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 JS variables to be initialised
  68      */
  69     protected $jsinitvariables = array('head'=>array(), 'footer'=>array());
  70
  71     /**
  72      * @var array Included JS scripts
  73      */
  74     protected $jsincludes = array('head'=>array(), 'footer'=>array());
  75
  76     /**
  77      * @var array List of needed function calls
  78      */
  79     protected $jscalls = array('normal'=>array(), 'ondomready'=>array());
  80
  81     /**
  82      * @var array List of skip links, those are needed for accessibility reasons
  83      */
  84     protected $skiplinks = array();
  85
  86     /**
  87      * @var array Javascript code used for initialisation of page, it should
  88      * be relatively small
  89      */
  90     protected $jsinitcode = array();
  91
  92     /**
  93      * @var array of moodle_url Theme sheets, initialised only from core_renderer
  94      */
  95     protected $cssthemeurls = array();
  96
  97     /**
  98      * @var array of moodle_url List of custom theme sheets, these are strongly discouraged!
  99      * Useful mostly only for CSS submitted by teachers that is not part of the theme.
 100      */
 101     protected $cssurls = array();
 102
 103     /**
 104      * @var array List of requested event handlers
 105      */
 106     protected $eventhandlers = array();
 107
 108     /**
 109      * @var array Extra modules
 110      */
 111     protected $extramodules = array();
 112
 113     /**
 114      * @var bool Flag indicated head stuff already printed
 115      */
 116     protected $headdone = false;
 117
 118     /**
 119      * @var bool Flag indicating top of body already printed
 120      */
 121     protected $topofbodydone = false;
 122
 123     /**
 124      * @var YAHOO_util_Loader YUI PHPLoader instance responsible for YUI2 loading
 125      * from PHP only
 126      */
 127     protected $yui2loader;
 128
 129     /**
 130      * @var stdClass YUI PHPLoader instance responsible for YUI3 loading from PHP only
 131      */
 132     protected $yui3loader;
 133
 134     /**
 135      * @var stdClass YUI loader information for YUI3 loading from javascript
 136      */
 137     protected $M_yui_loader;
 138
 139     /**
 140      * @var array Some config vars exposed in JS, please no secret stuff there
 141      */
 142     protected $M_cfg;
 143
 144     /**
 145      * @var array Stores debug backtraces from when JS modules were included in the page
 146      */
 147     protected $debug_moduleloadstacktraces = array();
 148
 149     /**
 150      * Page requirements constructor.
 151      */
 152     public function __construct() {
 153         global $CFG;
 154
 155         // You may need to set up URL rewrite rule because oversized URLs might not be allowed by web server.
 156         $sep = empty($CFG->yuislasharguments) ? '?' : '/';
 157
 158         require_once("$CFG->libdir/yui/phploader/phploader/loader.php");
 159
 160         $this->yui3loader = new stdClass();
 161         $this->yui2loader = new YAHOO_util_Loader($CFG->yui2version);
 162
 163         // set up some loader options
 164         if (debugging('', DEBUG_DEVELOPER)) {
 165             $this->yui3loader->filter = YUI_RAW; // for more detailed logging info use YUI_DEBUG here
 166             $this->yui2loader->filter = YUI_RAW; // for more detailed logging info use YUI_DEBUG here
 167             $this->yui2loader->allowRollups = false;
 168         } else {
 169             $this->yui3loader->filter = null;
 170             $this->yui2loader->filter = null;
 171         }
 172         if (!empty($CFG->useexternalyui) and strpos($CFG->httpswwwroot, 'https:') !== 0) {
 173             $this->yui3loader->base = 'http://yui.yahooapis.com/' . $CFG->yui3version . '/build/';
 174             $this->yui2loader->base = 'http://yui.yahooapis.com/' . $CFG->yui2version . '/build/';
 175             $this->yui3loader->comboBase = 'http://yui.yahooapis.com/combo?';
 176             $this->yui2loader->comboBase = 'http://yui.yahooapis.com/combo?';
 177         } else {
 178             $this->yui3loader->base = $CFG->httpswwwroot . '/lib/yui/'. $CFG->yui3version . '/build/';
 179             $this->yui2loader->base = $CFG->httpswwwroot . '/lib/yui/'. $CFG->yui2version . '/build/';
 180             $this->yui3loader->comboBase = $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep;
 181             $this->yui2loader->comboBase = $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep;
 182         }
 183
 184         // enable combo loader? this significantly helps with caching and performance!
 185         $this->yui3loader->combine = !empty($CFG->yuicomboloading);
 186         $this->yui2loader->combine = !empty($CFG->yuicomboloading);
 187
 188         if (empty($CFG->cachejs)) {
 189             $jsrev = -1;
 190         } else if (empty($CFG->jsrev)) {
 191             $jsrev = 1;
 192         } else {
 193             $jsrev = $CFG->jsrev;
 194         }
 195
 196         // set up JS YUI loader helper object
 197         $this->M_yui_loader = new stdClass();
 198         $this->M_yui_loader->base         = $this->yui3loader->base;
 199         $this->M_yui_loader->comboBase    = $this->yui3loader->comboBase;
 200         $this->M_yui_loader->combine      = $this->yui3loader->combine;
 201         $this->M_yui_loader->filter       = (string)$this->yui3loader->filter;
 202         $this->M_yui_loader->insertBefore = 'firstthemesheet';
 203         $this->M_yui_loader->modules      = array();
 204         $this->M_yui_loader->groups       = array(
 205             'moodle' => array(
 206                 'name' => 'moodle',
 207                 'base' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep.'moodle/'.$jsrev.'/',
 208                 'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep,
 209                 'combine' => $this->yui3loader->combine,
 210                 'filter' => '',
 211                 'ext' => false,
 212                 'root' => 'moodle/'.$jsrev.'/', // Add the rev to the root path so that we can control caching
 213                 'patterns' => array(
 214                     'moodle-' => array(
 215                         'group' => 'moodle',
 216                         'configFn' => '@MOODLECONFIGFN@'
 217                     ),
 218                     'root' => 'moodle'
 219                 )
 220             ),
 221             'local' => array(
 222                 'name' => 'gallery',
 223                 'base' => $CFG->wwwroot.'/lib/yui/gallery/',
 224                 'comboBase' => $CFG->httpswwwroot . '/theme/yui_combo.php'.$sep,
 225                 'combine' => $this->yui3loader->combine,
 226                 'filter' => $this->M_yui_loader->filter,
 227                 'ext' => false,
 228                 'root' => 'gallery/',
 229                 'patterns' => array(
 230                     'gallery-' => array(
 231                         'group' => 'gallery',
 232                         'configFn' => '@GALLERYCONFIGFN@',
 233                     ),
 234                     'root' => 'gallery'
 235                 )
 236             )
 237         );
 238         $this->add_yui2_modules(); // adds loading info for all YUI2 modules
 239         $this->js_module($this->find_module('core_filepicker'));
 240         $this->js_module($this->find_module('core_dock'));
 241
 242     }
 243
 244     /**
 245      * This method adds yui2 modules into the yui3 JS loader so that they can
 246      * be easily included for use in JavaScript.
 247      */
 248     protected function add_yui2_modules() {
 249         //note: this function is definitely not perfect, because
 250         //      it adds tons of markup into each page, but it can be
 251         //      abstracted into separate JS file with proper headers
 252         global $CFG;
 253
 254         $GLOBALS['yui_current'] = array();
 255         require($CFG->libdir.'/yui/phploader/lib/meta/config_'.$CFG->yui2version.'.php');
 256         $info = $GLOBALS['yui_current'];
 257         unset($GLOBALS['yui_current']);
 258
 259         if (empty($CFG->yuicomboloading)) {
 260             $urlbase = $this->yui2loader->base;
 261         } else {
 262             $urlbase = $this->yui2loader->comboBase.$CFG->yui2version.'/build/';
 263         }
 264
 265         $modules = array();
 266         $ignored = array(); // list of CSS modules that are not needed
 267         foreach ($info['moduleInfo'] as $name => $module) {
 268             if ($module['type'] === 'css') {
 269                 $ignored[$name] = true;
 270             } else {
 271                 $modules['yui2-'.$name] = $module;
 272             }
 273         }
 274         foreach ($modules as $name=>$module) {
 275             $module['fullpath'] = $urlbase.$module['path']; // fix path to point to correct location
 276             $module['async'] = false;
 277             unset($module['path']);
 278             unset($module['skinnable']); // we load all YUI2 css automatically, this prevents weird missing css loader problems
 279             foreach(array('requires', 'optional', 'supersedes') as $fixme) {
 280                 if (!empty($module[$fixme])) {
 281                     $fixed = false;
 282                     foreach ($module[$fixme] as $key=>$dep) {
 283                         if (isset($ignored[$dep])) {
 284                             unset($module[$fixme][$key]);
 285                             $fixed = true;
 286                         } else {
 287                             $module[$fixme][$key] = 'yui2-'.$dep;
 288                         }
 289                     }
 290                     if ($fixed) {
 291                         $module[$fixme] = array_merge($module[$fixme]); // fix keys
 292                     }
 293                 }
 294             }
 295             $this->M_yui_loader->modules[$name] = $module;
 296             if (debugging('', DEBUG_DEVELOPER)) {
 297                 if (!array_key_exists($name, $this->debug_moduleloadstacktraces)) {
 298                     $this->debug_moduleloadstacktraces[$name] = array();
 299                 }
 300                 $this->debug_moduleloadstacktraces[$name][] = format_backtrace(debug_backtrace());
 301             }
 302         }
 303     }
 304
 305     /**
 306      * Initialise with the bits of JavaScript that every Moodle page should have.
 307      *
 308      * @param moodle_page $page
 309      * @param core_renderer $renderer
 310      */
 311     protected function init_requirements_data(moodle_page $page, core_renderer $renderer) {
 312         global $CFG;
 313
 314         // JavaScript should always work with $CFG->httpswwwroot rather than $CFG->wwwroot.
 315         // Otherwise, in some situations, users will get warnings about insecure content
 316         // on secure pages from their web browser.
 317
 318         $this->M_cfg = array(
 319             'wwwroot'             => $CFG->httpswwwroot, // Yes, really. See above.
 320             'sesskey'             => sesskey(),
 321             'loadingicon'         => $renderer->pix_url('i/loading_small', 'moodle')->out(false),
 322             'themerev'            => theme_get_revision(),
 323             'slasharguments'      => (int)(!empty($CFG->slasharguments)),
 324             'theme'               => $page->theme->name,
 325             'jsrev'               => ((empty($CFG->cachejs) or empty($CFG->jsrev)) ? -1 : $CFG->jsrev),
 326         );
 327         if (debugging('', DEBUG_DEVELOPER)) {
 328             $this->M_cfg['developerdebug'] = true;
 329         }
 330
 331         // accessibility stuff
 332         $this->skip_link_to('maincontent', get_string('tocontent', 'access'));
 333
 334         // to be removed soon
 335         $this->yui2_lib('dom');        // at least javascript-static.js needs to be migrated to YUI3
 336
 337         $this->string_for_js('confirmation', 'admin');
 338         $this->string_for_js('cancel', 'moodle');
 339         $this->string_for_js('yes', 'moodle');
 340
 341         if ($page->pagelayout === 'frametop') {
 342             $this->js_init_call('M.util.init_frametop');
 343         }
 344     }
 345
 346     /**
 347      * Ensure that the specified JavaScript file is linked to from this page.
 348      *
 349      * NOTE: This function is to be used in rare cases only, please store your JS in module.js file
 350      * and use $PAGE->requires->js_init_call() instead.
 351      *
 352      * By default the link is put at the end of the page, since this gives best page-load performance.
 353      *
 354      * Even if a particular script is requested more than once, it will only be linked
 355      * to once.
 356      *
 357      * @param string|moodle_url $url The path to the .js file, relative to $CFG->dirroot / $CFG->wwwroot.
 358      *      For example '/mod/mymod/customscripts.js'; use moodle_url for external scripts
 359      * @param bool $inhead initialise in head
 360      */
 361     public function js($url, $inhead = false) {
 362         $url = $this->js_fix_url($url);
 363         $where = $inhead ? 'head' : 'footer';
 364         $this->jsincludes[$where][$url->out()] = $url;
 365     }
 366
 367     /**
 368      * Ensure that the specified YUI2 library file, and all its required dependencies,
 369      * are linked to from this page.
 370      *
 371      * By default the link is put at the end of the page, since this gives best page-load
 372      * performance. Optional dependencies are not loaded automatically - if you want
 373      * them you will need to load them first with other calls to this method.
 374      *
 375      * Even if a particular library is requested more than once (perhaps as a dependency
 376      * of other libraries) it will only be linked to once.
 377      *
 378      * The library is leaded as soon as possible, if $OUTPUT->header() not used yet it
 379      * is put into the page header, otherwise it is loaded in the page footer.
 380      *
 381      * @param string|array $libname the name of the YUI2 library you require. For example 'autocomplete'.
 382      */
 383     public function yui2_lib($libname) {
 384         $libnames = (array)$libname;
 385         foreach ($libnames as $lib) {
 386             $this->yui2loader->load($lib);
 387         }
 388     }
 389
 390     /**
 391      * Returns the actual url through which a script is served.
 392      *
 393      * @param moodle_url|string $url full moodle url, or shortened path to script
 394      * @return moodle_url
 395      */
 396     protected function js_fix_url($url) {
 397         global $CFG;
 398
 399         if ($url instanceof moodle_url) {
 400             return $url;
 401         } else if (strpos($url, '/') === 0) {
 402             if (debugging()) {
 403                 // check file existence only when in debug mode
 404                 if (!file_exists($CFG->dirroot . strtok($url, '?'))) {
 405                     throw new coding_exception('Attempt to require a JavaScript file that does not exist.', $url);
 406                 }
 407             }
 408             if (!empty($CFG->cachejs) and !empty($CFG->jsrev) and $CFG->jsrev > 0 and strpos($url, '/lib/editor/') !== 0 and substr($url, -3) === '.js') {
 409                 if (empty($CFG->slasharguments)) {
 410                     return new moodle_url($CFG->httpswwwroot.'/lib/javascript.php', array('rev'=>$CFG->jsrev, 'jsfile'=>$url));
 411                 } else {
 412                     $returnurl = new moodle_url($CFG->httpswwwroot.'/lib/javascript.php');
 413                     $returnurl->set_slashargument('/'.$CFG->jsrev.$url);
 414                     return $returnurl;
 415                 }
 416             } else {
 417                 return new moodle_url($CFG->httpswwwroot.$url);
 418             }
 419         } else {
 420             throw new coding_exception('Invalid JS url, it has to be shortened url starting with / or moodle_url instance.', $url);
 421         }
 422     }
 423
 424     /**
 425      * Find out if JS module present and return details.
 426      *
 427      * @param string $component name of component in frankenstyle, ex: core_group, mod_forum
 428      * @return array description of module or null if not found
 429      */
 430     protected function find_module($component) {
 431         global $CFG, $PAGE;
 432
 433         $module = null;
 434
 435         if (strpos($component, 'core_') === 0) {
 436             // must be some core stuff - list here is not complete, this is just the stuff used from multiple places
 437             // so that we do nto have to repeat the definition of these modules over and over again
 438             switch($component) {
 439                 case 'core_filepicker':
 440                     $module = array('name'     => 'core_filepicker',
 441                                     'fullpath' => '/repository/filepicker.js',
 442                                     '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', 'moodle-core_filepicker'),
 443                                     'strings'  => array(array('lastmodified', 'moodle'), array('name', 'moodle'), array('type', 'repository'), array('size', 'repository'),
 444                                                         array('invalidjson', 'repository'), array('error', 'moodle'), array('info', 'moodle'),
 445                                                         array('nofilesattached', 'repository'), array('filepicker', 'repository'), array('logout', 'repository'),
 446                                                         array('nofilesavailable', 'repository'), array('norepositoriesavailable', 'repository'),
 447                                                         array('fileexistsdialogheader', 'repository'), array('fileexistsdialog_editor', 'repository'),
 448                                                         array('fileexistsdialog_filemanager', 'repository'), array('renameto', 'repository'),
 449                                                         array('referencesexist', 'repository')
 450                                                     ));
 451                     break;
 452                 case 'core_comment':
 453                     $module = array('name'     => 'core_comment',
 454                                     'fullpath' => '/comment/comment.js',
 455                                     'requires' => array('base', 'io-base', 'node', 'json', 'yui2-animation', 'overlay'),
 456                                     'strings' => array(array('confirmdeletecomments', 'admin'), array('yes', 'moodle'), array('no', 'moodle'))
 457                                 );
 458                     break;
 459                 case 'core_role':
 460                     $module = array('name'     => 'core_role',
 461                                     'fullpath' => '/admin/roles/module.js',
 462                                     'requires' => array('node', 'cookie'));
 463                     break;
 464                 case 'core_completion':
 465                     $module = array('name'     => 'core_completion',
 466                                     'fullpath' => '/course/completion.js');
 467                     break;
 468                 case 'core_dock':
 469                     $module = array('name'     => 'core_dock',
 470                                     'fullpath' => '/blocks/dock.js',
 471                                     'requires' => array('base', 'node', 'event-custom', 'event-mouseenter', 'event-resize'),
 472                                     'strings' => array(array('addtodock', 'block'),array('undockitem', 'block'),array('undockall', 'block'),array('thisdirectionvertical', 'langconfig')));
 473                     break;
 474                 case 'core_message':
 475                     $module = array('name'     => 'core_message',
 476                                     'requires' => array('base', 'node', 'event', 'node-event-simulate'),
 477                                     'fullpath' => '/message/module.js');
 478                     break;
 479                 case 'core_group':
 480                     $module = array('name'     => 'core_group',
 481                                     'fullpath' => '/group/module.js',
 482                                     'requires' => array('node', 'overlay', 'event-mouseenter'));
 483                     break;
 484                 case 'core_question_engine':
 485                     $module = array('name'     => 'core_question_engine',
 486                                     'fullpath' => '/question/qengine.js',
 487                                     'requires' => array('node', 'event'));
 488                     break;
 489                 case 'core_rating':
 490                     $module = array('name'     => 'core_rating',
 491                                     'fullpath' => '/rating/module.js',
 492                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json'));
 493                     break;
 494                 case 'core_filetree':
 495                     $module = array('name'     => 'core_filetree',
 496                                     'fullpath' => '/files/module.js',
 497                                     'requires' => array('node', 'event', 'overlay', 'io-base', 'json', 'yui2-treeview'));
 498                     break;
 499                 case 'core_dndupload':
 500                     $module = array('name'     => 'core_dndupload',
 501                                     'fullpath' => '/lib/form/dndupload.js',
 502                                     'requires' => array('node', 'event', 'json', 'core_filepicker'),
 503                                     'strings'  => array(array('uploadformlimit', 'moodle'), array('droptoupload', 'moodle'), array('maxfilesreached', 'moodle'), array('dndenabled_inbox', 'moodle'), array('fileexists', 'moodle')));
 504                     break;
 505             }
 506
 507         } else {
 508             if ($dir = get_component_directory($component)) {
 509                 if (file_exists("$dir/module.js")) {
 510                     if (strpos($dir, $CFG->dirroot.'/') === 0) {
 511                         $dir = substr($dir, strlen($CFG->dirroot));
 512                         $module = array('name'=>$component, 'fullpath'=>"$dir/module.js", 'requires' => array());
 513                     }
 514                 }
 515             }
 516         }
 517
 518         return $module;
 519     }
 520
 521     /**
 522      * Append YUI3 module to default YUI3 JS loader.
 523      * The structure of module array is described at {@link http://developer.yahoo.com/yui/3/yui/}
 524      *
 525      * @param string|array $module name of module (details are autodetected), or full module specification as array
 526      * @return void
 527      */
 528     public function js_module($module) {
 529         global $CFG;
 530
 531         if (empty($module)) {
 532             throw new coding_exception('Missing YUI3 module name or full description.');
 533         }
 534
 535         if (is_string($module)) {
 536             $module = $this->find_module($module);
 537         }
 538
 539         if (empty($module) or empty($module['name']) or empty($module['fullpath'])) {
 540             throw new coding_exception('Missing YUI3 module details.');
 541         }
 542
 543         // Don't load this module if we already have, no need to!
 544         if ($this->js_module_loaded($module['name'])) {
 545             if (debugging('', DEBUG_DEVELOPER)) {
 546                 $this->debug_moduleloadstacktraces[$module['name']][] = format_backtrace(debug_backtrace());
 547             }
 548             return;
 549         }
 550
 551         $module['fullpath'] = $this->js_fix_url($module['fullpath'])->out(false);
 552         // add all needed strings
 553         if (!empty($module['strings'])) {
 554             foreach ($module['strings'] as $string) {
 555                 $identifier = $string[0];
 556                 $component = isset($string[1]) ? $string[1] : 'moodle';
 557                 $a = isset($string[2]) ? $string[2] : null;
 558                 $this->string_for_js($identifier, $component, $a);
 559             }
 560         }
 561         unset($module['strings']);
 562
 563         // Process module requirements and attempt to load each. This allows
 564         // moodle modules to require each other.
 565         if (!empty($module['requires'])){
 566             foreach ($module['requires'] as $requirement) {
 567                 $rmodule = $this->find_module($requirement);
 568                 if (is_array($rmodule)) {
 569                     $this->js_module($rmodule);
 570                 }
 571             }
 572         }
 573
 574         if ($this->headdone) {
 575             $this->extramodules[$module['name']] = $module;
 576         } else {
 577             $this->M_yui_loader->modules[$module['name']] = $module;
 578         }
 579         if (debugging('', DEBUG_DEVELOPER)) {
 580             if (!array_key_exists($module['name'], $this->debug_moduleloadstacktraces)) {
 581                 $this->debug_moduleloadstacktraces[$module['name']] = array();
 582             }
 583             $this->debug_moduleloadstacktraces[$module['name']][] = format_backtrace(debug_backtrace());
 584         }
 585     }
 586
 587     /**
 588      * Returns true if the module has already been loaded.
 589      *
 590      * @param string|array $module
 591      * @return bool True if the module has already been loaded
 592      */
 593     protected function js_module_loaded($module) {
 594         if (is_string($module)) {
 595             $modulename = $module;
 596         } else {
 597             $modulename = $module['name'];
 598         }
 599         return array_key_exists($modulename, $this->M_yui_loader->modules) ||
 600                array_key_exists($modulename, $this->extramodules);
 601     }
 602
 603     /**
 604      * Returns the stacktraces from loading js modules.
 605      * @return array
 606      */
 607     public function get_loaded_modules() {
 608         return $this->debug_moduleloadstacktraces;
 609     }
 610
 611     /**
 612      * Ensure that the specified CSS file is linked to from this page.
 613      *
 614      * Because stylesheet links must go in the <head> part of the HTML, you must call
 615      * this function before {@link get_head_code()} is called. That normally means before
 616      * the call to print_header. If you call it when it is too late, an exception
 617      * will be thrown.
 618      *
 619      * Even if a particular style sheet is requested more than once, it will only
 620      * be linked to once.
 621      *
 622      * Please note use of this feature is strongly discouraged,
 623      * it is suitable only for places where CSS is submitted directly by teachers.
 624      * (Students must not be allowed to submit any external CSS because it may
 625      * contain embedded javascript!). Example of correct use is mod/data.
 626      *
 627      * @param string $stylesheet The path to the .css file, relative to $CFG->wwwroot.
 628      *   For example:
 629      *      $PAGE->requires->css('mod/data/css.php?d='.$data->id);
 630      */
 631     public function css($stylesheet) {
 632         global $CFG;
 633
 634         if ($this->headdone) {
 635             throw new coding_exception('Cannot require a CSS file after &lt;head> has been printed.', $stylesheet);
 636         }
 637
 638         if ($stylesheet instanceof moodle_url) {
 639             // ok
 640         } else if (strpos($stylesheet, '/') === 0) {
 641             $stylesheet = new moodle_url($CFG->httpswwwroot.$stylesheet);
 642         } else {
 643             throw new coding_exception('Invalid stylesheet parameter.', $stylesheet);
 644         }
 645
 646         $this->cssurls[$stylesheet->out()] = $stylesheet; // overrides
 647     }
 648
 649     /**
 650      * Add theme stylkesheet to page - do not use from plugin code,
 651      * this should be called only from the core renderer!
 652      *
 653      * @param moodle_url $stylesheet
 654      * @return void
 655      */
 656     public function css_theme(moodle_url $stylesheet) {
 657         $this->cssthemeurls[] = $stylesheet;
 658     }
 659
 660     /**
 661      * Ensure that a skip link to a given target is printed at the top of the <body>.
 662      *
 663      * You must call this function before {@link get_top_of_body_code()}, (if not, an exception
 664      * will be thrown). That normally means you must call this before the call to print_header.
 665      *
 666      * If you ask for a particular skip link to be printed, it is then your responsibility
 667      * to ensure that the appropriate <a name="..."> tag is printed in the body of the
 668      * page, so that the skip link goes somewhere.
 669      *
 670      * Even if a particular skip link is requested more than once, only one copy of it will be output.
 671      *
 672      * @param $target the name of anchor this link should go to. For example 'maincontent'.
 673      * @param $linktext The text to use for the skip link. Normally get_string('skipto', 'access', ...);
 674      */
 675     public function skip_link_to($target, $linktext) {
 676         if ($this->topofbodydone) {
 677             debugging('Page header already printed, can not add skip links any more, code needs to be fixed.');
 678             return;
 679         }
 680         $this->skiplinks[$target] = $linktext;
 681     }
 682
 683     /**
 684      * !!!DEPRECATED!!! please use js_init_call() if possible
 685      * Ensure that the specified JavaScript function is called from an inline script
 686      * somewhere on this page.
 687      *
 688      * By default the call will be put in a script tag at the
 689      * end of the page after initialising Y instance, since this gives best page-load
 690      * performance and allows you to use YUI3 library.
 691      *
 692      * If you request that a particular function is called several times, then
 693      * that is what will happen (unlike linking to a CSS or JS file, where only
 694      * one link will be output).
 695      *
 696      * The main benefit of the method is the automatic encoding of all function parameters.
 697      *
 698      * @param string $function the name of the JavaScritp function to call. Can
 699      *      be a compound name like 'Y.Event.purgeElement'. Can also be
 700      *      used to create and object by using a 'function name' like 'new user_selector'.
 701      * @param array $arguments and array of arguments to be passed to the function.
 702      *      When generating the function call, this will be escaped using json_encode,
 703      *      so passing objects and arrays should work.
 704      * @param bool $ondomready If tru the function is only called when the dom is
 705      *      ready for manipulation.
 706      * @param int $delay The delay before the function is called.
 707      */
 708     public function js_function_call($function, array $arguments = null, $ondomready = false, $delay = 0) {
 709         $where = $ondomready ? 'ondomready' : 'normal';
 710         $this->jscalls[$where][] = array($function, $arguments, $delay);
 711     }
 712
 713     /**
 714      * Adds a call to make use of a YUI gallery module. DEPRECATED DO NOT USE!!!
 715      *
 716      * @deprecated DO NOT USE
 717      *
 718      * @param string|array $modules One or more gallery modules to require
 719      * @param string $version
 720      * @param string $function
 721      * @param array $arguments
 722      * @param bool $ondomready
 723      */
 724     public function js_gallery_module($modules, $version, $function, array $arguments = null, $ondomready = false) {
 725         global $CFG;
 726         debugging('This function will be removed before 2.0 is released please change it from js_gallery_module to yui_module', DEBUG_DEVELOPER);
 727         $this->yui_module($modules, $function, $arguments, $version, $ondomready);
 728     }
 729
 730     /**
 731      * Creates a JavaScript function call that requires one or more modules to be loaded
 732      *
 733      * This function can be used to include all of the standard YUI module types within JavaScript:
 734      *     - YUI3 modules    [node, event, io]
 735      *     - YUI2 modules    [yui2-*]
 736      *     - Moodle modules  [moodle-*]
 737      *     - Gallery modules [gallery-*]
 738      *
 739      * @param array|string $modules One or more modules
 740      * @param string $function The function to call once modules have been loaded
 741      * @param array $arguments An array of arguments to pass to the function
 742      * @param string $galleryversion The gallery version to use
 743      * @param bool $ondomready
 744      */
 745     public function yui_module($modules, $function, array $arguments = null, $galleryversion = '2010.04.08-12-35', $ondomready = false) {
 746         global $CFG;
 747
 748         if (!is_array($modules)) {
 749             $modules = array($modules);
 750         }
 751         if (empty($CFG->useexternalyui)) {
 752             // We need to set the M.yui.galleryversion to the correct version
 753             $jscode = 'M.yui.galleryversion='.json_encode($galleryversion).';';
 754         } else {
 755             // Set Y's config.gallery to the version
 756             $jscode = 'Y.config.gallery='.json_encode($galleryversion).';';
 757         }
 758         $jscode .= 'Y.use('.join(',', array_map('json_encode', convert_to_array($modules))).',function() {'.js_writer::function_call($function, $arguments).'});';
 759         if ($ondomready) {
 760             $jscode = "Y.on('domready', function() { $jscode });";
 761         }
 762         $this->jsinitcode[] = $jscode;
 763     }
 764
 765     /**
 766      * Ensure that the specified JavaScript function is called from an inline script
 767      * from page footer.
 768      *
 769      * @param string $function the name of the JavaScritp function to with init code,
 770      *      usually something like 'M.mod_mymodule.init'
 771      * @param array $extraarguments and array of arguments to be passed to the function.
 772      *      The first argument is always the YUI3 Y instance with all required dependencies
 773      *      already loaded.
 774      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
 775      * @param array $module JS module specification array
 776      */
 777     public function js_init_call($function, array $extraarguments = null, $ondomready = false, array $module = null) {
 778         $jscode = js_writer::function_call_with_Y($function, $extraarguments);
 779         if (!$module) {
 780             // detect module automatically
 781             if (preg_match('/M\.([a-z0-9]+_[^\.]+)/', $function, $matches)) {
 782                 $module = $this->find_module($matches[1]);
 783             }
 784         }
 785
 786         $this->js_init_code($jscode, $ondomready, $module);
 787     }
 788
 789     /**
 790      * Add short static javascript code fragment to page footer.
 791      * This is intended primarily for loading of js modules and initialising page layout.
 792      * Ideally the JS code fragment should be stored in plugin renderer so that themes
 793      * may override it.
 794      * @param string $jscode
 795      * @param bool $ondomready wait for dom ready (helps with some IE problems when modifying DOM)
 796      * @param array $module JS module specification array
 797      */
 798     public function js_init_code($jscode, $ondomready = false, array $module = null) {
 799         $jscode = trim($jscode, " ;\n"). ';';
 800
 801         if ($module) {
 802             $this->js_module($module);
 803             $modulename = $module['name'];
 804             $jscode = "Y.use('$modulename', function(Y) { $jscode });";
 805         }
 806
 807         if ($ondomready) {
 808             $jscode = "Y.on('domready', function() { $jscode });";
 809         }
 810
 811         $this->jsinitcode[] = $jscode;
 812     }
 813
 814     /**
 815      * Make a language string available to JavaScript.
 816      *
 817      * All the strings will be available in a M.str object in the global namespace.
 818      * So, for example, after a call to $PAGE->requires->string_for_js('course', 'moodle');
 819      * then the JavaScript variable M.str.moodle.course will be 'Course', or the
 820      * equivalent in the current language.
 821      *
 822      * The arguments to this function are just like the arguments to get_string
 823      * except that $component is not optional, and there are some aspects to consider
 824      * when the string contains {$a} placeholder.
 825      *
 826      * If the string does not contain any {$a} placeholder, you can simply use
 827      * M.str.component.identifier to obtain it. If you prefer, you can call
 828      * M.util.get_string(identifier, component) to get the same result.
 829      *
 830      * If you need to use {$a} placeholders, there are two options. Either the
 831      * placeholder should be substituted in PHP on server side or it should
 832      * be substituted in Javascript at client side.
 833      *
 834      * To substitute the placeholder at server side, just provide the required
 835      * value for the placeholder when you require the string. Because each string
 836      * is only stored once in the JavaScript (based on $identifier and $module)
 837      * you cannot get the same string with two different values of $a. If you try,
 838      * an exception will be thrown. Once the placeholder is substituted, you can
 839      * use M.str or M.util.get_string() as shown above:
 840      *
 841      *     // require the string in PHP and replace the placeholder
 842      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle', $USER);
 843      *     // use the result of the substitution in Javascript
 844      *     alert(M.str.moodle.fullnamedisplay);
 845      *
 846      * To substitute the placeholder at client side, use M.util.get_string()
 847      * function. It implements the same logic as {@link get_string()}:
 848      *
 849      *     // require the string in PHP but keep {$a} as it is
 850      *     $PAGE->requires->string_for_js('fullnamedisplay', 'moodle');
 851      *     // provide the values on the fly in Javascript
 852      *     user = { firstname : 'Harry', lastname : 'Potter' }
 853      *     alert(M.util.get_string('fullnamedisplay', 'moodle', user);
 854      *
 855      * If you do need the same string expanded with different $a values in PHP
 856      * on server side, then the solution is to put them in your own data structure
 857      * (e.g. and array) that you pass to JavaScript with {@link data_for_js()}.
 858      *
 859      * @param string $identifier the desired string.
 860      * @param string $component the language file to look in.
 861      * @param mixed $a any extra data to add into the string (optional).
 862      */
 863     public function string_for_js($identifier, $component, $a = NULL) {
 864         $string = get_string($identifier, $component, $a);
 865         if (!$component) {
 866             throw new coding_exception('The $module parameter is required for page_requirements_manager::string_for_js.');
 867         }
 868         if (isset($this->stringsforjs[$component][$identifier]) && $this->stringsforjs[$component][$identifier] !== $string) {
 869             throw new coding_exception("Attempt to re-define already required string '$identifier' " .
 870                     "from lang file '$component'. Did you already ask for it with a different \$a? {$this->stringsforjs[$component][$identifier]} !== $string");
 871         }
 872         $this->stringsforjs[$component][$identifier] = $string;
 873     }
 874
 875     /**
 876      * Make an array of language strings available for JS
 877      *
 878      * This function calls the above function {@link string_for_js()} for each requested
 879      * string in the $identifiers array that is passed to the argument for a single module
 880      * passed in $module.
 881      *
 882      * <code>
 883      * $PAGE->requires->strings_for_js(array('one', 'two', 'three'), 'mymod', array('a', null, 3));
 884      *
 885      * // The above is identitical to calling
 886      *
 887      * $PAGE->requires->string_for_js('one', 'mymod', 'a');
 888      * $PAGE->requires->string_for_js('two', 'mymod');
 889      * $PAGE->requires->string_for_js('three', 'mymod', 3);
 890      * </code>
 891      *
 892      * @param array $identifiers An array of desired strings
 893      * @param string $component The module to load for
 894      * @param mixed $a This can either be a single variable that gets passed as extra
 895      *         information for every string or it can be an array of mixed data where the
 896      *         key for the data matches that of the identifier it is meant for.
 897      *
 898      */
 899     public function strings_for_js($identifiers, $component, $a=NULL) {
 900         foreach ($identifiers as $key => $identifier) {
 901             if (is_array($a) && array_key_exists($key, $a)) {
 902                 $extra = $a[$key];
 903             } else {
 904                 $extra = $a;
 905             }
 906             $this->string_for_js($identifier, $component, $extra);
 907         }
 908     }
 909
 910     /**
 911      * !!!!!!DEPRECATED!!!!!! please use js_init_call() for everything now.
 912      *
 913      * Make some data from PHP available to JavaScript code.
 914      *
 915      * For example, if you call
 916      * <pre>
 917      *      $PAGE->requires->data_for_js('mydata', array('name' => 'Moodle'));
 918      * </pre>
 919      * then in JavsScript mydata.name will be 'Moodle'.
 920      * @param string $variable the the name of the JavaScript variable to assign the data to.
 921      *      Will probably work if you use a compound name like 'mybuttons.button[1]', but this
 922      *      should be considered an experimental feature.
 923      * @param mixed $data The data to pass to JavaScript. This will be escaped using json_encode,
 924      *      so passing objects and arrays should work.
 925      * @param bool $inhead initialise in head
 926      * @return void
 927      */
 928     public function data_for_js($variable, $data, $inhead=false) {
 929         $where = $inhead ? 'head' : 'footer';
 930         $this->jsinitvariables[$where][] = array($variable, $data);
 931     }
 932
 933     /**
 934      * Creates a YUI event handler.
 935      *
 936      * @param mixed $selector standard YUI selector for elemnts, may be array or string, element id is in the form "#idvalue"
 937      * @param string $event A valid DOM event (click, mousedown, change etc.)
 938      * @param string $function The name of the function to call
 939      * @param array  $arguments An optional array of argument parameters to pass to the function
 940      */
 941     public function event_handler($selector, $event, $function, array $arguments = null) {
 942         $this->eventhandlers[] = array('selector'=>$selector, 'event'=>$event, 'function'=>$function, 'arguments'=>$arguments);
 943     }
 944
 945     /**
 946      * Returns code needed for registering of event handlers.
 947      * @return string JS code
 948      */
 949     protected function get_event_handler_code() {
 950         $output = '';
 951         foreach ($this->eventhandlers as $h) {
 952             $output .= js_writer::event_handler($h['selector'], $h['event'], $h['function'], $h['arguments']);
 953         }
 954         return $output;
 955     }
 956
 957     /**
 958      * Get the inline JavaScript code that need to appear in a particular place.
 959      * @param bool $ondomready
 960      * @return string
 961      */
 962     protected function get_javascript_code($ondomready) {
 963         $where = $ondomready ? 'ondomready' : 'normal';
 964         $output = '';
 965         if ($this->jscalls[$where]) {
 966             foreach ($this->jscalls[$where] as $data) {
 967                 $output .= js_writer::function_call($data[0], $data[1], $data[2]);
 968             }
 969             if (!empty($ondomready)) {
 970                 $output = "    Y.on('domready', function() {\n$output\n    });";
 971             }
 972         }
 973         return $output;
 974     }
 975
 976     /**
 977      * Returns js code to be executed when Y is available.
 978      * @return string
 979      */
 980     protected function get_javascript_init_code() {
 981         if (count($this->jsinitcode)) {
 982             return implode("\n", $this->jsinitcode) . "\n";
 983         }
 984         return '';
 985     }
 986
 987     /**
 988      * Returns basic YUI3 JS loading code.
 989      * YUI3 is using autoloading of both CSS and JS code.
 990      *
 991      * Major benefit of this compared to standard js/csss loader is much improved
 992      * caching, better browser cache utilisation, much fewer http requests.
 993      *
 994      * @return string
 995      */
 996     protected function get_yui3lib_headcode() {
 997         global $CFG;
 998
 999         $code = '';
1000
1001         if ($this->yui3loader->combine) {
1002             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->comboBase
1003                      .$CFG->yui3version.'/build/cssreset/reset-min.css&amp;'
1004                      .$CFG->yui3version.'/build/cssfonts/fonts-min.css&amp;'
1005                      .$CFG->yui3version.'/build/cssgrids/grids-min.css&amp;'
1006                      .$CFG->yui3version.'/build/cssbase/base-min.css" />';
1007             $code .= '<script type="text/javascript" src="'.$this->yui3loader->comboBase.$CFG->yui3version.'/build/yui/yui-min.js"></script>';
1008         } else {
1009             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.'cssreset/reset-min.css" />';
1010             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.'cssfonts/fonts-min.css" />';
1011             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.'cssgrids/grids-min.css" />';
1012             $code .= '<link rel="stylesheet" type="text/css" href="'.$this->yui3loader->base.'cssbase/base-min.css" />';
1013             $code .= '<script type="text/javascript" src="'.$this->yui3loader->base.'yui/yui-min.js"></script>';
1014         }
1015
1016
1017         if ($this->yui3loader->filter === YUI_RAW) {
1018             $code = str_replace('-min.css', '.css', $code);
1019             $code = str_replace('-min.js', '.js', $code);
1020         } else if ($this->yui3loader->filter === YUI_DEBUG) {
1021             $code = str_replace('-min.css', '.css', $code);
1022             $code = str_replace('-min.js', '-debug.js', $code);
1023         }
1024
1025         return $code;
1026     }
1027
1028     /**
1029      * Returns basic YUI2 JS loading code.
1030      * It can be called manually at any time.
1031      * If called manually the result needs to be output using echo().
1032      *
1033      * Major benefit of this compared to standard js loader is much improved
1034      * caching, better browser cache utilisation, much fewer http requests.
1035      *
1036      * All YUI2 CSS is loaded automatically.
1037      *
1038      * @return string JS embedding code
1039      */
1040     public function get_yui2lib_code() {
1041         global $CFG;
1042
1043         if ($this->headdone) {
1044             $code = $this->yui2loader->script();
1045         } else {
1046             $code = $this->yui2loader->script();
1047             if ($this->yui2loader->combine) {
1048                 $skinurl = $this->yui2loader->comboBase . $CFG->yui2version . '/build/assets/skins/sam/skin.css';
1049             } else {
1050                 $skinurl = $this->yui2loader->base . 'assets/skins/sam/skin.css';
1051             }
1052             // please note this is a temporary hack until we fully migrate to later YUI3 that has all the widgets
1053             $attributes = array('rel'=>'stylesheet', 'type'=>'text/css', 'href'=>$skinurl);
1054             $code .= "\n" . html_writer::empty_tag('link', $attributes) . "\n";
1055         }
1056         $code = str_replace('&amp;', '&', $code);
1057         $code = str_replace('&', '&amp;', $code);
1058         return $code;
1059     }
1060
1061     /**
1062      * Returns html tags needed for inclusion of theme CSS
1063      *
1064      * @return string
1065      */
1066     protected function get_css_code() {
1067         // First of all the theme CSS, then any custom CSS
1068         // Please note custom CSS is strongly discouraged,
1069         // because it can not be overridden by themes!
1070         // It is suitable only for things like mod/data which accepts CSS from teachers.
1071         $attributes = array('rel'=>'stylesheet', 'type'=>'text/css');
1072
1073         // This line of code may look funny but it is currently required in order
1074         // to avoid MASSIVE display issues in Internet Explorer.
1075         // As of IE8 + YUI3.1.1 the reference stylesheet (firstthemesheet) gets
1076         // ignored whenever another resource is added until such time as a redraw
1077         // is forced, usually by moving the mouse over the affected element.
1078         $code = html_writer::tag('script', '/** Required in order to fix style inclusion problems in IE with YUI **/', array('id'=>'firstthemesheet', 'type'=>'text/css'));
1079
1080         $urls = $this->cssthemeurls + $this->cssurls;
1081         foreach ($urls as $url) {
1082             $attributes['href'] = $url;
1083             $code .= html_writer::empty_tag('link', $attributes) . "\n";
1084             // this id is needed in first sheet only so that theme may override YUI sheets laoded on the fly
1085             unset($attributes['id']);
1086         }
1087
1088         return $code;
1089     }
1090
1091     /**
1092      * Adds extra modules specified after printing of page header
1093      *
1094      * @return string
1095      */
1096     protected function get_extra_modules_code() {
1097         if (empty($this->extramodules)) {
1098             return '';
1099         }
1100         return html_writer::script(js_writer::function_call('M.yui.add_module', array($this->extramodules)));
1101     }
1102
1103     /**
1104      * Generate any HTML that needs to go inside the <head> tag.
1105      *
1106      * Normally, this method is called automatically by the code that prints the
1107      * <head> tag. You should not normally need to call it in your own code.
1108      *
1109      * @param moodle_page $page
1110      * @param core_renderer $renderer
1111      * @return string the HTML code to to inside the <head> tag.
1112      */
1113     public function get_head_code(moodle_page $page, core_renderer $renderer) {
1114         global $CFG;
1115
1116         // note: the $page and $output are not stored here because it would
1117         // create circular references in memory which prevents garbage collection
1118         $this->init_requirements_data($page, $renderer);
1119
1120         // yui3 JS and CSS is always loaded first - it is cached in browser
1121         $output = $this->get_yui3lib_headcode();
1122
1123         // BC: load basic YUI2 for now, all yui2 things should be loaded via Y.use('yui2-oldmodulename')
1124         $output .= $this->get_yui2lib_code();
1125
1126         // now theme CSS + custom CSS in this specific order
1127         $output .= $this->get_css_code();
1128
1129         // set up global YUI3 loader object - this should contain all code needed by plugins
1130         // note: in JavaScript just use "YUI(M.yui.loader).use('overlay', function(Y) { .... });"
1131         // this needs to be done before including any other script
1132         $js = "var M = {}; M.yui = {}; var moodleConfigFn = function(me) {var p = me.path, b = me.name.replace(/^moodle-/,'').split('-', 3), n = b.pop();if (/(skin|core)/.test(n)) {n = b.pop();me.type = 'css';};me.path = b.join('-')+'/'+n+'/'+n+'.'+me.type;}; var galleryConfigFn = function(me) {var p = me.path,v=M.yui.galleryversion,f;if(/-(skin|core)/.test(me.name)) {me.type = 'css';p = p.replace(/-(skin|core)/, '').replace(/\.js/, '.css').split('/'), f = p.pop().replace(/(\-(min|debug))/, '');if (/-skin/.test(me.name)) {p.splice(p.length,0,v,'assets','skins','sam', f);} else {p.splice(p.length,0,v,'assets', f);};} else {p = p.split('/'), f = p.pop();p.splice(p.length,0,v, f);};me.path = p.join('/');};\n";
1133         $js .= js_writer::set_variable('M.yui.loader', $this->M_yui_loader, false) . "\n";
1134         $js .= js_writer::set_variable('M.cfg', $this->M_cfg, false);
1135         $js = str_replace('"@GALLERYCONFIGFN@"', 'galleryConfigFn', $js);
1136         $js = str_replace('"@MOODLECONFIGFN@"', 'moodleConfigFn', $js);
1137
1138         $output .= html_writer::script($js);
1139
1140         // link our main JS file, all core stuff should be there
1141         $output .= html_writer::script('', $this->js_fix_url('/lib/javascript-static.js'));
1142
1143         // add variables
1144         if ($this->jsinitvariables['head']) {
1145             $js = '';
1146             foreach ($this->jsinitvariables['head'] as $data) {
1147                 list($var, $value) = $data;
1148                 $js .= js_writer::set_variable($var, $value, true);
1149             }
1150             $output .= html_writer::script($js);
1151         }
1152
1153         // all the other linked things from HEAD - there should be as few as possible
1154         if ($this->jsincludes['head']) {
1155             foreach ($this->jsincludes['head'] as $url) {
1156                 $output .= html_writer::script('', $url);
1157             }
1158         }
1159
1160         // mark head sending done, it is not possible to anything there
1161         $this->headdone = true;
1162
1163         return $output;
1164     }
1165
1166     /**
1167      * Generate any HTML that needs to go at the start of the <body> tag.
1168      *
1169      * Normally, this method is called automatically by the code that prints the
1170      * <head> tag. You should not normally need to call it in your own code.
1171      *
1172      * @return string the HTML code to go at the start of the <body> tag.
1173      */
1174     public function get_top_of_body_code() {
1175         // first the skip links
1176         $links = '';
1177         $attributes = array('class'=>'skip');
1178         foreach ($this->skiplinks as $url => $text) {
1179             $attributes['href'] = '#' . $url;
1180             $links .= html_writer::tag('a', $text, $attributes);
1181         }
1182         $output = html_writer::tag('div', $links, array('class'=>'skiplinks')) . "\n";
1183
1184         // then the clever trick for hiding of things not needed when JS works
1185         $output .= html_writer::script("document.body.className += ' jsenabled';") . "\n";
1186         $this->topofbodydone = true;
1187         return $output;
1188     }
1189
1190     /**
1191      * Generate any HTML that needs to go at the end of the page.
1192      *
1193      * Normally, this method is called automatically by the code that prints the
1194      * page footer. You should not normally need to call it in your own code.
1195      *
1196      * @return string the HTML code to to at the end of the page.
1197      */
1198     public function get_end_code() {
1199         global $CFG;
1200         // add other requested modules
1201         $output = $this->get_extra_modules_code();
1202
1203         // add missing YUI2 YUI - to be removed once we convert everything to YUI3!
1204         $output .= $this->get_yui2lib_code();
1205
1206         // all the other linked scripts - there should be as few as possible
1207         if ($this->jsincludes['footer']) {
1208             foreach ($this->jsincludes['footer'] as $url) {
1209                 $output .= html_writer::script('', $url);
1210             }
1211         }
1212
1213         // add all needed strings
1214         if (!empty($this->stringsforjs)) {
1215             $output .= html_writer::script(js_writer::set_variable('M.str', $this->stringsforjs));
1216         }
1217
1218         // add variables
1219         if ($this->jsinitvariables['footer']) {
1220             $js = '';
1221             foreach ($this->jsinitvariables['footer'] as $data) {
1222                 list($var, $value) = $data;
1223                 $js .= js_writer::set_variable($var, $value, true);
1224             }
1225             $output .= html_writer::script($js);
1226         }
1227
1228         $inyuijs = $this->get_javascript_code(false);
1229         $ondomreadyjs = $this->get_javascript_code(true);
1230         $jsinit = $this->get_javascript_init_code();
1231         $handlersjs = $this->get_event_handler_code();
1232
1233         // there is no global Y, make sure it is available in your scope
1234         $js = "YUI(M.yui.loader).use('node', function(Y) {\n{$inyuijs}{$ondomreadyjs}{$jsinit}{$handlersjs}\n});";
1235
1236         $output .= html_writer::script($js);
1237
1238         return $output;
1239     }
1240
1241     /**
1242      * Have we already output the code in the <head> tag?
1243      *
1244      * @return bool
1245      */
1246     public function is_head_done() {
1247         return $this->headdone;
1248     }
1249
1250     /**
1251      * Have we already output the code at the start of the <body> tag?
1252      *
1253      * @return bool
1254      */
1255     public function is_top_of_body_done() {
1256         return $this->topofbodydone;
1257     }
1258 }
1259
1260 /**
1261  * Invalidate all server and client side JS caches.
1262  */
1263 function js_reset_all_caches() {
1264     global $CFG;
1265     require_once("$CFG->libdir/filelib.php");
1266
1267     $next = time();
1268     if (isset($CFG->jsrev) and $next <= $CFG->jsrev and $CFG->jsrev - $next < 60*60) {
1269         // This resolves problems when reset is requested repeatedly within 1s,
1270         // the < 1h condition prevents accidental switching to future dates
1271         // because we might not recover from it.
1272         $next = $CFG->jsrev+1;
1273     }
1274
1275     set_config('jsrev', $next);
1276     fulldelete("$CFG->cachedir/js");
1277 }