lib/outputrequirementslib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Library functions to facilitate the use of JavaScript in Moodle.
  19  *
  20  * Note: you can find history of this file in lib/ajax/ajaxlib.php
  21  *
  22  * @copyright 2009 Tim Hunt, 2010 Petr Skoda
  23  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  * @package core
  25  * @category output
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die();
  29
  30 /**
  31  * This class tracks all the things that are needed by the current page.
  32  *
  33  * Normally, the only instance of this  class you will need to work with is the
  34  * one accessible via $PAGE->requires.
  35  *
  36  * Typical usage would be
  37  * <pre>
  38  *     $PAGE->requires->js_call_amd('mod_forum/view', 'init');
  39  * </pre>
  40  *
  41  * It also supports obsoleted coding style with/without YUI3 modules.
  42  * <pre>
  43  *     $PAGE->requires->js_init_call('M.mod_forum.init_view');
  44  *     $PAGE->requires->css('/mod/mymod/userstyles.php?id='.$id); // not overridable via themes!
  45  *     $PAGE->requires->js('/mod/mymod/script.js');
  46  *     $PAGE->requires->js('/mod/mymod/small_but_urgent.js', true);
  47  *     $PAGE->requires->js_function_call('init_mymod', array($data), true);
  48  * </pre>
  49  *
  50  * There are some natural restrictions on some methods. For example, {@link css()}
  51  * can only be called before the <head> tag is output. See the comments on the
  52  * individual methods for details.
  53  *
  54  * @copyright 2009 Tim Hunt, 2010 Petr Skoda
  55  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  56  * @since Moodle 2.0
  57  * @package core
  58  * @category output
  59  */
  60 class page_requirements_manager {
  61
  62     /**
  63      * @var array List of string available from JS
  64      */
  65     protected $stringsforjs = array();
  66
  67     /**
  68      * @var array List of get_string $a parameters - used for validation only.
  69      */
  70     protected $stringsforjs_as = array();
  71
  72     /**
  73      * @var array List of JS variables to be initialised
  74      */
  75     protected $jsinitvariables = array('head'=>array(), 'footer'=>array());
  76
  77     /**
  78      * @var array Included JS scripts
  79      */
  80     protected $jsincludes = array('head'=>array(), 'footer'=>array());
  81
  82     /**
  83      * @var array Inline scripts using RequireJS module loading.
  84      */
  85     protected $amdjscode = array('');
  86
  87     /**
  88      * @var array List of needed function calls
  89      */
  90     protected $jscalls = array('normal'=>array(), 'ondomready'=>array());
  91
  92     /**
  93      * @var array List of skip links, those are needed for accessibility reasons
  94      */
  95     protected $skiplinks = array();
  96
  97     /**
  98      * @var array Javascript code used for initialisation of page, it should
  99      * be relatively small
 100      */
 101     protected $jsinitcode = array();
 102
 103     /**
 104      * @var array of moodle_url Theme sheets, initialised only from core_renderer
 105      */
 106     protected $cssthemeurls = array();
 107
 108     /**
 109      * @var array of moodle_url List of custom theme sheets, these are strongly discouraged!
 110      * Useful mostly only for CSS submitted by teachers that is not part of the theme.
 111      */
 112     protected $cssurls = array();
 113
 114     /**
 115      * @var array List of requested event handlers
 116      */
 117     protected $eventhandlers = array();
 118
 119     /**
 120      * @var array Extra modules
 121      */
 122     protected $extramodules = array();
 123
 124     /**
 125      * @var array trackes the names of bits of HTML that are only required once
 126      * per page. See {@link has_one_time_item_been_created()},
 127      * {@link set_one_time_item_created()} and {@link should_create_one_time_item_now()}.
 128      */
 129     protected $onetimeitemsoutput = array();
 130
 131     /**
 132      * @var bool Flag indicated head stuff already printed
 133      */
 134     protected $headdone = false;
 135
 136     /**
 137      * @var bool Flag indicating top of body already printed
 138      */
 139     protected $topofbodydone = false;
 140
 141     /**
 142      * @var stdClass YUI PHPLoader instance responsible for YUI3 loading from PHP only
 143      */
 144     protected $yui3loader;
 145
 146     /**
 147      * @var YUI_config default YUI loader configuration
 148      */
 149     protected $YUI_config;
 150
 151     /**
 152      * @var array $yuicssmodules
 153      */
 154     protected $yuicssmodules = array();
 155
 156     /**
 157      * @var array Some config vars exposed in JS, please no secret stuff there
 158      */
 159     protected $M_cfg;
 160
 161     /**
 162      * @var array list of requested jQuery plugins
 163      */
 164     protected $jqueryplugins = array();
 165
 166     /**
 167      * @var array list of jQuery plugin overrides
 168      */
 169     protected $jquerypluginoverrides = array();
 170
 171     /**
 172      * Page requirements constructor.
 173      */
 174     public function __construct() {
 175         global $CFG;
 176
 177         // You may need to set up URL rewrite rule because oversized URLs might not be allowed by web server.
 178         $sep = empty($CFG->yuislasharguments) ? '?' : '/';
 179
 180         $this->yui3loader = new stdClass();
 181         $this->YUI_config = new YUI_config();
 182
 183         if (is_https() && !empty($CFG->useexternalyui)) {
 184             // On HTTPS sites all JS must be loaded from https sites,
 185             // YUI CDN does not support https yet, sorry.
 186             $CFG->useexternalyui = 0;
 187         }
 188
 189         // Set up some loader options.
 190         $this->yui3loader->local_base = $CFG->wwwroot . '/lib/yuilib/'. $CFG->yui3version . '/';
 191         $this->yui3loader->local_comboBase = $CFG->wwwroot . '/theme/yui_combo.php'.$sep;
 192
 193         if (!empty($CFG->useexternalyui)) {
 194             $this->yui3loader->base = 'http://yui.yahooapis.com/' . $CFG->yui3version . '/';
 195             $this->yui3loader->comboBase = 'http://yui.yahooapis.com/combo?';
 196         } else {
 197             $this->yui3loader->base = $this->yui3loader->local_base;
 198             $this->yui3loader->comboBase = $this->yui3loader->local_comboBase;
 199         }
 200
 201         // Enable combo loader? This significantly helps with caching and performance!
 202         $this->yui3loader->combine = !empty($CFG->yuicomboloading);
 203
 204         $jsrev = $this->get_jsrev();
 205
 206         // Set up JS YUI loader helper object.
 207         $this->YUI_config->base         = $this->yui3loader->base;
 208         $this->YUI_config->comboBase    = $this->yui3loader->comboBase;
 209         $this->YUI_config->combine      = $this->yui3loader->combine;
 210
 211         // If we've had to patch any YUI modules between releases, we must override the YUI configuration to include them.
 212         // For important information on patching YUI modules, please see http://docs.moodle.org/dev/YUI/Patching.
 213         if (!empty($CFG->yuipatchedmodules) && !empty($CFG->yuipatchlevel)) {
 214             $this->YUI_config->define_patched_core_modules($this->yui3loader->local_comboBase,
 215                     $CFG->yui3version,
 216                     $CFG->yuipatchlevel,
 217                     $CFG->yuipatchedmodules);
 218         }
 219
 220         $configname = $this->YUI_config->set_config_source('lib/yui/config/yui2.js');
 221         $this->YUI_config->add_group('yui2', array(
 222             // Loader configuration for our 2in3, for now ignores $CFG->useexternalyui.
 223             'base' => $CFG->wwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 224             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 225             'combine' => $this->yui3loader->combine,
 226             'ext' => false,
 227             'root' => '2in3/' . $CFG->yui2version .'/build/',
 228             'patterns' => array(
 229                 'yui2-' => array(
 230                     'group' => 'yui2',
 231                     'configFn' => $configname,
 232                 )
 233             )
 234         ));
 235         $configname = $this->YUI_config->set_config_source('lib/yui/config/moodle.js');
 236         $this->YUI_config->add_group('moodle', array(
 237             'name' => 'moodle',
 238             'base' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep . 'm/' . $jsrev . '/',
 239             'combine' => $this->yui3loader->combine,
 240             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 241             'ext' => false,
 242             'root' => 'm/'.$jsrev.'/', // Add the rev to the root path so that we can control caching.
 243             'patterns' => array(
 244                 'moodle-' => array(
 245                     'group' => 'moodle',
 246                     'configFn' => $configname,
 247                 )
 248             )
 249         ));
 250
 251         $this->YUI_config->add_group('gallery', array(
 252             'name' => 'gallery',
 253             'base' => $CFG->wwwroot . '/lib/yuilib/gallery/',
 254             'combine' => $this->yui3loader->combine,
 255             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep,
 256             'ext' => false,
 257             'root' => 'gallery/' . $jsrev . '/',
 258             'patterns' => array(
 259                 'gallery-' => array(
 260                     'group' => 'gallery',
 261                 )
 262             )
 263         ));
 264
 265         // Set some more loader options applying to groups too.
 266         if ($CFG->debugdeveloper) {
 267             // When debugging is enabled, we want to load the non-minified (RAW) versions of YUI library modules rather
 268             // than the DEBUG versions as these generally generate too much logging for our purposes.
 269             // However we do want the DEBUG versions of our Moodle-specific modules.
 270             // To debug a YUI-specific issue, change the yui3loader->filter value to DEBUG.
 271             $this->YUI_config->filter = 'RAW';
 272             $this->YUI_config->groups['moodle']['filter'] = 'DEBUG';
 273
 274             // We use the yui3loader->filter setting when writing the YUI3 seed scripts into the header.
 275             $this->yui3loader->filter = $this->YUI_config->filter;
 276             $this->YUI_config->debug = true;
 277         } else {
 278             $this->yui3loader->filter = null;
 279             $this->YUI_config->groups['moodle']['filter'] = null;
 280             $this->YUI_config->debug = false;
 281         }
 282
 283         // Include the YUI config log filters.
 284         if (!empty($CFG->yuilogexclude) && is_array($CFG->yuilogexclude)) {
 285             $this->YUI_config->logExclude = $CFG->yuilogexclude;
 286         }
 287         if (!empty($CFG->yuiloginclude) && is_array($CFG->yuiloginclude)) {
 288             $this->YUI_config->logInclude = $CFG->yuiloginclude;
 289         }
 290         if (!empty($CFG->yuiloglevel)) {
 291             $this->YUI_config->logLevel = $CFG->yuiloglevel;
 292         }
 293
 294         // Add the moodle group's module data.
 295         $this->YUI_config->add_moodle_metadata();
 296
 297         // Every page should include definition of following modules.
 298         $this->js_module($this->find_module('core_filepicker'));
 299         $this->js_module($this->find_module('core_comment'));
 300     }
 301
 302     /**
 303      * Return the safe config values that get set for javascript in "M.cfg".
 304      *
 305      * @since 2.9
 306      * @return array List of safe config values that are available to javascript.
 307      */
 308     public function get_config_for_javascript(moodle_page $page, renderer_base $renderer) {
 309         global $CFG;
 310
 311         if (empty($this->M_cfg)) {
 312
 313             $iconsystem = \core\output\icon_system::instance();
 314
 315             // It is possible that the $page->context is null, so we can't use $page->context->id.
 316             $contextid = null;
 317             if (!is_null($page->context)) {
 318                 $contextid = $page->context->id;
 319             }
 320
 321             $this->M_cfg = array(
 322                 'wwwroot'             => $CFG->wwwroot,
 323                 'sesskey'             => sesskey(),
 324                 'themerev'            => theme_get_revision(),
 325                 'slasharguments'      => (int)(!empty($CFG->slasharguments)),
 326                 'theme'               => $page->theme->name,
 327                 'iconsystemmodule'    => $iconsystem->get_amd_name(),
 328                 'jsrev'               => $this->get_jsrev(),
 329                 'admin'               => $CFG->admin,
 330                 'svgicons'            => $page->theme->use_svg_icons(),
 331                 'usertimezone'        => usertimezone(),
 332                 'contextid'           => $contextid,
 333             );
 334             if ($CFG->debugdeveloper) {
 335                 $this->M_cfg['developerdebug'] = true;
 336             }
 337             if (defined('BEHAT_SITE_RUNNING')) {
 338                 $this->M_cfg['behatsiterunning'] = true;
 339             }
 340
 341         }
 342         return $this->M_cfg;
 343     }
 344
 345     /**
 346      * Initialise with the bits of JavaScript that every Moodle page should have.
 347      *
 348      * @param moodle_page $page
 349      * @param core_renderer $renderer
 350      */
 351     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 352         global $CFG;
 353
 354         // Init the js config.
 355         $this->get_config_for_javascript($page, $renderer);
 356
 357         // Accessibility stuff.
 358         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 359
 360         // Add strings used on many pages.
 361         $this->string_for_js('confirmation', 'admin');
 362         $this->string_for_js('cancel', 'moodle');
 363         $this->string_for_js('yes', 'moodle');
 364
 365         // Alter links in top frame to break out of frames.
 366         if ($page->pagelayout === 'frametop') {
 367             $this->js_init_call('M.util.init_frametop');
 368         }
 369
 370         // Include block drag/drop if editing is on
 371         if ($page->user_is_editing()) {
 372             $params = array(
 373                 'courseid' => $page->course->id,
 374                 'pagetype' => $page->pagetype,
 375                 'pagelayout' => $page->pagelayout,
 376                 'subpage' => $page->subpage,
 377                 'regions' => $page->blocks->get_regions(),
 378                 'contextid' => $page->context->id,
 379             );
 380             if (!empty($page->cm->id)) {
 381                 $params['cmid'] = $page->cm->id;
 382             }
 383             // Strings for drag and drop.
 384             $this->strings_for_js(array('movecontent',
 385                                         'tocontent',
 386                                         'emptydragdropregion'),
 387                                   'moodle');
 388             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 389         }
 390
 391         // Include the YUI CSS Modules.
 392         $page->requires->set_yuicssmodules($page->theme->yuicssmodules);
 393     }
 394
 395     /**
 396      * Determine the correct JS Revision to use for this load.
 397      *
 398      * @return int the jsrev to use.
 399      */
 400     protected function get_jsrev() {
 401         global $CFG;
 402
 403         if (empty($CFG->cachejs)) {
 404             $jsrev = -1;
 405         } else if (empty($CFG->jsrev)) {
 406             $jsrev = 1;
 407         } else {
 408             $jsrev = $CFG->jsrev;
 409         }
 410
 411         return $jsrev;
 412     }
 413
 414     /**
 415      * Ensure that the specified JavaScript file is linked to from this page.
 416      *
 417      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 418      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 419      *
 420      * By default the link is put at the end of the page, since this gives best page-load performance.
 421      *
 422      * Even if a particular script is requested more than once, it will only be linked
 423      * to once.
 424      *
 425      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 426      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 427      * @param bool $inhead initialise in head
 428      */
 429     public function js($url, $inhead = false) {
 430         $url = $this->js_fix_url($url);
 431         $where = $inhead ? 'head' : 'footer';
 432         $this->jsincludes[$where][$url->out()] = $url;
 433     }
 434
 435     /**
 436      * Request inclusion of jQuery library in the page.
 437      *
 438      * NOTE: this should not be used in official Moodle distribution!
 439      *
 440      * {@see http://docs.moodle.org/dev/jQuery}
 441      */
 442     public function jquery() {
 443         $this->jquery_plugin('jquery');
 444     }
 445
 446     /**
 447      * Request inclusion of jQuery plugin.
 448      *
 449      * NOTE: this should not be used in official Moodle distribution!
 450      *
 451      * jQuery plugins are located in plugin/jquery/* subdirectory,
 452      * plugin/jquery/plugins.php lists all available plugins.
 453      *
 454      * Included core plugins:
 455      *   - jQuery UI
 456      *
 457      * Add-ons may include extra jQuery plugins in jquery/ directory,
 458      * plugins.php file defines the mapping between plugin names and
 459      * necessary page includes.
 460      *
 461      * Examples:
 462      * <code>
 463      *   // file: mod/xxx/view.php
 464      *   $PAGE->requires->jquery();
 465      *   $PAGE->requires->jquery_plugin('ui');
 466      *   $PAGE->requires->jquery_plugin('ui-css');
 467      * </code>
 468      *
 469      * <code>
 470      *   // file: theme/yyy/lib.php
 471      *   function theme_yyy_page_init(moodle_page $page) {
 472      *       $page->requires->jquery();
 473      *       $page->requires->jquery_plugin('ui');
 474      *       $page->requires->jquery_plugin('ui-css');
 475      *   }
 476      * </code>
 477      *
 478      * <code>
 479      *   // file: blocks/zzz/block_zzz.php
 480      *   public function get_required_javascript() {
 481      *       parent::get_required_javascript();
 482      *       $this->page->requires->jquery();
 483      *       $page->requires->jquery_plugin('ui');
 484      *       $page->requires->jquery_plugin('ui-css');
 485      *   }
 486      * </code>
 487      *
 488      * {@see http://docs.moodle.org/dev/jQuery}
 489      *
 490      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 491      * @param string $component name of the component
 492      * @return bool success
 493      */
 494     public function jquery_plugin($plugin, $component = 'core') {
 495         global $CFG;
 496
 497         if ($this->headdone) {
 498             debugging('Can not add jQuery plugins after starting page output!');
 499             return false;
 500         }
 501
 502         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css'))) {
 503             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 504             $component = 'core';
 505         } else if ($component !== 'core' and strpos($component, '_') === false) {
 506             // Let's normalise the legacy activity names, Frankenstyle rulez!
 507             $component = 'mod_' . $component;
 508         }
 509
 510         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 511             // Make sure the jQuery itself is always loaded first,
 512             // the order of all other plugins depends on order of $PAGE_>requires->.
 513             $this->jquery_plugin('jquery', 'core');
 514         }
 515
 516         if (isset($this->jqueryplugins[$plugin])) {
 517             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 518             return true;
 519         }
 520
 521         $componentdir = core_component::get_component_directory($component);
 522         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 523             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 524             return false;
 525         }
 526
 527         $plugins = array();
 528         require("$componentdir/jquery/plugins.php");
 529
 530         if (!isset($plugins[$plugin])) {
 531             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 532             return false;
 533         }
 534
 535         $this->jqueryplugins[$plugin] = new stdClass();
 536         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 537         $this->jqueryplugins[$plugin]->component = $component;
 538         $this->jqueryplugins[$plugin]->urls      = array();
 539
 540         foreach ($plugins[$plugin]['files'] as $file) {
 541             if ($CFG->debugdeveloper) {
 542                 if (!file_exists("$componentdir/jquery/$file")) {
 543                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 544                     continue;
 545                 }
 546                 $file = str_replace('.min.css', '.css', $file);
 547                 $file = str_replace('.min.js', '.js', $file);
 548             }
 549             if (!file_exists("$componentdir/jquery/$file")) {
 550                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 551                 continue;
 552             }
 553             if (!empty($CFG->slasharguments)) {
 554                 $url = new moodle_url("/theme/jquery.php");
 555                 $url->set_slashargument("/$component/$file");
 556
 557             } else {
 558                 // This is not really good, we need slasharguments for relative links, this means no caching...
 559                 $path = realpath("$componentdir/jquery/$file");
 560                 if (strpos($path, $CFG->dirroot) === 0) {
 561                     $url = $CFG->wwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 562                     // Replace all occurences of backslashes characters in url to forward slashes.
 563                     $url = str_replace('\\', '/', $url);
 564                     $url = new moodle_url($url);
 565                 } else {
 566                     // Bad luck, fix your server!
 567                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 568                     continue;
 569                 }
 570             }
 571             $this->jqueryplugins[$plugin]->urls[] = $url;
 572         }
 573
 574         return true;
 575     }
 576
 577     /**
 578      * Request replacement of one jQuery plugin by another.
 579      *
 580      * This is useful when themes want to replace the jQuery UI theme,
 581      * the problem is that theme can not prevent others from including the core ui-css plugin.
 582      *
 583      * Example:
 584      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 585      *  2/ write theme/yourtheme/jquery/plugins.php
 586      *  3/ init jQuery from theme
 587      *
 588      * <code>
 589      *   // file theme/yourtheme/lib.php
 590      *   function theme_yourtheme_page_init($page) {
 591      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 592      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 593      *   }
 594      * </code>
 595      *
 596      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 597      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 598      *
 599      * {@see http://docs.moodle.org/dev/jQuery}
 600      *
 601      * @param string $oldplugin original plugin
 602      * @param string $newplugin the replacement
 603      */
 604     public function jquery_override_plugin($oldplugin, $newplugin) {
 605         if ($this->headdone) {
 606             debugging('Can not override jQuery plugins after starting page output!');
 607             return;
 608         }
 609         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 610     }
 611
 612     /**
 613      * Return jQuery related markup for page start.
 614      * @return string
 615      */
 616     protected function get_jquery_headcode() {
 617         if (empty($this->jqueryplugins['jquery'])) {
 618             // If nobody requested jQuery then do not bother to load anything.
 619             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 620             return '';
 621         }
 622
 623         $included = array();
 624         $urls = array();
 625
 626         foreach ($this->jqueryplugins as $name => $unused) {
 627             if (isset($included[$name])) {
 628                 continue;
 629             }
 630             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 631                 // The following loop tries to resolve the replacements,
 632                 // use max 100 iterations to prevent infinite loop resulting
 633                 // in blank page.
 634                 $cyclic = true;
 635                 $oldname = $name;
 636                 for ($i=0; $i<100; $i++) {
 637                     $name = $this->jquerypluginoverrides[$name];
 638                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 639                         $cyclic = false;
 640                         break;
 641                     }
 642                 }
 643                 if ($cyclic) {
 644                     // We can not do much with cyclic references here, let's use the old plugin.
 645                     $name = $oldname;
 646                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 647
 648                 } else if (empty($name)) {
 649                     // Developer requested removal of the plugin.
 650                     continue;
 651
 652                 } else if (!isset($this->jqueryplugins[$name])) {
 653                     debugging("Unknown jQuery override plugin '$name' detected");
 654                     $name = $oldname;
 655
 656                 } else if (isset($included[$name])) {
 657                     // The plugin was already included, easy.
 658                     continue;
 659                 }
 660             }
 661
 662             $plugin = $this->jqueryplugins[$name];
 663             $urls = array_merge($urls, $plugin->urls);
 664             $included[$name] = true;
 665         }
 666
 667         $output = '';
 668         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 669         foreach ($urls as $url) {
 670             if (preg_match('/\.js$/', $url)) {
 671                 $output .= html_writer::script('', $url);
 672             } else if (preg_match('/\.css$/', $url)) {
 673                 $attributes['href'] = $url;
 674                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 675             }
 676         }
 677
 678         return $output;
 679     }
 680
 681     /**
 682      * Returns the actual url through which a script is served.
 683      *
 684      * @param moodle_url|string $url full moodle url, or shortened path to script
 685      * @return moodle_url
 686      */
 687     protected function js_fix_url($url) {
 688         global $CFG;
 689
 690         if ($url instanceof moodle_url) {
 691             return $url;
 692         } else if (strpos($url, '/') === 0) {
 693             // Fix the admin links if needed.
 694             if ($CFG->admin !== 'admin') {
 695                 if (strpos($url, "/admin/") === 0) {
 696                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 697                 }
 698             }
 699             if (debugging()) {
 700                 // Check file existence only when in debug mode.
 701                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 702                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 703                 }
 704             }
 705             if (substr($url, -3) === '.js') {
 706                 $jsrev = $this->get_jsrev();
 707                 if (empty($CFG->slasharguments)) {
 708                     return new moodle_url('/lib/javascript.php', array('rev'=>$jsrev, 'jsfile'=>$url));
 709                 } else {
 710                     $returnurl = new moodle_url('/lib/javascript.php');
 711                     $returnurl->set_slashargument('/'.$jsrev.$url);
 712                     return $returnurl;
 713                 }
 714             } else {
 715                 return new moodle_url($url);
 716             }
 717         } else {
 718             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 719         }
 720     }
 721
 722     /**
 723      * Find out if JS module present and return details.
 724      *
 725      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 726      * @return array description of module or null if not found
 727      */
 728     protected function find_module($component) {
 729         global $CFG, $PAGE;
 730
 731         $module = null;
 732
 733         if (strpos($component, 'core_') === 0) {
 734             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 735             // so that we do nto have to repeat the definition of these modules over and over again.
 736             switch($component) {
 737                 case 'core_filepicker':
 738                     $module = array('name'     => 'core_filepicker',
 739                                     'fullpath' => '/repository/filepicker.js',
 740                                     'requires' => array(
 741                                         'base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form',
 742                                         'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin',
 743                                         'escape', 'moodle-core_filepicker', 'moodle-core-notification-dialogue'
 744                                     ),
 745                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 746                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 747                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 748                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 749                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 750                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 751                                                         array('referencesexist', 'repository'), array('select', 'repository')
 752                                                     ));
 753                     break;
 754                 case 'core_comment':
 755                     $module = array('name'     => 'core_comment',
 756                                     'fullpath' => '/comment/comment.js',
 757                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay', 'escape'),
 758                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 759                                 );
 760                     break;
 761                 case 'core_role':
 762                     $module = array('name'     => 'core_role',
 763                                     'fullpath' => '/admin/roles/module.js',
 764                                     'requires' => array('node', 'cookie'));
 765                     break;
 766                 case 'core_completion':
 767                     $module = array('name'     => 'core_completion',
 768                                     'fullpath' => '/course/completion.js');
 769                     break;
 770                 case 'core_message':
 771                     $module = array('name'     => 'core_message',
 772                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 773                                     'fullpath' => '/message/module.js');
 774                     break;
 775                 case 'core_group':
 776                     $module = array('name'     => 'core_group',
 777                                     'fullpath' => '/group/module.js',
 778                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 779                     break;
 780                 case 'core_question_engine':
 781                     $module = array('name'     => 'core_question_engine',
 782                                     'fullpath' => '/question/qengine.js',
 783                                     'requires' => array('node', 'event'));
 784                     break;
 785                 case 'core_rating':
 786                     $module = array('name'     => 'core_rating',
 787                                     'fullpath' => '/rating/module.js',
 788                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 789                     break;
 790                 case 'core_dndupload':
 791                     $module = array('name'     => 'core_dndupload',
 792                                     'fullpath' => '/lib/form/dndupload.js',
 793                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 794                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 795                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesfile', 'error'),
 796                                                         array('sizegb', 'moodle'), array('sizemb', 'moodle'), array('sizekb', 'moodle'), array('sizeb', 'moodle'),
 797                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 798                                                     ));
 799                     break;
 800             }
 801
 802         } else {
 803             if ($dir = core_component::get_component_directory($component)) {
 804                 if (file_exists("$dir/module.js")) {
 805                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 806                         $dir = substr($dir, strlen($CFG->dirroot));
 807                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 808                     }
 809                 }
 810             }
 811         }
 812
 813         return $module;
 814     }
 815
 816     /**
 817      * Append YUI3 module to default YUI3 JS loader.
 818      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 819      *
 820      * @param string|array $module name of module (details are autodetected), or full module specification as array
 821      * @return void
 822      */
 823     public function js_module($module) {
 824         global $CFG;
 825
 826         if (empty($module)) {
 827             throw new coding_exception('Missing YUI3 module name or full description.');
 828         }
 829
 830         if (is_string($module)) {
 831             $module = $this->find_module($module);
 832         }
 833
 834         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 835             throw new coding_exception('Missing YUI3 module details.');
 836         }
 837
 838         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 839         // Add all needed strings.
 840         if (!empty($module['strings'])) {
 841             foreach ($module['strings'] as $string) {
 842                 $identifier = $string[0];
 843                 $component = isset($string[1]) ? $string[1] : 'moodle';
 844                 $a = isset($string[2]) ? $string[2] : null;
 845                 $this->string_for_js($identifier, $component, $a);
 846             }
 847         }
 848         unset($module['strings']);
 849
 850         // Process module requirements and attempt to load each. This allows
 851         // moodle modules to require each other.
 852         if (!empty($module['requires'])){
 853             foreach ($module['requires'] as $requirement) {
 854                 $rmodule = $this->find_module($requirement);
 855                 if (is_array($rmodule)) {
 856                     $this->js_module($rmodule);
 857                 }
 858             }
 859         }
 860
 861         if ($this->headdone) {
 862             $this->extramodules[$module['name']] = $module;
 863         } else {
 864             $this->YUI_config->add_module_config($module['name'], $module);
 865         }
 866     }
 867
 868     /**
 869      * Returns true if the module has already been loaded.
 870      *
 871      * @param string|array $module
 872      * @return bool True if the module has already been loaded
 873      */
 874     protected function js_module_loaded($module) {
 875         if (is_string($module)) {
 876             $modulename = $module;
 877         } else {
 878             $modulename = $module['name'];
 879         }
 880         return array_key_exists($modulename, $this->YUI_config->modules) ||
 881                array_key_exists($modulename, $this->extramodules);
 882     }
 883
 884     /**
 885      * Ensure that the specified CSS file is linked to from this page.
 886      *
 887      * Because stylesheet links must go in the <head> part of the HTML, you must call
 888      * this function before {@link get_head_code()} is called. That normally means before
 889      * the call to print_header. If you call it when it is too late, an exception
 890      * will be thrown.
 891      *
 892      * Even if a particular style sheet is requested more than once, it will only
 893      * be linked to once.
 894      *
 895      * Please note use of this feature is strongly discouraged,
 896      * it is suitable only for places where CSS is submitted directly by teachers.
 897      * (Students must not be allowed to submit any external CSS because it may
 898      * contain embedded javascript!). Example of correct use is mod/data.
 899      *
 900      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 901      *   For example:
 902      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 903      */
 904     public function css($stylesheet) {
 905         global $CFG;
 906
 907         if ($this->headdone) {
 908             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 909         }
 910
 911         if ($stylesheet instanceof moodle_url) {
 912             // ok
 913         } else if (strpos($stylesheet, '/') === 0) {
 914             $stylesheet = new moodle_url($stylesheet);
 915         } else {
 916             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 917         }
 918
 919         $this->cssurls[$stylesheet->out()] = $stylesheet;
 920     }
 921
 922     /**
 923      * Add theme stylesheet to page - do not use from plugin code,
 924      * this should be called only from the core renderer!
 925      *
 926      * @param moodle_url $stylesheet
 927      * @return void
 928      */
 929     public function css_theme(moodle_url $stylesheet) {
 930         $this->cssthemeurls[] = $stylesheet;
 931     }
 932
 933     /**
 934      * Ensure that a skip link to a given target is printed at the top of the <body>.
 935      *
 936      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 937      * will be thrown). That normally means you must call this before the call to print_header.
 938      *
 939      * If you ask for a particular skip link to be printed, it is then your responsibility
 940      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 941      * page, so that the skip link goes somewhere.
 942      *
 943      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 944      *
 945      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 946      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 947      */
 948     public function skip_link_to($target, $linktext) {
 949         if ($this->topofbodydone) {
 950             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 951             return;
 952         }
 953         $this->skiplinks[$target] = $linktext;
 954     }
 955
 956     /**
 957      * !!!DEPRECATED!!! please use js_init_call() if possible
 958      * Ensure that the specified JavaScript function is called from an inline script
 959      * somewhere on this page.
 960      *
 961      * By default the call will be put in a script tag at the
 962      * end of the page after initialising Y instance, since this gives best page-load
 963      * performance and allows you to use YUI3 library.
 964      *
 965      * If you request that a particular function is called several times, then
 966      * that is what will happen (unlike linking to a CSS or JS file, where only
 967      * one link will be output).
 968      *
 969      * The main benefit of the method is the automatic encoding of all function parameters.
 970      *
 971      * @deprecated
 972      *
 973      * @param string $function the name of the JavaScritp function to call. Can
 974      *      be a compound name like 'Y.Event.purgeElement'. Can also be
 975      *      used to create and object by using a 'function name' like 'new user_selector'.
 976      * @param array $arguments and array of arguments to be passed to the function.
 977      *      When generating the function call, this will be escaped using json_encode,
 978      *      so passing objects and arrays should work.
 979      * @param bool $ondomready If tru the function is only called when the dom is
 980      *      ready for manipulation.
 981      * @param int $delay The delay before the function is called.
 982      */
 983     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
 984         $where = $ondomready ? 'ondomready' : 'normal';
 985         $this->jscalls[$where][] = array($function, $arguments, $delay);
 986     }
 987
 988     /**
 989      * This function appends a block of code to the AMD specific javascript block executed
 990      * in the page footer, just after loading the requirejs library.
 991      *
 992      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
 993      *
 994      * @param string $code The JS code to append.
 995      */
 996     public function js_amd_inline($code) {
 997         $this->amdjscode[] = $code;
 998     }
 999
1000     /**
1001      * This function creates a minimal JS script that requires and calls a single function from an AMD module with arguments.
1002      * If it is called multiple times, it will be executed multiple times.
1003      *
1004      * @param string $fullmodule The format for module names is <component name>/<module name>.
1005      * @param string $func The function from the module to call
1006      * @param array $params The params to pass to the function. They will be json encoded, so no nasty classes/types please.
1007      */
1008     public function js_call_amd($fullmodule, $func, $params = array()) {
1009         global $CFG;
1010
1011         list($component, $module) = explode('/', $fullmodule, 2);
1012
1013         $component = clean_param($component, PARAM_COMPONENT);
1014         $module = clean_param($module, PARAM_ALPHANUMEXT);
1015         $func = clean_param($func, PARAM_ALPHANUMEXT);
1016
1017         $jsonparams = array();
1018         foreach ($params as $param) {
1019             $jsonparams[] = json_encode($param);
1020         }
1021         $strparams = implode(', ', $jsonparams);
1022         if ($CFG->debugdeveloper) {
1023             $toomanyparamslimit = 1024;
1024             if (strlen($strparams) > $toomanyparamslimit) {
1025                 debugging('Too many params passed to js_call_amd("' . $fullmodule . '", "' . $func . '")', DEBUG_DEVELOPER);
1026             }
1027         }
1028
1029         $js = 'require(["' . $component . '/' . $module . '"], function(amd) { amd.' . $func . '(' . $strparams . '); });';
1030
1031         $this->js_amd_inline($js);
1032     }
1033
1034     /**
1035      * Creates a JavaScript function call that requires one or more modules to be loaded.
1036      *
1037      * This function can be used to include all of the standard YUI module types within JavaScript:
1038      *     - YUI3 modules    [node, event, io]
1039      *     - YUI2 modules    [yui2-*]
1040      *     - Moodle modules  [moodle-*]
1041      *     - Gallery modules [gallery-*]
1042      *
1043      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1044      * @see js_call_amd()
1045      *
1046      * @param array|string $modules One or more modules
1047      * @param string $function The function to call once modules have been loaded
1048      * @param array $arguments An array of arguments to pass to the function
1049      * @param string $galleryversion Deprecated: The gallery version to use
1050      * @param bool $ondomready
1051      */
1052     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1053         if (!is_array($modules)) {
1054             $modules = array($modules);
1055         }
1056
1057         if ($galleryversion != null) {
1058             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1059         }
1060
1061         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1062         if ($ondomready) {
1063             $jscode = "Y.on('domready', function() { $jscode });";
1064         }
1065         $this->jsinitcode[] = $jscode;
1066     }
1067
1068     /**
1069      * Set the CSS Modules to be included from YUI.
1070      *
1071      * @param array $modules The list of YUI CSS Modules to include.
1072      */
1073     public function set_yuicssmodules(array $modules = array()) {
1074         $this->yuicssmodules = $modules;
1075     }
1076
1077     /**
1078      * Ensure that the specified JavaScript function is called from an inline script
1079      * from page footer.
1080      *
1081      * @param string $function the name of the JavaScritp function to with init code,
1082      *      usually something like 'M.mod_mymodule.init'
1083      * @param array $extraarguments and array of arguments to be passed to the function.
1084      *      The first argument is always the YUI3 Y instance with all required dependencies
1085      *      already loaded.
1086      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1087      * @param array $module JS module specification array
1088      */
1089     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1090         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1091         if (!$module) {
1092             // Detect module automatically.
1093             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1094                 $module = $this->find_module($matches[1]);
1095             }
1096         }
1097
1098         $this->js_init_code($jscode, $ondomready, $module);
1099     }
1100
1101     /**
1102      * Add short static javascript code fragment to page footer.
1103      * This is intended primarily for loading of js modules and initialising page layout.
1104      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1105      * may override it.
1106      *
1107      * @param string $jscode
1108      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1109      * @param array $module JS module specification array
1110      */
1111     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1112         $jscode = trim($jscode, " ;\n"). ';';
1113
1114         $uniqid = html_writer::random_id();
1115         $startjs = " M.util.js_pending('" . $uniqid . "');";
1116         $endjs = " M.util.js_complete('" . $uniqid . "');";
1117
1118         if ($module) {
1119             $this->js_module($module);
1120             $modulename = $module['name'];
1121             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1122         }
1123
1124         if ($ondomready) {
1125             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1126         }
1127
1128         $this->jsinitcode[] = $jscode;
1129     }
1130
1131     /**
1132      * Make a language string available to JavaScript.
1133      *
1134      * All the strings will be available in a M.str object in the global namespace.
1135      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1136      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1137      * equivalent in the current language.
1138      *
1139      * The arguments to this function are just like the arguments to get_string
1140      * except that $component is not optional, and there are some aspects to consider
1141      * when the string contains {$a} placeholder.
1142      *
1143      * If the string does not contain any {$a} placeholder, you can simply use
1144      * M.str.component.identifier to obtain it. If you prefer, you can call
1145      * M.util.get_string(identifier, component) to get the same result.
1146      *
1147      * If you need to use {$a} placeholders, there are two options. Either the
1148      * placeholder should be substituted in PHP on server side or it should
1149      * be substituted in Javascript at client side.
1150      *
1151      * To substitute the placeholder at server side, just provide the required
1152      * value for the placeholder when you require the string. Because each string
1153      * is only stored once in the JavaScript (based on $identifier and $module)
1154      * you cannot get the same string with two different values of $a. If you try,
1155      * an exception will be thrown. Once the placeholder is substituted, you can
1156      * use M.str or M.util.get_string() as shown above:
1157      *
1158      *     // Require the string in PHP and replace the placeholder.
1159      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1160      *     // Use the result of the substitution in Javascript.
1161      *     alert(M.str.moodle.fullnamedisplay);
1162      *
1163      * To substitute the placeholder at client side, use M.util.get_string()
1164      * function. It implements the same logic as {@link get_string()}:
1165      *
1166      *     // Require the string in PHP but keep {$a} as it is.
1167      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1168      *     // Provide the values on the fly in Javascript.
1169      *     user = { firstname : 'Harry', lastname : 'Potter' }
1170      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1171      *
1172      * If you do need the same string expanded with different $a values in PHP
1173      * on server side, then the solution is to put them in your own data structure
1174      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1175      *
1176      * @param string $identifier the desired string.
1177      * @param string $component the language file to look in.
1178      * @param mixed $a any extra data to add into the string (optional).
1179      */
1180     public function string_for_js($identifier, $component, $a = null) {
1181         if (!$component) {
1182             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1183         }
1184         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1185             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1186                     "from lang file '$component' with different \$a parameter?");
1187         }
1188         if (!isset($this->stringsforjs[$component][$identifier])) {
1189             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1190             $this->stringsforjs_as[$component][$identifier] = $a;
1191         }
1192     }
1193
1194     /**
1195      * Make an array of language strings available for JS.
1196      *
1197      * This function calls the above function {@link string_for_js()} for each requested
1198      * string in the $identifiers array that is passed to the argument for a single module
1199      * passed in $module.
1200      *
1201      * <code>
1202      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1203      *
1204      * // The above is identical to calling:
1205      *
1206      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1207      * $PAGE->requires->string_for_js('two', 'mymod');
1208      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1209      * </code>
1210      *
1211      * @param array $identifiers An array of desired strings
1212      * @param string $component The module to load for
1213      * @param mixed $a This can either be a single variable that gets passed as extra
1214      *         information for every string or it can be an array of mixed data where the
1215      *         key for the data matches that of the identifier it is meant for.
1216      *
1217      */
1218     public function strings_for_js($identifiers, $component, $a = null) {
1219         foreach ($identifiers as $key => $identifier) {
1220             if (is_array($a) && array_key_exists($key, $a)) {
1221                 $extra = $a[$key];
1222             } else {
1223                 $extra = $a;
1224             }
1225             $this->string_for_js($identifier, $component, $extra);
1226         }
1227     }
1228
1229     /**
1230      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1231      *
1232      * Make some data from PHP available to JavaScript code.
1233      *
1234      * For example, if you call
1235      * <pre>
1236      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1237      * </pre>
1238      * then in JavsScript mydata.name will be 'Moodle'.
1239      *
1240      * @deprecated
1241      * @param string $variable the the name of the JavaScript variable to assign the data to.
1242      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1243      *      should be considered an experimental feature.
1244      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1245      *      so passing objects and arrays should work.
1246      * @param bool $inhead initialise in head
1247      * @return void
1248      */
1249     public function data_for_js($variable, $data, $inhead=false) {
1250         $where = $inhead ? 'head' : 'footer';
1251         $this->jsinitvariables[$where][] = array($variable, $data);
1252     }
1253
1254     /**
1255      * Creates a YUI event handler.
1256      *
1257      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1258      * @param string $event A valid DOM event (click, mousedown, change etc.)
1259      * @param string $function The name of the function to call
1260      * @param array  $arguments An optional array of argument parameters to pass to the function
1261      */
1262     public function event_handler($selector, $event, $function, array $arguments = null) {
1263         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1264     }
1265
1266     /**
1267      * Returns code needed for registering of event handlers.
1268      * @return string JS code
1269      */
1270     protected function get_event_handler_code() {
1271         $output = '';
1272         foreach ($this->eventhandlers as $h) {
1273             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1274         }
1275         return $output;
1276     }
1277
1278     /**
1279      * Get the inline JavaScript code that need to appear in a particular place.
1280      * @param bool $ondomready
1281      * @return string
1282      */
1283     protected function get_javascript_code($ondomready) {
1284         $where = $ondomready ? 'ondomready' : 'normal';
1285         $output = '';
1286         if ($this->jscalls[$where]) {
1287             foreach ($this->jscalls[$where] as $data) {
1288                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1289             }
1290             if (!empty($ondomready)) {
1291                 $output = "    Y.on('domready', function() {\n$output\n});";
1292             }
1293         }
1294         return $output;
1295     }
1296
1297     /**
1298      * Returns js code to be executed when Y is available.
1299      * @return string
1300      */
1301     protected function get_javascript_init_code() {
1302         if (count($this->jsinitcode)) {
1303             return implode("\n", $this->jsinitcode) . "\n";
1304         }
1305         return '';
1306     }
1307
1308     /**
1309      * Returns js code to load amd module loader, then insert inline script tags
1310      * that contain require() calls using RequireJS.
1311      * @return string
1312      */
1313     protected function get_amd_footercode() {
1314         global $CFG;
1315         $output = '';
1316         $jsrev = $this->get_jsrev();
1317
1318         $jsloader = new moodle_url('/lib/javascript.php');
1319         $jsloader->set_slashargument('/' . $jsrev . '/');
1320         $requirejsloader = new moodle_url('/lib/requirejs.php');
1321         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1322
1323         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1324
1325         // No extension required unless slash args is disabled.
1326         $jsextension = '.js';
1327         if (!empty($CFG->slasharguments)) {
1328             $jsextension = '';
1329         }
1330
1331         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1332         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1333         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1334
1335         $output .= html_writer::script($requirejsconfig);
1336         if ($CFG->debugdeveloper) {
1337             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1338         } else {
1339             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1340         }
1341
1342         // First include must be to a module with no dependencies, this prevents multiple requests.
1343         $prefix = "require(['core/first'], function() {\n";
1344         $suffix = "\n});";
1345         $output .= html_writer::script($prefix . implode(";\n", $this->amdjscode) . $suffix);
1346         return $output;
1347     }
1348
1349     /**
1350      * Returns basic YUI3 CSS code.
1351      *
1352      * @return string
1353      */
1354     protected function get_yui3lib_headcss() {
1355         global $CFG;
1356
1357         $yuiformat = '-min';
1358         if ($this->yui3loader->filter === 'RAW') {
1359             $yuiformat = '';
1360         }
1361
1362         $code = '';
1363         if ($this->yui3loader->combine) {
1364             if (!empty($this->yuicssmodules)) {
1365                 $modules = array();
1366                 foreach ($this->yuicssmodules as $module) {
1367                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1368                 }
1369                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1370             }
1371             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1372
1373         } else {
1374             if (!empty($this->yuicssmodules)) {
1375                 foreach ($this->yuicssmodules as $module) {
1376                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1377                 }
1378             }
1379             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1380         }
1381
1382         if ($this->yui3loader->filter === 'RAW') {
1383             $code = str_replace('-min.css', '.css', $code);
1384         } else if ($this->yui3loader->filter === 'DEBUG') {
1385             $code = str_replace('-min.css', '.css', $code);
1386         }
1387         return $code;
1388     }
1389
1390     /**
1391      * Returns basic YUI3 JS loading code.
1392      *
1393      * @return string
1394      */
1395     protected function get_yui3lib_headcode() {
1396         global $CFG;
1397
1398         $jsrev = $this->get_jsrev();
1399
1400         $yuiformat = '-min';
1401         if ($this->yui3loader->filter === 'RAW') {
1402             $yuiformat = '';
1403         }
1404
1405         $format = '-min';
1406         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1407             $format = '-debug';
1408         }
1409
1410         $rollupversion = $CFG->yui3version;
1411         if (!empty($CFG->yuipatchlevel)) {
1412             $rollupversion .= '_' . $CFG->yuipatchlevel;
1413         }
1414
1415         $baserollups = array(
1416             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1417         );
1418
1419         if ($this->yui3loader->combine) {
1420             return '<script type="text/javascript" src="' .
1421                     $this->yui3loader->local_comboBase .
1422                     implode('&amp;', $baserollups) .
1423                     '"></script>';
1424         } else {
1425             $code = '';
1426             foreach ($baserollups as $rollup) {
1427                 $code .= '<script type="text/javascript" src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1428             }
1429             return $code;
1430         }
1431
1432     }
1433
1434     /**
1435      * Returns html tags needed for inclusion of theme CSS.
1436      *
1437      * @return string
1438      */
1439     protected function get_css_code() {
1440         // First of all the theme CSS, then any custom CSS
1441         // Please note custom CSS is strongly discouraged,
1442         // because it can not be overridden by themes!
1443         // It is suitable only for things like mod/data which accepts CSS from teachers.
1444         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1445
1446         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1447         $code = $this->get_yui3lib_headcss();
1448
1449         // This line of code may look funny but it is currently required in order
1450         // to avoid MASSIVE display issues in Internet Explorer.
1451         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1452         // ignored whenever another resource is added until such time as a redraw
1453         // is forced, usually by moving the mouse over the affected element.
1454         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1455
1456         $urls = $this->cssthemeurls + $this->cssurls;
1457         foreach ($urls as $url) {
1458             $attributes['href'] = $url;
1459             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1460             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1461             unset($attributes['id']);
1462         }
1463
1464         return $code;
1465     }
1466
1467     /**
1468      * Adds extra modules specified after printing of page header.
1469      *
1470      * @return string
1471      */
1472     protected function get_extra_modules_code() {
1473         if (empty($this->extramodules)) {
1474             return '';
1475         }
1476         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1477     }
1478
1479     /**
1480      * Generate any HTML that needs to go inside the <head> tag.
1481      *
1482      * Normally, this method is called automatically by the code that prints the
1483      * <head> tag. You should not normally need to call it in your own code.
1484      *
1485      * @param moodle_page $page
1486      * @param core_renderer $renderer
1487      * @return string the HTML code to to inside the <head> tag.
1488      */
1489     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1490         global $CFG;
1491
1492         // Note: the $page and $output are not stored here because it would
1493         // create circular references in memory which prevents garbage collection.
1494         $this->init_requirements_data($page, $renderer);
1495
1496         $output = '';
1497
1498         // Add all standard CSS for this page.
1499         $output .= $this->get_css_code();
1500
1501         // Set up the M namespace.
1502         $js = "var M = {}; M.yui = {};\n";
1503
1504         // Capture the time now ASAP during page load. This minimises the lag when
1505         // we try to relate times on the server to times in the browser.
1506         // An example of where this is used is the quiz countdown timer.
1507         $js .= "M.pageloadstarttime = new Date();\n";
1508
1509         // Add a subset of Moodle configuration to the M namespace.
1510         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1511
1512         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1513         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1514         //       this needs to be done before including any other script.
1515         $js .= $this->YUI_config->get_config_functions();
1516         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1517         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1518         $js = $this->YUI_config->update_header_js($js);
1519
1520         $output .= html_writer::script($js);
1521
1522         // Add variables.
1523         if ($this->jsinitvariables['head']) {
1524             $js = '';
1525             foreach ($this->jsinitvariables['head'] as $data) {
1526                 list($var, $value) = $data;
1527                 $js .= js_writer::set_variable($var, $value, true);
1528             }
1529             $output .= html_writer::script($js);
1530         }
1531
1532         // Mark head sending done, it is not possible to anything there.
1533         $this->headdone = true;
1534
1535         return $output;
1536     }
1537
1538     /**
1539      * Generate any HTML that needs to go at the start of the <body> tag.
1540      *
1541      * Normally, this method is called automatically by the code that prints the
1542      * <head> tag. You should not normally need to call it in your own code.
1543      *
1544      * @param renderer_base $renderer
1545      * @return string the HTML code to go at the start of the <body> tag.
1546      */
1547     public function get_top_of_body_code(renderer_base $renderer) {
1548         // First the skip links.
1549         $output = $renderer->render_skip_links($this->skiplinks);
1550
1551         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1552         $output .= $this->get_yui3lib_headcode();
1553
1554         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1555         $output .= $this->get_jquery_headcode();
1556
1557         // Link our main JS file, all core stuff should be there.
1558         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1559
1560         // All the other linked things from HEAD - there should be as few as possible.
1561         if ($this->jsincludes['head']) {
1562             foreach ($this->jsincludes['head'] as $url) {
1563                 $output .= html_writer::script('', $url);
1564             }
1565         }
1566
1567         // Then the clever trick for hiding of things not needed when JS works.
1568         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1569         $this->topofbodydone = true;
1570         return $output;
1571     }
1572
1573     /**
1574      * Generate any HTML that needs to go at the end of the page.
1575      *
1576      * Normally, this method is called automatically by the code that prints the
1577      * page footer. You should not normally need to call it in your own code.
1578      *
1579      * @return string the HTML code to to at the end of the page.
1580      */
1581     public function get_end_code() {
1582         global $CFG;
1583         $output = '';
1584
1585         // Set the log level for the JS logging.
1586         $logconfig = new stdClass();
1587         $logconfig->level = 'warn';
1588         if ($CFG->debugdeveloper) {
1589             $logconfig->level = 'trace';
1590         }
1591         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1592
1593         // Call amd init functions.
1594         $output .= $this->get_amd_footercode();
1595
1596         // Add other requested modules.
1597         $output .= $this->get_extra_modules_code();
1598
1599         $this->js_init_code('M.util.js_complete("init");', true);
1600
1601         // All the other linked scripts - there should be as few as possible.
1602         if ($this->jsincludes['footer']) {
1603             foreach ($this->jsincludes['footer'] as $url) {
1604                 $output .= html_writer::script('', $url);
1605             }
1606         }
1607
1608         // Add all needed strings.
1609         // First add core strings required for some dialogues.
1610         $this->strings_for_js(array(
1611             'confirm',
1612             'yes',
1613             'no',
1614             'areyousure',
1615             'closebuttontitle',
1616             'unknownerror',
1617         ), 'moodle');
1618         if (!empty($this->stringsforjs)) {
1619             $strings = array();
1620             foreach ($this->stringsforjs as $component=>$v) {
1621                 foreach($v as $indentifier => $langstring) {
1622                     $strings[$component][$indentifier] = $langstring->out();
1623                 }
1624             }
1625             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1626         }
1627
1628         // Add variables.
1629         if ($this->jsinitvariables['footer']) {
1630             $js = '';
1631             foreach ($this->jsinitvariables['footer'] as $data) {
1632                 list($var, $value) = $data;
1633                 $js .= js_writer::set_variable($var, $value, true);
1634             }
1635             $output .= html_writer::script($js);
1636         }
1637
1638         $inyuijs = $this->get_javascript_code(false);
1639         $ondomreadyjs = $this->get_javascript_code(true);
1640         $jsinit = $this->get_javascript_init_code();
1641         $handlersjs = $this->get_event_handler_code();
1642
1643         // There is a global Y, make sure it is available in your scope.
1644         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1645
1646         $output .= html_writer::script($js);
1647
1648         return $output;
1649     }
1650
1651     /**
1652      * Have we already output the code in the <head> tag?
1653      *
1654      * @return bool
1655      */
1656     public function is_head_done() {
1657         return $this->headdone;
1658     }
1659
1660     /**
1661      * Have we already output the code at the start of the <body> tag?
1662      *
1663      * @return bool
1664      */
1665     public function is_top_of_body_done() {
1666         return $this->topofbodydone;
1667     }
1668
1669     /**
1670      * Should we generate a bit of content HTML that is only required once  on
1671      * this page (e.g. the contents of the modchooser), now? Basically, we call
1672      * {@link has_one_time_item_been_created()}, and if the thing has not already
1673      * been output, we return true to tell the caller to generate it, and also
1674      * call {@link set_one_time_item_created()} to record the fact that it is
1675      * about to be generated.
1676      *
1677      * That is, a typical usage pattern (in a renderer method) is:
1678      * <pre>
1679      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1680      *     return '';
1681      * }
1682      * // Else generate it.
1683      * </pre>
1684      *
1685      * @param string $thing identifier for the bit of content. Should be of the form
1686      *      frankenstyle_things, e.g. core_course_modchooser.
1687      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1688      */
1689     public function should_create_one_time_item_now($thing) {
1690         if ($this->has_one_time_item_been_created($thing)) {
1691             return false;
1692         }
1693
1694         $this->set_one_time_item_created($thing);
1695         return true;
1696     }
1697
1698     /**
1699      * Has a particular bit of HTML that is only required once  on this page
1700      * (e.g. the contents of the modchooser) already been generated?
1701      *
1702      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1703      * method rather than calling this method directly.
1704      *
1705      * @param string $thing identifier for the bit of content. Should be of the form
1706      *      frankenstyle_things, e.g. core_course_modchooser.
1707      * @return bool whether that bit of output has been created.
1708      */
1709     public function has_one_time_item_been_created($thing) {
1710         return isset($this->onetimeitemsoutput[$thing]);
1711     }
1712
1713     /**
1714      * Indicate that a particular bit of HTML that is only required once on this
1715      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1716      *
1717      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1718      * method rather than calling this method directly.
1719      *
1720      * @param string $thing identifier for the bit of content. Should be of the form
1721      *      frankenstyle_things, e.g. core_course_modchooser.
1722      */
1723     public function set_one_time_item_created($thing) {
1724         if ($this->has_one_time_item_been_created($thing)) {
1725             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1726                     'once per page, but it seems to be being output again.');
1727         }
1728         return $this->onetimeitemsoutput[$thing] = true;
1729     }
1730 }
1731
1732 /**
1733  * This class represents the YUI configuration.
1734  *
1735  * @copyright 2013 Andrew Nicols
1736  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1737  * @since Moodle 2.5
1738  * @package core
1739  * @category output
1740  */
1741 class YUI_config {
1742     /**
1743      * These settings must be public so that when the object is converted to json they are exposed.
1744      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1745      *
1746      * The settings are described and documented in the YUI API at:
1747      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1748      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1749      */
1750     public $debug = false;
1751     public $base;
1752     public $comboBase;
1753     public $combine;
1754     public $filter = null;
1755     public $insertBefore = 'firstthemesheet';
1756     public $groups = array();
1757     public $modules = array();
1758
1759     /**
1760      * @var array List of functions used by the YUI Loader group pattern recognition.
1761      */
1762     protected $jsconfigfunctions = array();
1763
1764     /**
1765      * Create a new group within the YUI_config system.
1766      *
1767      * @param String $name The name of the group. This must be unique and
1768      * not previously used.
1769      * @param Array $config The configuration for this group.
1770      * @return void
1771      */
1772     public function add_group($name, $config) {
1773         if (isset($this->groups[$name])) {
1774             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1775         }
1776         $this->groups[$name] = $config;
1777     }
1778
1779     /**
1780      * Update an existing group configuration
1781      *
1782      * Note, any existing configuration for that group will be wiped out.
1783      * This includes module configuration.
1784      *
1785      * @param String $name The name of the group. This must be unique and
1786      * not previously used.
1787      * @param Array $config The configuration for this group.
1788      * @return void
1789      */
1790     public function update_group($name, $config) {
1791         if (!isset($this->groups[$name])) {
1792             throw new coding_exception('The Moodle YUI module does not exist. You must define the moodle module config using YUI_config->add_module_config first.');
1793         }
1794         $this->groups[$name] = $config;
1795     }
1796
1797     /**
1798      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1799      *
1800      * Only the body of the function should be passed, and not the whole function wrapper.
1801      *
1802      * The JS function your write will be passed a single argument 'name' containing the
1803      * name of the module being loaded.
1804      *
1805      * @param $function String the body of the JavaScript function. This should be used i
1806      * @return String the name of the function to use in the group pattern configuration.
1807      */
1808     public function set_config_function($function) {
1809         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1810         if (isset($this->jsconfigfunctions[$configname])) {
1811             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1812         }
1813         $this->jsconfigfunctions[$configname] = $function;
1814         return '@' . $configname . '@';
1815     }
1816
1817     /**
1818      * Allow setting of the config function described in {@see set_config_function} from a file.
1819      * The contents of this file are then passed to set_config_function.
1820      *
1821      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1822      *
1823      * @param $file The path to the JavaScript function used for YUI configuration.
1824      * @return String the name of the function to use in the group pattern configuration.
1825      */
1826     public function set_config_source($file) {
1827         global $CFG;
1828         $cache = cache::make('core', 'yuimodules');
1829
1830         // Attempt to get the metadata from the cache.
1831         $keyname = 'configfn_' . $file;
1832         $fullpath = $CFG->dirroot . '/' . $file;
1833         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1834             $cache->delete($keyname);
1835             $configfn = file_get_contents($fullpath);
1836         } else {
1837             $configfn = $cache->get($keyname);
1838             if ($configfn === false) {
1839                 require_once($CFG->libdir . '/jslib.php');
1840                 $configfn = core_minify::js_files(array($fullpath));
1841                 $cache->set($keyname, $configfn);
1842             }
1843         }
1844         return $this->set_config_function($configfn);
1845     }
1846
1847     /**
1848      * Retrieve the list of JavaScript functions for YUI_config groups.
1849      *
1850      * @return String The complete set of config functions
1851      */
1852     public function get_config_functions() {
1853         $configfunctions = '';
1854         foreach ($this->jsconfigfunctions as $functionname => $function) {
1855             $configfunctions .= "var {$functionname} = function(me) {";
1856             $configfunctions .= $function;
1857             $configfunctions .= "};\n";
1858         }
1859         return $configfunctions;
1860     }
1861
1862     /**
1863      * Update the header JavaScript with any required modification for the YUI Loader.
1864      *
1865      * @param $js String The JavaScript to manipulate.
1866      * @return String the modified JS string.
1867      */
1868     public function update_header_js($js) {
1869         // Update the names of the the configFn variables.
1870         // The PHP json_encode function cannot handle literal names so we have to wrap
1871         // them in @ and then replace them with literals of the same function name.
1872         foreach ($this->jsconfigfunctions as $functionname => $function) {
1873             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1874         }
1875         return $js;
1876     }
1877
1878     /**
1879      * Add configuration for a specific module.
1880      *
1881      * @param String $name The name of the module to add configuration for.
1882      * @param Array $config The configuration for the specified module.
1883      * @param String $group The name of the group to add configuration for.
1884      * If not specified, then this module is added to the global
1885      * configuration.
1886      * @return void
1887      */
1888     public function add_module_config($name, $config, $group = null) {
1889         if ($group) {
1890             if (!isset($this->groups[$name])) {
1891                 throw new coding_exception('The Moodle YUI module does not exist. You must define the moodle module config using YUI_config->add_module_config first.');
1892             }
1893             if (!isset($this->groups[$group]['modules'])) {
1894                 $this->groups[$group]['modules'] = array();
1895             }
1896             $modules = &$this->groups[$group]['modules'];
1897         } else {
1898             $modules = &$this->modules;
1899         }
1900         $modules[$name] = $config;
1901     }
1902
1903     /**
1904      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
1905      *
1906      * If js caching is disabled, metadata will not be served causing YUI to calculate
1907      * module dependencies as each module is loaded.
1908      *
1909      * If metadata does not exist it will be created and stored in a MUC entry.
1910      *
1911      * @return void
1912      */
1913     public function add_moodle_metadata() {
1914         global $CFG;
1915         if (!isset($this->groups['moodle'])) {
1916             throw new coding_exception('The Moodle YUI module does not exist. You must define the moodle module config using YUI_config->add_module_config first.');
1917         }
1918
1919         if (!isset($this->groups['moodle']['modules'])) {
1920             $this->groups['moodle']['modules'] = array();
1921         }
1922
1923         $cache = cache::make('core', 'yuimodules');
1924         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1925             $metadata = array();
1926             $metadata = $this->get_moodle_metadata();
1927             $cache->delete('metadata');
1928         } else {
1929             // Attempt to get the metadata from the cache.
1930             if (!$metadata = $cache->get('metadata')) {
1931                 $metadata = $this->get_moodle_metadata();
1932                 $cache->set('metadata', $metadata);
1933             }
1934         }
1935
1936         // Merge with any metadata added specific to this page which was added manually.
1937         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
1938                 $metadata);
1939     }
1940
1941     /**
1942      * Determine the module metadata for all moodle YUI modules.
1943      *
1944      * This works through all modules capable of serving YUI modules, and attempts to get
1945      * metadata for each of those modules.
1946      *
1947      * @return Array of module metadata
1948      */
1949     private function get_moodle_metadata() {
1950         $moodlemodules = array();
1951         // Core isn't a plugin type or subsystem - handle it seperately.
1952         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
1953             $moodlemodules = array_merge($moodlemodules, $module);
1954         }
1955
1956         // Handle other core subsystems.
1957         $subsystems = core_component::get_core_subsystems();
1958         foreach ($subsystems as $subsystem => $path) {
1959             if (is_null($path)) {
1960                 continue;
1961             }
1962             if ($module = $this->get_moodle_path_metadata($path)) {
1963                 $moodlemodules = array_merge($moodlemodules, $module);
1964             }
1965         }
1966
1967         // And finally the plugins.
1968         $plugintypes = core_component::get_plugin_types();
1969         foreach ($plugintypes as $plugintype => $pathroot) {
1970             $pluginlist = core_component::get_plugin_list($plugintype);
1971             foreach ($pluginlist as $plugin => $path) {
1972                 if ($module = $this->get_moodle_path_metadata($path)) {
1973                     $moodlemodules = array_merge($moodlemodules, $module);
1974                 }
1975             }
1976         }
1977
1978         return $moodlemodules;
1979     }
1980
1981     /**
1982      * Helper function process and return the YUI metadata for all of the modules under the specified path.
1983      *
1984      * @param String $path the UNC path to the YUI src directory.
1985      * @return Array the complete array for frankenstyle directory.
1986      */
1987     private function get_moodle_path_metadata($path) {
1988         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
1989         $baseyui = $path . '/yui/src';
1990         $modules = array();
1991         if (is_dir($baseyui)) {
1992             $items = new DirectoryIterator($baseyui);
1993             foreach ($items as $item) {
1994                 if ($item->isDot() or !$item->isDir()) {
1995                     continue;
1996                 }
1997                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
1998                 if (!is_readable($metafile)) {
1999                     continue;
2000                 }
2001                 $metadata = file_get_contents($metafile);
2002                 $modules = array_merge($modules, (array) json_decode($metadata));
2003             }
2004         }
2005         return $modules;
2006     }
2007
2008     /**
2009      * Define YUI modules which we have been required to patch between releases.
2010      *
2011      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2012      * external CDN which will serve the true authoritative copy of the code without our patches.
2013      *
2014      * @param String combobase The local combobase
2015      * @param String yuiversion The current YUI version
2016      * @param Int patchlevel The patch level we're working to for YUI
2017      * @param Array patchedmodules An array containing the names of the patched modules
2018      * @return void
2019      */
2020     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2021         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2022         $subversion = $yuiversion . '_' . $patchlevel;
2023
2024         if ($this->comboBase == $combobase) {
2025             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2026             // loader. We just need to specify a different root which includes a slightly different YUI version number
2027             // to include our patchlevel.
2028             $patterns = array();
2029             $modules = array();
2030             foreach ($patchedmodules as $modulename) {
2031                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2032                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2033                 // loaded when the module is loaded anyway.
2034                 $patterns[$modulename] = array(
2035                     'group' => 'yui-patched',
2036                 );
2037                 $modules[$modulename] = array();
2038             }
2039
2040             // Actually add the patch group here.
2041             $this->add_group('yui-patched', array(
2042                 'combine' => true,
2043                 'root' => $subversion . '/',
2044                 'patterns' => $patterns,
2045                 'modules' => $modules,
2046             ));
2047
2048         } else {
2049             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2050             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2051             // local base in browser caches.
2052             $fullpathbase = $combobase . $subversion . '/';
2053             foreach ($patchedmodules as $modulename) {
2054                 $this->modules[$modulename] = array(
2055                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2056                 );
2057             }
2058         }
2059     }
2060 }
2061
2062 /**
2063  * Invalidate all server and client side JS caches.
2064  */
2065 function js_reset_all_caches() {
2066     global $CFG;
2067
2068     $next = time();
2069     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2070         // This resolves problems when reset is requested repeatedly within 1s,
2071         // the < 1h condition prevents accidental switching to future dates
2072         // because we might not recover from it.
2073         $next = $CFG->jsrev+1;
2074     }
2075
2076     set_config('jsrev', $next);
2077 }