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 Some config vars exposed in JS, please no secret stuff there
 153      */
 154     protected $M_cfg;
 155
 156     /**
 157      * @var array list of requested jQuery plugins
 158      */
 159     protected $jqueryplugins = array();
 160
 161     /**
 162      * @var array list of jQuery plugin overrides
 163      */
 164     protected $jquerypluginoverrides = array();
 165
 166     /**
 167      * Page requirements constructor.
 168      */
 169     public function __construct() {
 170         global $CFG;
 171
 172         // You may need to set up URL rewrite rule because oversized URLs might not be allowed by web server.
 173         $sep = empty($CFG->yuislasharguments) ? '?' : '/';
 174
 175         $this->yui3loader = new stdClass();
 176         $this->YUI_config = new YUI_config();
 177
 178         if (is_https()) {
 179             // On HTTPS sites all JS must be loaded from https sites,
 180             // YUI CDN does not support https yet, sorry.
 181             $CFG->useexternalyui = 0;
 182         }
 183
 184         // Set up some loader options.
 185         $this->yui3loader->local_base = $CFG->httpswwwroot . '/lib/yuilib/'. $CFG->yui3version . '/';
 186         $this->yui3loader->local_comboBase = $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep;
 187
 188         if (!empty($CFG->useexternalyui)) {
 189             $this->yui3loader->base = 'http://yui.yahooapis.com/' . $CFG->yui3version . '/';
 190             $this->yui3loader->comboBase = 'http://yui.yahooapis.com/combo?';
 191         } else {
 192             $this->yui3loader->base = $this->yui3loader->local_base;
 193             $this->yui3loader->comboBase = $this->yui3loader->local_comboBase;
 194         }
 195
 196         // Enable combo loader? This significantly helps with caching and performance!
 197         $this->yui3loader->combine = !empty($CFG->yuicomboloading);
 198
 199         $jsrev = $this->get_jsrev();
 200
 201         // Set up JS YUI loader helper object.
 202         $this->YUI_config->base         = $this->yui3loader->base;
 203         $this->YUI_config->comboBase    = $this->yui3loader->comboBase;
 204         $this->YUI_config->combine      = $this->yui3loader->combine;
 205
 206         // If we've had to patch any YUI modules between releases, we must override the YUI configuration to include them.
 207         // For important information on patching YUI modules, please see http://docs.moodle.org/dev/YUI/Patching.
 208         if (!empty($CFG->yuipatchedmodules) && !empty($CFG->yuipatchlevel)) {
 209             $this->YUI_config->define_patched_core_modules($this->yui3loader->local_comboBase,
 210                     $CFG->yui3version,
 211                     $CFG->yuipatchlevel,
 212                     $CFG->yuipatchedmodules);
 213         }
 214
 215         $configname = $this->YUI_config->set_config_source('lib/yui/config/yui2.js');
 216         $this->YUI_config->add_group('yui2', array(
 217             // Loader configuration for our 2in3, for now ignores $CFG->useexternalyui.
 218             'base' => $CFG->httpswwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 219             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep,
 220             'combine' => $this->yui3loader->combine,
 221             'ext' => false,
 222             'root' => '2in3/' . $CFG->yui2version .'/build/',
 223             'patterns' => array(
 224                 'yui2-' => array(
 225                     'group' => 'yui2',
 226                     'configFn' => $configname,
 227                 )
 228             )
 229         ));
 230         $configname = $this->YUI_config->set_config_source('lib/yui/config/moodle.js');
 231         $this->YUI_config->add_group('moodle', array(
 232             'name' => 'moodle',
 233             'base' => $CFG->httpswwwroot . '/theme/yui_combo.php' . $sep . 'm/' . $jsrev . '/',
 234             'combine' => $this->yui3loader->combine,
 235             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep,
 236             'ext' => false,
 237             'root' => 'm/'.$jsrev.'/', // Add the rev to the root path so that we can control caching.
 238             'patterns' => array(
 239                 'moodle-' => array(
 240                     'group' => 'moodle',
 241                     'configFn' => $configname,
 242                 )
 243             )
 244         ));
 245
 246         $this->YUI_config->add_group('gallery', array(
 247             'name' => 'gallery',
 248             'base' => $CFG->httpswwwroot . '/lib/yuilib/gallery/',
 249             'combine' => $this->yui3loader->combine,
 250             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php' . $sep,
 251             'ext' => false,
 252             'root' => 'gallery/' . $jsrev . '/',
 253             'patterns' => array(
 254                 'gallery-' => array(
 255                     'group' => 'gallery',
 256                 )
 257             )
 258         ));
 259
 260         // Set some more loader options applying to groups too.
 261         if ($CFG->debugdeveloper) {
 262             // When debugging is enabled, we want to load the non-minified (RAW) versions of YUI library modules rather
 263             // than the DEBUG versions as these generally generate too much logging for our purposes.
 264             // However we do want the DEBUG versions of our Moodle-specific modules.
 265             // To debug a YUI-specific issue, change the yui3loader->filter value to DEBUG.
 266             $this->YUI_config->filter = 'RAW';
 267             $this->YUI_config->groups['moodle']['filter'] = 'DEBUG';
 268
 269             // We use the yui3loader->filter setting when writing the YUI3 seed scripts into the header.
 270             $this->yui3loader->filter = $this->YUI_config->filter;
 271             $this->YUI_config->debug = true;
 272         } else {
 273             $this->yui3loader->filter = null;
 274             $this->YUI_config->groups['moodle']['filter'] = null;
 275             $this->YUI_config->debug = false;
 276         }
 277
 278         // Include the YUI config log filters.
 279         if (!empty($CFG->yuilogexclude) && is_array($CFG->yuilogexclude)) {
 280             $this->YUI_config->logExclude = $CFG->yuilogexclude;
 281         }
 282         if (!empty($CFG->yuiloginclude) && is_array($CFG->yuiloginclude)) {
 283             $this->YUI_config->logInclude = $CFG->yuiloginclude;
 284         }
 285         if (!empty($CFG->yuiloglevel)) {
 286             $this->YUI_config->logLevel = $CFG->yuiloglevel;
 287         }
 288
 289         // Add the moodle group's module data.
 290         $this->YUI_config->add_moodle_metadata();
 291
 292         // Every page should include definition of following modules.
 293         $this->js_module($this->find_module('core_filepicker'));
 294     }
 295
 296     /**
 297      * Return the safe config values that get set for javascript in "M.cfg".
 298      *
 299      * @since 2.9
 300      * @return array List of safe config values that are available to javascript.
 301      */
 302     public function get_config_for_javascript(moodle_page $page, renderer_base $renderer) {
 303         global $CFG;
 304
 305         if (empty($this->M_cfg)) {
 306             // JavaScript should always work with $CFG->httpswwwroot rather than $CFG->wwwroot.
 307             // Otherwise, in some situations, users will get warnings about insecure content
 308             // on secure pages from their web browser.
 309
 310             $this->M_cfg = array(
 311                 'wwwroot'             => $CFG->httpswwwroot, // Yes, really. See above.
 312                 'sesskey'             => sesskey(),
 313                 'loadingicon'         => $renderer->pix_url('i/loading_small', 'moodle')->out(false),
 314                 'themerev'            => theme_get_revision(),
 315                 'slasharguments'      => (int)(!empty($CFG->slasharguments)),
 316                 'theme'               => $page->theme->name,
 317                 'jsrev'               => $this->get_jsrev(),
 318                 'admin'               => $CFG->admin,
 319                 'svgicons'            => $page->theme->use_svg_icons()
 320             );
 321             if ($CFG->debugdeveloper) {
 322                 $this->M_cfg['developerdebug'] = true;
 323             }
 324             if (defined('BEHAT_SITE_RUNNING')) {
 325                 $this->M_cfg['behatsiterunning'] = true;
 326             }
 327
 328         }
 329         return $this->M_cfg;
 330     }
 331
 332     /**
 333      * Initialise with the bits of JavaScript that every Moodle page should have.
 334      *
 335      * @param moodle_page $page
 336      * @param core_renderer $renderer
 337      */
 338     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 339         global $CFG;
 340
 341         // Init the js config.
 342         $this->get_config_for_javascript($page, $renderer);
 343
 344         // Accessibility stuff.
 345         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 346
 347         // Add strings used on many pages.
 348         $this->string_for_js('confirmation', 'admin');
 349         $this->string_for_js('cancel', 'moodle');
 350         $this->string_for_js('yes', 'moodle');
 351
 352         // Alter links in top frame to break out of frames.
 353         if ($page->pagelayout === 'frametop') {
 354             $this->js_init_call('M.util.init_frametop');
 355         }
 356
 357         // Include block drag/drop if editing is on
 358         if ($page->user_is_editing()) {
 359             $params = array(
 360                 'courseid' => $page->course->id,
 361                 'pagetype' => $page->pagetype,
 362                 'pagelayout' => $page->pagelayout,
 363                 'subpage' => $page->subpage,
 364                 'regions' => $page->blocks->get_regions(),
 365                 'contextid' => $page->context->id,
 366             );
 367             if (!empty($page->cm->id)) {
 368                 $params['cmid'] = $page->cm->id;
 369             }
 370             // Strings for drag and drop.
 371             $this->strings_for_js(array('movecontent',
 372                                         'tocontent',
 373                                         'emptydragdropregion'),
 374                                   'moodle');
 375             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 376         }
 377     }
 378
 379     /**
 380      * Determine the correct JS Revision to use for this load.
 381      *
 382      * @return int the jsrev to use.
 383      */
 384     protected function get_jsrev() {
 385         global $CFG;
 386
 387         if (empty($CFG->cachejs)) {
 388             $jsrev = -1;
 389         } else if (empty($CFG->jsrev)) {
 390             $jsrev = 1;
 391         } else {
 392             $jsrev = $CFG->jsrev;
 393         }
 394
 395         return $jsrev;
 396     }
 397
 398     /**
 399      * Ensure that the specified JavaScript file is linked to from this page.
 400      *
 401      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 402      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 403      *
 404      * By default the link is put at the end of the page, since this gives best page-load performance.
 405      *
 406      * Even if a particular script is requested more than once, it will only be linked
 407      * to once.
 408      *
 409      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 410      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 411      * @param bool $inhead initialise in head
 412      */
 413     public function js($url, $inhead = false) {
 414         $url = $this->js_fix_url($url);
 415         $where = $inhead ? 'head' : 'footer';
 416         $this->jsincludes[$where][$url->out()] = $url;
 417     }
 418
 419     /**
 420      * Request inclusion of jQuery library in the page.
 421      *
 422      * NOTE: this should not be used in official Moodle distribution!
 423      *
 424      * We are going to bundle jQuery 1.9.x until we drop support
 425      * all support for IE 6-8. Use $PAGE->requires->jquery_plugin('migrate')
 426      * for code written for earlier jQuery versions.
 427      *
 428      * {@see http://docs.moodle.org/dev/jQuery}
 429      */
 430     public function jquery() {
 431         $this->jquery_plugin('jquery');
 432     }
 433
 434     /**
 435      * Request inclusion of jQuery plugin.
 436      *
 437      * NOTE: this should not be used in official Moodle distribution!
 438      *
 439      * jQuery plugins are located in plugin/jquery/* subdirectory,
 440      * plugin/jquery/plugins.php lists all available plugins.
 441      *
 442      * Included core plugins:
 443      *   - jQuery UI
 444      *   - jQuery Migrate (useful for code written for previous UI version)
 445      *
 446      * Add-ons may include extra jQuery plugins in jquery/ directory,
 447      * plugins.php file defines the mapping between plugin names and
 448      * necessary page includes.
 449      *
 450      * Examples:
 451      * <code>
 452      *   // file: mod/xxx/view.php
 453      *   $PAGE->requires->jquery();
 454      *   $PAGE->requires->jquery_plugin('ui');
 455      *   $PAGE->requires->jquery_plugin('ui-css');
 456      * </code>
 457      *
 458      * <code>
 459      *   // file: theme/yyy/lib.php
 460      *   function theme_yyy_page_init(moodle_page $page) {
 461      *       $page->requires->jquery();
 462      *       $page->requires->jquery_plugin('ui');
 463      *       $page->requires->jquery_plugin('ui-css');
 464      *   }
 465      * </code>
 466      *
 467      * <code>
 468      *   // file: blocks/zzz/block_zzz.php
 469      *   public function get_required_javascript() {
 470      *       parent::get_required_javascript();
 471      *       $this->page->requires->jquery();
 472      *       $page->requires->jquery_plugin('ui');
 473      *       $page->requires->jquery_plugin('ui-css');
 474      *   }
 475      * </code>
 476      *
 477      * {@see http://docs.moodle.org/dev/jQuery}
 478      *
 479      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 480      * @param string $component name of the component
 481      * @return bool success
 482      */
 483     public function jquery_plugin($plugin, $component = 'core') {
 484         global $CFG;
 485
 486         if ($this->headdone) {
 487             debugging('Can not add jQuery plugins after starting page output!');
 488             return false;
 489         }
 490
 491         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css', 'migrate'))) {
 492             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 493             $component = 'core';
 494         } else if ($component !== 'core' and strpos($component, '_') === false) {
 495             // Let's normalise the legacy activity names, Frankenstyle rulez!
 496             $component = 'mod_' . $component;
 497         }
 498
 499         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 500             // Make sure the jQuery itself is always loaded first,
 501             // the order of all other plugins depends on order of $PAGE_>requires->.
 502             $this->jquery_plugin('jquery', 'core');
 503         }
 504
 505         if (isset($this->jqueryplugins[$plugin])) {
 506             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 507             return true;
 508         }
 509
 510         $componentdir = core_component::get_component_directory($component);
 511         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 512             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 513             return false;
 514         }
 515
 516         $plugins = array();
 517         require("$componentdir/jquery/plugins.php");
 518
 519         if (!isset($plugins[$plugin])) {
 520             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 521             return false;
 522         }
 523
 524         $this->jqueryplugins[$plugin] = new stdClass();
 525         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 526         $this->jqueryplugins[$plugin]->component = $component;
 527         $this->jqueryplugins[$plugin]->urls      = array();
 528
 529         foreach ($plugins[$plugin]['files'] as $file) {
 530             if ($CFG->debugdeveloper) {
 531                 if (!file_exists("$componentdir/jquery/$file")) {
 532                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 533                     continue;
 534                 }
 535                 $file = str_replace('.min.css', '.css', $file);
 536                 $file = str_replace('.min.js', '.js', $file);
 537             }
 538             if (!file_exists("$componentdir/jquery/$file")) {
 539                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 540                 continue;
 541             }
 542             if (!empty($CFG->slasharguments)) {
 543                 $url = new moodle_url("$CFG->httpswwwroot/theme/jquery.php");
 544                 $url->set_slashargument("/$component/$file");
 545
 546             } else {
 547                 // This is not really good, we need slasharguments for relative links, this means no caching...
 548                 $path = realpath("$componentdir/jquery/$file");
 549                 if (strpos($path, $CFG->dirroot) === 0) {
 550                     $url = $CFG->httpswwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 551                     // Replace all occurences of backslashes characters in url to forward slashes.
 552                     $url = str_replace('\\', '/', $url);
 553                     $url = new moodle_url($url);
 554                 } else {
 555                     // Bad luck, fix your server!
 556                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 557                     continue;
 558                 }
 559             }
 560             $this->jqueryplugins[$plugin]->urls[] = $url;
 561         }
 562
 563         return true;
 564     }
 565
 566     /**
 567      * Request replacement of one jQuery plugin by another.
 568      *
 569      * This is useful when themes want to replace the jQuery UI theme,
 570      * the problem is that theme can not prevent others from including the core ui-css plugin.
 571      *
 572      * Example:
 573      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 574      *  2/ write theme/yourtheme/jquery/plugins.php
 575      *  3/ init jQuery from theme
 576      *
 577      * <code>
 578      *   // file theme/yourtheme/lib.php
 579      *   function theme_yourtheme_page_init($page) {
 580      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 581      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 582      *   }
 583      * </code>
 584      *
 585      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 586      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 587      *
 588      * {@see http://docs.moodle.org/dev/jQuery}
 589      *
 590      * @param string $oldplugin original plugin
 591      * @param string $newplugin the replacement
 592      */
 593     public function jquery_override_plugin($oldplugin, $newplugin) {
 594         if ($this->headdone) {
 595             debugging('Can not override jQuery plugins after starting page output!');
 596             return;
 597         }
 598         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 599     }
 600
 601     /**
 602      * Return jQuery related markup for page start.
 603      * @return string
 604      */
 605     protected function get_jquery_headcode() {
 606         if (empty($this->jqueryplugins['jquery'])) {
 607             // If nobody requested jQuery then do not bother to load anything.
 608             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 609             return '';
 610         }
 611
 612         $included = array();
 613         $urls = array();
 614
 615         foreach ($this->jqueryplugins as $name => $unused) {
 616             if (isset($included[$name])) {
 617                 continue;
 618             }
 619             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 620                 // The following loop tries to resolve the replacements,
 621                 // use max 100 iterations to prevent infinite loop resulting
 622                 // in blank page.
 623                 $cyclic = true;
 624                 $oldname = $name;
 625                 for ($i=0; $i<100; $i++) {
 626                     $name = $this->jquerypluginoverrides[$name];
 627                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 628                         $cyclic = false;
 629                         break;
 630                     }
 631                 }
 632                 if ($cyclic) {
 633                     // We can not do much with cyclic references here, let's use the old plugin.
 634                     $name = $oldname;
 635                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 636
 637                 } else if (empty($name)) {
 638                     // Developer requested removal of the plugin.
 639                     continue;
 640
 641                 } else if (!isset($this->jqueryplugins[$name])) {
 642                     debugging("Unknown jQuery override plugin '$name' detected");
 643                     $name = $oldname;
 644
 645                 } else if (isset($included[$name])) {
 646                     // The plugin was already included, easy.
 647                     continue;
 648                 }
 649             }
 650
 651             $plugin = $this->jqueryplugins[$name];
 652             $urls = array_merge($urls, $plugin->urls);
 653             $included[$name] = true;
 654         }
 655
 656         $output = '';
 657         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 658         foreach ($urls as $url) {
 659             if (preg_match('/\.js$/', $url)) {
 660                 $output .= html_writer::script('', $url);
 661             } else if (preg_match('/\.css$/', $url)) {
 662                 $attributes['href'] = $url;
 663                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 664             }
 665         }
 666
 667         return $output;
 668     }
 669
 670     /**
 671      * Returns the actual url through which a script is served.
 672      *
 673      * @param moodle_url|string $url full moodle url, or shortened path to script
 674      * @return moodle_url
 675      */
 676     protected function js_fix_url($url) {
 677         global $CFG;
 678
 679         if ($url instanceof moodle_url) {
 680             return $url;
 681         } else if (strpos($url, '/') === 0) {
 682             // Fix the admin links if needed.
 683             if ($CFG->admin !== 'admin') {
 684                 if (strpos($url, "/admin/") === 0) {
 685                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 686                 }
 687             }
 688             if (debugging()) {
 689                 // Check file existence only when in debug mode.
 690                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 691                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 692                 }
 693             }
 694             if (substr($url, -3) === '.js') {
 695                 $jsrev = $this->get_jsrev();
 696                 if (empty($CFG->slasharguments)) {
 697                     return new moodle_url($CFG->httpswwwroot.'/lib/javascript.php', array('rev'=>$jsrev, 'jsfile'=>$url));
 698                 } else {
 699                     $returnurl = new moodle_url($CFG->httpswwwroot.'/lib/javascript.php');
 700                     $returnurl->set_slashargument('/'.$jsrev.$url);
 701                     return $returnurl;
 702                 }
 703             } else {
 704                 return new moodle_url($CFG->httpswwwroot.$url);
 705             }
 706         } else {
 707             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 708         }
 709     }
 710
 711     /**
 712      * Find out if JS module present and return details.
 713      *
 714      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 715      * @return array description of module or null if not found
 716      */
 717     protected function find_module($component) {
 718         global $CFG, $PAGE;
 719
 720         $module = null;
 721
 722         if (strpos($component, 'core_') === 0) {
 723             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 724             // so that we do nto have to repeat the definition of these modules over and over again.
 725             switch($component) {
 726                 case 'core_filepicker':
 727                     $module = array('name'     => 'core_filepicker',
 728                                     'fullpath' => '/repository/filepicker.js',
 729                                     'requires' => array('base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form', 'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin', 'escape', 'moodle-core_filepicker'),
 730                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 731                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 732                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 733                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 734                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 735                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 736                                                         array('referencesexist', 'repository'), array('select', 'repository')
 737                                                     ));
 738                     break;
 739                 case 'core_comment':
 740                     $module = array('name'     => 'core_comment',
 741                                     'fullpath' => '/comment/comment.js',
 742                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay'),
 743                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 744                                 );
 745                     break;
 746                 case 'core_role':
 747                     $module = array('name'     => 'core_role',
 748                                     'fullpath' => '/admin/roles/module.js',
 749                                     'requires' => array('node', 'cookie'));
 750                     break;
 751                 case 'core_completion':
 752                     $module = array('name'     => 'core_completion',
 753                                     'fullpath' => '/course/completion.js');
 754                     break;
 755                 case 'core_message':
 756                     $module = array('name'     => 'core_message',
 757                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 758                                     'fullpath' => '/message/module.js');
 759                     break;
 760                 case 'core_group':
 761                     $module = array('name'     => 'core_group',
 762                                     'fullpath' => '/group/module.js',
 763                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 764                     break;
 765                 case 'core_question_engine':
 766                     $module = array('name'     => 'core_question_engine',
 767                                     'fullpath' => '/question/qengine.js',
 768                                     'requires' => array('node', 'event'));
 769                     break;
 770                 case 'core_rating':
 771                     $module = array('name'     => 'core_rating',
 772                                     'fullpath' => '/rating/module.js',
 773                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 774                     break;
 775                 case 'core_dndupload':
 776                     $module = array('name'     => 'core_dndupload',
 777                                     'fullpath' => '/lib/form/dndupload.js',
 778                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 779                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 780                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesforfile', 'moodle'),
 781                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 782                                                     ));
 783                     break;
 784             }
 785
 786         } else {
 787             if ($dir = core_component::get_component_directory($component)) {
 788                 if (file_exists("$dir/module.js")) {
 789                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 790                         $dir = substr($dir, strlen($CFG->dirroot));
 791                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 792                     }
 793                 }
 794             }
 795         }
 796
 797         return $module;
 798     }
 799
 800     /**
 801      * Append YUI3 module to default YUI3 JS loader.
 802      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 803      *
 804      * @param string|array $module name of module (details are autodetected), or full module specification as array
 805      * @return void
 806      */
 807     public function js_module($module) {
 808         global $CFG;
 809
 810         if (empty($module)) {
 811             throw new coding_exception('Missing YUI3 module name or full description.');
 812         }
 813
 814         if (is_string($module)) {
 815             $module = $this->find_module($module);
 816         }
 817
 818         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 819             throw new coding_exception('Missing YUI3 module details.');
 820         }
 821
 822         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 823         // Add all needed strings.
 824         if (!empty($module['strings'])) {
 825             foreach ($module['strings'] as $string) {
 826                 $identifier = $string[0];
 827                 $component = isset($string[1]) ? $string[1] : 'moodle';
 828                 $a = isset($string[2]) ? $string[2] : null;
 829                 $this->string_for_js($identifier, $component, $a);
 830             }
 831         }
 832         unset($module['strings']);
 833
 834         // Process module requirements and attempt to load each. This allows
 835         // moodle modules to require each other.
 836         if (!empty($module['requires'])){
 837             foreach ($module['requires'] as $requirement) {
 838                 $rmodule = $this->find_module($requirement);
 839                 if (is_array($rmodule)) {
 840                     $this->js_module($rmodule);
 841                 }
 842             }
 843         }
 844
 845         if ($this->headdone) {
 846             $this->extramodules[$module['name']] = $module;
 847         } else {
 848             $this->YUI_config->add_module_config($module['name'], $module);
 849         }
 850     }
 851
 852     /**
 853      * Returns true if the module has already been loaded.
 854      *
 855      * @param string|array $module
 856      * @return bool True if the module has already been loaded
 857      */
 858     protected function js_module_loaded($module) {
 859         if (is_string($module)) {
 860             $modulename = $module;
 861         } else {
 862             $modulename = $module['name'];
 863         }
 864         return array_key_exists($modulename, $this->YUI_config->modules) ||
 865                array_key_exists($modulename, $this->extramodules);
 866     }
 867
 868     /**
 869      * Ensure that the specified CSS file is linked to from this page.
 870      *
 871      * Because stylesheet links must go in the <head> part of the HTML, you must call
 872      * this function before {@link get_head_code()} is called. That normally means before
 873      * the call to print_header. If you call it when it is too late, an exception
 874      * will be thrown.
 875      *
 876      * Even if a particular style sheet is requested more than once, it will only
 877      * be linked to once.
 878      *
 879      * Please note use of this feature is strongly discouraged,
 880      * it is suitable only for places where CSS is submitted directly by teachers.
 881      * (Students must not be allowed to submit any external CSS because it may
 882      * contain embedded javascript!). Example of correct use is mod/data.
 883      *
 884      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 885      *   For example:
 886      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 887      */
 888     public function css($stylesheet) {
 889         global $CFG;
 890
 891         if ($this->headdone) {
 892             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 893         }
 894
 895         if ($stylesheet instanceof moodle_url) {
 896             // ok
 897         } else if (strpos($stylesheet, '/') === 0) {
 898             $stylesheet = new moodle_url($CFG->httpswwwroot.$stylesheet);
 899         } else {
 900             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 901         }
 902
 903         $this->cssurls[$stylesheet->out()] = $stylesheet;
 904     }
 905
 906     /**
 907      * Add theme stylesheet to page - do not use from plugin code,
 908      * this should be called only from the core renderer!
 909      *
 910      * @param moodle_url $stylesheet
 911      * @return void
 912      */
 913     public function css_theme(moodle_url $stylesheet) {
 914         $this->cssthemeurls[] = $stylesheet;
 915     }
 916
 917     /**
 918      * Ensure that a skip link to a given target is printed at the top of the <body>.
 919      *
 920      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 921      * will be thrown). That normally means you must call this before the call to print_header.
 922      *
 923      * If you ask for a particular skip link to be printed, it is then your responsibility
 924      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 925      * page, so that the skip link goes somewhere.
 926      *
 927      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 928      *
 929      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 930      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 931      */
 932     public function skip_link_to($target, $linktext) {
 933         if ($this->topofbodydone) {
 934             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 935             return;
 936         }
 937         $this->skiplinks[$target] = $linktext;
 938     }
 939
 940     /**
 941      * !!!DEPRECATED!!! please use js_init_call() if possible
 942      * Ensure that the specified JavaScript function is called from an inline script
 943      * somewhere on this page.
 944      *
 945      * By default the call will be put in a script tag at the
 946      * end of the page after initialising Y instance, since this gives best page-load
 947      * performance and allows you to use YUI3 library.
 948      *
 949      * If you request that a particular function is called several times, then
 950      * that is what will happen (unlike linking to a CSS or JS file, where only
 951      * one link will be output).
 952      *
 953      * The main benefit of the method is the automatic encoding of all function parameters.
 954      *
 955      * @deprecated
 956      *
 957      * @param string $function the name of the JavaScritp function to call. Can
 958      *      be a compound name like 'Y.Event.purgeElement'. Can also be
 959      *      used to create and object by using a 'function name' like 'new user_selector'.
 960      * @param array $arguments and array of arguments to be passed to the function.
 961      *      When generating the function call, this will be escaped using json_encode,
 962      *      so passing objects and arrays should work.
 963      * @param bool $ondomready If tru the function is only called when the dom is
 964      *      ready for manipulation.
 965      * @param int $delay The delay before the function is called.
 966      */
 967     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
 968         $where = $ondomready ? 'ondomready' : 'normal';
 969         $this->jscalls[$where][] = array($function, $arguments, $delay);
 970     }
 971
 972     /**
 973      * This function appends a block of code to the AMD specific javascript block executed
 974      * in the page footer, just after loading the requirejs library.
 975      *
 976      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
 977      *
 978      * @param string $code The JS code to append.
 979      */
 980     public function js_amd_inline($code) {
 981         $this->amdjscode[] = $code;
 982     }
 983
 984     /**
 985      * This function creates a minimal JS script that requires and calls a single function from an AMD module with arguments.
 986      * If it is called multiple times, it will be executed multiple times.
 987      *
 988      * @param string $fullmodule The format for module names is <component name>/<module name>.
 989      * @param string $func The function from the module to call
 990      * @param array $params The params to pass to the function. They will be json encoded, so no nasty classes/types please.
 991      */
 992     public function js_call_amd($fullmodule, $func, $params = array()) {
 993         global $CFG;
 994
 995         list($component, $module) = explode('/', $fullmodule, 2);
 996
 997         $component = clean_param($component, PARAM_COMPONENT);
 998         $module = clean_param($module, PARAM_ALPHANUMEXT);
 999         $func = clean_param($func, PARAM_ALPHANUMEXT);
1000
1001         $jsonparams = array();
1002         foreach ($params as $param) {
1003             $jsonparams[] = json_encode($param);
1004         }
1005         $strparams = implode(', ', $jsonparams);
1006         if ($CFG->debugdeveloper) {
1007             $toomanyparamslimit = 1024;
1008             if (strlen($strparams) > $toomanyparamslimit) {
1009                 debugging('Too many params passed to js_call_amd("' . $fullmodule . '", "' . $func . '")', DEBUG_DEVELOPER);
1010             }
1011         }
1012
1013         $js = 'require(["' . $component . '/' . $module . '"], function(amd) { amd.' . $func . '(' . $strparams . '); });';
1014
1015         $this->js_amd_inline($js);
1016     }
1017
1018     /**
1019      * Creates a JavaScript function call that requires one or more modules to be loaded.
1020      *
1021      * This function can be used to include all of the standard YUI module types within JavaScript:
1022      *     - YUI3 modules    [node, event, io]
1023      *     - YUI2 modules    [yui2-*]
1024      *     - Moodle modules  [moodle-*]
1025      *     - Gallery modules [gallery-*]
1026      *
1027      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1028      * @see js_call_amd()
1029      *
1030      * @param array|string $modules One or more modules
1031      * @param string $function The function to call once modules have been loaded
1032      * @param array $arguments An array of arguments to pass to the function
1033      * @param string $galleryversion Deprecated: The gallery version to use
1034      * @param bool $ondomready
1035      */
1036     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1037         if (!is_array($modules)) {
1038             $modules = array($modules);
1039         }
1040
1041         if ($galleryversion != null) {
1042             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1043         }
1044
1045         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1046         if ($ondomready) {
1047             $jscode = "Y.on('domready', function() { $jscode });";
1048         }
1049         $this->jsinitcode[] = $jscode;
1050     }
1051
1052     /**
1053      * Ensure that the specified JavaScript function is called from an inline script
1054      * from page footer.
1055      *
1056      * @param string $function the name of the JavaScritp function to with init code,
1057      *      usually something like 'M.mod_mymodule.init'
1058      * @param array $extraarguments and array of arguments to be passed to the function.
1059      *      The first argument is always the YUI3 Y instance with all required dependencies
1060      *      already loaded.
1061      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1062      * @param array $module JS module specification array
1063      */
1064     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1065         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1066         if (!$module) {
1067             // Detect module automatically.
1068             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1069                 $module = $this->find_module($matches[1]);
1070             }
1071         }
1072
1073         $this->js_init_code($jscode, $ondomready, $module);
1074     }
1075
1076     /**
1077      * Add short static javascript code fragment to page footer.
1078      * This is intended primarily for loading of js modules and initialising page layout.
1079      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1080      * may override it.
1081      *
1082      * @param string $jscode
1083      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1084      * @param array $module JS module specification array
1085      */
1086     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1087         $jscode = trim($jscode, " ;\n"). ';';
1088
1089         $uniqid = html_writer::random_id();
1090         $startjs = " M.util.js_pending('" . $uniqid . "');";
1091         $endjs = " M.util.js_complete('" . $uniqid . "');";
1092
1093         if ($module) {
1094             $this->js_module($module);
1095             $modulename = $module['name'];
1096             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1097         }
1098
1099         if ($ondomready) {
1100             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1101         }
1102
1103         $this->jsinitcode[] = $jscode;
1104     }
1105
1106     /**
1107      * Make a language string available to JavaScript.
1108      *
1109      * All the strings will be available in a M.str object in the global namespace.
1110      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1111      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1112      * equivalent in the current language.
1113      *
1114      * The arguments to this function are just like the arguments to get_string
1115      * except that $component is not optional, and there are some aspects to consider
1116      * when the string contains {$a} placeholder.
1117      *
1118      * If the string does not contain any {$a} placeholder, you can simply use
1119      * M.str.component.identifier to obtain it. If you prefer, you can call
1120      * M.util.get_string(identifier, component) to get the same result.
1121      *
1122      * If you need to use {$a} placeholders, there are two options. Either the
1123      * placeholder should be substituted in PHP on server side or it should
1124      * be substituted in Javascript at client side.
1125      *
1126      * To substitute the placeholder at server side, just provide the required
1127      * value for the placeholder when you require the string. Because each string
1128      * is only stored once in the JavaScript (based on $identifier and $module)
1129      * you cannot get the same string with two different values of $a. If you try,
1130      * an exception will be thrown. Once the placeholder is substituted, you can
1131      * use M.str or M.util.get_string() as shown above:
1132      *
1133      *     // Require the string in PHP and replace the placeholder.
1134      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1135      *     // Use the result of the substitution in Javascript.
1136      *     alert(M.str.moodle.fullnamedisplay);
1137      *
1138      * To substitute the placeholder at client side, use M.util.get_string()
1139      * function. It implements the same logic as {@link get_string()}:
1140      *
1141      *     // Require the string in PHP but keep {$a} as it is.
1142      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1143      *     // Provide the values on the fly in Javascript.
1144      *     user = { firstname : 'Harry', lastname : 'Potter' }
1145      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1146      *
1147      * If you do need the same string expanded with different $a values in PHP
1148      * on server side, then the solution is to put them in your own data structure
1149      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1150      *
1151      * @param string $identifier the desired string.
1152      * @param string $component the language file to look in.
1153      * @param mixed $a any extra data to add into the string (optional).
1154      */
1155     public function string_for_js($identifier, $component, $a = null) {
1156         if (!$component) {
1157             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1158         }
1159         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1160             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1161                     "from lang file '$component' with different \$a parameter?");
1162         }
1163         if (!isset($this->stringsforjs[$component][$identifier])) {
1164             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1165             $this->stringsforjs_as[$component][$identifier] = $a;
1166         }
1167     }
1168
1169     /**
1170      * Make an array of language strings available for JS.
1171      *
1172      * This function calls the above function {@link string_for_js()} for each requested
1173      * string in the $identifiers array that is passed to the argument for a single module
1174      * passed in $module.
1175      *
1176      * <code>
1177      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1178      *
1179      * // The above is identical to calling:
1180      *
1181      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1182      * $PAGE->requires->string_for_js('two', 'mymod');
1183      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1184      * </code>
1185      *
1186      * @param array $identifiers An array of desired strings
1187      * @param string $component The module to load for
1188      * @param mixed $a This can either be a single variable that gets passed as extra
1189      *         information for every string or it can be an array of mixed data where the
1190      *         key for the data matches that of the identifier it is meant for.
1191      *
1192      */
1193     public function strings_for_js($identifiers, $component, $a = null) {
1194         foreach ($identifiers as $key => $identifier) {
1195             if (is_array($a) && array_key_exists($key, $a)) {
1196                 $extra = $a[$key];
1197             } else {
1198                 $extra = $a;
1199             }
1200             $this->string_for_js($identifier, $component, $extra);
1201         }
1202     }
1203
1204     /**
1205      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1206      *
1207      * Make some data from PHP available to JavaScript code.
1208      *
1209      * For example, if you call
1210      * <pre>
1211      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1212      * </pre>
1213      * then in JavsScript mydata.name will be 'Moodle'.
1214      *
1215      * @deprecated
1216      * @param string $variable the the name of the JavaScript variable to assign the data to.
1217      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1218      *      should be considered an experimental feature.
1219      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1220      *      so passing objects and arrays should work.
1221      * @param bool $inhead initialise in head
1222      * @return void
1223      */
1224     public function data_for_js($variable, $data, $inhead=false) {
1225         $where = $inhead ? 'head' : 'footer';
1226         $this->jsinitvariables[$where][] = array($variable, $data);
1227     }
1228
1229     /**
1230      * Creates a YUI event handler.
1231      *
1232      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1233      * @param string $event A valid DOM event (click, mousedown, change etc.)
1234      * @param string $function The name of the function to call
1235      * @param array  $arguments An optional array of argument parameters to pass to the function
1236      */
1237     public function event_handler($selector, $event, $function, array $arguments = null) {
1238         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1239     }
1240
1241     /**
1242      * Returns code needed for registering of event handlers.
1243      * @return string JS code
1244      */
1245     protected function get_event_handler_code() {
1246         $output = '';
1247         foreach ($this->eventhandlers as $h) {
1248             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1249         }
1250         return $output;
1251     }
1252
1253     /**
1254      * Get the inline JavaScript code that need to appear in a particular place.
1255      * @param bool $ondomready
1256      * @return string
1257      */
1258     protected function get_javascript_code($ondomready) {
1259         $where = $ondomready ? 'ondomready' : 'normal';
1260         $output = '';
1261         if ($this->jscalls[$where]) {
1262             foreach ($this->jscalls[$where] as $data) {
1263                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1264             }
1265             if (!empty($ondomready)) {
1266                 $output = "    Y.on('domready', function() {\n$output\n});";
1267             }
1268         }
1269         return $output;
1270     }
1271
1272     /**
1273      * Returns js code to be executed when Y is available.
1274      * @return string
1275      */
1276     protected function get_javascript_init_code() {
1277         if (count($this->jsinitcode)) {
1278             return implode("\n", $this->jsinitcode) . "\n";
1279         }
1280         return '';
1281     }
1282
1283     /**
1284      * Returns js code to load amd module loader, then insert inline script tags
1285      * that contain require() calls using RequireJS.
1286      * @return string
1287      */
1288     protected function get_amd_footercode() {
1289         global $CFG;
1290         $output = '';
1291         $jsrev = $this->get_jsrev();
1292
1293         $jsloader = new moodle_url($CFG->httpswwwroot . '/lib/javascript.php');
1294         $jsloader->set_slashargument('/' . $jsrev . '/');
1295         $requirejsloader = new moodle_url($CFG->httpswwwroot . '/lib/requirejs.php');
1296         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1297
1298         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1299
1300         // No extension required unless slash args is disabled.
1301         $jsextension = '.js';
1302         if (!empty($CFG->slasharguments)) {
1303             $jsextension = '';
1304         }
1305
1306         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1307         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1308         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1309
1310         $output .= html_writer::script($requirejsconfig);
1311         if ($CFG->debugdeveloper) {
1312             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1313         } else {
1314             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1315         }
1316
1317         // First include must be to a module with no dependencies, this prevents multiple requests.
1318         $prefix = "require(['core/first'], function() {\n";
1319         $suffix = "\n});";
1320         $output .= html_writer::script($prefix . implode(";\n", $this->amdjscode) . $suffix);
1321         return $output;
1322     }
1323
1324     /**
1325      * Returns basic YUI3 JS loading code.
1326      * YUI3 is using autoloading of both CSS and JS code.
1327      *
1328      * Major benefit of this compared to standard js/csss loader is much improved
1329      * caching, better browser cache utilisation, much fewer http requests.
1330      *
1331      * @param moodle_page $page
1332      * @return string
1333      */
1334     protected function get_yui3lib_headcode($page) {
1335         global $CFG;
1336
1337         $code = '';
1338
1339         $jsrev = $this->get_jsrev();
1340
1341         $yuiformat = '-min';
1342         if ($this->yui3loader->filter === 'RAW') {
1343             $yuiformat = '';
1344         }
1345
1346         $format = '-min';
1347         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1348             $format = '-debug';
1349         }
1350
1351         $rollupversion = $CFG->yui3version;
1352         if (!empty($CFG->yuipatchlevel)) {
1353             $rollupversion .= '_' . $CFG->yuipatchlevel;
1354         }
1355
1356         $baserollups = array(
1357             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1358             'rollup/' . $jsrev . "/mcore{$format}.js",
1359         );
1360
1361         if ($this->yui3loader->combine) {
1362             if (!empty($page->theme->yuicssmodules)) {
1363                 $modules = array();
1364                 foreach ($page->theme->yuicssmodules as $module) {
1365                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1366                 }
1367                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1368             }
1369             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1370             $code .= '<script type="text/javascript" src="'.$this->yui3loader->local_comboBase
1371                     . implode('&amp;', $baserollups) . '"></script>';
1372
1373         } else {
1374             if (!empty($page->theme->yuicssmodules)) {
1375                 foreach ($page->theme->yuicssmodules as $module) {
1376                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1377                 }
1378             }
1379             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1380             foreach ($baserollups as $rollup) {
1381                 $code .= '<script type="text/javascript" src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1382             }
1383         }
1384
1385         if ($this->yui3loader->filter === 'RAW') {
1386             $code = str_replace('-min.css', '.css', $code);
1387         } else if ($this->yui3loader->filter === 'DEBUG') {
1388             $code = str_replace('-min.css', '.css', $code);
1389         }
1390         return $code;
1391     }
1392
1393     /**
1394      * Returns html tags needed for inclusion of theme CSS.
1395      *
1396      * @return string
1397      */
1398     protected function get_css_code() {
1399         // First of all the theme CSS, then any custom CSS
1400         // Please note custom CSS is strongly discouraged,
1401         // because it can not be overridden by themes!
1402         // It is suitable only for things like mod/data which accepts CSS from teachers.
1403         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1404
1405         // This line of code may look funny but it is currently required in order
1406         // to avoid MASSIVE display issues in Internet Explorer.
1407         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1408         // ignored whenever another resource is added until such time as a redraw
1409         // is forced, usually by moving the mouse over the affected element.
1410         $code = html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1411
1412         $urls = $this->cssthemeurls + $this->cssurls;
1413         foreach ($urls as $url) {
1414             $attributes['href'] = $url;
1415             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1416             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1417             unset($attributes['id']);
1418         }
1419
1420         return $code;
1421     }
1422
1423     /**
1424      * Adds extra modules specified after printing of page header.
1425      *
1426      * @return string
1427      */
1428     protected function get_extra_modules_code() {
1429         if (empty($this->extramodules)) {
1430             return '';
1431         }
1432         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1433     }
1434
1435     /**
1436      * Generate any HTML that needs to go inside the <head> tag.
1437      *
1438      * Normally, this method is called automatically by the code that prints the
1439      * <head> tag. You should not normally need to call it in your own code.
1440      *
1441      * @param moodle_page $page
1442      * @param core_renderer $renderer
1443      * @return string the HTML code to to inside the <head> tag.
1444      */
1445     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1446         global $CFG;
1447
1448         // Note: the $page and $output are not stored here because it would
1449         // create circular references in memory which prevents garbage collection.
1450         $this->init_requirements_data($page, $renderer);
1451
1452         $output = '';
1453
1454         // Set up the M namespace.
1455         $js = "var M = {}; M.yui = {};\n";
1456
1457         // Capture the time now ASAP during page load. This minimises the lag when
1458         // we try to relate times on the server to times in the browser.
1459         // An example of where this is used is the quiz countdown timer.
1460         $js .= "M.pageloadstarttime = new Date();\n";
1461
1462         // Add a subset of Moodle configuration to the M namespace.
1463         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1464
1465         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1466         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1467         //       this needs to be done before including any other script.
1468         $js .= $this->YUI_config->get_config_functions();
1469         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1470         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1471         $js = $this->YUI_config->update_header_js($js);
1472
1473         $output .= html_writer::script($js);
1474
1475         // YUI3 JS and CSS need to be loaded in the header but after the YUI_config has been created.
1476         // They should be cached well by the browser.
1477         $output .= $this->get_yui3lib_headcode($page);
1478
1479         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1480         $output .= $this->get_jquery_headcode();
1481
1482         // Now theme CSS + custom CSS in this specific order.
1483         $output .= $this->get_css_code();
1484
1485         // Link our main JS file, all core stuff should be there.
1486         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1487
1488         // Add variables.
1489         if ($this->jsinitvariables['head']) {
1490             $js = '';
1491             foreach ($this->jsinitvariables['head'] as $data) {
1492                 list($var, $value) = $data;
1493                 $js .= js_writer::set_variable($var, $value, true);
1494             }
1495             $output .= html_writer::script($js);
1496         }
1497
1498         // All the other linked things from HEAD - there should be as few as possible.
1499         if ($this->jsincludes['head']) {
1500             foreach ($this->jsincludes['head'] as $url) {
1501                 $output .= html_writer::script('', $url);
1502             }
1503         }
1504
1505         // Mark head sending done, it is not possible to anything there.
1506         $this->headdone = true;
1507
1508         return $output;
1509     }
1510
1511     /**
1512      * Generate any HTML that needs to go at the start of the <body> tag.
1513      *
1514      * Normally, this method is called automatically by the code that prints the
1515      * <head> tag. You should not normally need to call it in your own code.
1516      *
1517      * @return string the HTML code to go at the start of the <body> tag.
1518      */
1519     public function get_top_of_body_code() {
1520         // First the skip links.
1521         $links = '';
1522         $attributes = array('class'=>'skip');
1523         foreach ($this->skiplinks as $url => $text) {
1524             $attributes['href'] = '#' . $url;
1525             $links .= html_writer::tag('a', $text, $attributes);
1526         }
1527         $output = html_writer::tag('div', $links, array('class'=>'skiplinks')) . "\n";
1528
1529         // Then the clever trick for hiding of things not needed when JS works.
1530         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1531         $this->topofbodydone = true;
1532         return $output;
1533     }
1534
1535     /**
1536      * Generate any HTML that needs to go at the end of the page.
1537      *
1538      * Normally, this method is called automatically by the code that prints the
1539      * page footer. You should not normally need to call it in your own code.
1540      *
1541      * @return string the HTML code to to at the end of the page.
1542      */
1543     public function get_end_code() {
1544         global $CFG;
1545         $output = '';
1546
1547         // Set the log level for the JS logging.
1548         $logconfig = new stdClass();
1549         $logconfig->level = 'warn';
1550         if ($CFG->debugdeveloper) {
1551             $logconfig->level = 'trace';
1552         }
1553         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1554
1555         // Call amd init functions.
1556         $output .= $this->get_amd_footercode();
1557
1558         // Add other requested modules.
1559         $output .= $this->get_extra_modules_code();
1560
1561         $this->js_init_code('M.util.js_complete("init");', true);
1562
1563         // All the other linked scripts - there should be as few as possible.
1564         if ($this->jsincludes['footer']) {
1565             foreach ($this->jsincludes['footer'] as $url) {
1566                 $output .= html_writer::script('', $url);
1567             }
1568         }
1569
1570         // Add all needed strings.
1571         // First add core strings required for some dialogues.
1572         $this->strings_for_js(array(
1573             'confirm',
1574             'yes',
1575             'no',
1576             'areyousure',
1577             'closebuttontitle',
1578             'unknownerror',
1579         ), 'moodle');
1580         if (!empty($this->stringsforjs)) {
1581             $strings = array();
1582             foreach ($this->stringsforjs as $component=>$v) {
1583                 foreach($v as $indentifier => $langstring) {
1584                     $strings[$component][$indentifier] = $langstring->out();
1585                 }
1586             }
1587             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1588         }
1589
1590         // Add variables.
1591         if ($this->jsinitvariables['footer']) {
1592             $js = '';
1593             foreach ($this->jsinitvariables['footer'] as $data) {
1594                 list($var, $value) = $data;
1595                 $js .= js_writer::set_variable($var, $value, true);
1596             }
1597             $output .= html_writer::script($js);
1598         }
1599
1600         $inyuijs = $this->get_javascript_code(false);
1601         $ondomreadyjs = $this->get_javascript_code(true);
1602         $jsinit = $this->get_javascript_init_code();
1603         $handlersjs = $this->get_event_handler_code();
1604
1605         // There is no global Y, make sure it is available in your scope.
1606         $js = "YUI().use('node', function(Y) {\n{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}\n});";
1607
1608         $output .= html_writer::script($js);
1609
1610         return $output;
1611     }
1612
1613     /**
1614      * Have we already output the code in the <head> tag?
1615      *
1616      * @return bool
1617      */
1618     public function is_head_done() {
1619         return $this->headdone;
1620     }
1621
1622     /**
1623      * Have we already output the code at the start of the <body> tag?
1624      *
1625      * @return bool
1626      */
1627     public function is_top_of_body_done() {
1628         return $this->topofbodydone;
1629     }
1630
1631     /**
1632      * Should we generate a bit of content HTML that is only required once  on
1633      * this page (e.g. the contents of the modchooser), now? Basically, we call
1634      * {@link has_one_time_item_been_created()}, and if the thing has not already
1635      * been output, we return true to tell the caller to generate it, and also
1636      * call {@link set_one_time_item_created()} to record the fact that it is
1637      * about to be generated.
1638      *
1639      * That is, a typical usage pattern (in a renderer method) is:
1640      * <pre>
1641      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1642      *     return '';
1643      * }
1644      * // Else generate it.
1645      * </pre>
1646      *
1647      * @param string $thing identifier for the bit of content. Should be of the form
1648      *      frankenstyle_things, e.g. core_course_modchooser.
1649      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1650      */
1651     public function should_create_one_time_item_now($thing) {
1652         if ($this->has_one_time_item_been_created($thing)) {
1653             return false;
1654         }
1655
1656         $this->set_one_time_item_created($thing);
1657         return true;
1658     }
1659
1660     /**
1661      * Has a particular bit of HTML that is only required once  on this page
1662      * (e.g. the contents of the modchooser) already been generated?
1663      *
1664      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1665      * method rather than calling this method directly.
1666      *
1667      * @param string $thing identifier for the bit of content. Should be of the form
1668      *      frankenstyle_things, e.g. core_course_modchooser.
1669      * @return bool whether that bit of output has been created.
1670      */
1671     public function has_one_time_item_been_created($thing) {
1672         return isset($this->onetimeitemsoutput[$thing]);
1673     }
1674
1675     /**
1676      * Indicate that a particular bit of HTML that is only required once on this
1677      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1678      *
1679      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1680      * method rather than calling this method directly.
1681      *
1682      * @param string $thing identifier for the bit of content. Should be of the form
1683      *      frankenstyle_things, e.g. core_course_modchooser.
1684      */
1685     public function set_one_time_item_created($thing) {
1686         if ($this->has_one_time_item_been_created($thing)) {
1687             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1688                     'once per page, but it seems to be being output again.');
1689         }
1690         return $this->onetimeitemsoutput[$thing] = true;
1691     }
1692 }
1693
1694 /**
1695  * This class represents the YUI configuration.
1696  *
1697  * @copyright 2013 Andrew Nicols
1698  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1699  * @since Moodle 2.5
1700  * @package core
1701  * @category output
1702  */
1703 class YUI_config {
1704     /**
1705      * These settings must be public so that when the object is converted to json they are exposed.
1706      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1707      *
1708      * The settings are described and documented in the YUI API at:
1709      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1710      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1711      */
1712     public $debug = false;
1713     public $base;
1714     public $comboBase;
1715     public $combine;
1716     public $filter = null;
1717     public $insertBefore = 'firstthemesheet';
1718     public $groups = array();
1719     public $modules = array();
1720
1721     /**
1722      * @var array List of functions used by the YUI Loader group pattern recognition.
1723      */
1724     protected $jsconfigfunctions = array();
1725
1726     /**
1727      * Create a new group within the YUI_config system.
1728      *
1729      * @param String $name The name of the group. This must be unique and
1730      * not previously used.
1731      * @param Array $config The configuration for this group.
1732      * @return void
1733      */
1734     public function add_group($name, $config) {
1735         if (isset($this->groups[$name])) {
1736             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1737         }
1738         $this->groups[$name] = $config;
1739     }
1740
1741     /**
1742      * Update an existing group configuration
1743      *
1744      * Note, any existing configuration for that group will be wiped out.
1745      * This includes module configuration.
1746      *
1747      * @param String $name The name of the group. This must be unique and
1748      * not previously used.
1749      * @param Array $config The configuration for this group.
1750      * @return void
1751      */
1752     public function update_group($name, $config) {
1753         if (!isset($this->groups[$name])) {
1754             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.');
1755         }
1756         $this->groups[$name] = $config;
1757     }
1758
1759     /**
1760      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1761      *
1762      * Only the body of the function should be passed, and not the whole function wrapper.
1763      *
1764      * The JS function your write will be passed a single argument 'name' containing the
1765      * name of the module being loaded.
1766      *
1767      * @param $function String the body of the JavaScript function. This should be used i
1768      * @return String the name of the function to use in the group pattern configuration.
1769      */
1770     public function set_config_function($function) {
1771         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1772         if (isset($this->jsconfigfunctions[$configname])) {
1773             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1774         }
1775         $this->jsconfigfunctions[$configname] = $function;
1776         return '@' . $configname . '@';
1777     }
1778
1779     /**
1780      * Allow setting of the config function described in {@see set_config_function} from a file.
1781      * The contents of this file are then passed to set_config_function.
1782      *
1783      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1784      *
1785      * @param $file The path to the JavaScript function used for YUI configuration.
1786      * @return String the name of the function to use in the group pattern configuration.
1787      */
1788     public function set_config_source($file) {
1789         global $CFG;
1790         $cache = cache::make('core', 'yuimodules');
1791
1792         // Attempt to get the metadata from the cache.
1793         $keyname = 'configfn_' . $file;
1794         $fullpath = $CFG->dirroot . '/' . $file;
1795         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1796             $cache->delete($keyname);
1797             $configfn = file_get_contents($fullpath);
1798         } else {
1799             $configfn = $cache->get($keyname);
1800             if ($configfn === false) {
1801                 require_once($CFG->libdir . '/jslib.php');
1802                 $configfn = core_minify::js_files(array($fullpath));
1803                 $cache->set($keyname, $configfn);
1804             }
1805         }
1806         return $this->set_config_function($configfn);
1807     }
1808
1809     /**
1810      * Retrieve the list of JavaScript functions for YUI_config groups.
1811      *
1812      * @return String The complete set of config functions
1813      */
1814     public function get_config_functions() {
1815         $configfunctions = '';
1816         foreach ($this->jsconfigfunctions as $functionname => $function) {
1817             $configfunctions .= "var {$functionname} = function(me) {";
1818             $configfunctions .= $function;
1819             $configfunctions .= "};\n";
1820         }
1821         return $configfunctions;
1822     }
1823
1824     /**
1825      * Update the header JavaScript with any required modification for the YUI Loader.
1826      *
1827      * @param $js String The JavaScript to manipulate.
1828      * @return String the modified JS string.
1829      */
1830     public function update_header_js($js) {
1831         // Update the names of the the configFn variables.
1832         // The PHP json_encode function cannot handle literal names so we have to wrap
1833         // them in @ and then replace them with literals of the same function name.
1834         foreach ($this->jsconfigfunctions as $functionname => $function) {
1835             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1836         }
1837         return $js;
1838     }
1839
1840     /**
1841      * Add configuration for a specific module.
1842      *
1843      * @param String $name The name of the module to add configuration for.
1844      * @param Array $config The configuration for the specified module.
1845      * @param String $group The name of the group to add configuration for.
1846      * If not specified, then this module is added to the global
1847      * configuration.
1848      * @return void
1849      */
1850     public function add_module_config($name, $config, $group = null) {
1851         if ($group) {
1852             if (!isset($this->groups[$name])) {
1853                 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.');
1854             }
1855             if (!isset($this->groups[$group]['modules'])) {
1856                 $this->groups[$group]['modules'] = array();
1857             }
1858             $modules = &$this->groups[$group]['modules'];
1859         } else {
1860             $modules = &$this->modules;
1861         }
1862         $modules[$name] = $config;
1863     }
1864
1865     /**
1866      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
1867      *
1868      * If js caching is disabled, metadata will not be served causing YUI to calculate
1869      * module dependencies as each module is loaded.
1870      *
1871      * If metadata does not exist it will be created and stored in a MUC entry.
1872      *
1873      * @return void
1874      */
1875     public function add_moodle_metadata() {
1876         global $CFG;
1877         if (!isset($this->groups['moodle'])) {
1878             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.');
1879         }
1880
1881         if (!isset($this->groups['moodle']['modules'])) {
1882             $this->groups['moodle']['modules'] = array();
1883         }
1884
1885         $cache = cache::make('core', 'yuimodules');
1886         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1887             $metadata = array();
1888             $metadata = $this->get_moodle_metadata();
1889             $cache->delete('metadata');
1890         } else {
1891             // Attempt to get the metadata from the cache.
1892             if (!$metadata = $cache->get('metadata')) {
1893                 $metadata = $this->get_moodle_metadata();
1894                 $cache->set('metadata', $metadata);
1895             }
1896         }
1897
1898         // Merge with any metadata added specific to this page which was added manually.
1899         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
1900                 $metadata);
1901     }
1902
1903     /**
1904      * Determine the module metadata for all moodle YUI modules.
1905      *
1906      * This works through all modules capable of serving YUI modules, and attempts to get
1907      * metadata for each of those modules.
1908      *
1909      * @return Array of module metadata
1910      */
1911     private function get_moodle_metadata() {
1912         $moodlemodules = array();
1913         // Core isn't a plugin type or subsystem - handle it seperately.
1914         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
1915             $moodlemodules = array_merge($moodlemodules, $module);
1916         }
1917
1918         // Handle other core subsystems.
1919         $subsystems = core_component::get_core_subsystems();
1920         foreach ($subsystems as $subsystem => $path) {
1921             if (is_null($path)) {
1922                 continue;
1923             }
1924             if ($module = $this->get_moodle_path_metadata($path)) {
1925                 $moodlemodules = array_merge($moodlemodules, $module);
1926             }
1927         }
1928
1929         // And finally the plugins.
1930         $plugintypes = core_component::get_plugin_types();
1931         foreach ($plugintypes as $plugintype => $pathroot) {
1932             $pluginlist = core_component::get_plugin_list($plugintype);
1933             foreach ($pluginlist as $plugin => $path) {
1934                 if ($module = $this->get_moodle_path_metadata($path)) {
1935                     $moodlemodules = array_merge($moodlemodules, $module);
1936                 }
1937             }
1938         }
1939
1940         return $moodlemodules;
1941     }
1942
1943     /**
1944      * Helper function process and return the YUI metadata for all of the modules under the specified path.
1945      *
1946      * @param String $path the UNC path to the YUI src directory.
1947      * @return Array the complete array for frankenstyle directory.
1948      */
1949     private function get_moodle_path_metadata($path) {
1950         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
1951         $baseyui = $path . '/yui/src';
1952         $modules = array();
1953         if (is_dir($baseyui)) {
1954             $items = new DirectoryIterator($baseyui);
1955             foreach ($items as $item) {
1956                 if ($item->isDot() or !$item->isDir()) {
1957                     continue;
1958                 }
1959                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
1960                 if (!is_readable($metafile)) {
1961                     continue;
1962                 }
1963                 $metadata = file_get_contents($metafile);
1964                 $modules = array_merge($modules, (array) json_decode($metadata));
1965             }
1966         }
1967         return $modules;
1968     }
1969
1970     /**
1971      * Define YUI modules which we have been required to patch between releases.
1972      *
1973      * We must do this because we aggressively cache content on the browser, and we must also override use of the
1974      * external CDN which will serve the true authoritative copy of the code without our patches.
1975      *
1976      * @param String combobase The local combobase
1977      * @param String yuiversion The current YUI version
1978      * @param Int patchlevel The patch level we're working to for YUI
1979      * @param Array patchedmodules An array containing the names of the patched modules
1980      * @return void
1981      */
1982     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
1983         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
1984         $subversion = $yuiversion . '_' . $patchlevel;
1985
1986         if ($this->comboBase == $combobase) {
1987             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
1988             // loader. We just need to specify a different root which includes a slightly different YUI version number
1989             // to include our patchlevel.
1990             $patterns = array();
1991             $modules = array();
1992             foreach ($patchedmodules as $modulename) {
1993                 // We must define the pattern and module here so that the loader uses our group configuration instead of
1994                 // the standard module definition. We may lose some metadata provided by upstream but this will be
1995                 // loaded when the module is loaded anyway.
1996                 $patterns[$modulename] = array(
1997                     'group' => 'yui-patched',
1998                 );
1999                 $modules[$modulename] = array();
2000             }
2001
2002             // Actually add the patch group here.
2003             $this->add_group('yui-patched', array(
2004                 'combine' => true,
2005                 'root' => $subversion . '/',
2006                 'patterns' => $patterns,
2007                 'modules' => $modules,
2008             ));
2009
2010         } else {
2011             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2012             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2013             // local base in browser caches.
2014             $fullpathbase = $combobase . $subversion . '/';
2015             foreach ($patchedmodules as $modulename) {
2016                 $this->modules[$modulename] = array(
2017                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2018                 );
2019             }
2020         }
2021     }
2022 }
2023
2024 /**
2025  * Invalidate all server and client side JS caches.
2026  */
2027 function js_reset_all_caches() {
2028     global $CFG;
2029
2030     $next = time();
2031     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2032         // This resolves problems when reset is requested repeatedly within 1s,
2033         // the < 1h condition prevents accidental switching to future dates
2034         // because we might not recover from it.
2035         $next = $CFG->jsrev+1;
2036     }
2037
2038     set_config('jsrev', $next);
2039 }