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'              => $page->theme->use_svg_icons(),
 326                 'usertimezone'          => usertimezone(),
 327                 'courseId'              => isset($courseid) ? (int) $courseid : 0,
 328                 'courseContextId'       => isset($coursecontext) ? $coursecontext->id : 0,
 329                 'contextid'             => $contextid,
 330                 'contextInstanceId'     => (int) $contextinstanceid,
 331                 'langrev'               => get_string_manager()->get_revision(),
 332                 'templaterev'           => $this->get_templaterev()
 333             );
 334             if ($CFG->debugdeveloper) {
 335                 $this->M_cfg['developerdebug'] = true;
 336             }
 337             if (defined('BEHAT_SITE_RUNNING')) {
 338                 $this->M_cfg['behatsiterunning'] = true;
 339             }
 340
 341         }
 342         return $this->M_cfg;
 343     }
 344
 345     /**
 346      * Initialise with the bits of JavaScript that every Moodle page should have.
 347      *
 348      * @param moodle_page $page
 349      * @param core_renderer $renderer
 350      */
 351     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 352         global $CFG;
 353
 354         // Init the js config.
 355         $this->get_config_for_javascript($page, $renderer);
 356
 357         // Accessibility stuff.
 358         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 359
 360         // Add strings used on many pages.
 361         $this->string_for_js('confirmation', 'admin');
 362         $this->string_for_js('cancel', 'moodle');
 363         $this->string_for_js('yes', 'moodle');
 364
 365         // Alter links in top frame to break out of frames.
 366         if ($page->pagelayout === 'frametop') {
 367             $this->js_init_call('M.util.init_frametop');
 368         }
 369
 370         // Include block drag/drop if editing is on
 371         if ($page->user_is_editing()) {
 372             $params = array(
 373                 'regions' => $page->blocks->get_regions(),
 374                 'pagehash' => $page->get_edited_page_hash(),
 375             );
 376             if (!empty($page->cm->id)) {
 377                 $params['cmid'] = $page->cm->id;
 378             }
 379             // Strings for drag and drop.
 380             $this->strings_for_js(array('movecontent',
 381                                         'tocontent',
 382                                         'emptydragdropregion'),
 383                                   'moodle');
 384             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 385             $page->requires->js_call_amd('core_block/edit', 'init', ['pagehash' => $page->get_edited_page_hash()]);
 386         }
 387
 388         // Include the YUI CSS Modules.
 389         $page->requires->set_yuicssmodules($page->theme->yuicssmodules);
 390     }
 391
 392     /**
 393      * Determine the correct JS Revision to use for this load.
 394      *
 395      * @return int the jsrev to use.
 396      */
 397     public function get_jsrev() {
 398         global $CFG;
 399
 400         if (empty($CFG->cachejs)) {
 401             $jsrev = -1;
 402         } else if (empty($CFG->jsrev)) {
 403             $jsrev = 1;
 404         } else {
 405             $jsrev = $CFG->jsrev;
 406         }
 407
 408         return $jsrev;
 409     }
 410
 411     /**
 412      * Determine the correct Template revision to use for this load.
 413      *
 414      * @return int the templaterev to use.
 415      */
 416     protected function get_templaterev() {
 417         global $CFG;
 418
 419         if (empty($CFG->cachetemplates)) {
 420             $templaterev = -1;
 421         } else if (empty($CFG->templaterev)) {
 422             $templaterev = 1;
 423         } else {
 424             $templaterev = $CFG->templaterev;
 425         }
 426
 427         return $templaterev;
 428     }
 429
 430     /**
 431      * Ensure that the specified JavaScript file is linked to from this page.
 432      *
 433      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 434      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 435      *
 436      * By default the link is put at the end of the page, since this gives best page-load performance.
 437      *
 438      * Even if a particular script is requested more than once, it will only be linked
 439      * to once.
 440      *
 441      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 442      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 443      * @param bool $inhead initialise in head
 444      */
 445     public function js($url, $inhead = false) {
 446         if ($url == '/question/qengine.js') {
 447             debugging('The question/qengine.js has been deprecated. ' .
 448                 'Please use core_question/question_engine', DEBUG_DEVELOPER);
 449         }
 450         $url = $this->js_fix_url($url);
 451         $where = $inhead ? 'head' : 'footer';
 452         $this->jsincludes[$where][$url->out()] = $url;
 453     }
 454
 455     /**
 456      * Request inclusion of jQuery library in the page.
 457      *
 458      * NOTE: this should not be used in official Moodle distribution!
 459      *
 460      * {@link https://moodledev.io/docs/guides/javascript/jquery}
 461      */
 462     public function jquery() {
 463         $this->jquery_plugin('jquery');
 464     }
 465
 466     /**
 467      * Request inclusion of jQuery plugin.
 468      *
 469      * NOTE: this should not be used in official Moodle distribution!
 470      *
 471      * jQuery plugins are located in plugin/jquery/* subdirectory,
 472      * plugin/jquery/plugins.php lists all available plugins.
 473      *
 474      * Included core plugins:
 475      *   - jQuery UI
 476      *
 477      * Add-ons may include extra jQuery plugins in jquery/ directory,
 478      * plugins.php file defines the mapping between plugin names and
 479      * necessary page includes.
 480      *
 481      * Examples:
 482      * <code>
 483      *   // file: mod/xxx/view.php
 484      *   $PAGE->requires->jquery();
 485      *   $PAGE->requires->jquery_plugin('ui');
 486      *   $PAGE->requires->jquery_plugin('ui-css');
 487      * </code>
 488      *
 489      * <code>
 490      *   // file: theme/yyy/lib.php
 491      *   function theme_yyy_page_init(moodle_page $page) {
 492      *       $page->requires->jquery();
 493      *       $page->requires->jquery_plugin('ui');
 494      *       $page->requires->jquery_plugin('ui-css');
 495      *   }
 496      * </code>
 497      *
 498      * <code>
 499      *   // file: blocks/zzz/block_zzz.php
 500      *   public function get_required_javascript() {
 501      *       parent::get_required_javascript();
 502      *       $this->page->requires->jquery();
 503      *       $page->requires->jquery_plugin('ui');
 504      *       $page->requires->jquery_plugin('ui-css');
 505      *   }
 506      * </code>
 507      *
 508      * {@link https://moodledev.io/docs/guides/javascript/jquery}
 509      *
 510      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 511      * @param string $component name of the component
 512      * @return bool success
 513      */
 514     public function jquery_plugin($plugin, $component = 'core') {
 515         global $CFG;
 516
 517         if ($this->headdone) {
 518             debugging('Can not add jQuery plugins after starting page output!');
 519             return false;
 520         }
 521
 522         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css'))) {
 523             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 524             $component = 'core';
 525         } else if ($component !== 'core' and strpos($component, '_') === false) {
 526             // Let's normalise the legacy activity names, Frankenstyle rulez!
 527             $component = 'mod_' . $component;
 528         }
 529
 530         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 531             // Make sure the jQuery itself is always loaded first,
 532             // the order of all other plugins depends on order of $PAGE_>requires->.
 533             $this->jquery_plugin('jquery', 'core');
 534         }
 535
 536         if (isset($this->jqueryplugins[$plugin])) {
 537             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 538             return true;
 539         }
 540
 541         $componentdir = core_component::get_component_directory($component);
 542         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 543             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 544             return false;
 545         }
 546
 547         $plugins = array();
 548         require("$componentdir/jquery/plugins.php");
 549
 550         if (!isset($plugins[$plugin])) {
 551             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 552             return false;
 553         }
 554
 555         $this->jqueryplugins[$plugin] = new stdClass();
 556         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 557         $this->jqueryplugins[$plugin]->component = $component;
 558         $this->jqueryplugins[$plugin]->urls      = array();
 559
 560         foreach ($plugins[$plugin]['files'] as $file) {
 561             if ($CFG->debugdeveloper) {
 562                 if (!file_exists("$componentdir/jquery/$file")) {
 563                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 564                     continue;
 565                 }
 566                 $file = str_replace('.min.css', '.css', $file);
 567                 $file = str_replace('.min.js', '.js', $file);
 568             }
 569             if (!file_exists("$componentdir/jquery/$file")) {
 570                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 571                 continue;
 572             }
 573             if (!empty($CFG->slasharguments)) {
 574                 $url = new moodle_url("/theme/jquery.php");
 575                 $url->set_slashargument("/$component/$file");
 576
 577             } else {
 578                 // This is not really good, we need slasharguments for relative links, this means no caching...
 579                 $path = realpath("$componentdir/jquery/$file");
 580                 if (strpos($path, $CFG->dirroot) === 0) {
 581                     $url = $CFG->wwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 582                     // Replace all occurences of backslashes characters in url to forward slashes.
 583                     $url = str_replace('\\', '/', $url);
 584                     $url = new moodle_url($url);
 585                 } else {
 586                     // Bad luck, fix your server!
 587                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 588                     continue;
 589                 }
 590             }
 591             $this->jqueryplugins[$plugin]->urls[] = $url;
 592         }
 593
 594         return true;
 595     }
 596
 597     /**
 598      * Request replacement of one jQuery plugin by another.
 599      *
 600      * This is useful when themes want to replace the jQuery UI theme,
 601      * the problem is that theme can not prevent others from including the core ui-css plugin.
 602      *
 603      * Example:
 604      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 605      *  2/ write theme/yourtheme/jquery/plugins.php
 606      *  3/ init jQuery from theme
 607      *
 608      * <code>
 609      *   // file theme/yourtheme/lib.php
 610      *   function theme_yourtheme_page_init($page) {
 611      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 612      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 613      *   }
 614      * </code>
 615      *
 616      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 617      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 618      *
 619      * {@link https://moodledev.io/docs/guides/javascript/jquery}
 620      *
 621      * @param string $oldplugin original plugin
 622      * @param string $newplugin the replacement
 623      */
 624     public function jquery_override_plugin($oldplugin, $newplugin) {
 625         if ($this->headdone) {
 626             debugging('Can not override jQuery plugins after starting page output!');
 627             return;
 628         }
 629         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 630     }
 631
 632     /**
 633      * Return jQuery related markup for page start.
 634      * @return string
 635      */
 636     protected function get_jquery_headcode() {
 637         if (empty($this->jqueryplugins['jquery'])) {
 638             // If nobody requested jQuery then do not bother to load anything.
 639             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 640             return '';
 641         }
 642
 643         $included = array();
 644         $urls = array();
 645
 646         foreach ($this->jqueryplugins as $name => $unused) {
 647             if (isset($included[$name])) {
 648                 continue;
 649             }
 650             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 651                 // The following loop tries to resolve the replacements,
 652                 // use max 100 iterations to prevent infinite loop resulting
 653                 // in blank page.
 654                 $cyclic = true;
 655                 $oldname = $name;
 656                 for ($i=0; $i<100; $i++) {
 657                     $name = $this->jquerypluginoverrides[$name];
 658                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 659                         $cyclic = false;
 660                         break;
 661                     }
 662                 }
 663                 if ($cyclic) {
 664                     // We can not do much with cyclic references here, let's use the old plugin.
 665                     $name = $oldname;
 666                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 667
 668                 } else if (empty($name)) {
 669                     // Developer requested removal of the plugin.
 670                     continue;
 671
 672                 } else if (!isset($this->jqueryplugins[$name])) {
 673                     debugging("Unknown jQuery override plugin '$name' detected");
 674                     $name = $oldname;
 675
 676                 } else if (isset($included[$name])) {
 677                     // The plugin was already included, easy.
 678                     continue;
 679                 }
 680             }
 681
 682             $plugin = $this->jqueryplugins[$name];
 683             $urls = array_merge($urls, $plugin->urls);
 684             $included[$name] = true;
 685         }
 686
 687         $output = '';
 688         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 689         foreach ($urls as $url) {
 690             if (preg_match('/\.js$/', $url)) {
 691                 $output .= html_writer::script('', $url);
 692             } else if (preg_match('/\.css$/', $url)) {
 693                 $attributes['href'] = $url;
 694                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 695             }
 696         }
 697
 698         return $output;
 699     }
 700
 701     /**
 702      * Returns the actual url through which a JavaScript file is served.
 703      *
 704      * @param moodle_url|string $url full moodle url, or shortened path to script.
 705      * @throws coding_exception if the given $url isn't a shortened url starting with / or a moodle_url instance.
 706      * @return moodle_url
 707      */
 708     protected function js_fix_url($url) {
 709         global $CFG;
 710
 711         if ($url instanceof moodle_url) {
 712             // If the URL is external to Moodle, it won't be handled by Moodle (!).
 713             if ($url->is_local_url()) {
 714                 $localurl = $url->out_as_local_url();
 715                 // Check if the URL points to a Moodle PHP resource.
 716                 if (strpos($localurl, '.php') !== false) {
 717                     // It's a Moodle PHP resource e.g. a resource already served by the proper Moodle Handler.
 718                     return $url;
 719                 }
 720                 // It's a local resource: we need to further examine it.
 721                 return $this->js_fix_url($url->out_as_local_url(false));
 722             }
 723             // The URL is not a Moodle resource.
 724             return $url;
 725         } else if (null !== $url && strpos($url, '/') === 0) {
 726             // Fix the admin links if needed.
 727             if ($CFG->admin !== 'admin') {
 728                 if (strpos($url, "/admin/") === 0) {
 729                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 730                 }
 731             }
 732             if (debugging()) {
 733                 // Check file existence only when in debug mode.
 734                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 735                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 736                 }
 737             }
 738             if (substr($url, -3) === '.js') {
 739                 $jsrev = $this->get_jsrev();
 740                 if (empty($CFG->slasharguments)) {
 741                     return new moodle_url('/lib/javascript.php', ['rev' => $jsrev, 'jsfile' => $url]);
 742                 } else {
 743                     $returnurl = new moodle_url('/lib/javascript.php');
 744                     $returnurl->set_slashargument('/'.$jsrev.$url);
 745                     return $returnurl;
 746                 }
 747             } else {
 748                 return new moodle_url($url);
 749             }
 750         } else {
 751             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 752         }
 753     }
 754
 755     /**
 756      * Find out if JS module present and return details.
 757      *
 758      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 759      * @return array description of module or null if not found
 760      */
 761     protected function find_module($component) {
 762         global $CFG, $PAGE;
 763
 764         $module = null;
 765
 766         if (strpos($component, 'core_') === 0) {
 767             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 768             // so that we do nto have to repeat the definition of these modules over and over again.
 769             switch($component) {
 770                 case 'core_filepicker':
 771                     $module = array('name'     => 'core_filepicker',
 772                                     'fullpath' => '/repository/filepicker.js',
 773                                     'requires' => array(
 774                                         'base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form',
 775                                         'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin',
 776                                         'escape', 'moodle-core_filepicker', 'moodle-core-notification-dialogue'
 777                                     ),
 778                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 779                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 780                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 781                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 782                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 783                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 784                                                         array('referencesexist', 'repository'), array('select', 'repository')
 785                                                     ));
 786                     break;
 787                 case 'core_comment':
 788                     $module = array('name'     => 'core_comment',
 789                                     'fullpath' => '/comment/comment.js',
 790                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay', 'escape'),
 791                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 792                                 );
 793                     break;
 794                 case 'core_role':
 795                     $module = array('name'     => 'core_role',
 796                                     'fullpath' => '/admin/roles/module.js',
 797                                     'requires' => array('node', 'cookie'));
 798                     break;
 799                 case 'core_completion':
 800                     break;
 801                 case 'core_message':
 802                     $module = array('name'     => 'core_message',
 803                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 804                                     'fullpath' => '/message/module.js');
 805                     break;
 806                 case 'core_group':
 807                     $module = array('name'     => 'core_group',
 808                                     'fullpath' => '/group/module.js',
 809                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 810                     break;
 811                 case 'core_question_engine':
 812                     $module = array('name'     => 'core_question_engine',
 813                                     'fullpath' => '/question/qengine.js',
 814                                     'requires' => array('node', 'event'));
 815                     break;
 816                 case 'core_rating':
 817                     $module = array('name'     => 'core_rating',
 818                                     'fullpath' => '/rating/module.js',
 819                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 820                     break;
 821                 case 'core_dndupload':
 822                     $module = array('name'     => 'core_dndupload',
 823                                     'fullpath' => '/lib/form/dndupload.js',
 824                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 825                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 826                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesfile', 'error'),
 827                                                         array('sizegb', 'moodle'), array('sizemb', 'moodle'), array('sizekb', 'moodle'), array('sizeb', 'moodle'),
 828                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 829                                                         array('changesmadereallygoaway', 'moodle'), array('complete', 'moodle')
 830                                                     ));
 831                     break;
 832             }
 833
 834         } else {
 835             if ($dir = core_component::get_component_directory($component)) {
 836                 if (file_exists("$dir/module.js")) {
 837                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 838                         $dir = substr($dir, strlen($CFG->dirroot));
 839                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 840                     }
 841                 }
 842             }
 843         }
 844
 845         return $module;
 846     }
 847
 848     /**
 849      * Append YUI3 module to default YUI3 JS loader.
 850      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 851      *
 852      * @param string|array $module name of module (details are autodetected), or full module specification as array
 853      * @return void
 854      */
 855     public function js_module($module) {
 856         global $CFG;
 857
 858         if (empty($module)) {
 859             throw new coding_exception('Missing YUI3 module name or full description.');
 860         }
 861
 862         if (is_string($module)) {
 863             $module = $this->find_module($module);
 864         }
 865
 866         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 867             throw new coding_exception('Missing YUI3 module details.');
 868         }
 869
 870         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 871         // Add all needed strings.
 872         if (!empty($module['strings'])) {
 873             foreach ($module['strings'] as $string) {
 874                 $identifier = $string[0];
 875                 $component = isset($string[1]) ? $string[1] : 'moodle';
 876                 $a = isset($string[2]) ? $string[2] : null;
 877                 $this->string_for_js($identifier, $component, $a);
 878             }
 879         }
 880         unset($module['strings']);
 881
 882         // Process module requirements and attempt to load each. This allows
 883         // moodle modules to require each other.
 884         if (!empty($module['requires'])){
 885             foreach ($module['requires'] as $requirement) {
 886                 $rmodule = $this->find_module($requirement);
 887                 if (is_array($rmodule)) {
 888                     $this->js_module($rmodule);
 889                 }
 890             }
 891         }
 892
 893         if ($this->headdone) {
 894             $this->extramodules[$module['name']] = $module;
 895         } else {
 896             $this->YUI_config->add_module_config($module['name'], $module);
 897         }
 898     }
 899
 900     /**
 901      * Returns true if the module has already been loaded.
 902      *
 903      * @param string|array $module
 904      * @return bool True if the module has already been loaded
 905      */
 906     protected function js_module_loaded($module) {
 907         if (is_string($module)) {
 908             $modulename = $module;
 909         } else {
 910             $modulename = $module['name'];
 911         }
 912         return array_key_exists($modulename, $this->YUI_config->modules) ||
 913                array_key_exists($modulename, $this->extramodules);
 914     }
 915
 916     /**
 917      * Ensure that the specified CSS file is linked to from this page.
 918      *
 919      * Because stylesheet links must go in the <head> part of the HTML, you must call
 920      * this function before {@link get_head_code()} is called. That normally means before
 921      * the call to print_header. If you call it when it is too late, an exception
 922      * will be thrown.
 923      *
 924      * Even if a particular style sheet is requested more than once, it will only
 925      * be linked to once.
 926      *
 927      * Please note use of this feature is strongly discouraged,
 928      * it is suitable only for places where CSS is submitted directly by teachers.
 929      * (Students must not be allowed to submit any external CSS because it may
 930      * contain embedded javascript!). Example of correct use is mod/data.
 931      *
 932      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 933      *   For example:
 934      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 935      */
 936     public function css($stylesheet) {
 937         global $CFG;
 938
 939         if ($this->headdone) {
 940             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 941         }
 942
 943         if ($stylesheet instanceof moodle_url) {
 944             // ok
 945         } else if (strpos($stylesheet, '/') === 0) {
 946             $stylesheet = new moodle_url($stylesheet);
 947         } else {
 948             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 949         }
 950
 951         $this->cssurls[$stylesheet->out()] = $stylesheet;
 952     }
 953
 954     /**
 955      * Add theme stylesheet to page - do not use from plugin code,
 956      * this should be called only from the core renderer!
 957      *
 958      * @param moodle_url $stylesheet
 959      * @return void
 960      */
 961     public function css_theme(moodle_url $stylesheet) {
 962         $this->cssthemeurls[] = $stylesheet;
 963     }
 964
 965     /**
 966      * Ensure that a skip link to a given target is printed at the top of the <body>.
 967      *
 968      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 969      * will be thrown). That normally means you must call this before the call to print_header.
 970      *
 971      * If you ask for a particular skip link to be printed, it is then your responsibility
 972      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 973      * page, so that the skip link goes somewhere.
 974      *
 975      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 976      *
 977      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 978      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 979      */
 980     public function skip_link_to($target, $linktext) {
 981         if ($this->topofbodydone) {
 982             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 983             return;
 984         }
 985         $this->skiplinks[$target] = $linktext;
 986     }
 987
 988     /**
 989      * !!!DEPRECATED!!! please use js_init_call() if possible
 990      * Ensure that the specified JavaScript function is called from an inline script
 991      * somewhere on this page.
 992      *
 993      * By default the call will be put in a script tag at the
 994      * end of the page after initialising Y instance, since this gives best page-load
 995      * performance and allows you to use YUI3 library.
 996      *
 997      * If you request that a particular function is called several times, then
 998      * that is what will happen (unlike linking to a CSS or JS file, where only
 999      * one link will be output).
1000      *
1001      * The main benefit of the method is the automatic encoding of all function parameters.
1002      *
1003      * @deprecated
1004      *
1005      * @param string $function the name of the JavaScritp function to call. Can
1006      *      be a compound name like 'Y.Event.purgeElement'. Can also be
1007      *      used to create and object by using a 'function name' like 'new user_selector'.
1008      * @param array $arguments and array of arguments to be passed to the function.
1009      *      When generating the function call, this will be escaped using json_encode,
1010      *      so passing objects and arrays should work.
1011      * @param bool $ondomready If tru the function is only called when the dom is
1012      *      ready for manipulation.
1013      * @param int $delay The delay before the function is called.
1014      */
1015     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
1016         $where = $ondomready ? 'ondomready' : 'normal';
1017         $this->jscalls[$where][] = array($function, $arguments, $delay);
1018     }
1019
1020     /**
1021      * This function appends a block of code to the AMD specific javascript block executed
1022      * in the page footer, just after loading the requirejs library.
1023      *
1024      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
1025      *
1026      * @param string $code The JS code to append.
1027      */
1028     public function js_amd_inline($code) {
1029         $this->amdjscode[] = $code;
1030     }
1031
1032     /**
1033      * Load an AMD module and eventually call its method.
1034      *
1035      * This function creates a minimal inline JS snippet that requires an AMD module and eventually calls a single
1036      * function from the module with given arguments. If it is called multiple times, it will be create multiple
1037      * snippets.
1038      *
1039      * @param string $fullmodule The name of the AMD module to load, formatted as <component name>/<module name>.
1040      * @param string $func Optional function from the module to call, defaults to just loading the AMD module.
1041      * @param array $params The params to pass to the function (will be serialized into JSON).
1042      */
1043     public function js_call_amd($fullmodule, $func = null, $params = array()) {
1044         global $CFG;
1045
1046         $modulepath = explode('/', $fullmodule);
1047
1048         $modname = clean_param(array_shift($modulepath), PARAM_COMPONENT);
1049         foreach ($modulepath as $module) {
1050             $modname .= '/' . clean_param($module, PARAM_ALPHANUMEXT);
1051         }
1052
1053         $functioncode = [];
1054         if ($func !== null) {
1055             $func = clean_param($func, PARAM_ALPHANUMEXT);
1056
1057             $jsonparams = array();
1058             foreach ($params as $param) {
1059                 $jsonparams[] = json_encode($param);
1060             }
1061             $strparams = implode(', ', $jsonparams);
1062             if ($CFG->debugdeveloper) {
1063                 $toomanyparamslimit = 1024;
1064                 if (strlen($strparams) > $toomanyparamslimit) {
1065                     debugging('Too much data passed as arguments to js_call_amd("' . $fullmodule . '", "' . $func .
1066                         '"). Generally there are better ways to pass lots of data from PHP to JavaScript, for example via Ajax, ' .
1067                         'data attributes, ... . This warning is triggered if the argument string becomes longer than ' .
1068                         $toomanyparamslimit . ' characters.', DEBUG_DEVELOPER);
1069                 }
1070             }
1071
1072             $functioncode[] = "amd.{$func}({$strparams});";
1073         }
1074
1075         $functioncode[] = "M.util.js_complete('{$modname}');";
1076
1077         $initcode = implode(' ', $functioncode);
1078         $js = "M.util.js_pending('{$modname}'); require(['{$modname}'], function(amd) {{$initcode}});";
1079
1080         $this->js_amd_inline($js);
1081     }
1082
1083     /**
1084      * Creates a JavaScript function call that requires one or more modules to be loaded.
1085      *
1086      * This function can be used to include all of the standard YUI module types within JavaScript:
1087      *     - YUI3 modules    [node, event, io]
1088      *     - YUI2 modules    [yui2-*]
1089      *     - Moodle modules  [moodle-*]
1090      *     - Gallery modules [gallery-*]
1091      *
1092      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1093      * @see js_call_amd()
1094      *
1095      * @param array|string $modules One or more modules
1096      * @param string $function The function to call once modules have been loaded
1097      * @param array $arguments An array of arguments to pass to the function
1098      * @param string $galleryversion Deprecated: The gallery version to use
1099      * @param bool $ondomready
1100      */
1101     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1102         if (!is_array($modules)) {
1103             $modules = array($modules);
1104         }
1105
1106         if ($galleryversion != null) {
1107             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1108         }
1109
1110         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1111         if ($ondomready) {
1112             $jscode = "Y.on('domready', function() { $jscode });";
1113         }
1114         $this->jsinitcode[] = $jscode;
1115     }
1116
1117     /**
1118      * Set the CSS Modules to be included from YUI.
1119      *
1120      * @param array $modules The list of YUI CSS Modules to include.
1121      */
1122     public function set_yuicssmodules(array $modules = array()) {
1123         $this->yuicssmodules = $modules;
1124     }
1125
1126     /**
1127      * Ensure that the specified JavaScript function is called from an inline script
1128      * from page footer.
1129      *
1130      * @param string $function the name of the JavaScritp function to with init code,
1131      *      usually something like 'M.mod_mymodule.init'
1132      * @param array $extraarguments and array of arguments to be passed to the function.
1133      *      The first argument is always the YUI3 Y instance with all required dependencies
1134      *      already loaded.
1135      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1136      * @param array $module JS module specification array
1137      */
1138     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1139         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1140         if (!$module) {
1141             // Detect module automatically.
1142             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1143                 $module = $this->find_module($matches[1]);
1144             }
1145         }
1146
1147         $this->js_init_code($jscode, $ondomready, $module);
1148     }
1149
1150     /**
1151      * Add short static javascript code fragment to page footer.
1152      * This is intended primarily for loading of js modules and initialising page layout.
1153      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1154      * may override it.
1155      *
1156      * @param string $jscode
1157      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1158      * @param array $module JS module specification array
1159      */
1160     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1161         $jscode = trim($jscode, " ;\n"). ';';
1162
1163         $uniqid = html_writer::random_id();
1164         $startjs = " M.util.js_pending('" . $uniqid . "');";
1165         $endjs = " M.util.js_complete('" . $uniqid . "');";
1166
1167         if ($module) {
1168             $this->js_module($module);
1169             $modulename = $module['name'];
1170             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1171         }
1172
1173         if ($ondomready) {
1174             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1175         }
1176
1177         $this->jsinitcode[] = $jscode;
1178     }
1179
1180     /**
1181      * Make a language string available to JavaScript.
1182      *
1183      * All the strings will be available in a M.str object in the global namespace.
1184      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1185      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1186      * equivalent in the current language.
1187      *
1188      * The arguments to this function are just like the arguments to get_string
1189      * except that $component is not optional, and there are some aspects to consider
1190      * when the string contains {$a} placeholder.
1191      *
1192      * If the string does not contain any {$a} placeholder, you can simply use
1193      * M.str.component.identifier to obtain it. If you prefer, you can call
1194      * M.util.get_string(identifier, component) to get the same result.
1195      *
1196      * If you need to use {$a} placeholders, there are two options. Either the
1197      * placeholder should be substituted in PHP on server side or it should
1198      * be substituted in Javascript at client side.
1199      *
1200      * To substitute the placeholder at server side, just provide the required
1201      * value for the placeholder when you require the string. Because each string
1202      * is only stored once in the JavaScript (based on $identifier and $module)
1203      * you cannot get the same string with two different values of $a. If you try,
1204      * an exception will be thrown. Once the placeholder is substituted, you can
1205      * use M.str or M.util.get_string() as shown above:
1206      *
1207      *     // Require the string in PHP and replace the placeholder.
1208      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1209      *     // Use the result of the substitution in Javascript.
1210      *     alert(M.str.moodle.fullnamedisplay);
1211      *
1212      * To substitute the placeholder at client side, use M.util.get_string()
1213      * function. It implements the same logic as {@link get_string()}:
1214      *
1215      *     // Require the string in PHP but keep {$a} as it is.
1216      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1217      *     // Provide the values on the fly in Javascript.
1218      *     user = { firstname : 'Harry', lastname : 'Potter' }
1219      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1220      *
1221      * If you do need the same string expanded with different $a values in PHP
1222      * on server side, then the solution is to put them in your own data structure
1223      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1224      *
1225      * @param string $identifier the desired string.
1226      * @param string $component the language file to look in.
1227      * @param mixed $a any extra data to add into the string (optional).
1228      */
1229     public function string_for_js($identifier, $component, $a = null) {
1230         if (!$component) {
1231             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1232         }
1233         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1234             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1235                     "from lang file '$component' with different \$a parameter?");
1236         }
1237         if (!isset($this->stringsforjs[$component][$identifier])) {
1238             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1239             $this->stringsforjs_as[$component][$identifier] = $a;
1240         }
1241     }
1242
1243     /**
1244      * Make an array of language strings available for JS.
1245      *
1246      * This function calls the above function {@link string_for_js()} for each requested
1247      * string in the $identifiers array that is passed to the argument for a single module
1248      * passed in $module.
1249      *
1250      * <code>
1251      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1252      *
1253      * // The above is identical to calling:
1254      *
1255      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1256      * $PAGE->requires->string_for_js('two', 'mymod');
1257      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1258      * </code>
1259      *
1260      * @param array $identifiers An array of desired strings
1261      * @param string $component The module to load for
1262      * @param mixed $a This can either be a single variable that gets passed as extra
1263      *         information for every string or it can be an array of mixed data where the
1264      *         key for the data matches that of the identifier it is meant for.
1265      *
1266      */
1267     public function strings_for_js($identifiers, $component, $a = null) {
1268         foreach ($identifiers as $key => $identifier) {
1269             if (is_array($a) && array_key_exists($key, $a)) {
1270                 $extra = $a[$key];
1271             } else {
1272                 $extra = $a;
1273             }
1274             $this->string_for_js($identifier, $component, $extra);
1275         }
1276     }
1277
1278     /**
1279      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1280      *
1281      * Make some data from PHP available to JavaScript code.
1282      *
1283      * For example, if you call
1284      * <pre>
1285      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1286      * </pre>
1287      * then in JavsScript mydata.name will be 'Moodle'.
1288      *
1289      * @deprecated
1290      * @param string $variable the the name of the JavaScript variable to assign the data to.
1291      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1292      *      should be considered an experimental feature.
1293      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1294      *      so passing objects and arrays should work.
1295      * @param bool $inhead initialise in head
1296      * @return void
1297      */
1298     public function data_for_js($variable, $data, $inhead=false) {
1299         $where = $inhead ? 'head' : 'footer';
1300         $this->jsinitvariables[$where][] = array($variable, $data);
1301     }
1302
1303     /**
1304      * Creates a YUI event handler.
1305      *
1306      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1307      * @param string $event A valid DOM event (click, mousedown, change etc.)
1308      * @param string $function The name of the function to call
1309      * @param array  $arguments An optional array of argument parameters to pass to the function
1310      */
1311     public function event_handler($selector, $event, $function, array $arguments = null) {
1312         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1313     }
1314
1315     /**
1316      * Returns code needed for registering of event handlers.
1317      * @return string JS code
1318      */
1319     protected function get_event_handler_code() {
1320         $output = '';
1321         foreach ($this->eventhandlers as $h) {
1322             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1323         }
1324         return $output;
1325     }
1326
1327     /**
1328      * Get the inline JavaScript code that need to appear in a particular place.
1329      * @param bool $ondomready
1330      * @return string
1331      */
1332     protected function get_javascript_code($ondomready) {
1333         $where = $ondomready ? 'ondomready' : 'normal';
1334         $output = '';
1335         if ($this->jscalls[$where]) {
1336             foreach ($this->jscalls[$where] as $data) {
1337                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1338             }
1339             if (!empty($ondomready)) {
1340                 $output = "    Y.on('domready', function() {\n$output\n});";
1341             }
1342         }
1343         return $output;
1344     }
1345
1346     /**
1347      * Returns js code to be executed when Y is available.
1348      * @return string
1349      */
1350     protected function get_javascript_init_code() {
1351         if (count($this->jsinitcode)) {
1352             return implode("\n", $this->jsinitcode) . "\n";
1353         }
1354         return '';
1355     }
1356
1357     /**
1358      * Returns js code to load amd module loader, then insert inline script tags
1359      * that contain require() calls using RequireJS.
1360      * @return string
1361      */
1362     protected function get_amd_footercode() {
1363         global $CFG;
1364         $output = '';
1365
1366         // We will cache JS if cachejs is not set, or it is true.
1367         $cachejs = !isset($CFG->cachejs) || $CFG->cachejs;
1368         $jsrev = $this->get_jsrev();
1369
1370         $jsloader = new moodle_url('/lib/javascript.php');
1371         $jsloader->set_slashargument('/' . $jsrev . '/');
1372         $requirejsloader = new moodle_url('/lib/requirejs.php');
1373         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1374
1375         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1376
1377         // No extension required unless slash args is disabled.
1378         $jsextension = '.js';
1379         if (!empty($CFG->slasharguments)) {
1380             $jsextension = '';
1381         }
1382
1383         $minextension = '.min';
1384         if (!$cachejs) {
1385             $minextension = '';
1386         }
1387
1388         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1389         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1390         $requirejsconfig = str_replace('[JSMIN]', $minextension, $requirejsconfig);
1391         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1392
1393         $output .= html_writer::script($requirejsconfig);
1394         if ($cachejs) {
1395             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1396         } else {
1397             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1398         }
1399
1400         // First include must be to a module with no dependencies, this prevents multiple requests.
1401         $prefix = <<<EOF
1402 M.util.js_pending("core/first");
1403 require(['core/first'], function() {
1404
1405 EOF;
1406
1407         if (during_initial_install()) {
1408             // Do not run a prefetch during initial install as the DB is not available to service WS calls.
1409             $prefetch = '';
1410         } else {
1411             $prefetch = "require(['core/prefetch'])\n";
1412         }
1413
1414         $suffix = <<<EOF
1415
1416     M.util.js_complete("core/first");
1417 });
1418 EOF;
1419
1420         $output .= html_writer::script($prefix . $prefetch . implode(";\n", $this->amdjscode) . $suffix);
1421         return $output;
1422     }
1423
1424     /**
1425      * Returns basic YUI3 CSS code.
1426      *
1427      * @return string
1428      */
1429     protected function get_yui3lib_headcss() {
1430         global $CFG;
1431
1432         $yuiformat = '-min';
1433         if ($this->yui3loader->filter === 'RAW') {
1434             $yuiformat = '';
1435         }
1436
1437         $code = '';
1438         if ($this->yui3loader->combine) {
1439             if (!empty($this->yuicssmodules)) {
1440                 $modules = array();
1441                 foreach ($this->yuicssmodules as $module) {
1442                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1443                 }
1444                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1445             }
1446             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1447
1448         } else {
1449             if (!empty($this->yuicssmodules)) {
1450                 foreach ($this->yuicssmodules as $module) {
1451                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1452                 }
1453             }
1454             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1455         }
1456
1457         if ($this->yui3loader->filter === 'RAW') {
1458             $code = str_replace('-min.css', '.css', $code);
1459         } else if ($this->yui3loader->filter === 'DEBUG') {
1460             $code = str_replace('-min.css', '.css', $code);
1461         }
1462         return $code;
1463     }
1464
1465     /**
1466      * Returns basic YUI3 JS loading code.
1467      *
1468      * @return string
1469      */
1470     protected function get_yui3lib_headcode() {
1471         global $CFG;
1472
1473         $jsrev = $this->get_jsrev();
1474
1475         $yuiformat = '-min';
1476         if ($this->yui3loader->filter === 'RAW') {
1477             $yuiformat = '';
1478         }
1479
1480         $format = '-min';
1481         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1482             $format = '-debug';
1483         }
1484
1485         $rollupversion = $CFG->yui3version;
1486         if (!empty($CFG->yuipatchlevel)) {
1487             $rollupversion .= '_' . $CFG->yuipatchlevel;
1488         }
1489
1490         $baserollups = array(
1491             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1492         );
1493
1494         if ($this->yui3loader->combine) {
1495             return '<script src="' .
1496                     $this->yui3loader->local_comboBase .
1497                     implode('&amp;', $baserollups) .
1498                     '"></script>';
1499         } else {
1500             $code = '';
1501             foreach ($baserollups as $rollup) {
1502                 $code .= '<script src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1503             }
1504             return $code;
1505         }
1506
1507     }
1508
1509     /**
1510      * Returns html tags needed for inclusion of theme CSS.
1511      *
1512      * @return string
1513      */
1514     protected function get_css_code() {
1515         // First of all the theme CSS, then any custom CSS
1516         // Please note custom CSS is strongly discouraged,
1517         // because it can not be overridden by themes!
1518         // It is suitable only for things like mod/data which accepts CSS from teachers.
1519         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1520
1521         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1522         $code = $this->get_yui3lib_headcss();
1523
1524         // This line of code may look funny but it is currently required in order
1525         // to avoid MASSIVE display issues in Internet Explorer.
1526         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1527         // ignored whenever another resource is added until such time as a redraw
1528         // is forced, usually by moving the mouse over the affected element.
1529         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1530
1531         $urls = $this->cssthemeurls + $this->cssurls;
1532         foreach ($urls as $url) {
1533             $attributes['href'] = $url;
1534             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1535             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1536             unset($attributes['id']);
1537         }
1538
1539         return $code;
1540     }
1541
1542     /**
1543      * Adds extra modules specified after printing of page header.
1544      *
1545      * @return string
1546      */
1547     protected function get_extra_modules_code() {
1548         if (empty($this->extramodules)) {
1549             return '';
1550         }
1551         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1552     }
1553
1554     /**
1555      * Generate any HTML that needs to go inside the <head> tag.
1556      *
1557      * Normally, this method is called automatically by the code that prints the
1558      * <head> tag. You should not normally need to call it in your own code.
1559      *
1560      * @param moodle_page $page
1561      * @param core_renderer $renderer
1562      * @return string the HTML code to to inside the <head> tag.
1563      */
1564     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1565         global $CFG;
1566
1567         // Note: the $page and $output are not stored here because it would
1568         // create circular references in memory which prevents garbage collection.
1569         $this->init_requirements_data($page, $renderer);
1570
1571         $output = '';
1572
1573         // Add all standard CSS for this page.
1574         $output .= $this->get_css_code();
1575
1576         // Set up the M namespace.
1577         $js = "var M = {}; M.yui = {};\n";
1578
1579         // Capture the time now ASAP during page load. This minimises the lag when
1580         // we try to relate times on the server to times in the browser.
1581         // An example of where this is used is the quiz countdown timer.
1582         $js .= "M.pageloadstarttime = new Date();\n";
1583
1584         // Add a subset of Moodle configuration to the M namespace.
1585         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1586
1587         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1588         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1589         //       this needs to be done before including any other script.
1590         $js .= $this->YUI_config->get_config_functions();
1591         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1592         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1593         $js = $this->YUI_config->update_header_js($js);
1594
1595         $output .= html_writer::script($js);
1596
1597         // Add variables.
1598         if ($this->jsinitvariables['head']) {
1599             $js = '';
1600             foreach ($this->jsinitvariables['head'] as $data) {
1601                 list($var, $value) = $data;
1602                 $js .= js_writer::set_variable($var, $value, true);
1603             }
1604             $output .= html_writer::script($js);
1605         }
1606
1607         // Mark head sending done, it is not possible to anything there.
1608         $this->headdone = true;
1609
1610         return $output;
1611     }
1612
1613     /**
1614      * Generate any HTML that needs to go at the start of the <body> tag.
1615      *
1616      * Normally, this method is called automatically by the code that prints the
1617      * <head> tag. You should not normally need to call it in your own code.
1618      *
1619      * @param renderer_base $renderer
1620      * @return string the HTML code to go at the start of the <body> tag.
1621      */
1622     public function get_top_of_body_code(renderer_base $renderer) {
1623         global $CFG;
1624
1625         // First the skip links.
1626         $output = $renderer->render_skip_links($this->skiplinks);
1627
1628         // Include the Polyfills.
1629         $output .= html_writer::script('', $this->js_fix_url('/lib/polyfills/polyfill.js'));
1630
1631         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1632         $output .= $this->get_yui3lib_headcode();
1633
1634         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1635         $output .= $this->get_jquery_headcode();
1636
1637         // Link our main JS file, all core stuff should be there.
1638         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1639
1640         // All the other linked things from HEAD - there should be as few as possible.
1641         if ($this->jsincludes['head']) {
1642             foreach ($this->jsincludes['head'] as $url) {
1643                 $output .= html_writer::script('', $url);
1644             }
1645         }
1646
1647         // Then the clever trick for hiding of things not needed when JS works.
1648         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1649         $this->topofbodydone = true;
1650         return $output;
1651     }
1652
1653     /**
1654      * Generate any HTML that needs to go at the end of the page.
1655      *
1656      * Normally, this method is called automatically by the code that prints the
1657      * page footer. You should not normally need to call it in your own code.
1658      *
1659      * @return string the HTML code to to at the end of the page.
1660      */
1661     public function get_end_code() {
1662         global $CFG;
1663         $output = '';
1664
1665         // Set the log level for the JS logging.
1666         $logconfig = new stdClass();
1667         $logconfig->level = 'warn';
1668         if ($CFG->debugdeveloper) {
1669             $logconfig->level = 'trace';
1670         }
1671         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1672         // Add any global JS that needs to run on all pages.
1673         $this->js_call_amd('core/page_global', 'init');
1674         $this->js_call_amd('core/utility');
1675
1676         // Call amd init functions.
1677         $output .= $this->get_amd_footercode();
1678
1679         // Add other requested modules.
1680         $output .= $this->get_extra_modules_code();
1681
1682         $this->js_init_code('M.util.js_complete("init");', true);
1683
1684         // All the other linked scripts - there should be as few as possible.
1685         if ($this->jsincludes['footer']) {
1686             foreach ($this->jsincludes['footer'] as $url) {
1687                 $output .= html_writer::script('', $url);
1688             }
1689         }
1690
1691         // Add all needed strings.
1692         // First add core strings required for some dialogues.
1693         $this->strings_for_js(array(
1694             'confirm',
1695             'yes',
1696             'no',
1697             'areyousure',
1698             'closebuttontitle',
1699             'unknownerror',
1700             'error',
1701             'file',
1702             'url',
1703             // TODO MDL-70830 shortforms should preload the collapseall/expandall strings properly.
1704             'collapseall',
1705             'expandall',
1706         ), 'moodle');
1707         $this->strings_for_js(array(
1708             'debuginfo',
1709             'line',
1710             'stacktrace',
1711         ), 'debug');
1712         $this->string_for_js('labelsep', 'langconfig');
1713         if (!empty($this->stringsforjs)) {
1714             $strings = array();
1715             foreach ($this->stringsforjs as $component=>$v) {
1716                 foreach($v as $indentifier => $langstring) {
1717                     $strings[$component][$indentifier] = $langstring->out();
1718                 }
1719             }
1720             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1721         }
1722
1723         // Add variables.
1724         if ($this->jsinitvariables['footer']) {
1725             $js = '';
1726             foreach ($this->jsinitvariables['footer'] as $data) {
1727                 list($var, $value) = $data;
1728                 $js .= js_writer::set_variable($var, $value, true);
1729             }
1730             $output .= html_writer::script($js);
1731         }
1732
1733         $inyuijs = $this->get_javascript_code(false);
1734         $ondomreadyjs = $this->get_javascript_code(true);
1735         $jsinit = $this->get_javascript_init_code();
1736         $handlersjs = $this->get_event_handler_code();
1737
1738         // There is a global Y, make sure it is available in your scope.
1739         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1740
1741         $output .= html_writer::script($js);
1742
1743         return $output;
1744     }
1745
1746     /**
1747      * Have we already output the code in the <head> tag?
1748      *
1749      * @return bool
1750      */
1751     public function is_head_done() {
1752         return $this->headdone;
1753     }
1754
1755     /**
1756      * Have we already output the code at the start of the <body> tag?
1757      *
1758      * @return bool
1759      */
1760     public function is_top_of_body_done() {
1761         return $this->topofbodydone;
1762     }
1763
1764     /**
1765      * Should we generate a bit of content HTML that is only required once  on
1766      * this page (e.g. the contents of the modchooser), now? Basically, we call
1767      * {@link has_one_time_item_been_created()}, and if the thing has not already
1768      * been output, we return true to tell the caller to generate it, and also
1769      * call {@link set_one_time_item_created()} to record the fact that it is
1770      * about to be generated.
1771      *
1772      * That is, a typical usage pattern (in a renderer method) is:
1773      * <pre>
1774      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1775      *     return '';
1776      * }
1777      * // Else generate it.
1778      * </pre>
1779      *
1780      * @param string $thing identifier for the bit of content. Should be of the form
1781      *      frankenstyle_things, e.g. core_course_modchooser.
1782      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1783      */
1784     public function should_create_one_time_item_now($thing) {
1785         if ($this->has_one_time_item_been_created($thing)) {
1786             return false;
1787         }
1788
1789         $this->set_one_time_item_created($thing);
1790         return true;
1791     }
1792
1793     /**
1794      * Has a particular bit of HTML that is only required once  on this page
1795      * (e.g. the contents of the modchooser) already been generated?
1796      *
1797      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1798      * method rather than calling this method directly.
1799      *
1800      * @param string $thing identifier for the bit of content. Should be of the form
1801      *      frankenstyle_things, e.g. core_course_modchooser.
1802      * @return bool whether that bit of output has been created.
1803      */
1804     public function has_one_time_item_been_created($thing) {
1805         return isset($this->onetimeitemsoutput[$thing]);
1806     }
1807
1808     /**
1809      * Indicate that a particular bit of HTML that is only required once on this
1810      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1811      *
1812      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1813      * method rather than calling this method directly.
1814      *
1815      * @param string $thing identifier for the bit of content. Should be of the form
1816      *      frankenstyle_things, e.g. core_course_modchooser.
1817      */
1818     public function set_one_time_item_created($thing) {
1819         if ($this->has_one_time_item_been_created($thing)) {
1820             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1821                     'once per page, but it seems to be being output again.');
1822         }
1823         return $this->onetimeitemsoutput[$thing] = true;
1824     }
1825 }
1826
1827 /**
1828  * This class represents the YUI configuration.
1829  *
1830  * @copyright 2013 Andrew Nicols
1831  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1832  * @since Moodle 2.5
1833  * @package core
1834  * @category output
1835  */
1836 class YUI_config {
1837     /**
1838      * These settings must be public so that when the object is converted to json they are exposed.
1839      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1840      *
1841      * The settings are described and documented in the YUI API at:
1842      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1843      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1844      */
1845     public $debug = false;
1846     public $base;
1847     public $comboBase;
1848     public $combine;
1849     public $filter = null;
1850     public $insertBefore = 'firstthemesheet';
1851     public $groups = array();
1852     public $modules = array();
1853     /** @var array The log sources that should be not be logged. */
1854     public $logInclude = [];
1855     /** @var array Tog sources that should be logged. */
1856     public $logExclude = [];
1857     /** @var string The minimum log level for YUI logging statements. */
1858     public $logLevel;
1859
1860     /**
1861      * @var array List of functions used by the YUI Loader group pattern recognition.
1862      */
1863     protected $jsconfigfunctions = array();
1864
1865     /**
1866      * Create a new group within the YUI_config system.
1867      *
1868      * @param String $name The name of the group. This must be unique and
1869      * not previously used.
1870      * @param Array $config The configuration for this group.
1871      * @return void
1872      */
1873     public function add_group($name, $config) {
1874         if (isset($this->groups[$name])) {
1875             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1876         }
1877         $this->groups[$name] = $config;
1878     }
1879
1880     /**
1881      * Update an existing group configuration
1882      *
1883      * Note, any existing configuration for that group will be wiped out.
1884      * This includes module configuration.
1885      *
1886      * @param String $name The name of the group. This must be unique and
1887      * not previously used.
1888      * @param Array $config The configuration for this group.
1889      * @return void
1890      */
1891     public function update_group($name, $config) {
1892         if (!isset($this->groups[$name])) {
1893             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.');
1894         }
1895         $this->groups[$name] = $config;
1896     }
1897
1898     /**
1899      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1900      *
1901      * Only the body of the function should be passed, and not the whole function wrapper.
1902      *
1903      * The JS function your write will be passed a single argument 'name' containing the
1904      * name of the module being loaded.
1905      *
1906      * @param $function String the body of the JavaScript function. This should be used i
1907      * @return String the name of the function to use in the group pattern configuration.
1908      */
1909     public function set_config_function($function) {
1910         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1911         if (isset($this->jsconfigfunctions[$configname])) {
1912             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1913         }
1914         $this->jsconfigfunctions[$configname] = $function;
1915         return '@' . $configname . '@';
1916     }
1917
1918     /**
1919      * Allow setting of the config function described in {@see set_config_function} from a file.
1920      * The contents of this file are then passed to set_config_function.
1921      *
1922      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1923      *
1924      * @param $file The path to the JavaScript function used for YUI configuration.
1925      * @return String the name of the function to use in the group pattern configuration.
1926      */
1927     public function set_config_source($file) {
1928         global $CFG;
1929         $cache = cache::make('core', 'yuimodules');
1930
1931         // Attempt to get the metadata from the cache.
1932         $keyname = 'configfn_' . $file;
1933         $fullpath = $CFG->dirroot . '/' . $file;
1934         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1935             $cache->delete($keyname);
1936             $configfn = file_get_contents($fullpath);
1937         } else {
1938             $configfn = $cache->get($keyname);
1939             if ($configfn === false) {
1940                 require_once($CFG->libdir . '/jslib.php');
1941                 $configfn = core_minify::js_files(array($fullpath));
1942                 $cache->set($keyname, $configfn);
1943             }
1944         }
1945         return $this->set_config_function($configfn);
1946     }
1947
1948     /**
1949      * Retrieve the list of JavaScript functions for YUI_config groups.
1950      *
1951      * @return String The complete set of config functions
1952      */
1953     public function get_config_functions() {
1954         $configfunctions = '';
1955         foreach ($this->jsconfigfunctions as $functionname => $function) {
1956             $configfunctions .= "var {$functionname} = function(me) {";
1957             $configfunctions .= $function;
1958             $configfunctions .= "};\n";
1959         }
1960         return $configfunctions;
1961     }
1962
1963     /**
1964      * Update the header JavaScript with any required modification for the YUI Loader.
1965      *
1966      * @param $js String The JavaScript to manipulate.
1967      * @return String the modified JS string.
1968      */
1969     public function update_header_js($js) {
1970         // Update the names of the the configFn variables.
1971         // The PHP json_encode function cannot handle literal names so we have to wrap
1972         // them in @ and then replace them with literals of the same function name.
1973         foreach ($this->jsconfigfunctions as $functionname => $function) {
1974             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1975         }
1976         return $js;
1977     }
1978
1979     /**
1980      * Add configuration for a specific module.
1981      *
1982      * @param String $name The name of the module to add configuration for.
1983      * @param Array $config The configuration for the specified module.
1984      * @param String $group The name of the group to add configuration for.
1985      * If not specified, then this module is added to the global
1986      * configuration.
1987      * @return void
1988      */
1989     public function add_module_config($name, $config, $group = null) {
1990         if ($group) {
1991             if (!isset($this->groups[$name])) {
1992                 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.');
1993             }
1994             if (!isset($this->groups[$group]['modules'])) {
1995                 $this->groups[$group]['modules'] = array();
1996             }
1997             $modules = &$this->groups[$group]['modules'];
1998         } else {
1999             $modules = &$this->modules;
2000         }
2001         $modules[$name] = $config;
2002     }
2003
2004     /**
2005      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
2006      *
2007      * If js caching is disabled, metadata will not be served causing YUI to calculate
2008      * module dependencies as each module is loaded.
2009      *
2010      * If metadata does not exist it will be created and stored in a MUC entry.
2011      *
2012      * @return void
2013      */
2014     public function add_moodle_metadata() {
2015         global $CFG;
2016         if (!isset($this->groups['moodle'])) {
2017             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.');
2018         }
2019
2020         if (!isset($this->groups['moodle']['modules'])) {
2021             $this->groups['moodle']['modules'] = array();
2022         }
2023
2024         $cache = cache::make('core', 'yuimodules');
2025         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
2026             $metadata = array();
2027             $metadata = $this->get_moodle_metadata();
2028             $cache->delete('metadata');
2029         } else {
2030             // Attempt to get the metadata from the cache.
2031             if (!$metadata = $cache->get('metadata')) {
2032                 $metadata = $this->get_moodle_metadata();
2033                 $cache->set('metadata', $metadata);
2034             }
2035         }
2036
2037         // Merge with any metadata added specific to this page which was added manually.
2038         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
2039                 $metadata);
2040     }
2041
2042     /**
2043      * Determine the module metadata for all moodle YUI modules.
2044      *
2045      * This works through all modules capable of serving YUI modules, and attempts to get
2046      * metadata for each of those modules.
2047      *
2048      * @return Array of module metadata
2049      */
2050     private function get_moodle_metadata() {
2051         $moodlemodules = array();
2052         // Core isn't a plugin type or subsystem - handle it seperately.
2053         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
2054             $moodlemodules = array_merge($moodlemodules, $module);
2055         }
2056
2057         // Handle other core subsystems.
2058         $subsystems = core_component::get_core_subsystems();
2059         foreach ($subsystems as $subsystem => $path) {
2060             if (is_null($path)) {
2061                 continue;
2062             }
2063             if ($module = $this->get_moodle_path_metadata($path)) {
2064                 $moodlemodules = array_merge($moodlemodules, $module);
2065             }
2066         }
2067
2068         // And finally the plugins.
2069         $plugintypes = core_component::get_plugin_types();
2070         foreach ($plugintypes as $plugintype => $pathroot) {
2071             $pluginlist = core_component::get_plugin_list($plugintype);
2072             foreach ($pluginlist as $plugin => $path) {
2073                 if ($module = $this->get_moodle_path_metadata($path)) {
2074                     $moodlemodules = array_merge($moodlemodules, $module);
2075                 }
2076             }
2077         }
2078
2079         return $moodlemodules;
2080     }
2081
2082     /**
2083      * Helper function process and return the YUI metadata for all of the modules under the specified path.
2084      *
2085      * @param String $path the UNC path to the YUI src directory.
2086      * @return Array the complete array for frankenstyle directory.
2087      */
2088     private function get_moodle_path_metadata($path) {
2089         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
2090         $baseyui = $path . '/yui/src';
2091         $modules = array();
2092         if (is_dir($baseyui)) {
2093             $items = new DirectoryIterator($baseyui);
2094             foreach ($items as $item) {
2095                 if ($item->isDot() or !$item->isDir()) {
2096                     continue;
2097                 }
2098                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
2099                 if (!is_readable($metafile)) {
2100                     continue;
2101                 }
2102                 $metadata = file_get_contents($metafile);
2103                 $modules = array_merge($modules, (array) json_decode($metadata));
2104             }
2105         }
2106         return $modules;
2107     }
2108
2109     /**
2110      * Define YUI modules which we have been required to patch between releases.
2111      *
2112      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2113      * external CDN which will serve the true authoritative copy of the code without our patches.
2114      *
2115      * @param String combobase The local combobase
2116      * @param String yuiversion The current YUI version
2117      * @param Int patchlevel The patch level we're working to for YUI
2118      * @param Array patchedmodules An array containing the names of the patched modules
2119      * @return void
2120      */
2121     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2122         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2123         $subversion = $yuiversion . '_' . $patchlevel;
2124
2125         if ($this->comboBase == $combobase) {
2126             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2127             // loader. We just need to specify a different root which includes a slightly different YUI version number
2128             // to include our patchlevel.
2129             $patterns = array();
2130             $modules = array();
2131             foreach ($patchedmodules as $modulename) {
2132                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2133                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2134                 // loaded when the module is loaded anyway.
2135                 $patterns[$modulename] = array(
2136                     'group' => 'yui-patched',
2137                 );
2138                 $modules[$modulename] = array();
2139             }
2140
2141             // Actually add the patch group here.
2142             $this->add_group('yui-patched', array(
2143                 'combine' => true,
2144                 'root' => $subversion . '/',
2145                 'patterns' => $patterns,
2146                 'modules' => $modules,
2147             ));
2148
2149         } else {
2150             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2151             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2152             // local base in browser caches.
2153             $fullpathbase = $combobase . $subversion . '/';
2154             foreach ($patchedmodules as $modulename) {
2155                 $this->modules[$modulename] = array(
2156                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2157                 );
2158             }
2159         }
2160     }
2161 }
2162
2163 /**
2164  * Invalidate all server and client side template caches.
2165  */
2166 function template_reset_all_caches() {
2167     global $CFG;
2168
2169     $next = time();
2170     if (isset($CFG->templaterev) and $next <= $CFG->templaterev and $CFG->templaterev - $next < 60 * 60) {
2171         // This resolves problems when reset is requested repeatedly within 1s,
2172         // the < 1h condition prevents accidental switching to future dates
2173         // because we might not recover from it.
2174         $next = $CFG->templaterev + 1;
2175     }
2176
2177     set_config('templaterev', $next);
2178 }
2179
2180 /**
2181  * Invalidate all server and client side JS caches.
2182  */
2183 function js_reset_all_caches() {
2184     global $CFG;
2185
2186     $next = time();
2187     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2188         // This resolves problems when reset is requested repeatedly within 1s,
2189         // the < 1h condition prevents accidental switching to future dates
2190         // because we might not recover from it.
2191         $next = $CFG->jsrev+1;
2192     }
2193
2194     set_config('jsrev', $next);
2195 }