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                     $module = array('name'     => 'core_dndupload',
 792                                     'fullpath' => '/lib/form/dndupload.js',
 793                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 794                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 795                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesfile', 'error'),
 796                                                         array('sizegb', 'moodle'), array('sizemb', 'moodle'), array('sizekb', 'moodle'), array('sizeb', 'moodle'),
 797                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 798                                                         array('changesmadereallygoaway', 'moodle')
 799                                                     ));
 800                     break;
 801             }
 802
 803         } else {
 804             if ($dir = core_component::get_component_directory($component)) {
 805                 if (file_exists("$dir/module.js")) {
 806                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 807                         $dir = substr($dir, strlen($CFG->dirroot));
 808                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 809                     }
 810                 }
 811             }
 812         }
 813
 814         return $module;
 815     }
 816
 817     /**
 818      * Append YUI3 module to default YUI3 JS loader.
 819      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 820      *
 821      * @param string|array $module name of module (details are autodetected), or full module specification as array
 822      * @return void
 823      */
 824     public function js_module($module) {
 825         global $CFG;
 826
 827         if (empty($module)) {
 828             throw new coding_exception('Missing YUI3 module name or full description.');
 829         }
 830
 831         if (is_string($module)) {
 832             $module = $this->find_module($module);
 833         }
 834
 835         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 836             throw new coding_exception('Missing YUI3 module details.');
 837         }
 838
 839         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 840         // Add all needed strings.
 841         if (!empty($module['strings'])) {
 842             foreach ($module['strings'] as $string) {
 843                 $identifier = $string[0];
 844                 $component = isset($string[1]) ? $string[1] : 'moodle';
 845                 $a = isset($string[2]) ? $string[2] : null;
 846                 $this->string_for_js($identifier, $component, $a);
 847             }
 848         }
 849         unset($module['strings']);
 850
 851         // Process module requirements and attempt to load each. This allows
 852         // moodle modules to require each other.
 853         if (!empty($module['requires'])){
 854             foreach ($module['requires'] as $requirement) {
 855                 $rmodule = $this->find_module($requirement);
 856                 if (is_array($rmodule)) {
 857                     $this->js_module($rmodule);
 858                 }
 859             }
 860         }
 861
 862         if ($this->headdone) {
 863             $this->extramodules[$module['name']] = $module;
 864         } else {
 865             $this->YUI_config->add_module_config($module['name'], $module);
 866         }
 867     }
 868
 869     /**
 870      * Returns true if the module has already been loaded.
 871      *
 872      * @param string|array $module
 873      * @return bool True if the module has already been loaded
 874      */
 875     protected function js_module_loaded($module) {
 876         if (is_string($module)) {
 877             $modulename = $module;
 878         } else {
 879             $modulename = $module['name'];
 880         }
 881         return array_key_exists($modulename, $this->YUI_config->modules) ||
 882                array_key_exists($modulename, $this->extramodules);
 883     }
 884
 885     /**
 886      * Ensure that the specified CSS file is linked to from this page.
 887      *
 888      * Because stylesheet links must go in the <head> part of the HTML, you must call
 889      * this function before {@link get_head_code()} is called. That normally means before
 890      * the call to print_header. If you call it when it is too late, an exception
 891      * will be thrown.
 892      *
 893      * Even if a particular style sheet is requested more than once, it will only
 894      * be linked to once.
 895      *
 896      * Please note use of this feature is strongly discouraged,
 897      * it is suitable only for places where CSS is submitted directly by teachers.
 898      * (Students must not be allowed to submit any external CSS because it may
 899      * contain embedded javascript!). Example of correct use is mod/data.
 900      *
 901      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 902      *   For example:
 903      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 904      */
 905     public function css($stylesheet) {
 906         global $CFG;
 907
 908         if ($this->headdone) {
 909             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 910         }
 911
 912         if ($stylesheet instanceof moodle_url) {
 913             // ok
 914         } else if (strpos($stylesheet, '/') === 0) {
 915             $stylesheet = new moodle_url($stylesheet);
 916         } else {
 917             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 918         }
 919
 920         $this->cssurls[$stylesheet->out()] = $stylesheet;
 921     }
 922
 923     /**
 924      * Add theme stylesheet to page - do not use from plugin code,
 925      * this should be called only from the core renderer!
 926      *
 927      * @param moodle_url $stylesheet
 928      * @return void
 929      */
 930     public function css_theme(moodle_url $stylesheet) {
 931         $this->cssthemeurls[] = $stylesheet;
 932     }
 933
 934     /**
 935      * Ensure that a skip link to a given target is printed at the top of the <body>.
 936      *
 937      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 938      * will be thrown). That normally means you must call this before the call to print_header.
 939      *
 940      * If you ask for a particular skip link to be printed, it is then your responsibility
 941      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 942      * page, so that the skip link goes somewhere.
 943      *
 944      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 945      *
 946      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 947      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 948      */
 949     public function skip_link_to($target, $linktext) {
 950         if ($this->topofbodydone) {
 951             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 952             return;
 953         }
 954         $this->skiplinks[$target] = $linktext;
 955     }
 956
 957     /**
 958      * !!!DEPRECATED!!! please use js_init_call() if possible
 959      * Ensure that the specified JavaScript function is called from an inline script
 960      * somewhere on this page.
 961      *
 962      * By default the call will be put in a script tag at the
 963      * end of the page after initialising Y instance, since this gives best page-load
 964      * performance and allows you to use YUI3 library.
 965      *
 966      * If you request that a particular function is called several times, then
 967      * that is what will happen (unlike linking to a CSS or JS file, where only
 968      * one link will be output).
 969      *
 970      * The main benefit of the method is the automatic encoding of all function parameters.
 971      *
 972      * @deprecated
 973      *
 974      * @param string $function the name of the JavaScritp function to call. Can
 975      *      be a compound name like 'Y.Event.purgeElement'. Can also be
 976      *      used to create and object by using a 'function name' like 'new user_selector'.
 977      * @param array $arguments and array of arguments to be passed to the function.
 978      *      When generating the function call, this will be escaped using json_encode,
 979      *      so passing objects and arrays should work.
 980      * @param bool $ondomready If tru the function is only called when the dom is
 981      *      ready for manipulation.
 982      * @param int $delay The delay before the function is called.
 983      */
 984     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
 985         $where = $ondomready ? 'ondomready' : 'normal';
 986         $this->jscalls[$where][] = array($function, $arguments, $delay);
 987     }
 988
 989     /**
 990      * This function appends a block of code to the AMD specific javascript block executed
 991      * in the page footer, just after loading the requirejs library.
 992      *
 993      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
 994      *
 995      * @param string $code The JS code to append.
 996      */
 997     public function js_amd_inline($code) {
 998         $this->amdjscode[] = $code;
 999     }
1000
1001     /**
1002      * This function creates a minimal JS script that requires and calls a single function from an AMD module with arguments.
1003      * If it is called multiple times, it will be executed multiple times.
1004      *
1005      * @param string $fullmodule The format for module names is <component name>/<module name>.
1006      * @param string $func The function from the module to call
1007      * @param array $params The params to pass to the function. They will be json encoded, so no nasty classes/types please.
1008      */
1009     public function js_call_amd($fullmodule, $func, $params = array()) {
1010         global $CFG;
1011
1012         list($component, $module) = explode('/', $fullmodule, 2);
1013
1014         $component = clean_param($component, PARAM_COMPONENT);
1015         $module = clean_param($module, PARAM_ALPHANUMEXT);
1016         $func = clean_param($func, PARAM_ALPHANUMEXT);
1017
1018         $modname = "{$component}/{$module}";
1019
1020         $jsonparams = array();
1021         foreach ($params as $param) {
1022             $jsonparams[] = json_encode($param);
1023         }
1024         $strparams = implode(', ', $jsonparams);
1025         if ($CFG->debugdeveloper) {
1026             $toomanyparamslimit = 1024;
1027             if (strlen($strparams) > $toomanyparamslimit) {
1028                 debugging('Too much data passed as arguments to js_call_amd("' . $fullmodule . '", "' . $func .
1029                         '"). Generally there are better ways to pass lots of data from PHP to JavaScript, for example via Ajax, data attributes, ... . ' .
1030                         'This warning is triggered if the argument string becomes longer than ' . $toomanyparamslimit . ' characters.', DEBUG_DEVELOPER);
1031             }
1032
1033         }
1034         $js = <<<EOF
1035 M.util.js_pending('{$modname}');
1036 require(['{$modname}'], function(amd) {
1037     amd.{$func}({$strparams});
1038     M.util.js_complete('{$modname}');
1039 });
1040 EOF;
1041
1042         $this->js_amd_inline($js);
1043     }
1044
1045     /**
1046      * Creates a JavaScript function call that requires one or more modules to be loaded.
1047      *
1048      * This function can be used to include all of the standard YUI module types within JavaScript:
1049      *     - YUI3 modules    [node, event, io]
1050      *     - YUI2 modules    [yui2-*]
1051      *     - Moodle modules  [moodle-*]
1052      *     - Gallery modules [gallery-*]
1053      *
1054      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1055      * @see js_call_amd()
1056      *
1057      * @param array|string $modules One or more modules
1058      * @param string $function The function to call once modules have been loaded
1059      * @param array $arguments An array of arguments to pass to the function
1060      * @param string $galleryversion Deprecated: The gallery version to use
1061      * @param bool $ondomready
1062      */
1063     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1064         if (!is_array($modules)) {
1065             $modules = array($modules);
1066         }
1067
1068         if ($galleryversion != null) {
1069             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1070         }
1071
1072         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1073         if ($ondomready) {
1074             $jscode = "Y.on('domready', function() { $jscode });";
1075         }
1076         $this->jsinitcode[] = $jscode;
1077     }
1078
1079     /**
1080      * Set the CSS Modules to be included from YUI.
1081      *
1082      * @param array $modules The list of YUI CSS Modules to include.
1083      */
1084     public function set_yuicssmodules(array $modules = array()) {
1085         $this->yuicssmodules = $modules;
1086     }
1087
1088     /**
1089      * Ensure that the specified JavaScript function is called from an inline script
1090      * from page footer.
1091      *
1092      * @param string $function the name of the JavaScritp function to with init code,
1093      *      usually something like 'M.mod_mymodule.init'
1094      * @param array $extraarguments and array of arguments to be passed to the function.
1095      *      The first argument is always the YUI3 Y instance with all required dependencies
1096      *      already loaded.
1097      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1098      * @param array $module JS module specification array
1099      */
1100     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1101         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1102         if (!$module) {
1103             // Detect module automatically.
1104             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1105                 $module = $this->find_module($matches[1]);
1106             }
1107         }
1108
1109         $this->js_init_code($jscode, $ondomready, $module);
1110     }
1111
1112     /**
1113      * Add short static javascript code fragment to page footer.
1114      * This is intended primarily for loading of js modules and initialising page layout.
1115      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1116      * may override it.
1117      *
1118      * @param string $jscode
1119      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1120      * @param array $module JS module specification array
1121      */
1122     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1123         $jscode = trim($jscode, " ;\n"). ';';
1124
1125         $uniqid = html_writer::random_id();
1126         $startjs = " M.util.js_pending('" . $uniqid . "');";
1127         $endjs = " M.util.js_complete('" . $uniqid . "');";
1128
1129         if ($module) {
1130             $this->js_module($module);
1131             $modulename = $module['name'];
1132             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1133         }
1134
1135         if ($ondomready) {
1136             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1137         }
1138
1139         $this->jsinitcode[] = $jscode;
1140     }
1141
1142     /**
1143      * Make a language string available to JavaScript.
1144      *
1145      * All the strings will be available in a M.str object in the global namespace.
1146      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1147      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1148      * equivalent in the current language.
1149      *
1150      * The arguments to this function are just like the arguments to get_string
1151      * except that $component is not optional, and there are some aspects to consider
1152      * when the string contains {$a} placeholder.
1153      *
1154      * If the string does not contain any {$a} placeholder, you can simply use
1155      * M.str.component.identifier to obtain it. If you prefer, you can call
1156      * M.util.get_string(identifier, component) to get the same result.
1157      *
1158      * If you need to use {$a} placeholders, there are two options. Either the
1159      * placeholder should be substituted in PHP on server side or it should
1160      * be substituted in Javascript at client side.
1161      *
1162      * To substitute the placeholder at server side, just provide the required
1163      * value for the placeholder when you require the string. Because each string
1164      * is only stored once in the JavaScript (based on $identifier and $module)
1165      * you cannot get the same string with two different values of $a. If you try,
1166      * an exception will be thrown. Once the placeholder is substituted, you can
1167      * use M.str or M.util.get_string() as shown above:
1168      *
1169      *     // Require the string in PHP and replace the placeholder.
1170      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1171      *     // Use the result of the substitution in Javascript.
1172      *     alert(M.str.moodle.fullnamedisplay);
1173      *
1174      * To substitute the placeholder at client side, use M.util.get_string()
1175      * function. It implements the same logic as {@link get_string()}:
1176      *
1177      *     // Require the string in PHP but keep {$a} as it is.
1178      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1179      *     // Provide the values on the fly in Javascript.
1180      *     user = { firstname : 'Harry', lastname : 'Potter' }
1181      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1182      *
1183      * If you do need the same string expanded with different $a values in PHP
1184      * on server side, then the solution is to put them in your own data structure
1185      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1186      *
1187      * @param string $identifier the desired string.
1188      * @param string $component the language file to look in.
1189      * @param mixed $a any extra data to add into the string (optional).
1190      */
1191     public function string_for_js($identifier, $component, $a = null) {
1192         if (!$component) {
1193             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1194         }
1195         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1196             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1197                     "from lang file '$component' with different \$a parameter?");
1198         }
1199         if (!isset($this->stringsforjs[$component][$identifier])) {
1200             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1201             $this->stringsforjs_as[$component][$identifier] = $a;
1202         }
1203     }
1204
1205     /**
1206      * Make an array of language strings available for JS.
1207      *
1208      * This function calls the above function {@link string_for_js()} for each requested
1209      * string in the $identifiers array that is passed to the argument for a single module
1210      * passed in $module.
1211      *
1212      * <code>
1213      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1214      *
1215      * // The above is identical to calling:
1216      *
1217      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1218      * $PAGE->requires->string_for_js('two', 'mymod');
1219      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1220      * </code>
1221      *
1222      * @param array $identifiers An array of desired strings
1223      * @param string $component The module to load for
1224      * @param mixed $a This can either be a single variable that gets passed as extra
1225      *         information for every string or it can be an array of mixed data where the
1226      *         key for the data matches that of the identifier it is meant for.
1227      *
1228      */
1229     public function strings_for_js($identifiers, $component, $a = null) {
1230         foreach ($identifiers as $key => $identifier) {
1231             if (is_array($a) && array_key_exists($key, $a)) {
1232                 $extra = $a[$key];
1233             } else {
1234                 $extra = $a;
1235             }
1236             $this->string_for_js($identifier, $component, $extra);
1237         }
1238     }
1239
1240     /**
1241      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1242      *
1243      * Make some data from PHP available to JavaScript code.
1244      *
1245      * For example, if you call
1246      * <pre>
1247      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1248      * </pre>
1249      * then in JavsScript mydata.name will be 'Moodle'.
1250      *
1251      * @deprecated
1252      * @param string $variable the the name of the JavaScript variable to assign the data to.
1253      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1254      *      should be considered an experimental feature.
1255      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1256      *      so passing objects and arrays should work.
1257      * @param bool $inhead initialise in head
1258      * @return void
1259      */
1260     public function data_for_js($variable, $data, $inhead=false) {
1261         $where = $inhead ? 'head' : 'footer';
1262         $this->jsinitvariables[$where][] = array($variable, $data);
1263     }
1264
1265     /**
1266      * Creates a YUI event handler.
1267      *
1268      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1269      * @param string $event A valid DOM event (click, mousedown, change etc.)
1270      * @param string $function The name of the function to call
1271      * @param array  $arguments An optional array of argument parameters to pass to the function
1272      */
1273     public function event_handler($selector, $event, $function, array $arguments = null) {
1274         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1275     }
1276
1277     /**
1278      * Returns code needed for registering of event handlers.
1279      * @return string JS code
1280      */
1281     protected function get_event_handler_code() {
1282         $output = '';
1283         foreach ($this->eventhandlers as $h) {
1284             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1285         }
1286         return $output;
1287     }
1288
1289     /**
1290      * Get the inline JavaScript code that need to appear in a particular place.
1291      * @param bool $ondomready
1292      * @return string
1293      */
1294     protected function get_javascript_code($ondomready) {
1295         $where = $ondomready ? 'ondomready' : 'normal';
1296         $output = '';
1297         if ($this->jscalls[$where]) {
1298             foreach ($this->jscalls[$where] as $data) {
1299                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1300             }
1301             if (!empty($ondomready)) {
1302                 $output = "    Y.on('domready', function() {\n$output\n});";
1303             }
1304         }
1305         return $output;
1306     }
1307
1308     /**
1309      * Returns js code to be executed when Y is available.
1310      * @return string
1311      */
1312     protected function get_javascript_init_code() {
1313         if (count($this->jsinitcode)) {
1314             return implode("\n", $this->jsinitcode) . "\n";
1315         }
1316         return '';
1317     }
1318
1319     /**
1320      * Returns js code to load amd module loader, then insert inline script tags
1321      * that contain require() calls using RequireJS.
1322      * @return string
1323      */
1324     protected function get_amd_footercode() {
1325         global $CFG;
1326         $output = '';
1327         $jsrev = $this->get_jsrev();
1328
1329         $jsloader = new moodle_url('/lib/javascript.php');
1330         $jsloader->set_slashargument('/' . $jsrev . '/');
1331         $requirejsloader = new moodle_url('/lib/requirejs.php');
1332         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1333
1334         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1335
1336         // No extension required unless slash args is disabled.
1337         $jsextension = '.js';
1338         if (!empty($CFG->slasharguments)) {
1339             $jsextension = '';
1340         }
1341
1342         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1343         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1344         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1345
1346         $output .= html_writer::script($requirejsconfig);
1347         if ($CFG->debugdeveloper) {
1348             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1349         } else {
1350             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1351         }
1352
1353         // First include must be to a module with no dependencies, this prevents multiple requests.
1354         $prefix = 'M.util.js_pending("core/first");';
1355         $prefix .= "require(['core/first'], function() {\n";
1356         $suffix = 'M.util.js_complete("core/first");';
1357         $suffix .= "\n});";
1358         $output .= html_writer::script($prefix . implode(";\n", $this->amdjscode) . $suffix);
1359         return $output;
1360     }
1361
1362     /**
1363      * Returns basic YUI3 CSS code.
1364      *
1365      * @return string
1366      */
1367     protected function get_yui3lib_headcss() {
1368         global $CFG;
1369
1370         $yuiformat = '-min';
1371         if ($this->yui3loader->filter === 'RAW') {
1372             $yuiformat = '';
1373         }
1374
1375         $code = '';
1376         if ($this->yui3loader->combine) {
1377             if (!empty($this->yuicssmodules)) {
1378                 $modules = array();
1379                 foreach ($this->yuicssmodules as $module) {
1380                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1381                 }
1382                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1383             }
1384             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1385
1386         } else {
1387             if (!empty($this->yuicssmodules)) {
1388                 foreach ($this->yuicssmodules as $module) {
1389                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1390                 }
1391             }
1392             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1393         }
1394
1395         if ($this->yui3loader->filter === 'RAW') {
1396             $code = str_replace('-min.css', '.css', $code);
1397         } else if ($this->yui3loader->filter === 'DEBUG') {
1398             $code = str_replace('-min.css', '.css', $code);
1399         }
1400         return $code;
1401     }
1402
1403     /**
1404      * Returns basic YUI3 JS loading code.
1405      *
1406      * @return string
1407      */
1408     protected function get_yui3lib_headcode() {
1409         global $CFG;
1410
1411         $jsrev = $this->get_jsrev();
1412
1413         $yuiformat = '-min';
1414         if ($this->yui3loader->filter === 'RAW') {
1415             $yuiformat = '';
1416         }
1417
1418         $format = '-min';
1419         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1420             $format = '-debug';
1421         }
1422
1423         $rollupversion = $CFG->yui3version;
1424         if (!empty($CFG->yuipatchlevel)) {
1425             $rollupversion .= '_' . $CFG->yuipatchlevel;
1426         }
1427
1428         $baserollups = array(
1429             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1430         );
1431
1432         if ($this->yui3loader->combine) {
1433             return '<script type="text/javascript" src="' .
1434                     $this->yui3loader->local_comboBase .
1435                     implode('&amp;', $baserollups) .
1436                     '"></script>';
1437         } else {
1438             $code = '';
1439             foreach ($baserollups as $rollup) {
1440                 $code .= '<script type="text/javascript" src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1441             }
1442             return $code;
1443         }
1444
1445     }
1446
1447     /**
1448      * Returns html tags needed for inclusion of theme CSS.
1449      *
1450      * @return string
1451      */
1452     protected function get_css_code() {
1453         // First of all the theme CSS, then any custom CSS
1454         // Please note custom CSS is strongly discouraged,
1455         // because it can not be overridden by themes!
1456         // It is suitable only for things like mod/data which accepts CSS from teachers.
1457         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1458
1459         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1460         $code = $this->get_yui3lib_headcss();
1461
1462         // This line of code may look funny but it is currently required in order
1463         // to avoid MASSIVE display issues in Internet Explorer.
1464         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1465         // ignored whenever another resource is added until such time as a redraw
1466         // is forced, usually by moving the mouse over the affected element.
1467         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1468
1469         $urls = $this->cssthemeurls + $this->cssurls;
1470         foreach ($urls as $url) {
1471             $attributes['href'] = $url;
1472             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1473             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1474             unset($attributes['id']);
1475         }
1476
1477         return $code;
1478     }
1479
1480     /**
1481      * Adds extra modules specified after printing of page header.
1482      *
1483      * @return string
1484      */
1485     protected function get_extra_modules_code() {
1486         if (empty($this->extramodules)) {
1487             return '';
1488         }
1489         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1490     }
1491
1492     /**
1493      * Generate any HTML that needs to go inside the <head> tag.
1494      *
1495      * Normally, this method is called automatically by the code that prints the
1496      * <head> tag. You should not normally need to call it in your own code.
1497      *
1498      * @param moodle_page $page
1499      * @param core_renderer $renderer
1500      * @return string the HTML code to to inside the <head> tag.
1501      */
1502     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1503         global $CFG;
1504
1505         // Note: the $page and $output are not stored here because it would
1506         // create circular references in memory which prevents garbage collection.
1507         $this->init_requirements_data($page, $renderer);
1508
1509         $output = '';
1510
1511         // Add all standard CSS for this page.
1512         $output .= $this->get_css_code();
1513
1514         // Set up the M namespace.
1515         $js = "var M = {}; M.yui = {};\n";
1516
1517         // Capture the time now ASAP during page load. This minimises the lag when
1518         // we try to relate times on the server to times in the browser.
1519         // An example of where this is used is the quiz countdown timer.
1520         $js .= "M.pageloadstarttime = new Date();\n";
1521
1522         // Add a subset of Moodle configuration to the M namespace.
1523         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1524
1525         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1526         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1527         //       this needs to be done before including any other script.
1528         $js .= $this->YUI_config->get_config_functions();
1529         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1530         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1531         $js = $this->YUI_config->update_header_js($js);
1532
1533         $output .= html_writer::script($js);
1534
1535         // Add variables.
1536         if ($this->jsinitvariables['head']) {
1537             $js = '';
1538             foreach ($this->jsinitvariables['head'] as $data) {
1539                 list($var, $value) = $data;
1540                 $js .= js_writer::set_variable($var, $value, true);
1541             }
1542             $output .= html_writer::script($js);
1543         }
1544
1545         // Mark head sending done, it is not possible to anything there.
1546         $this->headdone = true;
1547
1548         return $output;
1549     }
1550
1551     /**
1552      * Generate any HTML that needs to go at the start of the <body> tag.
1553      *
1554      * Normally, this method is called automatically by the code that prints the
1555      * <head> tag. You should not normally need to call it in your own code.
1556      *
1557      * @param renderer_base $renderer
1558      * @return string the HTML code to go at the start of the <body> tag.
1559      */
1560     public function get_top_of_body_code(renderer_base $renderer) {
1561         // First the skip links.
1562         $output = $renderer->render_skip_links($this->skiplinks);
1563
1564         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1565         $output .= $this->get_yui3lib_headcode();
1566
1567         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1568         $output .= $this->get_jquery_headcode();
1569
1570         // Link our main JS file, all core stuff should be there.
1571         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1572
1573         // All the other linked things from HEAD - there should be as few as possible.
1574         if ($this->jsincludes['head']) {
1575             foreach ($this->jsincludes['head'] as $url) {
1576                 $output .= html_writer::script('', $url);
1577             }
1578         }
1579
1580         // Then the clever trick for hiding of things not needed when JS works.
1581         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1582         $this->topofbodydone = true;
1583         return $output;
1584     }
1585
1586     /**
1587      * Generate any HTML that needs to go at the end of the page.
1588      *
1589      * Normally, this method is called automatically by the code that prints the
1590      * page footer. You should not normally need to call it in your own code.
1591      *
1592      * @return string the HTML code to to at the end of the page.
1593      */
1594     public function get_end_code() {
1595         global $CFG;
1596         $output = '';
1597
1598         // Set the log level for the JS logging.
1599         $logconfig = new stdClass();
1600         $logconfig->level = 'warn';
1601         if ($CFG->debugdeveloper) {
1602             $logconfig->level = 'trace';
1603         }
1604         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1605
1606         // Call amd init functions.
1607         $output .= $this->get_amd_footercode();
1608
1609         // Add other requested modules.
1610         $output .= $this->get_extra_modules_code();
1611
1612         $this->js_init_code('M.util.js_complete("init");', true);
1613
1614         // All the other linked scripts - there should be as few as possible.
1615         if ($this->jsincludes['footer']) {
1616             foreach ($this->jsincludes['footer'] as $url) {
1617                 $output .= html_writer::script('', $url);
1618             }
1619         }
1620
1621         // Add all needed strings.
1622         // First add core strings required for some dialogues.
1623         $this->strings_for_js(array(
1624             'confirm',
1625             'yes',
1626             'no',
1627             'areyousure',
1628             'closebuttontitle',
1629             'unknownerror',
1630         ), 'moodle');
1631         if (!empty($this->stringsforjs)) {
1632             $strings = array();
1633             foreach ($this->stringsforjs as $component=>$v) {
1634                 foreach($v as $indentifier => $langstring) {
1635                     $strings[$component][$indentifier] = $langstring->out();
1636                 }
1637             }
1638             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1639         }
1640
1641         // Add variables.
1642         if ($this->jsinitvariables['footer']) {
1643             $js = '';
1644             foreach ($this->jsinitvariables['footer'] as $data) {
1645                 list($var, $value) = $data;
1646                 $js .= js_writer::set_variable($var, $value, true);
1647             }
1648             $output .= html_writer::script($js);
1649         }
1650
1651         $inyuijs = $this->get_javascript_code(false);
1652         $ondomreadyjs = $this->get_javascript_code(true);
1653         $jsinit = $this->get_javascript_init_code();
1654         $handlersjs = $this->get_event_handler_code();
1655
1656         // There is a global Y, make sure it is available in your scope.
1657         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1658
1659         $output .= html_writer::script($js);
1660
1661         return $output;
1662     }
1663
1664     /**
1665      * Have we already output the code in the <head> tag?
1666      *
1667      * @return bool
1668      */
1669     public function is_head_done() {
1670         return $this->headdone;
1671     }
1672
1673     /**
1674      * Have we already output the code at the start of the <body> tag?
1675      *
1676      * @return bool
1677      */
1678     public function is_top_of_body_done() {
1679         return $this->topofbodydone;
1680     }
1681
1682     /**
1683      * Should we generate a bit of content HTML that is only required once  on
1684      * this page (e.g. the contents of the modchooser), now? Basically, we call
1685      * {@link has_one_time_item_been_created()}, and if the thing has not already
1686      * been output, we return true to tell the caller to generate it, and also
1687      * call {@link set_one_time_item_created()} to record the fact that it is
1688      * about to be generated.
1689      *
1690      * That is, a typical usage pattern (in a renderer method) is:
1691      * <pre>
1692      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1693      *     return '';
1694      * }
1695      * // Else generate it.
1696      * </pre>
1697      *
1698      * @param string $thing identifier for the bit of content. Should be of the form
1699      *      frankenstyle_things, e.g. core_course_modchooser.
1700      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1701      */
1702     public function should_create_one_time_item_now($thing) {
1703         if ($this->has_one_time_item_been_created($thing)) {
1704             return false;
1705         }
1706
1707         $this->set_one_time_item_created($thing);
1708         return true;
1709     }
1710
1711     /**
1712      * Has a particular bit of HTML that is only required once  on this page
1713      * (e.g. the contents of the modchooser) already been generated?
1714      *
1715      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1716      * method rather than calling this method directly.
1717      *
1718      * @param string $thing identifier for the bit of content. Should be of the form
1719      *      frankenstyle_things, e.g. core_course_modchooser.
1720      * @return bool whether that bit of output has been created.
1721      */
1722     public function has_one_time_item_been_created($thing) {
1723         return isset($this->onetimeitemsoutput[$thing]);
1724     }
1725
1726     /**
1727      * Indicate that a particular bit of HTML that is only required once on this
1728      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1729      *
1730      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1731      * method rather than calling this method directly.
1732      *
1733      * @param string $thing identifier for the bit of content. Should be of the form
1734      *      frankenstyle_things, e.g. core_course_modchooser.
1735      */
1736     public function set_one_time_item_created($thing) {
1737         if ($this->has_one_time_item_been_created($thing)) {
1738             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1739                     'once per page, but it seems to be being output again.');
1740         }
1741         return $this->onetimeitemsoutput[$thing] = true;
1742     }
1743 }
1744
1745 /**
1746  * This class represents the YUI configuration.
1747  *
1748  * @copyright 2013 Andrew Nicols
1749  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1750  * @since Moodle 2.5
1751  * @package core
1752  * @category output
1753  */
1754 class YUI_config {
1755     /**
1756      * These settings must be public so that when the object is converted to json they are exposed.
1757      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1758      *
1759      * The settings are described and documented in the YUI API at:
1760      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1761      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1762      */
1763     public $debug = false;
1764     public $base;
1765     public $comboBase;
1766     public $combine;
1767     public $filter = null;
1768     public $insertBefore = 'firstthemesheet';
1769     public $groups = array();
1770     public $modules = array();
1771
1772     /**
1773      * @var array List of functions used by the YUI Loader group pattern recognition.
1774      */
1775     protected $jsconfigfunctions = array();
1776
1777     /**
1778      * Create a new group within the YUI_config system.
1779      *
1780      * @param String $name The name of the group. This must be unique and
1781      * not previously used.
1782      * @param Array $config The configuration for this group.
1783      * @return void
1784      */
1785     public function add_group($name, $config) {
1786         if (isset($this->groups[$name])) {
1787             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1788         }
1789         $this->groups[$name] = $config;
1790     }
1791
1792     /**
1793      * Update an existing group configuration
1794      *
1795      * Note, any existing configuration for that group will be wiped out.
1796      * This includes module configuration.
1797      *
1798      * @param String $name The name of the group. This must be unique and
1799      * not previously used.
1800      * @param Array $config The configuration for this group.
1801      * @return void
1802      */
1803     public function update_group($name, $config) {
1804         if (!isset($this->groups[$name])) {
1805             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.');
1806         }
1807         $this->groups[$name] = $config;
1808     }
1809
1810     /**
1811      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1812      *
1813      * Only the body of the function should be passed, and not the whole function wrapper.
1814      *
1815      * The JS function your write will be passed a single argument 'name' containing the
1816      * name of the module being loaded.
1817      *
1818      * @param $function String the body of the JavaScript function. This should be used i
1819      * @return String the name of the function to use in the group pattern configuration.
1820      */
1821     public function set_config_function($function) {
1822         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1823         if (isset($this->jsconfigfunctions[$configname])) {
1824             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1825         }
1826         $this->jsconfigfunctions[$configname] = $function;
1827         return '@' . $configname . '@';
1828     }
1829
1830     /**
1831      * Allow setting of the config function described in {@see set_config_function} from a file.
1832      * The contents of this file are then passed to set_config_function.
1833      *
1834      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1835      *
1836      * @param $file The path to the JavaScript function used for YUI configuration.
1837      * @return String the name of the function to use in the group pattern configuration.
1838      */
1839     public function set_config_source($file) {
1840         global $CFG;
1841         $cache = cache::make('core', 'yuimodules');
1842
1843         // Attempt to get the metadata from the cache.
1844         $keyname = 'configfn_' . $file;
1845         $fullpath = $CFG->dirroot . '/' . $file;
1846         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1847             $cache->delete($keyname);
1848             $configfn = file_get_contents($fullpath);
1849         } else {
1850             $configfn = $cache->get($keyname);
1851             if ($configfn === false) {
1852                 require_once($CFG->libdir . '/jslib.php');
1853                 $configfn = core_minify::js_files(array($fullpath));
1854                 $cache->set($keyname, $configfn);
1855             }
1856         }
1857         return $this->set_config_function($configfn);
1858     }
1859
1860     /**
1861      * Retrieve the list of JavaScript functions for YUI_config groups.
1862      *
1863      * @return String The complete set of config functions
1864      */
1865     public function get_config_functions() {
1866         $configfunctions = '';
1867         foreach ($this->jsconfigfunctions as $functionname => $function) {
1868             $configfunctions .= "var {$functionname} = function(me) {";
1869             $configfunctions .= $function;
1870             $configfunctions .= "};\n";
1871         }
1872         return $configfunctions;
1873     }
1874
1875     /**
1876      * Update the header JavaScript with any required modification for the YUI Loader.
1877      *
1878      * @param $js String The JavaScript to manipulate.
1879      * @return String the modified JS string.
1880      */
1881     public function update_header_js($js) {
1882         // Update the names of the the configFn variables.
1883         // The PHP json_encode function cannot handle literal names so we have to wrap
1884         // them in @ and then replace them with literals of the same function name.
1885         foreach ($this->jsconfigfunctions as $functionname => $function) {
1886             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1887         }
1888         return $js;
1889     }
1890
1891     /**
1892      * Add configuration for a specific module.
1893      *
1894      * @param String $name The name of the module to add configuration for.
1895      * @param Array $config The configuration for the specified module.
1896      * @param String $group The name of the group to add configuration for.
1897      * If not specified, then this module is added to the global
1898      * configuration.
1899      * @return void
1900      */
1901     public function add_module_config($name, $config, $group = null) {
1902         if ($group) {
1903             if (!isset($this->groups[$name])) {
1904                 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.');
1905             }
1906             if (!isset($this->groups[$group]['modules'])) {
1907                 $this->groups[$group]['modules'] = array();
1908             }
1909             $modules = &$this->groups[$group]['modules'];
1910         } else {
1911             $modules = &$this->modules;
1912         }
1913         $modules[$name] = $config;
1914     }
1915
1916     /**
1917      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
1918      *
1919      * If js caching is disabled, metadata will not be served causing YUI to calculate
1920      * module dependencies as each module is loaded.
1921      *
1922      * If metadata does not exist it will be created and stored in a MUC entry.
1923      *
1924      * @return void
1925      */
1926     public function add_moodle_metadata() {
1927         global $CFG;
1928         if (!isset($this->groups['moodle'])) {
1929             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.');
1930         }
1931
1932         if (!isset($this->groups['moodle']['modules'])) {
1933             $this->groups['moodle']['modules'] = array();
1934         }
1935
1936         $cache = cache::make('core', 'yuimodules');
1937         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1938             $metadata = array();
1939             $metadata = $this->get_moodle_metadata();
1940             $cache->delete('metadata');
1941         } else {
1942             // Attempt to get the metadata from the cache.
1943             if (!$metadata = $cache->get('metadata')) {
1944                 $metadata = $this->get_moodle_metadata();
1945                 $cache->set('metadata', $metadata);
1946             }
1947         }
1948
1949         // Merge with any metadata added specific to this page which was added manually.
1950         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
1951                 $metadata);
1952     }
1953
1954     /**
1955      * Determine the module metadata for all moodle YUI modules.
1956      *
1957      * This works through all modules capable of serving YUI modules, and attempts to get
1958      * metadata for each of those modules.
1959      *
1960      * @return Array of module metadata
1961      */
1962     private function get_moodle_metadata() {
1963         $moodlemodules = array();
1964         // Core isn't a plugin type or subsystem - handle it seperately.
1965         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
1966             $moodlemodules = array_merge($moodlemodules, $module);
1967         }
1968
1969         // Handle other core subsystems.
1970         $subsystems = core_component::get_core_subsystems();
1971         foreach ($subsystems as $subsystem => $path) {
1972             if (is_null($path)) {
1973                 continue;
1974             }
1975             if ($module = $this->get_moodle_path_metadata($path)) {
1976                 $moodlemodules = array_merge($moodlemodules, $module);
1977             }
1978         }
1979
1980         // And finally the plugins.
1981         $plugintypes = core_component::get_plugin_types();
1982         foreach ($plugintypes as $plugintype => $pathroot) {
1983             $pluginlist = core_component::get_plugin_list($plugintype);
1984             foreach ($pluginlist as $plugin => $path) {
1985                 if ($module = $this->get_moodle_path_metadata($path)) {
1986                     $moodlemodules = array_merge($moodlemodules, $module);
1987                 }
1988             }
1989         }
1990
1991         return $moodlemodules;
1992     }
1993
1994     /**
1995      * Helper function process and return the YUI metadata for all of the modules under the specified path.
1996      *
1997      * @param String $path the UNC path to the YUI src directory.
1998      * @return Array the complete array for frankenstyle directory.
1999      */
2000     private function get_moodle_path_metadata($path) {
2001         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
2002         $baseyui = $path . '/yui/src';
2003         $modules = array();
2004         if (is_dir($baseyui)) {
2005             $items = new DirectoryIterator($baseyui);
2006             foreach ($items as $item) {
2007                 if ($item->isDot() or !$item->isDir()) {
2008                     continue;
2009                 }
2010                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
2011                 if (!is_readable($metafile)) {
2012                     continue;
2013                 }
2014                 $metadata = file_get_contents($metafile);
2015                 $modules = array_merge($modules, (array) json_decode($metadata));
2016             }
2017         }
2018         return $modules;
2019     }
2020
2021     /**
2022      * Define YUI modules which we have been required to patch between releases.
2023      *
2024      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2025      * external CDN which will serve the true authoritative copy of the code without our patches.
2026      *
2027      * @param String combobase The local combobase
2028      * @param String yuiversion The current YUI version
2029      * @param Int patchlevel The patch level we're working to for YUI
2030      * @param Array patchedmodules An array containing the names of the patched modules
2031      * @return void
2032      */
2033     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2034         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2035         $subversion = $yuiversion . '_' . $patchlevel;
2036
2037         if ($this->comboBase == $combobase) {
2038             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2039             // loader. We just need to specify a different root which includes a slightly different YUI version number
2040             // to include our patchlevel.
2041             $patterns = array();
2042             $modules = array();
2043             foreach ($patchedmodules as $modulename) {
2044                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2045                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2046                 // loaded when the module is loaded anyway.
2047                 $patterns[$modulename] = array(
2048                     'group' => 'yui-patched',
2049                 );
2050                 $modules[$modulename] = array();
2051             }
2052
2053             // Actually add the patch group here.
2054             $this->add_group('yui-patched', array(
2055                 'combine' => true,
2056                 'root' => $subversion . '/',
2057                 'patterns' => $patterns,
2058                 'modules' => $modules,
2059             ));
2060
2061         } else {
2062             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2063             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2064             // local base in browser caches.
2065             $fullpathbase = $combobase . $subversion . '/';
2066             foreach ($patchedmodules as $modulename) {
2067                 $this->modules[$modulename] = array(
2068                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2069                 );
2070             }
2071         }
2072     }
2073 }
2074
2075 /**
2076  * Invalidate all server and client side JS caches.
2077  */
2078 function js_reset_all_caches() {
2079     global $CFG;
2080
2081     $next = time();
2082     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2083         // This resolves problems when reset is requested repeatedly within 1s,
2084         // the < 1h condition prevents accidental switching to future dates
2085         // because we might not recover from it.
2086         $next = $CFG->jsrev+1;
2087     }
2088
2089     set_config('jsrev', $next);
2090 }