resources/src/mediawiki.Title/Title.js

   1 /*!
   2  * @author Neil Kandalgaonkar, 2010
   3  * @since 1.18
   4  */
   5
   6 /**
   7  * Parse titles into an object structure. Note that when using the constructor
   8  * directly, passing invalid titles will result in an exception. Use #newFromText to use the
   9  * logic directly and get null for invalid titles which is easier to work with.
  10  *
  11  * Note that in the constructor and #newFromText method, `namespace` is the **default** namespace
  12  * only, and can be overridden by a namespace prefix in `title`. If you do not want this behavior,
  13  * use #makeTitle. Compare:
  14  *
  15  *     new mw.Title( 'Foo', NS_TEMPLATE ).getPrefixedText();                  // => 'Template:Foo'
  16  *     mw.Title.newFromText( 'Foo', NS_TEMPLATE ).getPrefixedText();          // => 'Template:Foo'
  17  *     mw.Title.makeTitle( NS_TEMPLATE, 'Foo' ).getPrefixedText();            // => 'Template:Foo'
  18  *
  19  *     new mw.Title( 'Category:Foo', NS_TEMPLATE ).getPrefixedText();         // => 'Category:Foo'
  20  *     mw.Title.newFromText( 'Category:Foo', NS_TEMPLATE ).getPrefixedText(); // => 'Category:Foo'
  21  *     mw.Title.makeTitle( NS_TEMPLATE, 'Category:Foo' ).getPrefixedText();   // => 'Template:Category:Foo'
  22  *
  23  *     new mw.Title( 'Template:Foo', NS_TEMPLATE ).getPrefixedText();         // => 'Template:Foo'
  24  *     mw.Title.newFromText( 'Template:Foo', NS_TEMPLATE ).getPrefixedText(); // => 'Template:Foo'
  25  *     mw.Title.makeTitle( NS_TEMPLATE, 'Template:Foo' ).getPrefixedText();   // => 'Template:Template:Foo'
  26  *
  27  * @class mw.Title
  28  */
  29
  30 /* Private members */
  31
  32 var
  33         mwString = require( 'mediawiki.String' ),
  34
  35         toUpperMapping = require( './phpCharToUpper.json' ),
  36
  37         namespaceIds = mw.config.get( 'wgNamespaceIds' ),
  38
  39         /**
  40          * @private
  41          * @static
  42          * @property NS_MAIN
  43          */
  44         NS_MAIN = namespaceIds[ '' ],
  45
  46         /**
  47          * @private
  48          * @static
  49          * @property NS_TALK
  50          */
  51         NS_TALK = namespaceIds.talk,
  52
  53         /**
  54          * @private
  55          * @static
  56          * @property NS_SPECIAL
  57          */
  58         NS_SPECIAL = namespaceIds.special,
  59
  60         /**
  61          * @private
  62          * @static
  63          * @property NS_MEDIA
  64          */
  65         NS_MEDIA = namespaceIds.media,
  66
  67         /**
  68          * @private
  69          * @static
  70          * @property NS_FILE
  71          */
  72         NS_FILE = namespaceIds.file,
  73
  74         /**
  75          * @private
  76          * @static
  77          * @property FILENAME_MAX_BYTES
  78          */
  79         FILENAME_MAX_BYTES = 240,
  80
  81         /**
  82          * @private
  83          * @static
  84          * @property TITLE_MAX_BYTES
  85          */
  86         TITLE_MAX_BYTES = 255,
  87
  88         /**
  89          * Get the namespace id from a namespace name (either from the localized, canonical or alias
  90          * name).
  91          *
  92          * Example: On a German wiki this would return 6 for any of 'File', 'Datei', 'Image' or
  93          * even 'Bild'.
  94          *
  95          * @private
  96          * @static
  97          * @method getNsIdByName
  98          * @param {string} ns Namespace name (case insensitive, leading/trailing space ignored)
  99          * @return {number|boolean} Namespace id or boolean false
 100          */
 101         getNsIdByName = function ( ns ) {
 102                 var id;
 103
 104                 // Don't cast non-strings to strings, because null or undefined should not result in
 105                 // returning the id of a potential namespace called "Null:" (e.g. on null.example.org/wiki)
 106                 // Also, toLowerCase throws exception on null/undefined, because it is a String method.
 107                 if ( typeof ns !== 'string' ) {
 108                         return false;
 109                 }
 110                 // TODO: Should just use local var namespaceIds here but it
 111                 // breaks test which modify the config
 112                 id = mw.config.get( 'wgNamespaceIds' )[ ns.toLowerCase() ];
 113                 if ( id === undefined ) {
 114                         return false;
 115                 }
 116                 return id;
 117         },
 118
 119         /**
 120          * @private
 121          * @method getNamespacePrefix_
 122          * @param {number} namespace
 123          * @return {string}
 124          */
 125         getNamespacePrefix = function ( namespace ) {
 126                 return namespace === NS_MAIN ?
 127                         '' :
 128                         ( mw.config.get( 'wgFormattedNamespaces' )[ namespace ].replace( / /g, '_' ) + ':' );
 129         },
 130
 131         rUnderscoreTrim = /^_+|_+$/g,
 132
 133         rSplit = /^(.+?)_*:_*(.*)$/,
 134
 135         // See MediaWikiTitleCodec.php#getTitleInvalidRegex
 136         rInvalid = new RegExp(
 137                 '[^' + mw.config.get( 'wgLegalTitleChars' ) + ']' +
 138                 // URL percent encoding sequences interfere with the ability
 139                 // to round-trip titles -- you can't link to them consistently.
 140                 '|%[\\dA-Fa-f]{2}' +
 141                 // XML/HTML character references produce similar issues.
 142                 '|&[\\dA-Za-z\u0080-\uFFFF]+;' +
 143                 '|&#\\d+;' +
 144                 '|&#x[\\dA-Fa-f]+;'
 145         ),
 146
 147         // From MediaWikiTitleCodec::splitTitleString() in PHP
 148         // Note that this is not equivalent to /\s/, e.g. underscore is included, tab is not included.
 149         rWhitespace = /[ _\u00A0\u1680\u180E\u2000-\u200A\u2028\u2029\u202F\u205F\u3000]+/g,
 150
 151         // From MediaWikiTitleCodec::splitTitleString() in PHP
 152         rUnicodeBidi = /[\u200E\u200F\u202A-\u202E]+/g,
 153
 154         /**
 155          * Slightly modified from Flinfo. Credit goes to Lupo and Flominator.
 156          * @private
 157          * @static
 158          * @property sanitationRules
 159          */
 160         sanitationRules = [
 161                 // "signature"
 162                 {
 163                         pattern: /~{3}/g,
 164                         replace: '',
 165                         generalRule: true
 166                 },
 167                 // control characters
 168                 {
 169                         // eslint-disable-next-line no-control-regex
 170                         pattern: /[\x00-\x1f\x7f]/g,
 171                         replace: '',
 172                         generalRule: true
 173                 },
 174                 // URL encoding (possibly)
 175                 {
 176                         pattern: /%([\dA-Fa-f]{2})/g,
 177                         replace: '% $1',
 178                         generalRule: true
 179                 },
 180                 // HTML-character-entities
 181                 {
 182                         pattern: /&(([\dA-Za-z\x80-\xff]+|#\d+|#x[\dA-Fa-f]+);)/g,
 183                         replace: '& $1',
 184                         generalRule: true
 185                 },
 186                 // slash, colon (not supported by file systems like NTFS/Windows, Mac OS 9 [:], ext4 [/])
 187                 {
 188                         pattern: new RegExp( '[' + mw.config.get( 'wgIllegalFileChars', '' ) + ']', 'g' ),
 189                         replace: '-',
 190                         fileRule: true
 191                 },
 192                 // brackets, greater than
 193                 {
 194                         pattern: /[}\]>]/g,
 195                         replace: ')',
 196                         generalRule: true
 197                 },
 198                 // brackets, lower than
 199                 {
 200                         pattern: /[{[<]/g,
 201                         replace: '(',
 202                         generalRule: true
 203                 },
 204                 // everything that wasn't covered yet
 205                 {
 206                         pattern: new RegExp( rInvalid.source, 'g' ),
 207                         replace: '-',
 208                         generalRule: true
 209                 },
 210                 // directory structures
 211                 {
 212                         pattern: /^(\.|\.\.|\.\/.*|\.\.\/.*|.*\/\.\/.*|.*\/\.\.\/.*|.*\/\.|.*\/\.\.)$/g,
 213                         replace: '',
 214                         generalRule: true
 215                 }
 216         ],
 217
 218         /**
 219          * Internal helper for #constructor and #newFromText.
 220          *
 221          * Based on Title.php#secureAndSplit
 222          *
 223          * @private
 224          * @static
 225          * @method parse
 226          * @param {string} title
 227          * @param {number} [defaultNamespace=NS_MAIN]
 228          * @return {Object|boolean}
 229          */
 230         parse = function ( title, defaultNamespace ) {
 231                 var namespace, m, id, i, fragment;
 232
 233                 namespace = defaultNamespace === undefined ? NS_MAIN : defaultNamespace;
 234
 235                 title = title
 236                         // Strip Unicode bidi override characters
 237                         .replace( rUnicodeBidi, '' )
 238                         // Normalise whitespace to underscores and remove duplicates
 239                         .replace( rWhitespace, '_' )
 240                         // Trim underscores
 241                         .replace( rUnderscoreTrim, '' );
 242
 243                 // Process initial colon
 244                 if ( title !== '' && title[ 0 ] === ':' ) {
 245                         // Initial colon means main namespace instead of specified default
 246                         namespace = NS_MAIN;
 247                         title = title
 248                                 // Strip colon
 249                                 .slice( 1 )
 250                                 // Trim underscores
 251                                 .replace( rUnderscoreTrim, '' );
 252                 }
 253
 254                 if ( title === '' ) {
 255                         return false;
 256                 }
 257
 258                 // Process namespace prefix (if any)
 259                 m = title.match( rSplit );
 260                 if ( m ) {
 261                         id = getNsIdByName( m[ 1 ] );
 262                         if ( id !== false ) {
 263                                 // Ordinary namespace
 264                                 namespace = id;
 265                                 title = m[ 2 ];
 266
 267                                 // For Talk:X pages, make sure X has no "namespace" prefix
 268                                 if ( namespace === NS_TALK && ( m = title.match( rSplit ) ) ) {
 269                                         // Disallow titles like Talk:File:x (subject should roundtrip: talk:file:x -> file:x -> file_talk:x)
 270                                         if ( getNsIdByName( m[ 1 ] ) !== false ) {
 271                                                 return false;
 272                                         }
 273                                 }
 274                         }
 275                 }
 276
 277                 // Process fragment
 278                 i = title.indexOf( '#' );
 279                 if ( i === -1 ) {
 280                         fragment = null;
 281                 } else {
 282                         fragment = title
 283                                 // Get segment starting after the hash
 284                                 .slice( i + 1 )
 285                                 // Convert to text
 286                                 // NB: Must not be trimmed ("Example#_foo" is not the same as "Example#foo")
 287                                 .replace( /_/g, ' ' );
 288
 289                         title = title
 290                                 // Strip hash
 291                                 .slice( 0, i )
 292                                 // Trim underscores, again (strips "_" from "bar" in "Foo_bar_#quux")
 293                                 .replace( rUnderscoreTrim, '' );
 294                 }
 295
 296                 // Reject illegal characters
 297                 if ( rInvalid.test( title ) ) {
 298                         return false;
 299                 }
 300
 301                 // Disallow titles that browsers or servers might resolve as directory navigation
 302                 if (
 303                         title.indexOf( '.' ) !== -1 && (
 304                                 title === '.' || title === '..' ||
 305                                 title.indexOf( './' ) === 0 ||
 306                                 title.indexOf( '../' ) === 0 ||
 307                                 title.indexOf( '/./' ) !== -1 ||
 308                                 title.indexOf( '/../' ) !== -1 ||
 309                                 title.slice( -2 ) === '/.' ||
 310                                 title.slice( -3 ) === '/..'
 311                         )
 312                 ) {
 313                         return false;
 314                 }
 315
 316                 // Disallow magic tilde sequence
 317                 if ( title.indexOf( '~~~' ) !== -1 ) {
 318                         return false;
 319                 }
 320
 321                 // Disallow titles exceeding the TITLE_MAX_BYTES byte size limit (size of underlying database field)
 322                 // Except for special pages, e.g. [[Special:Block/Long name]]
 323                 // Note: The PHP implementation also asserts that even in NS_SPECIAL, the title should
 324                 // be less than 512 bytes.
 325                 if ( namespace !== NS_SPECIAL && mwString.byteLength( title ) > TITLE_MAX_BYTES ) {
 326                         return false;
 327                 }
 328
 329                 // Can't make a link to a namespace alone.
 330                 if ( title === '' && namespace !== NS_MAIN ) {
 331                         return false;
 332                 }
 333
 334                 // Any remaining initial :s are illegal.
 335                 if ( title[ 0 ] === ':' ) {
 336                         return false;
 337                 }
 338
 339                 return {
 340                         namespace: namespace,
 341                         title: title,
 342                         fragment: fragment
 343                 };
 344         },
 345
 346         /**
 347          * Convert db-key to readable text.
 348          *
 349          * @private
 350          * @static
 351          * @method text
 352          * @param {string} s
 353          * @return {string}
 354          */
 355         text = function ( s ) {
 356                 return s.replace( /_/g, ' ' );
 357         },
 358
 359         /**
 360          * Sanitizes a string based on a rule set and a filter
 361          *
 362          * @private
 363          * @static
 364          * @method sanitize
 365          * @param {string} s
 366          * @param {Array} filter
 367          * @return {string}
 368          */
 369         sanitize = function ( s, filter ) {
 370                 var i, ruleLength, rule, m, filterLength,
 371                         rules = sanitationRules;
 372
 373                 for ( i = 0, ruleLength = rules.length; i < ruleLength; ++i ) {
 374                         rule = rules[ i ];
 375                         for ( m = 0, filterLength = filter.length; m < filterLength; ++m ) {
 376                                 if ( rule[ filter[ m ] ] ) {
 377                                         s = s.replace( rule.pattern, rule.replace );
 378                                 }
 379                         }
 380                 }
 381                 return s;
 382         },
 383
 384         /**
 385          * Cuts a string to a specific byte length, assuming UTF-8
 386          * or less, if the last character is a multi-byte one
 387          *
 388          * @private
 389          * @static
 390          * @method trimToByteLength
 391          * @param {string} s
 392          * @param {number} length
 393          * @return {string}
 394          */
 395         trimToByteLength = function ( s, length ) {
 396                 return mwString.trimByteLength( '', s, length ).newVal;
 397         },
 398
 399         /**
 400          * Cuts a file name to a specific byte length
 401          *
 402          * @private
 403          * @static
 404          * @method trimFileNameToByteLength
 405          * @param {string} name without extension
 406          * @param {string} extension file extension
 407          * @return {string} The full name, including extension
 408          */
 409         trimFileNameToByteLength = function ( name, extension ) {
 410                 // There is a special byte limit for file names and ... remember the dot
 411                 return trimToByteLength( name, FILENAME_MAX_BYTES - extension.length - 1 ) + '.' + extension;
 412         };
 413
 414 /**
 415  * @method constructor
 416  * @param {string} title Title of the page. If no second argument given,
 417  *  this will be searched for a namespace
 418  * @param {number} [namespace=NS_MAIN] If given, will used as default namespace for the given title
 419  * @throws {Error} When the title is invalid
 420  */
 421 function Title( title, namespace ) {
 422         var parsed = parse( title, namespace );
 423         if ( !parsed ) {
 424                 throw new Error( 'Unable to parse title' );
 425         }
 426
 427         this.namespace = parsed.namespace;
 428         this.title = parsed.title;
 429         this.fragment = parsed.fragment;
 430 }
 431
 432 /* Static members */
 433
 434 /**
 435  * Constructor for Title objects with a null return instead of an exception for invalid titles.
 436  *
 437  * Note that `namespace` is the **default** namespace only, and can be overridden by a namespace
 438  * prefix in `title`. If you do not want this behavior, use #makeTitle. See #constructor for
 439  * details.
 440  *
 441  * @static
 442  * @param {string} title
 443  * @param {number} [namespace=NS_MAIN] Default namespace
 444  * @return {mw.Title|null} A valid Title object or null if the title is invalid
 445  */
 446 Title.newFromText = function ( title, namespace ) {
 447         var t, parsed = parse( title, namespace );
 448         if ( !parsed ) {
 449                 return null;
 450         }
 451
 452         t = Object.create( Title.prototype );
 453         t.namespace = parsed.namespace;
 454         t.title = parsed.title;
 455         t.fragment = parsed.fragment;
 456
 457         return t;
 458 };
 459
 460 /**
 461  * Constructor for Title objects with predefined namespace.
 462  *
 463  * Unlike #newFromText or #constructor, this function doesn't allow the given `namespace` to be
 464  * overridden by a namespace prefix in `title`. See #constructor for details about this behavior.
 465  *
 466  * The single exception to this is when `namespace` is 0, indicating the main namespace. The
 467  * function behaves like #newFromText in that case.
 468  *
 469  * @static
 470  * @param {number} namespace Namespace to use for the title
 471  * @param {string} title
 472  * @return {mw.Title|null} A valid Title object or null if the title is invalid
 473  */
 474 Title.makeTitle = function ( namespace, title ) {
 475         return mw.Title.newFromText( getNamespacePrefix( namespace ) + title );
 476 };
 477
 478 /**
 479  * Constructor for Title objects from user input altering that input to
 480  * produce a title that MediaWiki will accept as legal
 481  *
 482  * @static
 483  * @param {string} title
 484  * @param {number|Object} [defaultNamespaceOrOptions=NS_MAIN]
 485  *  If given, will used as default namespace for the given title.
 486  *  This method can also be called with two arguments, in which case
 487  *  this becomes options (see below).
 488  * @param {Object} [options] additional options
 489  * @param {boolean} [options.forUploading=true]
 490  *  Makes sure that a file is uploadable under the title returned.
 491  *  There are pages in the file namespace under which file upload is impossible.
 492  *  Automatically assumed if the title is created in the Media namespace.
 493  * @return {mw.Title|null} A valid Title object or null if the input cannot be turned into a valid title
 494  */
 495 Title.newFromUserInput = function ( title, defaultNamespaceOrOptions, options ) {
 496         var namespace, m, id, ext, lastDot,
 497                 defaultNamespace;
 498
 499         // defaultNamespace is optional; check whether options moves up
 500         if ( arguments.length < 3 && typeof defaultNamespace === 'object' ) {
 501                 options = defaultNamespaceOrOptions;
 502         } else {
 503                 defaultNamespace = defaultNamespaceOrOptions;
 504         }
 505
 506         // merge options into defaults
 507         options = $.extend( {
 508                 forUploading: true
 509         }, options );
 510
 511         namespace = defaultNamespace === undefined ? NS_MAIN : defaultNamespace;
 512
 513         // Normalise additional whitespace
 514         title = title.replace( /\s/g, ' ' ).trim();
 515
 516         // Process initial colon
 517         if ( title !== '' && title[ 0 ] === ':' ) {
 518                 // Initial colon means main namespace instead of specified default
 519                 namespace = NS_MAIN;
 520                 title = title
 521                         // Strip colon
 522                         .substr( 1 )
 523                         // Trim underscores
 524                         .replace( rUnderscoreTrim, '' );
 525         }
 526
 527         // Process namespace prefix (if any)
 528         m = title.match( rSplit );
 529         if ( m ) {
 530                 id = getNsIdByName( m[ 1 ] );
 531                 if ( id !== false ) {
 532                         // Ordinary namespace
 533                         namespace = id;
 534                         title = m[ 2 ];
 535                 }
 536         }
 537
 538         if (
 539                 namespace === NS_MEDIA ||
 540                 ( options.forUploading && ( namespace === NS_FILE ) )
 541         ) {
 542                 title = sanitize( title, [ 'generalRule', 'fileRule' ] );
 543
 544                 // Operate on the file extension
 545                 // Although it is possible having spaces between the name and the ".ext" this isn't nice for
 546                 // operating systems hiding file extensions -> strip them later on
 547                 lastDot = title.lastIndexOf( '.' );
 548
 549                 // No or empty file extension
 550                 if ( lastDot === -1 || lastDot >= title.length - 1 ) {
 551                         return null;
 552                 }
 553
 554                 // Get the last part, which is supposed to be the file extension
 555                 ext = title.slice( lastDot + 1 );
 556
 557                 // Remove whitespace of the name part (that without extension)
 558                 title = title.slice( 0, lastDot ).trim();
 559
 560                 // Cut, if too long and append file extension
 561                 title = trimFileNameToByteLength( title, ext );
 562         } else {
 563                 title = sanitize( title, [ 'generalRule' ] );
 564
 565                 // Cut titles exceeding the TITLE_MAX_BYTES byte size limit
 566                 // (size of underlying database field)
 567                 if ( namespace !== NS_SPECIAL ) {
 568                         title = trimToByteLength( title, TITLE_MAX_BYTES );
 569                 }
 570         }
 571
 572         // Any remaining initial :s are illegal.
 573         title = title.replace( /^:+/, '' );
 574
 575         return Title.newFromText( title, namespace );
 576 };
 577
 578 /**
 579  * Sanitizes a file name as supplied by the user, originating in the user's file system
 580  * so it is most likely a valid MediaWiki title and file name after processing.
 581  * Returns null on fatal errors.
 582  *
 583  * @static
 584  * @param {string} uncleanName The unclean file name including file extension but
 585  *   without namespace
 586  * @return {mw.Title|null} A valid Title object or null if the title is invalid
 587  */
 588 Title.newFromFileName = function ( uncleanName ) {
 589         return Title.newFromUserInput( 'File:' + uncleanName, {
 590                 forUploading: true
 591         } );
 592 };
 593
 594 /**
 595  * Get the file title from an image element
 596  *
 597  *     var title = mw.Title.newFromImg( imageNode );
 598  *
 599  * @static
 600  * @param {HTMLElement|jQuery} img The image to use as a base
 601  * @return {mw.Title|null} The file title or null if unsuccessful
 602  */
 603 Title.newFromImg = function ( img ) {
 604         var matches, i, regex, src, decodedSrc,
 605
 606                 // thumb.php-generated thumbnails
 607                 thumbPhpRegex = /thumb\.php/,
 608                 regexes = [
 609                         // Thumbnails
 610                         /\/[\da-f]\/[\da-f]{2}\/([^\s/]+)\/[^\s/]+-[^\s/]*$/,
 611
 612                         // Full size images
 613                         /\/[\da-f]\/[\da-f]{2}\/([^\s/]+)$/,
 614
 615                         // Thumbnails in non-hashed upload directories
 616                         /\/([^\s/]+)\/[^\s/]+-(?:\1|thumbnail)[^\s/]*$/,
 617
 618                         // Full-size images in non-hashed upload directories
 619                         /\/([^\s/]+)$/
 620                 ],
 621
 622                 recount = regexes.length;
 623
 624         src = img.jquery ? img[ 0 ].src : img.src;
 625
 626         if ( thumbPhpRegex.test( src ) ) {
 627                 return mw.Title.newFromText( 'File:' + mw.util.getParamValue( 'f', src ) );
 628         }
 629
 630         decodedSrc = decodeURIComponent( src );
 631
 632         for ( i = 0; i < recount; i++ ) {
 633                 regex = regexes[ i ];
 634                 matches = decodedSrc.match( regex );
 635
 636                 if ( matches && matches[ 1 ] ) {
 637                         return mw.Title.newFromText( 'File:' + matches[ 1 ] );
 638                 }
 639         }
 640
 641         return null;
 642 };
 643
 644 /**
 645  * Check if a given namespace is a talk namespace
 646  *
 647  * See MWNamespace::isTalk in PHP
 648  *
 649  * @param {number} namespaceId Namespace ID
 650  * @return {boolean} Namespace is a talk namespace
 651  */
 652 Title.isTalkNamespace = function ( namespaceId ) {
 653         return !!( namespaceId > NS_MAIN && namespaceId % 2 );
 654 };
 655
 656 /**
 657  * Check if signature buttons should be shown in a given namespace
 658  *
 659  * See MWNamespace::wantSignatures in PHP
 660  *
 661  * @param {number} namespaceId Namespace ID
 662  * @return {boolean} Namespace is a signature namespace
 663  */
 664 Title.wantSignaturesNamespace = function ( namespaceId ) {
 665         return Title.isTalkNamespace( namespaceId ) ||
 666                 mw.config.get( 'wgExtraSignatureNamespaces' ).indexOf( namespaceId ) !== -1;
 667 };
 668
 669 /**
 670  * Whether this title exists on the wiki.
 671  *
 672  * @static
 673  * @param {string|mw.Title} title prefixed db-key name (string) or instance of Title
 674  * @return {boolean|null} Boolean if the information is available, otherwise null
 675  * @throws {Error} If title is not a string or mw.Title
 676  */
 677 Title.exists = function ( title ) {
 678         var match,
 679                 obj = Title.exist.pages;
 680
 681         if ( typeof title === 'string' ) {
 682                 match = obj[ title ];
 683         } else if ( title instanceof Title ) {
 684                 match = obj[ title.toString() ];
 685         } else {
 686                 throw new Error( 'mw.Title.exists: title must be a string or an instance of Title' );
 687         }
 688
 689         if ( typeof match !== 'boolean' ) {
 690                 return null;
 691         }
 692
 693         return match;
 694 };
 695
 696 /**
 697  * Store page existence
 698  *
 699  * @static
 700  * @property {Object} exist
 701  * @property {Object} exist.pages Keyed by title. Boolean true value indicates page does exist.
 702  *
 703  * @property {Function} exist.set The setter function.
 704  *
 705  *  Example to declare existing titles:
 706  *
 707  *     Title.exist.set( ['User:John_Doe', ...] );
 708  *
 709  *  Example to declare titles nonexistent:
 710  *
 711  *     Title.exist.set( ['File:Foo_bar.jpg', ...], false );
 712  *
 713  * @property {string|Array} exist.set.titles Title(s) in strict prefixedDb title form
 714  * @property {boolean} [exist.set.state=true] State of the given titles
 715  * @return {boolean}
 716  */
 717 Title.exist = {
 718         pages: {},
 719
 720         set: function ( titles, state ) {
 721                 var i, len,
 722                         pages = this.pages;
 723
 724                 titles = Array.isArray( titles ) ? titles : [ titles ];
 725                 state = state === undefined ? true : !!state;
 726
 727                 for ( i = 0, len = titles.length; i < len; i++ ) {
 728                         pages[ titles[ i ] ] = state;
 729                 }
 730                 return true;
 731         }
 732 };
 733
 734 /**
 735  * Normalize a file extension to the common form, making it lowercase and checking some synonyms,
 736  * and ensure it's clean. Extensions with non-alphanumeric characters will be discarded.
 737  * Keep in sync with File::normalizeExtension() in PHP.
 738  *
 739  * @param {string} extension File extension (without the leading dot)
 740  * @return {string} File extension in canonical form
 741  */
 742 Title.normalizeExtension = function ( extension ) {
 743         var
 744                 lower = extension.toLowerCase(),
 745                 normalizations = {
 746                         htm: 'html',
 747                         jpeg: 'jpg',
 748                         mpeg: 'mpg',
 749                         tiff: 'tif',
 750                         ogv: 'ogg'
 751                 };
 752         if ( Object.hasOwnProperty.call( normalizations, lower ) ) {
 753                 return normalizations[ lower ];
 754         } else if ( /^[\da-z]+$/.test( lower ) ) {
 755                 return lower;
 756         } else {
 757                 return '';
 758         }
 759 };
 760
 761 /**
 762  * PHP's strtoupper differs from String.toUpperCase in a number of cases (T147646).
 763  *
 764  * @param {string} chr Unicode character
 765  * @return {string} Unicode character, in upper case, according to the same rules as in PHP
 766  */
 767 Title.phpCharToUpper = function ( chr ) {
 768         var mapped = toUpperMapping[ chr ];
 769         return mapped || chr.toUpperCase();
 770 };
 771
 772 /* Public members */
 773
 774 Title.prototype = {
 775         constructor: Title,
 776
 777         /**
 778          * Get the namespace number
 779          *
 780          * Example: 6 for "File:Example_image.svg".
 781          *
 782          * @return {number}
 783          */
 784         getNamespaceId: function () {
 785                 return this.namespace;
 786         },
 787
 788         /**
 789          * Get the namespace prefix (in the content language)
 790          *
 791          * Example: "File:" for "File:Example_image.svg".
 792          * In #NS_MAIN this is '', otherwise namespace name plus ':'
 793          *
 794          * @return {string}
 795          */
 796         getNamespacePrefix: function () {
 797                 return getNamespacePrefix( this.namespace );
 798         },
 799
 800         /**
 801          * Get the page name without extension or namespace prefix
 802          *
 803          * Example: "Example_image" for "File:Example_image.svg".
 804          *
 805          * For the page title (full page name without namespace prefix), see #getMain.
 806          *
 807          * @return {string}
 808          */
 809         getName: function () {
 810                 var ext = this.getExtension();
 811                 if ( ext === null ) {
 812                         return this.getMain();
 813                 }
 814                 return this.getMain().slice( 0, -ext.length - 1 );
 815         },
 816
 817         /**
 818          * Get the page name (transformed by #text)
 819          *
 820          * Example: "Example image" for "File:Example_image.svg".
 821          *
 822          * For the page title (full page name without namespace prefix), see #getMainText.
 823          *
 824          * @return {string}
 825          */
 826         getNameText: function () {
 827                 return text( this.getName() );
 828         },
 829
 830         /**
 831          * Get the extension of the page name (if any)
 832          *
 833          * @return {string|null} Name extension or null if there is none
 834          */
 835         getExtension: function () {
 836                 var lastDot = this.title.lastIndexOf( '.' );
 837                 if ( lastDot === -1 ) {
 838                         return null;
 839                 }
 840                 return this.title.slice( lastDot + 1 ) || null;
 841         },
 842
 843         /**
 844          * Shortcut for appendable string to form the main page name.
 845          *
 846          * Returns a string like ".json", or "" if no extension.
 847          *
 848          * @return {string}
 849          */
 850         getDotExtension: function () {
 851                 var ext = this.getExtension();
 852                 return ext === null ? '' : '.' + ext;
 853         },
 854
 855         /**
 856          * Get the main page name
 857          *
 858          * Example: "Example_image.svg" for "File:Example_image.svg".
 859          *
 860          * @return {string}
 861          */
 862         getMain: function () {
 863                 if (
 864                         mw.config.get( 'wgCaseSensitiveNamespaces' ).indexOf( this.namespace ) !== -1 ||
 865                         !this.title.length
 866                 ) {
 867                         return this.title;
 868                 }
 869                 return mw.Title.phpCharToUpper( this.title[ 0 ] ) + this.title.slice( 1 );
 870         },
 871
 872         /**
 873          * Get the main page name (transformed by #text)
 874          *
 875          * Example: "Example image.svg" for "File:Example_image.svg".
 876          *
 877          * @return {string}
 878          */
 879         getMainText: function () {
 880                 return text( this.getMain() );
 881         },
 882
 883         /**
 884          * Get the full page name
 885          *
 886          * Example: "File:Example_image.svg".
 887          * Most useful for API calls, anything that must identify the "title".
 888          *
 889          * @return {string}
 890          */
 891         getPrefixedDb: function () {
 892                 return this.getNamespacePrefix() + this.getMain();
 893         },
 894
 895         /**
 896          * Get the full page name (transformed by #text)
 897          *
 898          * Example: "File:Example image.svg" for "File:Example_image.svg".
 899          *
 900          * @return {string}
 901          */
 902         getPrefixedText: function () {
 903                 return text( this.getPrefixedDb() );
 904         },
 905
 906         /**
 907          * Get the page name relative to a namespace
 908          *
 909          * Example:
 910          *
 911          * - "Foo:Bar" relative to the Foo namespace becomes "Bar".
 912          * - "Bar" relative to any non-main namespace becomes ":Bar".
 913          * - "Foo:Bar" relative to any namespace other than Foo stays "Foo:Bar".
 914          *
 915          * @param {number} namespace The namespace to be relative to
 916          * @return {string}
 917          */
 918         getRelativeText: function ( namespace ) {
 919                 if ( this.getNamespaceId() === namespace ) {
 920                         return this.getMainText();
 921                 } else if ( this.getNamespaceId() === NS_MAIN ) {
 922                         return ':' + this.getPrefixedText();
 923                 } else {
 924                         return this.getPrefixedText();
 925                 }
 926         },
 927
 928         /**
 929          * Get the fragment (if any).
 930          *
 931          * Note that this method (by design) does not include the hash character and
 932          * the value is not url encoded.
 933          *
 934          * @return {string|null}
 935          */
 936         getFragment: function () {
 937                 return this.fragment;
 938         },
 939
 940         /**
 941          * Get the URL to this title
 942          *
 943          * @see mw.util#getUrl
 944          * @param {Object} [params] A mapping of query parameter names to values,
 945          *     e.g. `{ action: 'edit' }`.
 946          * @return {string}
 947          */
 948         getUrl: function ( params ) {
 949                 var fragment = this.getFragment();
 950                 if ( fragment ) {
 951                         return mw.util.getUrl( this.toString() + '#' + fragment, params );
 952                 } else {
 953                         return mw.util.getUrl( this.toString(), params );
 954                 }
 955         },
 956
 957         /**
 958          * Check if the title is in a talk namespace
 959          *
 960          * @return {boolean} The title is in a talk namespace
 961          */
 962         isTalkPage: function () {
 963                 return Title.isTalkNamespace( this.getNamespaceId() );
 964         },
 965
 966         /**
 967          * Get the title for the associated talk page
 968          *
 969          * @return {mw.Title|null} The title for the associated talk page, null if not available
 970          */
 971         getTalkPage: function () {
 972                 if ( !this.canHaveTalkPage() ) {
 973                         return null;
 974                 }
 975                 return this.isTalkPage() ?
 976                         this :
 977                         Title.makeTitle( this.getNamespaceId() + 1, this.getMainText() );
 978         },
 979
 980         /**
 981          * Get the title for the subject page of a talk page
 982          *
 983          * @return {mw.Title|null} The title for the subject page of a talk page, null if not available
 984          */
 985         getSubjectPage: function () {
 986                 return this.isTalkPage() ?
 987                         Title.makeTitle( this.getNamespaceId() - 1, this.getMainText() ) :
 988                         this;
 989         },
 990
 991         /**
 992          * Check the the title can have an associated talk page
 993          *
 994          * @return {boolean} The title can have an associated talk page
 995          */
 996         canHaveTalkPage: function () {
 997                 return this.getNamespaceId() >= NS_MAIN;
 998         },
 999
1000         /**
1001          * Whether this title exists on the wiki.
1002          *
1003          * @see #static-method-exists
1004          * @return {boolean|null} Boolean if the information is available, otherwise null
1005          */
1006         exists: function () {
1007                 return Title.exists( this );
1008         }
1009 };
1010
1011 /**
1012  * @alias #getPrefixedDb
1013  * @method
1014  */
1015 Title.prototype.toString = Title.prototype.getPrefixedDb;
1016
1017 /**
1018  * @alias #getPrefixedText
1019  * @method
1020  */
1021 Title.prototype.toText = Title.prototype.getPrefixedText;
1022
1023 // Expose
1024 mw.Title = Title;