lib/outputrequirementslib.php

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