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()) {
 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->httpswwwroot . '/lib/yuilib/'. $CFG->yui3version . '/';
 191         $this->yui3loader->local_comboBase = $CFG->httpswwwroot . '/theme/yui_combo.php'.$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->httpswwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 224             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$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->httpswwwroot . '/theme/yui_combo.php' . $sep . 'm/' . $jsrev . '/',
 239             'combine' => $this->yui3loader->combine,
 240             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$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->httpswwwroot . '/lib/yuilib/gallery/',
 254             'combine' => $this->yui3loader->combine,
 255             'comboBase' => $CFG->httpswwwroot . '/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     }
 300
 301     /**
 302      * Return the safe config values that get set for javascript in "M.cfg".
 303      *
 304      * @since 2.9
 305      * @return array List of safe config values that are available to javascript.
 306      */
 307     public function get_config_for_javascript(moodle_page $page, renderer_base $renderer) {
 308         global $CFG;
 309
 310         if (empty($this->M_cfg)) {
 311             // JavaScript should always work with $CFG->httpswwwroot rather than $CFG->wwwroot.
 312             // Otherwise, in some situations, users will get warnings about insecure content
 313             // on secure pages from their web browser.
 314
 315             $this->M_cfg = array(
 316                 'wwwroot'             => $CFG->httpswwwroot, // Yes, really. See above.
 317                 'sesskey'             => sesskey(),
 318                 'loadingicon'         => $renderer->pix_url('i/loading_small', 'moodle')->out(false),
 319                 'themerev'            => theme_get_revision(),
 320                 'slasharguments'      => (int)(!empty($CFG->slasharguments)),
 321                 'theme'               => $page->theme->name,
 322                 'jsrev'               => $this->get_jsrev(),
 323                 'admin'               => $CFG->admin,
 324                 'svgicons'            => $page->theme->use_svg_icons()
 325             );
 326             if ($CFG->debugdeveloper) {
 327                 $this->M_cfg['developerdebug'] = true;
 328             }
 329             if (defined('BEHAT_SITE_RUNNING')) {
 330                 $this->M_cfg['behatsiterunning'] = true;
 331             }
 332
 333         }
 334         return $this->M_cfg;
 335     }
 336
 337     /**
 338      * Initialise with the bits of JavaScript that every Moodle page should have.
 339      *
 340      * @param moodle_page $page
 341      * @param core_renderer $renderer
 342      */
 343     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 344         global $CFG;
 345
 346         // Init the js config.
 347         $this->get_config_for_javascript($page, $renderer);
 348
 349         // Accessibility stuff.
 350         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 351
 352         // Add strings used on many pages.
 353         $this->string_for_js('confirmation', 'admin');
 354         $this->string_for_js('cancel', 'moodle');
 355         $this->string_for_js('yes', 'moodle');
 356
 357         // Alter links in top frame to break out of frames.
 358         if ($page->pagelayout === 'frametop') {
 359             $this->js_init_call('M.util.init_frametop');
 360         }
 361
 362         // Include block drag/drop if editing is on
 363         if ($page->user_is_editing()) {
 364             $params = array(
 365                 'courseid' => $page->course->id,
 366                 'pagetype' => $page->pagetype,
 367                 'pagelayout' => $page->pagelayout,
 368                 'subpage' => $page->subpage,
 369                 'regions' => $page->blocks->get_regions(),
 370                 'contextid' => $page->context->id,
 371             );
 372             if (!empty($page->cm->id)) {
 373                 $params['cmid'] = $page->cm->id;
 374             }
 375             // Strings for drag and drop.
 376             $this->strings_for_js(array('movecontent',
 377                                         'tocontent',
 378                                         'emptydragdropregion'),
 379                                   'moodle');
 380             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 381         }
 382
 383         // Include the YUI CSS Modules.
 384         $page->requires->set_yuicssmodules($page->theme->yuicssmodules);
 385     }
 386
 387     /**
 388      * Determine the correct JS Revision to use for this load.
 389      *
 390      * @return int the jsrev to use.
 391      */
 392     protected function get_jsrev() {
 393         global $CFG;
 394
 395         if (empty($CFG->cachejs)) {
 396             $jsrev = -1;
 397         } else if (empty($CFG->jsrev)) {
 398             $jsrev = 1;
 399         } else {
 400             $jsrev = $CFG->jsrev;
 401         }
 402
 403         return $jsrev;
 404     }
 405
 406     /**
 407      * Ensure that the specified JavaScript file is linked to from this page.
 408      *
 409      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 410      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 411      *
 412      * By default the link is put at the end of the page, since this gives best page-load performance.
 413      *
 414      * Even if a particular script is requested more than once, it will only be linked
 415      * to once.
 416      *
 417      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 418      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 419      * @param bool $inhead initialise in head
 420      */
 421     public function js($url, $inhead = false) {
 422         $url = $this->js_fix_url($url);
 423         $where = $inhead ? 'head' : 'footer';
 424         $this->jsincludes[$where][$url->out()] = $url;
 425     }
 426
 427     /**
 428      * Request inclusion of jQuery library in the page.
 429      *
 430      * NOTE: this should not be used in official Moodle distribution!
 431      *
 432      * We are going to bundle jQuery 1.9.x until we drop support
 433      * all support for IE 6-8. Use $PAGE->requires->jquery_plugin('migrate')
 434      * for code written for earlier jQuery versions.
 435      *
 436      * {@see http://docs.moodle.org/dev/jQuery}
 437      */
 438     public function jquery() {
 439         $this->jquery_plugin('jquery');
 440     }
 441
 442     /**
 443      * Request inclusion of jQuery plugin.
 444      *
 445      * NOTE: this should not be used in official Moodle distribution!
 446      *
 447      * jQuery plugins are located in plugin/jquery/* subdirectory,
 448      * plugin/jquery/plugins.php lists all available plugins.
 449      *
 450      * Included core plugins:
 451      *   - jQuery UI
 452      *   - jQuery Migrate (useful for code written for previous UI version)
 453      *
 454      * Add-ons may include extra jQuery plugins in jquery/ directory,
 455      * plugins.php file defines the mapping between plugin names and
 456      * necessary page includes.
 457      *
 458      * Examples:
 459      * <code>
 460      *   // file: mod/xxx/view.php
 461      *   $PAGE->requires->jquery();
 462      *   $PAGE->requires->jquery_plugin('ui');
 463      *   $PAGE->requires->jquery_plugin('ui-css');
 464      * </code>
 465      *
 466      * <code>
 467      *   // file: theme/yyy/lib.php
 468      *   function theme_yyy_page_init(moodle_page $page) {
 469      *       $page->requires->jquery();
 470      *       $page->requires->jquery_plugin('ui');
 471      *       $page->requires->jquery_plugin('ui-css');
 472      *   }
 473      * </code>
 474      *
 475      * <code>
 476      *   // file: blocks/zzz/block_zzz.php
 477      *   public function get_required_javascript() {
 478      *       parent::get_required_javascript();
 479      *       $this->page->requires->jquery();
 480      *       $page->requires->jquery_plugin('ui');
 481      *       $page->requires->jquery_plugin('ui-css');
 482      *   }
 483      * </code>
 484      *
 485      * {@see http://docs.moodle.org/dev/jQuery}
 486      *
 487      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 488      * @param string $component name of the component
 489      * @return bool success
 490      */
 491     public function jquery_plugin($plugin, $component = 'core') {
 492         global $CFG;
 493
 494         if ($this->headdone) {
 495             debugging('Can not add jQuery plugins after starting page output!');
 496             return false;
 497         }
 498
 499         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css', 'migrate'))) {
 500             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 501             $component = 'core';
 502         } else if ($component !== 'core' and strpos($component, '_') === false) {
 503             // Let's normalise the legacy activity names, Frankenstyle rulez!
 504             $component = 'mod_' . $component;
 505         }
 506
 507         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 508             // Make sure the jQuery itself is always loaded first,
 509             // the order of all other plugins depends on order of $PAGE_>requires->.
 510             $this->jquery_plugin('jquery', 'core');
 511         }
 512
 513         if (isset($this->jqueryplugins[$plugin])) {
 514             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 515             return true;
 516         }
 517
 518         $componentdir = core_component::get_component_directory($component);
 519         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 520             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 521             return false;
 522         }
 523
 524         $plugins = array();
 525         require("$componentdir/jquery/plugins.php");
 526
 527         if (!isset($plugins[$plugin])) {
 528             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 529             return false;
 530         }
 531
 532         $this->jqueryplugins[$plugin] = new stdClass();
 533         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 534         $this->jqueryplugins[$plugin]->component = $component;
 535         $this->jqueryplugins[$plugin]->urls      = array();
 536
 537         foreach ($plugins[$plugin]['files'] as $file) {
 538             if ($CFG->debugdeveloper) {
 539                 if (!file_exists("$componentdir/jquery/$file")) {
 540                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 541                     continue;
 542                 }
 543                 $file = str_replace('.min.css', '.css', $file);
 544                 $file = str_replace('.min.js', '.js', $file);
 545             }
 546             if (!file_exists("$componentdir/jquery/$file")) {
 547                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 548                 continue;
 549             }
 550             if (!empty($CFG->slasharguments)) {
 551                 $url = new moodle_url("$CFG->httpswwwroot/theme/jquery.php");
 552                 $url->set_slashargument("/$component/$file");
 553
 554             } else {
 555                 // This is not really good, we need slasharguments for relative links, this means no caching...
 556                 $path = realpath("$componentdir/jquery/$file");
 557                 if (strpos($path, $CFG->dirroot) === 0) {
 558                     $url = $CFG->httpswwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 559                     $url = new moodle_url($url);
 560                 } else {
 561                     // Bad luck, fix your server!
 562                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 563                     continue;
 564                 }
 565             }
 566             $this->jqueryplugins[$plugin]->urls[] = $url;
 567         }
 568
 569         return true;
 570     }
 571
 572     /**
 573      * Request replacement of one jQuery plugin by another.
 574      *
 575      * This is useful when themes want to replace the jQuery UI theme,
 576      * the problem is that theme can not prevent others from including the core ui-css plugin.
 577      *
 578      * Example:
 579      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 580      *  2/ write theme/yourtheme/jquery/plugins.php
 581      *  3/ init jQuery from theme
 582      *
 583      * <code>
 584      *   // file theme/yourtheme/lib.php
 585      *   function theme_yourtheme_page_init($page) {
 586      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 587      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 588      *   }
 589      * </code>
 590      *
 591      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 592      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 593      *
 594      * {@see http://docs.moodle.org/dev/jQuery}
 595      *
 596      * @param string $oldplugin original plugin
 597      * @param string $newplugin the replacement
 598      */
 599     public function jquery_override_plugin($oldplugin, $newplugin) {
 600         if ($this->headdone) {
 601             debugging('Can not override jQuery plugins after starting page output!');
 602             return;
 603         }
 604         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 605     }
 606
 607     /**
 608      * Return jQuery related markup for page start.
 609      * @return string
 610      */
 611     protected function get_jquery_headcode() {
 612         if (empty($this->jqueryplugins['jquery'])) {
 613             // If nobody requested jQuery then do not bother to load anything.
 614             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 615             return '';
 616         }
 617
 618         $included = array();
 619         $urls = array();
 620
 621         foreach ($this->jqueryplugins as $name => $unused) {
 622             if (isset($included[$name])) {
 623                 continue;
 624             }
 625             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 626                 // The following loop tries to resolve the replacements,
 627                 // use max 100 iterations to prevent infinite loop resulting
 628                 // in blank page.
 629                 $cyclic = true;
 630                 $oldname = $name;
 631                 for ($i=0; $i<100; $i++) {
 632                     $name = $this->jquerypluginoverrides[$name];
 633                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 634                         $cyclic = false;
 635                         break;
 636                     }
 637                 }
 638                 if ($cyclic) {
 639                     // We can not do much with cyclic references here, let's use the old plugin.
 640                     $name = $oldname;
 641                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 642
 643                 } else if (empty($name)) {
 644                     // Developer requested removal of the plugin.
 645                     continue;
 646
 647                 } else if (!isset($this->jqueryplugins[$name])) {
 648                     debugging("Unknown jQuery override plugin '$name' detected");
 649                     $name = $oldname;
 650
 651                 } else if (isset($included[$name])) {
 652                     // The plugin was already included, easy.
 653                     continue;
 654                 }
 655             }
 656
 657             $plugin = $this->jqueryplugins[$name];
 658             $urls = array_merge($urls, $plugin->urls);
 659             $included[$name] = true;
 660         }
 661
 662         $output = '';
 663         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 664         foreach ($urls as $url) {
 665             if (preg_match('/\.js$/', $url)) {
 666                 $output .= html_writer::script('', $url);
 667             } else if (preg_match('/\.css$/', $url)) {
 668                 $attributes['href'] = $url;
 669                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 670             }
 671         }
 672
 673         return $output;
 674     }
 675
 676     /**
 677      * Returns the actual url through which a script is served.
 678      *
 679      * @param moodle_url|string $url full moodle url, or shortened path to script
 680      * @return moodle_url
 681      */
 682     protected function js_fix_url($url) {
 683         global $CFG;
 684
 685         if ($url instanceof moodle_url) {
 686             return $url;
 687         } else if (strpos($url, '/') === 0) {
 688             // Fix the admin links if needed.
 689             if ($CFG->admin !== 'admin') {
 690                 if (strpos($url, "/admin/") === 0) {
 691                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 692                 }
 693             }
 694             if (debugging()) {
 695                 // Check file existence only when in debug mode.
 696                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 697                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 698                 }
 699             }
 700             if (substr($url, -3) === '.js') {
 701                 $jsrev = $this->get_jsrev();
 702                 if (empty($CFG->slasharguments)) {
 703                     return new moodle_url($CFG->httpswwwroot.'/lib/javascript.php', array('rev'=>$jsrev, 'jsfile'=>$url));
 704                 } else {
 705                     $returnurl = new moodle_url($CFG->httpswwwroot.'/lib/javascript.php');
 706                     $returnurl->set_slashargument('/'.$jsrev.$url);
 707                     return $returnurl;
 708                 }
 709             } else {
 710                 return new moodle_url($CFG->httpswwwroot.$url);
 711             }
 712         } else {
 713             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 714         }
 715     }
 716
 717     /**
 718      * Find out if JS module present and return details.
 719      *
 720      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 721      * @return array description of module or null if not found
 722      */
 723     protected function find_module($component) {
 724         global $CFG, $PAGE;
 725
 726         $module = null;
 727
 728         if (strpos($component, 'core_') === 0) {
 729             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 730             // so that we do nto have to repeat the definition of these modules over and over again.
 731             switch($component) {
 732                 case 'core_filepicker':
 733                     $module = array('name'     => 'core_filepicker',
 734                                     'fullpath' => '/repository/filepicker.js',
 735                                     'requires' => array('base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form', 'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin', 'escape', 'moodle-core_filepicker'),
 736                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 737                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 738                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 739                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 740                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 741                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 742                                                         array('referencesexist', 'repository'), array('select', 'repository')
 743                                                     ));
 744                     break;
 745                 case 'core_comment':
 746                     $module = array('name'     => 'core_comment',
 747                                     'fullpath' => '/comment/comment.js',
 748                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay'),
 749                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 750                                 );
 751                     break;
 752                 case 'core_role':
 753                     $module = array('name'     => 'core_role',
 754                                     'fullpath' => '/admin/roles/module.js',
 755                                     'requires' => array('node', 'cookie'));
 756                     break;
 757                 case 'core_completion':
 758                     $module = array('name'     => 'core_completion',
 759                                     'fullpath' => '/course/completion.js');
 760                     break;
 761                 case 'core_message':
 762                     $module = array('name'     => 'core_message',
 763                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 764                                     'fullpath' => '/message/module.js');
 765                     break;
 766                 case 'core_group':
 767                     $module = array('name'     => 'core_group',
 768                                     'fullpath' => '/group/module.js',
 769                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 770                     break;
 771                 case 'core_question_engine':
 772                     $module = array('name'     => 'core_question_engine',
 773                                     'fullpath' => '/question/qengine.js',
 774                                     'requires' => array('node', 'event'));
 775                     break;
 776                 case 'core_rating':
 777                     $module = array('name'     => 'core_rating',
 778                                     'fullpath' => '/rating/module.js',
 779                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 780                     break;
 781                 case 'core_dndupload':
 782                     $module = array('name'     => 'core_dndupload',
 783                                     'fullpath' => '/lib/form/dndupload.js',
 784                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 785                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 786                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesforfile', 'moodle'),
 787                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 788                                                     ));
 789                     break;
 790             }
 791
 792         } else {
 793             if ($dir = core_component::get_component_directory($component)) {
 794                 if (file_exists("$dir/module.js")) {
 795                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 796                         $dir = substr($dir, strlen($CFG->dirroot));
 797                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 798                     }
 799                 }
 800             }
 801         }
 802
 803         return $module;
 804     }
 805
 806     /**
 807      * Append YUI3 module to default YUI3 JS loader.
 808      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 809      *
 810      * @param string|array $module name of module (details are autodetected), or full module specification as array
 811      * @return void
 812      */
 813     public function js_module($module) {
 814         global $CFG;
 815
 816         if (empty($module)) {
 817             throw new coding_exception('Missing YUI3 module name or full description.');
 818         }
 819
 820         if (is_string($module)) {
 821             $module = $this->find_module($module);
 822         }
 823
 824         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 825             throw new coding_exception('Missing YUI3 module details.');
 826         }
 827
 828         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 829         // Add all needed strings.
 830         if (!empty($module['strings'])) {
 831             foreach ($module['strings'] as $string) {
 832                 $identifier = $string[0];
 833                 $component = isset($string[1]) ? $string[1] : 'moodle';
 834                 $a = isset($string[2]) ? $string[2] : null;
 835                 $this->string_for_js($identifier, $component, $a);
 836             }
 837         }
 838         unset($module['strings']);
 839
 840         // Process module requirements and attempt to load each. This allows
 841         // moodle modules to require each other.
 842         if (!empty($module['requires'])){
 843             foreach ($module['requires'] as $requirement) {
 844                 $rmodule = $this->find_module($requirement);
 845                 if (is_array($rmodule)) {
 846                     $this->js_module($rmodule);
 847                 }
 848             }
 849         }
 850
 851         if ($this->headdone) {
 852             $this->extramodules[$module['name']] = $module;
 853         } else {
 854             $this->YUI_config->add_module_config($module['name'], $module);
 855         }
 856     }
 857
 858     /**
 859      * Returns true if the module has already been loaded.
 860      *
 861      * @param string|array $module
 862      * @return bool True if the module has already been loaded
 863      */
 864     protected function js_module_loaded($module) {
 865         if (is_string($module)) {
 866             $modulename = $module;
 867         } else {
 868             $modulename = $module['name'];
 869         }
 870         return array_key_exists($modulename, $this->YUI_config->modules) ||
 871                array_key_exists($modulename, $this->extramodules);
 872     }
 873
 874     /**
 875      * Ensure that the specified CSS file is linked to from this page.
 876      *
 877      * Because stylesheet links must go in the <head> part of the HTML, you must call
 878      * this function before {@link get_head_code()} is called. That normally means before
 879      * the call to print_header. If you call it when it is too late, an exception
 880      * will be thrown.
 881      *
 882      * Even if a particular style sheet is requested more than once, it will only
 883      * be linked to once.
 884      *
 885      * Please note use of this feature is strongly discouraged,
 886      * it is suitable only for places where CSS is submitted directly by teachers.
 887      * (Students must not be allowed to submit any external CSS because it may
 888      * contain embedded javascript!). Example of correct use is mod/data.
 889      *
 890      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 891      *   For example:
 892      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 893      */
 894     public function css($stylesheet) {
 895         global $CFG;
 896
 897         if ($this->headdone) {
 898             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 899         }
 900
 901         if ($stylesheet instanceof moodle_url) {
 902             // ok
 903         } else if (strpos($stylesheet, '/') === 0) {
 904             $stylesheet = new moodle_url($CFG->httpswwwroot.$stylesheet);
 905         } else {
 906             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 907         }
 908
 909         $this->cssurls[$stylesheet->out()] = $stylesheet;
 910     }
 911
 912     /**
 913      * Add theme stylesheet to page - do not use from plugin code,
 914      * this should be called only from the core renderer!
 915      *
 916      * @param moodle_url $stylesheet
 917      * @return void
 918      */
 919     public function css_theme(moodle_url $stylesheet) {
 920         $this->cssthemeurls[] = $stylesheet;
 921     }
 922
 923     /**
 924      * Ensure that a skip link to a given target is printed at the top of the <body>.
 925      *
 926      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 927      * will be thrown). That normally means you must call this before the call to print_header.
 928      *
 929      * If you ask for a particular skip link to be printed, it is then your responsibility
 930      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 931      * page, so that the skip link goes somewhere.
 932      *
 933      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 934      *
 935      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 936      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 937      */
 938     public function skip_link_to($target, $linktext) {
 939         if ($this->topofbodydone) {
 940             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 941             return;
 942         }
 943         $this->skiplinks[$target] = $linktext;
 944     }
 945
 946     /**
 947      * !!!DEPRECATED!!! please use js_init_call() if possible
 948      * Ensure that the specified JavaScript function is called from an inline script
 949      * somewhere on this page.
 950      *
 951      * By default the call will be put in a script tag at the
 952      * end of the page after initialising Y instance, since this gives best page-load
 953      * performance and allows you to use YUI3 library.
 954      *
 955      * If you request that a particular function is called several times, then
 956      * that is what will happen (unlike linking to a CSS or JS file, where only
 957      * one link will be output).
 958      *
 959      * The main benefit of the method is the automatic encoding of all function parameters.
 960      *
 961      * @deprecated
 962      *
 963      * @param string $function the name of the JavaScritp function to call. Can
 964      *      be a compound name like 'Y.Event.purgeElement'. Can also be
 965      *      used to create and object by using a 'function name' like 'new user_selector'.
 966      * @param array $arguments and array of arguments to be passed to the function.
 967      *      When generating the function call, this will be escaped using json_encode,
 968      *      so passing objects and arrays should work.
 969      * @param bool $ondomready If tru the function is only called when the dom is
 970      *      ready for manipulation.
 971      * @param int $delay The delay before the function is called.
 972      */
 973     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
 974         $where = $ondomready ? 'ondomready' : 'normal';
 975         $this->jscalls[$where][] = array($function, $arguments, $delay);
 976     }
 977
 978     /**
 979      * This function appends a block of code to the AMD specific javascript block executed
 980      * in the page footer, just after loading the requirejs library.
 981      *
 982      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
 983      *
 984      * @param string $code The JS code to append.
 985      */
 986     public function js_amd_inline($code) {
 987         $this->amdjscode[] = $code;
 988     }
 989
 990     /**
 991      * This function creates a minimal JS script that requires and calls a single function from an AMD module with arguments.
 992      * If it is called multiple times, it will be executed multiple times.
 993      *
 994      * @param string $fullmodule The format for module names is <component name>/<module name>.
 995      * @param string $func The function from the module to call
 996      * @param array $params The params to pass to the function. They will be json encoded, so no nasty classes/types please.
 997      */
 998     public function js_call_amd($fullmodule, $func, $params = array()) {
 999         global $CFG;
1000
1001         list($component, $module) = explode('/', $fullmodule, 2);
1002
1003         $component = clean_param($component, PARAM_COMPONENT);
1004         $module = clean_param($module, PARAM_ALPHANUMEXT);
1005         $func = clean_param($func, PARAM_ALPHANUMEXT);
1006
1007         $jsonparams = array();
1008         foreach ($params as $param) {
1009             $jsonparams[] = json_encode($param);
1010         }
1011         $strparams = implode(', ', $jsonparams);
1012         if ($CFG->debugdeveloper) {
1013             $toomanyparamslimit = 1024;
1014             if (strlen($strparams) > $toomanyparamslimit) {
1015                 debugging('Too many params passed to js_call_amd("' . $fullmodule . '", "' . $func . '")', DEBUG_DEVELOPER);
1016             }
1017         }
1018
1019         $js = 'require(["' . $component . '/' . $module . '"], function(amd) { amd.' . $func . '(' . $strparams . '); });';
1020
1021         $this->js_amd_inline($js);
1022     }
1023
1024     /**
1025      * Creates a JavaScript function call that requires one or more modules to be loaded.
1026      *
1027      * This function can be used to include all of the standard YUI module types within JavaScript:
1028      *     - YUI3 modules    [node, event, io]
1029      *     - YUI2 modules    [yui2-*]
1030      *     - Moodle modules  [moodle-*]
1031      *     - Gallery modules [gallery-*]
1032      *
1033      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1034      * @see js_call_amd()
1035      *
1036      * @param array|string $modules One or more modules
1037      * @param string $function The function to call once modules have been loaded
1038      * @param array $arguments An array of arguments to pass to the function
1039      * @param string $galleryversion Deprecated: The gallery version to use
1040      * @param bool $ondomready
1041      */
1042     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1043         if (!is_array($modules)) {
1044             $modules = array($modules);
1045         }
1046
1047         if ($galleryversion != null) {
1048             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1049         }
1050
1051         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1052         if ($ondomready) {
1053             $jscode = "Y.on('domready', function() { $jscode });";
1054         }
1055         $this->jsinitcode[] = $jscode;
1056     }
1057
1058     /**
1059      * Set the CSS Modules to be included from YUI.
1060      *
1061      * @param array $modules The list of YUI CSS Modules to include.
1062      */
1063     public function set_yuicssmodules(array $modules = array()) {
1064         $this->yuicssmodules = $modules;
1065     }
1066
1067     /**
1068      * Ensure that the specified JavaScript function is called from an inline script
1069      * from page footer.
1070      *
1071      * @param string $function the name of the JavaScritp function to with init code,
1072      *      usually something like 'M.mod_mymodule.init'
1073      * @param array $extraarguments and array of arguments to be passed to the function.
1074      *      The first argument is always the YUI3 Y instance with all required dependencies
1075      *      already loaded.
1076      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1077      * @param array $module JS module specification array
1078      */
1079     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1080         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1081         if (!$module) {
1082             // Detect module automatically.
1083             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1084                 $module = $this->find_module($matches[1]);
1085             }
1086         }
1087
1088         $this->js_init_code($jscode, $ondomready, $module);
1089     }
1090
1091     /**
1092      * Add short static javascript code fragment to page footer.
1093      * This is intended primarily for loading of js modules and initialising page layout.
1094      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1095      * may override it.
1096      *
1097      * @param string $jscode
1098      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1099      * @param array $module JS module specification array
1100      */
1101     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1102         $jscode = trim($jscode, " ;\n"). ';';
1103
1104         $uniqid = html_writer::random_id();
1105         $startjs = " M.util.js_pending('" . $uniqid . "');";
1106         $endjs = " M.util.js_complete('" . $uniqid . "');";
1107
1108         if ($module) {
1109             $this->js_module($module);
1110             $modulename = $module['name'];
1111             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1112         }
1113
1114         if ($ondomready) {
1115             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1116         }
1117
1118         $this->jsinitcode[] = $jscode;
1119     }
1120
1121     /**
1122      * Make a language string available to JavaScript.
1123      *
1124      * All the strings will be available in a M.str object in the global namespace.
1125      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1126      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1127      * equivalent in the current language.
1128      *
1129      * The arguments to this function are just like the arguments to get_string
1130      * except that $component is not optional, and there are some aspects to consider
1131      * when the string contains {$a} placeholder.
1132      *
1133      * If the string does not contain any {$a} placeholder, you can simply use
1134      * M.str.component.identifier to obtain it. If you prefer, you can call
1135      * M.util.get_string(identifier, component) to get the same result.
1136      *
1137      * If you need to use {$a} placeholders, there are two options. Either the
1138      * placeholder should be substituted in PHP on server side or it should
1139      * be substituted in Javascript at client side.
1140      *
1141      * To substitute the placeholder at server side, just provide the required
1142      * value for the placeholder when you require the string. Because each string
1143      * is only stored once in the JavaScript (based on $identifier and $module)
1144      * you cannot get the same string with two different values of $a. If you try,
1145      * an exception will be thrown. Once the placeholder is substituted, you can
1146      * use M.str or M.util.get_string() as shown above:
1147      *
1148      *     // Require the string in PHP and replace the placeholder.
1149      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1150      *     // Use the result of the substitution in Javascript.
1151      *     alert(M.str.moodle.fullnamedisplay);
1152      *
1153      * To substitute the placeholder at client side, use M.util.get_string()
1154      * function. It implements the same logic as {@link get_string()}:
1155      *
1156      *     // Require the string in PHP but keep {$a} as it is.
1157      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1158      *     // Provide the values on the fly in Javascript.
1159      *     user = { firstname : 'Harry', lastname : 'Potter' }
1160      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1161      *
1162      * If you do need the same string expanded with different $a values in PHP
1163      * on server side, then the solution is to put them in your own data structure
1164      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1165      *
1166      * @param string $identifier the desired string.
1167      * @param string $component the language file to look in.
1168      * @param mixed $a any extra data to add into the string (optional).
1169      */
1170     public function string_for_js($identifier, $component, $a = null) {
1171         if (!$component) {
1172             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1173         }
1174         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1175             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1176                     "from lang file '$component' with different \$a parameter?");
1177         }
1178         if (!isset($this->stringsforjs[$component][$identifier])) {
1179             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1180             $this->stringsforjs_as[$component][$identifier] = $a;
1181         }
1182     }
1183
1184     /**
1185      * Make an array of language strings available for JS.
1186      *
1187      * This function calls the above function {@link string_for_js()} for each requested
1188      * string in the $identifiers array that is passed to the argument for a single module
1189      * passed in $module.
1190      *
1191      * <code>
1192      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1193      *
1194      * // The above is identical to calling:
1195      *
1196      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1197      * $PAGE->requires->string_for_js('two', 'mymod');
1198      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1199      * </code>
1200      *
1201      * @param array $identifiers An array of desired strings
1202      * @param string $component The module to load for
1203      * @param mixed $a This can either be a single variable that gets passed as extra
1204      *         information for every string or it can be an array of mixed data where the
1205      *         key for the data matches that of the identifier it is meant for.
1206      *
1207      */
1208     public function strings_for_js($identifiers, $component, $a = null) {
1209         foreach ($identifiers as $key => $identifier) {
1210             if (is_array($a) && array_key_exists($key, $a)) {
1211                 $extra = $a[$key];
1212             } else {
1213                 $extra = $a;
1214             }
1215             $this->string_for_js($identifier, $component, $extra);
1216         }
1217     }
1218
1219     /**
1220      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1221      *
1222      * Make some data from PHP available to JavaScript code.
1223      *
1224      * For example, if you call
1225      * <pre>
1226      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1227      * </pre>
1228      * then in JavsScript mydata.name will be 'Moodle'.
1229      *
1230      * @deprecated
1231      * @param string $variable the the name of the JavaScript variable to assign the data to.
1232      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1233      *      should be considered an experimental feature.
1234      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1235      *      so passing objects and arrays should work.
1236      * @param bool $inhead initialise in head
1237      * @return void
1238      */
1239     public function data_for_js($variable, $data, $inhead=false) {
1240         $where = $inhead ? 'head' : 'footer';
1241         $this->jsinitvariables[$where][] = array($variable, $data);
1242     }
1243
1244     /**
1245      * Creates a YUI event handler.
1246      *
1247      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1248      * @param string $event A valid DOM event (click, mousedown, change etc.)
1249      * @param string $function The name of the function to call
1250      * @param array  $arguments An optional array of argument parameters to pass to the function
1251      */
1252     public function event_handler($selector, $event, $function, array $arguments = null) {
1253         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1254     }
1255
1256     /**
1257      * Returns code needed for registering of event handlers.
1258      * @return string JS code
1259      */
1260     protected function get_event_handler_code() {
1261         $output = '';
1262         foreach ($this->eventhandlers as $h) {
1263             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1264         }
1265         return $output;
1266     }
1267
1268     /**
1269      * Get the inline JavaScript code that need to appear in a particular place.
1270      * @param bool $ondomready
1271      * @return string
1272      */
1273     protected function get_javascript_code($ondomready) {
1274         $where = $ondomready ? 'ondomready' : 'normal';
1275         $output = '';
1276         if ($this->jscalls[$where]) {
1277             foreach ($this->jscalls[$where] as $data) {
1278                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1279             }
1280             if (!empty($ondomready)) {
1281                 $output = "    Y.on('domready', function() {\n$output\n});";
1282             }
1283         }
1284         return $output;
1285     }
1286
1287     /**
1288      * Returns js code to be executed when Y is available.
1289      * @return string
1290      */
1291     protected function get_javascript_init_code() {
1292         if (count($this->jsinitcode)) {
1293             return implode("\n", $this->jsinitcode) . "\n";
1294         }
1295         return '';
1296     }
1297
1298     /**
1299      * Returns js code to load amd module loader, then insert inline script tags
1300      * that contain require() calls using RequireJS.
1301      * @return string
1302      */
1303     protected function get_amd_footercode() {
1304         global $CFG;
1305         $output = '';
1306         $jsrev = $this->get_jsrev();
1307
1308         $jsloader = new moodle_url($CFG->httpswwwroot . '/lib/javascript.php');
1309         $jsloader->set_slashargument('/' . $jsrev . '/');
1310         $requirejsloader = new moodle_url($CFG->httpswwwroot . '/lib/requirejs.php');
1311         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1312
1313         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1314
1315         // No extension required unless slash args is disabled.
1316         $jsextension = '.js';
1317         if (!empty($CFG->slasharguments)) {
1318             $jsextension = '';
1319         }
1320
1321         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1322         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1323         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1324
1325         $output .= html_writer::script($requirejsconfig);
1326         if ($CFG->debugdeveloper) {
1327             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1328         } else {
1329             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1330         }
1331
1332         // First include must be to a module with no dependencies, this prevents multiple requests.
1333         $prefix = "require(['core/first'], function() {\n";
1334         $suffix = "\n});";
1335         $output .= html_writer::script($prefix . implode(";\n", $this->amdjscode) . $suffix);
1336         return $output;
1337     }
1338
1339     /**
1340      * Returns basic YUI3 CSS code.
1341      *
1342      * @return string
1343      */
1344     protected function get_yui3lib_headcss() {
1345         global $CFG;
1346
1347         $yuiformat = '-min';
1348         if ($this->yui3loader->filter === 'RAW') {
1349             $yuiformat = '';
1350         }
1351
1352         $code = '';
1353         if ($this->yui3loader->combine) {
1354             if (!empty($this->yuicssmodules)) {
1355                 $modules = array();
1356                 foreach ($this->yuicssmodules as $module) {
1357                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1358                 }
1359                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1360             }
1361             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1362
1363         } else {
1364             if (!empty($this->yuicssmodules)) {
1365                 foreach ($this->yuicssmodules as $module) {
1366                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1367                 }
1368             }
1369             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1370         }
1371
1372         if ($this->yui3loader->filter === 'RAW') {
1373             $code = str_replace('-min.css', '.css', $code);
1374         } else if ($this->yui3loader->filter === 'DEBUG') {
1375             $code = str_replace('-min.css', '.css', $code);
1376         }
1377         return $code;
1378     }
1379
1380     /**
1381      * Returns basic YUI3 JS loading code.
1382      *
1383      * @return string
1384      */
1385     protected function get_yui3lib_headcode() {
1386         global $CFG;
1387
1388         $jsrev = $this->get_jsrev();
1389
1390         $yuiformat = '-min';
1391         if ($this->yui3loader->filter === 'RAW') {
1392             $yuiformat = '';
1393         }
1394
1395         $format = '-min';
1396         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1397             $format = '-debug';
1398         }
1399
1400         $rollupversion = $CFG->yui3version;
1401         if (!empty($CFG->yuipatchlevel)) {
1402             $rollupversion .= '_' . $CFG->yuipatchlevel;
1403         }
1404
1405         $baserollups = array(
1406             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1407             'rollup/' . $jsrev . "/mcore{$format}.js",
1408         );
1409
1410         if ($this->yui3loader->combine) {
1411             return '<script type="text/javascript" src="' .
1412                     $this->yui3loader->local_comboBase .
1413                     implode('&amp;', $baserollups) .
1414                     '"></script>';
1415         } else {
1416             $code = '';
1417             foreach ($baserollups as $rollup) {
1418                 $code .= '<script type="text/javascript" src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1419             }
1420             return $code;
1421         }
1422
1423     }
1424
1425     /**
1426      * Returns html tags needed for inclusion of theme CSS.
1427      *
1428      * @return string
1429      */
1430     protected function get_css_code() {
1431         // First of all the theme CSS, then any custom CSS
1432         // Please note custom CSS is strongly discouraged,
1433         // because it can not be overridden by themes!
1434         // It is suitable only for things like mod/data which accepts CSS from teachers.
1435         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1436
1437         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1438         $code = $this->get_yui3lib_headcss();
1439
1440         // This line of code may look funny but it is currently required in order
1441         // to avoid MASSIVE display issues in Internet Explorer.
1442         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1443         // ignored whenever another resource is added until such time as a redraw
1444         // is forced, usually by moving the mouse over the affected element.
1445         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1446
1447         $urls = $this->cssthemeurls + $this->cssurls;
1448         foreach ($urls as $url) {
1449             $attributes['href'] = $url;
1450             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1451             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1452             unset($attributes['id']);
1453         }
1454
1455         return $code;
1456     }
1457
1458     /**
1459      * Adds extra modules specified after printing of page header.
1460      *
1461      * @return string
1462      */
1463     protected function get_extra_modules_code() {
1464         if (empty($this->extramodules)) {
1465             return '';
1466         }
1467         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1468     }
1469
1470     /**
1471      * Generate any HTML that needs to go inside the <head> tag.
1472      *
1473      * Normally, this method is called automatically by the code that prints the
1474      * <head> tag. You should not normally need to call it in your own code.
1475      *
1476      * @param moodle_page $page
1477      * @param core_renderer $renderer
1478      * @return string the HTML code to to inside the <head> tag.
1479      */
1480     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1481         global $CFG;
1482
1483         // Note: the $page and $output are not stored here because it would
1484         // create circular references in memory which prevents garbage collection.
1485         $this->init_requirements_data($page, $renderer);
1486
1487         $output = '';
1488
1489         // Add all standard CSS for this page.
1490         $output .= $this->get_css_code();
1491
1492         // Set up the M namespace.
1493         $js = "var M = {}; M.yui = {};\n";
1494
1495         // Capture the time now ASAP during page load. This minimises the lag when
1496         // we try to relate times on the server to times in the browser.
1497         // An example of where this is used is the quiz countdown timer.
1498         $js .= "M.pageloadstarttime = new Date();\n";
1499
1500         // Add a subset of Moodle configuration to the M namespace.
1501         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1502
1503         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1504         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1505         //       this needs to be done before including any other script.
1506         $js .= $this->YUI_config->get_config_functions();
1507         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1508         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1509         $js = $this->YUI_config->update_header_js($js);
1510
1511         $output .= html_writer::script($js);
1512
1513         // Add variables.
1514         if ($this->jsinitvariables['head']) {
1515             $js = '';
1516             foreach ($this->jsinitvariables['head'] as $data) {
1517                 list($var, $value) = $data;
1518                 $js .= js_writer::set_variable($var, $value, true);
1519             }
1520             $output .= html_writer::script($js);
1521         }
1522
1523         // Mark head sending done, it is not possible to anything there.
1524         $this->headdone = true;
1525
1526         return $output;
1527     }
1528
1529     /**
1530      * Generate any HTML that needs to go at the start of the <body> tag.
1531      *
1532      * Normally, this method is called automatically by the code that prints the
1533      * <head> tag. You should not normally need to call it in your own code.
1534      *
1535      * @return string the HTML code to go at the start of the <body> tag.
1536      */
1537     public function get_top_of_body_code() {
1538         // First the skip links.
1539         $links = '';
1540         $attributes = array('class' => 'skip');
1541         foreach ($this->skiplinks as $url => $text) {
1542             $attributes['data-target'] = '#'.$url;
1543             $links .= html_writer::link('#', $text, $attributes);
1544         }
1545         $output = html_writer::tag('div', $links, array('class'=>'skiplinks')) . "\n";
1546         $this->js_init_call('M.util.init_skiplink');
1547
1548         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1549         $output .= $this->get_yui3lib_headcode();
1550
1551         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1552         $output .= $this->get_jquery_headcode();
1553
1554         // Link our main JS file, all core stuff should be there.
1555         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1556
1557         // All the other linked things from HEAD - there should be as few as possible.
1558         if ($this->jsincludes['head']) {
1559             foreach ($this->jsincludes['head'] as $url) {
1560                 $output .= html_writer::script('', $url);
1561             }
1562         }
1563
1564         // Then the clever trick for hiding of things not needed when JS works.
1565         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1566         $this->topofbodydone = true;
1567         return $output;
1568     }
1569
1570     /**
1571      * Generate any HTML that needs to go at the end of the page.
1572      *
1573      * Normally, this method is called automatically by the code that prints the
1574      * page footer. You should not normally need to call it in your own code.
1575      *
1576      * @return string the HTML code to to at the end of the page.
1577      */
1578     public function get_end_code() {
1579         global $CFG;
1580         $output = '';
1581
1582         // Set the log level for the JS logging.
1583         $logconfig = new stdClass();
1584         $logconfig->level = 'warn';
1585         if ($CFG->debugdeveloper) {
1586             $logconfig->level = 'trace';
1587         }
1588         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1589
1590         // Call amd init functions.
1591         $output .= $this->get_amd_footercode();
1592
1593         // Add other requested modules.
1594         $output .= $this->get_extra_modules_code();
1595
1596         $this->js_init_code('M.util.js_complete("init");', true);
1597
1598         // All the other linked scripts - there should be as few as possible.
1599         if ($this->jsincludes['footer']) {
1600             foreach ($this->jsincludes['footer'] as $url) {
1601                 $output .= html_writer::script('', $url);
1602             }
1603         }
1604
1605         // Add all needed strings.
1606         // First add core strings required for some dialogues.
1607         $this->strings_for_js(array(
1608             'confirm',
1609             'yes',
1610             'no',
1611             'areyousure',
1612             'closebuttontitle',
1613             'unknownerror',
1614         ), 'moodle');
1615         if (!empty($this->stringsforjs)) {
1616             $strings = array();
1617             foreach ($this->stringsforjs as $component=>$v) {
1618                 foreach($v as $indentifier => $langstring) {
1619                     $strings[$component][$indentifier] = $langstring->out();
1620                 }
1621             }
1622             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1623         }
1624
1625         // Add variables.
1626         if ($this->jsinitvariables['footer']) {
1627             $js = '';
1628             foreach ($this->jsinitvariables['footer'] as $data) {
1629                 list($var, $value) = $data;
1630                 $js .= js_writer::set_variable($var, $value, true);
1631             }
1632             $output .= html_writer::script($js);
1633         }
1634
1635         $inyuijs = $this->get_javascript_code(false);
1636         $ondomreadyjs = $this->get_javascript_code(true);
1637         $jsinit = $this->get_javascript_init_code();
1638         $handlersjs = $this->get_event_handler_code();
1639
1640         // There is a global Y, make sure it is available in your scope.
1641         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1642
1643         $output .= html_writer::script($js);
1644
1645         return $output;
1646     }
1647
1648     /**
1649      * Have we already output the code in the <head> tag?
1650      *
1651      * @return bool
1652      */
1653     public function is_head_done() {
1654         return $this->headdone;
1655     }
1656
1657     /**
1658      * Have we already output the code at the start of the <body> tag?
1659      *
1660      * @return bool
1661      */
1662     public function is_top_of_body_done() {
1663         return $this->topofbodydone;
1664     }
1665
1666     /**
1667      * Should we generate a bit of content HTML that is only required once  on
1668      * this page (e.g. the contents of the modchooser), now? Basically, we call
1669      * {@link has_one_time_item_been_created()}, and if the thing has not already
1670      * been output, we return true to tell the caller to generate it, and also
1671      * call {@link set_one_time_item_created()} to record the fact that it is
1672      * about to be generated.
1673      *
1674      * That is, a typical usage pattern (in a renderer method) is:
1675      * <pre>
1676      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1677      *     return '';
1678      * }
1679      * // Else generate it.
1680      * </pre>
1681      *
1682      * @param string $thing identifier for the bit of content. Should be of the form
1683      *      frankenstyle_things, e.g. core_course_modchooser.
1684      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1685      */
1686     public function should_create_one_time_item_now($thing) {
1687         if ($this->has_one_time_item_been_created($thing)) {
1688             return false;
1689         }
1690
1691         $this->set_one_time_item_created($thing);
1692         return true;
1693     }
1694
1695     /**
1696      * Has a particular bit of HTML that is only required once  on this page
1697      * (e.g. the contents of the modchooser) already been generated?
1698      *
1699      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1700      * method rather than calling this method directly.
1701      *
1702      * @param string $thing identifier for the bit of content. Should be of the form
1703      *      frankenstyle_things, e.g. core_course_modchooser.
1704      * @return bool whether that bit of output has been created.
1705      */
1706     public function has_one_time_item_been_created($thing) {
1707         return isset($this->onetimeitemsoutput[$thing]);
1708     }
1709
1710     /**
1711      * Indicate that a particular bit of HTML that is only required once on this
1712      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1713      *
1714      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1715      * method rather than calling this method directly.
1716      *
1717      * @param string $thing identifier for the bit of content. Should be of the form
1718      *      frankenstyle_things, e.g. core_course_modchooser.
1719      */
1720     public function set_one_time_item_created($thing) {
1721         if ($this->has_one_time_item_been_created($thing)) {
1722             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1723                     'once per page, but it seems to be being output again.');
1724         }
1725         return $this->onetimeitemsoutput[$thing] = true;
1726     }
1727 }
1728
1729 /**
1730  * This class represents the YUI configuration.
1731  *
1732  * @copyright 2013 Andrew Nicols
1733  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1734  * @since Moodle 2.5
1735  * @package core
1736  * @category output
1737  */
1738 class YUI_config {
1739     /**
1740      * These settings must be public so that when the object is converted to json they are exposed.
1741      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1742      *
1743      * The settings are described and documented in the YUI API at:
1744      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1745      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1746      */
1747     public $debug = false;
1748     public $base;
1749     public $comboBase;
1750     public $combine;
1751     public $filter = null;
1752     public $insertBefore = 'firstthemesheet';
1753     public $groups = array();
1754     public $modules = array();
1755
1756     /**
1757      * @var array List of functions used by the YUI Loader group pattern recognition.
1758      */
1759     protected $jsconfigfunctions = array();
1760
1761     /**
1762      * Create a new group within the YUI_config system.
1763      *
1764      * @param String $name The name of the group. This must be unique and
1765      * not previously used.
1766      * @param Array $config The configuration for this group.
1767      * @return void
1768      */
1769     public function add_group($name, $config) {
1770         if (isset($this->groups[$name])) {
1771             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1772         }
1773         $this->groups[$name] = $config;
1774     }
1775
1776     /**
1777      * Update an existing group configuration
1778      *
1779      * Note, any existing configuration for that group will be wiped out.
1780      * This includes module configuration.
1781      *
1782      * @param String $name The name of the group. This must be unique and
1783      * not previously used.
1784      * @param Array $config The configuration for this group.
1785      * @return void
1786      */
1787     public function update_group($name, $config) {
1788         if (!isset($this->groups[$name])) {
1789             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.');
1790         }
1791         $this->groups[$name] = $config;
1792     }
1793
1794     /**
1795      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1796      *
1797      * Only the body of the function should be passed, and not the whole function wrapper.
1798      *
1799      * The JS function your write will be passed a single argument 'name' containing the
1800      * name of the module being loaded.
1801      *
1802      * @param $function String the body of the JavaScript function. This should be used i
1803      * @return String the name of the function to use in the group pattern configuration.
1804      */
1805     public function set_config_function($function) {
1806         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1807         if (isset($this->jsconfigfunctions[$configname])) {
1808             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1809         }
1810         $this->jsconfigfunctions[$configname] = $function;
1811         return '@' . $configname . '@';
1812     }
1813
1814     /**
1815      * Allow setting of the config function described in {@see set_config_function} from a file.
1816      * The contents of this file are then passed to set_config_function.
1817      *
1818      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1819      *
1820      * @param $file The path to the JavaScript function used for YUI configuration.
1821      * @return String the name of the function to use in the group pattern configuration.
1822      */
1823     public function set_config_source($file) {
1824         global $CFG;
1825         $cache = cache::make('core', 'yuimodules');
1826
1827         // Attempt to get the metadata from the cache.
1828         $keyname = 'configfn_' . $file;
1829         $fullpath = $CFG->dirroot . '/' . $file;
1830         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1831             $cache->delete($keyname);
1832             $configfn = file_get_contents($fullpath);
1833         } else {
1834             $configfn = $cache->get($keyname);
1835             if ($configfn === false) {
1836                 require_once($CFG->libdir . '/jslib.php');
1837                 $configfn = core_minify::js_files(array($fullpath));
1838                 $cache->set($keyname, $configfn);
1839             }
1840         }
1841         return $this->set_config_function($configfn);
1842     }
1843
1844     /**
1845      * Retrieve the list of JavaScript functions for YUI_config groups.
1846      *
1847      * @return String The complete set of config functions
1848      */
1849     public function get_config_functions() {
1850         $configfunctions = '';
1851         foreach ($this->jsconfigfunctions as $functionname => $function) {
1852             $configfunctions .= "var {$functionname} = function(me) {";
1853             $configfunctions .= $function;
1854             $configfunctions .= "};\n";
1855         }
1856         return $configfunctions;
1857     }
1858
1859     /**
1860      * Update the header JavaScript with any required modification for the YUI Loader.
1861      *
1862      * @param $js String The JavaScript to manipulate.
1863      * @return String the modified JS string.
1864      */
1865     public function update_header_js($js) {
1866         // Update the names of the the configFn variables.
1867         // The PHP json_encode function cannot handle literal names so we have to wrap
1868         // them in @ and then replace them with literals of the same function name.
1869         foreach ($this->jsconfigfunctions as $functionname => $function) {
1870             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1871         }
1872         return $js;
1873     }
1874
1875     /**
1876      * Add configuration for a specific module.
1877      *
1878      * @param String $name The name of the module to add configuration for.
1879      * @param Array $config The configuration for the specified module.
1880      * @param String $group The name of the group to add configuration for.
1881      * If not specified, then this module is added to the global
1882      * configuration.
1883      * @return void
1884      */
1885     public function add_module_config($name, $config, $group = null) {
1886         if ($group) {
1887             if (!isset($this->groups[$name])) {
1888                 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.');
1889             }
1890             if (!isset($this->groups[$group]['modules'])) {
1891                 $this->groups[$group]['modules'] = array();
1892             }
1893             $modules = &$this->groups[$group]['modules'];
1894         } else {
1895             $modules = &$this->modules;
1896         }
1897         $modules[$name] = $config;
1898     }
1899
1900     /**
1901      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
1902      *
1903      * If js caching is disabled, metadata will not be served causing YUI to calculate
1904      * module dependencies as each module is loaded.
1905      *
1906      * If metadata does not exist it will be created and stored in a MUC entry.
1907      *
1908      * @return void
1909      */
1910     public function add_moodle_metadata() {
1911         global $CFG;
1912         if (!isset($this->groups['moodle'])) {
1913             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.');
1914         }
1915
1916         if (!isset($this->groups['moodle']['modules'])) {
1917             $this->groups['moodle']['modules'] = array();
1918         }
1919
1920         $cache = cache::make('core', 'yuimodules');
1921         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1922             $metadata = array();
1923             $metadata = $this->get_moodle_metadata();
1924             $cache->delete('metadata');
1925         } else {
1926             // Attempt to get the metadata from the cache.
1927             if (!$metadata = $cache->get('metadata')) {
1928                 $metadata = $this->get_moodle_metadata();
1929                 $cache->set('metadata', $metadata);
1930             }
1931         }
1932
1933         // Merge with any metadata added specific to this page which was added manually.
1934         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
1935                 $metadata);
1936     }
1937
1938     /**
1939      * Determine the module metadata for all moodle YUI modules.
1940      *
1941      * This works through all modules capable of serving YUI modules, and attempts to get
1942      * metadata for each of those modules.
1943      *
1944      * @return Array of module metadata
1945      */
1946     private function get_moodle_metadata() {
1947         $moodlemodules = array();
1948         // Core isn't a plugin type or subsystem - handle it seperately.
1949         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
1950             $moodlemodules = array_merge($moodlemodules, $module);
1951         }
1952
1953         // Handle other core subsystems.
1954         $subsystems = core_component::get_core_subsystems();
1955         foreach ($subsystems as $subsystem => $path) {
1956             if (is_null($path)) {
1957                 continue;
1958             }
1959             if ($module = $this->get_moodle_path_metadata($path)) {
1960                 $moodlemodules = array_merge($moodlemodules, $module);
1961             }
1962         }
1963
1964         // And finally the plugins.
1965         $plugintypes = core_component::get_plugin_types();
1966         foreach ($plugintypes as $plugintype => $pathroot) {
1967             $pluginlist = core_component::get_plugin_list($plugintype);
1968             foreach ($pluginlist as $plugin => $path) {
1969                 if ($module = $this->get_moodle_path_metadata($path)) {
1970                     $moodlemodules = array_merge($moodlemodules, $module);
1971                 }
1972             }
1973         }
1974
1975         return $moodlemodules;
1976     }
1977
1978     /**
1979      * Helper function process and return the YUI metadata for all of the modules under the specified path.
1980      *
1981      * @param String $path the UNC path to the YUI src directory.
1982      * @return Array the complete array for frankenstyle directory.
1983      */
1984     private function get_moodle_path_metadata($path) {
1985         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
1986         $baseyui = $path . '/yui/src';
1987         $modules = array();
1988         if (is_dir($baseyui)) {
1989             $items = new DirectoryIterator($baseyui);
1990             foreach ($items as $item) {
1991                 if ($item->isDot() or !$item->isDir()) {
1992                     continue;
1993                 }
1994                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
1995                 if (!is_readable($metafile)) {
1996                     continue;
1997                 }
1998                 $metadata = file_get_contents($metafile);
1999                 $modules = array_merge($modules, (array) json_decode($metadata));
2000             }
2001         }
2002         return $modules;
2003     }
2004
2005     /**
2006      * Define YUI modules which we have been required to patch between releases.
2007      *
2008      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2009      * external CDN which will serve the true authoritative copy of the code without our patches.
2010      *
2011      * @param String combobase The local combobase
2012      * @param String yuiversion The current YUI version
2013      * @param Int patchlevel The patch level we're working to for YUI
2014      * @param Array patchedmodules An array containing the names of the patched modules
2015      * @return void
2016      */
2017     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2018         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2019         $subversion = $yuiversion . '_' . $patchlevel;
2020
2021         if ($this->comboBase == $combobase) {
2022             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2023             // loader. We just need to specify a different root which includes a slightly different YUI version number
2024             // to include our patchlevel.
2025             $patterns = array();
2026             $modules = array();
2027             foreach ($patchedmodules as $modulename) {
2028                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2029                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2030                 // loaded when the module is loaded anyway.
2031                 $patterns[$modulename] = array(
2032                     'group' => 'yui-patched',
2033                 );
2034                 $modules[$modulename] = array();
2035             }
2036
2037             // Actually add the patch group here.
2038             $this->add_group('yui-patched', array(
2039                 'combine' => true,
2040                 'root' => $subversion . '/',
2041                 'patterns' => $patterns,
2042                 'modules' => $modules,
2043             ));
2044
2045         } else {
2046             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2047             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2048             // local base in browser caches.
2049             $fullpathbase = $combobase . $subversion . '/';
2050             foreach ($patchedmodules as $modulename) {
2051                 $this->modules[$modulename] = array(
2052                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2053                 );
2054             }
2055         }
2056     }
2057 }
2058
2059 /**
2060  * Invalidate all server and client side JS caches.
2061  */
2062 function js_reset_all_caches() {
2063     global $CFG;
2064
2065     $next = time();
2066     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2067         // This resolves problems when reset is requested repeatedly within 1s,
2068         // the < 1h condition prevents accidental switching to future dates
2069         // because we might not recover from it.
2070         $next = $CFG->jsrev+1;
2071     }
2072
2073     set_config('jsrev', $next);
2074 }