resources/src/mediawiki/mediawiki.js

   1 /**
   2  * Base library for MediaWiki.
   3  *
   4  * Exposed globally as `mediaWiki` with `mw` as shortcut.
   5  *
   6  * @class mw
   7  * @alternateClassName mediaWiki
   8  * @singleton
   9  */
  10 /*jshint latedef:false */
  11 ( function ( $ ) {
  12         'use strict';
  13
  14         var mw, StringSet, log,
  15                 hasOwn = Object.prototype.hasOwnProperty,
  16                 slice = Array.prototype.slice,
  17                 trackCallbacks = $.Callbacks( 'memory' ),
  18                 trackHandlers = [],
  19                 trackQueue = [];
  20
  21         /**
  22          * FNV132 hash function
  23          *
  24          * This function implements the 32-bit version of FNV-1.
  25          * It is equivalent to hash( 'fnv132', ... ) in PHP, except
  26          * its output is base 36 rather than hex.
  27          * See <https://en.wikipedia.org/wiki/FNV_hash_function>
  28          *
  29          * @private
  30          * @param {string} str String to hash
  31          * @return {string} hash as an seven-character base 36 string
  32          */
  33         function fnv132( str ) {
  34                 /*jshint bitwise:false */
  35                 var hash = 0x811C9DC5,
  36                         i;
  37
  38                 for ( i = 0; i < str.length; i++ ) {
  39                         hash += ( hash << 1 ) + ( hash << 4 ) + ( hash << 7 ) + ( hash << 8 ) + ( hash << 24 );
  40                         hash ^= str.charCodeAt( i );
  41                 }
  42
  43                 hash = ( hash >>> 0 ).toString( 36 );
  44                 while ( hash.length < 7 ) {
  45                         hash = '0' + hash;
  46                 }
  47
  48                 return hash;
  49         }
  50
  51         StringSet = window.Set || ( function () {
  52                 /**
  53                  * @private
  54                  * @class
  55                  */
  56                 function StringSet() {
  57                         this.set = {};
  58                 }
  59                 StringSet.prototype.add = function ( value ) {
  60                         this.set[ value ] = true;
  61                 };
  62                 StringSet.prototype.has = function ( value ) {
  63                         return this.set.hasOwnProperty( value );
  64                 };
  65                 return StringSet;
  66         }() );
  67
  68         /**
  69          * Create an object that can be read from or written to from methods that allow
  70          * interaction both with single and multiple properties at once.
  71          *
  72          *     @example
  73          *
  74          *     var collection, query, results;
  75          *
  76          *     // Create your address book
  77          *     collection = new mw.Map();
  78          *
  79          *     // This data could be coming from an external source (eg. API/AJAX)
  80          *     collection.set( {
  81          *         'John Doe': 'john@example.org',
  82          *         'Jane Doe': 'jane@example.org',
  83          *         'George van Halen': 'gvanhalen@example.org'
  84          *     } );
  85          *
  86          *     wanted = ['John Doe', 'Jane Doe', 'Daniel Jackson'];
  87          *
  88          *     // You can detect missing keys first
  89          *     if ( !collection.exists( wanted ) ) {
  90          *         // One or more are missing (in this case: "Daniel Jackson")
  91          *         mw.log( 'One or more names were not found in your address book' );
  92          *     }
  93          *
  94          *     // Or just let it give you what it can. Optionally fill in from a default.
  95          *     results = collection.get( wanted, 'nobody@example.com' );
  96          *     mw.log( results['Jane Doe'] ); // "jane@example.org"
  97          *     mw.log( results['Daniel Jackson'] ); // "nobody@example.com"
  98          *
  99          * @class mw.Map
 100          *
 101          * @constructor
 102          * @param {Object|boolean} [values] The value-baring object to be mapped. Defaults to an
 103          *  empty object.
 104          *  For backwards-compatibility with mw.config, this can also be `true` in which case values
 105          *  are copied to the Window object as global variables (T72470). Values are copied in
 106          *  one direction only. Changes to globals are not reflected in the map.
 107          */
 108         function Map( values ) {
 109                 if ( values === true ) {
 110                         this.values = {};
 111
 112                         // Override #set to also set the global variable
 113                         this.set = function ( selection, value ) {
 114                                 var s;
 115
 116                                 if ( $.isPlainObject( selection ) ) {
 117                                         for ( s in selection ) {
 118                                                 setGlobalMapValue( this, s, selection[ s ] );
 119                                         }
 120                                         return true;
 121                                 }
 122                                 if ( typeof selection === 'string' && arguments.length ) {
 123                                         setGlobalMapValue( this, selection, value );
 124                                         return true;
 125                                 }
 126                                 return false;
 127                         };
 128
 129                         return;
 130                 }
 131
 132                 this.values = values || {};
 133         }
 134
 135         /**
 136          * Alias property to the global object.
 137          *
 138          * @private
 139          * @static
 140          * @param {mw.Map} map
 141          * @param {string} key
 142          * @param {Mixed} value
 143          */
 144         function setGlobalMapValue( map, key, value ) {
 145                 map.values[ key ] = value;
 146                 mw.log.deprecate(
 147                                 window,
 148                                 key,
 149                                 value,
 150                                 // Deprecation notice for mw.config globals (T58550, T72470)
 151                                 map === mw.config && 'Use mw.config instead.'
 152                 );
 153         }
 154
 155         Map.prototype = {
 156                 /**
 157                  * Get the value of one or more keys.
 158                  *
 159                  * If called with no arguments, all values are returned.
 160                  *
 161                  * @param {string|Array} [selection] Key or array of keys to retrieve values for.
 162                  * @param {Mixed} [fallback=null] Value for keys that don't exist.
 163                  * @return {Mixed|Object| null} If selection was a string, returns the value,
 164                  *  If selection was an array, returns an object of key/values.
 165                  *  If no selection is passed, the 'values' container is returned. (Beware that,
 166                  *  as is the default in JavaScript, the object is returned by reference.)
 167                  */
 168                 get: function ( selection, fallback ) {
 169                         var results, i;
 170                         // If we only do this in the `return` block, it'll fail for the
 171                         // call to get() from the mutli-selection block.
 172                         fallback = arguments.length > 1 ? fallback : null;
 173
 174                         if ( $.isArray( selection ) ) {
 175                                 selection = slice.call( selection );
 176                                 results = {};
 177                                 for ( i = 0; i < selection.length; i++ ) {
 178                                         results[ selection[ i ] ] = this.get( selection[ i ], fallback );
 179                                 }
 180                                 return results;
 181                         }
 182
 183                         if ( typeof selection === 'string' ) {
 184                                 if ( !hasOwn.call( this.values, selection ) ) {
 185                                         return fallback;
 186                                 }
 187                                 return this.values[ selection ];
 188                         }
 189
 190                         if ( selection === undefined ) {
 191                                 return this.values;
 192                         }
 193
 194                         // Invalid selection key
 195                         return null;
 196                 },
 197
 198                 /**
 199                  * Set one or more key/value pairs.
 200                  *
 201                  * @param {string|Object} selection Key to set value for, or object mapping keys to values
 202                  * @param {Mixed} [value] Value to set (optional, only in use when key is a string)
 203                  * @return {boolean} True on success, false on failure
 204                  */
 205                 set: function ( selection, value ) {
 206                         var s;
 207
 208                         if ( $.isPlainObject( selection ) ) {
 209                                 for ( s in selection ) {
 210                                         this.values[ s ] = selection[ s ];
 211                                 }
 212                                 return true;
 213                         }
 214                         if ( typeof selection === 'string' && arguments.length > 1 ) {
 215                                 this.values[ selection ] = value;
 216                                 return true;
 217                         }
 218                         return false;
 219                 },
 220
 221                 /**
 222                  * Check if one or more keys exist.
 223                  *
 224                  * @param {Mixed} selection Key or array of keys to check
 225                  * @return {boolean} True if the key(s) exist
 226                  */
 227                 exists: function ( selection ) {
 228                         var s;
 229
 230                         if ( $.isArray( selection ) ) {
 231                                 for ( s = 0; s < selection.length; s++ ) {
 232                                         if ( typeof selection[ s ] !== 'string' || !hasOwn.call( this.values, selection[ s ] ) ) {
 233                                                 return false;
 234                                         }
 235                                 }
 236                                 return true;
 237                         }
 238                         return typeof selection === 'string' && hasOwn.call( this.values, selection );
 239                 }
 240         };
 241
 242         /**
 243          * Object constructor for messages.
 244          *
 245          * Similar to the Message class in MediaWiki PHP.
 246          *
 247          * Format defaults to 'text'.
 248          *
 249          *     @example
 250          *
 251          *     var obj, str;
 252          *     mw.messages.set( {
 253          *         'hello': 'Hello world',
 254          *         'hello-user': 'Hello, $1!',
 255          *         'welcome-user': 'Welcome back to $2, $1! Last visit by $1: $3'
 256          *     } );
 257          *
 258          *     obj = new mw.Message( mw.messages, 'hello' );
 259          *     mw.log( obj.text() );
 260          *     // Hello world
 261          *
 262          *     obj = new mw.Message( mw.messages, 'hello-user', [ 'John Doe' ] );
 263          *     mw.log( obj.text() );
 264          *     // Hello, John Doe!
 265          *
 266          *     obj = new mw.Message( mw.messages, 'welcome-user', [ 'John Doe', 'Wikipedia', '2 hours ago' ] );
 267          *     mw.log( obj.text() );
 268          *     // Welcome back to Wikipedia, John Doe! Last visit by John Doe: 2 hours ago
 269          *
 270          *     // Using mw.message shortcut
 271          *     obj = mw.message( 'hello-user', 'John Doe' );
 272          *     mw.log( obj.text() );
 273          *     // Hello, John Doe!
 274          *
 275          *     // Using mw.msg shortcut
 276          *     str = mw.msg( 'hello-user', 'John Doe' );
 277          *     mw.log( str );
 278          *     // Hello, John Doe!
 279          *
 280          *     // Different formats
 281          *     obj = new mw.Message( mw.messages, 'hello-user', [ 'John "Wiki" <3 Doe' ] );
 282          *
 283          *     obj.format = 'text';
 284          *     str = obj.toString();
 285          *     // Same as:
 286          *     str = obj.text();
 287          *
 288          *     mw.log( str );
 289          *     // Hello, John "Wiki" <3 Doe!
 290          *
 291          *     mw.log( obj.escaped() );
 292          *     // Hello, John &quot;Wiki&quot; &lt;3 Doe!
 293          *
 294          * @class mw.Message
 295          *
 296          * @constructor
 297          * @param {mw.Map} map Message store
 298          * @param {string} key
 299          * @param {Array} [parameters]
 300          */
 301         function Message( map, key, parameters ) {
 302                 this.format = 'text';
 303                 this.map = map;
 304                 this.key = key;
 305                 this.parameters = parameters === undefined ? [] : slice.call( parameters );
 306                 return this;
 307         }
 308
 309         Message.prototype = {
 310                 /**
 311                  * Get parsed contents of the message.
 312                  *
 313                  * The default parser does simple $N replacements and nothing else.
 314                  * This may be overridden to provide a more complex message parser.
 315                  * The primary override is in the mediawiki.jqueryMsg module.
 316                  *
 317                  * This function will not be called for nonexistent messages.
 318                  *
 319                  * @return {string} Parsed message
 320                  */
 321                 parser: function () {
 322                         return mw.format.apply( null, [ this.map.get( this.key ) ].concat( this.parameters ) );
 323                 },
 324
 325                 /**
 326                  * Add (does not replace) parameters for `$N` placeholder values.
 327                  *
 328                  * @param {Array} parameters
 329                  * @chainable
 330                  */
 331                 params: function ( parameters ) {
 332                         var i;
 333                         for ( i = 0; i < parameters.length; i++ ) {
 334                                 this.parameters.push( parameters[ i ] );
 335                         }
 336                         return this;
 337                 },
 338
 339                 /**
 340                  * Convert message object to its string form based on current format.
 341                  *
 342                  * @return {string} Message as a string in the current form, or `<key>` if key
 343                  *  does not exist.
 344                  */
 345                 toString: function () {
 346                         var text;
 347
 348                         if ( !this.exists() ) {
 349                                 // Use <key> as text if key does not exist
 350                                 if ( this.format === 'escaped' || this.format === 'parse' ) {
 351                                         // format 'escaped' and 'parse' need to have the brackets and key html escaped
 352                                         return mw.html.escape( '<' + this.key + '>' );
 353                                 }
 354                                 return '<' + this.key + '>';
 355                         }
 356
 357                         if ( this.format === 'plain' || this.format === 'text' || this.format === 'parse' ) {
 358                                 text = this.parser();
 359                         }
 360
 361                         if ( this.format === 'escaped' ) {
 362                                 text = this.parser();
 363                                 text = mw.html.escape( text );
 364                         }
 365
 366                         return text;
 367                 },
 368
 369                 /**
 370                  * Change format to 'parse' and convert message to string
 371                  *
 372                  * If jqueryMsg is loaded, this parses the message text from wikitext
 373                  * (where supported) to HTML
 374                  *
 375                  * Otherwise, it is equivalent to plain.
 376                  *
 377                  * @return {string} String form of parsed message
 378                  */
 379                 parse: function () {
 380                         this.format = 'parse';
 381                         return this.toString();
 382                 },
 383
 384                 /**
 385                  * Change format to 'plain' and convert message to string
 386                  *
 387                  * This substitutes parameters, but otherwise does not change the
 388                  * message text.
 389                  *
 390                  * @return {string} String form of plain message
 391                  */
 392                 plain: function () {
 393                         this.format = 'plain';
 394                         return this.toString();
 395                 },
 396
 397                 /**
 398                  * Change format to 'text' and convert message to string
 399                  *
 400                  * If jqueryMsg is loaded, {{-transformation is done where supported
 401                  * (such as {{plural:}}, {{gender:}}, {{int:}}).
 402                  *
 403                  * Otherwise, it is equivalent to plain
 404                  *
 405                  * @return {string} String form of text message
 406                  */
 407                 text: function () {
 408                         this.format = 'text';
 409                         return this.toString();
 410                 },
 411
 412                 /**
 413                  * Change the format to 'escaped' and convert message to string
 414                  *
 415                  * This is equivalent to using the 'text' format (see #text), then
 416                  * HTML-escaping the output.
 417                  *
 418                  * @return {string} String form of html escaped message
 419                  */
 420                 escaped: function () {
 421                         this.format = 'escaped';
 422                         return this.toString();
 423                 },
 424
 425                 /**
 426                  * Check if a message exists
 427                  *
 428                  * @see mw.Map#exists
 429                  * @return {boolean}
 430                  */
 431                 exists: function () {
 432                         return this.map.exists( this.key );
 433                 }
 434         };
 435
 436         log = ( function () {
 437                 // Also update the restoration of methods in mediawiki.log.js
 438                 // when adding or removing methods here.
 439                 var log = function () {},
 440                         console = window.console;
 441
 442                 /**
 443                  * @class mw.log
 444                  * @singleton
 445                  */
 446
 447                 /**
 448                  * Write a message to the console's warning channel.
 449                  * Actions not supported by the browser console are silently ignored.
 450                  *
 451                  * @param {...string} msg Messages to output to console
 452                  */
 453                 log.warn = console && console.warn && Function.prototype.bind ?
 454                         Function.prototype.bind.call( console.warn, console ) :
 455                         $.noop;
 456
 457                 /**
 458                  * Write a message to the console's error channel.
 459                  *
 460                  * Most browsers provide a stacktrace by default if the argument
 461                  * is a caught Error object.
 462                  *
 463                  * @since 1.26
 464                  * @param {Error|...string} msg Messages to output to console
 465                  */
 466                 log.error = console && console.error && Function.prototype.bind ?
 467                         Function.prototype.bind.call( console.error, console ) :
 468                         $.noop;
 469
 470                 /**
 471                  * Create a property in a host object that, when accessed, will produce
 472                  * a deprecation warning in the console.
 473                  *
 474                  * @param {Object} obj Host object of deprecated property
 475                  * @param {string} key Name of property to create in `obj`
 476                  * @param {Mixed} val The value this property should return when accessed
 477                  * @param {string} [msg] Optional text to include in the deprecation message
 478                  */
 479                 log.deprecate = !Object.defineProperty ? function ( obj, key, val ) {
 480                         obj[ key ] = val;
 481                 } : function ( obj, key, val, msg ) {
 482                         msg = 'Use of "' + key + '" is deprecated.' + ( msg ? ( ' ' + msg ) : '' );
 483                         var logged = new StringSet();
 484                         function uniqueTrace() {
 485                                 var trace = new Error().stack;
 486                                 if ( logged.has( trace ) ) {
 487                                         return false;
 488                                 }
 489                                 logged.add( trace );
 490                                 return true;
 491                         }
 492                         Object.defineProperty( obj, key, {
 493                                 configurable: true,
 494                                 enumerable: true,
 495                                 get: function () {
 496                                         if ( uniqueTrace() ) {
 497                                                 mw.track( 'mw.deprecate', key );
 498                                                 mw.log.warn( msg );
 499                                         }
 500                                         return val;
 501                                 },
 502                                 set: function ( newVal ) {
 503                                         if ( uniqueTrace() ) {
 504                                                 mw.track( 'mw.deprecate', key );
 505                                                 mw.log.warn( msg );
 506                                         }
 507                                         val = newVal;
 508                                 }
 509                         } );
 510
 511                 };
 512
 513                 return log;
 514         }() );
 515
 516         /**
 517          * @class mw
 518          */
 519         mw = {
 520
 521                 /**
 522                  * Get the current time, measured in milliseconds since January 1, 1970 (UTC).
 523                  *
 524                  * On browsers that implement the Navigation Timing API, this function will produce floating-point
 525                  * values with microsecond precision that are guaranteed to be monotonic. On all other browsers,
 526                  * it will fall back to using `Date`.
 527                  *
 528                  * @return {number} Current time
 529                  */
 530                 now: ( function () {
 531                         var perf = window.performance,
 532                                 navStart = perf && perf.timing && perf.timing.navigationStart;
 533                         return navStart && typeof perf.now === 'function' ?
 534                                 function () { return navStart + perf.now(); } :
 535                                 function () { return +new Date(); };
 536                 }() ),
 537
 538                 /**
 539                  * Format a string. Replace $1, $2 ... $N with positional arguments.
 540                  *
 541                  * Used by Message#parser().
 542                  *
 543                  * @since 1.25
 544                  * @param {string} formatString Format string
 545                  * @param {...Mixed} parameters Values for $N replacements
 546                  * @return {string} Formatted string
 547                  */
 548                 format: function ( formatString ) {
 549                         var parameters = slice.call( arguments, 1 );
 550                         return formatString.replace( /\$(\d+)/g, function ( str, match ) {
 551                                 var index = parseInt( match, 10 ) - 1;
 552                                 return parameters[ index ] !== undefined ? parameters[ index ] : '$' + match;
 553                         } );
 554                 },
 555
 556                 /**
 557                  * Track an analytic event.
 558                  *
 559                  * This method provides a generic means for MediaWiki JavaScript code to capture state
 560                  * information for analysis. Each logged event specifies a string topic name that describes
 561                  * the kind of event that it is. Topic names consist of dot-separated path components,
 562                  * arranged from most general to most specific. Each path component should have a clear and
 563                  * well-defined purpose.
 564                  *
 565                  * Data handlers are registered via `mw.trackSubscribe`, and receive the full set of
 566                  * events that match their subcription, including those that fired before the handler was
 567                  * bound.
 568                  *
 569                  * @param {string} topic Topic name
 570                  * @param {Object} [data] Data describing the event, encoded as an object
 571                  */
 572                 track: function ( topic, data ) {
 573                         trackQueue.push( { topic: topic, timeStamp: mw.now(), data: data } );
 574                         trackCallbacks.fire( trackQueue );
 575                 },
 576
 577                 /**
 578                  * Register a handler for subset of analytic events, specified by topic.
 579                  *
 580                  * Handlers will be called once for each tracked event, including any events that fired before the
 581                  * handler was registered; 'this' is set to a plain object with a 'timeStamp' property indicating
 582                  * the exact time at which the event fired, a string 'topic' property naming the event, and a
 583                  * 'data' property which is an object of event-specific data. The event topic and event data are
 584                  * also passed to the callback as the first and second arguments, respectively.
 585                  *
 586                  * @param {string} topic Handle events whose name starts with this string prefix
 587                  * @param {Function} callback Handler to call for each matching tracked event
 588                  * @param {string} callback.topic
 589                  * @param {Object} [callback.data]
 590                  */
 591                 trackSubscribe: function ( topic, callback ) {
 592                         var seen = 0;
 593                         function handler( trackQueue ) {
 594                                 var event;
 595                                 for ( ; seen < trackQueue.length; seen++ ) {
 596                                         event = trackQueue[ seen ];
 597                                         if ( event.topic.indexOf( topic ) === 0 ) {
 598                                                 callback.call( event, event.topic, event.data );
 599                                         }
 600                                 }
 601                         }
 602
 603                         trackHandlers.push( [ handler, callback ] );
 604
 605                         trackCallbacks.add( handler );
 606                 },
 607
 608                 /**
 609                  * Stop handling events for a particular handler
 610                  *
 611                  * @param {Function} callback
 612                  */
 613                 trackUnsubscribe: function ( callback ) {
 614                         trackHandlers = $.grep( trackHandlers, function ( fns ) {
 615                                 if ( fns[ 1 ] === callback ) {
 616                                         trackCallbacks.remove( fns[ 0 ] );
 617                                         // Ensure the tuple is removed to avoid holding on to closures
 618                                         return false;
 619                                 }
 620                                 return true;
 621                         } );
 622                 },
 623
 624                 // Expose Map constructor
 625                 Map: Map,
 626
 627                 // Expose Message constructor
 628                 Message: Message,
 629
 630                 /**
 631                  * Map of configuration values.
 632                  *
 633                  * Check out [the complete list of configuration values](https://www.mediawiki.org/wiki/Manual:Interface/JavaScript#mw.config)
 634                  * on mediawiki.org.
 635                  *
 636                  * If `$wgLegacyJavaScriptGlobals` is true, this Map will add its values to the
 637                  * global `window` object.
 638                  *
 639                  * @property {mw.Map} config
 640                  */
 641                 // Dummy placeholder later assigned in ResourceLoaderStartUpModule
 642                 config: null,
 643
 644                 /**
 645                  * Empty object for third-party libraries, for cases where you don't
 646                  * want to add a new global, or the global is bad and needs containment
 647                  * or wrapping.
 648                  *
 649                  * @property
 650                  */
 651                 libs: {},
 652
 653                 /**
 654                  * Access container for deprecated functionality that can be moved from
 655                  * from their legacy location and attached to this object (e.g. a global
 656                  * function that is deprecated and as stop-gap can be exposed through here).
 657                  *
 658                  * This was reserved for future use but never ended up being used.
 659                  *
 660                  * @deprecated since 1.22 Let deprecated identifiers keep their original name
 661                  *  and use mw.log#deprecate to create an access container for tracking.
 662                  * @property
 663                  */
 664                 legacy: {},
 665
 666                 /**
 667                  * Store for messages.
 668                  *
 669                  * @property {mw.Map}
 670                  */
 671                 messages: new Map(),
 672
 673                 /**
 674                  * Store for templates associated with a module.
 675                  *
 676                  * @property {mw.Map}
 677                  */
 678                 templates: new Map(),
 679
 680                 /**
 681                  * Get a message object.
 682                  *
 683                  * Shortcut for `new mw.Message( mw.messages, key, parameters )`.
 684                  *
 685                  * @see mw.Message
 686                  * @param {string} key Key of message to get
 687                  * @param {...Mixed} parameters Values for $N replacements
 688                  * @return {mw.Message}
 689                  */
 690                 message: function ( key ) {
 691                         var parameters = slice.call( arguments, 1 );
 692                         return new Message( mw.messages, key, parameters );
 693                 },
 694
 695                 /**
 696                  * Get a message string using the (default) 'text' format.
 697                  *
 698                  * Shortcut for `mw.message( key, parameters... ).text()`.
 699                  *
 700                  * @see mw.Message
 701                  * @param {string} key Key of message to get
 702                  * @param {...Mixed} parameters Values for $N replacements
 703                  * @return {string}
 704                  */
 705                 msg: function () {
 706                         return mw.message.apply( mw.message, arguments ).toString();
 707                 },
 708
 709                 /**
 710                  * No-op dummy placeholder for {@link mw.log} in debug mode.
 711                  *
 712                  * @method
 713                  */
 714                 log: log,
 715
 716                 /**
 717                  * Client for ResourceLoader server end point.
 718                  *
 719                  * This client is in charge of maintaining the module registry and state
 720                  * machine, initiating network (batch) requests for loading modules, as
 721                  * well as dependency resolution and execution of source code.
 722                  *
 723                  * For more information, refer to
 724                  * <https://www.mediawiki.org/wiki/ResourceLoader/Features>
 725                  *
 726                  * @class mw.loader
 727                  * @singleton
 728                  */
 729                 loader: ( function () {
 730
 731                         /**
 732                          * Fired via mw.track on various resource loading errors.
 733                          *
 734                          * @event resourceloader_exception
 735                          * @param {Error|Mixed} e The error that was thrown. Almost always an Error
 736                          *   object, but in theory module code could manually throw something else, and that
 737                          *   might also end up here.
 738                          * @param {string} [module] Name of the module which caused the error. Omitted if the
 739                          *   error is not module-related or the module cannot be easily identified due to
 740                          *   batched handling.
 741                          * @param {string} source Source of the error. Possible values:
 742                          *
 743                          *   - style: stylesheet error (only affects old IE where a special style loading method
 744                          *     is used)
 745                          *   - load-callback: exception thrown by user callback
 746                          *   - module-execute: exception thrown by module code
 747                          *   - store-eval: could not evaluate module code cached in localStorage
 748                          *   - store-localstorage-init: localStorage or JSON parse error in mw.loader.store.init
 749                          *   - store-localstorage-json: JSON conversion error in mw.loader.store.set
 750                          *   - store-localstorage-update: localStorage or JSON conversion error in mw.loader.store.update
 751                          */
 752
 753                         /**
 754                          * Fired via mw.track on resource loading error conditions.
 755                          *
 756                          * @event resourceloader_assert
 757                          * @param {string} source Source of the error. Possible values:
 758                          *
 759                          *   - bug-T59567: failed to cache script due to an Opera function -> string conversion
 760                          *     bug; see <https://phabricator.wikimedia.org/T59567> for details
 761                          */
 762
 763                         /**
 764                          * Mapping of registered modules.
 765                          *
 766                          * See #implement and #execute for exact details on support for script, style and messages.
 767                          *
 768                          * Format:
 769                          *
 770                          *     {
 771                          *         'moduleName': {
 772                          *             // From mw.loader.register()
 773                          *             'version': '########' (hash)
 774                          *             'dependencies': ['required.foo', 'bar.also', ...], (or) function () {}
 775                          *             'group': 'somegroup', (or) null
 776                          *             'source': 'local', (or) 'anotherwiki'
 777                          *             'skip': 'return !!window.Example', (or) null
 778                          *             'module': export Object
 779                          *
 780                          *             // Set from execute() or mw.loader.state()
 781                          *             'state': 'registered', 'loaded', 'loading', 'ready', 'error', or 'missing'
 782                          *
 783                          *             // Optionally added at run-time by mw.loader.implement()
 784                          *             'skipped': true
 785                          *             'script': closure, array of urls, or string
 786                          *             'style': { ... } (see #execute)
 787                          *             'messages': { 'key': 'value', ... }
 788                          *         }
 789                          *     }
 790                          *
 791                          * State machine:
 792                          *
 793                          * - `registered`:
 794                          *    The module is known to the system but not yet required.
 795                          *    Meta data is registered via mw.loader#register. Calls to that method are
 796                          *    generated server-side by the startup module.
 797                          * - `loading`:
 798                          *    The module was required through mw.loader (either directly or as dependency of
 799                          *    another module). The client will fetch module contents from the server.
 800                          *    The contents are then stashed in the registry via mw.loader#implement.
 801                          * - `loaded`:
 802                          *    The module has been loaded from the server and stashed via mw.loader#implement.
 803                          *    If the module has no more dependencies in-flight, the module will be executed
 804                          *    immediately. Otherwise execution is deferred, controlled via #handlePending.
 805                          * - `executing`:
 806                          *    The module is being executed.
 807                          * - `ready`:
 808                          *    The module has been successfully executed.
 809                          * - `error`:
 810                          *    The module (or one of its dependencies) produced an error during execution.
 811                          * - `missing`:
 812                          *    The module was registered client-side and requested, but the server denied knowledge
 813                          *    of the module's existence.
 814                          *
 815                          * @property
 816                          * @private
 817                          */
 818                         var registry = {},
 819                                 // Mapping of sources, keyed by source-id, values are strings.
 820                                 //
 821                                 // Format:
 822                                 //
 823                                 //     {
 824                                 //         'sourceId': 'http://example.org/w/load.php'
 825                                 //     }
 826                                 //
 827                                 sources = {},
 828
 829                                 // For queueModuleScript()
 830                                 handlingPendingRequests = false,
 831                                 pendingRequests = [],
 832
 833                                 // List of modules to be loaded
 834                                 queue = [],
 835
 836                                 /**
 837                                  * List of callback jobs waiting for modules to be ready.
 838                                  *
 839                                  * Jobs are created by #enqueue() and run by #handlePending().
 840                                  *
 841                                  * Typically when a job is created for a module, the job's dependencies contain
 842                                  * both the required module and all its recursive dependencies.
 843                                  *
 844                                  * Format:
 845                                  *
 846                                  *     {
 847                                  *         'dependencies': [ module names ],
 848                                  *         'ready': Function callback
 849                                  *         'error': Function callback
 850                                  *     }
 851                                  *
 852                                  * @property {Object[]} jobs
 853                                  * @private
 854                                  */
 855                                 jobs = [],
 856
 857                                 // For getMarker()
 858                                 marker = null,
 859
 860                                 // For addEmbeddedCSS()
 861                                 cssBuffer = '',
 862                                 cssBufferTimer = null,
 863                                 cssCallbacks = $.Callbacks(),
 864                                 isIE9 = document.documentMode === 9,
 865                                 rAF = window.requestAnimationFrame || setTimeout;
 866
 867                         function getMarker() {
 868                                 if ( !marker ) {
 869                                         // Cache
 870                                         marker = document.querySelector( 'meta[name="ResourceLoaderDynamicStyles"]' );
 871                                         if ( !marker ) {
 872                                                 mw.log( 'Create <meta name="ResourceLoaderDynamicStyles"> dynamically' );
 873                                                 marker = $( '<meta>' ).attr( 'name', 'ResourceLoaderDynamicStyles' ).appendTo( 'head' )[ 0 ];
 874                                         }
 875                                 }
 876                                 return marker;
 877                         }
 878
 879                         /**
 880                          * Create a new style element and add it to the DOM.
 881                          *
 882                          * @private
 883                          * @param {string} text CSS text
 884                          * @param {Node} [nextNode] The element where the style tag
 885                          *  should be inserted before
 886                          * @return {HTMLElement} Reference to the created style element
 887                          */
 888                         function newStyleTag( text, nextNode ) {
 889                                 var s = document.createElement( 'style' );
 890
 891                                 s.appendChild( document.createTextNode( text ) );
 892                                 if ( nextNode && nextNode.parentNode ) {
 893                                         nextNode.parentNode.insertBefore( s, nextNode );
 894                                 } else {
 895                                         document.getElementsByTagName( 'head' )[ 0 ].appendChild( s );
 896                                 }
 897
 898                                 return s;
 899                         }
 900
 901                         /**
 902                          * Add a bit of CSS text to the current browser page.
 903                          *
 904                          * The CSS will be appended to an existing ResourceLoader-created `<style>` tag
 905                          * or create a new one based on whether the given `cssText` is safe for extension.
 906                          *
 907                          * @private
 908                          * @param {string} [cssText=cssBuffer] If called without cssText,
 909                          *  the internal buffer will be inserted instead.
 910                          * @param {Function} [callback]
 911                          */
 912                         function addEmbeddedCSS( cssText, callback ) {
 913                                 var $style, styleEl;
 914
 915                                 function fireCallbacks() {
 916                                         var oldCallbacks = cssCallbacks;
 917                                         // Reset cssCallbacks variable so it's not polluted by any calls to
 918                                         // addEmbeddedCSS() from one of the callbacks (T105973)
 919                                         cssCallbacks = $.Callbacks();
 920                                         oldCallbacks.fire().empty();
 921                                 }
 922
 923                                 if ( callback ) {
 924                                         cssCallbacks.add( callback );
 925                                 }
 926
 927                                 // Yield once before creating the <style> tag. This lets multiple stylesheets
 928                                 // accumulate into one buffer, allowing us to reduce how often new stylesheets
 929                                 // are inserted in the browser. Appending a stylesheet and waiting for the
 930                                 // browser to repaint is fairly expensive. (T47810)
 931                                 if ( cssText ) {
 932                                         // Don't extend the buffer if the item needs its own stylesheet.
 933                                         // Keywords like `@import` are only valid at the start of a stylesheet (T37562).
 934                                         if ( !cssBuffer || cssText.slice( 0, '@import'.length ) !== '@import' ) {
 935                                                 // Linebreak for somewhat distinguishable sections
 936                                                 cssBuffer += '\n' + cssText;
 937                                                 if ( !cssBufferTimer ) {
 938                                                         cssBufferTimer = rAF( function () {
 939                                                                 // Wrap in anonymous function that takes no arguments
 940                                                                 // Support: Firefox < 13
 941                                                                 // Firefox 12 has non-standard behaviour of passing a number
 942                                                                 // as first argument to a setTimeout callback.
 943                                                                 // http://benalman.com/news/2009/07/the-mysterious-firefox-settime/
 944                                                                 addEmbeddedCSS();
 945                                                         } );
 946                                                 }
 947                                                 return;
 948                                         }
 949
 950                                 // This is a scheduled flush for the buffer
 951                                 } else {
 952                                         cssBufferTimer = null;
 953                                         cssText = cssBuffer;
 954                                         cssBuffer = '';
 955                                 }
 956
 957                                 // By default, always create a new <style>. Appending text to a <style> tag is
 958                                 // is a performance anti-pattern as it requires CSS to be reparsed (T47810).
 959                                 //
 960                                 // Support: IE 6-9
 961                                 // Try to re-use existing <style> tags due to the IE stylesheet limit (T33676).
 962                                 if ( isIE9 ) {
 963                                         $style = $( getMarker() ).prev();
 964                                         // Verify that the element before the marker actually is a <style> tag created
 965                                         // by mw.loader (not some other style tag, or e.g. a <meta> tag).
 966                                         if ( $style.data( 'ResourceLoaderDynamicStyleTag' ) ) {
 967                                                 styleEl = $style[ 0 ];
 968                                                 styleEl.appendChild( document.createTextNode( cssText ) );
 969                                                 fireCallbacks();
 970                                                 return;
 971                                         }
 972                                         // Else: No existing tag to reuse. Continue below and create the first one.
 973                                 }
 974
 975                                 $style = $( newStyleTag( cssText, getMarker() ) );
 976
 977                                 if ( isIE9 ) {
 978                                         $style.data( 'ResourceLoaderDynamicStyleTag', true );
 979                                 }
 980
 981                                 fireCallbacks();
 982                         }
 983
 984                         /**
 985                          * @private
 986                          * @param {Array} modules List of module names
 987                          * @return {string} Hash of concatenated version hashes.
 988                          */
 989                         function getCombinedVersion( modules ) {
 990                                 var hashes = $.map( modules, function ( module ) {
 991                                         return registry[ module ].version;
 992                                 } );
 993                                 return fnv132( hashes.join( '' ) );
 994                         }
 995
 996                         /**
 997                          * Determine whether all dependencies are in state 'ready', which means we may
 998                          * execute the module or job now.
 999                          *
1000                          * @private
1001                          * @param {Array} modules Names of modules to be checked
1002                          * @return {boolean} True if all modules are in state 'ready', false otherwise
1003                          */
1004                         function allReady( modules ) {
1005                                 var i;
1006                                 for ( i = 0; i < modules.length; i++ ) {
1007                                         if ( mw.loader.getState( modules[ i ] ) !== 'ready' ) {
1008                                                 return false;
1009                                         }
1010                                 }
1011                                 return true;
1012                         }
1013
1014                         /**
1015                          * Determine whether all dependencies are in state 'ready', which means we may
1016                          * execute the module or job now.
1017                          *
1018                          * @private
1019                          * @param {Array} modules Names of modules to be checked
1020                          * @return {boolean} True if no modules are in state 'error' or 'missing', false otherwise
1021                          */
1022                         function anyFailed( modules ) {
1023                                 var i, state;
1024                                 for ( i = 0; i < modules.length; i++ ) {
1025                                         state = mw.loader.getState( modules[ i ] );
1026                                         if ( state === 'error' || state === 'missing' ) {
1027                                                 return true;
1028                                         }
1029                                 }
1030                                 return false;
1031                         }
1032
1033                         /**
1034                          * A module has entered state 'ready', 'error', or 'missing'. Automatically update
1035                          * pending jobs and modules that depend upon this module. If the given module failed,
1036                          * propagate the 'error' state up the dependency tree. Otherwise, go ahead and execute
1037                          * all jobs/modules now having their dependencies satisfied.
1038                          *
1039                          * Jobs that depend on a failed module, will have their error callback ran (if any).
1040                          *
1041                          * @private
1042                          * @param {string} module Name of module that entered one of the states 'ready', 'error', or 'missing'.
1043                          */
1044                         function handlePending( module ) {
1045                                 var j, job, hasErrors, m, stateChange;
1046
1047                                 if ( registry[ module ].state === 'error' || registry[ module ].state === 'missing' ) {
1048                                         // If the current module failed, mark all dependent modules also as failed.
1049                                         // Iterate until steady-state to propagate the error state upwards in the
1050                                         // dependency tree.
1051                                         do {
1052                                                 stateChange = false;
1053                                                 for ( m in registry ) {
1054                                                         if ( registry[ m ].state !== 'error' && registry[ m ].state !== 'missing' ) {
1055                                                                 if ( anyFailed( registry[ m ].dependencies ) ) {
1056                                                                         registry[ m ].state = 'error';
1057                                                                         stateChange = true;
1058                                                                 }
1059                                                         }
1060                                                 }
1061                                         } while ( stateChange );
1062                                 }
1063
1064                                 // Execute all jobs whose dependencies are either all satisfied or contain at least one failed module.
1065                                 for ( j = 0; j < jobs.length; j++ ) {
1066                                         hasErrors = anyFailed( jobs[ j ].dependencies );
1067                                         if ( hasErrors || allReady( jobs[ j ].dependencies ) ) {
1068                                                 // All dependencies satisfied, or some have errors
1069                                                 job = jobs[ j ];
1070                                                 jobs.splice( j, 1 );
1071                                                 j -= 1;
1072                                                 try {
1073                                                         if ( hasErrors ) {
1074                                                                 if ( typeof job.error === 'function' ) {
1075                                                                         job.error( new Error( 'Module ' + module + ' has failed dependencies' ), [ module ] );
1076                                                                 }
1077                                                         } else {
1078                                                                 if ( typeof job.ready === 'function' ) {
1079                                                                         job.ready();
1080                                                                 }
1081                                                         }
1082                                                 } catch ( e ) {
1083                                                         // A user-defined callback raised an exception.
1084                                                         // Swallow it to protect our state machine!
1085                                                         mw.track( 'resourceloader.exception', { exception: e, module: module, source: 'load-callback' } );
1086                                                 }
1087                                         }
1088                                 }
1089
1090                                 if ( registry[ module ].state === 'ready' ) {
1091                                         // The current module became 'ready'. Set it in the module store, and recursively execute all
1092                                         // dependent modules that are loaded and now have all dependencies satisfied.
1093                                         mw.loader.store.set( module, registry[ module ] );
1094                                         for ( m in registry ) {
1095                                                 if ( registry[ m ].state === 'loaded' && allReady( registry[ m ].dependencies ) ) {
1096                                                         execute( m );
1097                                                 }
1098                                         }
1099                                 }
1100                         }
1101
1102                         /**
1103                          * Resolve dependencies and detect circular references.
1104                          *
1105                          * @private
1106                          * @param {string} module Name of the top-level module whose dependencies shall be
1107                          *  resolved and sorted.
1108                          * @param {Array} resolved Returns a topological sort of the given module and its
1109                          *  dependencies, such that later modules depend on earlier modules. The array
1110                          *  contains the module names. If the array contains already some module names,
1111                          *  this function appends its result to the pre-existing array.
1112                          * @param {StringSet} [unresolved] Used to track the current dependency
1113                          *  chain, and to report loops in the dependency graph.
1114                          * @throws {Error} If any unregistered module or a dependency loop is encountered
1115                          */
1116                         function sortDependencies( module, resolved, unresolved ) {
1117                                 var i, deps, skip;
1118
1119                                 if ( !hasOwn.call( registry, module ) ) {
1120                                         throw new Error( 'Unknown dependency: ' + module );
1121                                 }
1122
1123                                 if ( registry[ module ].skip !== null ) {
1124                                         /*jshint evil:true */
1125                                         skip = new Function( registry[ module ].skip );
1126                                         registry[ module ].skip = null;
1127                                         if ( skip() ) {
1128                                                 registry[ module ].skipped = true;
1129                                                 registry[ module ].dependencies = [];
1130                                                 registry[ module ].state = 'ready';
1131                                                 handlePending( module );
1132                                                 return;
1133                                         }
1134                                 }
1135
1136                                 // Resolves dynamic loader function and replaces it with its own results
1137                                 if ( typeof registry[ module ].dependencies === 'function' ) {
1138                                         registry[ module ].dependencies = registry[ module ].dependencies();
1139                                         // Ensures the module's dependencies are always in an array
1140                                         if ( typeof registry[ module ].dependencies !== 'object' ) {
1141                                                 registry[ module ].dependencies = [ registry[ module ].dependencies ];
1142                                         }
1143                                 }
1144                                 if ( $.inArray( module, resolved ) !== -1 ) {
1145                                         // Module already resolved; nothing to do
1146                                         return;
1147                                 }
1148                                 // Create unresolved if not passed in
1149                                 if ( !unresolved ) {
1150                                         unresolved = new StringSet();
1151                                 }
1152                                 // Tracks down dependencies
1153                                 deps = registry[ module ].dependencies;
1154                                 for ( i = 0; i < deps.length; i++ ) {
1155                                         if ( $.inArray( deps[ i ], resolved ) === -1 ) {
1156                                                 if ( unresolved.has( deps[ i ] ) ) {
1157                                                         throw new Error( mw.format(
1158                                                                 'Circular reference detected: $1 -> $2',
1159                                                                 module,
1160                                                                 deps[ i ]
1161                                                         ) );
1162                                                 }
1163
1164                                                 unresolved.add(  module );
1165                                                 sortDependencies( deps[ i ], resolved, unresolved );
1166                                         }
1167                                 }
1168                                 resolved.push( module );
1169                         }
1170
1171                         /**
1172                          * Get names of module that a module depends on, in their proper dependency order.
1173                          *
1174                          * @private
1175                          * @param {string[]} modules Array of string module names
1176                          * @return {Array} List of dependencies, including 'module'.
1177                          */
1178                         function resolve( modules ) {
1179                                 var resolved = [];
1180                                 $.each( modules, function ( idx, module ) {
1181                                         sortDependencies( module, resolved );
1182                                 } );
1183                                 return resolved;
1184                         }
1185
1186                         /**
1187                          * Load and execute a script.
1188                          *
1189                          * @private
1190                          * @param {string} src URL to script, will be used as the src attribute in the script tag
1191                          * @return {jQuery.Promise}
1192                          */
1193                         function addScript( src ) {
1194                                 return $.ajax( {
1195                                         url: src,
1196                                         dataType: 'script',
1197                                         // Force jQuery behaviour to be for crossDomain. Otherwise jQuery would use
1198                                         // XHR for a same domain request instead of <script>, which changes the request
1199                                         // headers (potentially missing a cache hit), and reduces caching in general
1200                                         // since browsers cache XHR much less (if at all). And XHR means we retrieve
1201                                         // text, so we'd need to $.globalEval, which then messes up line numbers.
1202                                         crossDomain: true,
1203                                         cache: true
1204                                 } );
1205                         }
1206
1207                         /**
1208                          * Queue the loading and execution of a script for a particular module.
1209                          *
1210                          * @private
1211                          * @param {string} src URL of the script
1212                          * @param {string} [moduleName] Name of currently executing module
1213                          * @return {jQuery.Promise}
1214                          */
1215                         function queueModuleScript( src, moduleName ) {
1216                                 var r = $.Deferred();
1217
1218                                 pendingRequests.push( function () {
1219                                         if ( moduleName && hasOwn.call( registry, moduleName ) ) {
1220                                                 // Emulate runScript() part of execute()
1221                                                 window.require = mw.loader.require;
1222                                                 window.module = registry[ moduleName ].module;
1223                                         }
1224                                         addScript( src ).always( function () {
1225                                                 // 'module.exports' should not persist after the file is executed to
1226                                                 // avoid leakage to unrelated code. 'require' should be kept, however,
1227                                                 // as asynchronous access to 'require' is allowed and expected. (T144879)
1228                                                 delete window.module;
1229                                                 r.resolve();
1230
1231                                                 // Start the next one (if any)
1232                                                 if ( pendingRequests[ 0 ] ) {
1233                                                         pendingRequests.shift()();
1234                                                 } else {
1235                                                         handlingPendingRequests = false;
1236                                                 }
1237                                         } );
1238                                 } );
1239                                 if ( !handlingPendingRequests && pendingRequests[ 0 ] ) {
1240                                         handlingPendingRequests = true;
1241                                         pendingRequests.shift()();
1242                                 }
1243                                 return r.promise();
1244                         }
1245
1246                         /**
1247                          * Utility function for execute()
1248                          *
1249                          * @ignore
1250                          */
1251                         function addLink( media, url ) {
1252                                 var el = document.createElement( 'link' );
1253
1254                                 el.rel = 'stylesheet';
1255                                 if ( media && media !== 'all' ) {
1256                                         el.media = media;
1257                                 }
1258                                 // If you end up here from an IE exception "SCRIPT: Invalid property value.",
1259                                 // see #addEmbeddedCSS, bug 31676, and bug 47277 for details.
1260                                 el.href = url;
1261
1262                                 $( getMarker() ).before( el );
1263                         }
1264
1265                         /**
1266                          * Executes a loaded module, making it ready to use
1267                          *
1268                          * @private
1269                          * @param {string} module Module name to execute
1270                          */
1271                         function execute( module ) {
1272                                 var key, value, media, i, urls, cssHandle, checkCssHandles, runScript,
1273                                         cssHandlesRegistered = false;
1274
1275                                 if ( !hasOwn.call( registry, module ) ) {
1276                                         throw new Error( 'Module has not been registered yet: ' + module );
1277                                 }
1278                                 if ( registry[ module ].state !== 'loaded' ) {
1279                                         throw new Error( 'Module in state "' + registry[ module ].state + '" may not be executed: ' + module );
1280                                 }
1281
1282                                 registry[ module ].state = 'executing';
1283
1284                                 runScript = function () {
1285                                         var script, markModuleReady, nestedAddScript, legacyWait, implicitDependencies,
1286                                                 // Expand to include dependencies since we have to exclude both legacy modules
1287                                                 // and their dependencies from the legacyWait (to prevent a circular dependency).
1288                                                 legacyModules = resolve( mw.config.get( 'wgResourceLoaderLegacyModules', [] ) );
1289
1290                                         script = registry[ module ].script;
1291                                         markModuleReady = function () {
1292                                                 registry[ module ].state = 'ready';
1293                                                 handlePending( module );
1294                                         };
1295                                         nestedAddScript = function ( arr, callback, i ) {
1296                                                 // Recursively call queueModuleScript() in its own callback
1297                                                 // for each element of arr.
1298                                                 if ( i >= arr.length ) {
1299                                                         // We're at the end of the array
1300                                                         callback();
1301                                                         return;
1302                                                 }
1303
1304                                                 queueModuleScript( arr[ i ], module ).always( function () {
1305                                                         nestedAddScript( arr, callback, i + 1 );
1306                                                 } );
1307                                         };
1308
1309                                         implicitDependencies = ( $.inArray( module, legacyModules ) !== -1 )
1310                                                 ? []
1311                                                 : legacyModules;
1312
1313                                         if ( module === 'user' ) {
1314                                                 // Implicit dependency on the site module. Not real dependency because
1315                                                 // it should run after 'site' regardless of whether it succeeds or fails.
1316                                                 implicitDependencies.push( 'site' );
1317                                         }
1318
1319                                         legacyWait = implicitDependencies.length
1320                                                 ? mw.loader.using( implicitDependencies )
1321                                                 : $.Deferred().resolve();
1322
1323                                         legacyWait.always( function () {
1324                                                 try {
1325                                                         if ( $.isArray( script ) ) {
1326                                                                 nestedAddScript( script, markModuleReady, 0 );
1327                                                         } else if ( typeof script === 'function' ) {
1328                                                                 // Pass jQuery twice so that the signature of the closure which wraps
1329                                                                 // the script can bind both '$' and 'jQuery'.
1330                                                                 script( $, $, mw.loader.require, registry[ module ].module );
1331                                                                 markModuleReady();
1332
1333                                                         } else if ( typeof script === 'string' ) {
1334                                                                 // Site and user modules are legacy scripts that run in the global scope.
1335                                                                 // This is transported as a string instead of a function to avoid needing
1336                                                                 // to use string manipulation to undo the function wrapper.
1337                                                                 $.globalEval( script );
1338                                                                 markModuleReady();
1339
1340                                                         } else {
1341                                                                 // Module without script
1342                                                                 markModuleReady();
1343                                                         }
1344                                                 } catch ( e ) {
1345                                                         // Use mw.track instead of mw.log because these errors are common in production mode
1346                                                         // (e.g. undefined variable), and mw.log is only enabled in debug mode.
1347                                                         registry[ module ].state = 'error';
1348                                                         mw.track( 'resourceloader.exception', { exception: e, module: module, source: 'module-execute' } );
1349                                                         handlePending( module );
1350                                                 }
1351                                         } );
1352                                 };
1353
1354                                 // Add localizations to message system
1355                                 if ( registry[ module ].messages ) {
1356                                         mw.messages.set( registry[ module ].messages );
1357                                 }
1358
1359                                 // Initialise templates
1360                                 if ( registry[ module ].templates ) {
1361                                         mw.templates.set( module, registry[ module ].templates );
1362                                 }
1363
1364                                 // Make sure we don't run the scripts until all stylesheet insertions have completed.
1365                                 ( function () {
1366                                         var pending = 0;
1367                                         checkCssHandles = function () {
1368                                                 // cssHandlesRegistered ensures we don't take off too soon, e.g. when
1369                                                 // one of the cssHandles is fired while we're still creating more handles.
1370                                                 if ( cssHandlesRegistered && pending === 0 && runScript ) {
1371                                                         runScript();
1372                                                         runScript = undefined; // Revoke
1373                                                 }
1374                                         };
1375                                         cssHandle = function () {
1376                                                 var check = checkCssHandles;
1377                                                 pending++;
1378                                                 return function () {
1379                                                         if ( check ) {
1380                                                                 pending--;
1381                                                                 check();
1382                                                                 check = undefined; // Revoke
1383                                                         }
1384                                                 };
1385                                         };
1386                                 }() );
1387
1388                                 // Process styles (see also mw.loader.implement)
1389                                 // * back-compat: { <media>: css }
1390                                 // * back-compat: { <media>: [url, ..] }
1391                                 // * { "css": [css, ..] }
1392                                 // * { "url": { <media>: [url, ..] } }
1393                                 if ( registry[ module ].style ) {
1394                                         for ( key in registry[ module ].style ) {
1395                                                 value = registry[ module ].style[ key ];
1396                                                 media = undefined;
1397
1398                                                 if ( key !== 'url' && key !== 'css' ) {
1399                                                         // Backwards compatibility, key is a media-type
1400                                                         if ( typeof value === 'string' ) {
1401                                                                 // back-compat: { <media>: css }
1402                                                                 // Ignore 'media' because it isn't supported (nor was it used).
1403                                                                 // Strings are pre-wrapped in "@media". The media-type was just ""
1404                                                                 // (because it had to be set to something).
1405                                                                 // This is one of the reasons why this format is no longer used.
1406                                                                 addEmbeddedCSS( value, cssHandle() );
1407                                                         } else {
1408                                                                 // back-compat: { <media>: [url, ..] }
1409                                                                 media = key;
1410                                                                 key = 'bc-url';
1411                                                         }
1412                                                 }
1413
1414                                                 // Array of css strings in key 'css',
1415                                                 // or back-compat array of urls from media-type
1416                                                 if ( $.isArray( value ) ) {
1417                                                         for ( i = 0; i < value.length; i++ ) {
1418                                                                 if ( key === 'bc-url' ) {
1419                                                                         // back-compat: { <media>: [url, ..] }
1420                                                                         addLink( media, value[ i ] );
1421                                                                 } else if ( key === 'css' ) {
1422                                                                         // { "css": [css, ..] }
1423                                                                         addEmbeddedCSS( value[ i ], cssHandle() );
1424                                                                 }
1425                                                         }
1426                                                 // Not an array, but a regular object
1427                                                 // Array of urls inside media-type key
1428                                                 } else if ( typeof value === 'object' ) {
1429                                                         // { "url": { <media>: [url, ..] } }
1430                                                         for ( media in value ) {
1431                                                                 urls = value[ media ];
1432                                                                 for ( i = 0; i < urls.length; i++ ) {
1433                                                                         addLink( media, urls[ i ] );
1434                                                                 }
1435                                                         }
1436                                                 }
1437                                         }
1438                                 }
1439
1440                                 // Kick off.
1441                                 cssHandlesRegistered = true;
1442                                 checkCssHandles();
1443                         }
1444
1445                         /**
1446                          * Add one or more modules to the module load queue.
1447                          *
1448                          * See also #work().
1449                          *
1450                          * @private
1451                          * @param {string|string[]} dependencies Module name or array of string module names
1452                          * @param {Function} [ready] Callback to execute when all dependencies are ready
1453                          * @param {Function} [error] Callback to execute when any dependency fails
1454                          */
1455                         function enqueue( dependencies, ready, error ) {
1456                                 // Allow calling by single module name
1457                                 if ( typeof dependencies === 'string' ) {
1458                                         dependencies = [ dependencies ];
1459                                 }
1460
1461                                 // Add ready and error callbacks if they were given
1462                                 if ( ready !== undefined || error !== undefined ) {
1463                                         jobs.push( {
1464                                                 // Narrow down the list to modules that are worth waiting for
1465                                                 dependencies: $.grep( dependencies, function ( module ) {
1466                                                         var state = mw.loader.getState( module );
1467                                                         return state === 'registered' || state === 'loaded' || state === 'loading' || state === 'executing';
1468                                                 } ),
1469                                                 ready: ready,
1470                                                 error: error
1471                                         } );
1472                                 }
1473
1474                                 $.each( dependencies, function ( idx, module ) {
1475                                         var state = mw.loader.getState( module );
1476                                         // Only queue modules that are still in the initial 'registered' state
1477                                         // (not ones already loading, ready or error).
1478                                         if ( state === 'registered' && $.inArray( module, queue ) === -1 ) {
1479                                                 // Private modules must be embedded in the page. Don't bother queuing
1480                                                 // these as the server will deny them anyway (T101806).
1481                                                 if ( registry[ module ].group === 'private' ) {
1482                                                         registry[ module ].state = 'error';
1483                                                         handlePending( module );
1484                                                         return;
1485                                                 }
1486                                                 queue.push( module );
1487                                         }
1488                                 } );
1489
1490                                 mw.loader.work();
1491                         }
1492
1493                         function sortQuery( o ) {
1494                                 var key,
1495                                         sorted = {},
1496                                         a = [];
1497
1498                                 for ( key in o ) {
1499                                         if ( hasOwn.call( o, key ) ) {
1500                                                 a.push( key );
1501                                         }
1502                                 }
1503                                 a.sort();
1504                                 for ( key = 0; key < a.length; key++ ) {
1505                                         sorted[ a[ key ] ] = o[ a[ key ] ];
1506                                 }
1507                                 return sorted;
1508                         }
1509
1510                         /**
1511                          * Converts a module map of the form { foo: [ 'bar', 'baz' ], bar: [ 'baz, 'quux' ] }
1512                          * to a query string of the form foo.bar,baz|bar.baz,quux
1513                          *
1514                          * @private
1515                          */
1516                         function buildModulesString( moduleMap ) {
1517                                 var p, prefix,
1518                                         arr = [];
1519
1520                                 for ( prefix in moduleMap ) {
1521                                         p = prefix === '' ? '' : prefix + '.';
1522                                         arr.push( p + moduleMap[ prefix ].join( ',' ) );
1523                                 }
1524                                 return arr.join( '|' );
1525                         }
1526
1527                         /**
1528                          * Make a network request to load modules from the server.
1529                          *
1530                          * @private
1531                          * @param {Object} moduleMap Module map, see #buildModulesString
1532                          * @param {Object} currReqBase Object with other parameters (other than 'modules') to use in the request
1533                          * @param {string} sourceLoadScript URL of load.php
1534                          */
1535                         function doRequest( moduleMap, currReqBase, sourceLoadScript ) {
1536                                 var query = $.extend(
1537                                         { modules: buildModulesString( moduleMap ) },
1538                                         currReqBase
1539                                 );
1540                                 query = sortQuery( query );
1541                                 addScript( sourceLoadScript + '?' + $.param( query ) );
1542                         }
1543
1544                         /**
1545                          * Resolve indexed dependencies.
1546                          *
1547                          * ResourceLoader uses an optimization to save space which replaces module names in
1548                          * dependency lists with the index of that module within the array of module
1549                          * registration data if it exists. The benefit is a significant reduction in the data
1550                          * size of the startup module. This function changes those dependency lists back to
1551                          * arrays of strings.
1552                          *
1553                          * @private
1554                          * @param {Array} modules Modules array
1555                          */
1556                         function resolveIndexedDependencies( modules ) {
1557                                 var i, j, deps;
1558                                 function resolveIndex( dep ) {
1559                                         return typeof dep === 'number' ? modules[ dep ][ 0 ] : dep;
1560                                 }
1561                                 for ( i = 0; i < modules.length; i++ ) {
1562                                         deps = modules[ i ][ 2 ];
1563                                         if ( deps ) {
1564                                                 for ( j = 0; j < deps.length; j++ ) {
1565                                                         deps[ j ] = resolveIndex( deps[ j ] );
1566                                                 }
1567                                         }
1568                                 }
1569                         }
1570
1571                         /**
1572                          * Create network requests for a batch of modules.
1573                          *
1574                          * This is an internal method for #work(). This must not be called directly
1575                          * unless the modules are already registered, and no request is in progress,
1576                          * and the module state has already been set to `loading`.
1577                          *
1578                          * @private
1579                          * @param {string[]} batch
1580                          */
1581                         function batchRequest( batch ) {
1582                                 var reqBase, splits, maxQueryLength, b, bSource, bGroup, bSourceGroup,
1583                                         source, group, i, modules, sourceLoadScript,
1584                                         currReqBase, currReqBaseLength, moduleMap, l,
1585                                         lastDotIndex, prefix, suffix, bytesAdded;
1586
1587                                 if ( !batch.length ) {
1588                                         return;
1589                                 }
1590
1591                                 // Always order modules alphabetically to help reduce cache
1592                                 // misses for otherwise identical content.
1593                                 batch.sort();
1594
1595                                 // Build a list of query parameters common to all requests
1596                                 reqBase = {
1597                                         skin: mw.config.get( 'skin' ),
1598                                         lang: mw.config.get( 'wgUserLanguage' ),
1599                                         debug: mw.config.get( 'debug' )
1600                                 };
1601                                 maxQueryLength = mw.config.get( 'wgResourceLoaderMaxQueryLength', 2000 );
1602
1603                                 // Split module list by source and by group.
1604                                 splits = {};
1605                                 for ( b = 0; b < batch.length; b++ ) {
1606                                         bSource = registry[ batch[ b ] ].source;
1607                                         bGroup = registry[ batch[ b ] ].group;
1608                                         if ( !hasOwn.call( splits, bSource ) ) {
1609                                                 splits[ bSource ] = {};
1610                                         }
1611                                         if ( !hasOwn.call( splits[ bSource ], bGroup ) ) {
1612                                                 splits[ bSource ][ bGroup ] = [];
1613                                         }
1614                                         bSourceGroup = splits[ bSource ][ bGroup ];
1615                                         bSourceGroup.push( batch[ b ] );
1616                                 }
1617
1618                                 for ( source in splits ) {
1619
1620                                         sourceLoadScript = sources[ source ];
1621
1622                                         for ( group in splits[ source ] ) {
1623
1624                                                 // Cache access to currently selected list of
1625                                                 // modules for this group from this source.
1626                                                 modules = splits[ source ][ group ];
1627
1628                                                 currReqBase = $.extend( {
1629                                                         version: getCombinedVersion( modules )
1630                                                 }, reqBase );
1631                                                 // For user modules append a user name to the query string.
1632                                                 if ( group === 'user' && mw.config.get( 'wgUserName' ) !== null ) {
1633                                                         currReqBase.user = mw.config.get( 'wgUserName' );
1634                                                 }
1635                                                 currReqBaseLength = $.param( currReqBase ).length;
1636                                                 // We may need to split up the request to honor the query string length limit,
1637                                                 // so build it piece by piece.
1638                                                 l = currReqBaseLength + 9; // '&modules='.length == 9
1639
1640                                                 moduleMap = {}; // { prefix: [ suffixes ] }
1641
1642                                                 for ( i = 0; i < modules.length; i++ ) {
1643                                                         // Determine how many bytes this module would add to the query string
1644                                                         lastDotIndex = modules[ i ].lastIndexOf( '.' );
1645
1646                                                         // If lastDotIndex is -1, substr() returns an empty string
1647                                                         prefix = modules[ i ].substr( 0, lastDotIndex );
1648                                                         suffix = modules[ i ].slice( lastDotIndex + 1 );
1649
1650                                                         bytesAdded = hasOwn.call( moduleMap, prefix )
1651                                                                 ? suffix.length + 3 // '%2C'.length == 3
1652                                                                 : modules[ i ].length + 3; // '%7C'.length == 3
1653
1654                                                         // If the url would become too long, create a new one,
1655                                                         // but don't create empty requests
1656                                                         if ( maxQueryLength > 0 && !$.isEmptyObject( moduleMap ) && l + bytesAdded > maxQueryLength ) {
1657                                                                 // This url would become too long, create a new one, and start the old one
1658                                                                 doRequest( moduleMap, currReqBase, sourceLoadScript );
1659                                                                 moduleMap = {};
1660                                                                 l = currReqBaseLength + 9;
1661                                                                 mw.track( 'resourceloader.splitRequest', { maxQueryLength: maxQueryLength } );
1662                                                         }
1663                                                         if ( !hasOwn.call( moduleMap, prefix ) ) {
1664                                                                 moduleMap[ prefix ] = [];
1665                                                         }
1666                                                         moduleMap[ prefix ].push( suffix );
1667                                                         l += bytesAdded;
1668                                                 }
1669                                                 // If there's anything left in moduleMap, request that too
1670                                                 if ( !$.isEmptyObject( moduleMap ) ) {
1671                                                         doRequest( moduleMap, currReqBase, sourceLoadScript );
1672                                                 }
1673                                         }
1674                                 }
1675                         }
1676
1677                         /* Public Members */
1678                         return {
1679                                 /**
1680                                  * The module registry is exposed as an aid for debugging and inspecting page
1681                                  * state; it is not a public interface for modifying the registry.
1682                                  *
1683                                  * @see #registry
1684                                  * @property
1685                                  * @private
1686                                  */
1687                                 moduleRegistry: registry,
1688
1689                                 /**
1690                                  * @inheritdoc #newStyleTag
1691                                  * @method
1692                                  */
1693                                 addStyleTag: newStyleTag,
1694
1695                                 /**
1696                                  * Start loading of all queued module dependencies.
1697                                  *
1698                                  * @protected
1699                                  */
1700                                 work: function () {
1701                                         var q, batch, concatSource, origBatch;
1702
1703                                         batch = [];
1704
1705                                         // Appends a list of modules from the queue to the batch
1706                                         for ( q = 0; q < queue.length; q++ ) {
1707                                                 // Only load modules which are registered
1708                                                 if ( hasOwn.call( registry, queue[ q ] ) && registry[ queue[ q ] ].state === 'registered' ) {
1709                                                         // Prevent duplicate entries
1710                                                         if ( $.inArray( queue[ q ], batch ) === -1 ) {
1711                                                                 batch.push( queue[ q ] );
1712                                                                 // Mark registered modules as loading
1713                                                                 registry[ queue[ q ] ].state = 'loading';
1714                                                         }
1715                                                 }
1716                                         }
1717
1718                                         // Now that the queue has been processed into a batch, clear the queue.
1719                                         // This MUST happen before we initiate any eval or network request. Otherwise,
1720                                         // it is possible for a cached script to instantly trigger the same work queue
1721                                         // again; all before we've cleared it causing each request to include modules
1722                                         // which are already loaded.
1723                                         queue = [];
1724
1725                                         if ( !batch.length ) {
1726                                                 return;
1727                                         }
1728
1729                                         mw.loader.store.init();
1730                                         if ( mw.loader.store.enabled ) {
1731                                                 concatSource = [];
1732                                                 origBatch = batch;
1733                                                 batch = $.grep( batch, function ( module ) {
1734                                                         var source = mw.loader.store.get( module );
1735                                                         if ( source ) {
1736                                                                 concatSource.push( source );
1737                                                                 return false;
1738                                                         }
1739                                                         return true;
1740                                                 } );
1741                                                 try {
1742                                                         $.globalEval( concatSource.join( ';' ) );
1743                                                 } catch ( err ) {
1744                                                         // Not good, the cached mw.loader.implement calls failed! This should
1745                                                         // never happen, barring ResourceLoader bugs, browser bugs and PEBKACs.
1746                                                         // Depending on how corrupt the string is, it is likely that some
1747                                                         // modules' implement() succeeded while the ones after the error will
1748                                                         // never run and leave their modules in the 'loading' state forever.
1749
1750                                                         // Since this is an error not caused by an individual module but by
1751                                                         // something that infected the implement call itself, don't take any
1752                                                         // risks and clear everything in this cache.
1753                                                         mw.loader.store.clear();
1754                                                         // Re-add the ones still pending back to the batch and let the server
1755                                                         // repopulate these modules to the cache.
1756                                                         // This means that at most one module will be useless (the one that had
1757                                                         // the error) instead of all of them.
1758                                                         mw.track( 'resourceloader.exception', { exception: err, source: 'store-eval' } );
1759                                                         origBatch = $.grep( origBatch, function ( module ) {
1760                                                                 return registry[ module ].state === 'loading';
1761                                                         } );
1762                                                         batch = batch.concat( origBatch );
1763                                                 }
1764                                         }
1765
1766                                         batchRequest( batch );
1767                                 },
1768
1769                                 /**
1770                                  * Register a source.
1771                                  *
1772                                  * The #work() method will use this information to split up requests by source.
1773                                  *
1774                                  *     mw.loader.addSource( 'mediawikiwiki', '//www.mediawiki.org/w/load.php' );
1775                                  *
1776                                  * @param {string|Object} id Source ID, or object mapping ids to load urls
1777                                  * @param {string} loadUrl Url to a load.php end point
1778                                  * @throws {Error} If source id is already registered
1779                                  */
1780                                 addSource: function ( id, loadUrl ) {
1781                                         var source;
1782                                         // Allow multiple additions
1783                                         if ( typeof id === 'object' ) {
1784                                                 for ( source in id ) {
1785                                                         mw.loader.addSource( source, id[ source ] );
1786                                                 }
1787                                                 return;
1788                                         }
1789
1790                                         if ( hasOwn.call( sources, id ) ) {
1791                                                 throw new Error( 'source already registered: ' + id );
1792                                         }
1793
1794                                         sources[ id ] = loadUrl;
1795                                 },
1796
1797                                 /**
1798                                  * Register a module, letting the system know about it and its properties.
1799                                  *
1800                                  * The startup modules contain calls to this method.
1801                                  *
1802                                  * When using multiple module registration by passing an array, dependencies that
1803                                  * are specified as references to modules within the array will be resolved before
1804                                  * the modules are registered.
1805                                  *
1806                                  * @param {string|Array} module Module name or array of arrays, each containing
1807                                  *  a list of arguments compatible with this method
1808                                  * @param {string|number} version Module version hash (falls backs to empty string)
1809                                  *  Can also be a number (timestamp) for compatibility with MediaWiki 1.25 and earlier.
1810                                  * @param {string|Array|Function} dependencies One string or array of strings of module
1811                                  *  names on which this module depends, or a function that returns that array.
1812                                  * @param {string} [group=null] Group which the module is in
1813                                  * @param {string} [source='local'] Name of the source
1814                                  * @param {string} [skip=null] Script body of the skip function
1815                                  */
1816                                 register: function ( module, version, dependencies, group, source, skip ) {
1817                                         var i, deps;
1818                                         // Allow multiple registration
1819                                         if ( typeof module === 'object' ) {
1820                                                 resolveIndexedDependencies( module );
1821                                                 for ( i = 0; i < module.length; i++ ) {
1822                                                         // module is an array of module names
1823                                                         if ( typeof module[ i ] === 'string' ) {
1824                                                                 mw.loader.register( module[ i ] );
1825                                                         // module is an array of arrays
1826                                                         } else if ( typeof module[ i ] === 'object' ) {
1827                                                                 mw.loader.register.apply( mw.loader, module[ i ] );
1828                                                         }
1829                                                 }
1830                                                 return;
1831                                         }
1832                                         if ( hasOwn.call( registry, module ) ) {
1833                                                 throw new Error( 'module already registered: ' + module );
1834                                         }
1835                                         if ( typeof dependencies === 'string' ) {
1836                                                 // A single module name
1837                                                 deps = [ dependencies ];
1838                                         } else if ( typeof dependencies === 'object' || typeof dependencies === 'function' ) {
1839                                                 // Array of module names or a function that returns an array
1840                                                 deps = dependencies;
1841                                         }
1842                                         // List the module as registered
1843                                         registry[ module ] = {
1844                                                 // Exposed to execute() for mw.loader.implement() closures.
1845                                                 // Import happens via require().
1846                                                 module: {
1847                                                         exports: {}
1848                                                 },
1849                                                 version: version !== undefined ? String( version ) : '',
1850                                                 dependencies: deps || [],
1851                                                 group: typeof group === 'string' ? group : null,
1852                                                 source: typeof source === 'string' ? source : 'local',
1853                                                 state: 'registered',
1854                                                 skip: typeof skip === 'string' ? skip : null
1855                                         };
1856                                 },
1857
1858                                 /**
1859                                  * Implement a module given the components that make up the module.
1860                                  *
1861                                  * When #load() or #using() requests one or more modules, the server
1862                                  * response contain calls to this function.
1863                                  *
1864                                  * @param {string} module Name of module
1865                                  * @param {Function|Array|string} [script] Function with module code, list of URLs
1866                                  *  to load via `<script src>`, or string of module code for `$.globalEval()`.
1867                                  * @param {Object} [style] Should follow one of the following patterns:
1868                                  *
1869                                  *     { "css": [css, ..] }
1870                                  *     { "url": { <media>: [url, ..] } }
1871                                  *
1872                                  * And for backwards compatibility (needs to be supported forever due to caching):
1873                                  *
1874                                  *     { <media>: css }
1875                                  *     { <media>: [url, ..] }
1876                                  *
1877                                  * The reason css strings are not concatenated anymore is bug 31676. We now check
1878                                  * whether it's safe to extend the stylesheet.
1879                                  *
1880                                  * @protected
1881                                  * @param {Object} [messages] List of key/value pairs to be added to mw#messages.
1882                                  * @param {Object} [templates] List of key/value pairs to be added to mw#templates.
1883                                  */
1884                                 implement: function ( module, script, style, messages, templates ) {
1885                                         // Automatically register module
1886                                         if ( !hasOwn.call( registry, module ) ) {
1887                                                 mw.loader.register( module );
1888                                         }
1889                                         // Check for duplicate implementation
1890                                         if ( hasOwn.call( registry, module ) && registry[ module ].script !== undefined ) {
1891                                                 throw new Error( 'module already implemented: ' + module );
1892                                         }
1893                                         // Attach components
1894                                         registry[ module ].script = script || null;
1895                                         registry[ module ].style = style || null;
1896                                         registry[ module ].messages = messages || null;
1897                                         registry[ module ].templates = templates || null;
1898                                         // The module may already have been marked as erroneous
1899                                         if ( $.inArray( registry[ module ].state, [ 'error', 'missing' ] ) === -1 ) {
1900                                                 registry[ module ].state = 'loaded';
1901                                                 if ( allReady( registry[ module ].dependencies ) ) {
1902                                                         execute( module );
1903                                                 }
1904                                         }
1905                                 },
1906
1907                                 /**
1908                                  * Execute a function as soon as one or more required modules are ready.
1909                                  *
1910                                  * Example of inline dependency on OOjs:
1911                                  *
1912                                  *     mw.loader.using( 'oojs', function () {
1913                                  *         OO.compare( [ 1 ], [ 1 ] );
1914                                  *     } );
1915                                  *
1916                                  * Since MediaWiki 1.23 this also returns a promise.
1917                                  *
1918                                  * Since MediaWiki 1.28 the promise is resolved with a `require` function.
1919                                  *
1920                                  * @param {string|Array} dependencies Module name or array of modules names the
1921                                  *  callback depends on to be ready before executing
1922                                  * @param {Function} [ready] Callback to execute when all dependencies are ready
1923                                  * @param {Function} [error] Callback to execute if one or more dependencies failed
1924                                  * @return {jQuery.Promise} With a `require` function
1925                                  */
1926                                 using: function ( dependencies, ready, error ) {
1927                                         var deferred = $.Deferred();
1928
1929                                         // Allow calling with a single dependency as a string
1930                                         if ( typeof dependencies === 'string' ) {
1931                                                 dependencies = [ dependencies ];
1932                                         }
1933
1934                                         if ( ready ) {
1935                                                 deferred.done( ready );
1936                                         }
1937                                         if ( error ) {
1938                                                 deferred.fail( error );
1939                                         }
1940
1941                                         // Resolve entire dependency map
1942                                         dependencies = resolve( dependencies );
1943                                         if ( allReady( dependencies ) ) {
1944                                                 // Run ready immediately
1945                                                 deferred.resolve( mw.loader.require );
1946                                         } else if ( anyFailed( dependencies ) ) {
1947                                                 // Execute error immediately if any dependencies have errors
1948                                                 deferred.reject(
1949                                                         new Error( 'One or more dependencies failed to load' ),
1950                                                         dependencies
1951                                                 );
1952                                         } else {
1953                                                 // Not all dependencies are ready, add to the load queue
1954                                                 enqueue( dependencies, function () {
1955                                                         deferred.resolve( mw.loader.require );
1956                                                 }, deferred.reject );
1957                                         }
1958
1959                                         return deferred.promise();
1960                                 },
1961
1962                                 /**
1963                                  * Load an external script or one or more modules.
1964                                  *
1965                                  * @param {string|Array} modules Either the name of a module, array of modules,
1966                                  *  or a URL of an external script or style
1967                                  * @param {string} [type='text/javascript'] MIME type to use if calling with a URL of an
1968                                  *  external script or style; acceptable values are "text/css" and
1969                                  *  "text/javascript"; if no type is provided, text/javascript is assumed.
1970                                  */
1971                                 load: function ( modules, type ) {
1972                                         var filtered, l;
1973
1974                                         // Allow calling with a url or single dependency as a string
1975                                         if ( typeof modules === 'string' ) {
1976                                                 // "https://example.org/x.js", "http://example.org/x.js", "//example.org/x.js", "/x.js"
1977                                                 if ( /^(https?:)?\/?\//.test( modules ) ) {
1978                                                         if ( type === 'text/css' ) {
1979                                                                 // Support: IE 7-8
1980                                                                 // Use properties instead of attributes as IE throws security
1981                                                                 // warnings when inserting a <link> tag with a protocol-relative
1982                                                                 // URL set though attributes - when on HTTPS. See bug 41331.
1983                                                                 l = document.createElement( 'link' );
1984                                                                 l.rel = 'stylesheet';
1985                                                                 l.href = modules;
1986                                                                 $( 'head' ).append( l );
1987                                                                 return;
1988                                                         }
1989                                                         if ( type === 'text/javascript' || type === undefined ) {
1990                                                                 addScript( modules );
1991                                                                 return;
1992                                                         }
1993                                                         // Unknown type
1994                                                         throw new Error( 'invalid type for external url, must be text/css or text/javascript. not ' + type );
1995                                                 }
1996                                                 // Called with single module
1997                                                 modules = [ modules ];
1998                                         }
1999
2000                                         // Filter out undefined modules, otherwise resolve() will throw
2001                                         // an exception for trying to load an undefined module.
2002                                         // Undefined modules are acceptable here in load(), because load() takes
2003                                         // an array of unrelated modules, whereas the modules passed to
2004                                         // using() are related and must all be loaded.
2005                                         filtered = $.grep( modules, function ( module ) {
2006                                                 var state = mw.loader.getState( module );
2007                                                 return state !== null && state !== 'error' && state !== 'missing';
2008                                         } );
2009
2010                                         if ( filtered.length === 0 ) {
2011                                                 return;
2012                                         }
2013                                         // Resolve entire dependency map
2014                                         filtered = resolve( filtered );
2015                                         // If all modules are ready, or if any modules have errors, nothing to be done.
2016                                         if ( allReady( filtered ) || anyFailed( filtered ) ) {
2017                                                 return;
2018                                         }
2019                                         // Some modules are not yet ready, add to module load queue.
2020                                         enqueue( filtered, undefined, undefined );
2021                                 },
2022
2023                                 /**
2024                                  * Change the state of one or more modules.
2025                                  *
2026                                  * @param {string|Object} module Module name or object of module name/state pairs
2027                                  * @param {string} state State name
2028                                  */
2029                                 state: function ( module, state ) {
2030                                         var m;
2031
2032                                         if ( typeof module === 'object' ) {
2033                                                 for ( m in module ) {
2034                                                         mw.loader.state( m, module[ m ] );
2035                                                 }
2036                                                 return;
2037                                         }
2038                                         if ( !hasOwn.call( registry, module ) ) {
2039                                                 mw.loader.register( module );
2040                                         }
2041                                         registry[ module ].state = state;
2042                                         if ( $.inArray( state, [ 'ready', 'error', 'missing' ] ) !== -1 ) {
2043                                                 // Make sure pending modules depending on this one get executed if their
2044                                                 // dependencies are now fulfilled!
2045                                                 handlePending( module );
2046                                         }
2047                                 },
2048
2049                                 /**
2050                                  * Get the version of a module.
2051                                  *
2052                                  * @param {string} module Name of module
2053                                  * @return {string|null} The version, or null if the module (or its version) is not
2054                                  *  in the registry.
2055                                  */
2056                                 getVersion: function ( module ) {
2057                                         if ( !hasOwn.call( registry, module ) || registry[ module ].version === undefined ) {
2058                                                 return null;
2059                                         }
2060                                         return registry[ module ].version;
2061                                 },
2062
2063                                 /**
2064                                  * Get the state of a module.
2065                                  *
2066                                  * @param {string} module Name of module
2067                                  * @return {string|null} The state, or null if the module (or its state) is not
2068                                  *  in the registry.
2069                                  */
2070                                 getState: function ( module ) {
2071                                         if ( !hasOwn.call( registry, module ) || registry[ module ].state === undefined ) {
2072                                                 return null;
2073                                         }
2074                                         return registry[ module ].state;
2075                                 },
2076
2077                                 /**
2078                                  * Get the names of all registered modules.
2079                                  *
2080                                  * @return {Array}
2081                                  */
2082                                 getModuleNames: function () {
2083                                         return $.map( registry, function ( i, key ) {
2084                                                 return key;
2085                                         } );
2086                                 },
2087
2088                                 /**
2089                                  * Get the exported value of a module.
2090                                  *
2091                                  * Modules may provide this via their local `module.exports`.
2092                                  *
2093                                  * @protected
2094                                  * @since 1.27
2095                                  */
2096                                 require: function ( moduleName ) {
2097                                         var state = mw.loader.getState( moduleName );
2098
2099                                         // Only ready modules can be required
2100                                         if ( state !== 'ready' ) {
2101                                                 // Module may've forgotten to declare a dependency
2102                                                 throw new Error( 'Module "' + moduleName + '" is not loaded.' );
2103                                         }
2104
2105                                         return registry[ moduleName ].module.exports;
2106                                 },
2107
2108                                 /**
2109                                  * @inheritdoc mw.inspect#runReports
2110                                  * @method
2111                                  */
2112                                 inspect: function () {
2113                                         var args = slice.call( arguments );
2114                                         mw.loader.using( 'mediawiki.inspect', function () {
2115                                                 mw.inspect.runReports.apply( mw.inspect, args );
2116                                         } );
2117                                 },
2118
2119                                 /**
2120                                  * On browsers that implement the localStorage API, the module store serves as a
2121                                  * smart complement to the browser cache. Unlike the browser cache, the module store
2122                                  * can slice a concatenated response from ResourceLoader into its constituent
2123                                  * modules and cache each of them separately, using each module's versioning scheme
2124                                  * to determine when the cache should be invalidated.
2125                                  *
2126                                  * @singleton
2127                                  * @class mw.loader.store
2128                                  */
2129                                 store: {
2130                                         // Whether the store is in use on this page.
2131                                         enabled: null,
2132
2133                                         MODULE_SIZE_MAX: 100 * 1000,
2134
2135                                         // The contents of the store, mapping '[module name]@[version]' keys
2136                                         // to module implementations.
2137                                         items: {},
2138
2139                                         // Cache hit stats
2140                                         stats: { hits: 0, misses: 0, expired: 0 },
2141
2142                                         /**
2143                                          * Construct a JSON-serializable object representing the content of the store.
2144                                          *
2145                                          * @return {Object} Module store contents.
2146                                          */
2147                                         toJSON: function () {
2148                                                 return { items: mw.loader.store.items, vary: mw.loader.store.getVary() };
2149                                         },
2150
2151                                         /**
2152                                          * Get the localStorage key for the entire module store. The key references
2153                                          * $wgDBname to prevent clashes between wikis which share a common host.
2154                                          *
2155                                          * @return {string} localStorage item key
2156                                          */
2157                                         getStoreKey: function () {
2158                                                 return 'MediaWikiModuleStore:' + mw.config.get( 'wgDBname' );
2159                                         },
2160
2161                                         /**
2162                                          * Get a key on which to vary the module cache.
2163                                          *
2164                                          * @return {string} String of concatenated vary conditions.
2165                                          */
2166                                         getVary: function () {
2167                                                 return [
2168                                                         mw.config.get( 'skin' ),
2169                                                         mw.config.get( 'wgResourceLoaderStorageVersion' ),
2170                                                         mw.config.get( 'wgUserLanguage' )
2171                                                 ].join( ':' );
2172                                         },
2173
2174                                         /**
2175                                          * Get a key for a specific module. The key format is '[name]@[version]'.
2176                                          *
2177                                          * @param {string} module Module name
2178                                          * @return {string|null} Module key or null if module does not exist
2179                                          */
2180                                         getModuleKey: function ( module ) {
2181                                                 return hasOwn.call( registry, module ) ?
2182                                                         ( module + '@' + registry[ module ].version ) : null;
2183                                         },
2184
2185                                         /**
2186                                          * Initialize the store.
2187                                          *
2188                                          * Retrieves store from localStorage and (if successfully retrieved) decoding
2189                                          * the stored JSON value to a plain object.
2190                                          *
2191                                          * The try / catch block is used for JSON & localStorage feature detection.
2192                                          * See the in-line documentation for Modernizr's localStorage feature detection
2193                                          * code for a full account of why we need a try / catch:
2194                                          * <https://github.com/Modernizr/Modernizr/blob/v2.7.1/modernizr.js#L771-L796>.
2195                                          */
2196                                         init: function () {
2197                                                 var raw, data;
2198
2199                                                 if ( mw.loader.store.enabled !== null ) {
2200                                                         // Init already ran
2201                                                         return;
2202                                                 }
2203
2204                                                 if (
2205                                                         // Disabled because localStorage quotas are tight and (in Firefox's case)
2206                                                         // shared by multiple origins.
2207                                                         // See T66721, and <https://bugzilla.mozilla.org/show_bug.cgi?id=1064466>.
2208                                                         /Firefox|Opera/.test( navigator.userAgent ) ||
2209
2210                                                         // Disabled by configuration.
2211                                                         !mw.config.get( 'wgResourceLoaderStorageEnabled' )
2212                                                 ) {
2213                                                         // Clear any previous store to free up space. (T66721)
2214                                                         mw.loader.store.clear();
2215                                                         mw.loader.store.enabled = false;
2216                                                         return;
2217                                                 }
2218                                                 if ( mw.config.get( 'debug' ) ) {
2219                                                         // Disable module store in debug mode
2220                                                         mw.loader.store.enabled = false;
2221                                                         return;
2222                                                 }
2223
2224                                                 try {
2225                                                         raw = localStorage.getItem( mw.loader.store.getStoreKey() );
2226                                                         // If we get here, localStorage is available; mark enabled
2227                                                         mw.loader.store.enabled = true;
2228                                                         data = JSON.parse( raw );
2229                                                         if ( data && typeof data.items === 'object' && data.vary === mw.loader.store.getVary() ) {
2230                                                                 mw.loader.store.items = data.items;
2231                                                                 return;
2232                                                         }
2233                                                 } catch ( e ) {
2234                                                         mw.track( 'resourceloader.exception', { exception: e, source: 'store-localstorage-init' } );
2235                                                 }
2236
2237                                                 if ( raw === undefined ) {
2238                                                         // localStorage failed; disable store
2239                                                         mw.loader.store.enabled = false;
2240                                                 } else {
2241                                                         mw.loader.store.update();
2242                                                 }
2243                                         },
2244
2245                                         /**
2246                                          * Retrieve a module from the store and update cache hit stats.
2247                                          *
2248                                          * @param {string} module Module name
2249                                          * @return {string|boolean} Module implementation or false if unavailable
2250                                          */
2251                                         get: function ( module ) {
2252                                                 var key;
2253
2254                                                 if ( !mw.loader.store.enabled ) {
2255                                                         return false;
2256                                                 }
2257
2258                                                 key = mw.loader.store.getModuleKey( module );
2259                                                 if ( key in mw.loader.store.items ) {
2260                                                         mw.loader.store.stats.hits++;
2261                                                         return mw.loader.store.items[ key ];
2262                                                 }
2263                                                 mw.loader.store.stats.misses++;
2264                                                 return false;
2265                                         },
2266
2267                                         /**
2268                                          * Stringify a module and queue it for storage.
2269                                          *
2270                                          * @param {string} module Module name
2271                                          * @param {Object} descriptor The module's descriptor as set in the registry
2272                                          */
2273                                         set: function ( module, descriptor ) {
2274                                                 var args, key, src;
2275
2276                                                 if ( !mw.loader.store.enabled ) {
2277                                                         return false;
2278                                                 }
2279
2280                                                 key = mw.loader.store.getModuleKey( module );
2281
2282                                                 if (
2283                                                         // Already stored a copy of this exact version
2284                                                         key in mw.loader.store.items ||
2285                                                         // Module failed to load
2286                                                         descriptor.state !== 'ready' ||
2287                                                         // Unversioned, private, or site-/user-specific
2288                                                         ( !descriptor.version || $.inArray( descriptor.group, [ 'private', 'user' ] ) !== -1 ) ||
2289                                                         // Partial descriptor
2290                                                         // (e.g. skipped module, or style module with state=ready)
2291                                                         $.inArray( undefined, [ descriptor.script, descriptor.style,
2292                                                                         descriptor.messages, descriptor.templates ] ) !== -1
2293                                                 ) {
2294                                                         // Decline to store
2295                                                         return false;
2296                                                 }
2297
2298                                                 try {
2299                                                         args = [
2300                                                                 JSON.stringify( module ),
2301                                                                 typeof descriptor.script === 'function' ?
2302                                                                         String( descriptor.script ) :
2303                                                                         JSON.stringify( descriptor.script ),
2304                                                                 JSON.stringify( descriptor.style ),
2305                                                                 JSON.stringify( descriptor.messages ),
2306                                                                 JSON.stringify( descriptor.templates )
2307                                                         ];
2308                                                         // Attempted workaround for a possible Opera bug (bug T59567).
2309                                                         // This regex should never match under sane conditions.
2310                                                         if ( /^\s*\(/.test( args[ 1 ] ) ) {
2311                                                                 args[ 1 ] = 'function' + args[ 1 ];
2312                                                                 mw.track( 'resourceloader.assert', { source: 'bug-T59567' } );
2313                                                         }
2314                                                 } catch ( e ) {
2315                                                         mw.track( 'resourceloader.exception', { exception: e, source: 'store-localstorage-json' } );
2316                                                         return;
2317                                                 }
2318
2319                                                 src = 'mw.loader.implement(' + args.join( ',' ) + ');';
2320                                                 if ( src.length > mw.loader.store.MODULE_SIZE_MAX ) {
2321                                                         return false;
2322                                                 }
2323                                                 mw.loader.store.items[ key ] = src;
2324                                                 mw.loader.store.update();
2325                                         },
2326
2327                                         /**
2328                                          * Iterate through the module store, removing any item that does not correspond
2329                                          * (in name and version) to an item in the module registry.
2330                                          */
2331                                         prune: function () {
2332                                                 var key, module;
2333
2334                                                 if ( !mw.loader.store.enabled ) {
2335                                                         return false;
2336                                                 }
2337
2338                                                 for ( key in mw.loader.store.items ) {
2339                                                         module = key.slice( 0, key.indexOf( '@' ) );
2340                                                         if ( mw.loader.store.getModuleKey( module ) !== key ) {
2341                                                                 mw.loader.store.stats.expired++;
2342                                                                 delete mw.loader.store.items[ key ];
2343                                                         } else if ( mw.loader.store.items[ key ].length > mw.loader.store.MODULE_SIZE_MAX ) {
2344                                                                 // This value predates the enforcement of a size limit on cached modules.
2345                                                                 delete mw.loader.store.items[ key ];
2346                                                         }
2347                                                 }
2348                                         },
2349
2350                                         /**
2351                                          * Clear the entire module store right now.
2352                                          */
2353                                         clear: function () {
2354                                                 mw.loader.store.items = {};
2355                                                 try {
2356                                                         localStorage.removeItem( mw.loader.store.getStoreKey() );
2357                                                 } catch ( ignored ) {}
2358                                         },
2359
2360                                         /**
2361                                          * Sync in-memory store back to localStorage.
2362                                          *
2363                                          * This function debounces updates. When called with a flush already pending,
2364                                          * the call is coalesced into the pending update. The call to
2365                                          * localStorage.setItem will be naturally deferred until the page is quiescent.
2366                                          *
2367                                          * Because localStorage is shared by all pages from the same origin, if multiple
2368                                          * pages are loaded with different module sets, the possibility exists that
2369                                          * modules saved by one page will be clobbered by another. But the impact would
2370                                          * be minor and the problem would be corrected by subsequent page views.
2371                                          *
2372                                          * @method
2373                                          */
2374                                         update: ( function () {
2375                                                 var hasPendingWrite = false;
2376
2377                                                 function flushWrites() {
2378                                                         var data, key;
2379                                                         if ( !hasPendingWrite || !mw.loader.store.enabled ) {
2380                                                                 return;
2381                                                         }
2382
2383                                                         mw.loader.store.prune();
2384                                                         key = mw.loader.store.getStoreKey();
2385                                                         try {
2386                                                                 // Replacing the content of the module store might fail if the new
2387                                                                 // contents would exceed the browser's localStorage size limit. To
2388                                                                 // avoid clogging the browser with stale data, always remove the old
2389                                                                 // value before attempting to set the new one.
2390                                                                 localStorage.removeItem( key );
2391                                                                 data = JSON.stringify( mw.loader.store );
2392                                                                 localStorage.setItem( key, data );
2393                                                         } catch ( e ) {
2394                                                                 mw.track( 'resourceloader.exception', { exception: e, source: 'store-localstorage-update' } );
2395                                                         }
2396
2397                                                         hasPendingWrite = false;
2398                                                 }
2399
2400                                                 return function () {
2401                                                         if ( !hasPendingWrite ) {
2402                                                                 hasPendingWrite = true;
2403                                                                 mw.requestIdleCallback( flushWrites );
2404                                                         }
2405                                                 };
2406                                         }() )
2407                                 }
2408                         };
2409                 }() ),
2410
2411                 /**
2412                  * HTML construction helper functions
2413                  *
2414                  *     @example
2415                  *
2416                  *     var Html, output;
2417                  *
2418                  *     Html = mw.html;
2419                  *     output = Html.element( 'div', {}, new Html.Raw(
2420                  *         Html.element( 'img', { src: '<' } )
2421                  *     ) );
2422                  *     mw.log( output ); // <div><img src="&lt;"/></div>
2423                  *
2424                  * @class mw.html
2425                  * @singleton
2426                  */
2427                 html: ( function () {
2428                         function escapeCallback( s ) {
2429                                 switch ( s ) {
2430                                         case '\'':
2431                                                 return '&#039;';
2432                                         case '"':
2433                                                 return '&quot;';
2434                                         case '<':
2435                                                 return '&lt;';
2436                                         case '>':
2437                                                 return '&gt;';
2438                                         case '&':
2439                                                 return '&amp;';
2440                                 }
2441                         }
2442
2443                         return {
2444                                 /**
2445                                  * Escape a string for HTML.
2446                                  *
2447                                  * Converts special characters to HTML entities.
2448                                  *
2449                                  *     mw.html.escape( '< > \' & "' );
2450                                  *     // Returns &lt; &gt; &#039; &amp; &quot;
2451                                  *
2452                                  * @param {string} s The string to escape
2453                                  * @return {string} HTML
2454                                  */
2455                                 escape: function ( s ) {
2456                                         return s.replace( /['"<>&]/g, escapeCallback );
2457                                 },
2458
2459                                 /**
2460                                  * Create an HTML element string, with safe escaping.
2461                                  *
2462                                  * @param {string} name The tag name.
2463                                  * @param {Object} [attrs] An object with members mapping element names to values
2464                                  * @param {string|mw.html.Raw|mw.html.Cdata|null} [contents=null] The contents of the element.
2465                                  *
2466                                  *  - string: Text to be escaped.
2467                                  *  - null: The element is treated as void with short closing form, e.g. `<br/>`.
2468                                  *  - this.Raw: The raw value is directly included.
2469                                  *  - this.Cdata: The raw value is directly included. An exception is
2470                                  *    thrown if it contains any illegal ETAGO delimiter.
2471                                  *    See <http://www.w3.org/TR/html401/appendix/notes.html#h-B.3.2>.
2472                                  * @return {string} HTML
2473                                  */
2474                                 element: function ( name, attrs, contents ) {
2475                                         var v, attrName, s = '<' + name;
2476
2477                                         if ( attrs ) {
2478                                                 for ( attrName in attrs ) {
2479                                                         v = attrs[ attrName ];
2480                                                         // Convert name=true, to name=name
2481                                                         if ( v === true ) {
2482                                                                 v = attrName;
2483                                                         // Skip name=false
2484                                                         } else if ( v === false ) {
2485                                                                 continue;
2486                                                         }
2487                                                         s += ' ' + attrName + '="' + this.escape( String( v ) ) + '"';
2488                                                 }
2489                                         }
2490                                         if ( contents === undefined || contents === null ) {
2491                                                 // Self close tag
2492                                                 s += '/>';
2493                                                 return s;
2494                                         }
2495                                         // Regular open tag
2496                                         s += '>';
2497                                         switch ( typeof contents ) {
2498                                                 case 'string':
2499                                                         // Escaped
2500                                                         s += this.escape( contents );
2501                                                         break;
2502                                                 case 'number':
2503                                                 case 'boolean':
2504                                                         // Convert to string
2505                                                         s += String( contents );
2506                                                         break;
2507                                                 default:
2508                                                         if ( contents instanceof this.Raw ) {
2509                                                                 // Raw HTML inclusion
2510                                                                 s += contents.value;
2511                                                         } else if ( contents instanceof this.Cdata ) {
2512                                                                 // CDATA
2513                                                                 if ( /<\/[a-zA-z]/.test( contents.value ) ) {
2514                                                                         throw new Error( 'mw.html.element: Illegal end tag found in CDATA' );
2515                                                                 }
2516                                                                 s += contents.value;
2517                                                         } else {
2518                                                                 throw new Error( 'mw.html.element: Invalid type of contents' );
2519                                                         }
2520                                         }
2521                                         s += '</' + name + '>';
2522                                         return s;
2523                                 },
2524
2525                                 /**
2526                                  * Wrapper object for raw HTML passed to mw.html.element().
2527                                  *
2528                                  * @class mw.html.Raw
2529                                  */
2530                                 Raw: function ( value ) {
2531                                         this.value = value;
2532                                 },
2533
2534                                 /**
2535                                  * Wrapper object for CDATA element contents passed to mw.html.element()
2536                                  *
2537                                  * @class mw.html.Cdata
2538                                  */
2539                                 Cdata: function ( value ) {
2540                                         this.value = value;
2541                                 }
2542                         };
2543                 }() ),
2544
2545                 // Skeleton user object, extended by the 'mediawiki.user' module.
2546                 /**
2547                  * @class mw.user
2548                  * @singleton
2549                  */
2550                 user: {
2551                         /**
2552                          * @property {mw.Map}
2553                          */
2554                         options: new Map(),
2555                         /**
2556                          * @property {mw.Map}
2557                          */
2558                         tokens: new Map()
2559                 },
2560
2561                 // OOUI widgets specific to MediaWiki
2562                 widgets: {},
2563
2564                 /**
2565                  * Registry and firing of events.
2566                  *
2567                  * MediaWiki has various interface components that are extended, enhanced
2568                  * or manipulated in some other way by extensions, gadgets and even
2569                  * in core itself.
2570                  *
2571                  * This framework helps streamlining the timing of when these other
2572                  * code paths fire their plugins (instead of using document-ready,
2573                  * which can and should be limited to firing only once).
2574                  *
2575                  * Features like navigating to other wiki pages, previewing an edit
2576                  * and editing itself – without a refresh – can then retrigger these
2577                  * hooks accordingly to ensure everything still works as expected.
2578                  *
2579                  * Example usage:
2580                  *
2581                  *     mw.hook( 'wikipage.content' ).add( fn ).remove( fn );
2582                  *     mw.hook( 'wikipage.content' ).fire( $content );
2583                  *
2584                  * Handlers can be added and fired for arbitrary event names at any time. The same
2585                  * event can be fired multiple times. The last run of an event is memorized
2586                  * (similar to `$(document).ready` and `$.Deferred().done`).
2587                  * This means if an event is fired, and a handler added afterwards, the added
2588                  * function will be fired right away with the last given event data.
2589                  *
2590                  * Like Deferreds and Promises, the mw.hook object is both detachable and chainable.
2591                  * Thus allowing flexible use and optimal maintainability and authority control.
2592                  * You can pass around the `add` and/or `fire` method to another piece of code
2593                  * without it having to know the event name (or `mw.hook` for that matter).
2594                  *
2595                  *     var h = mw.hook( 'bar.ready' );
2596                  *     new mw.Foo( .. ).fetch( { callback: h.fire } );
2597                  *
2598                  * Note: Events are documented with an underscore instead of a dot in the event
2599                  * name due to jsduck not supporting dots in that position.
2600                  *
2601                  * @class mw.hook
2602                  */
2603                 hook: ( function () {
2604                         var lists = {};
2605
2606                         /**
2607                          * Create an instance of mw.hook.
2608                          *
2609                          * @method hook
2610                          * @member mw
2611                          * @param {string} name Name of hook.
2612                          * @return {mw.hook}
2613                          */
2614                         return function ( name ) {
2615                                 var list = hasOwn.call( lists, name ) ?
2616                                         lists[ name ] :
2617                                         lists[ name ] = $.Callbacks( 'memory' );
2618
2619                                 return {
2620                                         /**
2621                                          * Register a hook handler
2622                                          *
2623                                          * @param {...Function} handler Function to bind.
2624                                          * @chainable
2625                                          */
2626                                         add: list.add,
2627
2628                                         /**
2629                                          * Unregister a hook handler
2630                                          *
2631                                          * @param {...Function} handler Function to unbind.
2632                                          * @chainable
2633                                          */
2634                                         remove: list.remove,
2635
2636                                         /**
2637                                          * Run a hook.
2638                                          *
2639                                          * @param {...Mixed} data
2640                                          * @chainable
2641                                          */
2642                                         fire: function () {
2643                                                 return list.fireWith.call( this, null, slice.call( arguments ) );
2644                                         }
2645                                 };
2646                         };
2647                 }() )
2648         };
2649
2650         // Alias $j to jQuery for backwards compatibility
2651         // @deprecated since 1.23 Use $ or jQuery instead
2652         mw.log.deprecate( window, '$j', $, 'Use $ or jQuery instead.' );
2653
2654         /**
2655          * Log a message to window.console, if possible.
2656          *
2657          * Useful to force logging of some errors that are otherwise hard to detect (i.e., this logs
2658          * also in production mode). Gets console references in each invocation instead of caching the
2659          * reference, so that debugging tools loaded later are supported (e.g. Firebug Lite in IE).
2660          *
2661          * @private
2662          * @param {string} topic Stream name passed by mw.track
2663          * @param {Object} data Data passed by mw.track
2664          * @param {Error} [data.exception]
2665          * @param {string} data.source Error source
2666          * @param {string} [data.module] Name of module which caused the error
2667          */
2668         function logError( topic, data ) {
2669                 var msg,
2670                         e = data.exception,
2671                         source = data.source,
2672                         module = data.module,
2673                         console = window.console;
2674
2675                 if ( console && console.log ) {
2676                         msg = ( e ? 'Exception' : 'Error' ) + ' in ' + source;
2677                         if ( module ) {
2678                                 msg += ' in module ' + module;
2679                         }
2680                         msg += ( e ? ':' : '.' );
2681                         console.log( msg );
2682
2683                         // If we have an exception object, log it to the error channel to trigger
2684                         // proper stacktraces in browsers that support it. No fallback as we have
2685                         // no browsers that don't support error(), but do support log().
2686                         if ( e && console.error ) {
2687                                 console.error( String( e ), e );
2688                         }
2689                 }
2690         }
2691
2692         // Subscribe to error streams
2693         mw.trackSubscribe( 'resourceloader.exception', logError );
2694         mw.trackSubscribe( 'resourceloader.assert', logError );
2695
2696         /**
2697          * Fired when all modules associated with the page have finished loading.
2698          *
2699          * @event resourceloader_loadEnd
2700          * @member mw.hook
2701          */
2702         $( function () {
2703                 var loading = $.grep( mw.loader.getModuleNames(), function ( module ) {
2704                         return mw.loader.getState( module ) === 'loading';
2705                 } );
2706                 // We only need a callback, not any actual module. First try a single using()
2707                 // for all loading modules. If one fails, fall back to tracking each module
2708                 // separately via $.when(), this is expensive.
2709                 loading = mw.loader.using( loading ).then( null, function () {
2710                         var all = $.map( loading, function ( module ) {
2711                                 return mw.loader.using( module ).then( null, function () {
2712                                         return $.Deferred().resolve();
2713                                 } );
2714                         } );
2715                         return $.when.apply( $, all );
2716                 } );
2717                 loading.then( function () {
2718                         mwPerformance.mark( 'mwLoadEnd' );
2719                         mw.hook( 'resourceloader.loadEnd' ).fire();
2720                 } );
2721         } );
2722
2723         // Attach to window and globally alias
2724         window.mw = window.mediaWiki = mw;
2725 }( jQuery ) );