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      = $this->yui3loader->combine;
 199
 200         // If we've had to patch any YUI modules between releases, we must override the YUI configuration to include them.
 201         if (!empty($CFG->yuipatchedmodules) && !empty($CFG->yuipatchlevel)) {
 202             $this->YUI_config->define_patched_core_modules($this->yui3loader->local_comboBase,
 203                     $CFG->yui3version,
 204                     $CFG->yuipatchlevel,
 205                     $CFG->yuipatchedmodules);
 206         }
 207
 208         $configname = $this->YUI_config->set_config_source('lib/yui/config/yui2.js');
 209         $this->YUI_config->add_group('yui2', array(
 210             // Loader configuration for our 2in3.
 211             'base' => $CFG->wwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 212             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 213             'combine' => $this->yui3loader->combine,
 214             'ext' => false,
 215             'root' => '2in3/' . $CFG->yui2version .'/build/',
 216             'patterns' => array(
 217                 'yui2-' => array(
 218                     'group' => 'yui2',
 219                     'configFn' => $configname,
 220                 )
 221             )
 222         ));
 223         $configname = $this->YUI_config->set_config_source('lib/yui/config/moodle.js');
 224         $this->YUI_config->add_group('moodle', array(
 225             'name' => 'moodle',
 226             'base' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep . 'm/' . $jsrev . '/',
 227             'combine' => $this->yui3loader->combine,
 228             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 229             'ext' => false,
 230             'root' => 'm/'.$jsrev.'/', // Add the rev to the root path so that we can control caching.
 231             'patterns' => array(
 232                 'moodle-' => array(
 233                     'group' => 'moodle',
 234                     'configFn' => $configname,
 235                 )
 236             )
 237         ));
 238
 239         $this->YUI_config->add_group('gallery', array(
 240             'name' => 'gallery',
 241             'base' => $CFG->wwwroot . '/lib/yuilib/gallery/',
 242             'combine' => $this->yui3loader->combine,
 243             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep,
 244             'ext' => false,
 245             'root' => 'gallery/' . $jsrev . '/',
 246             'patterns' => array(
 247                 'gallery-' => array(
 248                     'group' => 'gallery',
 249                 )
 250             )
 251         ));
 252
 253         // Set some more loader options applying to groups too.
 254         if ($CFG->debugdeveloper) {
 255             // When debugging is enabled, we want to load the non-minified (RAW) versions of YUI library modules rather
 256             // than the DEBUG versions as these generally generate too much logging for our purposes.
 257             // However we do want the DEBUG versions of our Moodle-specific modules.
 258             // To debug a YUI-specific issue, change the yui3loader->filter value to DEBUG.
 259             $this->YUI_config->filter = 'RAW';
 260             $this->YUI_config->groups['moodle']['filter'] = 'DEBUG';
 261
 262             // We use the yui3loader->filter setting when writing the YUI3 seed scripts into the header.
 263             $this->yui3loader->filter = $this->YUI_config->filter;
 264             $this->YUI_config->debug = true;
 265         } else {
 266             $this->yui3loader->filter = null;
 267             $this->YUI_config->groups['moodle']['filter'] = null;
 268             $this->YUI_config->debug = false;
 269         }
 270
 271         // Include the YUI config log filters.
 272         if (!empty($CFG->yuilogexclude) && is_array($CFG->yuilogexclude)) {
 273             $this->YUI_config->logExclude = $CFG->yuilogexclude;
 274         }
 275         if (!empty($CFG->yuiloginclude) && is_array($CFG->yuiloginclude)) {
 276             $this->YUI_config->logInclude = $CFG->yuiloginclude;
 277         }
 278         if (!empty($CFG->yuiloglevel)) {
 279             $this->YUI_config->logLevel = $CFG->yuiloglevel;
 280         }
 281
 282         // Add the moodle group's module data.
 283         $this->YUI_config->add_moodle_metadata();
 284
 285         // Every page should include definition of following modules.
 286         $this->js_module($this->find_module('core_filepicker'));
 287         $this->js_module($this->find_module('core_comment'));
 288     }
 289
 290     /**
 291      * Return the safe config values that get set for javascript in "M.cfg".
 292      *
 293      * @since 2.9
 294      * @return array List of safe config values that are available to javascript.
 295      */
 296     public function get_config_for_javascript(moodle_page $page, renderer_base $renderer) {
 297         global $CFG;
 298
 299         if (empty($this->M_cfg)) {
 300
 301             $iconsystem = \core\output\icon_system::instance();
 302
 303             // It is possible that the $page->context is null, so we can't use $page->context->id.
 304             $contextid = null;
 305             $contextinstanceid = null;
 306             if (!is_null($page->context)) {
 307                 $contextid = $page->context->id;
 308                 $contextinstanceid = $page->context->instanceid;
 309                 $courseid = $page->course->id;
 310                 $coursecontext = context_course::instance($courseid);
 311             }
 312
 313             $this->M_cfg = array(
 314                 'wwwroot'               => $CFG->wwwroot,
 315                 'homeurl'               => $page->navigation->action,
 316                 'sesskey'               => sesskey(),
 317                 'sessiontimeout'        => $CFG->sessiontimeout,
 318                 'sessiontimeoutwarning' => $CFG->sessiontimeoutwarning,
 319                 'themerev'              => theme_get_revision(),
 320                 'slasharguments'        => (int)(!empty($CFG->slasharguments)),
 321                 'theme'                 => $page->theme->name,
 322                 'iconsystemmodule'      => $iconsystem->get_amd_name(),
 323                 'jsrev'                 => $this->get_jsrev(),
 324                 'admin'                 => $CFG->admin,
 325                 'svgicons'              => $page->theme->use_svg_icons(),
 326                 'usertimezone'          => usertimezone(),
 327                 'language'              => current_language(),
 328                 'courseId'              => isset($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'           => $this->get_templaterev(),
 334                 'siteId'                => (int) SITEID,
 335             );
 336             if ($CFG->debugdeveloper) {
 337                 $this->M_cfg['developerdebug'] = true;
 338             }
 339             if (defined('BEHAT_SITE_RUNNING')) {
 340                 $this->M_cfg['behatsiterunning'] = true;
 341             }
 342
 343         }
 344         return $this->M_cfg;
 345     }
 346
 347     /**
 348      * Initialise with the bits of JavaScript that every Moodle page should have.
 349      *
 350      * @param moodle_page $page
 351      * @param core_renderer $renderer
 352      */
 353     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 354         global $CFG;
 355
 356         // Init the js config.
 357         $this->get_config_for_javascript($page, $renderer);
 358
 359         // Accessibility stuff.
 360         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 361
 362         // Add strings used on many pages.
 363         $this->string_for_js('confirmation', 'admin');
 364         $this->string_for_js('cancel', 'moodle');
 365         $this->string_for_js('yes', 'moodle');
 366
 367         // Alter links in top frame to break out of frames.
 368         if ($page->pagelayout === 'frametop') {
 369             $this->js_init_call('M.util.init_frametop');
 370         }
 371
 372         // Include block drag/drop if editing is on
 373         if ($page->user_is_editing()) {
 374             $params = array(
 375                 'regions' => $page->blocks->get_regions(),
 376                 'pagehash' => $page->get_edited_page_hash(),
 377             );
 378             if (!empty($page->cm->id)) {
 379                 $params['cmid'] = $page->cm->id;
 380             }
 381             // Strings for drag and drop.
 382             $this->strings_for_js(array('movecontent',
 383                                         'tocontent',
 384                                         'emptydragdropregion'),
 385                                   'moodle');
 386             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 387             $page->requires->js_call_amd('core_block/edit', 'init', ['pagehash' => $page->get_edited_page_hash()]);
 388         }
 389
 390         // Include the YUI CSS Modules.
 391         $page->requires->set_yuicssmodules($page->theme->yuicssmodules);
 392     }
 393
 394     /**
 395      * Determine the correct JS Revision to use for this load.
 396      *
 397      * @return int the jsrev to use.
 398      */
 399     public function get_jsrev() {
 400         global $CFG;
 401
 402         if (empty($CFG->cachejs)) {
 403             $jsrev = -1;
 404         } else if (empty($CFG->jsrev)) {
 405             $jsrev = 1;
 406         } else {
 407             $jsrev = $CFG->jsrev;
 408         }
 409
 410         return $jsrev;
 411     }
 412
 413     /**
 414      * Determine the correct Template revision to use for this load.
 415      *
 416      * @return int the templaterev to use.
 417      */
 418     protected function get_templaterev() {
 419         global $CFG;
 420
 421         if (empty($CFG->cachetemplates)) {
 422             $templaterev = -1;
 423         } else if (empty($CFG->templaterev)) {
 424             $templaterev = 1;
 425         } else {
 426             $templaterev = $CFG->templaterev;
 427         }
 428
 429         return $templaterev;
 430     }
 431
 432     /**
 433      * Ensure that the specified JavaScript file is linked to from this page.
 434      *
 435      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 436      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 437      *
 438      * By default the link is put at the end of the page, since this gives best page-load performance.
 439      *
 440      * Even if a particular script is requested more than once, it will only be linked
 441      * to once.
 442      *
 443      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 444      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 445      * @param bool $inhead initialise in head
 446      */
 447     public function js($url, $inhead = false) {
 448         if ($url == '/question/qengine.js') {
 449             debugging('The question/qengine.js has been deprecated. ' .
 450                 'Please use core_question/question_engine', DEBUG_DEVELOPER);
 451         }
 452         $url = $this->js_fix_url($url);
 453         $where = $inhead ? 'head' : 'footer';
 454         $this->jsincludes[$where][$url->out()] = $url;
 455     }
 456
 457     /**
 458      * Request inclusion of jQuery library in the page.
 459      *
 460      * NOTE: this should not be used in official Moodle distribution!
 461      *
 462      * {@link https://moodledev.io/docs/guides/javascript/jquery}
 463      */
 464     public function jquery() {
 465         $this->jquery_plugin('jquery');
 466     }
 467
 468     /**
 469      * Request inclusion of jQuery plugin.
 470      *
 471      * NOTE: this should not be used in official Moodle distribution!
 472      *
 473      * jQuery plugins are located in plugin/jquery/* subdirectory,
 474      * plugin/jquery/plugins.php lists all available plugins.
 475      *
 476      * Included core plugins:
 477      *   - jQuery UI
 478      *
 479      * Add-ons may include extra jQuery plugins in jquery/ directory,
 480      * plugins.php file defines the mapping between plugin names and
 481      * necessary page includes.
 482      *
 483      * Examples:
 484      * <code>
 485      *   // file: mod/xxx/view.php
 486      *   $PAGE->requires->jquery();
 487      *   $PAGE->requires->jquery_plugin('ui');
 488      *   $PAGE->requires->jquery_plugin('ui-css');
 489      * </code>
 490      *
 491      * <code>
 492      *   // file: theme/yyy/lib.php
 493      *   function theme_yyy_page_init(moodle_page $page) {
 494      *       $page->requires->jquery();
 495      *       $page->requires->jquery_plugin('ui');
 496      *       $page->requires->jquery_plugin('ui-css');
 497      *   }
 498      * </code>
 499      *
 500      * <code>
 501      *   // file: blocks/zzz/block_zzz.php
 502      *   public function get_required_javascript() {
 503      *       parent::get_required_javascript();
 504      *       $this->page->requires->jquery();
 505      *       $page->requires->jquery_plugin('ui');
 506      *       $page->requires->jquery_plugin('ui-css');
 507      *   }
 508      * </code>
 509      *
 510      * {@link https://moodledev.io/docs/guides/javascript/jquery}
 511      *
 512      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 513      * @param string $component name of the component
 514      * @return bool success
 515      */
 516     public function jquery_plugin($plugin, $component = 'core') {
 517         global $CFG;
 518
 519         if ($this->headdone) {
 520             debugging('Can not add jQuery plugins after starting page output!');
 521             return false;
 522         }
 523
 524         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css'))) {
 525             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 526             $component = 'core';
 527         } else if ($component !== 'core' and strpos($component, '_') === false) {
 528             // Let's normalise the legacy activity names, Frankenstyle rulez!
 529             $component = 'mod_' . $component;
 530         }
 531
 532         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 533             // Make sure the jQuery itself is always loaded first,
 534             // the order of all other plugins depends on order of $PAGE_>requires->.
 535             $this->jquery_plugin('jquery', 'core');
 536         }
 537
 538         if (isset($this->jqueryplugins[$plugin])) {
 539             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 540             return true;
 541         }
 542
 543         $componentdir = core_component::get_component_directory($component);
 544         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 545             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 546             return false;
 547         }
 548
 549         $plugins = array();
 550         require("$componentdir/jquery/plugins.php");
 551
 552         if (!isset($plugins[$plugin])) {
 553             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 554             return false;
 555         }
 556
 557         $this->jqueryplugins[$plugin] = new stdClass();
 558         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 559         $this->jqueryplugins[$plugin]->component = $component;
 560         $this->jqueryplugins[$plugin]->urls      = array();
 561
 562         foreach ($plugins[$plugin]['files'] as $file) {
 563             if ($CFG->debugdeveloper) {
 564                 if (!file_exists("$componentdir/jquery/$file")) {
 565                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 566                     continue;
 567                 }
 568                 $file = str_replace('.min.css', '.css', $file);
 569                 $file = str_replace('.min.js', '.js', $file);
 570             }
 571             if (!file_exists("$componentdir/jquery/$file")) {
 572                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 573                 continue;
 574             }
 575             if (!empty($CFG->slasharguments)) {
 576                 $url = new moodle_url("/theme/jquery.php");
 577                 $url->set_slashargument("/$component/$file");
 578
 579             } else {
 580                 // This is not really good, we need slasharguments for relative links, this means no caching...
 581                 $path = realpath("$componentdir/jquery/$file");
 582                 if (strpos($path, $CFG->dirroot) === 0) {
 583                     $url = $CFG->wwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 584                     // Replace all occurences of backslashes characters in url to forward slashes.
 585                     $url = str_replace('\\', '/', $url);
 586                     $url = new moodle_url($url);
 587                 } else {
 588                     // Bad luck, fix your server!
 589                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 590                     continue;
 591                 }
 592             }
 593             $this->jqueryplugins[$plugin]->urls[] = $url;
 594         }
 595
 596         return true;
 597     }
 598
 599     /**
 600      * Request replacement of one jQuery plugin by another.
 601      *
 602      * This is useful when themes want to replace the jQuery UI theme,
 603      * the problem is that theme can not prevent others from including the core ui-css plugin.
 604      *
 605      * Example:
 606      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 607      *  2/ write theme/yourtheme/jquery/plugins.php
 608      *  3/ init jQuery from theme
 609      *
 610      * <code>
 611      *   // file theme/yourtheme/lib.php
 612      *   function theme_yourtheme_page_init($page) {
 613      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 614      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 615      *   }
 616      * </code>
 617      *
 618      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 619      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 620      *
 621      * {@link https://moodledev.io/docs/guides/javascript/jquery}
 622      *
 623      * @param string $oldplugin original plugin
 624      * @param string $newplugin the replacement
 625      */
 626     public function jquery_override_plugin($oldplugin, $newplugin) {
 627         if ($this->headdone) {
 628             debugging('Can not override jQuery plugins after starting page output!');
 629             return;
 630         }
 631         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 632     }
 633
 634     /**
 635      * Return jQuery related markup for page start.
 636      * @return string
 637      */
 638     protected function get_jquery_headcode() {
 639         if (empty($this->jqueryplugins['jquery'])) {
 640             // If nobody requested jQuery then do not bother to load anything.
 641             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 642             return '';
 643         }
 644
 645         $included = array();
 646         $urls = array();
 647
 648         foreach ($this->jqueryplugins as $name => $unused) {
 649             if (isset($included[$name])) {
 650                 continue;
 651             }
 652             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 653                 // The following loop tries to resolve the replacements,
 654                 // use max 100 iterations to prevent infinite loop resulting
 655                 // in blank page.
 656                 $cyclic = true;
 657                 $oldname = $name;
 658                 for ($i=0; $i<100; $i++) {
 659                     $name = $this->jquerypluginoverrides[$name];
 660                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 661                         $cyclic = false;
 662                         break;
 663                     }
 664                 }
 665                 if ($cyclic) {
 666                     // We can not do much with cyclic references here, let's use the old plugin.
 667                     $name = $oldname;
 668                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 669
 670                 } else if (empty($name)) {
 671                     // Developer requested removal of the plugin.
 672                     continue;
 673
 674                 } else if (!isset($this->jqueryplugins[$name])) {
 675                     debugging("Unknown jQuery override plugin '$name' detected");
 676                     $name = $oldname;
 677
 678                 } else if (isset($included[$name])) {
 679                     // The plugin was already included, easy.
 680                     continue;
 681                 }
 682             }
 683
 684             $plugin = $this->jqueryplugins[$name];
 685             $urls = array_merge($urls, $plugin->urls);
 686             $included[$name] = true;
 687         }
 688
 689         $output = '';
 690         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 691         foreach ($urls as $url) {
 692             if (preg_match('/\.js$/', $url)) {
 693                 $output .= html_writer::script('', $url);
 694             } else if (preg_match('/\.css$/', $url)) {
 695                 $attributes['href'] = $url;
 696                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 697             }
 698         }
 699
 700         return $output;
 701     }
 702
 703     /**
 704      * Returns the actual url through which a JavaScript file is served.
 705      *
 706      * @param moodle_url|string $url full moodle url, or shortened path to script.
 707      * @throws coding_exception if the given $url isn't a shortened url starting with / or a moodle_url instance.
 708      * @return moodle_url
 709      */
 710     protected function js_fix_url($url) {
 711         global $CFG;
 712
 713         if ($url instanceof moodle_url) {
 714             // If the URL is external to Moodle, it won't be handled by Moodle (!).
 715             if ($url->is_local_url()) {
 716                 $localurl = $url->out_as_local_url();
 717                 // Check if the URL points to a Moodle PHP resource.
 718                 if (strpos($localurl, '.php') !== false) {
 719                     // It's a Moodle PHP resource e.g. a resource already served by the proper Moodle Handler.
 720                     return $url;
 721                 }
 722                 // It's a local resource: we need to further examine it.
 723                 return $this->js_fix_url($url->out_as_local_url(false));
 724             }
 725             // The URL is not a Moodle resource.
 726             return $url;
 727         } else if (null !== $url && strpos($url, '/') === 0) {
 728             // Fix the admin links if needed.
 729             if ($CFG->admin !== 'admin') {
 730                 if (strpos($url, "/admin/") === 0) {
 731                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 732                 }
 733             }
 734             if (debugging()) {
 735                 // Check file existence only when in debug mode.
 736                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 737                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 738                 }
 739             }
 740             if (substr($url, -3) === '.js') {
 741                 $jsrev = $this->get_jsrev();
 742                 if (empty($CFG->slasharguments)) {
 743                     return new moodle_url('/lib/javascript.php', ['rev' => $jsrev, 'jsfile' => $url]);
 744                 } else {
 745                     $returnurl = new moodle_url('/lib/javascript.php');
 746                     $returnurl->set_slashargument('/'.$jsrev.$url);
 747                     return $returnurl;
 748                 }
 749             } else {
 750                 return new moodle_url($url);
 751             }
 752         } else {
 753             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 754         }
 755     }
 756
 757     /**
 758      * Find out if JS module present and return details.
 759      *
 760      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 761      * @return array description of module or null if not found
 762      */
 763     protected function find_module($component) {
 764         global $CFG, $PAGE;
 765
 766         $module = null;
 767
 768         if (strpos($component, 'core_') === 0) {
 769             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 770             // so that we do nto have to repeat the definition of these modules over and over again.
 771             switch($component) {
 772                 case 'core_filepicker':
 773                     $module = array('name'     => 'core_filepicker',
 774                                     'fullpath' => '/repository/filepicker.js',
 775                                     'requires' => array(
 776                                         'base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form',
 777                                         'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin',
 778                                         'escape', 'moodle-core_filepicker', 'moodle-core-notification-dialogue'
 779                                     ),
 780                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 781                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 782                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 783                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 784                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 785                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 786                                                         array('referencesexist', 'repository'), array('select', 'repository')
 787                                                     ));
 788                     break;
 789                 case 'core_comment':
 790                     $module = array('name'     => 'core_comment',
 791                                     'fullpath' => '/comment/comment.js',
 792                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay', 'escape'),
 793                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 794                                 );
 795                     break;
 796                 case 'core_role':
 797                     $module = array('name'     => 'core_role',
 798                                     'fullpath' => '/admin/roles/module.js',
 799                                     'requires' => array('node', 'cookie'));
 800                     break;
 801                 case 'core_completion':
 802                     break;
 803                 case 'core_message':
 804                     $module = array('name'     => 'core_message',
 805                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 806                                     'fullpath' => '/message/module.js');
 807                     break;
 808                 case 'core_group':
 809                     $module = array('name'     => 'core_group',
 810                                     'fullpath' => '/group/module.js',
 811                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 812                     break;
 813                 case 'core_question_engine':
 814                     $module = array('name'     => 'core_question_engine',
 815                                     'fullpath' => '/question/qengine.js',
 816                                     'requires' => array('node', 'event'));
 817                     break;
 818                 case 'core_rating':
 819                     $module = array('name'     => 'core_rating',
 820                                     'fullpath' => '/rating/module.js',
 821                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 822                     break;
 823                 case 'core_dndupload':
 824                     $module = array('name'     => 'core_dndupload',
 825                                     'fullpath' => '/lib/form/dndupload.js',
 826                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 827                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 828                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesfile', 'error'),
 829                                                         array('sizegb', 'moodle'), array('sizemb', 'moodle'), array('sizekb', 'moodle'), array('sizeb', 'moodle'),
 830                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 831                                                         array('changesmadereallygoaway', 'moodle'), array('complete', 'moodle')
 832                                                     ));
 833                     break;
 834             }
 835
 836         } else {
 837             if ($dir = core_component::get_component_directory($component)) {
 838                 if (file_exists("$dir/module.js")) {
 839                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 840                         $dir = substr($dir, strlen($CFG->dirroot));
 841                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 842                     }
 843                 }
 844             }
 845         }
 846
 847         return $module;
 848     }
 849
 850     /**
 851      * Append YUI3 module to default YUI3 JS loader.
 852      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 853      *
 854      * @param string|array $module name of module (details are autodetected), or full module specification as array
 855      * @return void
 856      */
 857     public function js_module($module) {
 858         global $CFG;
 859
 860         if (empty($module)) {
 861             throw new coding_exception('Missing YUI3 module name or full description.');
 862         }
 863
 864         if (is_string($module)) {
 865             $module = $this->find_module($module);
 866         }
 867
 868         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 869             throw new coding_exception('Missing YUI3 module details.');
 870         }
 871
 872         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 873         // Add all needed strings.
 874         if (!empty($module['strings'])) {
 875             foreach ($module['strings'] as $string) {
 876                 $identifier = $string[0];
 877                 $component = isset($string[1]) ? $string[1] : 'moodle';
 878                 $a = isset($string[2]) ? $string[2] : null;
 879                 $this->string_for_js($identifier, $component, $a);
 880             }
 881         }
 882         unset($module['strings']);
 883
 884         // Process module requirements and attempt to load each. This allows
 885         // moodle modules to require each other.
 886         if (!empty($module['requires'])){
 887             foreach ($module['requires'] as $requirement) {
 888                 $rmodule = $this->find_module($requirement);
 889                 if (is_array($rmodule)) {
 890                     $this->js_module($rmodule);
 891                 }
 892             }
 893         }
 894
 895         if ($this->headdone) {
 896             $this->extramodules[$module['name']] = $module;
 897         } else {
 898             $this->YUI_config->add_module_config($module['name'], $module);
 899         }
 900     }
 901
 902     /**
 903      * Returns true if the module has already been loaded.
 904      *
 905      * @param string|array $module
 906      * @return bool True if the module has already been loaded
 907      */
 908     protected function js_module_loaded($module) {
 909         if (is_string($module)) {
 910             $modulename = $module;
 911         } else {
 912             $modulename = $module['name'];
 913         }
 914         return array_key_exists($modulename, $this->YUI_config->modules) ||
 915                array_key_exists($modulename, $this->extramodules);
 916     }
 917
 918     /**
 919      * Ensure that the specified CSS file is linked to from this page.
 920      *
 921      * Because stylesheet links must go in the <head> part of the HTML, you must call
 922      * this function before {@link get_head_code()} is called. That normally means before
 923      * the call to print_header. If you call it when it is too late, an exception
 924      * will be thrown.
 925      *
 926      * Even if a particular style sheet is requested more than once, it will only
 927      * be linked to once.
 928      *
 929      * Please note use of this feature is strongly discouraged,
 930      * it is suitable only for places where CSS is submitted directly by teachers.
 931      * (Students must not be allowed to submit any external CSS because it may
 932      * contain embedded javascript!). Example of correct use is mod/data.
 933      *
 934      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 935      *   For example:
 936      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 937      */
 938     public function css($stylesheet) {
 939         global $CFG;
 940
 941         if ($this->headdone) {
 942             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 943         }
 944
 945         if ($stylesheet instanceof moodle_url) {
 946             // ok
 947         } else if (strpos($stylesheet, '/') === 0) {
 948             $stylesheet = new moodle_url($stylesheet);
 949         } else {
 950             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 951         }
 952
 953         $this->cssurls[$stylesheet->out()] = $stylesheet;
 954     }
 955
 956     /**
 957      * Add theme stylesheet to page - do not use from plugin code,
 958      * this should be called only from the core renderer!
 959      *
 960      * @param moodle_url $stylesheet
 961      * @return void
 962      */
 963     public function css_theme(moodle_url $stylesheet) {
 964         $this->cssthemeurls[] = $stylesheet;
 965     }
 966
 967     /**
 968      * Ensure that a skip link to a given target is printed at the top of the <body>.
 969      *
 970      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 971      * will be thrown). That normally means you must call this before the call to print_header.
 972      *
 973      * If you ask for a particular skip link to be printed, it is then your responsibility
 974      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 975      * page, so that the skip link goes somewhere.
 976      *
 977      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 978      *
 979      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 980      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 981      */
 982     public function skip_link_to($target, $linktext) {
 983         if ($this->topofbodydone) {
 984             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 985             return;
 986         }
 987         $this->skiplinks[$target] = $linktext;
 988     }
 989
 990     /**
 991      * !!!DEPRECATED!!! please use js_init_call() if possible
 992      * Ensure that the specified JavaScript function is called from an inline script
 993      * somewhere on this page.
 994      *
 995      * By default the call will be put in a script tag at the
 996      * end of the page after initialising Y instance, since this gives best page-load
 997      * performance and allows you to use YUI3 library.
 998      *
 999      * If you request that a particular function is called several times, then
1000      * that is what will happen (unlike linking to a CSS or JS file, where only
1001      * one link will be output).
1002      *
1003      * The main benefit of the method is the automatic encoding of all function parameters.
1004      *
1005      * @deprecated
1006      *
1007      * @param string $function the name of the JavaScritp function to call. Can
1008      *      be a compound name like 'Y.Event.purgeElement'. Can also be
1009      *      used to create and object by using a 'function name' like 'new user_selector'.
1010      * @param array $arguments and array of arguments to be passed to the function.
1011      *      When generating the function call, this will be escaped using json_encode,
1012      *      so passing objects and arrays should work.
1013      * @param bool $ondomready If tru the function is only called when the dom is
1014      *      ready for manipulation.
1015      * @param int $delay The delay before the function is called.
1016      */
1017     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
1018         $where = $ondomready ? 'ondomready' : 'normal';
1019         $this->jscalls[$where][] = array($function, $arguments, $delay);
1020     }
1021
1022     /**
1023      * This function appends a block of code to the AMD specific javascript block executed
1024      * in the page footer, just after loading the requirejs library.
1025      *
1026      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
1027      *
1028      * @param string $code The JS code to append.
1029      */
1030     public function js_amd_inline($code) {
1031         $this->amdjscode[] = $code;
1032     }
1033
1034     /**
1035      * Load an AMD module and eventually call its method.
1036      *
1037      * This function creates a minimal inline JS snippet that requires an AMD module and eventually calls a single
1038      * function from the module with given arguments. If it is called multiple times, it will be create multiple
1039      * snippets.
1040      *
1041      * @param string $fullmodule The name of the AMD module to load, formatted as <component name>/<module name>.
1042      * @param string $func Optional function from the module to call, defaults to just loading the AMD module.
1043      * @param array $params The params to pass to the function (will be serialized into JSON).
1044      */
1045     public function js_call_amd($fullmodule, $func = null, $params = array()) {
1046         global $CFG;
1047
1048         $modulepath = explode('/', $fullmodule);
1049
1050         $modname = clean_param(array_shift($modulepath), PARAM_COMPONENT);
1051         foreach ($modulepath as $module) {
1052             $modname .= '/' . clean_param($module, PARAM_ALPHANUMEXT);
1053         }
1054
1055         $functioncode = [];
1056         if ($func !== null) {
1057             $func = clean_param($func, PARAM_ALPHANUMEXT);
1058
1059             $jsonparams = array();
1060             foreach ($params as $param) {
1061                 $jsonparams[] = json_encode($param);
1062             }
1063             $strparams = implode(', ', $jsonparams);
1064             if ($CFG->debugdeveloper) {
1065                 $toomanyparamslimit = 1024;
1066                 if (strlen($strparams) > $toomanyparamslimit) {
1067                     debugging('Too much data passed as arguments to js_call_amd("' . $fullmodule . '", "' . $func .
1068                         '"). Generally there are better ways to pass lots of data from PHP to JavaScript, for example via Ajax, ' .
1069                         'data attributes, ... . This warning is triggered if the argument string becomes longer than ' .
1070                         $toomanyparamslimit . ' characters.', DEBUG_DEVELOPER);
1071                 }
1072             }
1073
1074             $functioncode[] = "amd.{$func}({$strparams});";
1075         }
1076
1077         $functioncode[] = "M.util.js_complete('{$modname}');";
1078
1079         $initcode = implode(' ', $functioncode);
1080         $js = "M.util.js_pending('{$modname}'); require(['{$modname}'], function(amd) {{$initcode}});";
1081
1082         $this->js_amd_inline($js);
1083     }
1084
1085     /**
1086      * Creates a JavaScript function call that requires one or more modules to be loaded.
1087      *
1088      * This function can be used to include all of the standard YUI module types within JavaScript:
1089      *     - YUI3 modules    [node, event, io]
1090      *     - YUI2 modules    [yui2-*]
1091      *     - Moodle modules  [moodle-*]
1092      *     - Gallery modules [gallery-*]
1093      *
1094      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1095      * @see js_call_amd()
1096      *
1097      * @param array|string $modules One or more modules
1098      * @param string $function The function to call once modules have been loaded
1099      * @param array $arguments An array of arguments to pass to the function
1100      * @param string $galleryversion Deprecated: The gallery version to use
1101      * @param bool $ondomready
1102      */
1103     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1104         if (!is_array($modules)) {
1105             $modules = array($modules);
1106         }
1107
1108         if ($galleryversion != null) {
1109             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1110         }
1111
1112         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1113         if ($ondomready) {
1114             $jscode = "Y.on('domready', function() { $jscode });";
1115         }
1116         $this->jsinitcode[] = $jscode;
1117     }
1118
1119     /**
1120      * Set the CSS Modules to be included from YUI.
1121      *
1122      * @param array $modules The list of YUI CSS Modules to include.
1123      */
1124     public function set_yuicssmodules(array $modules = array()) {
1125         $this->yuicssmodules = $modules;
1126     }
1127
1128     /**
1129      * Ensure that the specified JavaScript function is called from an inline script
1130      * from page footer.
1131      *
1132      * @param string $function the name of the JavaScritp function to with init code,
1133      *      usually something like 'M.mod_mymodule.init'
1134      * @param array $extraarguments and array of arguments to be passed to the function.
1135      *      The first argument is always the YUI3 Y instance with all required dependencies
1136      *      already loaded.
1137      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1138      * @param array $module JS module specification array
1139      */
1140     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1141         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1142         if (!$module) {
1143             // Detect module automatically.
1144             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1145                 $module = $this->find_module($matches[1]);
1146             }
1147         }
1148
1149         $this->js_init_code($jscode, $ondomready, $module);
1150     }
1151
1152     /**
1153      * Add short static javascript code fragment to page footer.
1154      * This is intended primarily for loading of js modules and initialising page layout.
1155      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1156      * may override it.
1157      *
1158      * @param string $jscode
1159      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1160      * @param array $module JS module specification array
1161      */
1162     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1163         $jscode = trim($jscode, " ;\n"). ';';
1164
1165         $uniqid = html_writer::random_id();
1166         $startjs = " M.util.js_pending('" . $uniqid . "');";
1167         $endjs = " M.util.js_complete('" . $uniqid . "');";
1168
1169         if ($module) {
1170             $this->js_module($module);
1171             $modulename = $module['name'];
1172             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1173         }
1174
1175         if ($ondomready) {
1176             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1177         }
1178
1179         $this->jsinitcode[] = $jscode;
1180     }
1181
1182     /**
1183      * Make a language string available to JavaScript.
1184      *
1185      * All the strings will be available in a M.str object in the global namespace.
1186      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1187      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1188      * equivalent in the current language.
1189      *
1190      * The arguments to this function are just like the arguments to get_string
1191      * except that $component is not optional, and there are some aspects to consider
1192      * when the string contains {$a} placeholder.
1193      *
1194      * If the string does not contain any {$a} placeholder, you can simply use
1195      * M.str.component.identifier to obtain it. If you prefer, you can call
1196      * M.util.get_string(identifier, component) to get the same result.
1197      *
1198      * If you need to use {$a} placeholders, there are two options. Either the
1199      * placeholder should be substituted in PHP on server side or it should
1200      * be substituted in Javascript at client side.
1201      *
1202      * To substitute the placeholder at server side, just provide the required
1203      * value for the placeholder when you require the string. Because each string
1204      * is only stored once in the JavaScript (based on $identifier and $module)
1205      * you cannot get the same string with two different values of $a. If you try,
1206      * an exception will be thrown. Once the placeholder is substituted, you can
1207      * use M.str or M.util.get_string() as shown above:
1208      *
1209      *     // Require the string in PHP and replace the placeholder.
1210      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1211      *     // Use the result of the substitution in Javascript.
1212      *     alert(M.str.moodle.fullnamedisplay);
1213      *
1214      * To substitute the placeholder at client side, use M.util.get_string()
1215      * function. It implements the same logic as {@link get_string()}:
1216      *
1217      *     // Require the string in PHP but keep {$a} as it is.
1218      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1219      *     // Provide the values on the fly in Javascript.
1220      *     user = { firstname : 'Harry', lastname : 'Potter' }
1221      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1222      *
1223      * If you do need the same string expanded with different $a values in PHP
1224      * on server side, then the solution is to put them in your own data structure
1225      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1226      *
1227      * @param string $identifier the desired string.
1228      * @param string $component the language file to look in.
1229      * @param mixed $a any extra data to add into the string (optional).
1230      */
1231     public function string_for_js($identifier, $component, $a = null) {
1232         if (!$component) {
1233             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1234         }
1235         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1236             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1237                     "from lang file '$component' with different \$a parameter?");
1238         }
1239         if (!isset($this->stringsforjs[$component][$identifier])) {
1240             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1241             $this->stringsforjs_as[$component][$identifier] = $a;
1242         }
1243     }
1244
1245     /**
1246      * Make an array of language strings available for JS.
1247      *
1248      * This function calls the above function {@link string_for_js()} for each requested
1249      * string in the $identifiers array that is passed to the argument for a single module
1250      * passed in $module.
1251      *
1252      * <code>
1253      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1254      *
1255      * // The above is identical to calling:
1256      *
1257      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1258      * $PAGE->requires->string_for_js('two', 'mymod');
1259      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1260      * </code>
1261      *
1262      * @param array $identifiers An array of desired strings
1263      * @param string $component The module to load for
1264      * @param mixed $a This can either be a single variable that gets passed as extra
1265      *         information for every string or it can be an array of mixed data where the
1266      *         key for the data matches that of the identifier it is meant for.
1267      *
1268      */
1269     public function strings_for_js($identifiers, $component, $a = null) {
1270         foreach ($identifiers as $key => $identifier) {
1271             if (is_array($a) && array_key_exists($key, $a)) {
1272                 $extra = $a[$key];
1273             } else {
1274                 $extra = $a;
1275             }
1276             $this->string_for_js($identifier, $component, $extra);
1277         }
1278     }
1279
1280     /**
1281      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1282      *
1283      * Make some data from PHP available to JavaScript code.
1284      *
1285      * For example, if you call
1286      * <pre>
1287      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1288      * </pre>
1289      * then in JavsScript mydata.name will be 'Moodle'.
1290      *
1291      * @deprecated
1292      * @param string $variable the the name of the JavaScript variable to assign the data to.
1293      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1294      *      should be considered an experimental feature.
1295      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1296      *      so passing objects and arrays should work.
1297      * @param bool $inhead initialise in head
1298      * @return void
1299      */
1300     public function data_for_js($variable, $data, $inhead=false) {
1301         $where = $inhead ? 'head' : 'footer';
1302         $this->jsinitvariables[$where][] = array($variable, $data);
1303     }
1304
1305     /**
1306      * Creates a YUI event handler.
1307      *
1308      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1309      * @param string $event A valid DOM event (click, mousedown, change etc.)
1310      * @param string $function The name of the function to call
1311      * @param array  $arguments An optional array of argument parameters to pass to the function
1312      */
1313     public function event_handler($selector, $event, $function, array $arguments = null) {
1314         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1315     }
1316
1317     /**
1318      * Returns code needed for registering of event handlers.
1319      * @return string JS code
1320      */
1321     protected function get_event_handler_code() {
1322         $output = '';
1323         foreach ($this->eventhandlers as $h) {
1324             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1325         }
1326         return $output;
1327     }
1328
1329     /**
1330      * Get the inline JavaScript code that need to appear in a particular place.
1331      * @param bool $ondomready
1332      * @return string
1333      */
1334     protected function get_javascript_code($ondomready) {
1335         $where = $ondomready ? 'ondomready' : 'normal';
1336         $output = '';
1337         if ($this->jscalls[$where]) {
1338             foreach ($this->jscalls[$where] as $data) {
1339                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1340             }
1341             if (!empty($ondomready)) {
1342                 $output = "    Y.on('domready', function() {\n$output\n});";
1343             }
1344         }
1345         return $output;
1346     }
1347
1348     /**
1349      * Returns js code to be executed when Y is available.
1350      * @return string
1351      */
1352     protected function get_javascript_init_code() {
1353         if (count($this->jsinitcode)) {
1354             return implode("\n", $this->jsinitcode) . "\n";
1355         }
1356         return '';
1357     }
1358
1359     /**
1360      * Returns js code to load amd module loader, then insert inline script tags
1361      * that contain require() calls using RequireJS.
1362      * @return string
1363      */
1364     protected function get_amd_footercode() {
1365         global $CFG;
1366         $output = '';
1367
1368         // We will cache JS if cachejs is not set, or it is true.
1369         $cachejs = !isset($CFG->cachejs) || $CFG->cachejs;
1370         $jsrev = $this->get_jsrev();
1371
1372         $jsloader = new moodle_url('/lib/javascript.php');
1373         $jsloader->set_slashargument('/' . $jsrev . '/');
1374         $requirejsloader = new moodle_url('/lib/requirejs.php');
1375         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1376
1377         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1378
1379         // No extension required unless slash args is disabled.
1380         $jsextension = '.js';
1381         if (!empty($CFG->slasharguments)) {
1382             $jsextension = '';
1383         }
1384
1385         $minextension = '.min';
1386         if (!$cachejs) {
1387             $minextension = '';
1388         }
1389
1390         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1391         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1392         $requirejsconfig = str_replace('[JSMIN]', $minextension, $requirejsconfig);
1393         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1394
1395         $output .= html_writer::script($requirejsconfig);
1396         if ($cachejs) {
1397             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1398         } else {
1399             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1400         }
1401
1402         // First include must be to a module with no dependencies, this prevents multiple requests.
1403         $prefix = <<<EOF
1404 M.util.js_pending("core/first");
1405 require(['core/first'], function() {
1406
1407 EOF;
1408
1409         if (during_initial_install()) {
1410             // Do not run a prefetch during initial install as the DB is not available to service WS calls.
1411             $prefetch = '';
1412         } else {
1413             $prefetch = "require(['core/prefetch'])\n";
1414         }
1415
1416         $suffix = <<<EOF
1417
1418     M.util.js_complete("core/first");
1419 });
1420 EOF;
1421
1422         $output .= html_writer::script($prefix . $prefetch . implode(";\n", $this->amdjscode) . $suffix);
1423         return $output;
1424     }
1425
1426     /**
1427      * Returns basic YUI3 CSS code.
1428      *
1429      * @return string
1430      */
1431     protected function get_yui3lib_headcss() {
1432         global $CFG;
1433
1434         $yuiformat = '-min';
1435         if ($this->yui3loader->filter === 'RAW') {
1436             $yuiformat = '';
1437         }
1438
1439         $code = '';
1440         if ($this->yui3loader->combine) {
1441             if (!empty($this->yuicssmodules)) {
1442                 $modules = array();
1443                 foreach ($this->yuicssmodules as $module) {
1444                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1445                 }
1446                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1447             }
1448             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1449
1450         } else {
1451             if (!empty($this->yuicssmodules)) {
1452                 foreach ($this->yuicssmodules as $module) {
1453                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1454                 }
1455             }
1456             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1457         }
1458
1459         if ($this->yui3loader->filter === 'RAW') {
1460             $code = str_replace('-min.css', '.css', $code);
1461         } else if ($this->yui3loader->filter === 'DEBUG') {
1462             $code = str_replace('-min.css', '.css', $code);
1463         }
1464         return $code;
1465     }
1466
1467     /**
1468      * Returns basic YUI3 JS loading code.
1469      *
1470      * @return string
1471      */
1472     protected function get_yui3lib_headcode() {
1473         global $CFG;
1474
1475         $jsrev = $this->get_jsrev();
1476
1477         $yuiformat = '-min';
1478         if ($this->yui3loader->filter === 'RAW') {
1479             $yuiformat = '';
1480         }
1481
1482         $format = '-min';
1483         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1484             $format = '-debug';
1485         }
1486
1487         $rollupversion = $CFG->yui3version;
1488         if (!empty($CFG->yuipatchlevel)) {
1489             $rollupversion .= '_' . $CFG->yuipatchlevel;
1490         }
1491
1492         $baserollups = array(
1493             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1494         );
1495
1496         if ($this->yui3loader->combine) {
1497             return '<script src="' .
1498                     $this->yui3loader->local_comboBase .
1499                     implode('&amp;', $baserollups) .
1500                     '"></script>';
1501         } else {
1502             $code = '';
1503             foreach ($baserollups as $rollup) {
1504                 $code .= '<script src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1505             }
1506             return $code;
1507         }
1508
1509     }
1510
1511     /**
1512      * Returns html tags needed for inclusion of theme CSS.
1513      *
1514      * @return string
1515      */
1516     protected function get_css_code() {
1517         // First of all the theme CSS, then any custom CSS
1518         // Please note custom CSS is strongly discouraged,
1519         // because it can not be overridden by themes!
1520         // It is suitable only for things like mod/data which accepts CSS from teachers.
1521         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1522
1523         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1524         $code = $this->get_yui3lib_headcss();
1525
1526         // This line of code may look funny but it is currently required in order
1527         // to avoid MASSIVE display issues in Internet Explorer.
1528         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1529         // ignored whenever another resource is added until such time as a redraw
1530         // is forced, usually by moving the mouse over the affected element.
1531         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1532
1533         $urls = $this->cssthemeurls + $this->cssurls;
1534         foreach ($urls as $url) {
1535             $attributes['href'] = $url;
1536             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1537             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1538             unset($attributes['id']);
1539         }
1540
1541         return $code;
1542     }
1543
1544     /**
1545      * Adds extra modules specified after printing of page header.
1546      *
1547      * @return string
1548      */
1549     protected function get_extra_modules_code() {
1550         if (empty($this->extramodules)) {
1551             return '';
1552         }
1553         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1554     }
1555
1556     /**
1557      * Generate any HTML that needs to go inside the <head> tag.
1558      *
1559      * Normally, this method is called automatically by the code that prints the
1560      * <head> tag. You should not normally need to call it in your own code.
1561      *
1562      * @param moodle_page $page
1563      * @param core_renderer $renderer
1564      * @return string the HTML code to to inside the <head> tag.
1565      */
1566     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1567         global $CFG;
1568
1569         // Note: the $page and $output are not stored here because it would
1570         // create circular references in memory which prevents garbage collection.
1571         $this->init_requirements_data($page, $renderer);
1572
1573         $output = '';
1574
1575         // Add all standard CSS for this page.
1576         $output .= $this->get_css_code();
1577
1578         // Set up the M namespace.
1579         $js = "var M = {}; M.yui = {};\n";
1580
1581         // Capture the time now ASAP during page load. This minimises the lag when
1582         // we try to relate times on the server to times in the browser.
1583         // An example of where this is used is the quiz countdown timer.
1584         $js .= "M.pageloadstarttime = new Date();\n";
1585
1586         // Add a subset of Moodle configuration to the M namespace.
1587         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1588
1589         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1590         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1591         //       this needs to be done before including any other script.
1592         $js .= $this->YUI_config->get_config_functions();
1593         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1594         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1595         $js = $this->YUI_config->update_header_js($js);
1596
1597         $output .= html_writer::script($js);
1598
1599         // Add variables.
1600         if ($this->jsinitvariables['head']) {
1601             $js = '';
1602             foreach ($this->jsinitvariables['head'] as $data) {
1603                 list($var, $value) = $data;
1604                 $js .= js_writer::set_variable($var, $value, true);
1605             }
1606             $output .= html_writer::script($js);
1607         }
1608
1609         // Mark head sending done, it is not possible to anything there.
1610         $this->headdone = true;
1611
1612         return $output;
1613     }
1614
1615     /**
1616      * Generate any HTML that needs to go at the start of the <body> tag.
1617      *
1618      * Normally, this method is called automatically by the code that prints the
1619      * <head> tag. You should not normally need to call it in your own code.
1620      *
1621      * @param renderer_base $renderer
1622      * @return string the HTML code to go at the start of the <body> tag.
1623      */
1624     public function get_top_of_body_code(renderer_base $renderer) {
1625         global $CFG;
1626
1627         // First the skip links.
1628         $output = $renderer->render_skip_links($this->skiplinks);
1629
1630         // Include the Polyfills.
1631         $output .= html_writer::script('', $this->js_fix_url('/lib/polyfills/polyfill.js'));
1632
1633         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1634         $output .= $this->get_yui3lib_headcode();
1635
1636         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1637         $output .= $this->get_jquery_headcode();
1638
1639         // Link our main JS file, all core stuff should be there.
1640         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1641
1642         // All the other linked things from HEAD - there should be as few as possible.
1643         if ($this->jsincludes['head']) {
1644             foreach ($this->jsincludes['head'] as $url) {
1645                 $output .= html_writer::script('', $url);
1646             }
1647         }
1648
1649         // Then the clever trick for hiding of things not needed when JS works.
1650         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1651         $this->topofbodydone = true;
1652         return $output;
1653     }
1654
1655     /**
1656      * Generate any HTML that needs to go at the end of the page.
1657      *
1658      * Normally, this method is called automatically by the code that prints the
1659      * page footer. You should not normally need to call it in your own code.
1660      *
1661      * @return string the HTML code to to at the end of the page.
1662      */
1663     public function get_end_code() {
1664         global $CFG;
1665         $output = '';
1666
1667         // Set the log level for the JS logging.
1668         $logconfig = new stdClass();
1669         $logconfig->level = 'warn';
1670         if ($CFG->debugdeveloper) {
1671             $logconfig->level = 'trace';
1672         }
1673         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1674         // Add any global JS that needs to run on all pages.
1675         $this->js_call_amd('core/page_global', 'init');
1676         $this->js_call_amd('core/utility');
1677
1678         // Call amd init functions.
1679         $output .= $this->get_amd_footercode();
1680
1681         // Add other requested modules.
1682         $output .= $this->get_extra_modules_code();
1683
1684         $this->js_init_code('M.util.js_complete("init");', true);
1685
1686         // All the other linked scripts - there should be as few as possible.
1687         if ($this->jsincludes['footer']) {
1688             foreach ($this->jsincludes['footer'] as $url) {
1689                 $output .= html_writer::script('', $url);
1690             }
1691         }
1692
1693         // Add all needed strings.
1694         // First add core strings required for some dialogues.
1695         $this->strings_for_js(array(
1696             'confirm',
1697             'yes',
1698             'no',
1699             'areyousure',
1700             'closebuttontitle',
1701             'unknownerror',
1702             'error',
1703             'file',
1704             'url',
1705             // TODO MDL-70830 shortforms should preload the collapseall/expandall strings properly.
1706             'collapseall',
1707             'expandall',
1708         ), 'moodle');
1709         $this->strings_for_js(array(
1710             'debuginfo',
1711             'line',
1712             'stacktrace',
1713         ), 'debug');
1714         $this->string_for_js('labelsep', 'langconfig');
1715         if (!empty($this->stringsforjs)) {
1716             $strings = array();
1717             foreach ($this->stringsforjs as $component=>$v) {
1718                 foreach($v as $indentifier => $langstring) {
1719                     $strings[$component][$indentifier] = $langstring->out();
1720                 }
1721             }
1722             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1723         }
1724
1725         // Add variables.
1726         if ($this->jsinitvariables['footer']) {
1727             $js = '';
1728             foreach ($this->jsinitvariables['footer'] as $data) {
1729                 list($var, $value) = $data;
1730                 $js .= js_writer::set_variable($var, $value, true);
1731             }
1732             $output .= html_writer::script($js);
1733         }
1734
1735         $inyuijs = $this->get_javascript_code(false);
1736         $ondomreadyjs = $this->get_javascript_code(true);
1737         $jsinit = $this->get_javascript_init_code();
1738         $handlersjs = $this->get_event_handler_code();
1739
1740         // There is a global Y, make sure it is available in your scope.
1741         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1742
1743         $output .= html_writer::script($js);
1744
1745         return $output;
1746     }
1747
1748     /**
1749      * Have we already output the code in the <head> tag?
1750      *
1751      * @return bool
1752      */
1753     public function is_head_done() {
1754         return $this->headdone;
1755     }
1756
1757     /**
1758      * Have we already output the code at the start of the <body> tag?
1759      *
1760      * @return bool
1761      */
1762     public function is_top_of_body_done() {
1763         return $this->topofbodydone;
1764     }
1765
1766     /**
1767      * Should we generate a bit of content HTML that is only required once  on
1768      * this page (e.g. the contents of the modchooser), now? Basically, we call
1769      * {@link has_one_time_item_been_created()}, and if the thing has not already
1770      * been output, we return true to tell the caller to generate it, and also
1771      * call {@link set_one_time_item_created()} to record the fact that it is
1772      * about to be generated.
1773      *
1774      * That is, a typical usage pattern (in a renderer method) is:
1775      * <pre>
1776      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1777      *     return '';
1778      * }
1779      * // Else generate it.
1780      * </pre>
1781      *
1782      * @param string $thing identifier for the bit of content. Should be of the form
1783      *      frankenstyle_things, e.g. core_course_modchooser.
1784      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1785      */
1786     public function should_create_one_time_item_now($thing) {
1787         if ($this->has_one_time_item_been_created($thing)) {
1788             return false;
1789         }
1790
1791         $this->set_one_time_item_created($thing);
1792         return true;
1793     }
1794
1795     /**
1796      * Has a particular bit of HTML that is only required once  on this page
1797      * (e.g. the contents of the modchooser) already been generated?
1798      *
1799      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1800      * method rather than calling this method directly.
1801      *
1802      * @param string $thing identifier for the bit of content. Should be of the form
1803      *      frankenstyle_things, e.g. core_course_modchooser.
1804      * @return bool whether that bit of output has been created.
1805      */
1806     public function has_one_time_item_been_created($thing) {
1807         return isset($this->onetimeitemsoutput[$thing]);
1808     }
1809
1810     /**
1811      * Indicate that a particular bit of HTML that is only required once on this
1812      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1813      *
1814      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1815      * method rather than calling this method directly.
1816      *
1817      * @param string $thing identifier for the bit of content. Should be of the form
1818      *      frankenstyle_things, e.g. core_course_modchooser.
1819      */
1820     public function set_one_time_item_created($thing) {
1821         if ($this->has_one_time_item_been_created($thing)) {
1822             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1823                     'once per page, but it seems to be being output again.');
1824         }
1825         return $this->onetimeitemsoutput[$thing] = true;
1826     }
1827 }
1828
1829 /**
1830  * This class represents the YUI configuration.
1831  *
1832  * @copyright 2013 Andrew Nicols
1833  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1834  * @since Moodle 2.5
1835  * @package core
1836  * @category output
1837  */
1838 class YUI_config {
1839     /**
1840      * These settings must be public so that when the object is converted to json they are exposed.
1841      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1842      *
1843      * The settings are described and documented in the YUI API at:
1844      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1845      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1846      */
1847     public $debug = false;
1848     public $base;
1849     public $comboBase;
1850     public $combine;
1851     public $filter = null;
1852     public $insertBefore = 'firstthemesheet';
1853     public $groups = array();
1854     public $modules = array();
1855     /** @var array The log sources that should be not be logged. */
1856     public $logInclude = [];
1857     /** @var array Tog sources that should be logged. */
1858     public $logExclude = [];
1859     /** @var string The minimum log level for YUI logging statements. */
1860     public $logLevel;
1861
1862     /**
1863      * @var array List of functions used by the YUI Loader group pattern recognition.
1864      */
1865     protected $jsconfigfunctions = array();
1866
1867     /**
1868      * Create a new group within the YUI_config system.
1869      *
1870      * @param string $name The name of the group. This must be unique and
1871      * not previously used.
1872      * @param array $config The configuration for this group.
1873      * @return void
1874      */
1875     public function add_group($name, $config) {
1876         if (isset($this->groups[$name])) {
1877             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1878         }
1879         $this->groups[$name] = $config;
1880     }
1881
1882     /**
1883      * Update an existing group configuration
1884      *
1885      * Note, any existing configuration for that group will be wiped out.
1886      * This includes module configuration.
1887      *
1888      * @param string $name The name of the group. This must be unique and
1889      * not previously used.
1890      * @param array $config The configuration for this group.
1891      * @return void
1892      */
1893     public function update_group($name, $config) {
1894         if (!isset($this->groups[$name])) {
1895             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.');
1896         }
1897         $this->groups[$name] = $config;
1898     }
1899
1900     /**
1901      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1902      *
1903      * Only the body of the function should be passed, and not the whole function wrapper.
1904      *
1905      * The JS function your write will be passed a single argument 'name' containing the
1906      * name of the module being loaded.
1907      *
1908      * @param $function String the body of the JavaScript function. This should be used i
1909      * @return string the name of the function to use in the group pattern configuration.
1910      */
1911     public function set_config_function($function) {
1912         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1913         if (isset($this->jsconfigfunctions[$configname])) {
1914             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1915         }
1916         $this->jsconfigfunctions[$configname] = $function;
1917         return '@' . $configname . '@';
1918     }
1919
1920     /**
1921      * Allow setting of the config function described in {@see set_config_function} from a file.
1922      * The contents of this file are then passed to set_config_function.
1923      *
1924      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1925      *
1926      * @param $file The path to the JavaScript function used for YUI configuration.
1927      * @return string the name of the function to use in the group pattern configuration.
1928      */
1929     public function set_config_source($file) {
1930         global $CFG;
1931         $cache = cache::make('core', 'yuimodules');
1932
1933         // Attempt to get the metadata from the cache.
1934         $keyname = 'configfn_' . $file;
1935         $fullpath = $CFG->dirroot . '/' . $file;
1936         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1937             $cache->delete($keyname);
1938             $configfn = file_get_contents($fullpath);
1939         } else {
1940             $configfn = $cache->get($keyname);
1941             if ($configfn === false) {
1942                 require_once($CFG->libdir . '/jslib.php');
1943                 $configfn = core_minify::js_files(array($fullpath));
1944                 $cache->set($keyname, $configfn);
1945             }
1946         }
1947         return $this->set_config_function($configfn);
1948     }
1949
1950     /**
1951      * Retrieve the list of JavaScript functions for YUI_config groups.
1952      *
1953      * @return string The complete set of config functions
1954      */
1955     public function get_config_functions() {
1956         $configfunctions = '';
1957         foreach ($this->jsconfigfunctions as $functionname => $function) {
1958             $configfunctions .= "var {$functionname} = function(me) {";
1959             $configfunctions .= $function;
1960             $configfunctions .= "};\n";
1961         }
1962         return $configfunctions;
1963     }
1964
1965     /**
1966      * Update the header JavaScript with any required modification for the YUI Loader.
1967      *
1968      * @param $js String The JavaScript to manipulate.
1969      * @return string the modified JS string.
1970      */
1971     public function update_header_js($js) {
1972         // Update the names of the the configFn variables.
1973         // The PHP json_encode function cannot handle literal names so we have to wrap
1974         // them in @ and then replace them with literals of the same function name.
1975         foreach ($this->jsconfigfunctions as $functionname => $function) {
1976             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1977         }
1978         return $js;
1979     }
1980
1981     /**
1982      * Add configuration for a specific module.
1983      *
1984      * @param string $name The name of the module to add configuration for.
1985      * @param array $config The configuration for the specified module.
1986      * @param string $group The name of the group to add configuration for.
1987      * If not specified, then this module is added to the global
1988      * configuration.
1989      * @return void
1990      */
1991     public function add_module_config($name, $config, $group = null) {
1992         if ($group) {
1993             if (!isset($this->groups[$name])) {
1994                 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.');
1995             }
1996             if (!isset($this->groups[$group]['modules'])) {
1997                 $this->groups[$group]['modules'] = array();
1998             }
1999             $modules = &$this->groups[$group]['modules'];
2000         } else {
2001             $modules = &$this->modules;
2002         }
2003         $modules[$name] = $config;
2004     }
2005
2006     /**
2007      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
2008      *
2009      * If js caching is disabled, metadata will not be served causing YUI to calculate
2010      * module dependencies as each module is loaded.
2011      *
2012      * If metadata does not exist it will be created and stored in a MUC entry.
2013      *
2014      * @return void
2015      */
2016     public function add_moodle_metadata() {
2017         global $CFG;
2018         if (!isset($this->groups['moodle'])) {
2019             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.');
2020         }
2021
2022         if (!isset($this->groups['moodle']['modules'])) {
2023             $this->groups['moodle']['modules'] = array();
2024         }
2025
2026         $cache = cache::make('core', 'yuimodules');
2027         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
2028             $metadata = array();
2029             $metadata = $this->get_moodle_metadata();
2030             $cache->delete('metadata');
2031         } else {
2032             // Attempt to get the metadata from the cache.
2033             if (!$metadata = $cache->get('metadata')) {
2034                 $metadata = $this->get_moodle_metadata();
2035                 $cache->set('metadata', $metadata);
2036             }
2037         }
2038
2039         // Merge with any metadata added specific to this page which was added manually.
2040         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
2041                 $metadata);
2042     }
2043
2044     /**
2045      * Determine the module metadata for all moodle YUI modules.
2046      *
2047      * This works through all modules capable of serving YUI modules, and attempts to get
2048      * metadata for each of those modules.
2049      *
2050      * @return array of module metadata
2051      */
2052     private function get_moodle_metadata() {
2053         $moodlemodules = array();
2054         // Core isn't a plugin type or subsystem - handle it seperately.
2055         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
2056             $moodlemodules = array_merge($moodlemodules, $module);
2057         }
2058
2059         // Handle other core subsystems.
2060         $subsystems = core_component::get_core_subsystems();
2061         foreach ($subsystems as $subsystem => $path) {
2062             if (is_null($path)) {
2063                 continue;
2064             }
2065             if ($module = $this->get_moodle_path_metadata($path)) {
2066                 $moodlemodules = array_merge($moodlemodules, $module);
2067             }
2068         }
2069
2070         // And finally the plugins.
2071         $plugintypes = core_component::get_plugin_types();
2072         foreach ($plugintypes as $plugintype => $pathroot) {
2073             $pluginlist = core_component::get_plugin_list($plugintype);
2074             foreach ($pluginlist as $plugin => $path) {
2075                 if ($module = $this->get_moodle_path_metadata($path)) {
2076                     $moodlemodules = array_merge($moodlemodules, $module);
2077                 }
2078             }
2079         }
2080
2081         return $moodlemodules;
2082     }
2083
2084     /**
2085      * Helper function process and return the YUI metadata for all of the modules under the specified path.
2086      *
2087      * @param string $path the UNC path to the YUI src directory.
2088      * @return array the complete array for frankenstyle directory.
2089      */
2090     private function get_moodle_path_metadata($path) {
2091         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
2092         $baseyui = $path . '/yui/src';
2093         $modules = array();
2094         if (is_dir($baseyui)) {
2095             $items = new DirectoryIterator($baseyui);
2096             foreach ($items as $item) {
2097                 if ($item->isDot() or !$item->isDir()) {
2098                     continue;
2099                 }
2100                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
2101                 if (!is_readable($metafile)) {
2102                     continue;
2103                 }
2104                 $metadata = file_get_contents($metafile);
2105                 $modules = array_merge($modules, (array) json_decode($metadata));
2106             }
2107         }
2108         return $modules;
2109     }
2110
2111     /**
2112      * Define YUI modules which we have been required to patch between releases.
2113      *
2114      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2115      * external CDN which will serve the true authoritative copy of the code without our patches.
2116      *
2117      * @param string $combobase The local combobase
2118      * @param string $yuiversion The current YUI version
2119      * @param int $patchlevel The patch level we're working to for YUI
2120      * @param array $patchedmodules An array containing the names of the patched modules
2121      * @return void
2122      */
2123     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2124         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2125         $subversion = $yuiversion . '_' . $patchlevel;
2126
2127         if ($this->comboBase == $combobase) {
2128             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2129             // loader. We just need to specify a different root which includes a slightly different YUI version number
2130             // to include our patchlevel.
2131             $patterns = array();
2132             $modules = array();
2133             foreach ($patchedmodules as $modulename) {
2134                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2135                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2136                 // loaded when the module is loaded anyway.
2137                 $patterns[$modulename] = array(
2138                     'group' => 'yui-patched',
2139                 );
2140                 $modules[$modulename] = array();
2141             }
2142
2143             // Actually add the patch group here.
2144             $this->add_group('yui-patched', array(
2145                 'combine' => true,
2146                 'root' => $subversion . '/',
2147                 'patterns' => $patterns,
2148                 'modules' => $modules,
2149             ));
2150
2151         } else {
2152             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2153             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2154             // local base in browser caches.
2155             $fullpathbase = $combobase . $subversion . '/';
2156             foreach ($patchedmodules as $modulename) {
2157                 $this->modules[$modulename] = array(
2158                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2159                 );
2160             }
2161         }
2162     }
2163 }
2164
2165 /**
2166  * Invalidate all server and client side template caches.
2167  */
2168 function template_reset_all_caches() {
2169     global $CFG;
2170
2171     $next = time();
2172     if (isset($CFG->templaterev) and $next <= $CFG->templaterev and $CFG->templaterev - $next < 60 * 60) {
2173         // This resolves problems when reset is requested repeatedly within 1s,
2174         // the < 1h condition prevents accidental switching to future dates
2175         // because we might not recover from it.
2176         $next = $CFG->templaterev + 1;
2177     }
2178
2179     set_config('templaterev', $next);
2180 }
2181
2182 /**
2183  * Invalidate all server and client side JS caches.
2184  */
2185 function js_reset_all_caches() {
2186     global $CFG;
2187
2188     $next = time();
2189     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2190         // This resolves problems when reset is requested repeatedly within 1s,
2191         // the < 1h condition prevents accidental switching to future dates
2192         // because we might not recover from it.
2193         $next = $CFG->jsrev+1;
2194     }
2195
2196     set_config('jsrev', $next);
2197 }