lib/outputrequirementslib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Library functions to facilitate the use of JavaScript in Moodle.
  19  *
  20  * Note: you can find history of this file in lib/ajax/ajaxlib.php
  21  *
  22  * @copyright 2009 Tim Hunt, 2010 Petr Skoda
  23  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  * @package core
  25  * @category output
  26  */
  27
  28 defined('MOODLE_INTERNAL') || die();
  29
  30 /**
  31  * This class tracks all the things that are needed by the current page.
  32  *
  33  * Normally, the only instance of this  class you will need to work with is the
  34  * one accessible via $PAGE->requires.
  35  *
  36  * Typical usage would be
  37  * <pre>
  38  *     $PAGE->requires->js_call_amd('mod_forum/view', 'init');
  39  * </pre>
  40  *
  41  * It also supports obsoleted coding style with/without YUI3 modules.
  42  * <pre>
  43  *     $PAGE->requires->js_init_call('M.mod_forum.init_view');
  44  *     $PAGE->requires->css('/mod/mymod/userstyles.php?id='.$id); // not overridable via themes!
  45  *     $PAGE->requires->js('/mod/mymod/script.js');
  46  *     $PAGE->requires->js('/mod/mymod/small_but_urgent.js', true);
  47  *     $PAGE->requires->js_function_call('init_mymod', array($data), true);
  48  * </pre>
  49  *
  50  * There are some natural restrictions on some methods. For example, {@link css()}
  51  * can only be called before the <head> tag is output. See the comments on the
  52  * individual methods for details.
  53  *
  54  * @copyright 2009 Tim Hunt, 2010 Petr Skoda
  55  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  56  * @since Moodle 2.0
  57  * @package core
  58  * @category output
  59  */
  60 class page_requirements_manager {
  61
  62     /**
  63      * @var array List of string available from JS
  64      */
  65     protected $stringsforjs = array();
  66
  67     /**
  68      * @var array List of get_string $a parameters - used for validation only.
  69      */
  70     protected $stringsforjs_as = array();
  71
  72     /**
  73      * @var array List of JS variables to be initialised
  74      */
  75     protected $jsinitvariables = array('head'=>array(), 'footer'=>array());
  76
  77     /**
  78      * @var array Included JS scripts
  79      */
  80     protected $jsincludes = array('head'=>array(), 'footer'=>array());
  81
  82     /**
  83      * @var array Inline scripts using RequireJS module loading.
  84      */
  85     protected $amdjscode = array('');
  86
  87     /**
  88      * @var array List of needed function calls
  89      */
  90     protected $jscalls = array('normal'=>array(), 'ondomready'=>array());
  91
  92     /**
  93      * @var array List of skip links, those are needed for accessibility reasons
  94      */
  95     protected $skiplinks = array();
  96
  97     /**
  98      * @var array Javascript code used for initialisation of page, it should
  99      * be relatively small
 100      */
 101     protected $jsinitcode = array();
 102
 103     /**
 104      * @var array of moodle_url Theme sheets, initialised only from core_renderer
 105      */
 106     protected $cssthemeurls = array();
 107
 108     /**
 109      * @var array of moodle_url List of custom theme sheets, these are strongly discouraged!
 110      * Useful mostly only for CSS submitted by teachers that is not part of the theme.
 111      */
 112     protected $cssurls = array();
 113
 114     /**
 115      * @var array List of requested event handlers
 116      */
 117     protected $eventhandlers = array();
 118
 119     /**
 120      * @var array Extra modules
 121      */
 122     protected $extramodules = array();
 123
 124     /**
 125      * @var array trackes the names of bits of HTML that are only required once
 126      * per page. See {@link has_one_time_item_been_created()},
 127      * {@link set_one_time_item_created()} and {@link should_create_one_time_item_now()}.
 128      */
 129     protected $onetimeitemsoutput = array();
 130
 131     /**
 132      * @var bool Flag indicated head stuff already printed
 133      */
 134     protected $headdone = false;
 135
 136     /**
 137      * @var bool Flag indicating top of body already printed
 138      */
 139     protected $topofbodydone = false;
 140
 141     /**
 142      * @var stdClass YUI PHPLoader instance responsible for YUI3 loading from PHP only
 143      */
 144     protected $yui3loader;
 145
 146     /**
 147      * @var YUI_config default YUI loader configuration
 148      */
 149     protected $YUI_config;
 150
 151     /**
 152      * @var array $yuicssmodules
 153      */
 154     protected $yuicssmodules = array();
 155
 156     /**
 157      * @var array Some config vars exposed in JS, please no secret stuff there
 158      */
 159     protected $M_cfg;
 160
 161     /**
 162      * @var array list of requested jQuery plugins
 163      */
 164     protected $jqueryplugins = array();
 165
 166     /**
 167      * @var array list of jQuery plugin overrides
 168      */
 169     protected $jquerypluginoverrides = array();
 170
 171     /**
 172      * Page requirements constructor.
 173      */
 174     public function __construct() {
 175         global $CFG;
 176
 177         // You may need to set up URL rewrite rule because oversized URLs might not be allowed by web server.
 178         $sep = empty($CFG->yuislasharguments) ? '?' : '/';
 179
 180         $this->yui3loader = new stdClass();
 181         $this->YUI_config = new YUI_config();
 182
 183         if (is_https() && !empty($CFG->useexternalyui)) {
 184             // On HTTPS sites all JS must be loaded from https sites,
 185             // YUI CDN does not support https yet, sorry.
 186             $CFG->useexternalyui = 0;
 187         }
 188
 189         // Set up some loader options.
 190         $this->yui3loader->local_base = $CFG->wwwroot . '/lib/yuilib/'. $CFG->yui3version . '/';
 191         $this->yui3loader->local_comboBase = $CFG->wwwroot . '/theme/yui_combo.php'.$sep;
 192
 193         if (!empty($CFG->useexternalyui)) {
 194             $this->yui3loader->base = 'http://yui.yahooapis.com/' . $CFG->yui3version . '/';
 195             $this->yui3loader->comboBase = 'http://yui.yahooapis.com/combo?';
 196         } else {
 197             $this->yui3loader->base = $this->yui3loader->local_base;
 198             $this->yui3loader->comboBase = $this->yui3loader->local_comboBase;
 199         }
 200
 201         // Enable combo loader? This significantly helps with caching and performance!
 202         $this->yui3loader->combine = !empty($CFG->yuicomboloading);
 203
 204         $jsrev = $this->get_jsrev();
 205
 206         // Set up JS YUI loader helper object.
 207         $this->YUI_config->base         = $this->yui3loader->base;
 208         $this->YUI_config->comboBase    = $this->yui3loader->comboBase;
 209         $this->YUI_config->combine      = $this->yui3loader->combine;
 210
 211         // If we've had to patch any YUI modules between releases, we must override the YUI configuration to include them.
 212         // For important information on patching YUI modules, please see http://docs.moodle.org/dev/YUI/Patching.
 213         if (!empty($CFG->yuipatchedmodules) && !empty($CFG->yuipatchlevel)) {
 214             $this->YUI_config->define_patched_core_modules($this->yui3loader->local_comboBase,
 215                     $CFG->yui3version,
 216                     $CFG->yuipatchlevel,
 217                     $CFG->yuipatchedmodules);
 218         }
 219
 220         $configname = $this->YUI_config->set_config_source('lib/yui/config/yui2.js');
 221         $this->YUI_config->add_group('yui2', array(
 222             // Loader configuration for our 2in3, for now ignores $CFG->useexternalyui.
 223             'base' => $CFG->wwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 224             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 225             'combine' => $this->yui3loader->combine,
 226             'ext' => false,
 227             'root' => '2in3/' . $CFG->yui2version .'/build/',
 228             'patterns' => array(
 229                 'yui2-' => array(
 230                     'group' => 'yui2',
 231                     'configFn' => $configname,
 232                 )
 233             )
 234         ));
 235         $configname = $this->YUI_config->set_config_source('lib/yui/config/moodle.js');
 236         $this->YUI_config->add_group('moodle', array(
 237             'name' => 'moodle',
 238             'base' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep . 'm/' . $jsrev . '/',
 239             'combine' => $this->yui3loader->combine,
 240             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php'.$sep,
 241             'ext' => false,
 242             'root' => 'm/'.$jsrev.'/', // Add the rev to the root path so that we can control caching.
 243             'patterns' => array(
 244                 'moodle-' => array(
 245                     'group' => 'moodle',
 246                     'configFn' => $configname,
 247                 )
 248             )
 249         ));
 250
 251         $this->YUI_config->add_group('gallery', array(
 252             'name' => 'gallery',
 253             'base' => $CFG->wwwroot . '/lib/yuilib/gallery/',
 254             'combine' => $this->yui3loader->combine,
 255             'comboBase' => $CFG->wwwroot . '/theme/yui_combo.php' . $sep,
 256             'ext' => false,
 257             'root' => 'gallery/' . $jsrev . '/',
 258             'patterns' => array(
 259                 'gallery-' => array(
 260                     'group' => 'gallery',
 261                 )
 262             )
 263         ));
 264
 265         // Set some more loader options applying to groups too.
 266         if ($CFG->debugdeveloper) {
 267             // When debugging is enabled, we want to load the non-minified (RAW) versions of YUI library modules rather
 268             // than the DEBUG versions as these generally generate too much logging for our purposes.
 269             // However we do want the DEBUG versions of our Moodle-specific modules.
 270             // To debug a YUI-specific issue, change the yui3loader->filter value to DEBUG.
 271             $this->YUI_config->filter = 'RAW';
 272             $this->YUI_config->groups['moodle']['filter'] = 'DEBUG';
 273
 274             // We use the yui3loader->filter setting when writing the YUI3 seed scripts into the header.
 275             $this->yui3loader->filter = $this->YUI_config->filter;
 276             $this->YUI_config->debug = true;
 277         } else {
 278             $this->yui3loader->filter = null;
 279             $this->YUI_config->groups['moodle']['filter'] = null;
 280             $this->YUI_config->debug = false;
 281         }
 282
 283         // Include the YUI config log filters.
 284         if (!empty($CFG->yuilogexclude) && is_array($CFG->yuilogexclude)) {
 285             $this->YUI_config->logExclude = $CFG->yuilogexclude;
 286         }
 287         if (!empty($CFG->yuiloginclude) && is_array($CFG->yuiloginclude)) {
 288             $this->YUI_config->logInclude = $CFG->yuiloginclude;
 289         }
 290         if (!empty($CFG->yuiloglevel)) {
 291             $this->YUI_config->logLevel = $CFG->yuiloglevel;
 292         }
 293
 294         // Add the moodle group's module data.
 295         $this->YUI_config->add_moodle_metadata();
 296
 297         // Every page should include definition of following modules.
 298         $this->js_module($this->find_module('core_filepicker'));
 299         $this->js_module($this->find_module('core_comment'));
 300     }
 301
 302     /**
 303      * Return the safe config values that get set for javascript in "M.cfg".
 304      *
 305      * @since 2.9
 306      * @return array List of safe config values that are available to javascript.
 307      */
 308     public function get_config_for_javascript(moodle_page $page, renderer_base $renderer) {
 309         global $CFG;
 310
 311         if (empty($this->M_cfg)) {
 312
 313             $iconsystem = \core\output\icon_system::instance();
 314
 315             // It is possible that the $page->context is null, so we can't use $page->context->id.
 316             $contextid = null;
 317             $contextinstanceid = null;
 318             if (!is_null($page->context)) {
 319                 $contextid = $page->context->id;
 320                 $contextinstanceid = $page->context->instanceid;
 321                 $courseid = $page->course->id;
 322                 $coursecontext = context_course::instance($courseid);
 323             }
 324
 325             $this->M_cfg = array(
 326                 'wwwroot'               => $CFG->wwwroot,
 327                 'homeurl'               => $page->navigation->action,
 328                 'sesskey'               => sesskey(),
 329                 'sessiontimeout'        => $CFG->sessiontimeout,
 330                 'sessiontimeoutwarning' => $CFG->sessiontimeoutwarning,
 331                 'themerev'              => theme_get_revision(),
 332                 'slasharguments'        => (int)(!empty($CFG->slasharguments)),
 333                 'theme'                 => $page->theme->name,
 334                 'iconsystemmodule'      => $iconsystem->get_amd_name(),
 335                 'jsrev'                 => $this->get_jsrev(),
 336                 'admin'                 => $CFG->admin,
 337                 'svgicons'              => $page->theme->use_svg_icons(),
 338                 'usertimezone'          => usertimezone(),
 339                 'courseId'              => isset($courseid) ? (int) $courseid : 0,
 340                 'courseContextId'       => isset($coursecontext) ? $coursecontext->id : 0,
 341                 'contextid'             => $contextid,
 342                 'contextInstanceId'     => (int) $contextinstanceid,
 343                 'langrev'               => get_string_manager()->get_revision(),
 344                 'templaterev'           => $this->get_templaterev()
 345             );
 346             if ($CFG->debugdeveloper) {
 347                 $this->M_cfg['developerdebug'] = true;
 348             }
 349             if (defined('BEHAT_SITE_RUNNING')) {
 350                 $this->M_cfg['behatsiterunning'] = true;
 351             }
 352
 353         }
 354         return $this->M_cfg;
 355     }
 356
 357     /**
 358      * Initialise with the bits of JavaScript that every Moodle page should have.
 359      *
 360      * @param moodle_page $page
 361      * @param core_renderer $renderer
 362      */
 363     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 364         global $CFG;
 365
 366         // Init the js config.
 367         $this->get_config_for_javascript($page, $renderer);
 368
 369         // Accessibility stuff.
 370         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 371
 372         // Add strings used on many pages.
 373         $this->string_for_js('confirmation', 'admin');
 374         $this->string_for_js('cancel', 'moodle');
 375         $this->string_for_js('yes', 'moodle');
 376
 377         // Alter links in top frame to break out of frames.
 378         if ($page->pagelayout === 'frametop') {
 379             $this->js_init_call('M.util.init_frametop');
 380         }
 381
 382         // Include block drag/drop if editing is on
 383         if ($page->user_is_editing()) {
 384             $params = array(
 385                 'courseid' => $page->course->id,
 386                 'pagetype' => $page->pagetype,
 387                 'pagelayout' => $page->pagelayout,
 388                 'subpage' => $page->subpage,
 389                 'regions' => $page->blocks->get_regions(),
 390                 'contextid' => $page->context->id,
 391             );
 392             if (!empty($page->cm->id)) {
 393                 $params['cmid'] = $page->cm->id;
 394             }
 395             // Strings for drag and drop.
 396             $this->strings_for_js(array('movecontent',
 397                                         'tocontent',
 398                                         'emptydragdropregion'),
 399                                   'moodle');
 400             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 401         }
 402
 403         // Include the YUI CSS Modules.
 404         $page->requires->set_yuicssmodules($page->theme->yuicssmodules);
 405     }
 406
 407     /**
 408      * Determine the correct JS Revision to use for this load.
 409      *
 410      * @return int the jsrev to use.
 411      */
 412     public function get_jsrev() {
 413         global $CFG;
 414
 415         if (empty($CFG->cachejs)) {
 416             $jsrev = -1;
 417         } else if (empty($CFG->jsrev)) {
 418             $jsrev = 1;
 419         } else {
 420             $jsrev = $CFG->jsrev;
 421         }
 422
 423         return $jsrev;
 424     }
 425
 426     /**
 427      * Determine the correct Template revision to use for this load.
 428      *
 429      * @return int the templaterev to use.
 430      */
 431     protected function get_templaterev() {
 432         global $CFG;
 433
 434         if (empty($CFG->cachetemplates)) {
 435             $templaterev = -1;
 436         } else if (empty($CFG->templaterev)) {
 437             $templaterev = 1;
 438         } else {
 439             $templaterev = $CFG->templaterev;
 440         }
 441
 442         return $templaterev;
 443     }
 444
 445     /**
 446      * Ensure that the specified JavaScript file is linked to from this page.
 447      *
 448      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 449      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 450      *
 451      * By default the link is put at the end of the page, since this gives best page-load performance.
 452      *
 453      * Even if a particular script is requested more than once, it will only be linked
 454      * to once.
 455      *
 456      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 457      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 458      * @param bool $inhead initialise in head
 459      */
 460     public function js($url, $inhead = false) {
 461         $url = $this->js_fix_url($url);
 462         $where = $inhead ? 'head' : 'footer';
 463         $this->jsincludes[$where][$url->out()] = $url;
 464     }
 465
 466     /**
 467      * Request inclusion of jQuery library in the page.
 468      *
 469      * NOTE: this should not be used in official Moodle distribution!
 470      *
 471      * {@see http://docs.moodle.org/dev/jQuery}
 472      */
 473     public function jquery() {
 474         $this->jquery_plugin('jquery');
 475     }
 476
 477     /**
 478      * Request inclusion of jQuery plugin.
 479      *
 480      * NOTE: this should not be used in official Moodle distribution!
 481      *
 482      * jQuery plugins are located in plugin/jquery/* subdirectory,
 483      * plugin/jquery/plugins.php lists all available plugins.
 484      *
 485      * Included core plugins:
 486      *   - jQuery UI
 487      *
 488      * Add-ons may include extra jQuery plugins in jquery/ directory,
 489      * plugins.php file defines the mapping between plugin names and
 490      * necessary page includes.
 491      *
 492      * Examples:
 493      * <code>
 494      *   // file: mod/xxx/view.php
 495      *   $PAGE->requires->jquery();
 496      *   $PAGE->requires->jquery_plugin('ui');
 497      *   $PAGE->requires->jquery_plugin('ui-css');
 498      * </code>
 499      *
 500      * <code>
 501      *   // file: theme/yyy/lib.php
 502      *   function theme_yyy_page_init(moodle_page $page) {
 503      *       $page->requires->jquery();
 504      *       $page->requires->jquery_plugin('ui');
 505      *       $page->requires->jquery_plugin('ui-css');
 506      *   }
 507      * </code>
 508      *
 509      * <code>
 510      *   // file: blocks/zzz/block_zzz.php
 511      *   public function get_required_javascript() {
 512      *       parent::get_required_javascript();
 513      *       $this->page->requires->jquery();
 514      *       $page->requires->jquery_plugin('ui');
 515      *       $page->requires->jquery_plugin('ui-css');
 516      *   }
 517      * </code>
 518      *
 519      * {@see http://docs.moodle.org/dev/jQuery}
 520      *
 521      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 522      * @param string $component name of the component
 523      * @return bool success
 524      */
 525     public function jquery_plugin($plugin, $component = 'core') {
 526         global $CFG;
 527
 528         if ($this->headdone) {
 529             debugging('Can not add jQuery plugins after starting page output!');
 530             return false;
 531         }
 532
 533         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css'))) {
 534             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 535             $component = 'core';
 536         } else if ($component !== 'core' and strpos($component, '_') === false) {
 537             // Let's normalise the legacy activity names, Frankenstyle rulez!
 538             $component = 'mod_' . $component;
 539         }
 540
 541         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 542             // Make sure the jQuery itself is always loaded first,
 543             // the order of all other plugins depends on order of $PAGE_>requires->.
 544             $this->jquery_plugin('jquery', 'core');
 545         }
 546
 547         if (isset($this->jqueryplugins[$plugin])) {
 548             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 549             return true;
 550         }
 551
 552         $componentdir = core_component::get_component_directory($component);
 553         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 554             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 555             return false;
 556         }
 557
 558         $plugins = array();
 559         require("$componentdir/jquery/plugins.php");
 560
 561         if (!isset($plugins[$plugin])) {
 562             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 563             return false;
 564         }
 565
 566         $this->jqueryplugins[$plugin] = new stdClass();
 567         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 568         $this->jqueryplugins[$plugin]->component = $component;
 569         $this->jqueryplugins[$plugin]->urls      = array();
 570
 571         foreach ($plugins[$plugin]['files'] as $file) {
 572             if ($CFG->debugdeveloper) {
 573                 if (!file_exists("$componentdir/jquery/$file")) {
 574                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 575                     continue;
 576                 }
 577                 $file = str_replace('.min.css', '.css', $file);
 578                 $file = str_replace('.min.js', '.js', $file);
 579             }
 580             if (!file_exists("$componentdir/jquery/$file")) {
 581                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 582                 continue;
 583             }
 584             if (!empty($CFG->slasharguments)) {
 585                 $url = new moodle_url("/theme/jquery.php");
 586                 $url->set_slashargument("/$component/$file");
 587
 588             } else {
 589                 // This is not really good, we need slasharguments for relative links, this means no caching...
 590                 $path = realpath("$componentdir/jquery/$file");
 591                 if (strpos($path, $CFG->dirroot) === 0) {
 592                     $url = $CFG->wwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 593                     // Replace all occurences of backslashes characters in url to forward slashes.
 594                     $url = str_replace('\\', '/', $url);
 595                     $url = new moodle_url($url);
 596                 } else {
 597                     // Bad luck, fix your server!
 598                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 599                     continue;
 600                 }
 601             }
 602             $this->jqueryplugins[$plugin]->urls[] = $url;
 603         }
 604
 605         return true;
 606     }
 607
 608     /**
 609      * Request replacement of one jQuery plugin by another.
 610      *
 611      * This is useful when themes want to replace the jQuery UI theme,
 612      * the problem is that theme can not prevent others from including the core ui-css plugin.
 613      *
 614      * Example:
 615      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 616      *  2/ write theme/yourtheme/jquery/plugins.php
 617      *  3/ init jQuery from theme
 618      *
 619      * <code>
 620      *   // file theme/yourtheme/lib.php
 621      *   function theme_yourtheme_page_init($page) {
 622      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 623      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 624      *   }
 625      * </code>
 626      *
 627      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 628      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 629      *
 630      * {@see http://docs.moodle.org/dev/jQuery}
 631      *
 632      * @param string $oldplugin original plugin
 633      * @param string $newplugin the replacement
 634      */
 635     public function jquery_override_plugin($oldplugin, $newplugin) {
 636         if ($this->headdone) {
 637             debugging('Can not override jQuery plugins after starting page output!');
 638             return;
 639         }
 640         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 641     }
 642
 643     /**
 644      * Return jQuery related markup for page start.
 645      * @return string
 646      */
 647     protected function get_jquery_headcode() {
 648         if (empty($this->jqueryplugins['jquery'])) {
 649             // If nobody requested jQuery then do not bother to load anything.
 650             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 651             return '';
 652         }
 653
 654         $included = array();
 655         $urls = array();
 656
 657         foreach ($this->jqueryplugins as $name => $unused) {
 658             if (isset($included[$name])) {
 659                 continue;
 660             }
 661             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 662                 // The following loop tries to resolve the replacements,
 663                 // use max 100 iterations to prevent infinite loop resulting
 664                 // in blank page.
 665                 $cyclic = true;
 666                 $oldname = $name;
 667                 for ($i=0; $i<100; $i++) {
 668                     $name = $this->jquerypluginoverrides[$name];
 669                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 670                         $cyclic = false;
 671                         break;
 672                     }
 673                 }
 674                 if ($cyclic) {
 675                     // We can not do much with cyclic references here, let's use the old plugin.
 676                     $name = $oldname;
 677                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 678
 679                 } else if (empty($name)) {
 680                     // Developer requested removal of the plugin.
 681                     continue;
 682
 683                 } else if (!isset($this->jqueryplugins[$name])) {
 684                     debugging("Unknown jQuery override plugin '$name' detected");
 685                     $name = $oldname;
 686
 687                 } else if (isset($included[$name])) {
 688                     // The plugin was already included, easy.
 689                     continue;
 690                 }
 691             }
 692
 693             $plugin = $this->jqueryplugins[$name];
 694             $urls = array_merge($urls, $plugin->urls);
 695             $included[$name] = true;
 696         }
 697
 698         $output = '';
 699         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 700         foreach ($urls as $url) {
 701             if (preg_match('/\.js$/', $url)) {
 702                 $output .= html_writer::script('', $url);
 703             } else if (preg_match('/\.css$/', $url)) {
 704                 $attributes['href'] = $url;
 705                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 706             }
 707         }
 708
 709         return $output;
 710     }
 711
 712     /**
 713      * Returns the actual url through which a script is served.
 714      *
 715      * @param moodle_url|string $url full moodle url, or shortened path to script
 716      * @return moodle_url
 717      */
 718     protected function js_fix_url($url) {
 719         global $CFG;
 720
 721         if ($url instanceof moodle_url) {
 722             return $url;
 723         } else if (strpos($url, '/') === 0) {
 724             // Fix the admin links if needed.
 725             if ($CFG->admin !== 'admin') {
 726                 if (strpos($url, "/admin/") === 0) {
 727                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 728                 }
 729             }
 730             if (debugging()) {
 731                 // Check file existence only when in debug mode.
 732                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 733                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 734                 }
 735             }
 736             if (substr($url, -3) === '.js') {
 737                 $jsrev = $this->get_jsrev();
 738                 if (empty($CFG->slasharguments)) {
 739                     return new moodle_url('/lib/javascript.php', array('rev'=>$jsrev, 'jsfile'=>$url));
 740                 } else {
 741                     $returnurl = new moodle_url('/lib/javascript.php');
 742                     $returnurl->set_slashargument('/'.$jsrev.$url);
 743                     return $returnurl;
 744                 }
 745             } else {
 746                 return new moodle_url($url);
 747             }
 748         } else {
 749             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 750         }
 751     }
 752
 753     /**
 754      * Find out if JS module present and return details.
 755      *
 756      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 757      * @return array description of module or null if not found
 758      */
 759     protected function find_module($component) {
 760         global $CFG, $PAGE;
 761
 762         $module = null;
 763
 764         if (strpos($component, 'core_') === 0) {
 765             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 766             // so that we do nto have to repeat the definition of these modules over and over again.
 767             switch($component) {
 768                 case 'core_filepicker':
 769                     $module = array('name'     => 'core_filepicker',
 770                                     'fullpath' => '/repository/filepicker.js',
 771                                     'requires' => array(
 772                                         'base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form',
 773                                         'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin',
 774                                         'escape', 'moodle-core_filepicker', 'moodle-core-notification-dialogue'
 775                                     ),
 776                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 777                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 778                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 779                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 780                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 781                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 782                                                         array('referencesexist', 'repository'), array('select', 'repository')
 783                                                     ));
 784                     break;
 785                 case 'core_comment':
 786                     $module = array('name'     => 'core_comment',
 787                                     'fullpath' => '/comment/comment.js',
 788                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay', 'escape'),
 789                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 790                                 );
 791                     break;
 792                 case 'core_role':
 793                     $module = array('name'     => 'core_role',
 794                                     'fullpath' => '/admin/roles/module.js',
 795                                     'requires' => array('node', 'cookie'));
 796                     break;
 797                 case 'core_completion':
 798                     break;
 799                 case 'core_message':
 800                     $module = array('name'     => 'core_message',
 801                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 802                                     'fullpath' => '/message/module.js');
 803                     break;
 804                 case 'core_group':
 805                     $module = array('name'     => 'core_group',
 806                                     'fullpath' => '/group/module.js',
 807                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 808                     break;
 809                 case 'core_question_engine':
 810                     $module = array('name'     => 'core_question_engine',
 811                                     'fullpath' => '/question/qengine.js',
 812                                     'requires' => array('node', 'event'));
 813                     break;
 814                 case 'core_rating':
 815                     $module = array('name'     => 'core_rating',
 816                                     'fullpath' => '/rating/module.js',
 817                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 818                     break;
 819                 case 'core_dndupload':
 820                     $module = array('name'     => 'core_dndupload',
 821                                     'fullpath' => '/lib/form/dndupload.js',
 822                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 823                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 824                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesfile', 'error'),
 825                                                         array('sizegb', 'moodle'), array('sizemb', 'moodle'), array('sizekb', 'moodle'), array('sizeb', 'moodle'),
 826                                                         array('maxareabytesreached', 'moodle'), array('serverconnection', 'error'),
 827                                                         array('changesmadereallygoaway', 'moodle'), array('complete', 'moodle')
 828                                                     ));
 829                     break;
 830             }
 831
 832         } else {
 833             if ($dir = core_component::get_component_directory($component)) {
 834                 if (file_exists("$dir/module.js")) {
 835                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 836                         $dir = substr($dir, strlen($CFG->dirroot));
 837                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 838                     }
 839                 }
 840             }
 841         }
 842
 843         return $module;
 844     }
 845
 846     /**
 847      * Append YUI3 module to default YUI3 JS loader.
 848      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 849      *
 850      * @param string|array $module name of module (details are autodetected), or full module specification as array
 851      * @return void
 852      */
 853     public function js_module($module) {
 854         global $CFG;
 855
 856         if (empty($module)) {
 857             throw new coding_exception('Missing YUI3 module name or full description.');
 858         }
 859
 860         if (is_string($module)) {
 861             $module = $this->find_module($module);
 862         }
 863
 864         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 865             throw new coding_exception('Missing YUI3 module details.');
 866         }
 867
 868         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 869         // Add all needed strings.
 870         if (!empty($module['strings'])) {
 871             foreach ($module['strings'] as $string) {
 872                 $identifier = $string[0];
 873                 $component = isset($string[1]) ? $string[1] : 'moodle';
 874                 $a = isset($string[2]) ? $string[2] : null;
 875                 $this->string_for_js($identifier, $component, $a);
 876             }
 877         }
 878         unset($module['strings']);
 879
 880         // Process module requirements and attempt to load each. This allows
 881         // moodle modules to require each other.
 882         if (!empty($module['requires'])){
 883             foreach ($module['requires'] as $requirement) {
 884                 $rmodule = $this->find_module($requirement);
 885                 if (is_array($rmodule)) {
 886                     $this->js_module($rmodule);
 887                 }
 888             }
 889         }
 890
 891         if ($this->headdone) {
 892             $this->extramodules[$module['name']] = $module;
 893         } else {
 894             $this->YUI_config->add_module_config($module['name'], $module);
 895         }
 896     }
 897
 898     /**
 899      * Returns true if the module has already been loaded.
 900      *
 901      * @param string|array $module
 902      * @return bool True if the module has already been loaded
 903      */
 904     protected function js_module_loaded($module) {
 905         if (is_string($module)) {
 906             $modulename = $module;
 907         } else {
 908             $modulename = $module['name'];
 909         }
 910         return array_key_exists($modulename, $this->YUI_config->modules) ||
 911                array_key_exists($modulename, $this->extramodules);
 912     }
 913
 914     /**
 915      * Ensure that the specified CSS file is linked to from this page.
 916      *
 917      * Because stylesheet links must go in the <head> part of the HTML, you must call
 918      * this function before {@link get_head_code()} is called. That normally means before
 919      * the call to print_header. If you call it when it is too late, an exception
 920      * will be thrown.
 921      *
 922      * Even if a particular style sheet is requested more than once, it will only
 923      * be linked to once.
 924      *
 925      * Please note use of this feature is strongly discouraged,
 926      * it is suitable only for places where CSS is submitted directly by teachers.
 927      * (Students must not be allowed to submit any external CSS because it may
 928      * contain embedded javascript!). Example of correct use is mod/data.
 929      *
 930      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 931      *   For example:
 932      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 933      */
 934     public function css($stylesheet) {
 935         global $CFG;
 936
 937         if ($this->headdone) {
 938             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 939         }
 940
 941         if ($stylesheet instanceof moodle_url) {
 942             // ok
 943         } else if (strpos($stylesheet, '/') === 0) {
 944             $stylesheet = new moodle_url($stylesheet);
 945         } else {
 946             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 947         }
 948
 949         $this->cssurls[$stylesheet->out()] = $stylesheet;
 950     }
 951
 952     /**
 953      * Add theme stylesheet to page - do not use from plugin code,
 954      * this should be called only from the core renderer!
 955      *
 956      * @param moodle_url $stylesheet
 957      * @return void
 958      */
 959     public function css_theme(moodle_url $stylesheet) {
 960         $this->cssthemeurls[] = $stylesheet;
 961     }
 962
 963     /**
 964      * Ensure that a skip link to a given target is printed at the top of the <body>.
 965      *
 966      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 967      * will be thrown). That normally means you must call this before the call to print_header.
 968      *
 969      * If you ask for a particular skip link to be printed, it is then your responsibility
 970      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 971      * page, so that the skip link goes somewhere.
 972      *
 973      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 974      *
 975      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 976      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 977      */
 978     public function skip_link_to($target, $linktext) {
 979         if ($this->topofbodydone) {
 980             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 981             return;
 982         }
 983         $this->skiplinks[$target] = $linktext;
 984     }
 985
 986     /**
 987      * !!!DEPRECATED!!! please use js_init_call() if possible
 988      * Ensure that the specified JavaScript function is called from an inline script
 989      * somewhere on this page.
 990      *
 991      * By default the call will be put in a script tag at the
 992      * end of the page after initialising Y instance, since this gives best page-load
 993      * performance and allows you to use YUI3 library.
 994      *
 995      * If you request that a particular function is called several times, then
 996      * that is what will happen (unlike linking to a CSS or JS file, where only
 997      * one link will be output).
 998      *
 999      * The main benefit of the method is the automatic encoding of all function parameters.
1000      *
1001      * @deprecated
1002      *
1003      * @param string $function the name of the JavaScritp function to call. Can
1004      *      be a compound name like 'Y.Event.purgeElement'. Can also be
1005      *      used to create and object by using a 'function name' like 'new user_selector'.
1006      * @param array $arguments and array of arguments to be passed to the function.
1007      *      When generating the function call, this will be escaped using json_encode,
1008      *      so passing objects and arrays should work.
1009      * @param bool $ondomready If tru the function is only called when the dom is
1010      *      ready for manipulation.
1011      * @param int $delay The delay before the function is called.
1012      */
1013     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
1014         $where = $ondomready ? 'ondomready' : 'normal';
1015         $this->jscalls[$where][] = array($function, $arguments, $delay);
1016     }
1017
1018     /**
1019      * This function appends a block of code to the AMD specific javascript block executed
1020      * in the page footer, just after loading the requirejs library.
1021      *
1022      * The code passed here can rely on AMD module loading, e.g. require('jquery', function($) {...});
1023      *
1024      * @param string $code The JS code to append.
1025      */
1026     public function js_amd_inline($code) {
1027         $this->amdjscode[] = $code;
1028     }
1029
1030     /**
1031      * Load an AMD module and eventually call its method.
1032      *
1033      * This function creates a minimal inline JS snippet that requires an AMD module and eventually calls a single
1034      * function from the module with given arguments. If it is called multiple times, it will be create multiple
1035      * snippets.
1036      *
1037      * @param string $fullmodule The name of the AMD module to load, formatted as <component name>/<module name>.
1038      * @param string $func Optional function from the module to call, defaults to just loading the AMD module.
1039      * @param array $params The params to pass to the function (will be serialized into JSON).
1040      */
1041     public function js_call_amd($fullmodule, $func = null, $params = array()) {
1042         global $CFG;
1043
1044         $modulepath = explode('/', $fullmodule);
1045
1046         $modname = clean_param(array_shift($modulepath), PARAM_COMPONENT);
1047         foreach ($modulepath as $module) {
1048             $modname .= '/' . clean_param($module, PARAM_ALPHANUMEXT);
1049         }
1050
1051         $functioncode = [];
1052         if ($func !== null) {
1053             $func = clean_param($func, PARAM_ALPHANUMEXT);
1054
1055             $jsonparams = array();
1056             foreach ($params as $param) {
1057                 $jsonparams[] = json_encode($param);
1058             }
1059             $strparams = implode(', ', $jsonparams);
1060             if ($CFG->debugdeveloper) {
1061                 $toomanyparamslimit = 1024;
1062                 if (strlen($strparams) > $toomanyparamslimit) {
1063                     debugging('Too much data passed as arguments to js_call_amd("' . $fullmodule . '", "' . $func .
1064                         '"). Generally there are better ways to pass lots of data from PHP to JavaScript, for example via Ajax, ' .
1065                         'data attributes, ... . This warning is triggered if the argument string becomes longer than ' .
1066                         $toomanyparamslimit . ' characters.', DEBUG_DEVELOPER);
1067                 }
1068             }
1069
1070             $functioncode[] = "amd.{$func}({$strparams});";
1071         }
1072
1073         $functioncode[] = "M.util.js_complete('{$modname}');";
1074
1075         $initcode = implode(' ', $functioncode);
1076         $js = "M.util.js_pending('{$modname}'); require(['{$modname}'], function(amd) {{$initcode}});";
1077
1078         $this->js_amd_inline($js);
1079     }
1080
1081     /**
1082      * Creates a JavaScript function call that requires one or more modules to be loaded.
1083      *
1084      * This function can be used to include all of the standard YUI module types within JavaScript:
1085      *     - YUI3 modules    [node, event, io]
1086      *     - YUI2 modules    [yui2-*]
1087      *     - Moodle modules  [moodle-*]
1088      *     - Gallery modules [gallery-*]
1089      *
1090      * Before writing new code that makes extensive use of YUI, you should consider it's replacement AMD/JQuery.
1091      * @see js_call_amd()
1092      *
1093      * @param array|string $modules One or more modules
1094      * @param string $function The function to call once modules have been loaded
1095      * @param array $arguments An array of arguments to pass to the function
1096      * @param string $galleryversion Deprecated: The gallery version to use
1097      * @param bool $ondomready
1098      */
1099     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
1100         if (!is_array($modules)) {
1101             $modules = array($modules);
1102         }
1103
1104         if ($galleryversion != null) {
1105             debugging('The galleryversion parameter to yui_module has been deprecated since Moodle 2.3.');
1106         }
1107
1108         $jscode = 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
1109         if ($ondomready) {
1110             $jscode = "Y.on('domready', function() { $jscode });";
1111         }
1112         $this->jsinitcode[] = $jscode;
1113     }
1114
1115     /**
1116      * Set the CSS Modules to be included from YUI.
1117      *
1118      * @param array $modules The list of YUI CSS Modules to include.
1119      */
1120     public function set_yuicssmodules(array $modules = array()) {
1121         $this->yuicssmodules = $modules;
1122     }
1123
1124     /**
1125      * Ensure that the specified JavaScript function is called from an inline script
1126      * from page footer.
1127      *
1128      * @param string $function the name of the JavaScritp function to with init code,
1129      *      usually something like 'M.mod_mymodule.init'
1130      * @param array $extraarguments and array of arguments to be passed to the function.
1131      *      The first argument is always the YUI3 Y instance with all required dependencies
1132      *      already loaded.
1133      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1134      * @param array $module JS module specification array
1135      */
1136     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
1137         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
1138         if (!$module) {
1139             // Detect module automatically.
1140             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
1141                 $module = $this->find_module($matches[1]);
1142             }
1143         }
1144
1145         $this->js_init_code($jscode, $ondomready, $module);
1146     }
1147
1148     /**
1149      * Add short static javascript code fragment to page footer.
1150      * This is intended primarily for loading of js modules and initialising page layout.
1151      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1152      * may override it.
1153      *
1154      * @param string $jscode
1155      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1156      * @param array $module JS module specification array
1157      */
1158     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1159         $jscode = trim($jscode, " ;\n"). ';';
1160
1161         $uniqid = html_writer::random_id();
1162         $startjs = " M.util.js_pending('" . $uniqid . "');";
1163         $endjs = " M.util.js_complete('" . $uniqid . "');";
1164
1165         if ($module) {
1166             $this->js_module($module);
1167             $modulename = $module['name'];
1168             $jscode = "$startjs Y.use('$modulename', function(Y) { $jscode $endjs });";
1169         }
1170
1171         if ($ondomready) {
1172             $jscode = "$startjs Y.on('domready', function() { $jscode $endjs });";
1173         }
1174
1175         $this->jsinitcode[] = $jscode;
1176     }
1177
1178     /**
1179      * Make a language string available to JavaScript.
1180      *
1181      * All the strings will be available in a M.str object in the global namespace.
1182      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1183      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1184      * equivalent in the current language.
1185      *
1186      * The arguments to this function are just like the arguments to get_string
1187      * except that $component is not optional, and there are some aspects to consider
1188      * when the string contains {$a} placeholder.
1189      *
1190      * If the string does not contain any {$a} placeholder, you can simply use
1191      * M.str.component.identifier to obtain it. If you prefer, you can call
1192      * M.util.get_string(identifier, component) to get the same result.
1193      *
1194      * If you need to use {$a} placeholders, there are two options. Either the
1195      * placeholder should be substituted in PHP on server side or it should
1196      * be substituted in Javascript at client side.
1197      *
1198      * To substitute the placeholder at server side, just provide the required
1199      * value for the placeholder when you require the string. Because each string
1200      * is only stored once in the JavaScript (based on $identifier and $module)
1201      * you cannot get the same string with two different values of $a. If you try,
1202      * an exception will be thrown. Once the placeholder is substituted, you can
1203      * use M.str or M.util.get_string() as shown above:
1204      *
1205      *     // Require the string in PHP and replace the placeholder.
1206      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1207      *     // Use the result of the substitution in Javascript.
1208      *     alert(M.str.moodle.fullnamedisplay);
1209      *
1210      * To substitute the placeholder at client side, use M.util.get_string()
1211      * function. It implements the same logic as {@link get_string()}:
1212      *
1213      *     // Require the string in PHP but keep {$a} as it is.
1214      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1215      *     // Provide the values on the fly in Javascript.
1216      *     user = { firstname : 'Harry', lastname : 'Potter' }
1217      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1218      *
1219      * If you do need the same string expanded with different $a values in PHP
1220      * on server side, then the solution is to put them in your own data structure
1221      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1222      *
1223      * @param string $identifier the desired string.
1224      * @param string $component the language file to look in.
1225      * @param mixed $a any extra data to add into the string (optional).
1226      */
1227     public function string_for_js($identifier, $component, $a = null) {
1228         if (!$component) {
1229             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1230         }
1231         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1232             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1233                     "from lang file '$component' with different \$a parameter?");
1234         }
1235         if (!isset($this->stringsforjs[$component][$identifier])) {
1236             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1237             $this->stringsforjs_as[$component][$identifier] = $a;
1238         }
1239     }
1240
1241     /**
1242      * Make an array of language strings available for JS.
1243      *
1244      * This function calls the above function {@link string_for_js()} for each requested
1245      * string in the $identifiers array that is passed to the argument for a single module
1246      * passed in $module.
1247      *
1248      * <code>
1249      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1250      *
1251      * // The above is identical to calling:
1252      *
1253      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1254      * $PAGE->requires->string_for_js('two', 'mymod');
1255      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1256      * </code>
1257      *
1258      * @param array $identifiers An array of desired strings
1259      * @param string $component The module to load for
1260      * @param mixed $a This can either be a single variable that gets passed as extra
1261      *         information for every string or it can be an array of mixed data where the
1262      *         key for the data matches that of the identifier it is meant for.
1263      *
1264      */
1265     public function strings_for_js($identifiers, $component, $a = null) {
1266         foreach ($identifiers as $key => $identifier) {
1267             if (is_array($a) && array_key_exists($key, $a)) {
1268                 $extra = $a[$key];
1269             } else {
1270                 $extra = $a;
1271             }
1272             $this->string_for_js($identifier, $component, $extra);
1273         }
1274     }
1275
1276     /**
1277      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1278      *
1279      * Make some data from PHP available to JavaScript code.
1280      *
1281      * For example, if you call
1282      * <pre>
1283      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1284      * </pre>
1285      * then in JavsScript mydata.name will be 'Moodle'.
1286      *
1287      * @deprecated
1288      * @param string $variable the the name of the JavaScript variable to assign the data to.
1289      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1290      *      should be considered an experimental feature.
1291      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1292      *      so passing objects and arrays should work.
1293      * @param bool $inhead initialise in head
1294      * @return void
1295      */
1296     public function data_for_js($variable, $data, $inhead=false) {
1297         $where = $inhead ? 'head' : 'footer';
1298         $this->jsinitvariables[$where][] = array($variable, $data);
1299     }
1300
1301     /**
1302      * Creates a YUI event handler.
1303      *
1304      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1305      * @param string $event A valid DOM event (click, mousedown, change etc.)
1306      * @param string $function The name of the function to call
1307      * @param array  $arguments An optional array of argument parameters to pass to the function
1308      */
1309     public function event_handler($selector, $event, $function, array $arguments = null) {
1310         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1311     }
1312
1313     /**
1314      * Returns code needed for registering of event handlers.
1315      * @return string JS code
1316      */
1317     protected function get_event_handler_code() {
1318         $output = '';
1319         foreach ($this->eventhandlers as $h) {
1320             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1321         }
1322         return $output;
1323     }
1324
1325     /**
1326      * Get the inline JavaScript code that need to appear in a particular place.
1327      * @param bool $ondomready
1328      * @return string
1329      */
1330     protected function get_javascript_code($ondomready) {
1331         $where = $ondomready ? 'ondomready' : 'normal';
1332         $output = '';
1333         if ($this->jscalls[$where]) {
1334             foreach ($this->jscalls[$where] as $data) {
1335                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1336             }
1337             if (!empty($ondomready)) {
1338                 $output = "    Y.on('domready', function() {\n$output\n});";
1339             }
1340         }
1341         return $output;
1342     }
1343
1344     /**
1345      * Returns js code to be executed when Y is available.
1346      * @return string
1347      */
1348     protected function get_javascript_init_code() {
1349         if (count($this->jsinitcode)) {
1350             return implode("\n", $this->jsinitcode) . "\n";
1351         }
1352         return '';
1353     }
1354
1355     /**
1356      * Returns js code to load amd module loader, then insert inline script tags
1357      * that contain require() calls using RequireJS.
1358      * @return string
1359      */
1360     protected function get_amd_footercode() {
1361         global $CFG;
1362         $output = '';
1363
1364         // We will cache JS if cachejs is not set, or it is true.
1365         $cachejs = !isset($CFG->cachejs) || $CFG->cachejs;
1366         $jsrev = $this->get_jsrev();
1367
1368         $jsloader = new moodle_url('/lib/javascript.php');
1369         $jsloader->set_slashargument('/' . $jsrev . '/');
1370         $requirejsloader = new moodle_url('/lib/requirejs.php');
1371         $requirejsloader->set_slashargument('/' . $jsrev . '/');
1372
1373         $requirejsconfig = file_get_contents($CFG->dirroot . '/lib/requirejs/moodle-config.js');
1374
1375         // No extension required unless slash args is disabled.
1376         $jsextension = '.js';
1377         if (!empty($CFG->slasharguments)) {
1378             $jsextension = '';
1379         }
1380
1381         $minextension = '.min';
1382         if (!$cachejs) {
1383             $minextension = '';
1384         }
1385
1386         $requirejsconfig = str_replace('[BASEURL]', $requirejsloader, $requirejsconfig);
1387         $requirejsconfig = str_replace('[JSURL]', $jsloader, $requirejsconfig);
1388         $requirejsconfig = str_replace('[JSMIN]', $minextension, $requirejsconfig);
1389         $requirejsconfig = str_replace('[JSEXT]', $jsextension, $requirejsconfig);
1390
1391         $output .= html_writer::script($requirejsconfig);
1392         if ($cachejs) {
1393             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.min.js'));
1394         } else {
1395             $output .= html_writer::script('', $this->js_fix_url('/lib/requirejs/require.js'));
1396         }
1397
1398         // First include must be to a module with no dependencies, this prevents multiple requests.
1399         $prefix = <<<EOF
1400 M.util.js_pending("core/first");
1401 require(['core/first'], function() {
1402
1403 EOF;
1404
1405         if (during_initial_install()) {
1406             // Do not run a prefetch during initial install as the DB is not available to service WS calls.
1407             $prefetch = '';
1408         } else {
1409             $prefetch = "require(['core/prefetch'])\n";
1410         }
1411
1412         $suffix = <<<EOF
1413
1414     M.util.js_complete("core/first");
1415 });
1416 EOF;
1417
1418         $output .= html_writer::script($prefix . $prefetch . implode(";\n", $this->amdjscode) . $suffix);
1419         return $output;
1420     }
1421
1422     /**
1423      * Returns basic YUI3 CSS code.
1424      *
1425      * @return string
1426      */
1427     protected function get_yui3lib_headcss() {
1428         global $CFG;
1429
1430         $yuiformat = '-min';
1431         if ($this->yui3loader->filter === 'RAW') {
1432             $yuiformat = '';
1433         }
1434
1435         $code = '';
1436         if ($this->yui3loader->combine) {
1437             if (!empty($this->yuicssmodules)) {
1438                 $modules = array();
1439                 foreach ($this->yuicssmodules as $module) {
1440                     $modules[] = "$CFG->yui3version/$module/$module-min.css";
1441                 }
1442                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1443             }
1444             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1445
1446         } else {
1447             if (!empty($this->yuicssmodules)) {
1448                 foreach ($this->yuicssmodules as $module) {
1449                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1450                 }
1451             }
1452             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->local_comboBase.'rollup/'.$CFG->yui3version.'/yui-moodlesimple' . $yuiformat . '.css" />';
1453         }
1454
1455         if ($this->yui3loader->filter === 'RAW') {
1456             $code = str_replace('-min.css', '.css', $code);
1457         } else if ($this->yui3loader->filter === 'DEBUG') {
1458             $code = str_replace('-min.css', '.css', $code);
1459         }
1460         return $code;
1461     }
1462
1463     /**
1464      * Returns basic YUI3 JS loading code.
1465      *
1466      * @return string
1467      */
1468     protected function get_yui3lib_headcode() {
1469         global $CFG;
1470
1471         $jsrev = $this->get_jsrev();
1472
1473         $yuiformat = '-min';
1474         if ($this->yui3loader->filter === 'RAW') {
1475             $yuiformat = '';
1476         }
1477
1478         $format = '-min';
1479         if ($this->YUI_config->groups['moodle']['filter'] === 'DEBUG') {
1480             $format = '-debug';
1481         }
1482
1483         $rollupversion = $CFG->yui3version;
1484         if (!empty($CFG->yuipatchlevel)) {
1485             $rollupversion .= '_' . $CFG->yuipatchlevel;
1486         }
1487
1488         $baserollups = array(
1489             'rollup/' . $rollupversion . "/yui-moodlesimple{$yuiformat}.js",
1490         );
1491
1492         if ($this->yui3loader->combine) {
1493             return '<script src="' .
1494                     $this->yui3loader->local_comboBase .
1495                     implode('&amp;', $baserollups) .
1496                     '"></script>';
1497         } else {
1498             $code = '';
1499             foreach ($baserollups as $rollup) {
1500                 $code .= '<script src="'.$this->yui3loader->local_comboBase.$rollup.'"></script>';
1501             }
1502             return $code;
1503         }
1504
1505     }
1506
1507     /**
1508      * Returns html tags needed for inclusion of theme CSS.
1509      *
1510      * @return string
1511      */
1512     protected function get_css_code() {
1513         // First of all the theme CSS, then any custom CSS
1514         // Please note custom CSS is strongly discouraged,
1515         // because it can not be overridden by themes!
1516         // It is suitable only for things like mod/data which accepts CSS from teachers.
1517         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1518
1519         // Add the YUI code first. We want this to be overridden by any Moodle CSS.
1520         $code = $this->get_yui3lib_headcss();
1521
1522         // This line of code may look funny but it is currently required in order
1523         // to avoid MASSIVE display issues in Internet Explorer.
1524         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1525         // ignored whenever another resource is added until such time as a redraw
1526         // is forced, usually by moving the mouse over the affected element.
1527         $code .= html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1528
1529         $urls = $this->cssthemeurls + $this->cssurls;
1530         foreach ($urls as $url) {
1531             $attributes['href'] = $url;
1532             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1533             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1534             unset($attributes['id']);
1535         }
1536
1537         return $code;
1538     }
1539
1540     /**
1541      * Adds extra modules specified after printing of page header.
1542      *
1543      * @return string
1544      */
1545     protected function get_extra_modules_code() {
1546         if (empty($this->extramodules)) {
1547             return '';
1548         }
1549         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1550     }
1551
1552     /**
1553      * Generate any HTML that needs to go inside the <head> tag.
1554      *
1555      * Normally, this method is called automatically by the code that prints the
1556      * <head> tag. You should not normally need to call it in your own code.
1557      *
1558      * @param moodle_page $page
1559      * @param core_renderer $renderer
1560      * @return string the HTML code to to inside the <head> tag.
1561      */
1562     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1563         global $CFG;
1564
1565         // Note: the $page and $output are not stored here because it would
1566         // create circular references in memory which prevents garbage collection.
1567         $this->init_requirements_data($page, $renderer);
1568
1569         $output = '';
1570
1571         // Add all standard CSS for this page.
1572         $output .= $this->get_css_code();
1573
1574         // Set up the M namespace.
1575         $js = "var M = {}; M.yui = {};\n";
1576
1577         // Capture the time now ASAP during page load. This minimises the lag when
1578         // we try to relate times on the server to times in the browser.
1579         // An example of where this is used is the quiz countdown timer.
1580         $js .= "M.pageloadstarttime = new Date();\n";
1581
1582         // Add a subset of Moodle configuration to the M namespace.
1583         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1584
1585         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1586         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1587         //       this needs to be done before including any other script.
1588         $js .= $this->YUI_config->get_config_functions();
1589         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1590         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1591         $js = $this->YUI_config->update_header_js($js);
1592
1593         $output .= html_writer::script($js);
1594
1595         // Add variables.
1596         if ($this->jsinitvariables['head']) {
1597             $js = '';
1598             foreach ($this->jsinitvariables['head'] as $data) {
1599                 list($var, $value) = $data;
1600                 $js .= js_writer::set_variable($var, $value, true);
1601             }
1602             $output .= html_writer::script($js);
1603         }
1604
1605         // Mark head sending done, it is not possible to anything there.
1606         $this->headdone = true;
1607
1608         return $output;
1609     }
1610
1611     /**
1612      * Generate any HTML that needs to go at the start of the <body> tag.
1613      *
1614      * Normally, this method is called automatically by the code that prints the
1615      * <head> tag. You should not normally need to call it in your own code.
1616      *
1617      * @param renderer_base $renderer
1618      * @return string the HTML code to go at the start of the <body> tag.
1619      */
1620     public function get_top_of_body_code(renderer_base $renderer) {
1621         global $CFG;
1622
1623         // First the skip links.
1624         $output = $renderer->render_skip_links($this->skiplinks);
1625
1626         // Include the Polyfills.
1627         $output .= html_writer::script('', $this->js_fix_url('/lib/polyfills/polyfill.js'));
1628
1629         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
1630         $output .= $this->get_yui3lib_headcode();
1631
1632         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1633         $output .= $this->get_jquery_headcode();
1634
1635         // Link our main JS file, all core stuff should be there.
1636         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1637
1638         // All the other linked things from HEAD - there should be as few as possible.
1639         if ($this->jsincludes['head']) {
1640             foreach ($this->jsincludes['head'] as $url) {
1641                 $output .= html_writer::script('', $url);
1642             }
1643         }
1644
1645         // Then the clever trick for hiding of things not needed when JS works.
1646         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1647         $this->topofbodydone = true;
1648         return $output;
1649     }
1650
1651     /**
1652      * Generate any HTML that needs to go at the end of the page.
1653      *
1654      * Normally, this method is called automatically by the code that prints the
1655      * page footer. You should not normally need to call it in your own code.
1656      *
1657      * @return string the HTML code to to at the end of the page.
1658      */
1659     public function get_end_code() {
1660         global $CFG;
1661         $output = '';
1662
1663         // Set the log level for the JS logging.
1664         $logconfig = new stdClass();
1665         $logconfig->level = 'warn';
1666         if ($CFG->debugdeveloper) {
1667             $logconfig->level = 'trace';
1668         }
1669         $this->js_call_amd('core/log', 'setConfig', array($logconfig));
1670         // Add any global JS that needs to run on all pages.
1671         $this->js_call_amd('core/page_global', 'init');
1672         $this->js_call_amd('core/utility');
1673
1674         // Call amd init functions.
1675         $output .= $this->get_amd_footercode();
1676
1677         // Add other requested modules.
1678         $output .= $this->get_extra_modules_code();
1679
1680         $this->js_init_code('M.util.js_complete("init");', true);
1681
1682         // All the other linked scripts - there should be as few as possible.
1683         if ($this->jsincludes['footer']) {
1684             foreach ($this->jsincludes['footer'] as $url) {
1685                 $output .= html_writer::script('', $url);
1686             }
1687         }
1688
1689         // Add all needed strings.
1690         // First add core strings required for some dialogues.
1691         $this->strings_for_js(array(
1692             'confirm',
1693             'yes',
1694             'no',
1695             'areyousure',
1696             'closebuttontitle',
1697             'unknownerror',
1698             'error',
1699             'file',
1700             'url',
1701             // TODO MDL-70830 shortforms should preload the collapseall/expandall strings properly.
1702             'collapseall',
1703             'expandall',
1704         ), 'moodle');
1705         $this->strings_for_js(array(
1706             'debuginfo',
1707             'line',
1708             'stacktrace',
1709         ), 'debug');
1710         $this->string_for_js('labelsep', 'langconfig');
1711         if (!empty($this->stringsforjs)) {
1712             $strings = array();
1713             foreach ($this->stringsforjs as $component=>$v) {
1714                 foreach($v as $indentifier => $langstring) {
1715                     $strings[$component][$indentifier] = $langstring->out();
1716                 }
1717             }
1718             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1719         }
1720
1721         // Add variables.
1722         if ($this->jsinitvariables['footer']) {
1723             $js = '';
1724             foreach ($this->jsinitvariables['footer'] as $data) {
1725                 list($var, $value) = $data;
1726                 $js .= js_writer::set_variable($var, $value, true);
1727             }
1728             $output .= html_writer::script($js);
1729         }
1730
1731         $inyuijs = $this->get_javascript_code(false);
1732         $ondomreadyjs = $this->get_javascript_code(true);
1733         $jsinit = $this->get_javascript_init_code();
1734         $handlersjs = $this->get_event_handler_code();
1735
1736         // There is a global Y, make sure it is available in your scope.
1737         $js = "(function() {{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}})();";
1738
1739         $output .= html_writer::script($js);
1740
1741         return $output;
1742     }
1743
1744     /**
1745      * Have we already output the code in the <head> tag?
1746      *
1747      * @return bool
1748      */
1749     public function is_head_done() {
1750         return $this->headdone;
1751     }
1752
1753     /**
1754      * Have we already output the code at the start of the <body> tag?
1755      *
1756      * @return bool
1757      */
1758     public function is_top_of_body_done() {
1759         return $this->topofbodydone;
1760     }
1761
1762     /**
1763      * Should we generate a bit of content HTML that is only required once  on
1764      * this page (e.g. the contents of the modchooser), now? Basically, we call
1765      * {@link has_one_time_item_been_created()}, and if the thing has not already
1766      * been output, we return true to tell the caller to generate it, and also
1767      * call {@link set_one_time_item_created()} to record the fact that it is
1768      * about to be generated.
1769      *
1770      * That is, a typical usage pattern (in a renderer method) is:
1771      * <pre>
1772      * if (!$this->page->requires->should_create_one_time_item_now($thing)) {
1773      *     return '';
1774      * }
1775      * // Else generate it.
1776      * </pre>
1777      *
1778      * @param string $thing identifier for the bit of content. Should be of the form
1779      *      frankenstyle_things, e.g. core_course_modchooser.
1780      * @return bool if true, the caller should generate that bit of output now, otherwise don't.
1781      */
1782     public function should_create_one_time_item_now($thing) {
1783         if ($this->has_one_time_item_been_created($thing)) {
1784             return false;
1785         }
1786
1787         $this->set_one_time_item_created($thing);
1788         return true;
1789     }
1790
1791     /**
1792      * Has a particular bit of HTML that is only required once  on this page
1793      * (e.g. the contents of the modchooser) already been generated?
1794      *
1795      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1796      * method rather than calling this method directly.
1797      *
1798      * @param string $thing identifier for the bit of content. Should be of the form
1799      *      frankenstyle_things, e.g. core_course_modchooser.
1800      * @return bool whether that bit of output has been created.
1801      */
1802     public function has_one_time_item_been_created($thing) {
1803         return isset($this->onetimeitemsoutput[$thing]);
1804     }
1805
1806     /**
1807      * Indicate that a particular bit of HTML that is only required once on this
1808      * page (e.g. the contents of the modchooser) has been generated (or is about to be)?
1809      *
1810      * Normally, you can use the {@link should_create_one_time_item_now()} helper
1811      * method rather than calling this method directly.
1812      *
1813      * @param string $thing identifier for the bit of content. Should be of the form
1814      *      frankenstyle_things, e.g. core_course_modchooser.
1815      */
1816     public function set_one_time_item_created($thing) {
1817         if ($this->has_one_time_item_been_created($thing)) {
1818             throw new coding_exception($thing . ' is only supposed to be ouput ' .
1819                     'once per page, but it seems to be being output again.');
1820         }
1821         return $this->onetimeitemsoutput[$thing] = true;
1822     }
1823 }
1824
1825 /**
1826  * This class represents the YUI configuration.
1827  *
1828  * @copyright 2013 Andrew Nicols
1829  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1830  * @since Moodle 2.5
1831  * @package core
1832  * @category output
1833  */
1834 class YUI_config {
1835     /**
1836      * These settings must be public so that when the object is converted to json they are exposed.
1837      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1838      *
1839      * The settings are described and documented in the YUI API at:
1840      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1841      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1842      */
1843     public $debug = false;
1844     public $base;
1845     public $comboBase;
1846     public $combine;
1847     public $filter = null;
1848     public $insertBefore = 'firstthemesheet';
1849     public $groups = array();
1850     public $modules = array();
1851
1852     /**
1853      * @var array List of functions used by the YUI Loader group pattern recognition.
1854      */
1855     protected $jsconfigfunctions = array();
1856
1857     /**
1858      * Create a new group within the YUI_config system.
1859      *
1860      * @param String $name The name of the group. This must be unique and
1861      * not previously used.
1862      * @param Array $config The configuration for this group.
1863      * @return void
1864      */
1865     public function add_group($name, $config) {
1866         if (isset($this->groups[$name])) {
1867             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1868         }
1869         $this->groups[$name] = $config;
1870     }
1871
1872     /**
1873      * Update an existing group configuration
1874      *
1875      * Note, any existing configuration for that group will be wiped out.
1876      * This includes module configuration.
1877      *
1878      * @param String $name The name of the group. This must be unique and
1879      * not previously used.
1880      * @param Array $config The configuration for this group.
1881      * @return void
1882      */
1883     public function update_group($name, $config) {
1884         if (!isset($this->groups[$name])) {
1885             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.');
1886         }
1887         $this->groups[$name] = $config;
1888     }
1889
1890     /**
1891      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1892      *
1893      * Only the body of the function should be passed, and not the whole function wrapper.
1894      *
1895      * The JS function your write will be passed a single argument 'name' containing the
1896      * name of the module being loaded.
1897      *
1898      * @param $function String the body of the JavaScript function. This should be used i
1899      * @return String the name of the function to use in the group pattern configuration.
1900      */
1901     public function set_config_function($function) {
1902         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1903         if (isset($this->jsconfigfunctions[$configname])) {
1904             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1905         }
1906         $this->jsconfigfunctions[$configname] = $function;
1907         return '@' . $configname . '@';
1908     }
1909
1910     /**
1911      * Allow setting of the config function described in {@see set_config_function} from a file.
1912      * The contents of this file are then passed to set_config_function.
1913      *
1914      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1915      *
1916      * @param $file The path to the JavaScript function used for YUI configuration.
1917      * @return String the name of the function to use in the group pattern configuration.
1918      */
1919     public function set_config_source($file) {
1920         global $CFG;
1921         $cache = cache::make('core', 'yuimodules');
1922
1923         // Attempt to get the metadata from the cache.
1924         $keyname = 'configfn_' . $file;
1925         $fullpath = $CFG->dirroot . '/' . $file;
1926         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1927             $cache->delete($keyname);
1928             $configfn = file_get_contents($fullpath);
1929         } else {
1930             $configfn = $cache->get($keyname);
1931             if ($configfn === false) {
1932                 require_once($CFG->libdir . '/jslib.php');
1933                 $configfn = core_minify::js_files(array($fullpath));
1934                 $cache->set($keyname, $configfn);
1935             }
1936         }
1937         return $this->set_config_function($configfn);
1938     }
1939
1940     /**
1941      * Retrieve the list of JavaScript functions for YUI_config groups.
1942      *
1943      * @return String The complete set of config functions
1944      */
1945     public function get_config_functions() {
1946         $configfunctions = '';
1947         foreach ($this->jsconfigfunctions as $functionname => $function) {
1948             $configfunctions .= "var {$functionname} = function(me) {";
1949             $configfunctions .= $function;
1950             $configfunctions .= "};\n";
1951         }
1952         return $configfunctions;
1953     }
1954
1955     /**
1956      * Update the header JavaScript with any required modification for the YUI Loader.
1957      *
1958      * @param $js String The JavaScript to manipulate.
1959      * @return String the modified JS string.
1960      */
1961     public function update_header_js($js) {
1962         // Update the names of the the configFn variables.
1963         // The PHP json_encode function cannot handle literal names so we have to wrap
1964         // them in @ and then replace them with literals of the same function name.
1965         foreach ($this->jsconfigfunctions as $functionname => $function) {
1966             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1967         }
1968         return $js;
1969     }
1970
1971     /**
1972      * Add configuration for a specific module.
1973      *
1974      * @param String $name The name of the module to add configuration for.
1975      * @param Array $config The configuration for the specified module.
1976      * @param String $group The name of the group to add configuration for.
1977      * If not specified, then this module is added to the global
1978      * configuration.
1979      * @return void
1980      */
1981     public function add_module_config($name, $config, $group = null) {
1982         if ($group) {
1983             if (!isset($this->groups[$name])) {
1984                 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.');
1985             }
1986             if (!isset($this->groups[$group]['modules'])) {
1987                 $this->groups[$group]['modules'] = array();
1988             }
1989             $modules = &$this->groups[$group]['modules'];
1990         } else {
1991             $modules = &$this->modules;
1992         }
1993         $modules[$name] = $config;
1994     }
1995
1996     /**
1997      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
1998      *
1999      * If js caching is disabled, metadata will not be served causing YUI to calculate
2000      * module dependencies as each module is loaded.
2001      *
2002      * If metadata does not exist it will be created and stored in a MUC entry.
2003      *
2004      * @return void
2005      */
2006     public function add_moodle_metadata() {
2007         global $CFG;
2008         if (!isset($this->groups['moodle'])) {
2009             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.');
2010         }
2011
2012         if (!isset($this->groups['moodle']['modules'])) {
2013             $this->groups['moodle']['modules'] = array();
2014         }
2015
2016         $cache = cache::make('core', 'yuimodules');
2017         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
2018             $metadata = array();
2019             $metadata = $this->get_moodle_metadata();
2020             $cache->delete('metadata');
2021         } else {
2022             // Attempt to get the metadata from the cache.
2023             if (!$metadata = $cache->get('metadata')) {
2024                 $metadata = $this->get_moodle_metadata();
2025                 $cache->set('metadata', $metadata);
2026             }
2027         }
2028
2029         // Merge with any metadata added specific to this page which was added manually.
2030         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
2031                 $metadata);
2032     }
2033
2034     /**
2035      * Determine the module metadata for all moodle YUI modules.
2036      *
2037      * This works through all modules capable of serving YUI modules, and attempts to get
2038      * metadata for each of those modules.
2039      *
2040      * @return Array of module metadata
2041      */
2042     private function get_moodle_metadata() {
2043         $moodlemodules = array();
2044         // Core isn't a plugin type or subsystem - handle it seperately.
2045         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
2046             $moodlemodules = array_merge($moodlemodules, $module);
2047         }
2048
2049         // Handle other core subsystems.
2050         $subsystems = core_component::get_core_subsystems();
2051         foreach ($subsystems as $subsystem => $path) {
2052             if (is_null($path)) {
2053                 continue;
2054             }
2055             if ($module = $this->get_moodle_path_metadata($path)) {
2056                 $moodlemodules = array_merge($moodlemodules, $module);
2057             }
2058         }
2059
2060         // And finally the plugins.
2061         $plugintypes = core_component::get_plugin_types();
2062         foreach ($plugintypes as $plugintype => $pathroot) {
2063             $pluginlist = core_component::get_plugin_list($plugintype);
2064             foreach ($pluginlist as $plugin => $path) {
2065                 if ($module = $this->get_moodle_path_metadata($path)) {
2066                     $moodlemodules = array_merge($moodlemodules, $module);
2067                 }
2068             }
2069         }
2070
2071         return $moodlemodules;
2072     }
2073
2074     /**
2075      * Helper function process and return the YUI metadata for all of the modules under the specified path.
2076      *
2077      * @param String $path the UNC path to the YUI src directory.
2078      * @return Array the complete array for frankenstyle directory.
2079      */
2080     private function get_moodle_path_metadata($path) {
2081         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
2082         $baseyui = $path . '/yui/src';
2083         $modules = array();
2084         if (is_dir($baseyui)) {
2085             $items = new DirectoryIterator($baseyui);
2086             foreach ($items as $item) {
2087                 if ($item->isDot() or !$item->isDir()) {
2088                     continue;
2089                 }
2090                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
2091                 if (!is_readable($metafile)) {
2092                     continue;
2093                 }
2094                 $metadata = file_get_contents($metafile);
2095                 $modules = array_merge($modules, (array) json_decode($metadata));
2096             }
2097         }
2098         return $modules;
2099     }
2100
2101     /**
2102      * Define YUI modules which we have been required to patch between releases.
2103      *
2104      * We must do this because we aggressively cache content on the browser, and we must also override use of the
2105      * external CDN which will serve the true authoritative copy of the code without our patches.
2106      *
2107      * @param String combobase The local combobase
2108      * @param String yuiversion The current YUI version
2109      * @param Int patchlevel The patch level we're working to for YUI
2110      * @param Array patchedmodules An array containing the names of the patched modules
2111      * @return void
2112      */
2113     public function define_patched_core_modules($combobase, $yuiversion, $patchlevel, $patchedmodules) {
2114         // The version we use is suffixed with a patchlevel so that we can get additional revisions between YUI releases.
2115         $subversion = $yuiversion . '_' . $patchlevel;
2116
2117         if ($this->comboBase == $combobase) {
2118             // If we are using the local combobase in the loader, we can add a group and still make use of the combo
2119             // loader. We just need to specify a different root which includes a slightly different YUI version number
2120             // to include our patchlevel.
2121             $patterns = array();
2122             $modules = array();
2123             foreach ($patchedmodules as $modulename) {
2124                 // We must define the pattern and module here so that the loader uses our group configuration instead of
2125                 // the standard module definition. We may lose some metadata provided by upstream but this will be
2126                 // loaded when the module is loaded anyway.
2127                 $patterns[$modulename] = array(
2128                     'group' => 'yui-patched',
2129                 );
2130                 $modules[$modulename] = array();
2131             }
2132
2133             // Actually add the patch group here.
2134             $this->add_group('yui-patched', array(
2135                 'combine' => true,
2136                 'root' => $subversion . '/',
2137                 'patterns' => $patterns,
2138                 'modules' => $modules,
2139             ));
2140
2141         } else {
2142             // The CDN is in use - we need to instead use the local combobase for this module and override the modules
2143             // definition. We cannot use the local base - we must use the combobase because we cannot invalidate the
2144             // local base in browser caches.
2145             $fullpathbase = $combobase . $subversion . '/';
2146             foreach ($patchedmodules as $modulename) {
2147                 $this->modules[$modulename] = array(
2148                     'fullpath' => $fullpathbase . $modulename . '/' . $modulename . '-min.js'
2149                 );
2150             }
2151         }
2152     }
2153 }
2154
2155 /**
2156  * Invalidate all server and client side template caches.
2157  */
2158 function template_reset_all_caches() {
2159     global $CFG;
2160
2161     $next = time();
2162     if (isset($CFG->templaterev) and $next <= $CFG->templaterev and $CFG->templaterev - $next < 60 * 60) {
2163         // This resolves problems when reset is requested repeatedly within 1s,
2164         // the < 1h condition prevents accidental switching to future dates
2165         // because we might not recover from it.
2166         $next = $CFG->templaterev + 1;
2167     }
2168
2169     set_config('templaterev', $next);
2170 }
2171
2172 /**
2173  * Invalidate all server and client side JS caches.
2174  */
2175 function js_reset_all_caches() {
2176     global $CFG;
2177
2178     $next = time();
2179     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
2180         // This resolves problems when reset is requested repeatedly within 1s,
2181         // the < 1h condition prevents accidental switching to future dates
2182         // because we might not recover from it.
2183         $next = $CFG->jsrev+1;
2184     }
2185
2186     set_config('jsrev', $next);
2187 }