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