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         // Set up some loader options.
 184         $this->yui3loader->local_base = $CFG->wwwroot . '/lib/yuilib/'. $CFG->yui3version . '/';
 185         $this->yui3loader->local_comboBase = $CFG->wwwroot . '/theme/yui_combo.php'.$sep;
 186
 187         $this->yui3loader->base = $this->yui3loader->local_base;
 188         $this->yui3loader->comboBase = $this->yui3loader->local_comboBase;
 189
 190         // Enable combo loader? This significantly helps with caching and performance!
 191         $this->yui3loader->combine = !empty($CFG->yuicomboloading);
 192
 193         $jsrev = $this->get_jsrev();
 194
 195         // Set up JS YUI loader helper object.
 196         $this->YUI_config->base         = $this->yui3loader->base;
 197         $this->YUI_config->comboBase    = $this->yui3loader->comboBase;
 198         $this->YUI_config->combine      = $this->yui3loader->combine;
 199
 200         // If we've had to patch any YUI modules between releases, we must override the YUI configuration to include them.
 201         // For important information on patching YUI modules, please see http://docs.moodle.org/dev/YUI/Patching.
 202         if (!empty($CFG->yuipatchedmodules) && !empty($CFG->yuipatchlevel)) {
 203             $this->YUI_config->define_patched_core_modules($this->yui3loader->local_comboBase,
 204                     $CFG->yui3version,
 205                     $CFG->yuipatchlevel,
 206                     $CFG->yuipatchedmodules);
 207         }
 208
 209         $configname = $this->YUI_config->set_config_source('lib/yui/config/yui2.js');
 210         $this->YUI_config->add_group('yui2', array(
 211             // Loader configuration for our 2in3.
 212             'base' => $CFG->wwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 213             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 214             'combine' => $this->yui3loader->combine,
 215             'ext' => false,
 216             'root' => '2in3/' . $CFG->yui2version .'/build/',
 217             'patterns' => array(
 218                 'yui2-' => array(
 219                     'group' => 'yui2',
 220                     'configFn' => $configname,
 221                 )
 222             )
 223         ));
 224         $configname = $this->YUI_config->set_config_source('lib/yui/config/moodle.js');
 225         $this->YUI_config->add_group('moodle', array(
 226             'name' => 'moodle',
 227             'base' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep . 'm/' . $jsrev . '/',
 228             'combine' => $this->yui3loader->combine,
 229             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 230             'ext' => false,
 231             'root' => 'm/'.$jsrev.'/', // Add the rev to the root path so that we can control caching.
 232             'patterns' => array(
 233                 'moodle-' => array(
 234                     'group' => 'moodle',
 235                     'configFn' => $configname,
 236                 )
 237             )
 238         ));
 239
 240         $this->YUI_config->add_group('gallery', array(
 241             'name' => 'gallery',
 242             'base' => $CFG->wwwroot . '/lib/yuilib/gallery/',
 243             'combine' => $this->yui3loader->combine,
 244             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep,
 245             'ext' => false,
 246             'root' => 'gallery/' . $jsrev . '/',
 247             'patterns' => array(
 248                 'gallery-' => array(
 249                     'group' => 'gallery',
 250                 )
 251             )
 252         ));
 253
 254         // Set some more loader options applying to groups too.
 255         if ($CFG->debugdeveloper) {
 256             // When debugging is enabled, we want to load the non-minified (RAW) versions of YUI library modules rather
 257             // than the DEBUG versions as these generally generate too much logging for our purposes.
 258             // However we do want the DEBUG versions of our Moodle-specific modules.
 259             // To debug a YUI-specific issue, change the yui3loader->filter value to DEBUG.
 260             $this->YUI_config->filter = 'RAW';
 261             $this->YUI_config->groups['moodle']['filter'] = 'DEBUG';
 262
 263             // We use the yui3loader->filter setting when writing the YUI3 seed scripts into the header.
 264             $this->yui3loader->filter = $this->YUI_config->filter;
 265             $this->YUI_config->debug = true;
 266         } else {
 267             $this->yui3loader->filter = null;
 268             $this->YUI_config->groups['moodle']['filter'] = null;
 269             $this->YUI_config->debug = false;
 270         }
 271
 272         // Include the YUI config log filters.
 273         if (!empty($CFG->yuilogexclude) && is_array($CFG->yuilogexclude)) {
 274             $this->YUI_config->logExclude = $CFG->yuilogexclude;
 275         }
 276         if (!empty($CFG->yuiloginclude) && is_array($CFG->yuiloginclude)) {
 277             $this->YUI_config->logInclude = $CFG->yuiloginclude;
 278         }
 279         if (!empty($CFG->yuiloglevel)) {
 280             $this->YUI_config->logLevel = $CFG->yuiloglevel;
 281         }
 282
 283         // Add the moodle group's module data.
 284         $this->YUI_config->add_moodle_metadata();
 285
 286         // Every page should include definition of following modules.
 287         $this->js_module($this->find_module('core_filepicker'));
 288         $this->js_module($this->find_module('core_comment'));
 289     }
 290
 291     /**
 292      * Return the safe config values that get set for javascript in "M.cfg".
 293      *
 294      * @since 2.9
 295      * @return array List of safe config values that are available to javascript.
 296      */
 297     public function get_config_for_javascript(moodle_page $page, renderer_base $renderer) {
 298         global $CFG;
 299
 300         if (empty($this->M_cfg)) {
 301
 302             $iconsystem = \core\output\icon_system::instance();
 303
 304             // It is possible that the $page->context is null, so we can't use $page->context->id.
 305             $contextid = null;
 306             $contextinstanceid = null;
 307             if (!is_null($page->context)) {
 308                 $contextid = $page->context->id;
 309                 $contextinstanceid = $page->context->instanceid;
 310                 $courseid = $page->course->id;
 311                 $coursecontext = context_course::instance($courseid);
 312             }
 313
 314             $this->M_cfg = array(
 315                 'wwwroot'               => $CFG->wwwroot,
 316                 'homeurl'               => $page->navigation->action,
 317                 'sesskey'               => sesskey(),
 318                 'sessiontimeout'        => $CFG->sessiontimeout,
 319                 'sessiontimeoutwarning' => $CFG->sessiontimeoutwarning,
 320                 'themerev'              => theme_get_revision(),
 321                 'slasharguments'        => (int)(!empty($CFG->slasharguments)),
 322                 'theme'                 => $page->theme->name,
 323                 'iconsystemmodule'      => $iconsystem->get_amd_name(),
 324                 'jsrev'                 => $this->get_jsrev(),
 325                 'admin'                 => $CFG->admin,
 326                 'svgicons'              => $page->theme->use_svg_icons(),
 327                 'usertimezone'          => usertimezone(),
 328                 'courseId'              => isset($courseid) ? (int) $courseid : 0,
 329                 'courseContextId'       => isset($coursecontext) ? $coursecontext->id : 0,
 330                 'contextid'             => $contextid,
 331                 'contextInstanceId'     => (int) $contextinstanceid,
 332                 'langrev'               => get_string_manager()->get_revision(),
 333                 'templaterev'           => $this->get_templaterev()
 334             );
 335             if ($CFG->debugdeveloper) {
 336                 $this->M_cfg['developerdebug'] = true;
 337             }
 338             if (defined('BEHAT_SITE_RUNNING')) {
 339                 $this->M_cfg['behatsiterunning'] = true;
 340             }
 341
 342         }
 343         return $this->M_cfg;
 344     }
 345
 346     /**
 347      * Initialise with the bits of JavaScript that every Moodle page should have.
 348      *
 349      * @param moodle_page $page
 350      * @param core_renderer $renderer
 351      */
 352     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 353         global $CFG;
 354
 355         // Init the js config.
 356         $this->get_config_for_javascript($page, $renderer);
 357
 358         // Accessibility stuff.
 359         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 360
 361         // Add strings used on many pages.
 362         $this->string_for_js('confirmation', 'admin');
 363         $this->string_for_js('cancel', 'moodle');
 364         $this->string_for_js('yes', 'moodle');
 365
 366         // Alter links in top frame to break out of frames.
 367         if ($page->pagelayout === 'frametop') {
 368             $this->js_init_call('M.util.init_frametop');
 369         }
 370
 371         // Include block drag/drop if editing is on
 372         if ($page->user_is_editing()) {
 373             $params = array(
 374                 'courseid' => $page->course->id,
 375                 'pagetype' => $page->pagetype,
 376                 'pagelayout' => $page->pagelayout,
 377                 'subpage' => $page->subpage,
 378                 'regions' => $page->blocks->get_regions(),
 379                 'contextid' => $page->context->id,
 380             );
 381             if (!empty($page->cm->id)) {
 382                 $params['cmid'] = $page->cm->id;
 383             }
 384             // Strings for drag and drop.
 385             $this->strings_for_js(array('movecontent',
 386                                         'tocontent',
 387                                         'emptydragdropregion'),
 388                                   'moodle');
 389             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 390         }
 391
 392         // Include the YUI CSS Modules.
 393         $page->requires->set_yuicssmodules($page->theme->yuicssmodules);
 394     }
 395
 396     /**
 397      * Determine the correct JS Revision to use for this load.
 398      *
 399      * @return int the jsrev to use.
 400      */
 401     public function get_jsrev() {
 402         global $CFG;
 403
 404         if (empty($CFG->cachejs)) {
 405             $jsrev = -1;
 406         } else if (empty($CFG->jsrev)) {
 407             $jsrev = 1;
 408         } else {
 409             $jsrev = $CFG->jsrev;
 410         }
 411
 412         return $jsrev;
 413     }
 414
 415     /**
 416      * Determine the correct Template revision to use for this load.
 417      *
 418      * @return int the templaterev to use.
 419      */
 420     protected function get_templaterev() {
 421         global $CFG;
 422
 423         if (empty($CFG->cachetemplates)) {
 424             $templaterev = -1;
 425         } else if (empty($CFG->templaterev)) {
 426             $templaterev = 1;
 427         } else {
 428             $templaterev = $CFG->templaterev;
 429         }
 430
 431         return $templaterev;
 432     }
 433
 434     /**
 435      * Ensure that the specified JavaScript file is linked to from this page.
 436      *
 437      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 438      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 439      *
 440      * By default the link is put at the end of the page, since this gives best page-load performance.
 441      *
 442      * Even if a particular script is requested more than once, it will only be linked
 443      * to once.
 444      *
 445      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 446      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 447      * @param bool $inhead initialise in head
 448      */
 449     public function js($url, $inhead = false) {
 450         if ($url == '/question/qengine.js') {
 451             debugging('The question/qengine.js has been deprecated. ' .
 452                 'Please use core_question/question_engine', DEBUG_DEVELOPER);
 453         }
 454         $url = $this->js_fix_url($url);
 455         $where = $inhead ? 'head' : 'footer';
 456         $this->jsincludes[$where][$url->out()] = $url;
 457     }
 458
 459     /**
 460      * Request inclusion of jQuery library in the page.
 461      *
 462      * NOTE: this should not be used in official Moodle distribution!
 463      *
 464      * {@see http://docs.moodle.org/dev/jQuery}
 465      */
 466     public function jquery() {
 467         $this->jquery_plugin('jquery');
 468     }
 469
 470     /**
 471      * Request inclusion of jQuery plugin.
 472      *
 473      * NOTE: this should not be used in official Moodle distribution!
 474      *
 475      * jQuery plugins are located in plugin/jquery/* subdirectory,
 476      * plugin/jquery/plugins.php lists all available plugins.
 477      *
 478      * Included core plugins:
 479      *   - jQuery UI
 480      *
 481      * Add-ons may include extra jQuery plugins in jquery/ directory,
 482      * plugins.php file defines the mapping between plugin names and
 483      * necessary page includes.
 484      *
 485      * Examples:
 486      * <code>
 487      *   // file: mod/xxx/view.php
 488      *   $PAGE->requires->jquery();
 489      *   $PAGE->requires->jquery_plugin('ui');
 490      *   $PAGE->requires->jquery_plugin('ui-css');
 491      * </code>
 492      *
 493      * <code>
 494      *   // file: theme/yyy/lib.php
 495      *   function theme_yyy_page_init(moodle_page $page) {
 496      *       $page->requires->jquery();
 497      *       $page->requires->jquery_plugin('ui');
 498      *       $page->requires->jquery_plugin('ui-css');
 499      *   }
 500      * </code>
 501      *
 502      * <code>
 503      *   // file: blocks/zzz/block_zzz.php
 504      *   public function get_required_javascript() {
 505      *       parent::get_required_javascript();
 506      *       $this->page->requires->jquery();
 507      *       $page->requires->jquery_plugin('ui');
 508      *       $page->requires->jquery_plugin('ui-css');
 509      *   }
 510      * </code>
 511      *
 512      * {@see http://docs.moodle.org/dev/jQuery}
 513      *
 514      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 515      * @param string $component name of the component
 516      * @return bool success
 517      */
 518     public function jquery_plugin($plugin, $component = 'core') {
 519         global $CFG;
 520
 521         if ($this->headdone) {
 522             debugging('Can not add jQuery plugins after starting page output!');
 523             return false;
 524         }
 525
 526         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css'))) {
 527             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 528             $component = 'core';
 529         } else if ($component !== 'core' and strpos($component, '_') === false) {
 530             // Let's normalise the legacy activity names, Frankenstyle rulez!
 531             $component = 'mod_' . $component;
 532         }
 533
 534         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 535             // Make sure the jQuery itself is always loaded first,
 536             // the order of all other plugins depends on order of $PAGE_>requires->.
 537             $this->jquery_plugin('jquery', 'core');
 538         }
 539
 540         if (isset($this->jqueryplugins[$plugin])) {
 541             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 542             return true;
 543         }
 544
 545         $componentdir = core_component::get_component_directory($component);
 546         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 547             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 548             return false;
 549         }
 550
 551         $plugins = array();
 552         require("$componentdir/jquery/plugins.php");
 553
 554         if (!isset($plugins[$plugin])) {
 555             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 556             return false;
 557         }
 558
 559         $this->jqueryplugins[$plugin] = new stdClass();
 560         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 561         $this->jqueryplugins[$plugin]->component = $component;
 562         $this->jqueryplugins[$plugin]->urls      = array();
 563
 564         foreach ($plugins[$plugin]['files'] as $file) {
 565             if ($CFG->debugdeveloper) {
 566                 if (!file_exists("$componentdir/jquery/$file")) {
 567                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 568                     continue;
 569                 }
 570                 $file = str_replace('.min.css', '.css', $file);
 571                 $file = str_replace('.min.js', '.js', $file);
 572             }
 573             if (!file_exists("$componentdir/jquery/$file")) {
 574                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 575                 continue;
 576             }
 577             if (!empty($CFG->slasharguments)) {
 578                 $url = new moodle_url("/theme/jquery.php");
 579                 $url->set_slashargument("/$component/$file");
 580
 581             } else {
 582                 // This is not really good, we need slasharguments for relative links, this means no caching...
 583                 $path = realpath("$componentdir/jquery/$file");
 584                 if (strpos($path, $CFG->dirroot) === 0) {
 585                     $url = $CFG->wwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 586                     // Replace all occurences of backslashes characters in url to forward slashes.
 587                     $url = str_replace('\\', '/', $url);
 588                     $url = new moodle_url($url);
 589                 } else {
 590                     // Bad luck, fix your server!
 591                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 592                     continue;
 593                 }
 594             }
 595             $this->jqueryplugins[$plugin]->urls[] = $url;
 596         }
 597
 598         return true;
 599     }
 600
 601     /**
 602      * Request replacement of one jQuery plugin by another.
 603      *
 604      * This is useful when themes want to replace the jQuery UI theme,
 605      * the problem is that theme can not prevent others from including the core ui-css plugin.
 606      *
 607      * Example:
 608      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 609      *  2/ write theme/yourtheme/jquery/plugins.php
 610      *  3/ init jQuery from theme
 611      *
 612      * <code>
 613      *   // file theme/yourtheme/lib.php
 614      *   function theme_yourtheme_page_init($page) {
 615      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 616      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 617      *   }
 618      * </code>
 619      *
 620      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 621      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 622      *
 623      * {@see http://docs.moodle.org/dev/jQuery}
 624      *
 625      * @param string $oldplugin original plugin
 626      * @param string $newplugin the replacement
 627      */
 628     public function jquery_override_plugin($oldplugin, $newplugin) {
 629         if ($this->headdone) {
 630             debugging('Can not override jQuery plugins after starting page output!');
 631             return;
 632         }
 633         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 634     }
 635
 636     /**
 637      * Return jQuery related markup for page start.
 638      * @return string
 639      */
 640     protected function get_jquery_headcode() {
 641         if (empty($this->jqueryplugins['jquery'])) {
 642             // If nobody requested jQuery then do not bother to load anything.
 643             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 644             return '';
 645         }
 646
 647         $included = array();
 648         $urls = array();
 649
 650         foreach ($this->jqueryplugins as $name => $unused) {
 651             if (isset($included[$name])) {
 652                 continue;
 653             }
 654             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 655                 // The following loop tries to resolve the replacements,
 656                 // use max 100 iterations to prevent infinite loop resulting
 657                 // in blank page.
 658                 $cyclic = true;
 659                 $oldname = $name;
 660                 for ($i=0; $i<100; $i++) {
 661                     $name = $this->jquerypluginoverrides[$name];
 662                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 663                         $cyclic = false;
 664                         break;
 665                     }
 666                 }
 667                 if ($cyclic) {
 668                     // We can not do much with cyclic references here, let's use the old plugin.
 669                     $name = $oldname;
 670                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 671
 672                 } else if (empty($name)) {
 673                     // Developer requested removal of the plugin.
 674                     continue;
 675
 676                 } else if (!isset($this->jqueryplugins[$name])) {
 677                     debugging("Unknown jQuery override plugin '$name' detected");
 678                     $name = $oldname;
 679
 680                 } else if (isset($included[$name])) {
 681                     // The plugin was already included, easy.
 682                     continue;
 683                 }
 684             }
 685
 686             $plugin = $this->jqueryplugins[$name];
 687             $urls = array_merge($urls, $plugin->urls);
 688             $included[$name] = true;
 689         }
 690
 691         $output = '';
 692         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 693         foreach ($urls as $url) {
 694             if (preg_match('/\.js$/', $url)) {
 695                 $output .= html_writer::script('', $url);
 696             } else if (preg_match('/\.css$/', $url)) {
 697                 $attributes['href'] = $url;
 698                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 699             }
 700         }
 701
 702         return $output;
 703     }
 704
 705     /**
 706      * Returns the actual url through which a JavaScript file is served.
 707      *
 708      * @param moodle_url|string $url full moodle url, or shortened path to script.
 709      * @throws coding_exception if the given $url isn't a shortened url starting with / or a moodle_url instance.
 710      * @return moodle_url
 711      */
 712     protected function js_fix_url($url) {
 713         global $CFG;
 714
 715         if ($url instanceof moodle_url) {
 716             // If the URL is external to Moodle, it won't be handled by Moodle (!).
 717             if ($url->is_local_url()) {
 718                 $localurl = $url->out_as_local_url();
 719                 // Check if the URL points to a Moodle PHP resource.
 720                 if (strpos($localurl, '.php') !== false) {
 721                     // It's a Moodle PHP resource e.g. a resource already served by the proper Moodle Handler.
 722                     return $url;
 723                 }
 724                 // It's a local resource: we need to further examine it.
 725                 return $this->js_fix_url($url->out_as_local_url(false));
 726             }
 727             // The URL is not a Moodle resource.
 728             return $url;
 729         } else if (null !== $url && strpos($url, '/') === 0) {
 730             // Fix the admin links if needed.
 731             if ($CFG->admin !== 'admin') {
 732                 if (strpos($url, "/admin/") === 0) {
 733                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 734                 }
 735             }
 736             if (debugging()) {
 737                 // Check file existence only when in debug mode.
 738                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 739                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 740                 }
 741             }
 742             if (substr($url, -3) === '.js') {
 743                 $jsrev = $this->get_jsrev();
 744                 if (empty($CFG->slasharguments)) {
 745                     return new moodle_url('/lib/javascript.php', ['rev' => $jsrev, 'jsfile' => $url]);
 746                 } else {
 747                     $returnurl = new moodle_url('/lib/javascript.php');
 748                     $returnurl->set_slashargument('/'.$jsrev.$url);
 749                     return $returnurl;
 750                 }
 751             } else {
 752                 return new moodle_url($url);
 753             }
 754         } else {
 755             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 756         }
 757     }
 758
 759     /**
 760      * Find out if JS module present and return details.
 761      *
 762      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 763      * @return array description of module or null if not found
 764      */
 765     protected function find_module($component) {
 766         global $CFG, $PAGE;
 767
 768         $module = null;
 769
 770         if (strpos($component, 'core_') === 0) {
 771             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 772             // so that we do nto have to repeat the definition of these modules over and over again.
 773             switch($component) {
 774                 case 'core_filepicker':
 775                     $module = array('name'     => 'core_filepicker',
 776                                     'fullpath' => '/repository/filepicker.js',
 777                                     'requires' => array(
 778                                         'base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form',
 779                                         'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin',
 780                                         'escape', 'moodle-core_filepicker', 'moodle-core-notification-dialogue'
 781                                     ),
 782                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 783                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 784                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 785                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 786                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 787                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 788                                                         array('referencesexist', 'repository'), array('select', 'repository')
 789                                                     ));
 790                     break;
 791                 case 'core_comment':
 792                     $module = array('name'     => 'core_comment',
 793                                     'fullpath' => '/comment/comment.js',
 794                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay', 'escape'),
 795                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 796                                 );
 797                     break;
 798                 case 'core_role':
 799                     $module = array('name'     => 'core_role',
 800                                     'fullpath' => '/admin/roles/module.js',
 801                                     'requires' => array('node', 'cookie'));
 802                     break;
 803                 case 'core_completion':
 804                     break;
 805                 case 'core_message':
 806                     $module = array('name'     => 'core_message',
 807                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 808                                     'fullpath' => '/message/module.js');
 809                     break;
 810                 case 'core_group':
 811                     $module = array('name'     => 'core_group',
 812                                     'fullpath' => '/group/module.js',
 813                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 814                     break;
 815                 case 'core_question_engine':
 816                     $module = array('name'     => 'core_question_engine',
 817                                     'fullpath' => '/question/qengine.js',
 818                                     'requires' => array('node', 'event'));
 819                     break;
 820                 case 'core_rating':
 821                     $module = array('name'     => 'core_rating',
 822                                     'fullpath' => '/rating/module.js',
 823                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 824                     break;
 825                 case 'core_dndupload':
 826                     $module = array('name'     => 'core_dndupload',
 827                                     'fullpath' => '/lib/form/dndupload.js',
 828                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 829                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 830                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesfile', 'error'),
 831                                                         array('sizegb', 'moodle'), array('sizemb', 'moodle'), array('sizekb', 'moodle'), array('sizeb', 'moodle'),
 832                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 833                                                         array('changesmadereallygoaway', 'moodle'), array('complete', 'moodle')
 834                                                     ));
 835                     break;
 836             }
 837
 838         } else {
 839             if ($dir = core_component::get_component_directory($component)) {
 840                 if (file_exists("$dir/module.js")) {
 841                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 842                         $dir = substr($dir, strlen($CFG->dirroot));
 843                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 844                     }
 845                 }
 846             }
 847         }
 848
 849         return $module;
 850     }
 851
 852     /**
 853      * Append YUI3 module to default YUI3 JS loader.
 854      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 855      *
 856      * @param string|array $module name of module (details are autodetected), or full module specification as array
 857      * @return void
 858      */
 859     public function js_module($module) {
 860         global $CFG;
 861
 862         if (empty($module)) {
 863             throw new coding_exception('Missing YUI3 module name or full description.');
 864         }
 865
 866         if (is_string($module)) {
 867             $module = $this->find_module($module);
 868         }
 869
 870         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 871             throw new coding_exception('Missing YUI3 module details.');
 872         }
 873
 874         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 875         // Add all needed strings.
 876         if (!empty($module['strings'])) {
 877             foreach ($module['strings'] as $string) {
 878                 $identifier = $string[0];
 879                 $component = isset($string[1]) ? $string[1] : 'moodle';
 880                 $a = isset($string[2]) ? $string[2] : null;
 881                 $this->string_for_js($identifier, $component, $a);
 882             }
 883         }
 884         unset($module['strings']);
 885
 886         // Process module requirements and attempt to load each. This allows
 887         // moodle modules to require each other.
 888         if (!empty($module['requires'])){
 889             foreach ($module['requires'] as $requirement) {
 890                 $rmodule = $this->find_module($requirement);
 891                 if (is_array($rmodule)) {
 892                     $this->js_module($rmodule);
 893                 }
 894             }
 895         }
 896
 897         if ($this->headdone) {
 898             $this->extramodules[$module['name']] = $module;
 899         } else {
 900             $this->YUI_config->add_module_config($module['name'], $module);
 901         }
 902     }
 903
 904     /**
 905      * Returns true if the module has already been loaded.
 906      *
 907      * @param string|array $module
 908      * @return bool True if the module has already been loaded
 909      */
 910     protected function js_module_loaded($module) {
 911         if (is_string($module)) {
 912             $modulename = $module;
 913         } else {
 914             $modulename = $module['name'];
 915         }
 916         return array_key_exists($modulename, $this->YUI_config->modules) ||
 917                array_key_exists($modulename, $this->extramodules);
 918     }
 919
 920     /**
 921      * Ensure that the specified CSS file is linked to from this page.
 922      *
 923      * Because stylesheet links must go in the <head> part of the HTML, you must call
 924      * this function before {@link get_head_code()} is called. That normally means before
 925      * the call to print_header. If you call it when it is too late, an exception
 926      * will be thrown.
 927      *
 928      * Even if a particular style sheet is requested more than once, it will only
 929      * be linked to once.
 930      *
 931      * Please note use of this feature is strongly discouraged,
 932      * it is suitable only for places where CSS is submitted directly by teachers.
 933      * (Students must not be allowed to submit any external CSS because it may
 934      * contain embedded javascript!). Example of correct use is mod/data.
 935      *
 936      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 937      *   For example:
 938      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 939      */
 940     public function css($stylesheet) {
 941         global $CFG;
 942
 943         if ($this->headdone) {
 944             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 945         }
 946
 947         if ($stylesheet instanceof moodle_url) {
 948             // ok
 949         } else if (strpos($stylesheet, '/') === 0) {
 950             $stylesheet = new moodle_url($stylesheet);
 951         } else {
 952             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 953         }
 954
 955         $this->cssurls[$stylesheet->out()] = $stylesheet;
 956     }
 957
 958     /**
 959      * Add theme stylesheet to page - do not use from plugin code,
 960      * this should be called only from the core renderer!
 961      *
 962      * @param moodle_url $stylesheet
 963      * @return void
 964      */
 965     public function css_theme(moodle_url $stylesheet) {
 966         $this->cssthemeurls[] = $stylesheet;
 967     }
 968
 969     /**
 970      * Ensure that a skip link to a given target is printed at the top of the <body>.
 971      *
 972      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 973      * will be thrown). That normally means you must call this before the call to print_header.
 974      *
 975      * If you ask for a particular skip link to be printed, it is then your responsibility
 976      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 977      * page, so that the skip link goes somewhere.
 978      *
 979      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 980      *
 981      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 982      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 983      */
 984     public function skip_link_to($target, $linktext) {
 985         if ($this->topofbodydone) {
 986             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 987             return;
 988         }
 989         $this->skiplinks[$target] = $linktext;
 990     }
 991
 992     /**
 993      * !!!DEPRECATED!!! please use js_init_call() if possible
 994      * Ensure that the specified JavaScript function is called from an inline script
 995      * somewhere on this page.
 996      *
 997      * By default the call will be put in a script tag at the
 998      * end of the page after initialising Y instance, since this gives best page-load
 999      * performance and allows you to use YUI3 library.
1000      *
1001      * If you request that a particular function is called several times, then
1002      * that is what will happen (unlike linking to a CSS or JS file, where only
1003      * one link will be output).
1004      *
1005      * The main benefit of the method is the automatic encoding of all function parameters.
1006      *
1007      * @deprecated
1008      *
1009      * @param string $function the name of the JavaScritp function to call. Can
1010      *      be a compound name like 'Y.Event.purgeElement'. Can also be
1011      *      used to create and object by using a 'function name' like 'new user_selector'.
1012      * @param array $arguments and array of arguments to be passed to the function.
1013      *      When generating the function call, this will be escaped using json_encode,
1014      *      so passing objects and arrays should work.
1015      * @param bool $ondomready If tru the function is only called when the dom is
1016      *      ready for manipulation.
1017      * @param int $delay The delay before the function is called.
1018      */
1019     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
1020         $where = $ondomready ? 'ondomready' : 'normal';
1021         $this->jscalls[$where][] = array($function, $arguments, $delay);
1022     }
1023
1024     /**
1025      * This function appends a block of code to the AMD specific javascript block executed
1026      * in the page footer, just after loading the requirejs library.
1027      *
1028      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
1029      *
1030      * @param string $code The JS code to append.
1031      */
1032     public function js_amd_inline($code) {
1033         $this->amdjscode[] = $code;
1034     }
1035
1036     /**
1037      * Load an AMD module and eventually call its method.
1038      *
1039      * This function creates a minimal inline JS snippet that requires an AMD module and eventually calls a single
1040      * function from the module with given arguments. If it is called multiple times, it will be create multiple
1041      * snippets.
1042      *
1043      * @param string $fullmodule The name of the AMD module to load, formatted as <component name>/<module name>.
1044      * @param string $func Optional function from the module to call, defaults to just loading the AMD module.
1045      * @param array $params The params to pass to the function (will be serialized into JSON).
1046      */
1047     public function js_call_amd($fullmodule, $func = null, $params = array()) {
1048         global $CFG;
1049
1050         $modulepath = explode('/', $fullmodule);
1051
1052         $modname = clean_param(array_shift($modulepath), PARAM_COMPONENT);
1053         foreach ($modulepath as $module) {
1054             $modname .= '/' . clean_param($module, PARAM_ALPHANUMEXT);
1055         }
1056
1057         $functioncode = [];
1058         if ($func !== null) {
1059             $func = clean_param($func, PARAM_ALPHANUMEXT);
1060
1061             $jsonparams = array();
1062             foreach ($params as $param) {
1063                 $jsonparams[] = json_encode($param);
1064             }
1065             $strparams = implode(', ', $jsonparams);
1066             if ($CFG->debugdeveloper) {
1067                 $toomanyparamslimit = 1024;
1068                 if (strlen($strparams) > $toomanyparamslimit) {
1069                     debugging('Too much data passed as arguments to js_call_amd("' . $fullmodule . '", "' . $func .
1070                         '"). Generally there are better ways to pass lots of data from PHP to JavaScript, for example via Ajax, ' .
1071                         'data attributes, ... . This warning is triggered if the argument string becomes longer than ' .
1072                         $toomanyparamslimit . ' characters.', DEBUG_DEVELOPER);
1073                 }
1074             }
1075
1076             $functioncode[] = "amd.{$func}({$strparams});";
1077         }
1078
1079         $functioncode[] = "M.util.js_complete('{$modname}');";
1080
1081         $initcode = implode(' ', $functioncode);
1082         $js = "M.util.js_pending('{$modname}'); require(['{$modname}'], function(amd) {{$initcode}});";
1083
1084         $this->js_amd_inline($js);
1085     }
1086
1087     /**
1088      * Creates a JavaScript function call that requires one or more modules to be loaded.
1089      *
1090      * This function can be used to include all of the standard YUI module types within JavaScript:
1091      *     - YUI3 modules    [node, event, io]
1092      *     - YUI2 modules    [yui2-*]
1093      *     - Moodle modules  [moodle-*]
1094      *     - Gallery modules [gallery-*]
1095      *
1096      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1097      * @see js_call_amd()
1098      *
1099      * @param array|string $modules One or more modules
1100      * @param string $function The function to call once modules have been loaded
1101      * @param array $arguments An array of arguments to pass to the function
1102      * @param string $galleryversion Deprecated: The gallery version to use
1103      * @param bool $ondomready
1104      */
1105     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1106         if (!is_array($modules)) {
1107             $modules = array($modules);
1108         }
1109
1110         if ($galleryversion != null) {
1111             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1112         }
1113
1114         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1115         if ($ondomready) {
1116             $jscode = "Y.on('domready', function() { $jscode });";
1117         }
1118         $this->jsinitcode[] = $jscode;
1119     }
1120
1121     /**
1122      * Set the CSS Modules to be included from YUI.
1123      *
1124      * @param array $modules The list of YUI CSS Modules to include.
1125      */
1126     public function set_yuicssmodules(array $modules = array()) {
1127         $this->yuicssmodules = $modules;
1128     }
1129
1130     /**
1131      * Ensure that the specified JavaScript function is called from an inline script
1132      * from page footer.
1133      *
1134      * @param string $function the name of the JavaScritp function to with init code,
1135      *      usually something like 'M.mod_mymodule.init'
1136      * @param array $extraarguments and array of arguments to be passed to the function.
1137      *      The first argument is always the YUI3 Y instance with all required dependencies
1138      *      already loaded.
1139      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1140      * @param array $module JS module specification array
1141      */
1142     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1143         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1144         if (!$module) {
1145             // Detect module automatically.
1146             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1147                 $module = $this->find_module($matches[1]);
1148             }
1149         }
1150
1151         $this->js_init_code($jscode, $ondomready, $module);
1152     }
1153
1154     /**
1155      * Add short static javascript code fragment to page footer.
1156      * This is intended primarily for loading of js modules and initialising page layout.
1157      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1158      * may override it.
1159      *
1160      * @param string $jscode
1161      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1162      * @param array $module JS module specification array
1163      */
1164     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1165         $jscode = trim($jscode, " ;\n"). ';';
1166
1167         $uniqid = html_writer::random_id();
1168         $startjs = " M.util.js_pending('" . $uniqid . "');";
1169         $endjs = " M.util.js_complete('" . $uniqid . "');";
1170
1171         if ($module) {
1172             $this->js_module($module);
1173             $modulename = $module['name'];
1174             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1175         }
1176
1177         if ($ondomready) {
1178             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1179         }
1180
1181         $this->jsinitcode[] = $jscode;
1182     }
1183
1184     /**
1185      * Make a language string available to JavaScript.
1186      *
1187      * All the strings will be available in a M.str object in the global namespace.
1188      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1189      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1190      * equivalent in the current language.
1191      *
1192      * The arguments to this function are just like the arguments to get_string
1193      * except that $component is not optional, and there are some aspects to consider
1194      * when the string contains {$a} placeholder.
1195      *
1196      * If the string does not contain any {$a} placeholder, you can simply use
1197      * M.str.component.identifier to obtain it. If you prefer, you can call
1198      * M.util.get_string(identifier, component) to get the same result.
1199      *
1200      * If you need to use {$a} placeholders, there are two options. Either the
1201      * placeholder should be substituted in PHP on server side or it should
1202      * be substituted in Javascript at client side.
1203      *
1204      * To substitute the placeholder at server side, just provide the required
1205      * value for the placeholder when you require the string. Because each string
1206      * is only stored once in the JavaScript (based on $identifier and $module)
1207      * you cannot get the same string with two different values of $a. If you try,
1208      * an exception will be thrown. Once the placeholder is substituted, you can
1209      * use M.str or M.util.get_string() as shown above:
1210      *
1211      *     // Require the string in PHP and replace the placeholder.
1212      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1213      *     // Use the result of the substitution in Javascript.
1214      *     alert(M.str.moodle.fullnamedisplay);
1215      *
1216      * To substitute the placeholder at client side, use M.util.get_string()
1217      * function. It implements the same logic as {@link get_string()}:
1218      *
1219      *     // Require the string in PHP but keep {$a} as it is.
1220      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1221      *     // Provide the values on the fly in Javascript.
1222      *     user = { firstname : 'Harry', lastname : 'Potter' }
1223      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1224      *
1225      * If you do need the same string expanded with different $a values in PHP
1226      * on server side, then the solution is to put them in your own data structure
1227      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1228      *
1229      * @param string $identifier the desired string.
1230      * @param string $component the language file to look in.
1231      * @param mixed $a any extra data to add into the string (optional).
1232      */
1233     public function string_for_js($identifier, $component, $a = null) {
1234         if (!$component) {
1235             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1236         }
1237         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1238             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1239                     "from lang file '$component' with different \$a parameter?");
1240         }
1241         if (!isset($this->stringsforjs[$component][$identifier])) {
1242             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1243             $this->stringsforjs_as[$component][$identifier] = $a;
1244         }
1245     }
1246
1247     /**
1248      * Make an array of language strings available for JS.
1249      *
1250      * This function calls the above function {@link string_for_js()} for each requested
1251      * string in the $identifiers array that is passed to the argument for a single module
1252      * passed in $module.
1253      *
1254      * <code>
1255      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1256      *
1257      * // The above is identical to calling:
1258      *
1259      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1260      * $PAGE->requires->string_for_js('two', 'mymod');
1261      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1262      * </code>
1263      *
1264      * @param array $identifiers An array of desired strings
1265      * @param string $component The module to load for
1266      * @param mixed $a This can either be a single variable that gets passed as extra
1267      *         information for every string or it can be an array of mixed data where the
1268      *         key for the data matches that of the identifier it is meant for.
1269      *
1270      */
1271     public function strings_for_js($identifiers, $component, $a = null) {
1272         foreach ($identifiers as $key => $identifier) {
1273             if (is_array($a) && array_key_exists($key, $a)) {
1274                 $extra = $a[$key];
1275             } else {
1276                 $extra = $a;
1277             }
1278             $this->string_for_js($identifier, $component, $extra);
1279         }
1280     }
1281
1282     /**
1283      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1284      *
1285      * Make some data from PHP available to JavaScript code.
1286      *
1287      * For example, if you call
1288      * <pre>
1289      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1290      * </pre>
1291      * then in JavsScript mydata.name will be 'Moodle'.
1292      *
1293      * @deprecated
1294      * @param string $variable the the name of the JavaScript variable to assign the data to.
1295      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1296      *      should be considered an experimental feature.
1297      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1298      *      so passing objects and arrays should work.
1299      * @param bool $inhead initialise in head
1300      * @return void
1301      */
1302     public function data_for_js($variable, $data, $inhead=false) {
1303         $where = $inhead ? 'head' : 'footer';
1304         $this->jsinitvariables[$where][] = array($variable, $data);
1305     }
1306
1307     /**
1308      * Creates a YUI event handler.
1309      *
1310      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1311      * @param string $event A valid DOM event (click, mousedown, change etc.)
1312      * @param string $function The name of the function to call
1313      * @param array  $arguments An optional array of argument parameters to pass to the function
1314      */
1315     public function event_handler($selector, $event, $function, array $arguments = null) {
1316         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1317     }
1318
1319     /**
1320      * Returns code needed for registering of event handlers.
1321      * @return string JS code
1322      */
1323     protected function get_event_handler_code() {
1324         $output = '';
1325         foreach ($this->eventhandlers as $h) {
1326             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1327         }
1328         return $output;
1329     }
1330
1331     /**
1332      * Get the inline JavaScript code that need to appear in a particular place.
1333      * @param bool $ondomready
1334      * @return string
1335      */
1336     protected function get_javascript_code($ondomready) {
1337         $where = $ondomready ? 'ondomready' : 'normal';
1338         $output = '';
1339         if ($this->jscalls[$where]) {
1340             foreach ($this->jscalls[$where] as $data) {
1341                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1342             }
1343             if (!empty($ondomready)) {
1344                 $output = "    Y.on('domready', function() {\n$output\n});";
1345             }
1346         }
1347         return $output;
1348     }
1349
1350     /**
1351      * Returns js code to be executed when Y is available.
1352      * @return string
1353      */
1354     protected function get_javascript_init_code() {
1355         if (count($this->jsinitcode)) {
1356             return implode("\n", $this->jsinitcode) . "\n";
1357         }
1358         return '';
1359     }
1360
1361     /**
1362      * Returns js code to load amd module loader, then insert inline script tags
1363      * that contain require() calls using RequireJS.
1364      * @return string
1365      */
1366     protected function get_amd_footercode() {
1367         global $CFG;
1368         $output = '';
1369
1370         // We will cache JS if cachejs is not set, or it is true.
1371         $cachejs = !isset($CFG->cachejs) || $CFG->cachejs;
1372         $jsrev = $this->get_jsrev();
1373
1374         $jsloader = new moodle_url('/lib/javascript.php');
1375         $jsloader->set_slashargument('/' . $jsrev . '/');
1376         $requirejsloader = new moodle_url('/lib/requirejs.php');
1377         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1378
1379         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1380
1381         // No extension required unless slash args is disabled.
1382         $jsextension = '.js';
1383         if (!empty($CFG->slasharguments)) {
1384             $jsextension = '';
1385         }
1386
1387         $minextension = '.min';
1388         if (!$cachejs) {
1389             $minextension = '';
1390         }
1391
1392         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1393         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1394         $requirejsconfig = str_replace('[JSMIN]', $minextension, $requirejsconfig);
1395         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1396
1397         $output .= html_writer::script($requirejsconfig);
1398         if ($cachejs) {
1399             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1400         } else {
1401             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1402         }
1403
1404         // First include must be to a module with no dependencies, this prevents multiple requests.
1405         $prefix = <<<EOF
1406 M.util.js_pending("core/first");
1407 require(['core/first'], function() {
1408
1409 EOF;
1410
1411         if (during_initial_install()) {
1412             // Do not run a prefetch during initial install as the DB is not available to service WS calls.
1413             $prefetch = '';
1414         } else {
1415             $prefetch = "require(['core/prefetch'])\n";
1416         }
1417
1418         $suffix = <<<EOF
1419
1420     M.util.js_complete("core/first");
1421 });
1422 EOF;
1423
1424         $output .= html_writer::script($prefix . $prefetch . implode(";\n", $this->amdjscode) . $suffix);
1425         return $output;
1426     }
1427
1428     /**
1429      * Returns basic YUI3 CSS code.
1430      *
1431      * @return string
1432      */
1433     protected function get_yui3lib_headcss() {
1434         global $CFG;
1435
1436         $yuiformat = '-min';
1437         if ($this->yui3loader->filter === 'RAW') {
1438             $yuiformat = '';
1439         }
1440
1441         $code = '';
1442         if ($this->yui3loader->combine) {
1443             if (!empty($this->yuicssmodules)) {
1444                 $modules = array();
1445                 foreach ($this->yuicssmodules as $module) {
1446                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1447                 }
1448                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1449             }
1450             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1451
1452         } else {
1453             if (!empty($this->yuicssmodules)) {
1454                 foreach ($this->yuicssmodules as $module) {
1455                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1456                 }
1457             }
1458             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1459         }
1460
1461         if ($this->yui3loader->filter === 'RAW') {
1462             $code = str_replace('-min.css', '.css', $code);
1463         } else if ($this->yui3loader->filter === 'DEBUG') {
1464             $code = str_replace('-min.css', '.css', $code);
1465         }
1466         return $code;
1467     }
1468
1469     /**
1470      * Returns basic YUI3 JS loading code.
1471      *
1472      * @return string
1473      */
1474     protected function get_yui3lib_headcode() {
1475         global $CFG;
1476
1477         $jsrev = $this->get_jsrev();
1478
1479         $yuiformat = '-min';
1480         if ($this->yui3loader->filter === 'RAW') {
1481             $yuiformat = '';
1482         }
1483
1484         $format = '-min';
1485         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1486             $format = '-debug';
1487         }
1488
1489         $rollupversion = $CFG->yui3version;
1490         if (!empty($CFG->yuipatchlevel)) {
1491             $rollupversion .= '_' . $CFG->yuipatchlevel;
1492         }
1493
1494         $baserollups = array(
1495             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1496         );
1497
1498         if ($this->yui3loader->combine) {
1499             return '<script src="' .
1500                     $this->yui3loader->local_comboBase .
1501                     implode('&amp;', $baserollups) .
1502                     '"></script>';
1503         } else {
1504             $code = '';
1505             foreach ($baserollups as $rollup) {
1506                 $code .= '<script src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1507             }
1508             return $code;
1509         }
1510
1511     }
1512
1513     /**
1514      * Returns html tags needed for inclusion of theme CSS.
1515      *
1516      * @return string
1517      */
1518     protected function get_css_code() {
1519         // First of all the theme CSS, then any custom CSS
1520         // Please note custom CSS is strongly discouraged,
1521         // because it can not be overridden by themes!
1522         // It is suitable only for things like mod/data which accepts CSS from teachers.
1523         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1524
1525         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1526         $code = $this->get_yui3lib_headcss();
1527
1528         // This line of code may look funny but it is currently required in order
1529         // to avoid MASSIVE display issues in Internet Explorer.
1530         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1531         // ignored whenever another resource is added until such time as a redraw
1532         // is forced, usually by moving the mouse over the affected element.
1533         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1534
1535         $urls = $this->cssthemeurls + $this->cssurls;
1536         foreach ($urls as $url) {
1537             $attributes['href'] = $url;
1538             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1539             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1540             unset($attributes['id']);
1541         }
1542
1543         return $code;
1544     }
1545
1546     /**
1547      * Adds extra modules specified after printing of page header.
1548      *
1549      * @return string
1550      */
1551     protected function get_extra_modules_code() {
1552         if (empty($this->extramodules)) {
1553             return '';
1554         }
1555         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1556     }
1557
1558     /**
1559      * Generate any HTML that needs to go inside the <head> tag.
1560      *
1561      * Normally, this method is called automatically by the code that prints the
1562      * <head> tag. You should not normally need to call it in your own code.
1563      *
1564      * @param moodle_page $page
1565      * @param core_renderer $renderer
1566      * @return string the HTML code to to inside the <head> tag.
1567      */
1568     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1569         global $CFG;
1570
1571         // Note: the $page and $output are not stored here because it would
1572         // create circular references in memory which prevents garbage collection.
1573         $this->init_requirements_data($page, $renderer);
1574
1575         $output = '';
1576
1577         // Add all standard CSS for this page.
1578         $output .= $this->get_css_code();
1579
1580         // Set up the M namespace.
1581         $js = "var M = {}; M.yui = {};\n";
1582
1583         // Capture the time now ASAP during page load. This minimises the lag when
1584         // we try to relate times on the server to times in the browser.
1585         // An example of where this is used is the quiz countdown timer.
1586         $js .= "M.pageloadstarttime = new Date();\n";
1587
1588         // Add a subset of Moodle configuration to the M namespace.
1589         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1590
1591         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1592         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1593         //       this needs to be done before including any other script.
1594         $js .= $this->YUI_config->get_config_functions();
1595         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1596         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1597         $js = $this->YUI_config->update_header_js($js);
1598
1599         $output .= html_writer::script($js);
1600
1601         // Add variables.
1602         if ($this->jsinitvariables['head']) {
1603             $js = '';
1604             foreach ($this->jsinitvariables['head'] as $data) {
1605                 list($var, $value) = $data;
1606                 $js .= js_writer::set_variable($var, $value, true);
1607             }
1608             $output .= html_writer::script($js);
1609         }
1610
1611         // Mark head sending done, it is not possible to anything there.
1612         $this->headdone = true;
1613
1614         return $output;
1615     }
1616
1617     /**
1618      * Generate any HTML that needs to go at the start of the <body> tag.
1619      *
1620      * Normally, this method is called automatically by the code that prints the
1621      * <head> tag. You should not normally need to call it in your own code.
1622      *
1623      * @param renderer_base $renderer
1624      * @return string the HTML code to go at the start of the <body> tag.
1625      */
1626     public function get_top_of_body_code(renderer_base $renderer) {
1627         global $CFG;
1628
1629         // First the skip links.
1630         $output = $renderer->render_skip_links($this->skiplinks);
1631
1632         // Include the Polyfills.
1633         $output .= html_writer::script('', $this->js_fix_url('/lib/polyfills/polyfill.js'));
1634
1635         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1636         $output .= $this->get_yui3lib_headcode();
1637
1638         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1639         $output .= $this->get_jquery_headcode();
1640
1641         // Link our main JS file, all core stuff should be there.
1642         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1643
1644         // All the other linked things from HEAD - there should be as few as possible.
1645         if ($this->jsincludes['head']) {
1646             foreach ($this->jsincludes['head'] as $url) {
1647                 $output .= html_writer::script('', $url);
1648             }
1649         }
1650
1651         // Then the clever trick for hiding of things not needed when JS works.
1652         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1653         $this->topofbodydone = true;
1654         return $output;
1655     }
1656
1657     /**
1658      * Generate any HTML that needs to go at the end of the page.
1659      *
1660      * Normally, this method is called automatically by the code that prints the
1661      * page footer. You should not normally need to call it in your own code.
1662      *
1663      * @return string the HTML code to to at the end of the page.
1664      */
1665     public function get_end_code() {
1666         global $CFG;
1667         $output = '';
1668
1669         // Set the log level for the JS logging.
1670         $logconfig = new stdClass();
1671         $logconfig->level = 'warn';
1672         if ($CFG->debugdeveloper) {
1673             $logconfig->level = 'trace';
1674         }
1675         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1676         // Add any global JS that needs to run on all pages.
1677         $this->js_call_amd('core/page_global', 'init');
1678         $this->js_call_amd('core/utility');
1679
1680         // Call amd init functions.
1681         $output .= $this->get_amd_footercode();
1682
1683         // Add other requested modules.
1684         $output .= $this->get_extra_modules_code();
1685
1686         $this->js_init_code('M.util.js_complete("init");', true);
1687
1688         // All the other linked scripts - there should be as few as possible.
1689         if ($this->jsincludes['footer']) {
1690             foreach ($this->jsincludes['footer'] as $url) {
1691                 $output .= html_writer::script('', $url);
1692             }
1693         }
1694
1695         // Add all needed strings.
1696         // First add core strings required for some dialogues.
1697         $this->strings_for_js(array(
1698             'confirm',
1699             'yes',
1700             'no',
1701             'areyousure',
1702             'closebuttontitle',
1703             'unknownerror',
1704             'error',
1705             'file',
1706             'url',
1707             // TODO MDL-70830 shortforms should preload the collapseall/expandall strings properly.
1708             'collapseall',
1709             'expandall',
1710         ), 'moodle');
1711         $this->strings_for_js(array(
1712             'debuginfo',
1713             'line',
1714             'stacktrace',
1715         ), 'debug');
1716         $this->string_for_js('labelsep', 'langconfig');
1717         if (!empty($this->stringsforjs)) {
1718             $strings = array();
1719             foreach ($this->stringsforjs as $component=>$v) {
1720                 foreach($v as $indentifier => $langstring) {
1721                     $strings[$component][$indentifier] = $langstring->out();
1722                 }
1723             }
1724             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1725         }
1726
1727         // Add variables.
1728         if ($this->jsinitvariables['footer']) {
1729             $js = '';
1730             foreach ($this->jsinitvariables['footer'] as $data) {
1731                 list($var, $value) = $data;
1732                 $js .= js_writer::set_variable($var, $value, true);
1733             }
1734             $output .= html_writer::script($js);
1735         }
1736
1737         $inyuijs = $this->get_javascript_code(false);
1738         $ondomreadyjs = $this->get_javascript_code(true);
1739         $jsinit = $this->get_javascript_init_code();
1740         $handlersjs = $this->get_event_handler_code();
1741
1742         // There is a global Y, make sure it is available in your scope.
1743         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1744
1745         $output .= html_writer::script($js);
1746
1747         return $output;
1748     }
1749
1750     /**
1751      * Have we already output the code in the <head> tag?
1752      *
1753      * @return bool
1754      */
1755     public function is_head_done() {
1756         return $this->headdone;
1757     }
1758
1759     /**
1760      * Have we already output the code at the start of the <body> tag?
1761      *
1762      * @return bool
1763      */
1764     public function is_top_of_body_done() {
1765         return $this->topofbodydone;
1766     }
1767
1768     /**
1769      * Should we generate a bit of content HTML that is only required once  on
1770      * this page (e.g. the contents of the modchooser), now? Basically, we call
1771      * {@link has_one_time_item_been_created()}, and if the thing has not already
1772      * been output, we return true to tell the caller to generate it, and also
1773      * call {@link set_one_time_item_created()} to record the fact that it is
1774      * about to be generated.
1775      *
1776      * That is, a typical usage pattern (in a renderer method) is:
1777      * <pre>
1778      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1779      *     return '';
1780      * }
1781      * // Else generate it.
1782      * </pre>
1783      *
1784      * @param string $thing identifier for the bit of content. Should be of the form
1785      *      frankenstyle_things, e.g. core_course_modchooser.
1786      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1787      */
1788     public function should_create_one_time_item_now($thing) {
1789         if ($this->has_one_time_item_been_created($thing)) {
1790             return false;
1791         }
1792
1793         $this->set_one_time_item_created($thing);
1794         return true;
1795     }
1796
1797     /**
1798      * Has a particular bit of HTML that is only required once  on this page
1799      * (e.g. the contents of the modchooser) already been generated?
1800      *
1801      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1802      * method rather than calling this method directly.
1803      *
1804      * @param string $thing identifier for the bit of content. Should be of the form
1805      *      frankenstyle_things, e.g. core_course_modchooser.
1806      * @return bool whether that bit of output has been created.
1807      */
1808     public function has_one_time_item_been_created($thing) {
1809         return isset($this->onetimeitemsoutput[$thing]);
1810     }
1811
1812     /**
1813      * Indicate that a particular bit of HTML that is only required once on this
1814      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1815      *
1816      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1817      * method rather than calling this method directly.
1818      *
1819      * @param string $thing identifier for the bit of content. Should be of the form
1820      *      frankenstyle_things, e.g. core_course_modchooser.
1821      */
1822     public function set_one_time_item_created($thing) {
1823         if ($this->has_one_time_item_been_created($thing)) {
1824             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1825                     'once per page, but it seems to be being output again.');
1826         }
1827         return $this->onetimeitemsoutput[$thing] = true;
1828     }
1829 }
1830
1831 /**
1832  * This class represents the YUI configuration.
1833  *
1834  * @copyright 2013 Andrew Nicols
1835  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1836  * @since Moodle 2.5
1837  * @package core
1838  * @category output
1839  */
1840 class YUI_config {
1841     /**
1842      * These settings must be public so that when the object is converted to json they are exposed.
1843      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1844      *
1845      * The settings are described and documented in the YUI API at:
1846      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1847      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1848      */
1849     public $debug = false;
1850     public $base;
1851     public $comboBase;
1852     public $combine;
1853     public $filter = null;
1854     public $insertBefore = 'firstthemesheet';
1855     public $groups = array();
1856     public $modules = array();
1857
1858     /**
1859      * @var array List of functions used by the YUI Loader group pattern recognition.
1860      */
1861     protected $jsconfigfunctions = array();
1862
1863     /**
1864      * Create a new group within the YUI_config system.
1865      *
1866      * @param String $name The name of the group. This must be unique and
1867      * not previously used.
1868      * @param Array $config The configuration for this group.
1869      * @return void
1870      */
1871     public function add_group($name, $config) {
1872         if (isset($this->groups[$name])) {
1873             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1874         }
1875         $this->groups[$name] = $config;
1876     }
1877
1878     /**
1879      * Update an existing group configuration
1880      *
1881      * Note, any existing configuration for that group will be wiped out.
1882      * This includes module configuration.
1883      *
1884      * @param String $name The name of the group. This must be unique and
1885      * not previously used.
1886      * @param Array $config The configuration for this group.
1887      * @return void
1888      */
1889     public function update_group($name, $config) {
1890         if (!isset($this->groups[$name])) {
1891             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.');
1892         }
1893         $this->groups[$name] = $config;
1894     }
1895
1896     /**
1897      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1898      *
1899      * Only the body of the function should be passed, and not the whole function wrapper.
1900      *
1901      * The JS function your write will be passed a single argument 'name' containing the
1902      * name of the module being loaded.
1903      *
1904      * @param $function String the body of the JavaScript function. This should be used i
1905      * @return String the name of the function to use in the group pattern configuration.
1906      */
1907     public function set_config_function($function) {
1908         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1909         if (isset($this->jsconfigfunctions[$configname])) {
1910             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1911         }
1912         $this->jsconfigfunctions[$configname] = $function;
1913         return '@' . $configname . '@';
1914     }
1915
1916     /**
1917      * Allow setting of the config function described in {@see set_config_function} from a file.
1918      * The contents of this file are then passed to set_config_function.
1919      *
1920      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1921      *
1922      * @param $file The path to the JavaScript function used for YUI configuration.
1923      * @return String the name of the function to use in the group pattern configuration.
1924      */
1925     public function set_config_source($file) {
1926         global $CFG;
1927         $cache = cache::make('core', 'yuimodules');
1928
1929         // Attempt to get the metadata from the cache.
1930         $keyname = 'configfn_' . $file;
1931         $fullpath = $CFG->dirroot . '/' . $file;
1932         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1933             $cache->delete($keyname);
1934             $configfn = file_get_contents($fullpath);
1935         } else {
1936             $configfn = $cache->get($keyname);
1937             if ($configfn === false) {
1938                 require_once($CFG->libdir . '/jslib.php');
1939                 $configfn = core_minify::js_files(array($fullpath));
1940                 $cache->set($keyname, $configfn);
1941             }
1942         }
1943         return $this->set_config_function($configfn);
1944     }
1945
1946     /**
1947      * Retrieve the list of JavaScript functions for YUI_config groups.
1948      *
1949      * @return String The complete set of config functions
1950      */
1951     public function get_config_functions() {
1952         $configfunctions = '';
1953         foreach ($this->jsconfigfunctions as $functionname => $function) {
1954             $configfunctions .= "var {$functionname} = function(me) {";
1955             $configfunctions .= $function;
1956             $configfunctions .= "};\n";
1957         }
1958         return $configfunctions;
1959     }
1960
1961     /**
1962      * Update the header JavaScript with any required modification for the YUI Loader.
1963      *
1964      * @param $js String The JavaScript to manipulate.
1965      * @return String the modified JS string.
1966      */
1967     public function update_header_js($js) {
1968         // Update the names of the the configFn variables.
1969         // The PHP json_encode function cannot handle literal names so we have to wrap
1970         // them in @ and then replace them with literals of the same function name.
1971         foreach ($this->jsconfigfunctions as $functionname => $function) {
1972             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1973         }
1974         return $js;
1975     }
1976
1977     /**
1978      * Add configuration for a specific module.
1979      *
1980      * @param String $name The name of the module to add configuration for.
1981      * @param Array $config The configuration for the specified module.
1982      * @param String $group The name of the group to add configuration for.
1983      * If not specified, then this module is added to the global
1984      * configuration.
1985      * @return void
1986      */
1987     public function add_module_config($name, $config, $group = null) {
1988         if ($group) {
1989             if (!isset($this->groups[$name])) {
1990                 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.');
1991             }
1992             if (!isset($this->groups[$group]['modules'])) {
1993                 $this->groups[$group]['modules'] = array();
1994             }
1995             $modules = &$this->groups[$group]['modules'];
1996         } else {
1997             $modules = &$this->modules;
1998         }
1999         $modules[$name] = $config;
2000     }
2001
2002     /**
2003      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
2004      *
2005      * If js caching is disabled, metadata will not be served causing YUI to calculate
2006      * module dependencies as each module is loaded.
2007      *
2008      * If metadata does not exist it will be created and stored in a MUC entry.
2009      *
2010      * @return void
2011      */
2012     public function add_moodle_metadata() {
2013         global $CFG;
2014         if (!isset($this->groups['moodle'])) {
2015             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.');
2016         }
2017
2018         if (!isset($this->groups['moodle']['modules'])) {
2019             $this->groups['moodle']['modules'] = array();
2020         }
2021
2022         $cache = cache::make('core', 'yuimodules');
2023         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
2024             $metadata = array();
2025             $metadata = $this->get_moodle_metadata();
2026             $cache->delete('metadata');
2027         } else {
2028             // Attempt to get the metadata from the cache.
2029             if (!$metadata = $cache->get('metadata')) {
2030                 $metadata = $this->get_moodle_metadata();
2031                 $cache->set('metadata', $metadata);
2032             }
2033         }
2034
2035         // Merge with any metadata added specific to this page which was added manually.
2036         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
2037                 $metadata);
2038     }
2039
2040     /**
2041      * Determine the module metadata for all moodle YUI modules.
2042      *
2043      * This works through all modules capable of serving YUI modules, and attempts to get
2044      * metadata for each of those modules.
2045      *
2046      * @return Array of module metadata
2047      */
2048     private function get_moodle_metadata() {
2049         $moodlemodules = array();
2050         // Core isn't a plugin type or subsystem - handle it seperately.
2051         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
2052             $moodlemodules = array_merge($moodlemodules, $module);
2053         }
2054
2055         // Handle other core subsystems.
2056         $subsystems = core_component::get_core_subsystems();
2057         foreach ($subsystems as $subsystem => $path) {
2058             if (is_null($path)) {
2059                 continue;
2060             }
2061             if ($module = $this->get_moodle_path_metadata($path)) {
2062                 $moodlemodules = array_merge($moodlemodules, $module);
2063             }
2064         }
2065
2066         // And finally the plugins.
2067         $plugintypes = core_component::get_plugin_types();
2068         foreach ($plugintypes as $plugintype => $pathroot) {
2069             $pluginlist = core_component::get_plugin_list($plugintype);
2070             foreach ($pluginlist as $plugin => $path) {
2071                 if ($module = $this->get_moodle_path_metadata($path)) {
2072                     $moodlemodules = array_merge($moodlemodules, $module);
2073                 }
2074             }
2075         }
2076
2077         return $moodlemodules;
2078     }
2079
2080     /**
2081      * Helper function process and return the YUI metadata for all of the modules under the specified path.
2082      *
2083      * @param String $path the UNC path to the YUI src directory.
2084      * @return Array the complete array for frankenstyle directory.
2085      */
2086     private function get_moodle_path_metadata($path) {
2087         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
2088         $baseyui = $path . '/yui/src';
2089         $modules = array();
2090         if (is_dir($baseyui)) {
2091             $items = new DirectoryIterator($baseyui);
2092             foreach ($items as $item) {
2093                 if ($item->isDot() or !$item->isDir()) {
2094                     continue;
2095                 }
2096                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
2097                 if (!is_readable($metafile)) {
2098                     continue;
2099                 }
2100                 $metadata = file_get_contents($metafile);
2101                 $modules = array_merge($modules, (array) json_decode($metadata));
2102             }
2103         }
2104         return $modules;
2105     }
2106
2107     /**
2108      * Define YUI modules which we have been required to patch between releases.
2109      *
2110      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2111      * external CDN which will serve the true authoritative copy of the code without our patches.
2112      *
2113      * @param String combobase The local combobase
2114      * @param String yuiversion The current YUI version
2115      * @param Int patchlevel The patch level we're working to for YUI
2116      * @param Array patchedmodules An array containing the names of the patched modules
2117      * @return void
2118      */
2119     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2120         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2121         $subversion = $yuiversion . '_' . $patchlevel;
2122
2123         if ($this->comboBase == $combobase) {
2124             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2125             // loader. We just need to specify a different root which includes a slightly different YUI version number
2126             // to include our patchlevel.
2127             $patterns = array();
2128             $modules = array();
2129             foreach ($patchedmodules as $modulename) {
2130                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2131                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2132                 // loaded when the module is loaded anyway.
2133                 $patterns[$modulename] = array(
2134                     'group' => 'yui-patched',
2135                 );
2136                 $modules[$modulename] = array();
2137             }
2138
2139             // Actually add the patch group here.
2140             $this->add_group('yui-patched', array(
2141                 'combine' => true,
2142                 'root' => $subversion . '/',
2143                 'patterns' => $patterns,
2144                 'modules' => $modules,
2145             ));
2146
2147         } else {
2148             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2149             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2150             // local base in browser caches.
2151             $fullpathbase = $combobase . $subversion . '/';
2152             foreach ($patchedmodules as $modulename) {
2153                 $this->modules[$modulename] = array(
2154                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2155                 );
2156             }
2157         }
2158     }
2159 }
2160
2161 /**
2162  * Invalidate all server and client side template caches.
2163  */
2164 function template_reset_all_caches() {
2165     global $CFG;
2166
2167     $next = time();
2168     if (isset($CFG->templaterev) and $next <= $CFG->templaterev and $CFG->templaterev - $next < 60 * 60) {
2169         // This resolves problems when reset is requested repeatedly within 1s,
2170         // the < 1h condition prevents accidental switching to future dates
2171         // because we might not recover from it.
2172         $next = $CFG->templaterev + 1;
2173     }
2174
2175     set_config('templaterev', $next);
2176 }
2177
2178 /**
2179  * Invalidate all server and client side JS caches.
2180  */
2181 function js_reset_all_caches() {
2182     global $CFG;
2183
2184     $next = time();
2185     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2186         // This resolves problems when reset is requested repeatedly within 1s,
2187         // the < 1h condition prevents accidental switching to future dates
2188         // because we might not recover from it.
2189         $next = $CFG->jsrev+1;
2190     }
2191
2192     set_config('jsrev', $next);
2193 }