resources/mediawiki/mediawiki.js

   1 /*
   2  * Core MediaWiki JavaScript Library
   3  */
   4
   5 var mw = ( function ( $, undefined ) {
   6         'use strict';
   7
   8         /* Private Members */
   9
  10         var hasOwn = Object.prototype.hasOwnProperty,
  11                 slice = Array.prototype.slice;
  12
  13         /* Object constructors */
  14
  15         /**
  16          * Map
  17          *
  18          * Creates an object that can be read from or written to from prototype functions
  19          * that allow both single and multiple variables at once.
  20          *
  21          * @param global boolean Whether to store the values in the global window
  22          *  object or a exclusively in the object property 'values'.
  23          * @return Map
  24          */
  25         function Map( global ) {
  26                 this.values = global === true ? window : {};
  27                 return this;
  28         }
  29
  30         Map.prototype = {
  31                 /**
  32                  * Get the value of one or multiple a keys.
  33                  *
  34                  * If called with no arguments, all values will be returned.
  35                  *
  36                  * @param selection mixed String key or array of keys to get values for.
  37                  * @param fallback mixed Value to use in case key(s) do not exist (optional).
  38                  * @return mixed If selection was a string returns the value or null,
  39                  *  If selection was an array, returns an object of key/values (value is null if not found),
  40                  *  If selection was not passed or invalid, will return the 'values' object member (be careful as
  41                  *  objects are always passed by reference in JavaScript!).
  42                  * @return Values as a string or object, null if invalid/inexistant.
  43                  */
  44                 get: function ( selection, fallback ) {
  45                         var results, i;
  46
  47                         if ( $.isArray( selection ) ) {
  48                                 selection = slice.call( selection );
  49                                 results = {};
  50                                 for ( i = 0; i < selection.length; i += 1 ) {
  51                                         results[selection[i]] = this.get( selection[i], fallback );
  52                                 }
  53                                 return results;
  54                         }
  55
  56                         if ( typeof selection === 'string' ) {
  57                                 if ( this.values[selection] === undefined ) {
  58                                         if ( fallback !== undefined ) {
  59                                                 return fallback;
  60                                         }
  61                                         return null;
  62                                 }
  63                                 return this.values[selection];
  64                         }
  65
  66                         if ( selection === undefined ) {
  67                                 return this.values;
  68                         }
  69
  70                         // invalid selection key
  71                         return null;
  72                 },
  73
  74                 /**
  75                  * Sets one or multiple key/value pairs.
  76                  *
  77                  * @param selection {mixed} String key or array of keys to set values for.
  78                  * @param value {mixed} Value to set (optional, only in use when key is a string)
  79                  * @return {Boolean} This returns true on success, false on failure.
  80                  */
  81                 set: function ( selection, value ) {
  82                         var s;
  83
  84                         if ( $.isPlainObject( selection ) ) {
  85                                 for ( s in selection ) {
  86                                         this.values[s] = selection[s];
  87                                 }
  88                                 return true;
  89                         }
  90                         if ( typeof selection === 'string' && value !== undefined ) {
  91                                 this.values[selection] = value;
  92                                 return true;
  93                         }
  94                         return false;
  95                 },
  96
  97                 /**
  98                  * Checks if one or multiple keys exist.
  99                  *
 100                  * @param selection {mixed} String key or array of keys to check
 101                  * @return {Boolean} Existence of key(s)
 102                  */
 103                 exists: function ( selection ) {
 104                         var s;
 105
 106                         if ( $.isArray( selection ) ) {
 107                                 for ( s = 0; s < selection.length; s += 1 ) {
 108                                         if ( this.values[selection[s]] === undefined ) {
 109                                                 return false;
 110                                         }
 111                                 }
 112                                 return true;
 113                         }
 114                         return this.values[selection] !== undefined;
 115                 }
 116         };
 117
 118         /**
 119          * Message
 120          *
 121          * Object constructor for messages,
 122          * similar to the Message class in MediaWiki PHP.
 123          *
 124          * @param map Map Instance of mw.Map
 125          * @param key String
 126          * @param parameters Array
 127          * @return Message
 128          */
 129         function Message( map, key, parameters ) {
 130                 this.format = 'text';
 131                 this.map = map;
 132                 this.key = key;
 133                 this.parameters = parameters === undefined ? [] : slice.call( parameters );
 134                 return this;
 135         }
 136
 137         Message.prototype = {
 138                 /**
 139                  * Simple message parser, does $N replacement, HTML-escaping (only for
 140                  * 'escaped' format), and nothing else.
 141                  *
 142                  * This may be overridden to provide a more complex message parser.
 143                  *
 144                  * The primary override is in mediawiki.jqueryMsg.
 145                  *
 146                  * This function will not be called for nonexistent messages.
 147                  */
 148                 parser: function () {
 149                         var parameters = this.parameters;
 150                         return this.map.get( this.key ).replace( /\$(\d+)/g, function ( str, match ) {
 151                                 var index = parseInt( match, 10 ) - 1;
 152                                 return parameters[index] !== undefined ? parameters[index] : '$' + match;
 153                         } );
 154                 },
 155
 156                 /**
 157                  * Appends (does not replace) parameters for replacement to the .parameters property.
 158                  *
 159                  * @param parameters Array
 160                  * @return Message
 161                  */
 162                 params: function ( parameters ) {
 163                         var i;
 164                         for ( i = 0; i < parameters.length; i += 1 ) {
 165                                 this.parameters.push( parameters[i] );
 166                         }
 167                         return this;
 168                 },
 169
 170                 /**
 171                  * Converts message object to it's string form based on the state of format.
 172                  *
 173                  * @return string Message as a string in the current form or <key> if key does not exist.
 174                  */
 175                 toString: function () {
 176                         var text;
 177
 178                         if ( !this.exists() ) {
 179                                 // Use <key> as text if key does not exist
 180                                 if ( this.format === 'escaped' || this.format === 'parse' ) {
 181                                         // format 'escaped' and 'parse' need to have the brackets and key html escaped
 182                                         return mw.html.escape( '<' + this.key + '>' );
 183                                 }
 184                                 return '<' + this.key + '>';
 185                         }
 186
 187                         if ( this.format === 'plain' || this.format === 'text' || this.format === 'parse' ) {
 188                                 text = this.parser();
 189                         }
 190
 191                         if ( this.format === 'escaped' ) {
 192                                 text = this.parser();
 193                                 text = mw.html.escape( text );
 194                         }
 195
 196                         return text;
 197                 },
 198
 199                 /**
 200                  * Changes format to 'parse' and converts message to string
 201                  *
 202                  * If jqueryMsg is loaded, this parses the message text from wikitext
 203                  * (where supported) to HTML
 204                  *
 205                  * Otherwise, it is equivalent to plain.
 206                  *
 207                  * @return {string} String form of parsed message
 208                  */
 209                 parse: function () {
 210                         this.format = 'parse';
 211                         return this.toString();
 212                 },
 213
 214                 /**
 215                  * Changes format to 'plain' and converts message to string
 216                  *
 217                  * This substitutes parameters, but otherwise does not change the
 218                  * message text.
 219                  *
 220                  * @return {string} String form of plain message
 221                  */
 222                 plain: function () {
 223                         this.format = 'plain';
 224                         return this.toString();
 225                 },
 226
 227                 /**
 228                  * Changes format to 'text' and converts message to string
 229                  *
 230                  * If jqueryMsg is loaded, {{-transformation is done where supported
 231                  * (such as {{plural:}}, {{gender:}}, {{int:}}).
 232                  *
 233                  * Otherwise, it is equivalent to plain.
 234                  */
 235                 text: function () {
 236                         this.format = 'text';
 237                         return this.toString();
 238                 },
 239
 240                 /**
 241                  * Changes the format to 'escaped' and converts message to string
 242                  *
 243                  * This is equivalent to using the 'text' format (see text method), then
 244                  * HTML-escaping the output.
 245                  *
 246                  * @return {string} String form of html escaped message
 247                  */
 248                 escaped: function () {
 249                         this.format = 'escaped';
 250                         return this.toString();
 251                 },
 252
 253                 /**
 254                  * Checks if message exists
 255                  *
 256                  * @return {string} String form of parsed message
 257                  */
 258                 exists: function () {
 259                         return this.map.exists( this.key );
 260                 }
 261         };
 262
 263         return {
 264                 /* Public Members */
 265
 266                 /**
 267                  * Dummy function which in debug mode can be replaced with a function that
 268                  * emulates console.log in console-less environments.
 269                  */
 270                 log: function () { },
 271
 272                 /**
 273                  * @var constructor Make the Map constructor publicly available.
 274                  */
 275                 Map: Map,
 276
 277                 /**
 278                  * @var constructor Make the Message constructor publicly available.
 279                  */
 280                 Message: Message,
 281
 282                 /**
 283                  * List of configuration values
 284                  *
 285                  * Dummy placeholder. Initiated in startUp module as a new instance of mw.Map().
 286                  * If $wgLegacyJavaScriptGlobals is true, this Map will have its values
 287                  * in the global window object.
 288                  */
 289                 config: null,
 290
 291                 /**
 292                  * @var object
 293                  *
 294                  * Empty object that plugins can be installed in.
 295                  */
 296                 libs: {},
 297
 298                 /* Extension points */
 299
 300                 legacy: {},
 301
 302                 /**
 303                  * Localization system
 304                  */
 305                 messages: new Map(),
 306
 307                 /* Public Methods */
 308
 309                 /**
 310                  * Gets a message object, similar to wfMessage()
 311                  *
 312                  * @param key string Key of message to get
 313                  * @param parameter1 mixed First argument in a list of variadic arguments,
 314                  *  each a parameter for $N replacement in messages.
 315                  * @return Message
 316                  */
 317                 message: function ( key, parameter1 ) {
 318                         var parameters;
 319                         // Support variadic arguments
 320                         if ( parameter1 !== undefined ) {
 321                                 parameters = slice.call( arguments );
 322                                 parameters.shift();
 323                         } else {
 324                                 parameters = [];
 325                         }
 326                         return new Message( mw.messages, key, parameters );
 327                 },
 328
 329                 /**
 330                  * Gets a message string, similar to wfMessage()
 331                  *
 332                  * @param key string Key of message to get
 333                  * @param parameters mixed First argument in a list of variadic arguments,
 334                  *  each a parameter for $N replacement in messages.
 335                  * @return String.
 336                  */
 337                 msg: function ( /* key, parameter_1, parameter_2, .. */ ) {
 338                         return mw.message.apply( mw.message, arguments ).toString();
 339                 },
 340
 341                 /**
 342                  * Client-side module loader which integrates with the MediaWiki ResourceLoader
 343                  */
 344                 loader: ( function () {
 345
 346                         /* Private Members */
 347
 348                         /**
 349                          * Mapping of registered modules
 350                          *
 351                          * The jquery module is pre-registered, because it must have already
 352                          * been provided for this object to have been built, and in debug mode
 353                          * jquery would have been provided through a unique loader request,
 354                          * making it impossible to hold back registration of jquery until after
 355                          * mediawiki.
 356                          *
 357                          * For exact details on support for script, style and messages, look at
 358                          * mw.loader.implement.
 359                          *
 360                          * Format:
 361                          *      {
 362                          *              'moduleName': {
 363                          *                      'version': ############## (unix timestamp),
 364                          *                      'dependencies': ['required.foo', 'bar.also', ...], (or) function () {}
 365                          *                      'group': 'somegroup', (or) null,
 366                          *                      'source': 'local', 'someforeignwiki', (or) null
 367                          *                      'state': 'registered', 'loading', 'loaded', 'ready', 'error' or 'missing'
 368                          *                      'script': ...,
 369                          *                      'style': ...,
 370                          *                      'messages': { 'key': 'value' },
 371                          *              }
 372                          *      }
 373                          */
 374                         var registry = {},
 375                                 /**
 376                                  * Mapping of sources, keyed by source-id, values are objects.
 377                                  * Format:
 378                                  *      {
 379                                  *              'sourceId': {
 380                                  *                      'loadScript': 'http://foo.bar/w/load.php'
 381                                  *              }
 382                                  *      }
 383                                  */
 384                                 sources = {},
 385                                 // List of modules which will be loaded as when ready
 386                                 batch = [],
 387                                 // List of modules to be loaded
 388                                 queue = [],
 389                                 // List of callback functions waiting for modules to be ready to be called
 390                                 jobs = [],
 391                                 // Selector cache for the marker element. Use getMarker() to get/use the marker!
 392                                 $marker = null;
 393
 394                         /* Private methods */
 395
 396                         function getMarker() {
 397                                 // Cached ?
 398                                 if ( $marker ) {
 399                                         return $marker;
 400                                 }
 401
 402                                 $marker = $( 'meta[name="ResourceLoaderDynamicStyles"]' );
 403                                 if ( $marker.length ) {
 404                                         return $marker;
 405                                 }
 406                                 mw.log( 'getMarker> No <meta name="ResourceLoaderDynamicStyles"> found, inserting dynamically.' );
 407                                 $marker = $( '<meta>' ).attr( 'name', 'ResourceLoaderDynamicStyles' ).appendTo( 'head' );
 408
 409                                 return $marker;
 410                         }
 411
 412                         /**
 413                          * Create a new style tag and add it to the DOM.
 414                          *
 415                          * @param text String: CSS text
 416                          * @param nextnode mixed: [optional] An Element or jQuery object for an element where
 417                          * the style tag should be inserted before. Otherwise appended to the <head>.
 418                          * @return HTMLStyleElement
 419                          */
 420                         function addStyleTag( text, nextnode ) {
 421                                 var s = document.createElement( 'style' );
 422                                 // Insert into document before setting cssText (bug 33305)
 423                                 if ( nextnode ) {
 424                                         // Must be inserted with native insertBefore, not $.fn.before.
 425                                         // When using jQuery to insert it, like $nextnode.before( s ),
 426                                         // then IE6 will throw "Access is denied" when trying to append
 427                                         // to .cssText later. Some kind of weird security measure.
 428                                         // http://stackoverflow.com/q/12586482/319266
 429                                         // Works: jsfiddle.net/zJzMy/1
 430                                         // Fails: jsfiddle.net/uJTQz
 431                                         // Works again: http://jsfiddle.net/Azr4w/ (diff: the next 3 lines)
 432                                         if ( nextnode.jquery ) {
 433                                                 nextnode = nextnode.get( 0 );
 434                                         }
 435                                         nextnode.parentNode.insertBefore( s, nextnode );
 436                                 } else {
 437                                         document.getElementsByTagName( 'head' )[0].appendChild( s );
 438                                 }
 439                                 if ( s.styleSheet ) {
 440                                         // IE
 441                                         s.styleSheet.cssText = text;
 442                                 } else {
 443                                         // Other browsers.
 444                                         // (Safari sometimes borks on non-string values,
 445                                         // play safe by casting to a string, just in case.)
 446                                         s.appendChild( document.createTextNode( String( text ) ) );
 447                                 }
 448                                 return s;
 449                         }
 450
 451                         /**
 452                          * Checks if certain cssText is safe to append to
 453                          * a stylesheet.
 454                          *
 455                          * Right now it only makes sure that cssText containing @import
 456                          * rules will end up in a new stylesheet (as those only work when
 457                          * placed at the start of a stylesheet; bug 35562).
 458                          * This could later be extended to take care of other bugs, such as
 459                          * the IE cssRules limit - not the same as the IE styleSheets limit).
 460                          */
 461                         function canExpandStylesheetWith( $style, cssText ) {
 462                                 return cssText.indexOf( '@import' ) === -1;
 463                         }
 464
 465                         function addEmbeddedCSS( cssText ) {
 466                                 var $style, styleEl;
 467                                 $style = getMarker().prev();
 468                                 // Re-use <style> tags if possible, this to try to stay
 469                                 // under the IE stylesheet limit (bug 31676).
 470                                 // Also verify that the the element before Marker actually is one
 471                                 // that came from ResourceLoader, and not a style tag that some
 472                                 // other script inserted before our marker, or, more importantly,
 473                                 // it may not be a style tag at all (could be <meta> or <script>).
 474                                 if (
 475                                         $style.data( 'ResourceLoaderDynamicStyleTag' ) === true &&
 476                                         canExpandStylesheetWith( $style, cssText )
 477                                 ) {
 478                                         // There's already a dynamic <style> tag present and
 479                                         // canExpandStylesheetWith() gave a green light to append more to it.
 480                                         styleEl = $style.get( 0 );
 481                                         if ( styleEl.styleSheet ) {
 482                                                 try {
 483                                                         styleEl.styleSheet.cssText += cssText; // IE
 484                                                 } catch ( e ) {
 485                                                         log( 'addEmbeddedCSS fail\ne.message: ' + e.message, e );
 486                                                 }
 487                                         } else {
 488                                                 styleEl.appendChild( document.createTextNode( String( cssText ) ) );
 489                                         }
 490                                 } else {
 491                                         $( addStyleTag( cssText, getMarker() ) )
 492                                                 .data( 'ResourceLoaderDynamicStyleTag', true );
 493                                 }
 494                         }
 495
 496                         /**
 497                          * Generates an ISO8601 "basic" string from a UNIX timestamp
 498                          */
 499                         function formatVersionNumber( timestamp ) {
 500                                 var     d = new Date();
 501                                 function pad( a, b, c ) {
 502                                         return [a < 10 ? '0' + a : a, b < 10 ? '0' + b : b, c < 10 ? '0' + c : c].join( '' );
 503                                 }
 504                                 d.setTime( timestamp * 1000 );
 505                                 return [
 506                                         pad( d.getUTCFullYear(), d.getUTCMonth() + 1, d.getUTCDate() ), 'T',
 507                                         pad( d.getUTCHours(), d.getUTCMinutes(), d.getUTCSeconds() ), 'Z'
 508                                 ].join( '' );
 509                         }
 510
 511                         /**
 512                          * Resolves dependencies and detects circular references.
 513                          *
 514                          * @param module String Name of the top-level module whose dependencies shall be
 515                          *   resolved and sorted.
 516                          * @param resolved Array Returns a topological sort of the given module and its
 517                          *   dependencies, such that later modules depend on earlier modules. The array
 518                          *   contains the module names. If the array contains already some module names,
 519                          *   this function appends its result to the pre-existing array.
 520                          * @param unresolved Object [optional] Hash used to track the current dependency
 521                          *   chain; used to report loops in the dependency graph.
 522                          * @throws Error if any unregistered module or a dependency loop is encountered
 523                          */
 524                         function sortDependencies( module, resolved, unresolved ) {
 525                                 var n, deps, len;
 526
 527                                 if ( registry[module] === undefined ) {
 528                                         throw new Error( 'Unknown dependency: ' + module );
 529                                 }
 530                                 // Resolves dynamic loader function and replaces it with its own results
 531                                 if ( $.isFunction( registry[module].dependencies ) ) {
 532                                         registry[module].dependencies = registry[module].dependencies();
 533                                         // Ensures the module's dependencies are always in an array
 534                                         if ( typeof registry[module].dependencies !== 'object' ) {
 535                                                 registry[module].dependencies = [registry[module].dependencies];
 536                                         }
 537                                 }
 538                                 if ( $.inArray( module, resolved ) !== -1 ) {
 539                                         // Module already resolved; nothing to do.
 540                                         return;
 541                                 }
 542                                 // unresolved is optional, supply it if not passed in
 543                                 if ( !unresolved ) {
 544                                         unresolved = {};
 545                                 }
 546                                 // Tracks down dependencies
 547                                 deps = registry[module].dependencies;
 548                                 len = deps.length;
 549                                 for ( n = 0; n < len; n += 1 ) {
 550                                         if ( $.inArray( deps[n], resolved ) === -1 ) {
 551                                                 if ( unresolved[deps[n]] ) {
 552                                                         throw new Error(
 553                                                                 'Circular reference detected: ' + module +
 554                                                                 ' -> ' + deps[n]
 555                                                         );
 556                                                 }
 557
 558                                                 // Add to unresolved
 559                                                 unresolved[module] = true;
 560                                                 sortDependencies( deps[n], resolved, unresolved );
 561                                                 delete unresolved[module];
 562                                         }
 563                                 }
 564                                 resolved[resolved.length] = module;
 565                         }
 566
 567                         /**
 568                          * Gets a list of module names that a module depends on in their proper dependency
 569                          * order.
 570                          *
 571                          * @param module string module name or array of string module names
 572                          * @return list of dependencies, including 'module'.
 573                          * @throws Error if circular reference is detected
 574                          */
 575                         function resolve( module ) {
 576                                 var m, resolved;
 577
 578                                 // Allow calling with an array of module names
 579                                 if ( $.isArray( module ) ) {
 580                                         resolved = [];
 581                                         for ( m = 0; m < module.length; m += 1 ) {
 582                                                 sortDependencies( module[m], resolved );
 583                                         }
 584                                         return resolved;
 585                                 }
 586
 587                                 if ( typeof module === 'string' ) {
 588                                         resolved = [];
 589                                         sortDependencies( module, resolved );
 590                                         return resolved;
 591                                 }
 592
 593                                 throw new Error( 'Invalid module argument: ' + module );
 594                         }
 595
 596                         /**
 597                          * Narrows a list of module names down to those matching a specific
 598                          * state (see comment on top of this scope for a list of valid states).
 599                          * One can also filter for 'unregistered', which will return the
 600                          * modules names that don't have a registry entry.
 601                          *
 602                          * @param states string or array of strings of module states to filter by
 603                          * @param modules array list of module names to filter (optional, by default the entire
 604                          * registry is used)
 605                          * @return array list of filtered module names
 606                          */
 607                         function filter( states, modules ) {
 608                                 var list, module, s, m;
 609
 610                                 // Allow states to be given as a string
 611                                 if ( typeof states === 'string' ) {
 612                                         states = [states];
 613                                 }
 614                                 // If called without a list of modules, build and use a list of all modules
 615                                 list = [];
 616                                 if ( modules === undefined ) {
 617                                         modules = [];
 618                                         for ( module in registry ) {
 619                                                 modules[modules.length] = module;
 620                                         }
 621                                 }
 622                                 // Build a list of modules which are in one of the specified states
 623                                 for ( s = 0; s < states.length; s += 1 ) {
 624                                         for ( m = 0; m < modules.length; m += 1 ) {
 625                                                 if ( registry[modules[m]] === undefined ) {
 626                                                         // Module does not exist
 627                                                         if ( states[s] === 'unregistered' ) {
 628                                                                 // OK, undefined
 629                                                                 list[list.length] = modules[m];
 630                                                         }
 631                                                 } else {
 632                                                         // Module exists, check state
 633                                                         if ( registry[modules[m]].state === states[s] ) {
 634                                                                 // OK, correct state
 635                                                                 list[list.length] = modules[m];
 636                                                         }
 637                                                 }
 638                                         }
 639                                 }
 640                                 return list;
 641                         }
 642
 643                         /**
 644                          * Determine whether all dependencies are in state 'ready', which means we may
 645                          * execute the module or job now.
 646                          *
 647                          * @param dependencies Array dependencies (module names) to be checked.
 648                          *
 649                          * @return Boolean true if all dependencies are in state 'ready', false otherwise
 650                          */
 651                         function allReady( dependencies ) {
 652                                 return filter( 'ready', dependencies ).length === dependencies.length;
 653                         }
 654
 655                         /**
 656                          * Log a message to window.console, if possible. Useful to force logging of some
 657                          * errors that are otherwise hard to detect (I.e., this logs also in production mode).
 658                          * Gets console references in each invocation, so that delayed debugging tools work
 659                          * fine. No need for optimization here, which would only result in losing logs.
 660                          *
 661                          * @param msg String text for the log entry.
 662                          * @param e Error [optional] to also log.
 663                          */
 664                         function log( msg, e ) {
 665                                 var console = window.console;
 666                                 if ( console && console.log ) {
 667                                         console.log( msg );
 668                                         // If we have an exception object, log it through .error() to trigger
 669                                         // proper stacktraces in browsers that support it. There are no (known)
 670                                         // browsers that don't support .error(), that do support .log() and
 671                                         // have useful exception handling through .log().
 672                                         if ( e && console.error ) {
 673                                                 console.error( e );
 674                                         }
 675                                 }
 676                         }
 677
 678                         /**
 679                          * A module has entered state 'ready', 'error', or 'missing'. Automatically update pending jobs
 680                          * and modules that depend upon this module. if the given module failed, propagate the 'error'
 681                          * state up the dependency tree; otherwise, execute all jobs/modules that now have all their
 682                          * dependencies satisfied. On jobs depending on a failed module, run the error callback, if any.
 683                          *
 684                          * @param module String name of module that entered one of the states 'ready', 'error', or 'missing'.
 685                          */
 686                         function handlePending( module ) {
 687                                 var j, job, hasErrors, m, stateChange;
 688
 689                                 // Modules.
 690                                 if ( $.inArray( registry[module].state, ['error', 'missing'] ) !== -1 ) {
 691                                         // If the current module failed, mark all dependent modules also as failed.
 692                                         // Iterate until steady-state to propagate the error state upwards in the
 693                                         // dependency tree.
 694                                         do {
 695                                                 stateChange = false;
 696                                                 for ( m in registry ) {
 697                                                         if ( $.inArray( registry[m].state, ['error', 'missing'] ) === -1 ) {
 698                                                                 if ( filter( ['error', 'missing'], registry[m].dependencies ).length > 0 ) {
 699                                                                         registry[m].state = 'error';
 700                                                                         stateChange = true;
 701                                                                 }
 702                                                         }
 703                                                 }
 704                                         } while ( stateChange );
 705                                 }
 706
 707                                 // Execute all jobs whose dependencies are either all satisfied or contain at least one failed module.
 708                                 for ( j = 0; j < jobs.length; j += 1 ) {
 709                                         hasErrors = filter( ['error', 'missing'], jobs[j].dependencies ).length > 0;
 710                                         if ( hasErrors || allReady( jobs[j].dependencies ) ) {
 711                                                 // All dependencies satisfied, or some have errors
 712                                                 job = jobs[j];
 713                                                 jobs.splice( j, 1 );
 714                                                 j -= 1;
 715                                                 try {
 716                                                         if ( hasErrors ) {
 717                                                                 throw new Error( 'Module ' + module + ' failed.');
 718                                                         } else {
 719                                                                 if ( $.isFunction( job.ready ) ) {
 720                                                                         job.ready();
 721                                                                 }
 722                                                         }
 723                                                 } catch ( e ) {
 724                                                         if ( $.isFunction( job.error ) ) {
 725                                                                 try {
 726                                                                         job.error( e, [module] );
 727                                                                 } catch ( ex ) {
 728                                                                         // A user-defined operation raised an exception. Swallow to protect
 729                                                                         // our state machine!
 730                                                                         log( 'Exception thrown by job.error()', ex );
 731                                                                 }
 732                                                         }
 733                                                 }
 734                                         }
 735                                 }
 736
 737                                 if ( registry[module].state === 'ready' ) {
 738                                         // The current module became 'ready'. Recursively execute all dependent modules that are loaded
 739                                         // and now have all dependencies satisfied.
 740                                         for ( m in registry ) {
 741                                                 if ( registry[m].state === 'loaded' && allReady( registry[m].dependencies ) ) {
 742                                                         execute( m );
 743                                                 }
 744                                         }
 745                                 }
 746                         }
 747
 748                         /**
 749                          * Adds a script tag to the DOM, either using document.write or low-level DOM manipulation,
 750                          * depending on whether document-ready has occurred yet and whether we are in async mode.
 751                          *
 752                          * @param src String: URL to script, will be used as the src attribute in the script tag
 753                          * @param callback Function: Optional callback which will be run when the script is done
 754                          */
 755                         function addScript( src, callback, async ) {
 756                                 /*jshint evil:true */
 757                                 var script, head,
 758                                         done = false;
 759
 760                                 // Using isReady directly instead of storing it locally from
 761                                 // a $.fn.ready callback (bug 31895).
 762                                 if ( $.isReady || async ) {
 763                                         // Can't use jQuery.getScript because that only uses <script> for cross-domain,
 764                                         // it uses XHR and eval for same-domain scripts, which we don't want because it
 765                                         // messes up line numbers.
 766                                         // The below is based on jQuery ([jquery@1.8.2]/src/ajax/script.js)
 767
 768                                         // IE-safe way of getting the <head>. document.head isn't supported
 769                                         // in old IE, and doesn't work when in the <head>.
 770                                         head = document.getElementsByTagName( 'head' )[0] || document.body;
 771
 772                                         script = document.createElement( 'script' );
 773                                         script.async = true;
 774                                         script.src = src;
 775                                         if ( $.isFunction( callback ) ) {
 776                                                 script.onload = script.onreadystatechange = function () {
 777                                                         if (
 778                                                                 !done
 779                                                                 && (
 780                                                                         !script.readyState
 781                                                                         || /loaded|complete/.test( script.readyState )
 782                                                                 )
 783                                                         ) {
 784                                                                 done = true;
 785
 786                                                                 // Handle memory leak in IE
 787                                                                 script.onload = script.onreadystatechange = null;
 788
 789                                                                 // Remove the script
 790                                                                 if ( script.parentNode ) {
 791                                                                         script.parentNode.removeChild( script );
 792                                                                 }
 793
 794                                                                 // Dereference the script
 795                                                                 script = undefined;
 796
 797                                                                 callback();
 798                                                         }
 799                                                 };
 800                                         }
 801
 802                                         if ( window.opera ) {
 803                                                 // Appending to the <head> blocks rendering completely in Opera,
 804                                                 // so append to the <body> after document ready. This means the
 805                                                 // scripts only start loading after the document has been rendered,
 806                                                 // but so be it. Opera users don't deserve faster web pages if their
 807                                                 // browser makes it impossible.
 808                                                 $( function () {
 809                                                         document.body.appendChild( script );
 810                                                 } );
 811                                         } else {
 812                                                 head.appendChild( script );
 813                                         }
 814                                 } else {
 815                                         document.write( mw.html.element( 'script', { 'src': src }, '' ) );
 816                                         if ( $.isFunction( callback ) ) {
 817                                                 // Document.write is synchronous, so this is called when it's done
 818                                                 // FIXME: that's a lie. doc.write isn't actually synchronous
 819                                                 callback();
 820                                         }
 821                                 }
 822                         }
 823
 824                         /**
 825                          * Executes a loaded module, making it ready to use
 826                          *
 827                          * @param module string module name to execute
 828                          */
 829                         function execute( module ) {
 830                                 var key, value, media, i, urls, script, markModuleReady, nestedAddScript;
 831
 832                                 if ( registry[module] === undefined ) {
 833                                         throw new Error( 'Module has not been registered yet: ' + module );
 834                                 } else if ( registry[module].state === 'registered' ) {
 835                                         throw new Error( 'Module has not been requested from the server yet: ' + module );
 836                                 } else if ( registry[module].state === 'loading' ) {
 837                                         throw new Error( 'Module has not completed loading yet: ' + module );
 838                                 } else if ( registry[module].state === 'ready' ) {
 839                                         throw new Error( 'Module has already been loaded: ' + module );
 840                                 }
 841
 842                                 /**
 843                                  * Define loop-function here for efficiency
 844                                  * and to avoid re-using badly scoped variables.
 845                                  */
 846                                 function addLink( media, url ) {
 847                                         var el = document.createElement( 'link' );
 848                                         getMarker().before( el ); // IE: Insert in dom before setting href
 849                                         el.rel = 'stylesheet';
 850                                         if ( media && media !== 'all' ) {
 851                                                 el.media = media;
 852                                         }
 853                                         el.href = url;
 854                                 }
 855
 856                                 // Process styles (see also mw.loader.implement)
 857                                 // * back-compat: { <media>: css }
 858                                 // * back-compat: { <media>: [url, ..] }
 859                                 // * { "css": [css, ..] }
 860                                 // * { "url": { <media>: [url, ..] } }
 861                                 if ( $.isPlainObject( registry[module].style ) ) {
 862                                         for ( key in registry[module].style ) {
 863                                                 value = registry[module].style[key];
 864                                                 media = undefined;
 865
 866                                                 if ( key !== 'url' && key !== 'css' ) {
 867                                                         // Backwards compatibility, key is a media-type
 868                                                         if ( typeof value === 'string' ) {
 869                                                                 // back-compat: { <media>: css }
 870                                                                 // Ignore 'media' because it isn't supported (nor was it used).
 871                                                                 // Strings are pre-wrapped in "@media". The media-type was just ""
 872                                                                 // (because it had to be set to something).
 873                                                                 // This is one of the reasons why this format is no longer used.
 874                                                                 addEmbeddedCSS( value );
 875                                                         } else {
 876                                                                 // back-compat: { <media>: [url, ..] }
 877                                                                 media = key;
 878                                                                 key = 'bc-url';
 879                                                         }
 880                                                 }
 881
 882                                                 // Array of css strings in key 'css',
 883                                                 // or back-compat array of urls from media-type
 884                                                 if ( $.isArray( value ) ) {
 885                                                         for ( i = 0; i < value.length; i += 1 ) {
 886                                                                 if ( key === 'bc-url' ) {
 887                                                                         // back-compat: { <media>: [url, ..] }
 888                                                                         addLink( media, value[i] );
 889                                                                 } else if ( key === 'css' ) {
 890                                                                         // { "css": [css, ..] }
 891                                                                         addEmbeddedCSS( value[i] );
 892                                                                 }
 893                                                         }
 894                                                 // Not an array, but a regular object
 895                                                 // Array of urls inside media-type key
 896                                                 } else if ( typeof value === 'object' ) {
 897                                                         // { "url": { <media>: [url, ..] } }
 898                                                         for ( media in value ) {
 899                                                                 urls = value[media];
 900                                                                 for ( i = 0; i < urls.length; i += 1 ) {
 901                                                                         addLink( media, urls[i] );
 902                                                                 }
 903                                                         }
 904                                                 }
 905                                         }
 906                                 }
 907
 908                                 // Add localizations to message system
 909                                 if ( $.isPlainObject( registry[module].messages ) ) {
 910                                         mw.messages.set( registry[module].messages );
 911                                 }
 912
 913                                 // Execute script
 914                                 try {
 915                                         script = registry[module].script;
 916                                         markModuleReady = function () {
 917                                                 registry[module].state = 'ready';
 918                                                 handlePending( module );
 919                                         };
 920                                         nestedAddScript = function ( arr, callback, async, i ) {
 921                                                 // Recursively call addScript() in its own callback
 922                                                 // for each element of arr.
 923                                                 if ( i >= arr.length ) {
 924                                                         // We're at the end of the array
 925                                                         callback();
 926                                                         return;
 927                                                 }
 928
 929                                                 addScript( arr[i], function () {
 930                                                         nestedAddScript( arr, callback, async, i + 1 );
 931                                                 }, async );
 932                                         };
 933
 934                                         if ( $.isArray( script ) ) {
 935                                                 registry[module].state = 'loading';
 936                                                 nestedAddScript( script, markModuleReady, registry[module].async, 0 );
 937                                         } else if ( $.isFunction( script ) ) {
 938                                                 registry[module].state = 'ready';
 939                                                 script( $ );
 940                                                 handlePending( module );
 941                                         }
 942                                 } catch ( e ) {
 943                                         // This needs to NOT use mw.log because these errors are common in production mode
 944                                         // and not in debug mode, such as when a symbol that should be global isn't exported
 945                                         log( 'Exception thrown by ' + module + ': ' + e.message, e );
 946                                         registry[module].state = 'error';
 947                                         handlePending( module );
 948                                 }
 949                         }
 950
 951                         /**
 952                          * Adds a dependencies to the queue with optional callbacks to be run
 953                          * when the dependencies are ready or fail
 954                          *
 955                          * @param dependencies string module name or array of string module names
 956                          * @param ready function callback to execute when all dependencies are ready
 957                          * @param error function callback to execute when any dependency fails
 958                          * @param async (optional) If true, load modules asynchronously even if
 959                          *  document ready has not yet occurred
 960                          */
 961                         function request( dependencies, ready, error, async ) {
 962                                 var n;
 963
 964                                 // Allow calling by single module name
 965                                 if ( typeof dependencies === 'string' ) {
 966                                         dependencies = [dependencies];
 967                                 }
 968
 969                                 // Add ready and error callbacks if they were given
 970                                 if ( ready !== undefined || error !== undefined ) {
 971                                         jobs[jobs.length] = {
 972                                                 'dependencies': filter(
 973                                                         ['registered', 'loading', 'loaded'],
 974                                                         dependencies
 975                                                 ),
 976                                                 'ready': ready,
 977                                                 'error': error
 978                                         };
 979                                 }
 980
 981                                 // Queue up any dependencies that are registered
 982                                 dependencies = filter( ['registered'], dependencies );
 983                                 for ( n = 0; n < dependencies.length; n += 1 ) {
 984                                         if ( $.inArray( dependencies[n], queue ) === -1 ) {
 985                                                 queue[queue.length] = dependencies[n];
 986                                                 if ( async ) {
 987                                                         // Mark this module as async in the registry
 988                                                         registry[dependencies[n]].async = true;
 989                                                 }
 990                                         }
 991                                 }
 992
 993                                 // Work the queue
 994                                 mw.loader.work();
 995                         }
 996
 997                         function sortQuery(o) {
 998                                 var sorted = {}, key, a = [];
 999                                 for ( key in o ) {
1000                                         if ( hasOwn.call( o, key ) ) {
1001                                                 a.push( key );
1002                                         }
1003                                 }
1004                                 a.sort();
1005                                 for ( key = 0; key < a.length; key += 1 ) {
1006                                         sorted[a[key]] = o[a[key]];
1007                                 }
1008                                 return sorted;
1009                         }
1010
1011                         /**
1012                          * Converts a module map of the form { foo: [ 'bar', 'baz' ], bar: [ 'baz, 'quux' ] }
1013                          * to a query string of the form foo.bar,baz|bar.baz,quux
1014                          */
1015                         function buildModulesString( moduleMap ) {
1016                                 var arr = [], p, prefix;
1017                                 for ( prefix in moduleMap ) {
1018                                         p = prefix === '' ? '' : prefix + '.';
1019                                         arr.push( p + moduleMap[prefix].join( ',' ) );
1020                                 }
1021                                 return arr.join( '|' );
1022                         }
1023
1024                         /**
1025                          * Asynchronously append a script tag to the end of the body
1026                          * that invokes load.php
1027                          * @param moduleMap {Object}: Module map, see buildModulesString()
1028                          * @param currReqBase {Object}: Object with other parameters (other than 'modules') to use in the request
1029                          * @param sourceLoadScript {String}: URL of load.php
1030                          * @param async {Boolean}: If true, use an asynchrounous request even if document ready has not yet occurred
1031                          */
1032                         function doRequest( moduleMap, currReqBase, sourceLoadScript, async ) {
1033                                 var request = $.extend(
1034                                         { modules: buildModulesString( moduleMap ) },
1035                                         currReqBase
1036                                 );
1037                                 request = sortQuery( request );
1038                                 // Asynchronously append a script tag to the end of the body
1039                                 // Append &* to avoid triggering the IE6 extension check
1040                                 addScript( sourceLoadScript + '?' + $.param( request ) + '&*', null, async );
1041                         }
1042
1043                         /* Public Methods */
1044                         return {
1045                                 addStyleTag: addStyleTag,
1046
1047                                 /**
1048                                  * Requests dependencies from server, loading and executing when things when ready.
1049                                  */
1050                                 work: function () {
1051                                         var     reqBase, splits, maxQueryLength, q, b, bSource, bGroup, bSourceGroup,
1052                                                 source, group, g, i, modules, maxVersion, sourceLoadScript,
1053                                                 currReqBase, currReqBaseLength, moduleMap, l,
1054                                                 lastDotIndex, prefix, suffix, bytesAdded, async;
1055
1056                                         // Build a list of request parameters common to all requests.
1057                                         reqBase = {
1058                                                 skin: mw.config.get( 'skin' ),
1059                                                 lang: mw.config.get( 'wgUserLanguage' ),
1060                                                 debug: mw.config.get( 'debug' )
1061                                         };
1062                                         // Split module batch by source and by group.
1063                                         splits = {};
1064                                         maxQueryLength = mw.config.get( 'wgResourceLoaderMaxQueryLength', -1 );
1065
1066                                         // Appends a list of modules from the queue to the batch
1067                                         for ( q = 0; q < queue.length; q += 1 ) {
1068                                                 // Only request modules which are registered
1069                                                 if ( registry[queue[q]] !== undefined && registry[queue[q]].state === 'registered' ) {
1070                                                         // Prevent duplicate entries
1071                                                         if ( $.inArray( queue[q], batch ) === -1 ) {
1072                                                                 batch[batch.length] = queue[q];
1073                                                                 // Mark registered modules as loading
1074                                                                 registry[queue[q]].state = 'loading';
1075                                                         }
1076                                                 }
1077                                         }
1078                                         // Early exit if there's nothing to load...
1079                                         if ( !batch.length ) {
1080                                                 return;
1081                                         }
1082
1083                                         // The queue has been processed into the batch, clear up the queue.
1084                                         queue = [];
1085
1086                                         // Always order modules alphabetically to help reduce cache
1087                                         // misses for otherwise identical content.
1088                                         batch.sort();
1089
1090                                         // Split batch by source and by group.
1091                                         for ( b = 0; b < batch.length; b += 1 ) {
1092                                                 bSource = registry[batch[b]].source;
1093                                                 bGroup = registry[batch[b]].group;
1094                                                 if ( splits[bSource] === undefined ) {
1095                                                         splits[bSource] = {};
1096                                                 }
1097                                                 if ( splits[bSource][bGroup] === undefined ) {
1098                                                         splits[bSource][bGroup] = [];
1099                                                 }
1100                                                 bSourceGroup = splits[bSource][bGroup];
1101                                                 bSourceGroup[bSourceGroup.length] = batch[b];
1102                                         }
1103
1104                                         // Clear the batch - this MUST happen before we append any
1105                                         // script elements to the body or it's possible that a script
1106                                         // will be locally cached, instantly load, and work the batch
1107                                         // again, all before we've cleared it causing each request to
1108                                         // include modules which are already loaded.
1109                                         batch = [];
1110
1111                                         for ( source in splits ) {
1112
1113                                                 sourceLoadScript = sources[source].loadScript;
1114
1115                                                 for ( group in splits[source] ) {
1116
1117                                                         // Cache access to currently selected list of
1118                                                         // modules for this group from this source.
1119                                                         modules = splits[source][group];
1120
1121                                                         // Calculate the highest timestamp
1122                                                         maxVersion = 0;
1123                                                         for ( g = 0; g < modules.length; g += 1 ) {
1124                                                                 if ( registry[modules[g]].version > maxVersion ) {
1125                                                                         maxVersion = registry[modules[g]].version;
1126                                                                 }
1127                                                         }
1128
1129                                                         currReqBase = $.extend( { version: formatVersionNumber( maxVersion ) }, reqBase );
1130                                                         // For user modules append a user name to the request.
1131                                                         if ( group === 'user' && mw.config.get( 'wgUserName' ) !== null ) {
1132                                                                 currReqBase.user = mw.config.get( 'wgUserName' );
1133                                                         }
1134                                                         currReqBaseLength = $.param( currReqBase ).length;
1135                                                         async = true;
1136                                                         // We may need to split up the request to honor the query string length limit,
1137                                                         // so build it piece by piece.
1138                                                         l = currReqBaseLength + 9; // '&modules='.length == 9
1139
1140                                                         moduleMap = {}; // { prefix: [ suffixes ] }
1141
1142                                                         for ( i = 0; i < modules.length; i += 1 ) {
1143                                                                 // Determine how many bytes this module would add to the query string
1144                                                                 lastDotIndex = modules[i].lastIndexOf( '.' );
1145                                                                 // Note that these substr() calls work even if lastDotIndex == -1
1146                                                                 prefix = modules[i].substr( 0, lastDotIndex );
1147                                                                 suffix = modules[i].substr( lastDotIndex + 1 );
1148                                                                 bytesAdded = moduleMap[prefix] !== undefined
1149                                                                         ? suffix.length + 3 // '%2C'.length == 3
1150                                                                         : modules[i].length + 3; // '%7C'.length == 3
1151
1152                                                                 // If the request would become too long, create a new one,
1153                                                                 // but don't create empty requests
1154                                                                 if ( maxQueryLength > 0 && !$.isEmptyObject( moduleMap ) && l + bytesAdded > maxQueryLength ) {
1155                                                                         // This request would become too long, create a new one
1156                                                                         // and fire off the old one
1157                                                                         doRequest( moduleMap, currReqBase, sourceLoadScript, async );
1158                                                                         moduleMap = {};
1159                                                                         async = true;
1160                                                                         l = currReqBaseLength + 9;
1161                                                                 }
1162                                                                 if ( moduleMap[prefix] === undefined ) {
1163                                                                         moduleMap[prefix] = [];
1164                                                                 }
1165                                                                 moduleMap[prefix].push( suffix );
1166                                                                 if ( !registry[modules[i]].async ) {
1167                                                                         // If this module is blocking, make the entire request blocking
1168                                                                         // This is slightly suboptimal, but in practice mixing of blocking
1169                                                                         // and async modules will only occur in debug mode.
1170                                                                         async = false;
1171                                                                 }
1172                                                                 l += bytesAdded;
1173                                                         }
1174                                                         // If there's anything left in moduleMap, request that too
1175                                                         if ( !$.isEmptyObject( moduleMap ) ) {
1176                                                                 doRequest( moduleMap, currReqBase, sourceLoadScript, async );
1177                                                         }
1178                                                 }
1179                                         }
1180                                 },
1181
1182                                 /**
1183                                  * Register a source.
1184                                  *
1185                                  * @param id {String}: Short lowercase a-Z string representing a source, only used internally.
1186                                  * @param props {Object}: Object containing only the loadScript property which is a url to
1187                                  * the load.php location of the source.
1188                                  * @return {Boolean}
1189                                  */
1190                                 addSource: function ( id, props ) {
1191                                         var source;
1192                                         // Allow multiple additions
1193                                         if ( typeof id === 'object' ) {
1194                                                 for ( source in id ) {
1195                                                         mw.loader.addSource( source, id[source] );
1196                                                 }
1197                                                 return true;
1198                                         }
1199
1200                                         if ( sources[id] !== undefined ) {
1201                                                 throw new Error( 'source already registered: ' + id );
1202                                         }
1203
1204                                         sources[id] = props;
1205
1206                                         return true;
1207                                 },
1208
1209                                 /**
1210                                  * Registers a module, letting the system know about it and its
1211                                  * properties. Startup modules contain calls to this function.
1212                                  *
1213                                  * @param module {String}: Module name
1214                                  * @param version {Number}: Module version number as a timestamp (falls backs to 0)
1215                                  * @param dependencies {String|Array|Function}: One string or array of strings of module
1216                                  *  names on which this module depends, or a function that returns that array.
1217                                  * @param group {String}: Group which the module is in (optional, defaults to null)
1218                                  * @param source {String}: Name of the source. Defaults to local.
1219                                  */
1220                                 register: function ( module, version, dependencies, group, source ) {
1221                                         var m;
1222                                         // Allow multiple registration
1223                                         if ( typeof module === 'object' ) {
1224                                                 for ( m = 0; m < module.length; m += 1 ) {
1225                                                         // module is an array of module names
1226                                                         if ( typeof module[m] === 'string' ) {
1227                                                                 mw.loader.register( module[m] );
1228                                                         // module is an array of arrays
1229                                                         } else if ( typeof module[m] === 'object' ) {
1230                                                                 mw.loader.register.apply( mw.loader, module[m] );
1231                                                         }
1232                                                 }
1233                                                 return;
1234                                         }
1235                                         // Validate input
1236                                         if ( typeof module !== 'string' ) {
1237                                                 throw new Error( 'module must be a string, not a ' + typeof module );
1238                                         }
1239                                         if ( registry[module] !== undefined ) {
1240                                                 throw new Error( 'module already registered: ' + module );
1241                                         }
1242                                         // List the module as registered
1243                                         registry[module] = {
1244                                                 version: version !== undefined ? parseInt( version, 10 ) : 0,
1245                                                 dependencies: [],
1246                                                 group: typeof group === 'string' ? group : null,
1247                                                 source: typeof source === 'string' ? source: 'local',
1248                                                 state: 'registered'
1249                                         };
1250                                         if ( typeof dependencies === 'string' ) {
1251                                                 // Allow dependencies to be given as a single module name
1252                                                 registry[module].dependencies = [ dependencies ];
1253                                         } else if ( typeof dependencies === 'object' || $.isFunction( dependencies ) ) {
1254                                                 // Allow dependencies to be given as an array of module names
1255                                                 // or a function which returns an array
1256                                                 registry[module].dependencies = dependencies;
1257                                         }
1258                                 },
1259
1260                                 /**
1261                                  * Implements a module, giving the system a course of action to take
1262                                  * upon loading. Results of a request for one or more modules contain
1263                                  * calls to this function.
1264                                  *
1265                                  * All arguments are required.
1266                                  *
1267                                  * @param {String} module Name of module
1268                                  * @param {Function|Array} script Function with module code or Array of URLs to
1269                                  *  be used as the src attribute of a new <script> tag.
1270                                  * @param {Object} style Should follow one of the following patterns:
1271                                  *  { "css": [css, ..] }
1272                                  *  { "url": { <media>: [url, ..] } }
1273                                  *  And for backwards compatibility (needs to be supported forever due to caching):
1274                                  *  { <media>: css }
1275                                  *  { <media>: [url, ..] }
1276                                  *
1277                                  *  The reason css strings are not concatenated anymore is bug 31676. We now check
1278                                  *  whether it's safe to extend the stylesheet (see canExpandStylesheetWith).
1279                                  *
1280                                  * @param {Object} msgs List of key/value pairs to be passed through mw.messages.set
1281                                  */
1282                                 implement: function ( module, script, style, msgs ) {
1283                                         // Validate input
1284                                         if ( typeof module !== 'string' ) {
1285                                                 throw new Error( 'module must be a string, not a ' + typeof module );
1286                                         }
1287                                         if ( !$.isFunction( script ) && !$.isArray( script ) ) {
1288                                                 throw new Error( 'script must be a function or an array, not a ' + typeof script );
1289                                         }
1290                                         if ( !$.isPlainObject( style ) ) {
1291                                                 throw new Error( 'style must be an object, not a ' + typeof style );
1292                                         }
1293                                         if ( !$.isPlainObject( msgs ) ) {
1294                                                 throw new Error( 'msgs must be an object, not a ' + typeof msgs );
1295                                         }
1296                                         // Automatically register module
1297                                         if ( registry[module] === undefined ) {
1298                                                 mw.loader.register( module );
1299                                         }
1300                                         // Check for duplicate implementation
1301                                         if ( registry[module] !== undefined && registry[module].script !== undefined ) {
1302                                                 throw new Error( 'module already implemented: ' + module );
1303                                         }
1304                                         // Attach components
1305                                         registry[module].script = script;
1306                                         registry[module].style = style;
1307                                         registry[module].messages = msgs;
1308                                         // The module may already have been marked as erroneous
1309                                         if ( $.inArray( registry[module].state, ['error', 'missing'] ) === -1 ) {
1310                                                 registry[module].state = 'loaded';
1311                                                 if ( allReady( registry[module].dependencies ) ) {
1312                                                         execute( module );
1313                                                 }
1314                                         }
1315                                 },
1316
1317                                 /**
1318                                  * Executes a function as soon as one or more required modules are ready
1319                                  *
1320                                  * @param dependencies {String|Array} Module name or array of modules names the callback
1321                                  *  dependends on to be ready before executing
1322                                  * @param ready {Function} callback to execute when all dependencies are ready (optional)
1323                                  * @param error {Function} callback to execute when if dependencies have a errors (optional)
1324                                  */
1325                                 using: function ( dependencies, ready, error ) {
1326                                         var tod = typeof dependencies;
1327                                         // Validate input
1328                                         if ( tod !== 'object' && tod !== 'string' ) {
1329                                                 throw new Error( 'dependencies must be a string or an array, not a ' + tod );
1330                                         }
1331                                         // Allow calling with a single dependency as a string
1332                                         if ( tod === 'string' ) {
1333                                                 dependencies = [ dependencies ];
1334                                         }
1335                                         // Resolve entire dependency map
1336                                         dependencies = resolve( dependencies );
1337                                         if ( allReady( dependencies ) ) {
1338                                                 // Run ready immediately
1339                                                 if ( $.isFunction( ready ) ) {
1340                                                         ready();
1341                                                 }
1342                                         } else if ( filter( ['error', 'missing'], dependencies ).length ) {
1343                                                 // Execute error immediately if any dependencies have errors
1344                                                 if ( $.isFunction( error ) ) {
1345                                                         error( new Error( 'one or more dependencies have state "error" or "missing"' ),
1346                                                                 dependencies );
1347                                                 }
1348                                         } else {
1349                                                 // Not all dependencies are ready: queue up a request
1350                                                 request( dependencies, ready, error );
1351                                         }
1352                                 },
1353
1354                                 /**
1355                                  * Loads an external script or one or more modules for future use
1356                                  *
1357                                  * @param modules {mixed} Either the name of a module, array of modules,
1358                                  *  or a URL of an external script or style
1359                                  * @param type {String} mime-type to use if calling with a URL of an
1360                                  *  external script or style; acceptable values are "text/css" and
1361                                  *  "text/javascript"; if no type is provided, text/javascript is assumed.
1362                                  * @param async {Boolean} (optional) If true, load modules asynchronously
1363                                  *  even if document ready has not yet occurred. If false (default),
1364                                  *  block before document ready and load async after. If not set, true will
1365                                  *  be assumed if loading a URL, and false will be assumed otherwise.
1366                                  */
1367                                 load: function ( modules, type, async ) {
1368                                         var filtered, m, module, l;
1369
1370                                         // Validate input
1371                                         if ( typeof modules !== 'object' && typeof modules !== 'string' ) {
1372                                                 throw new Error( 'modules must be a string or an array, not a ' + typeof modules );
1373                                         }
1374                                         // Allow calling with an external url or single dependency as a string
1375                                         if ( typeof modules === 'string' ) {
1376                                                 // Support adding arbitrary external scripts
1377                                                 if ( /^(https?:)?\/\//.test( modules ) ) {
1378                                                         if ( async === undefined ) {
1379                                                                 // Assume async for bug 34542
1380                                                                 async = true;
1381                                                         }
1382                                                         if ( type === 'text/css' ) {
1383                                                                 // IE7-8 throws security warnings when inserting a <link> tag
1384                                                                 // with a protocol-relative URL set though attributes (instead of
1385                                                                 // properties) - when on HTTPS. See also bug #.
1386                                                                 l = document.createElement( 'link' );
1387                                                                 l.rel = 'stylesheet';
1388                                                                 l.href = modules;
1389                                                                 $( 'head' ).append( l );
1390                                                                 return;
1391                                                         }
1392                                                         if ( type === 'text/javascript' || type === undefined ) {
1393                                                                 addScript( modules, null, async );
1394                                                                 return;
1395                                                         }
1396                                                         // Unknown type
1397                                                         throw new Error( 'invalid type for external url, must be text/css or text/javascript. not ' + type );
1398                                                 }
1399                                                 // Called with single module
1400                                                 modules = [ modules ];
1401                                         }
1402
1403                                         // Filter out undefined modules, otherwise resolve() will throw
1404                                         // an exception for trying to load an undefined module.
1405                                         // Undefined modules are acceptable here in load(), because load() takes
1406                                         // an array of unrelated modules, whereas the modules passed to
1407                                         // using() are related and must all be loaded.
1408                                         for ( filtered = [], m = 0; m < modules.length; m += 1 ) {
1409                                                 module = registry[modules[m]];
1410                                                 if ( module !== undefined ) {
1411                                                         if ( $.inArray( module.state, ['error', 'missing'] ) === -1 ) {
1412                                                                 filtered[filtered.length] = modules[m];
1413                                                         }
1414                                                 }
1415                                         }
1416
1417                                         if ( filtered.length === 0 ) {
1418                                                 return;
1419                                         }
1420                                         // Resolve entire dependency map
1421                                         filtered = resolve( filtered );
1422                                         // If all modules are ready, nothing to be done
1423                                         if ( allReady( filtered ) ) {
1424                                                 return;
1425                                         }
1426                                         // If any modules have errors: also quit.
1427                                         if ( filter( ['error', 'missing'], filtered ).length ) {
1428                                                 return;
1429                                         }
1430                                         // Since some modules are not yet ready, queue up a request.
1431                                         request( filtered, null, null, async );
1432                                 },
1433
1434                                 /**
1435                                  * Changes the state of a module
1436                                  *
1437                                  * @param module {String|Object} module name or object of module name/state pairs
1438                                  * @param state {String} state name
1439                                  */
1440                                 state: function ( module, state ) {
1441                                         var m;
1442
1443                                         if ( typeof module === 'object' ) {
1444                                                 for ( m in module ) {
1445                                                         mw.loader.state( m, module[m] );
1446                                                 }
1447                                                 return;
1448                                         }
1449                                         if ( registry[module] === undefined ) {
1450                                                 mw.loader.register( module );
1451                                         }
1452                                         if ( $.inArray( state, ['ready', 'error', 'missing'] ) !== -1
1453                                                 && registry[module].state !== state ) {
1454                                                 // Make sure pending modules depending on this one get executed if their
1455                                                 // dependencies are now fulfilled!
1456                                                 registry[module].state = state;
1457                                                 handlePending( module );
1458                                         } else {
1459                                                 registry[module].state = state;
1460                                         }
1461                                 },
1462
1463                                 /**
1464                                  * Gets the version of a module
1465                                  *
1466                                  * @param module string name of module to get version for
1467                                  */
1468                                 getVersion: function ( module ) {
1469                                         if ( registry[module] !== undefined && registry[module].version !== undefined ) {
1470                                                 return formatVersionNumber( registry[module].version );
1471                                         }
1472                                         return null;
1473                                 },
1474
1475                                 /**
1476                                  * @deprecated since 1.18 use mw.loader.getVersion() instead
1477                                  */
1478                                 version: function () {
1479                                         return mw.loader.getVersion.apply( mw.loader, arguments );
1480                                 },
1481
1482                                 /**
1483                                  * Gets the state of a module
1484                                  *
1485                                  * @param module string name of module to get state for
1486                                  */
1487                                 getState: function ( module ) {
1488                                         if ( registry[module] !== undefined && registry[module].state !== undefined ) {
1489                                                 return registry[module].state;
1490                                         }
1491                                         return null;
1492                                 },
1493
1494                                 /**
1495                                  * Get names of all registered modules.
1496                                  *
1497                                  * @return {Array}
1498                                  */
1499                                 getModuleNames: function () {
1500                                         return $.map( registry, function ( i, key ) {
1501                                                 return key;
1502                                         } );
1503                                 },
1504
1505                                 /**
1506                                  * For backwards-compatibility with Squid-cached pages. Loads mw.user
1507                                  */
1508                                 go: function () {
1509                                         mw.loader.load( 'mediawiki.user' );
1510                                 }
1511                         };
1512                 }() ),
1513
1514                 /** HTML construction helper functions */
1515                 html: ( function () {
1516                         function escapeCallback( s ) {
1517                                 switch ( s ) {
1518                                         case '\'':
1519                                                 return '&#039;';
1520                                         case '"':
1521                                                 return '&quot;';
1522                                         case '<':
1523                                                 return '&lt;';
1524                                         case '>':
1525                                                 return '&gt;';
1526                                         case '&':
1527                                                 return '&amp;';
1528                                 }
1529                         }
1530
1531                         return {
1532                                 /**
1533                                  * Escape a string for HTML. Converts special characters to HTML entities.
1534                                  * @param s The string to escape
1535                                  */
1536                                 escape: function ( s ) {
1537                                         return s.replace( /['"<>&]/g, escapeCallback );
1538                                 },
1539
1540                                 /**
1541                                  * Wrapper object for raw HTML passed to mw.html.element().
1542                                  * @constructor
1543                                  */
1544                                 Raw: function ( value ) {
1545                                         this.value = value;
1546                                 },
1547
1548                                 /**
1549                                  * Wrapper object for CDATA element contents passed to mw.html.element()
1550                                  * @constructor
1551                                  */
1552                                 Cdata: function ( value ) {
1553                                         this.value = value;
1554                                 },
1555
1556                                 /**
1557                                  * Create an HTML element string, with safe escaping.
1558                                  *
1559                                  * @param name The tag name.
1560                                  * @param attrs An object with members mapping element names to values
1561                                  * @param contents The contents of the element. May be either:
1562                                  *  - string: The string is escaped.
1563                                  *  - null or undefined: The short closing form is used, e.g. <br/>.
1564                                  *  - this.Raw: The value attribute is included without escaping.
1565                                  *  - this.Cdata: The value attribute is included, and an exception is
1566                                  *   thrown if it contains an illegal ETAGO delimiter.
1567                                  *   See http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.3.2
1568                                  *
1569                                  * Example:
1570                                  *      var h = mw.html;
1571                                  *      return h.element( 'div', {},
1572                                  *              new h.Raw( h.element( 'img', {src: '<'} ) ) );
1573                                  * Returns <div><img src="&lt;"/></div>
1574                                  */
1575                                 element: function ( name, attrs, contents ) {
1576                                         var v, attrName, s = '<' + name;
1577
1578                                         for ( attrName in attrs ) {
1579                                                 v = attrs[attrName];
1580                                                 // Convert name=true, to name=name
1581                                                 if ( v === true ) {
1582                                                         v = attrName;
1583                                                 // Skip name=false
1584                                                 } else if ( v === false ) {
1585                                                         continue;
1586                                                 }
1587                                                 s += ' ' + attrName + '="' + this.escape( String( v ) ) + '"';
1588                                         }
1589                                         if ( contents === undefined || contents === null ) {
1590                                                 // Self close tag
1591                                                 s += '/>';
1592                                                 return s;
1593                                         }
1594                                         // Regular open tag
1595                                         s += '>';
1596                                         switch ( typeof contents ) {
1597                                                 case 'string':
1598                                                         // Escaped
1599                                                         s += this.escape( contents );
1600                                                         break;
1601                                                 case 'number':
1602                                                 case 'boolean':
1603                                                         // Convert to string
1604                                                         s += String( contents );
1605                                                         break;
1606                                                 default:
1607                                                         if ( contents instanceof this.Raw ) {
1608                                                                 // Raw HTML inclusion
1609                                                                 s += contents.value;
1610                                                         } else if ( contents instanceof this.Cdata ) {
1611                                                                 // CDATA
1612                                                                 if ( /<\/[a-zA-z]/.test( contents.value ) ) {
1613                                                                         throw new Error( 'mw.html.element: Illegal end tag found in CDATA' );
1614                                                                 }
1615                                                                 s += contents.value;
1616                                                         } else {
1617                                                                 throw new Error( 'mw.html.element: Invalid type of contents' );
1618                                                         }
1619                                         }
1620                                         s += '</' + name + '>';
1621                                         return s;
1622                                 }
1623                         };
1624                 }() ),
1625
1626                 // Skeleton user object. mediawiki.user.js extends this
1627                 user: {
1628                         options: new Map(),
1629                         tokens: new Map()
1630                 }
1631         };
1632
1633 }( jQuery ) );
1634
1635 // Alias $j to jQuery for backwards compatibility
1636 window.$j = jQuery;
1637
1638 // Attach to window and globally alias
1639 window.mw = window.mediaWiki = mw;
1640
1641 // Auto-register from pre-loaded startup scripts
1642 if ( jQuery.isFunction( window.startUp ) ) {
1643         window.startUp();
1644         window.startUp = undefined;
1645 }