /** 338 * Loads an include file for each module enabled in the {system} table. 339 */ 340 function module_load_all_includes($type, $name = NULL) { 341 $modules = module_list(); 342 foreach ($modules as $module) { 343 module_load_include($type, $module, $name); 344 } 345 } 346 347 /** 348 * Enables or installs a given list of modules. 349 * 350 * Definitions: 351 * - "Enabling" is the process of activating a module for use by Drupal. 352 * - "Disabling" is the process of deactivating a module. 353 * - "Installing" is the process of enabling it for the first time or after it 354 * has been uninstalled. 355 * - "Uninstalling" is the process of removing all traces of a module. 356 * 357 * Order of events: 358 * - Gather and add module dependencies to $module_list (if applicable). 359 * - For each module that is being enabled: 360 * - Install module schema and update system registries and caches. 361 * - If the module is being enabled for the first time or had been 362 * uninstalled, invoke hook_install() and add it to the list of installed 363 * modules. 364 * - Invoke hook_enable(). 365 * - Invoke hook_modules_installed(). 366 * - Invoke hook_modules_enabled(). 367 * 368 * @param $module_list 369 * An array of module names. 370 * @param $enable_dependencies 371 * If TRUE, dependencies will automatically be added and enabled in the 372 * correct order. This incurs a significant performance cost, so use FALSE 373 * if you know $module_list is already complete and in the correct order. 374 * 375 * @return 376 * FALSE if one or more dependencies are missing, TRUE otherwise. 377 * 378 * @see hook_install() 379 * @see hook_enable() 380 * @see hook_modules_installed() 381 * @see hook_modules_enabled() 382 */ 383 function module_enable($module_list, $enable_dependencies = TRUE) { 384 if ($enable_dependencies) { 385 // Get all module data so we can find dependencies and sort. 386 $module_data = system_rebuild_module_data(); 387 // Create an associative array with weights as values. 388 $module_list = array_flip(array_values($module_list)); 389 390 while (list($module) = each($module_list)) { 391 if (!isset($module_data[$module])) { 392 // This module is not found in the filesystem, abort. 393 return FALSE; 394 } 395 if ($module_data[$module]->status) { 396 // Skip already enabled modules. 397 unset($module_list[$module]); 398 continue; 399 } 400 $module_list[$module] = $module_data[$module]->sort; 401 402 // Add dependencies to the list, with a placeholder weight. 403 // The new modules will be processed as the while loop continues. 404 foreach (array_keys($module_data[$module]->requires) as $dependency) { 405 if (!isset($module_list[$dependency])) { 406 $module_list[$dependency] = 0; 407 } 408 } 409 } 410 411 if (!$module_list) { 412 // Nothing to do. All modules already enabled. 413 return TRUE; 414 } 415 416 // Sort the module list by pre-calculated weights. 417 arsort($module_list); 418 $module_list = array_keys($module_list); 419 } 420 421 // Required for module installation checks. 422 include_once DRUPAL_ROOT . '/includes/install.inc'; 423 424 $modules_installed = array(); 425 $modules_enabled = array(); 426 foreach ($module_list as $module) { 427 // Only process modules that are not already enabled. 428 $existing = db_query("SELECT status FROM {system} WHERE type = :type AND name = :name", array( 429 ':type' => 'module', 430 ':name' => $module)) 431 ->fetchObject(); 432 if ($existing->status == 0) { 433 // Load the module's code. 434 drupal_load('module', $module); 435 module_load_install($module); 436 437 // Update the database and module list to reflect the new module. This 438 // needs to be done first so that the module's hook implementations, 439 // hook_schema() in particular, can be called while it is being 440 // installed. 441 db_update('system') 442 ->fields(array('status' => 1)) 443 ->condition('type', 'module') 444 ->condition('name', $module) 445 ->execute(); 446 // Refresh the module list to include it. 447 system_list_reset(); 448 module_list(TRUE); 449 module_implements('', FALSE, TRUE); 450 _system_update_bootstrap_status(); 451 // Update the registry to include it. 452 registry_update(); 453 // Refresh the schema to include it. 454 drupal_get_schema(NULL, TRUE); 455 // Update the theme registry to include it. 456 drupal_theme_rebuild(); 457 // Clear entity cache. 458 entity_info_cache_clear(); 459 460 // Now install the module if necessary. 461 if (drupal_get_installed_schema_version($module, TRUE) == SCHEMA_UNINSTALLED) { 462 drupal_install_schema($module); 463 464 // Set the schema version to the number of the last update provided 465 // by the module. 466 $versions = drupal_get_schema_versions($module); 467 $version = $versions ? max($versions) : SCHEMA_INSTALLED; 468 469 // If the module has no current updates, but has some that were 470 // previously removed, set the version to the value of 471 // hook_update_last_removed(). 472 if ($last_removed = module_invoke($module, 'update_last_removed')) { 473 $version = max($version, $last_removed); 474 } 475 drupal_set_installed_schema_version($module, $version); 476 // Allow the module to perform install tasks. 477 module_invoke($module, 'install'); 478 // Record the fact that it was installed. 479 $modules_installed[] = $module; 480 watchdog('system', '%module module installed.', array('%module' => $module), WATCHDOG_INFO); 481 } 482 483 // Enable the module. 484 module_invoke($module, 'enable'); 485 486 // Record the fact that it was enabled. 487 $modules_enabled[] = $module; 488 watchdog('system', '%module module enabled.', array('%module' => $module), WATCHDOG_INFO); 489 } 490 } 491 492 // If any modules were newly installed, invoke hook_modules_installed(). 493 if (!empty($modules_installed)) { 494 module_invoke_all('modules_installed', $modules_installed); 495 } 496 497 // If any modules were newly enabled, invoke hook_modules_enabled(). 498 if (!empty($modules_enabled)) { 499 module_invoke_all('modules_enabled', $modules_enabled); 500 } 501 502 return TRUE; 503 } 504 505 /** 506 * Disables a given set of modules. 507 * 508 * @param $module_list 509 * An array of module names. 510 * @param $disable_dependents 511 * If TRUE, dependent modules will automatically be added and disabled in the 512 * correct order. This incurs a significant performance cost, so use FALSE 513 * if you know $module_list is already complete and in the correct order. 514 */ 515 function module_disable($module_list, $disable_dependents = TRUE) { 516 if ($disable_dependents) { 517 // Get all module data so we can find dependents and sort. 518 $module_data = system_rebuild_module_data(); 519 // Create an associative array with weights as values. 520 $module_list = array_flip(array_values($module_list)); 521 522 $profile = drupal_get_profile(); 523 while (list($module) = each($module_list)) { 524 if (!isset($module_data[$module]) || !$module_data[$module]->status) { 525 // This module doesn't exist or is already disabled, skip it. 526 unset($module_list[$module]); 527 continue; 528 } 529 $module_list[$module] = $module_data[$module]->sort; 530 531 // Add dependent modules to the list, with a placeholder weight. 532 // The new modules will be processed as the while loop continues. 533 foreach ($module_data[$module]->required_by as $dependent => $dependent_data) { 534 if (!isset($module_list[$dependent]) && $dependent != $profile) { 535 $module_list[$dependent] = 0; 536 } 537 } 538 } 539 540 // Sort the module list by pre-calculated weights. 541 asort($module_list); 542 $module_list = array_keys($module_list); 543 } 544 545 $invoke_modules = array(); 546 547 foreach ($module_list as $module) { 548 if (module_exists($module)) { 549 // Check if node_access table needs rebuilding. 550 if (!node_access_needs_rebuild() && module_hook($module, 'node_grants')) { 551 node_access_needs_rebuild(TRUE); 552 } 553 554 module_load_install($module); 555 module_invoke($module, 'disable'); 556 db_update('system') 557 ->fields(array('status' => 0)) 558 ->condition('type', 'module') 559 ->condition('name', $module) 560 ->execute(); 561 $invoke_modules[] = $module; 562 watchdog('system', '%module module disabled.', array('%module' => $module), WATCHDOG_INFO); 563 } 564 } 565 566 if (!empty($invoke_modules)) { 567 // Refresh the module list to exclude the disabled modules. 568 system_list_reset(); 569 module_list(TRUE); 570 module_implements('', FALSE, TRUE); 571 entity_info_cache_clear(); 572 // Invoke hook_modules_disabled before disabling modules, 573 // so we can still call module hooks to get information. 574 module_invoke_all('modules_disabled', $invoke_modules); 575 // Update the registry to remove the newly-disabled module. 576 registry_update(); 577 _system_update_bootstrap_status(); 578 // Update the theme registry to remove the newly-disabled module. 579 drupal_theme_rebuild(); 580 } 581 582 // If there remains no more node_access module, rebuilding will be 583 // straightforward, we can do it right now. 584 if (node_access_needs_rebuild() && count(module_implements('node_grants')) == 0) { 585 node_access_rebuild(); 586 } 587 } 588 589 /** 590 * @defgroup hooks Hooks 591 * @{ 592 * Allow modules to interact with the Drupal core. 593 * 594 * Drupal's module system is based on the concept of "hooks". A hook is a PHP 595 * function that is named foo_bar(), where "foo" is the name of the module 596 * (whose filename is thus foo.module) and "bar" is the name of the hook. Each 597 * hook has a defined set of parameters and a specified result type. 598 * 599 * To extend Drupal, a module need simply implement a hook. When Drupal wishes 600 * to allow intervention from modules, it determines which modules implement a 601 * hook and calls that hook in all enabled modules that implement it. 602 * 603 * The available hooks to implement are explained here in the Hooks section of 604 * the developer documentation. The string "hook" is used as a placeholder for 605 * the module name in the hook definitions. For example, if the module file is 606 * called example.module, then hook_help() as implemented by that module would 607 * be defined as example_help(). 608 * 609 * The example functions included are not part of the Drupal core, they are 610 * just models that you can modify. Only the hooks implemented within modules 611 * are executed when running Drupal. 612 * 613 * See also @link themeable the themeable group page. @endlink 614 */ 615 616 /** 617 * Determines whether a module implements a hook. 618 * 619 * @param $module 620 * The name of the module (without the .module extension). 621 * @param $hook 622 * The name of the hook (e.g. "help" or "menu"). 623 * 624 * @return 625 * TRUE if the module is both installed and enabled, and the hook is 626 * implemented in that module. 627 */ 628 function module_hook($module, $hook) { 629 $function = $module . '_' . $hook; 630 if (function_exists($function)) { 631 return TRUE; 632 } 633 // If the hook implementation does not exist, check whether it may live in an 634 // optional include file registered via hook_hook_info(). 635 $hook_info = module_hook_info(); 636 if (isset($hook_info[$hook]['group'])) { 637 module_load_include('inc', $module, $module . '.' . $hook_info[$hook]['group']); 638 if (function_exists($function)) { 639 return TRUE; 640 } 641 } 642 return FALSE; 643 } 644 645 /** 646 * Determines which modules are implementing a hook. 647 * 648 * @param $hook 649 * The name of the hook (e.g. "help" or "menu"). 650 * @param $sort 651 * By default, modules are ordered by weight and filename, settings this option 652 * to TRUE, module list will be ordered by module name. 653 * @param $reset 654 * For internal use only: Whether to force the stored list of hook 655 * implementations to be regenerated (such as after enabling a new module, 656 * before processing hook_enable). 657 * 658 * @return 659 * An array with the names of the modules which are implementing this hook. 660 * 661 * @see module_implements_write_cache() 662 */ 663 function module_implements($hook, $sort = FALSE, $reset = FALSE) { 664 // Use the advanced drupal_static() pattern, since this is called very often. 665 static $drupal_static_fast; 666 if (!isset($drupal_static_fast)) { 667 $drupal_static_fast['implementations'] = &drupal_static(__FUNCTION__); 668 } 669 $implementations = &$drupal_static_fast['implementations']; 670 671 // We maintain a persistent cache of hook implementations in addition to the 672 // static cache to avoid looping through every module and every hook on each 673 // request. Benchmarks show that the benefit of this caching outweighs the 674 // additional database hit even when using the default database caching 675 // backend and only a small number of modules are enabled. The cost of the 676 // cache_get() is more or less constant and reduced further when non-database 677 // caching backends are used, so there will be more significant gains when a 678 // large number of modules are installed or hooks invoked, since this can 679 // quickly lead to module_hook() being called several thousand times 680 // per request. 681 if ($reset) { 682 $implementations = array(); 683 cache_set('module_implements', array(), 'cache_bootstrap'); 684 drupal_static_reset('module_hook_info'); 685 drupal_static_reset('drupal_alter'); 686 cache_clear_all('hook_info', 'cache_bootstrap'); 687 return; 688 } 689 690 // Fetch implementations from cache. 691 if (empty($implementations)) { 692 $implementations = cache_get('module_implements', 'cache_bootstrap'); 693 if ($implementations === FALSE) { 694 $implementations = array(); 695 } 696 else { 697 $implementations = $implementations->data; 698 } 699 } 700 701 if (!isset($implementations[$hook])) { 702 // The hook is not cached, so ensure that whether or not it has 703 // implementations, that the cache is updated at the end of the request. 704 $implementations['#write_cache'] = TRUE; 705 $hook_info = module_hook_info(); 706 $implementations[$hook] = array(); 707 $list = module_list(FALSE, FALSE, $sort); 708 foreach ($list as $module) { 709 $include_file = isset($hook_info[$hook]['group']) && module_load_include('inc', $module, $module . '.' . $hook_info[$hook]['group']); 710 // Since module_hook() may needlessly try to load the include file again, 711 // function_exists() is used directly here. 712 if (function_exists($module . '_' . $hook)) { 713 $implementations[$hook][$module] = $include_file ? $hook_info[$hook]['group'] : FALSE; 714 } 715 } 716 // Allow modules to change the weight of specific implementations but avoid 717 // an infinite loop. 718 if ($hook != 'module_implements_alter') { 719 drupal_alter('module_implements', $implementations[$hook], $hook); 720 } 721 } 722 else { 723 foreach ($implementations[$hook] as $module => $group) { 724 // If this hook implementation is stored in a lazy-loaded file, so include 725 // that file first. 726 if ($group) { 727 module_load_include('inc', $module, "$module.$group"); 728 } 729 // It is possible that a module removed a hook implementation without the 730 // implementations cache being rebuilt yet, so we check whether the 731 // function exists on each request to avoid undefined function errors. 732 // Since module_hook() may needlessly try to load the include file again, 733 // function_exists() is used directly here. 734 if (!function_exists($module . '_' . $hook)) { 735 // Clear out the stale implementation from the cache and force a cache 736 // refresh to forget about no longer existing hook implementations. 737 unset($implementations[$hook][$module]); 738 $implementations['#write_cache'] = TRUE; 739 } 740 } 741 } 742 743 return array_keys($implementations[$hook]); 744 } 745 746 /** 747 * Retrieves a list of hooks that are declared through hook_hook_info(). 748 * 749 * @return 750 * An associative array whose keys are hook names and whose values are an 751 * associative array containing a group name. The structure of the array 752 * is the same as the return value of hook_hook_info(). 753 * 754 * @see hook_hook_info() 755 */ 756 function module_hook_info() { 757 // This function is indirectly invoked from bootstrap_invoke_all(), in which 758 // case common.inc, subsystems, and modules are not loaded yet, so it does not 759 // make sense to support hook groups resp. lazy-loaded include files prior to 760 // full bootstrap. 761 if (drupal_bootstrap(NULL, FALSE) != DRUPAL_BOOTSTRAP_FULL) { 762 return array(); 763 } 764 $hook_info = &drupal_static(__FUNCTION__); 765 766 if (!isset($hook_info)) { 767 $hook_info = array(); 768 $cache = cache_get('hook_info', 'cache_bootstrap'); 769 if ($cache === FALSE) { 770 // Rebuild the cache and save it. 771 // We can't use module_invoke_all() here or it would cause an infinite 772 // loop. 773 foreach (module_list() as $module) { 774 $function = $module . '_hook_info'; 775 if (function_exists($function)) { 776 $result = $function(); 777 if (isset($result) && is_array($result)) { 778 $hook_info = array_merge_recursive($hook_info, $result); 779 } 780 } 781 } 782 // We can't use drupal_alter() for the same reason as above. 783 foreach (module_list() as $module) { 784 $function = $module . '_hook_info_alter'; 785 if (function_exists($function)) { 786 $function($hook_info); 787 } 788 } 789 cache_set('hook_info', $hook_info, 'cache_bootstrap'); 790 } 791 else { 792 $hook_info = $cache->data; 793 } 794 } 795 796 return $hook_info; 797 } 798 799 /** 800 * Writes the hook implementation cache. 801 * 802 * @see module_implements() 803 */ 804 function module_implements_write_cache() { 805 $implementations = &drupal_static('module_implements'); 806 // Check whether we need to write the cache. We do not want to cache hooks 807 // which are only invoked on HTTP POST requests since these do not need to be 808 // optimized as tightly, and not doing so keeps the cache entry smaller. 809 if (isset($implementations['#write_cache']) && ($_SERVER['REQUEST_METHOD'] == 'GET' || $_SERVER['REQUEST_METHOD'] == 'HEAD')) { 810 unset($implementations['#write_cache']); 811 cache_set('module_implements', $implementations, 'cache_bootstrap'); 812 } 813 } 814 815 /** 816 * Invokes a hook in a particular module. 817 * 818 * @param $module 819 * The name of the module (without the .module extension). 820 * @param $hook 821 * The name of the hook to invoke. 822 * @param ... 823 * Arguments to pass to the hook implementation. 824 * 825 * @return 826 * The return value of the hook implementation. 827 */ 828 function module_invoke($module, $hook) { 829 $args = func_get_args(); 830 // Remove $module and $hook from the arguments. 831 unset($args[0], $args[1]); 832 if (module_hook($module, $hook)) { 833 return call_user_func_array($module . '_' . $hook, $args); 834 } 835 } 836 837 /** 838 * Invokes a hook in all enabled modules that implement it. 839 * 840 * @param $hook 841 * The name of the hook to invoke. 842 * @param ... 843 * Arguments to pass to the hook. 844 * 845 * @return 846 * An array of return values of the hook implementations. If modules return 847 * arrays from their implementations, those are merged into one array. 848 */ 849 function module_invoke_all($hook) { 850 $args = func_get_args(); 851 // Remove $hook from the arguments. 852 unset($args[0]); 853 $return = array(); 854 foreach (module_implements($hook) as $module) { 855 $function = $module . '_' . $hook; 856 if (function_exists($function)) { 857 $result = call_user_func_array($function, $args); 858 if (isset($result) && is_array($result)) { 859 $return = array_merge_recursive($return, $result); 860 } 861 elseif (isset($result)) { 862 $return[] = $result; 863 } 864 } 865 } 866 867 return $return; 868 } 869 870 /** 871 * @} End of "defgroup hooks". 872 */ 873 874 /** 875 * Returns an array of modules required by core. 876 */ 877 function drupal_required_modules() { 878 $files = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'modules', 'name', 0); 879 $required = array(); 880 881 // An installation profile is required and one must always be loaded. 882 $required[] = drupal_get_profile(); 883 884 foreach ($files as $name => $file) { 885 $info = drupal_parse_info_file($file->uri); 886 if (!empty($info) && !empty($info['required']) && $info['required']) { 887 $required[] = $name; 888 } 889 } 890 891 return $required; 892 } 893 894 /** 895 * Passes alterable variables to specific hook_TYPE_alter() implementations. 896 * 897 * This dispatch function hands off the passed-in variables to type-specific 898 * hook_TYPE_alter() implementations in modules. It ensures a consistent 899 * interface for all altering operations. 900 * 901 * A maximum of 2 alterable arguments is supported. In case more arguments need 902 * to be passed and alterable, modules provide additional variables assigned by 903 * reference in the last $context argument: 904 * @code 905 * $context = array( 906 * 'alterable' => &$alterable, 907 * 'unalterable' => $unalterable, 908 * 'foo' => 'bar', 909 * ); 910 * drupal_alter('mymodule_data', $alterable1, $alterable2, $context); 911 * @endcode 912 * 913 * Note that objects are always passed by reference in PHP5. If it is absolutely 914 * required that no implementation alters a passed object in $context, then an 915 * object needs to be cloned: 916 * @code 917 * $context = array( 918 * 'unalterable_object' => clone $object, 919 * ); 920 * drupal_alter('mymodule_data', $data, $context); 921 * @endcode 922 * 923 * @param $type 924 * A string describing the type of the alterable $data. 'form', 'links', 925 * 'node_content', and so on are several examples. Alternatively can be an 926 * array, in which case hook_TYPE_alter() is invoked for each value in the 927 * array, ordered first by module, and then for each module, in the order of 928 * values in $type. For example, when Form API is using drupal_alter() to 929 * execute both hook_form_alter() and hook_form_FORM_ID_alter() 930 * implementations, it passes array('form', 'form_' . $form_id) for $type. 931 * @param $data 932 * The variable that will be passed to hook_TYPE_alter() implementations to be 933 * altered. The type of this variable depends on the value of the $type 934 * argument. For example, when altering a 'form', $data will be a structured 935 * array. When altering a 'profile', $data will be an object. 936 * @param $context1 937 * (optional) An additional variable that is passed by reference. 938 * @param $context2 939 * (optional) An additional variable that is passed by reference. If more 940 * context needs to be provided to implementations, then this should be an 941 * associative array as described above. 942 */ 943 function drupal_alter($type, &$data, &$context1 = NULL, &$context2 = NULL) { 944 // Use the advanced drupal_static() pattern, since this is called very often. 945 static $drupal_static_fast; 946 if (!isset($drupal_static_fast)) { 947 $drupal_static_fast['functions'] = &drupal_static(__FUNCTION__); 948 } 949 $functions = &$drupal_static_fast['functions']; 950 951 // Most of the time, $type is passed as a string, so for performance, 952 // normalize it to that. When passed as an array, usually the first item in 953 // the array is a generic type, and additional items in the array are more 954 // specific variants of it, as in the case of array('form', 'form_FORM_ID'). 955 if (is_array($type)) { 956 $cid = implode(',', $type); 957 $extra_types = $type; 958 $type = array_shift($extra_types); 959 // Allow if statements in this function to use the faster isset() rather 960 // than !empty() both when $type is passed as a string, or as an array with 961 // one item. 962 if (empty($extra_types)) { 963 unset($extra_types); 964 } 965 } 966 else { 967 $cid = $type; 968 } 969 970 // Some alter hooks are invoked many times per page request, so statically 971 // cache the list of functions to call, and on subsequent calls, iterate 972 // through them quickly. 973 if (!isset($functions[$cid])) { 974 $functions[$cid] = array(); 975 $hook = $type . '_alter'; 976 $modules = module_implements($hook); 977 if (!isset($extra_types)) { 978 // For the more common case of a single hook, we do not need to call 979 // function_exists(), since module_implements() returns only modules with 980 // implementations. 981 foreach ($modules as $module) { 982 $functions[$cid][] = $module . '_' . $hook; 983 } 984 } 985 else { 986 // For multiple hooks, we need $modules to contain every module that 987 // implements at least one of them. 988 $extra_modules = array(); 989 foreach ($extra_types as $extra_type) { 990 $extra_modules = array_merge($extra_modules, module_implements($extra_type . '_alter')); 991 } 992 // If any modules implement one of the extra hooks that do not implement 993 // the primary hook, we need to add them to the $modules array in their 994 // appropriate order. module_implements() can only return ordered 995 // implementations of a single hook. To get the ordered implementations 996 // of multiple hooks, we mimic the module_implements() logic of first 997 // ordering by module_list(), and then calling 998 // drupal_alter('module_implements'). 999 if (array_diff($extra_modules, $modules)) { 1000 // Merge the arrays and order by module_list(). 1001 $modules = array_intersect(module_list(), array_merge($modules, $extra_modules)); 1002 // Since module_implements() already took care of loading the necessary 1003 // include files, we can safely pass FALSE for the array values. 1004 $implementations = array_fill_keys($modules, FALSE); 1005 // Let modules adjust the order solely based on the primary hook. This 1006 // ensures the same module order regardless of whether this if block 1007 // runs. Calling drupal_alter() recursively in this way does not result 1008 // in an infinite loop, because this call is for a single $type, so we 1009 // won't end up in this code block again. 1010 drupal_alter('module_implements', $implementations, $hook); 1011 $modules = array_keys($implementations); 1012 } 1013 foreach ($modules as $module) { 1014 // Since $modules is a merged array, for any given module, we do not 1015 // know whether it has any particular implementation, so we need a 1016 // function_exists(). 1017 $function = $module . '_' . $hook; 1018 if (function_exists($function)) { 1019 $functions[$cid][] = $function; 1020 } 1021 foreach ($extra_types as $extra_type) { 1022 $function = $module . '_' . $extra_type . '_alter'; 1023 if (function_exists($function)) { 1024 $functions[$cid][] = $function; 1025 } 1026 } 1027 } 1028 } 1029 // Allow the theme to alter variables after the theme system has been 1030 // initialized. 1031 global $theme, $base_theme_info; 1032 if (isset($theme)) { 1033 $theme_keys = array(); 1034 foreach ($base_theme_info as $base) { 1035 $theme_keys[] = $base->name; 1036 } 1037 $theme_keys[] = $theme; 1038 foreach ($theme_keys as $theme_key) { 1039 $function = $theme_key . '_' . $hook; 1040 if (function_exists($function)) { 1041 $functions[$cid][] = $function; 1042 } 1043 if (isset($extra_types)) { 1044 foreach ($extra_types as $extra_type) { 1045 $function = $theme_key . '_' . $extra_type . '_alter'; 1046 if (function_exists($function)) { 1047 $functions[$cid][] = $function; 1048 } 1049 } 1050 } 1051 } 1052 } 1053 } 1054 1055 foreach ($functions[$cid] as $function) { 1056 $function($data, $context1, $context2); 1057 } 1058 }
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