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_init_call('M.mod_forum.init_view');
  39  * </pre>
  40  *
  41  * It also supports obsoleted coding style withouth YUI3 modules.
  42  * <pre>
  43  *     $PAGE->requires->css('/mod/mymod/userstyles.php?id='.$id); // not overridable via themes!
  44  *     $PAGE->requires->js('/mod/mymod/script.js');
  45  *     $PAGE->requires->js('/mod/mymod/small_but_urgent.js', true);
  46  *     $PAGE->requires->js_function_call('init_mymod', array($data), true);
  47  * </pre>
  48  *
  49  * There are some natural restrictions on some methods. For example, {@link css()}
  50  * can only be called before the <head> tag is output. See the comments on the
  51  * individual methods for details.
  52  *
  53  * @copyright 2009 Tim Hunt, 2010 Petr Skoda
  54  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  55  * @since Moodle 2.0
  56  * @package core
  57  * @category output
  58  */
  59 class page_requirements_manager {
  60
  61     /**
  62      * @var array List of string available from JS
  63      */
  64     protected $stringsforjs = array();
  65
  66     /**
  67      * @var array List of get_string $a parameters - used for validation only.
  68      */
  69     protected $stringsforjs_as = array();
  70
  71     /**
  72      * @var array List of JS variables to be initialised
  73      */
  74     protected $jsinitvariables = array('head'=>array(), 'footer'=>array());
  75
  76     /**
  77      * @var array Included JS scripts
  78      */
  79     protected $jsincludes = array('head'=>array(), 'footer'=>array());
  80
  81     /**
  82      * @var array List of needed function calls
  83      */
  84     protected $jscalls = array('normal'=>array(), 'ondomready'=>array());
  85
  86     /**
  87      * @var array List of skip links, those are needed for accessibility reasons
  88      */
  89     protected $skiplinks = array();
  90
  91     /**
  92      * @var array Javascript code used for initialisation of page, it should
  93      * be relatively small
  94      */
  95     protected $jsinitcode = array();
  96
  97     /**
  98      * @var array of moodle_url Theme sheets, initialised only from core_renderer
  99      */
 100     protected $cssthemeurls = array();
 101
 102     /**
 103      * @var array of moodle_url List of custom theme sheets, these are strongly discouraged!
 104      * Useful mostly only for CSS submitted by teachers that is not part of the theme.
 105      */
 106     protected $cssurls = array();
 107
 108     /**
 109      * @var array List of requested event handlers
 110      */
 111     protected $eventhandlers = array();
 112
 113     /**
 114      * @var array Extra modules
 115      */
 116     protected $extramodules = array();
 117
 118     /**
 119      * @var bool Flag indicated head stuff already printed
 120      */
 121     protected $headdone = false;
 122
 123     /**
 124      * @var bool Flag indicating top of body already printed
 125      */
 126     protected $topofbodydone = false;
 127
 128     /**
 129      * @var stdClass YUI PHPLoader instance responsible for YUI3 loading from PHP only
 130      */
 131     protected $yui3loader;
 132
 133     /**
 134      * @var YUI_config default YUI loader configuration
 135      */
 136     protected $YUI_config;
 137
 138     /**
 139      * @var array Some config vars exposed in JS, please no secret stuff there
 140      */
 141     protected $M_cfg;
 142
 143     /**
 144      * @var array Stores debug backtraces from when JS modules were included in the page
 145      */
 146     protected $debug_moduleloadstacktraces = array();
 147
 148     /**
 149      * @var array list of requested jQuery plugins
 150      */
 151     protected $jqueryplugins = array();
 152
 153     /**
 154      * @var array list of jQuery plugin overrides
 155      */
 156     protected $jquerypluginoverrides = array();
 157
 158     /**
 159      * Page requirements constructor.
 160      */
 161     public function __construct() {
 162         global $CFG;
 163
 164         // You may need to set up URL rewrite rule because oversized URLs might not be allowed by web server.
 165         $sep = empty($CFG->yuislasharguments) ? '?' : '/';
 166
 167         $this->yui3loader = new stdClass();
 168         $this->YUI_config = new YUI_config();
 169
 170         // Set up some loader options.
 171         if (!empty($CFG->useexternalyui) and strpos($CFG->httpswwwroot, 'https:') !== 0) {
 172             $this->yui3loader->base = 'http://yui.yahooapis.com/' . $CFG->yui3version . '/build/';
 173             $this->yui3loader->comboBase = 'http://yui.yahooapis.com/combo?';
 174         } else {
 175             $this->yui3loader->base = $CFG->httpswwwroot . '/lib/yuilib/'. $CFG->yui3version . '/build/';
 176             $this->yui3loader->comboBase = $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep;
 177         }
 178
 179         // Enable combo loader? This significantly helps with caching and performance!
 180         $this->yui3loader->combine = !empty($CFG->yuicomboloading);
 181
 182         if (empty($CFG->cachejs)) {
 183             $jsrev = -1;
 184         } else if (empty($CFG->jsrev)) {
 185             $jsrev = 1;
 186         } else {
 187             $jsrev = $CFG->jsrev;
 188         }
 189
 190         // Set up JS YUI loader helper object.
 191         $this->YUI_config->base         = $this->yui3loader->base;
 192         $this->YUI_config->comboBase    = $this->yui3loader->comboBase;
 193         $this->YUI_config->combine      = $this->yui3loader->combine;
 194
 195         $configname = $this->YUI_config->set_config_source('lib/yui/config/yui2.js');
 196         $this->YUI_config->add_group('yui2', array(
 197             // Loader configuration for our 2in3, for now ignores $CFG->useexternalyui.
 198             'base' => $CFG->httpswwwroot . '/lib/yuilib/2in3/' . $CFG->yui2version . '/build/',
 199             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep,
 200             'combine' => $this->yui3loader->combine,
 201             'ext' => false,
 202             'root' => '2in3/' . $CFG->yui2version .'/build/',
 203             'patterns' => array(
 204                 'yui2-' => array(
 205                     'group' => 'yui2',
 206                     'configFn' => $configname,
 207                 )
 208             )
 209         ));
 210         $configname = $this->YUI_config->set_config_source('lib/yui/config/moodle.js');
 211         $this->YUI_config->add_group('moodle', array(
 212             'name' => 'moodle',
 213             'base' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep.'moodle/'.$jsrev.'/',
 214             'combine' => $this->yui3loader->combine,
 215             'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep,
 216             'ext' => false,
 217             'root' => 'moodle/'.$jsrev.'/', // Add the rev to the root path so that we can control caching.
 218             'patterns' => array(
 219                 'moodle-' => array(
 220                     'group' => 'moodle',
 221                     'configFn' => $configname,
 222                 )
 223             )
 224         ));
 225
 226         // Set some more loader options applying to groups too.
 227         if (debugging('', DEBUG_DEVELOPER)) {
 228             // When debugging is enabled, we want to load the non-minified (RAW) versions of YUI library modules rather
 229             // than the DEBUG versions as these generally generate too much logging for our purposes.
 230             // However we do want the DEBUG versions of our Moodle-specific modules.
 231             // To debug a YUI-specific issue, change the yui3loader->filter value to DEBUG.
 232             $this->YUI_config->filter = 'RAW';
 233             $this->YUI_config->groups['moodle']['filter'] = 'DEBUG';
 234
 235             // We use the yui3loader->filter setting when writing the YUI3 seed scripts into the header.
 236             $this->yui3loader->filter = $this->YUI_config->filter;
 237             $this->YUI_config->debug = true;
 238         } else {
 239             $this->yui3loader->filter = null;
 240             $this->YUI_config->debug = false;
 241         }
 242
 243         // Add the moodle group's module data.
 244         $this->YUI_config->add_moodle_metadata();
 245
 246         // Every page should include definition of following modules.
 247         $this->js_module($this->find_module('core_filepicker'));
 248     }
 249
 250     /**
 251      * Initialise with the bits of JavaScript that every Moodle page should have.
 252      *
 253      * @param moodle_page $page
 254      * @param core_renderer $renderer
 255      */
 256     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 257         global $CFG;
 258
 259         // JavaScript should always work with $CFG->httpswwwroot rather than $CFG->wwwroot.
 260         // Otherwise, in some situations, users will get warnings about insecure content
 261         // on secure pages from their web browser.
 262
 263         $this->M_cfg = array(
 264             'wwwroot'             => $CFG->httpswwwroot, // Yes, really. See above.
 265             'sesskey'             => sesskey(),
 266             'loadingicon'         => $renderer->pix_url('i/loading_small', 'moodle')->out(false),
 267             'themerev'            => theme_get_revision(),
 268             'slasharguments'      => (int)(!empty($CFG->slasharguments)),
 269             'theme'               => $page->theme->name,
 270             'jsrev'               => ((empty($CFG->cachejs) or empty($CFG->jsrev)) ? -1 : $CFG->jsrev),
 271             'svgicons'            => $page->theme->use_svg_icons()
 272         );
 273         if (debugging('', DEBUG_DEVELOPER)) {
 274             $this->M_cfg['developerdebug'] = true;
 275         }
 276
 277         // Accessibility stuff.
 278         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 279
 280         // Add strings used on many pages.
 281         $this->string_for_js('confirmation', 'admin');
 282         $this->string_for_js('cancel', 'moodle');
 283         $this->string_for_js('yes', 'moodle');
 284
 285         // Alter links in top frame to break out of frames.
 286         if ($page->pagelayout === 'frametop') {
 287             $this->js_init_call('M.util.init_frametop');
 288         }
 289
 290         // Include block drag/drop if editing is on
 291         if ($page->user_is_editing()) {
 292             $params = array(
 293                 'courseid' => $page->course->id,
 294                 'pagetype' => $page->pagetype,
 295                 'pagelayout' => $page->pagelayout,
 296                 'subpage' => $page->subpage,
 297                 'regions' => $page->blocks->get_regions(),
 298                 'contextid' => $page->context->id,
 299             );
 300             if (!empty($page->cm->id)) {
 301                 $params['cmid'] = $page->cm->id;
 302             }
 303             $page->requires->yui_module('moodle-core-blocks', 'M.core_blocks.init_dragdrop', array($params), null, true);
 304         }
 305     }
 306
 307     /**
 308      * Ensure that the specified JavaScript file is linked to from this page.
 309      *
 310      * NOTE: This function is to be used in RARE CASES ONLY, please store your JS in module.js file
 311      * and use $PAGE->requires->js_init_call() instead or use /yui/ subdirectories for YUI modules.
 312      *
 313      * By default the link is put at the end of the page, since this gives best page-load performance.
 314      *
 315      * Even if a particular script is requested more than once, it will only be linked
 316      * to once.
 317      *
 318      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 319      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 320      * @param bool $inhead initialise in head
 321      */
 322     public function js($url, $inhead = false) {
 323         $url = $this->js_fix_url($url);
 324         $where = $inhead ? 'head' : 'footer';
 325         $this->jsincludes[$where][$url->out()] = $url;
 326     }
 327
 328     /**
 329      * Request inclusion of jQuery library in the page.
 330      *
 331      * NOTE: this should not be used in official Moodle distribution!
 332      *
 333      * We are going to bundle jQuery 1.9.x until we drop support
 334      * all support for IE 6-8. Use $PAGE->requires->jquery_plugin('migrate')
 335      * for code written for earlier jQuery versions.
 336      *
 337      * {@see http://docs.moodle.org/dev/jQuery}
 338      */
 339     public function jquery() {
 340         $this->jquery_plugin('jquery');
 341     }
 342
 343     /**
 344      * Request inclusion of jQuery plugin.
 345      *
 346      * NOTE: this should not be used in official Moodle distribution!
 347      *
 348      * jQuery plugins are located in plugin/jquery/* subdirectory,
 349      * plugin/jquery/plugins.php lists all available plugins.
 350      *
 351      * Included core plugins:
 352      *   - jQuery UI
 353      *   - jQuery Migrate (useful for code written for previous UI version)
 354      *
 355      * Add-ons may include extra jQuery plugins in jquery/ directory,
 356      * plugins.php file defines the mapping between plugin names and
 357      * necessary page includes.
 358      *
 359      * Examples:
 360      * <code>
 361      *   // file: mod/xxx/view.php
 362      *   $PAGE->requires->jquery();
 363      *   $PAGE->requires->jquery_plugin('ui');
 364      *   $PAGE->requires->jquery_plugin('ui-css');
 365      * </code>
 366      *
 367      * <code>
 368      *   // file: theme/yyy/lib.php
 369      *   function theme_yyy_page_init(moodle_page $page) {
 370      *       $page->requires->jquery();
 371      *       $page->requires->jquery_plugin('ui');
 372      *       $page->requires->jquery_plugin('ui-css');
 373      *   }
 374      * </code>
 375      *
 376      * <code>
 377      *   // file: blocks/zzz/block_zzz.php
 378      *   public function get_required_javascript() {
 379      *       parent::get_required_javascript();
 380      *       $this->page->requires->jquery();
 381      *       $page->requires->jquery_plugin('ui');
 382      *       $page->requires->jquery_plugin('ui-css');
 383      *   }
 384      * </code>
 385      *
 386      * {@see http://docs.moodle.org/dev/jQuery}
 387      *
 388      * @param string $plugin name of the jQuery plugin as defined in jquery/plugins.php
 389      * @param string $component name of the component
 390      * @return bool success
 391      */
 392     public function jquery_plugin($plugin, $component = 'core') {
 393         global $CFG;
 394
 395         if ($this->headdone) {
 396             debugging('Can not add jQuery plugins after starting page output!');
 397             return false;
 398         }
 399
 400         if ($component !== 'core' and in_array($plugin, array('jquery', 'ui', 'ui-css', 'migrate'))) {
 401             debugging("jQuery plugin '$plugin' is included in Moodle core, other components can not use the same name.", DEBUG_DEVELOPER);
 402             $component = 'core';
 403         } else if ($component !== 'core' and strpos($component, '_') === false) {
 404             // Let's normalise the legacy activity names, Frankenstyle rulez!
 405             $component = 'mod_' . $component;
 406         }
 407
 408         if (empty($this->jqueryplugins) and ($component !== 'core' or $plugin !== 'jquery')) {
 409             // Make sure the jQuery itself is always loaded first,
 410             // the order of all other plugins depends on order of $PAGE_>requires->.
 411             $this->jquery_plugin('jquery', 'core');
 412         }
 413
 414         if (isset($this->jqueryplugins[$plugin])) {
 415             // No problem, we already have something, first Moodle plugin to register the jQuery plugin wins.
 416             return true;
 417         }
 418
 419         $componentdir = core_component::get_component_directory($component);
 420         if (!file_exists($componentdir) or !file_exists("$componentdir/jquery/plugins.php")) {
 421             debugging("Can not load jQuery plugin '$plugin', missing plugins.php in component '$component'.", DEBUG_DEVELOPER);
 422             return false;
 423         }
 424
 425         $plugins = array();
 426         require("$componentdir/jquery/plugins.php");
 427
 428         if (!isset($plugins[$plugin])) {
 429             debugging("jQuery plugin '$plugin' can not be found in component '$component'.", DEBUG_DEVELOPER);
 430             return false;
 431         }
 432
 433         $this->jqueryplugins[$plugin] = new stdClass();
 434         $this->jqueryplugins[$plugin]->plugin    = $plugin;
 435         $this->jqueryplugins[$plugin]->component = $component;
 436         $this->jqueryplugins[$plugin]->urls      = array();
 437
 438         foreach ($plugins[$plugin]['files'] as $file) {
 439             if (debugging('', DEBUG_DEVELOPER)) {
 440                 if (!file_exists("$componentdir/jquery/$file")) {
 441                     debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 442                     continue;
 443                 }
 444                 $file = str_replace('.min.css', '.css', $file);
 445                 $file = str_replace('.min.js', '.js', $file);
 446             }
 447             if (!file_exists("$componentdir/jquery/$file")) {
 448                 debugging("Invalid file '$file' specified in jQuery plugin '$plugin' in component '$component'");
 449                 continue;
 450             }
 451             if (!empty($CFG->slasharguments)) {
 452                 $url = new moodle_url("$CFG->httpswwwroot/theme/jquery.php");
 453                 $url->set_slashargument("/$component/$file");
 454
 455             } else {
 456                 // This is not really good, we need slasharguments for relative links, this means no caching...
 457                 $path = realpath("$componentdir/jquery/$file");
 458                 if (strpos($path, $CFG->dirroot) === 0) {
 459                     $url = $CFG->httpswwwroot.preg_replace('/^'.preg_quote($CFG->dirroot, '/').'/', '', $path);
 460                     $url = new moodle_url($url);
 461                 } else {
 462                     // Bad luck, fix your server!
 463                     debugging("Moodle jQuery integration requires 'slasharguments' setting to be enabled.");
 464                     continue;
 465                 }
 466             }
 467             $this->jqueryplugins[$plugin]->urls[] = $url;
 468         }
 469
 470         return true;
 471     }
 472
 473     /**
 474      * Request replacement of one jQuery plugin by another.
 475      *
 476      * This is useful when themes want to replace the jQuery UI theme,
 477      * the problem is that theme can not prevent others from including the core ui-css plugin.
 478      *
 479      * Example:
 480      *  1/ generate new jQuery UI theme and place it into theme/yourtheme/jquery/
 481      *  2/ write theme/yourtheme/jquery/plugins.php
 482      *  3/ init jQuery from theme
 483      *
 484      * <code>
 485      *   // file theme/yourtheme/lib.php
 486      *   function theme_yourtheme_page_init($page) {
 487      *       $page->requires->jquery_plugin('yourtheme-ui-css', 'theme_yourtheme');
 488      *       $page->requires->jquery_override_plugin('ui-css', 'yourtheme-ui-css');
 489      *   }
 490      * </code>
 491      *
 492      * This code prevents loading of standard 'ui-css' which my be requested by other plugins,
 493      * the 'yourtheme-ui-css' gets loaded only if some other code requires jquery.
 494      *
 495      * {@see http://docs.moodle.org/dev/jQuery}
 496      *
 497      * @param string $oldplugin original plugin
 498      * @param string $newplugin the replacement
 499      */
 500     public function jquery_override_plugin($oldplugin, $newplugin) {
 501         if ($this->headdone) {
 502             debugging('Can not override jQuery plugins after starting page output!');
 503             return;
 504         }
 505         $this->jquerypluginoverrides[$oldplugin] = $newplugin;
 506     }
 507
 508     /**
 509      * Return jQuery related markup for page start.
 510      * @return string
 511      */
 512     protected function get_jquery_headcode() {
 513         if (empty($this->jqueryplugins['jquery'])) {
 514             // If nobody requested jQuery then do not bother to load anything.
 515             // This may be useful for themes that want to override 'ui-css' only if requested by something else.
 516             return '';
 517         }
 518
 519         $included = array();
 520         $urls = array();
 521
 522         foreach ($this->jqueryplugins as $name => $unused) {
 523             if (isset($included[$name])) {
 524                 continue;
 525             }
 526             if (array_key_exists($name, $this->jquerypluginoverrides)) {
 527                 // The following loop tries to resolve the replacements,
 528                 // use max 100 iterations to prevent infinite loop resulting
 529                 // in blank page.
 530                 $cyclic = true;
 531                 $oldname = $name;
 532                 for ($i=0; $i<100; $i++) {
 533                     $name = $this->jquerypluginoverrides[$name];
 534                     if (!array_key_exists($name, $this->jquerypluginoverrides)) {
 535                         $cyclic = false;
 536                         break;
 537                     }
 538                 }
 539                 if ($cyclic) {
 540                     // We can not do much with cyclic references here, let's use the old plugin.
 541                     $name = $oldname;
 542                     debugging("Cyclic overrides detected for jQuery plugin '$name'");
 543
 544                 } else if (empty($name)) {
 545                     // Developer requested removal of the plugin.
 546                     continue;
 547
 548                 } else if (!isset($this->jqueryplugins[$name])) {
 549                     debugging("Unknown jQuery override plugin '$name' detected");
 550                     $name = $oldname;
 551
 552                 } else if (isset($included[$name])) {
 553                     // The plugin was already included, easy.
 554                     continue;
 555                 }
 556             }
 557
 558             $plugin = $this->jqueryplugins[$name];
 559             $urls = array_merge($urls, $plugin->urls);
 560             $included[$name] = true;
 561         }
 562
 563         $output = '';
 564         $attributes = array('rel' => 'stylesheet', 'type' => 'text/css');
 565         foreach ($urls as $url) {
 566             if (preg_match('/\.js$/', $url)) {
 567                 $output .= html_writer::script('', $url);
 568             } else if (preg_match('/\.css$/', $url)) {
 569                 $attributes['href'] = $url;
 570                 $output .= html_writer::empty_tag('link', $attributes) . "\n";
 571             }
 572         }
 573
 574         return $output;
 575     }
 576
 577     /**
 578      * This method was used to load YUI2 libraries into global scope,
 579      * use YUI 2in3 instead. Every YUI2 module is represented as a yui2-*
 580      * sandboxed module in YUI3 code via Y.YUI2. property.
 581      *
 582      * {@see http://tracker.moodle.org/browse/MDL-34741}
 583      *
 584      * @param string|array $libname
 585      * @deprecated since 2.4
 586      */
 587     public function yui2_lib($libname) {
 588         throw new coding_exception('PAGE->yui2_lib() is not available any more, use YUI 2in3 instead, see MDL-34741 for more information.');
 589     }
 590
 591     /**
 592      * Returns the actual url through which a script is served.
 593      *
 594      * @param moodle_url|string $url full moodle url, or shortened path to script
 595      * @return moodle_url
 596      */
 597     protected function js_fix_url($url) {
 598         global $CFG;
 599
 600         if ($url instanceof moodle_url) {
 601             return $url;
 602         } else if (strpos($url, '/') === 0) {
 603             // Fix the admin links if needed.
 604             if ($CFG->admin !== 'admin') {
 605                 if (strpos($url, "/admin/") === 0) {
 606                     $url = preg_replace("|^/admin/|", "/$CFG->admin/", $url);
 607                 }
 608             }
 609             if (debugging()) {
 610                 // Check file existence only when in debug mode.
 611                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 612                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 613                 }
 614             }
 615             if (substr($url, -3) === '.js') {
 616                 if (empty($CFG->cachejs) or !isset($CFG->jsrev)) {
 617                     $jsrev = -1;
 618                 } else {
 619                     $jsrev = (int)$CFG->jsrev;
 620                 }
 621                 if (empty($CFG->slasharguments)) {
 622                     return new moodle_url($CFG->httpswwwroot.'/lib/javascript.php', array('rev'=>$jsrev, 'jsfile'=>$url));
 623                 } else {
 624                     $returnurl = new moodle_url($CFG->httpswwwroot.'/lib/javascript.php');
 625                     $returnurl->set_slashargument('/'.$jsrev.$url);
 626                     return $returnurl;
 627                 }
 628             } else {
 629                 return new moodle_url($CFG->httpswwwroot.$url);
 630             }
 631         } else {
 632             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 633         }
 634     }
 635
 636     /**
 637      * Find out if JS module present and return details.
 638      *
 639      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 640      * @return array description of module or null if not found
 641      */
 642     protected function find_module($component) {
 643         global $CFG, $PAGE;
 644
 645         $module = null;
 646
 647         if (strpos($component, 'core_') === 0) {
 648             // Must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 649             // so that we do nto have to repeat the definition of these modules over and over again.
 650             switch($component) {
 651                 case 'core_filepicker':
 652                     $module = array('name'     => 'core_filepicker',
 653                                     'fullpath' => '/repository/filepicker.js',
 654                                     'requires' => array('base', 'node', 'node-event-simulate', 'json', 'async-queue', 'io-base', 'io-upload-iframe', 'io-form', 'yui2-treeview', 'panel', 'cookie', 'datatable', 'datatable-sort', 'resize-plugin', 'dd-plugin', 'escape', 'moodle-core_filepicker'),
 655                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 656                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 657                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 658                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 659                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 660                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 661                                                         array('referencesexist', 'repository')
 662                                                     ));
 663                     break;
 664                 case 'core_comment':
 665                     $module = array('name'     => 'core_comment',
 666                                     'fullpath' => '/comment/comment.js',
 667                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay'),
 668                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 669                                 );
 670                     break;
 671                 case 'core_role':
 672                     $module = array('name'     => 'core_role',
 673                                     'fullpath' => '/admin/roles/module.js',
 674                                     'requires' => array('node', 'cookie'));
 675                     break;
 676                 case 'core_completion':
 677                     $module = array('name'     => 'core_completion',
 678                                     'fullpath' => '/course/completion.js');
 679                     break;
 680                 case 'core_message':
 681                     $module = array('name'     => 'core_message',
 682                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 683                                     'fullpath' => '/message/module.js');
 684                     break;
 685                 case 'core_group':
 686                     $module = array('name'     => 'core_group',
 687                                     'fullpath' => '/group/module.js',
 688                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 689                     break;
 690                 case 'core_question_engine':
 691                     $module = array('name'     => 'core_question_engine',
 692                                     'fullpath' => '/question/qengine.js',
 693                                     'requires' => array('node', 'event'));
 694                     break;
 695                 case 'core_rating':
 696                     $module = array('name'     => 'core_rating',
 697                                     'fullpath' => '/rating/module.js',
 698                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 699                     break;
 700                 case 'core_dndupload':
 701                     $module = array('name'     => 'core_dndupload',
 702                                     'fullpath' => '/lib/form/dndupload.js',
 703                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 704                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'),
 705                                                         array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle'), array('maxbytesforfile', 'moodle'),
 706                                                         array('maxareabytesreached', 'moodle')
 707                                                     ));
 708                     break;
 709             }
 710
 711         } else {
 712             if ($dir = core_component::get_component_directory($component)) {
 713                 if (file_exists("$dir/module.js")) {
 714                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 715                         $dir = substr($dir, strlen($CFG->dirroot));
 716                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 717                     }
 718                 }
 719             }
 720         }
 721
 722         return $module;
 723     }
 724
 725     /**
 726      * Append YUI3 module to default YUI3 JS loader.
 727      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 728      *
 729      * @param string|array $module name of module (details are autodetected), or full module specification as array
 730      * @return void
 731      */
 732     public function js_module($module) {
 733         global $CFG;
 734
 735         if (empty($module)) {
 736             throw new coding_exception('Missing YUI3 module name or full description.');
 737         }
 738
 739         if (is_string($module)) {
 740             $module = $this->find_module($module);
 741         }
 742
 743         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 744             throw new coding_exception('Missing YUI3 module details.');
 745         }
 746
 747         // Don't load this module if we already have, no need to!
 748         if ($this->js_module_loaded($module['name'])) {
 749             if (debugging('', DEBUG_DEVELOPER)) {
 750                 $this->debug_moduleloadstacktraces[$module['name']][] = format_backtrace(debug_backtrace());
 751             }
 752             return;
 753         }
 754
 755         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 756         // Add all needed strings.
 757         if (!empty($module['strings'])) {
 758             foreach ($module['strings'] as $string) {
 759                 $identifier = $string[0];
 760                 $component = isset($string[1]) ? $string[1] : 'moodle';
 761                 $a = isset($string[2]) ? $string[2] : null;
 762                 $this->string_for_js($identifier, $component, $a);
 763             }
 764         }
 765         unset($module['strings']);
 766
 767         // Process module requirements and attempt to load each. This allows
 768         // moodle modules to require each other.
 769         if (!empty($module['requires'])){
 770             foreach ($module['requires'] as $requirement) {
 771                 $rmodule = $this->find_module($requirement);
 772                 if (is_array($rmodule)) {
 773                     $this->js_module($rmodule);
 774                 }
 775             }
 776         }
 777
 778         if ($this->headdone) {
 779             $this->extramodules[$module['name']] = $module;
 780         } else {
 781             $this->YUI_config->add_module_config($module['name'], $module);
 782         }
 783         if (debugging('', DEBUG_DEVELOPER)) {
 784             if (!array_key_exists($module['name'], $this->debug_moduleloadstacktraces)) {
 785                 $this->debug_moduleloadstacktraces[$module['name']] = array();
 786             }
 787             $this->debug_moduleloadstacktraces[$module['name']][] = format_backtrace(debug_backtrace());
 788         }
 789     }
 790
 791     /**
 792      * Returns true if the module has already been loaded.
 793      *
 794      * @param string|array $module
 795      * @return bool True if the module has already been loaded
 796      */
 797     protected function js_module_loaded($module) {
 798         if (is_string($module)) {
 799             $modulename = $module;
 800         } else {
 801             $modulename = $module['name'];
 802         }
 803         return array_key_exists($modulename, $this->YUI_config->modules) ||
 804                array_key_exists($modulename, $this->extramodules);
 805     }
 806
 807     /**
 808      * Returns the stacktraces from loading js modules.
 809      * @return array
 810      */
 811     public function get_loaded_modules() {
 812         return $this->debug_moduleloadstacktraces;
 813     }
 814
 815     /**
 816      * Ensure that the specified CSS file is linked to from this page.
 817      *
 818      * Because stylesheet links must go in the <head> part of the HTML, you must call
 819      * this function before {@link get_head_code()} is called. That normally means before
 820      * the call to print_header. If you call it when it is too late, an exception
 821      * will be thrown.
 822      *
 823      * Even if a particular style sheet is requested more than once, it will only
 824      * be linked to once.
 825      *
 826      * Please note use of this feature is strongly discouraged,
 827      * it is suitable only for places where CSS is submitted directly by teachers.
 828      * (Students must not be allowed to submit any external CSS because it may
 829      * contain embedded javascript!). Example of correct use is mod/data.
 830      *
 831      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 832      *   For example:
 833      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 834      */
 835     public function css($stylesheet) {
 836         global $CFG;
 837
 838         if ($this->headdone) {
 839             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 840         }
 841
 842         if ($stylesheet instanceof moodle_url) {
 843             // ok
 844         } else if (strpos($stylesheet, '/') === 0) {
 845             $stylesheet = new moodle_url($CFG->httpswwwroot.$stylesheet);
 846         } else {
 847             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 848         }
 849
 850         $this->cssurls[$stylesheet->out()] = $stylesheet;
 851     }
 852
 853     /**
 854      * Add theme stylesheet to page - do not use from plugin code,
 855      * this should be called only from the core renderer!
 856      *
 857      * @param moodle_url $stylesheet
 858      * @return void
 859      */
 860     public function css_theme(moodle_url $stylesheet) {
 861         $this->cssthemeurls[] = $stylesheet;
 862     }
 863
 864     /**
 865      * Ensure that a skip link to a given target is printed at the top of the <body>.
 866      *
 867      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 868      * will be thrown). That normally means you must call this before the call to print_header.
 869      *
 870      * If you ask for a particular skip link to be printed, it is then your responsibility
 871      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 872      * page, so that the skip link goes somewhere.
 873      *
 874      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 875      *
 876      * @param string $target the name of anchor this link should go to. For example 'maincontent'.
 877      * @param string $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 878      */
 879     public function skip_link_to($target, $linktext) {
 880         if ($this->topofbodydone) {
 881             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 882             return;
 883         }
 884         $this->skiplinks[$target] = $linktext;
 885     }
 886
 887     /**
 888      * !!!DEPRECATED!!! please use js_init_call() if possible
 889      * Ensure that the specified JavaScript function is called from an inline script
 890      * somewhere on this page.
 891      *
 892      * By default the call will be put in a script tag at the
 893      * end of the page after initialising Y instance, since this gives best page-load
 894      * performance and allows you to use YUI3 library.
 895      *
 896      * If you request that a particular function is called several times, then
 897      * that is what will happen (unlike linking to a CSS or JS file, where only
 898      * one link will be output).
 899      *
 900      * The main benefit of the method is the automatic encoding of all function parameters.
 901      *
 902      * @deprecated
 903      *
 904      * @param string $function the name of the JavaScritp function to call. Can
 905      *      be a compound name like 'Y.Event.purgeElement'. Can also be
 906      *      used to create and object by using a 'function name' like 'new user_selector'.
 907      * @param array $arguments and array of arguments to be passed to the function.
 908      *      When generating the function call, this will be escaped using json_encode,
 909      *      so passing objects and arrays should work.
 910      * @param bool $ondomready If tru the function is only called when the dom is
 911      *      ready for manipulation.
 912      * @param int $delay The delay before the function is called.
 913      */
 914     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
 915         $where = $ondomready ? 'ondomready' : 'normal';
 916         $this->jscalls[$where][] = array($function, $arguments, $delay);
 917     }
 918
 919     /**
 920      * Adds a call to make use of a YUI gallery module. DEPRECATED DO NOT USE!!!
 921      *
 922      * @deprecated DO NOT USE
 923      *
 924      * @param string|array $modules One or more gallery modules to require
 925      * @param string $version
 926      * @param string $function
 927      * @param array $arguments
 928      * @param bool $ondomready
 929      */
 930     public function js_gallery_module($modules, $version, $function, array $arguments = null, $ondomready = false) {
 931         global $CFG;
 932         debugging('This function will be removed before 2.0 is released please change it from js_gallery_module to yui_module', DEBUG_DEVELOPER);
 933         $this->yui_module($modules, $function, $arguments, $version, $ondomready);
 934     }
 935
 936     /**
 937      * Creates a JavaScript function call that requires one or more modules to be loaded.
 938      *
 939      * This function can be used to include all of the standard YUI module types within JavaScript:
 940      *     - YUI3 modules    [node, event, io]
 941      *     - YUI2 modules    [yui2-*]
 942      *     - Moodle modules  [moodle-*]
 943      *     - Gallery modules [gallery-*]
 944      *
 945      * @param array|string $modules One or more modules
 946      * @param string $function The function to call once modules have been loaded
 947      * @param array $arguments An array of arguments to pass to the function
 948      * @param string $galleryversion The gallery version to use
 949      * @param bool $ondomready
 950      */
 951     public function yui_module($modules, $function, array $arguments = null, $galleryversion = null, $ondomready = false) {
 952         global $CFG;
 953
 954         if (!$galleryversion) {
 955             $galleryversion = '2010.04.08-12-35';
 956         }
 957
 958         if (!is_array($modules)) {
 959             $modules = array($modules);
 960         }
 961         if (empty($CFG->useexternalyui)) {
 962             // We need to set the M.yui.galleryversion to the correct version
 963             $jscode = 'M.yui.galleryversion='.json_encode($galleryversion).';';
 964         } else {
 965             // Set Y's config.gallery to the version
 966             $jscode = 'Y.config.gallery='.json_encode($galleryversion).';';
 967         }
 968         $jscode .= 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
 969         if ($ondomready) {
 970             $jscode = "Y.on('domready', function() { $jscode });";
 971         }
 972         $this->jsinitcode[] = $jscode;
 973     }
 974
 975     /**
 976      * Ensure that the specified JavaScript function is called from an inline script
 977      * from page footer.
 978      *
 979      * @param string $function the name of the JavaScritp function to with init code,
 980      *      usually something like 'M.mod_mymodule.init'
 981      * @param array $extraarguments and array of arguments to be passed to the function.
 982      *      The first argument is always the YUI3 Y instance with all required dependencies
 983      *      already loaded.
 984      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
 985      * @param array $module JS module specification array
 986      */
 987     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
 988         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
 989         if (!$module) {
 990             // Detect module automatically.
 991             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
 992                 $module = $this->find_module($matches[1]);
 993             }
 994         }
 995
 996         $this->js_init_code($jscode, $ondomready, $module);
 997     }
 998
 999     /**
1000      * Add short static javascript code fragment to page footer.
1001      * This is intended primarily for loading of js modules and initialising page layout.
1002      * Ideally the JS code fragment should be stored in plugin renderer so that themes
1003      * may override it.
1004      *
1005      * @param string $jscode
1006      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
1007      * @param array $module JS module specification array
1008      */
1009     public function js_init_code($jscode, $ondomready = false, array $module = null) {
1010         $jscode = trim($jscode, " ;\n"). ';';
1011
1012         if ($module) {
1013             $this->js_module($module);
1014             $modulename = $module['name'];
1015             $jscode = "Y.use('$modulename', function(Y) { $jscode });";
1016         }
1017
1018         if ($ondomready) {
1019             $jscode = "Y.on('domready', function() { $jscode });";
1020         }
1021
1022         $this->jsinitcode[] = $jscode;
1023     }
1024
1025     /**
1026      * Make a language string available to JavaScript.
1027      *
1028      * All the strings will be available in a M.str object in the global namespace.
1029      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
1030      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
1031      * equivalent in the current language.
1032      *
1033      * The arguments to this function are just like the arguments to get_string
1034      * except that $component is not optional, and there are some aspects to consider
1035      * when the string contains {$a} placeholder.
1036      *
1037      * If the string does not contain any {$a} placeholder, you can simply use
1038      * M.str.component.identifier to obtain it. If you prefer, you can call
1039      * M.util.get_string(identifier, component) to get the same result.
1040      *
1041      * If you need to use {$a} placeholders, there are two options. Either the
1042      * placeholder should be substituted in PHP on server side or it should
1043      * be substituted in Javascript at client side.
1044      *
1045      * To substitute the placeholder at server side, just provide the required
1046      * value for the placeholder when you require the string. Because each string
1047      * is only stored once in the JavaScript (based on $identifier and $module)
1048      * you cannot get the same string with two different values of $a. If you try,
1049      * an exception will be thrown. Once the placeholder is substituted, you can
1050      * use M.str or M.util.get_string() as shown above:
1051      *
1052      *     // Require the string in PHP and replace the placeholder.
1053      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
1054      *     // Use the result of the substitution in Javascript.
1055      *     alert(M.str.moodle.fullnamedisplay);
1056      *
1057      * To substitute the placeholder at client side, use M.util.get_string()
1058      * function. It implements the same logic as {@link get_string()}:
1059      *
1060      *     // Require the string in PHP but keep {$a} as it is.
1061      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
1062      *     // Provide the values on the fly in Javascript.
1063      *     user = { firstname : 'Harry', lastname : 'Potter' }
1064      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
1065      *
1066      * If you do need the same string expanded with different $a values in PHP
1067      * on server side, then the solution is to put them in your own data structure
1068      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
1069      *
1070      * @param string $identifier the desired string.
1071      * @param string $component the language file to look in.
1072      * @param mixed $a any extra data to add into the string (optional).
1073      */
1074     public function string_for_js($identifier, $component, $a = null) {
1075         if (!$component) {
1076             throw new coding_exception('The $component parameter is required for page_requirements_manager::string_for_js().');
1077         }
1078         if (isset($this->stringsforjs_as[$component][$identifier]) and $this->stringsforjs_as[$component][$identifier] !== $a) {
1079             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
1080                     "from lang file '$component' with different \$a parameter?");
1081         }
1082         if (!isset($this->stringsforjs[$component][$identifier])) {
1083             $this->stringsforjs[$component][$identifier] = new lang_string($identifier, $component, $a);
1084             $this->stringsforjs_as[$component][$identifier] = $a;
1085         }
1086     }
1087
1088     /**
1089      * Make an array of language strings available for JS.
1090      *
1091      * This function calls the above function {@link string_for_js()} for each requested
1092      * string in the $identifiers array that is passed to the argument for a single module
1093      * passed in $module.
1094      *
1095      * <code>
1096      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
1097      *
1098      * // The above is identical to calling:
1099      *
1100      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
1101      * $PAGE->requires->string_for_js('two', 'mymod');
1102      * $PAGE->requires->string_for_js('three', 'mymod', 3);
1103      * </code>
1104      *
1105      * @param array $identifiers An array of desired strings
1106      * @param string $component The module to load for
1107      * @param mixed $a This can either be a single variable that gets passed as extra
1108      *         information for every string or it can be an array of mixed data where the
1109      *         key for the data matches that of the identifier it is meant for.
1110      *
1111      */
1112     public function strings_for_js($identifiers, $component, $a = null) {
1113         foreach ($identifiers as $key => $identifier) {
1114             if (is_array($a) && array_key_exists($key, $a)) {
1115                 $extra = $a[$key];
1116             } else {
1117                 $extra = $a;
1118             }
1119             $this->string_for_js($identifier, $component, $extra);
1120         }
1121     }
1122
1123     /**
1124      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
1125      *
1126      * Make some data from PHP available to JavaScript code.
1127      *
1128      * For example, if you call
1129      * <pre>
1130      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
1131      * </pre>
1132      * then in JavsScript mydata.name will be 'Moodle'.
1133      *
1134      * @deprecated
1135      * @param string $variable the the name of the JavaScript variable to assign the data to.
1136      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
1137      *      should be considered an experimental feature.
1138      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
1139      *      so passing objects and arrays should work.
1140      * @param bool $inhead initialise in head
1141      * @return void
1142      */
1143     public function data_for_js($variable, $data, $inhead=false) {
1144         $where = $inhead ? 'head' : 'footer';
1145         $this->jsinitvariables[$where][] = array($variable, $data);
1146     }
1147
1148     /**
1149      * Creates a YUI event handler.
1150      *
1151      * @param mixed $selector standard YUI selector for elements, may be array or string, element id is in the form "#idvalue"
1152      * @param string $event A valid DOM event (click, mousedown, change etc.)
1153      * @param string $function The name of the function to call
1154      * @param array  $arguments An optional array of argument parameters to pass to the function
1155      */
1156     public function event_handler($selector, $event, $function, array $arguments = null) {
1157         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
1158     }
1159
1160     /**
1161      * Returns code needed for registering of event handlers.
1162      * @return string JS code
1163      */
1164     protected function get_event_handler_code() {
1165         $output = '';
1166         foreach ($this->eventhandlers as $h) {
1167             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
1168         }
1169         return $output;
1170     }
1171
1172     /**
1173      * Get the inline JavaScript code that need to appear in a particular place.
1174      * @param bool $ondomready
1175      * @return string
1176      */
1177     protected function get_javascript_code($ondomready) {
1178         $where = $ondomready ? 'ondomready' : 'normal';
1179         $output = '';
1180         if ($this->jscalls[$where]) {
1181             foreach ($this->jscalls[$where] as $data) {
1182                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
1183             }
1184             if (!empty($ondomready)) {
1185                 $output = "    Y.on('domready', function() {\n$output\n    });";
1186             }
1187         }
1188         return $output;
1189     }
1190
1191     /**
1192      * Returns js code to be executed when Y is available.
1193      * @return string
1194      */
1195     protected function get_javascript_init_code() {
1196         if (count($this->jsinitcode)) {
1197             return implode("\n", $this->jsinitcode) . "\n";
1198         }
1199         return '';
1200     }
1201
1202     /**
1203      * Returns basic YUI3 JS loading code.
1204      * YUI3 is using autoloading of both CSS and JS code.
1205      *
1206      * Major benefit of this compared to standard js/csss loader is much improved
1207      * caching, better browser cache utilisation, much fewer http requests.
1208      *
1209      * @param moodle_page $page
1210      * @return string
1211      */
1212     protected function get_yui3lib_headcode($page) {
1213         global $CFG;
1214
1215         $code = '';
1216
1217         if ($this->yui3loader->combine) {
1218             if (!empty($page->theme->yuicssmodules)) {
1219                 $modules = array();
1220                 foreach ($page->theme->yuicssmodules as $module) {
1221                     $modules[] = "$CFG->yui3version/build/$module/$module-min.css";
1222                 }
1223                 $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase.implode('&amp;', $modules).'" />';
1224             }
1225             $code .= '<script type="text/javascript" src="'.$this->yui3loader->comboBase
1226                      .$CFG->yui3version.'/build/simpleyui/simpleyui-min.js&amp;'
1227                      .$CFG->yui3version.'/build/loader/loader-min.js"></script>';
1228         } else {
1229             if (!empty($page->theme->yuicssmodules)) {
1230                 foreach ($page->theme->yuicssmodules as $module) {
1231                     $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.$module.'/'.$module.'-min.css" />';
1232                 }
1233             }
1234             $code .= '<script type="text/javascript" src="'.$this->yui3loader->base.'simpleyui/simpleyui-min.js"></script>';
1235             $code .= '<script type="text/javascript" src="'.$this->yui3loader->base.'loader/loader-min.js"></script>';
1236         }
1237
1238
1239         if ($this->yui3loader->filter === 'RAW') {
1240             $code = str_replace('-min.css', '.css', $code);
1241             $code = str_replace('-min.js', '.js', $code);
1242         } else if ($this->yui3loader->filter === 'DEBUG') {
1243             $code = str_replace('-min.css', '.css', $code);
1244             $code = str_replace('-min.js', '-debug.js', $code);
1245         }
1246
1247         return $code;
1248     }
1249
1250     /**
1251      * Returns html tags needed for inclusion of theme CSS.
1252      *
1253      * @return string
1254      */
1255     protected function get_css_code() {
1256         // First of all the theme CSS, then any custom CSS
1257         // Please note custom CSS is strongly discouraged,
1258         // because it can not be overridden by themes!
1259         // It is suitable only for things like mod/data which accepts CSS from teachers.
1260         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1261
1262         // This line of code may look funny but it is currently required in order
1263         // to avoid MASSIVE display issues in Internet Explorer.
1264         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1265         // ignored whenever another resource is added until such time as a redraw
1266         // is forced, usually by moving the mouse over the affected element.
1267         $code = html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1268
1269         $urls = $this->cssthemeurls + $this->cssurls;
1270         foreach ($urls as $url) {
1271             $attributes['href'] = $url;
1272             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1273             // This id is needed in first sheet only so that theme may override YUI sheets loaded on the fly.
1274             unset($attributes['id']);
1275         }
1276
1277         return $code;
1278     }
1279
1280     /**
1281      * Adds extra modules specified after printing of page header.
1282      *
1283      * @return string
1284      */
1285     protected function get_extra_modules_code() {
1286         if (empty($this->extramodules)) {
1287             return '';
1288         }
1289         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1290     }
1291
1292     /**
1293      * Generate any HTML that needs to go inside the <head> tag.
1294      *
1295      * Normally, this method is called automatically by the code that prints the
1296      * <head> tag. You should not normally need to call it in your own code.
1297      *
1298      * @param moodle_page $page
1299      * @param core_renderer $renderer
1300      * @return string the HTML code to to inside the <head> tag.
1301      */
1302     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1303         global $CFG;
1304
1305         // Note: the $page and $output are not stored here because it would
1306         // create circular references in memory which prevents garbage collection.
1307         $this->init_requirements_data($page, $renderer);
1308
1309         $output = '';
1310
1311         // Set up the M namespace.
1312         $js = "var M = {}; M.yui = {};\n";
1313
1314         // Capture the time now ASAP during page load. This minimises the lag when
1315         // we try to relate times on the server to times in the browser.
1316         // An example of where this is used is the quiz countdown timer.
1317         $js .= "M.pageloadstarttime = new Date();\n";
1318
1319         // Add a subset of Moodle configuration to the M namespace.
1320         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1321
1322         // Set up global YUI3 loader object - this should contain all code needed by plugins.
1323         // Note: in JavaScript just use "YUI().use('overlay', function(Y) { .... });",
1324         //       this needs to be done before including any other script.
1325         $js .= $this->YUI_config->get_config_functions();
1326         $js .= js_writer::set_variable('YUI_config', $this->YUI_config, false) . "\n";
1327         $js .= "M.yui.loader = {modules: {}};\n"; // Backwards compatibility only, not used any more.
1328         $js = $this->YUI_config->update_header_js($js);
1329
1330         $output .= html_writer::script($js);
1331
1332         // YUI3 JS and CSS need to be loaded in the header but after the YUI_config has been created.
1333         // They should be cached well by the browser.
1334         $output .= $this->get_yui3lib_headcode($page);
1335
1336         // Add hacked jQuery support, it is not intended for standard Moodle distribution!
1337         $output .= $this->get_jquery_headcode();
1338
1339         // Now theme CSS + custom CSS in this specific order.
1340         $output .= $this->get_css_code();
1341
1342         // Link our main JS file, all core stuff should be there.
1343         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1344
1345         // Add variables.
1346         if ($this->jsinitvariables['head']) {
1347             $js = '';
1348             foreach ($this->jsinitvariables['head'] as $data) {
1349                 list($var, $value) = $data;
1350                 $js .= js_writer::set_variable($var, $value, true);
1351             }
1352             $output .= html_writer::script($js);
1353         }
1354
1355         // All the other linked things from HEAD - there should be as few as possible.
1356         if ($this->jsincludes['head']) {
1357             foreach ($this->jsincludes['head'] as $url) {
1358                 $output .= html_writer::script('', $url);
1359             }
1360         }
1361
1362         // Mark head sending done, it is not possible to anything there.
1363         $this->headdone = true;
1364
1365         return $output;
1366     }
1367
1368     /**
1369      * Generate any HTML that needs to go at the start of the <body> tag.
1370      *
1371      * Normally, this method is called automatically by the code that prints the
1372      * <head> tag. You should not normally need to call it in your own code.
1373      *
1374      * @return string the HTML code to go at the start of the <body> tag.
1375      */
1376     public function get_top_of_body_code() {
1377         // First the skip links.
1378         $links = '';
1379         $attributes = array('class'=>'skip');
1380         foreach ($this->skiplinks as $url => $text) {
1381             $attributes['href'] = '#' . $url;
1382             $links .= html_writer::tag('a', $text, $attributes);
1383         }
1384         $output = html_writer::tag('div', $links, array('class'=>'skiplinks')) . "\n";
1385
1386         // Then the clever trick for hiding of things not needed when JS works.
1387         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1388         $this->topofbodydone = true;
1389         return $output;
1390     }
1391
1392     /**
1393      * Generate any HTML that needs to go at the end of the page.
1394      *
1395      * Normally, this method is called automatically by the code that prints the
1396      * page footer. You should not normally need to call it in your own code.
1397      *
1398      * @return string the HTML code to to at the end of the page.
1399      */
1400     public function get_end_code() {
1401         global $CFG;
1402
1403         // Add other requested modules.
1404         $output = $this->get_extra_modules_code();
1405
1406         // All the other linked scripts - there should be as few as possible.
1407         if ($this->jsincludes['footer']) {
1408             foreach ($this->jsincludes['footer'] as $url) {
1409                 $output .= html_writer::script('', $url);
1410             }
1411         }
1412
1413         // Add all needed strings.
1414         if (!empty($this->stringsforjs)) {
1415             $strings = array();
1416             foreach ($this->stringsforjs as $component=>$v) {
1417                 foreach($v as $indentifier => $langstring) {
1418                     $strings[$component][$indentifier] = $langstring->out();
1419                 }
1420             }
1421             $output .= html_writer::script(js_writer::set_variable('M.str', $strings));
1422         }
1423
1424         // Add variables.
1425         if ($this->jsinitvariables['footer']) {
1426             $js = '';
1427             foreach ($this->jsinitvariables['footer'] as $data) {
1428                 list($var, $value) = $data;
1429                 $js .= js_writer::set_variable($var, $value, true);
1430             }
1431             $output .= html_writer::script($js);
1432         }
1433
1434         $inyuijs = $this->get_javascript_code(false);
1435         $ondomreadyjs = $this->get_javascript_code(true);
1436         $jsinit = $this->get_javascript_init_code();
1437         $handlersjs = $this->get_event_handler_code();
1438
1439         // There is no global Y, make sure it is available in your scope.
1440         $js = "YUI().use('node', function(Y) {\n{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}\n});";
1441
1442         $output .= html_writer::script($js);
1443
1444         return $output;
1445     }
1446
1447     /**
1448      * Have we already output the code in the <head> tag?
1449      *
1450      * @return bool
1451      */
1452     public function is_head_done() {
1453         return $this->headdone;
1454     }
1455
1456     /**
1457      * Have we already output the code at the start of the <body> tag?
1458      *
1459      * @return bool
1460      */
1461     public function is_top_of_body_done() {
1462         return $this->topofbodydone;
1463     }
1464 }
1465
1466 /**
1467  * This class represents the YUI configuration.
1468  *
1469  * @copyright 2013 Andrew Nicols
1470  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1471  * @since Moodle 2.5
1472  * @package core
1473  * @category output
1474  */
1475 class YUI_config {
1476     /**
1477      * These settings must be public so that when the object is converted to json they are exposed.
1478      * Note: Some of these are camelCase because YUI uses camelCase variable names.
1479      *
1480      * The settings are described and documented in the YUI API at:
1481      * - http://yuilibrary.com/yui/docs/api/classes/config.html
1482      * - http://yuilibrary.com/yui/docs/api/classes/Loader.html
1483      */
1484     public $debug = false;
1485     public $base;
1486     public $comboBase;
1487     public $combine;
1488     public $filter = null;
1489     public $insertBefore = 'firstthemesheet';
1490     public $groups = array();
1491     public $modules = array();
1492
1493     /**
1494      * @var array List of functions used by the YUI Loader group pattern recognition.
1495      */
1496     protected $jsconfigfunctions = array();
1497
1498     /**
1499      * Create a new group within the YUI_config system.
1500      *
1501      * @param String $name The name of the group. This must be unique and
1502      * not previously used.
1503      * @param Array $config The configuration for this group.
1504      * @return void
1505      */
1506     public function add_group($name, $config) {
1507         if (isset($this->groups[$name])) {
1508             throw new coding_exception("A YUI configuration group for '{$name}' already exists. To make changes to this group use YUI_config->update_group().");
1509         }
1510         $this->groups[$name] = $config;
1511     }
1512
1513     /**
1514      * Update an existing group configuration
1515      *
1516      * Note, any existing configuration for that group will be wiped out.
1517      * This includes module configuration.
1518      *
1519      * @param String $name The name of the group. This must be unique and
1520      * not previously used.
1521      * @param Array $config The configuration for this group.
1522      * @return void
1523      */
1524     public function update_group($name, $config) {
1525         if (!isset($this->groups[$name])) {
1526             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.');
1527         }
1528         $this->groups[$name] = $config;
1529     }
1530
1531     /**
1532      * Set the value of a configuration function used by the YUI Loader's pattern testing.
1533      *
1534      * Only the body of the function should be passed, and not the whole function wrapper.
1535      *
1536      * The JS function your write will be passed a single argument 'name' containing the
1537      * name of the module being loaded.
1538      *
1539      * @param $function String the body of the JavaScript function. This should be used i
1540      * @return String the name of the function to use in the group pattern configuration.
1541      */
1542     public function set_config_function($function) {
1543         $configname = 'yui' . (count($this->jsconfigfunctions) + 1) . 'ConfigFn';
1544         if (isset($this->jsconfigfunctions[$configname])) {
1545             throw new coding_exception("A YUI config function with this name already exists. Config function names must be unique.");
1546         }
1547         $this->jsconfigfunctions[$configname] = $function;
1548         return '@' . $configname . '@';
1549     }
1550
1551     /**
1552      * Allow setting of the config function described in {@see set_config_function} from a file.
1553      * The contents of this file are then passed to set_config_function.
1554      *
1555      * When jsrev is positive, the function is minified and stored in a MUC cache for subsequent uses.
1556      *
1557      * @param $file The path to the JavaScript function used for YUI configuration.
1558      * @return String the name of the function to use in the group pattern configuration.
1559      */
1560     public function set_config_source($file) {
1561         global $CFG;
1562         $cache = cache::make('core', 'yuimodules');
1563
1564         // Attempt to get the metadata from the cache.
1565         $keyname = 'configfn_' . $file;
1566         $fullpath = $CFG->dirroot . '/' . $file;
1567         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1568             $cache->delete($keyname);
1569             $configfn = file_get_contents($fullpath);
1570         } else {
1571             $configfn = $cache->get($keyname);
1572             if ($configfn === false) {
1573                 require_once($CFG->libdir . '/jslib.php');
1574                 $configfn = js_minify($fullpath);
1575                 $cache->set($keyname, $configfn);
1576             }
1577         }
1578         return $this->set_config_function($configfn);
1579     }
1580
1581     /**
1582      * Retrieve the list of JavaScript functions for YUI_config groups.
1583      *
1584      * @return String The complete set of config functions
1585      */
1586     public function get_config_functions() {
1587         $configfunctions = '';
1588         foreach ($this->jsconfigfunctions as $functionname => $function) {
1589             $configfunctions .= "var {$functionname} = function(me) {";
1590             $configfunctions .= $function;
1591             $configfunctions .= "};\n";
1592         }
1593         return $configfunctions;
1594     }
1595
1596     /**
1597      * Update the header JavaScript with any required modification for the YUI Loader.
1598      *
1599      * @param $js String The JavaScript to manipulate.
1600      * @return String the modified JS string.
1601      */
1602     public function update_header_js($js) {
1603         // Update the names of the the configFn variables.
1604         // The PHP json_encode function cannot handle literal names so we have to wrap
1605         // them in @ and then replace them with literals of the same function name.
1606         foreach ($this->jsconfigfunctions as $functionname => $function) {
1607             $js = str_replace('"@' . $functionname . '@"', $functionname, $js);
1608         }
1609         return $js;
1610     }
1611
1612     /**
1613      * Add configuration for a specific module.
1614      *
1615      * @param String $name The name of the module to add configuration for.
1616      * @param Array $config The configuration for the specified module.
1617      * @param String $group The name of the group to add configuration for.
1618      * If not specified, then this module is added to the global
1619      * configuration.
1620      * @return void
1621      */
1622     public function add_module_config($name, $config, $group = null) {
1623         if ($group) {
1624             if (!isset($this->groups[$name])) {
1625                 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.');
1626             }
1627             if (!isset($this->groups[$group]['modules'])) {
1628                 $this->groups[$group]['modules'] = array();
1629             }
1630             $modules = &$this->groups[$group]['modules'];
1631         } else {
1632             $modules = &$this->modules;
1633         }
1634         $modules[$name] = $config;
1635     }
1636
1637     /**
1638      * Add the moodle YUI module metadata for the moodle group to the YUI_config instance.
1639      *
1640      * If js caching is disabled, metadata will not be served causing YUI to calculate
1641      * module dependencies as each module is loaded.
1642      *
1643      * If metadata does not exist it will be created and stored in a MUC entry.
1644      *
1645      * @return void
1646      */
1647     public function add_moodle_metadata() {
1648         global $CFG;
1649         if (!isset($this->groups['moodle'])) {
1650             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.');
1651         }
1652
1653         if (!isset($this->groups['moodle']['modules'])) {
1654             $this->groups['moodle']['modules'] = array();
1655         }
1656
1657         $cache = cache::make('core', 'yuimodules');
1658         if (!isset($CFG->jsrev) || $CFG->jsrev == -1) {
1659             $metadata = array();
1660             $cache->delete('metadata');
1661         } else {
1662             // Attempt to get the metadata from the cache.
1663             if (!$metadata = $cache->get('metadata')) {
1664                 $metadata = $this->get_moodle_metadata();
1665                 $cache->set('metadata', $metadata);
1666             }
1667         }
1668
1669         // Merge with any metadata added specific to this page which was added manually.
1670         $this->groups['moodle']['modules'] = array_merge($this->groups['moodle']['modules'],
1671                 $metadata);
1672     }
1673
1674     /**
1675      * Determine the module metadata for all moodle YUI modules.
1676      *
1677      * This works through all modules capable of serving YUI modules, and attempts to get
1678      * metadata for each of those modules.
1679      *
1680      * @return Array of module metadata
1681      */
1682     private function get_moodle_metadata() {
1683         $moodlemodules = array();
1684         // Core isn't a plugin type or subsystem - handle it seperately.
1685         if ($module = $this->get_moodle_path_metadata(core_component::get_component_directory('core'))) {
1686             $moodlemodules = array_merge($moodlemodules, $module);
1687         }
1688
1689         // Handle other core subsystems.
1690         $subsystems = core_component::get_core_subsystems();
1691         foreach ($subsystems as $subsystem => $path) {
1692             if (is_null($path)) {
1693                 continue;
1694             }
1695             if ($module = $this->get_moodle_path_metadata($path)) {
1696                 $moodlemodules = array_merge($moodlemodules, $module);
1697             }
1698         }
1699
1700         // And finally the plugins.
1701         $plugintypes = core_component::get_plugin_types();
1702         foreach ($plugintypes as $plugintype => $pathroot) {
1703             $pluginlist = core_component::get_plugin_list($plugintype);
1704             foreach ($pluginlist as $plugin => $path) {
1705                 if ($module = $this->get_moodle_path_metadata($path)) {
1706                     $moodlemodules = array_merge($moodlemodules, $module);
1707                 }
1708             }
1709         }
1710
1711         return $moodlemodules;
1712     }
1713
1714     /**
1715      * Helper function process and return the YUI metadata for all of the modules under the specified path.
1716      *
1717      * @param String $path the UNC path to the YUI src directory.
1718      * @return Array the complete array for frankenstyle directory.
1719      */
1720     private function get_moodle_path_metadata($path) {
1721         // Add module metadata is stored in frankenstyle_modname/yui/src/yui_modname/meta/yui_modname.json.
1722         $baseyui = $path . '/yui/src';
1723         $modules = array();
1724         if (is_dir($baseyui)) {
1725             $items = new DirectoryIterator($baseyui);
1726             foreach ($items as $item) {
1727                 if ($item->isDot() or !$item->isDir()) {
1728                     continue;
1729                 }
1730                 $metafile = realpath($baseyui . '/' . $item . '/meta/' . $item . '.json');
1731                 if (!is_readable($metafile)) {
1732                     continue;
1733                 }
1734                 $metadata = file_get_contents($metafile);
1735                 $modules = array_merge($modules, (array) json_decode($metadata));
1736             }
1737         }
1738         return $modules;
1739     }
1740 }
1741
1742 /**
1743  * Invalidate all server and client side JS caches.
1744  */
1745 function js_reset_all_caches() {
1746     global $CFG;
1747
1748     $next = time();
1749     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
1750         // This resolves problems when reset is requested repeatedly within 1s,
1751         // the < 1h condition prevents accidental switching to future dates
1752         // because we might not recover from it.
1753         $next = $CFG->jsrev+1;
1754     }
1755
1756     set_config('jsrev', $next);
1757 }