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