includes/language/Message.php

   1 <?php
   2 /**
   3  * Fetching and processing of interface messages.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Niklas Laxström
  22  */
  23
  24 use MediaWiki\Logger\LoggerFactory;
  25 use MediaWiki\MediaWikiServices;
  26
  27 /**
  28  * The Message class provides methods which fulfil two basic services:
  29  *  - fetching interface messages
  30  *  - processing messages into a variety of formats
  31  *
  32  * First implemented with MediaWiki 1.17, the Message class is intended to
  33  * replace the old wfMsg* functions that over time grew unusable.
  34  * @see https://www.mediawiki.org/wiki/Manual:Messages_API for equivalences
  35  * between old and new functions.
  36  *
  37  * You should use the wfMessage() global function which acts as a wrapper for
  38  * the Message class. The wrapper let you pass parameters as arguments.
  39  *
  40  * The most basic usage cases would be:
  41  *
  42  * @code
  43  *     // Initialize a Message object using the 'some_key' message key
  44  *     $message = wfMessage( 'some_key' );
  45  *
  46  *     // Using two parameters those values are strings 'value1' and 'value2':
  47  *     $message = wfMessage( 'some_key',
  48  *          'value1', 'value2'
  49  *     );
  50  * @endcode
  51  *
  52  * @section message_global_fn Global function wrapper:
  53  *
  54  * Since wfMessage() returns a Message instance, you can chain its call with
  55  * a method. Some of them return a Message instance too so you can chain them.
  56  * You will find below several examples of wfMessage() usage.
  57  *
  58  * Fetching a message text for interface message:
  59  *
  60  * @code
  61  *    $button = Xml::button(
  62  *         wfMessage( 'submit' )->text()
  63  *    );
  64  * @endcode
  65  *
  66  * A Message instance can be passed parameters after it has been constructed,
  67  * use the params() method to do so:
  68  *
  69  * @code
  70  *     wfMessage( 'welcome-to' )
  71  *         ->params( $wgSitename )
  72  *         ->text();
  73  * @endcode
  74  *
  75  * {{GRAMMAR}} and friends work correctly:
  76  *
  77  * @code
  78  *    wfMessage( 'are-friends',
  79  *        $user, $friend
  80  *    );
  81  *    wfMessage( 'bad-message' )
  82  *         ->rawParams( '<script>...</script>' )
  83  *         ->escaped();
  84  * @endcode
  85  *
  86  * @section message_language Changing language:
  87  *
  88  * Messages can be requested in a different language or in whatever current
  89  * content language is being used. The methods are:
  90  *     - Message->inContentLanguage()
  91  *     - Message->inLanguage()
  92  *
  93  * Sometimes the message text ends up in the database, so content language is
  94  * needed:
  95  *
  96  * @code
  97  *    wfMessage( 'file-log',
  98  *        $user, $filename
  99  *    )->inContentLanguage()->text();
 100  * @endcode
 101  *
 102  * Checking whether a message exists:
 103  *
 104  * @code
 105  *    wfMessage( 'mysterious-message' )->exists()
 106  *    // returns a boolean whether the 'mysterious-message' key exist.
 107  * @endcode
 108  *
 109  * If you want to use a different language:
 110  *
 111  * @code
 112  *    $userLanguage = $user->getOption( 'language' );
 113  *    wfMessage( 'email-header' )
 114  *         ->inLanguage( $userLanguage )
 115  *         ->plain();
 116  * @endcode
 117  *
 118  * @note You can parse the text only in the content or interface languages
 119  *
 120  * @section message_compare_old Comparison with old wfMsg* functions:
 121  *
 122  * Use full parsing:
 123  *
 124  * @code
 125  *     // old style:
 126  *     wfMsgExt( 'key', [ 'parseinline' ], 'apple' );
 127  *     // new style:
 128  *     wfMessage( 'key', 'apple' )->parse();
 129  * @endcode
 130  *
 131  * Parseinline is used because it is more useful when pre-building HTML.
 132  * In normal use it is better to use OutputPage::(add|wrap)WikiMsg.
 133  *
 134  * Places where HTML cannot be used. {{-transformation is done.
 135  * @code
 136  *     // old style:
 137  *     wfMsgExt( 'key', [ 'parsemag' ], 'apple', 'pear' );
 138  *     // new style:
 139  *     wfMessage( 'key', 'apple', 'pear' )->text();
 140  * @endcode
 141  *
 142  * Shortcut for escaping the message too, similar to wfMsgHTML(), but
 143  * parameters are not replaced after escaping by default.
 144  * @code
 145  *     $escaped = wfMessage( 'key' )
 146  *          ->rawParams( 'apple' )
 147  *          ->escaped();
 148  * @endcode
 149  *
 150  * @section message_appendix Appendix:
 151  *
 152  * @todo
 153  * - test, can we have tests?
 154  * - this documentation needs to be extended
 155  *
 156  * @see https://www.mediawiki.org/wiki/WfMessage()
 157  * @see https://www.mediawiki.org/wiki/New_messages_API
 158  * @see https://www.mediawiki.org/wiki/Localisation
 159  *
 160  * @since 1.17
 161  */
 162 class Message implements MessageSpecifier, Serializable {
 163         /** Use message text as-is */
 164         const FORMAT_PLAIN = 'plain';
 165         /** Use normal wikitext -> HTML parsing (the result will be wrapped in a block-level HTML tag) */
 166         const FORMAT_BLOCK_PARSE = 'block-parse';
 167         /** Use normal wikitext -> HTML parsing but strip the block-level wrapper */
 168         const FORMAT_PARSE = 'parse';
 169         /** Transform {{..}} constructs but don't transform to HTML */
 170         const FORMAT_TEXT = 'text';
 171         /** Transform {{..}} constructs, HTML-escape the result */
 172         const FORMAT_ESCAPED = 'escaped';
 173
 174         /**
 175          * Mapping from Message::listParam() types to Language methods.
 176          * @var array
 177          */
 178         protected static $listTypeMap = [
 179                 'comma' => 'commaList',
 180                 'semicolon' => 'semicolonList',
 181                 'pipe' => 'pipeList',
 182                 'text' => 'listToText',
 183         ];
 184
 185         /**
 186          * In which language to get this message. True, which is the default,
 187          * means the current user language, false content language.
 188          *
 189          * @var bool
 190          */
 191         protected $interface = true;
 192
 193         /**
 194          * In which language to get this message. Overrides the $interface setting.
 195          *
 196          * @var Language|bool Explicit language object, or false for user language
 197          */
 198         protected $language = false;
 199
 200         /**
 201          * @var string The message key. If $keysToTry has more than one element,
 202          * this may change to one of the keys to try when fetching the message text.
 203          */
 204         protected $key;
 205
 206         /**
 207          * @var string[] List of keys to try when fetching the message.
 208          */
 209         protected $keysToTry;
 210
 211         /**
 212          * @var array List of parameters which will be substituted into the message.
 213          */
 214         protected $parameters = [];
 215
 216         /**
 217          * @var string
 218          * @deprecated
 219          */
 220         protected $format = 'parse';
 221
 222         /**
 223          * @var bool Whether database can be used.
 224          */
 225         protected $useDatabase = true;
 226
 227         /**
 228          * @var Title Title object to use as context.
 229          */
 230         protected $title = null;
 231
 232         /**
 233          * @var Content Content object representing the message.
 234          */
 235         protected $content = null;
 236
 237         /**
 238          * @var string
 239          */
 240         protected $message;
 241
 242         /**
 243          * @since 1.17
 244          * @param string|string[]|MessageSpecifier $key Message key, or array of
 245          * message keys to try and use the first non-empty message for, or a
 246          * MessageSpecifier to copy from.
 247          * @param array $params Message parameters.
 248          * @param Language|null $language [optional] Language to use (defaults to current user language).
 249          * @throws InvalidArgumentException
 250          */
 251         public function __construct( $key, $params = [], Language $language = null ) {
 252                 if ( $key instanceof MessageSpecifier ) {
 253                         if ( $params ) {
 254                                 throw new InvalidArgumentException(
 255                                         '$params must be empty if $key is a MessageSpecifier'
 256                                 );
 257                         }
 258                         $params = $key->getParams();
 259                         $key = $key->getKey();
 260                 }
 261
 262                 if ( !is_string( $key ) && !is_array( $key ) ) {
 263                         throw new InvalidArgumentException( '$key must be a string or an array' );
 264                 }
 265
 266                 $this->keysToTry = (array)$key;
 267
 268                 if ( empty( $this->keysToTry ) ) {
 269                         throw new InvalidArgumentException( '$key must not be an empty list' );
 270                 }
 271
 272                 $this->key = reset( $this->keysToTry );
 273
 274                 $this->parameters = array_values( $params );
 275                 // User language is only resolved in getLanguage(). This helps preserve the
 276                 // semantic intent of "user language" across serialize() and unserialize().
 277                 $this->language = $language ?: false;
 278         }
 279
 280         /**
 281          * @see Serializable::serialize()
 282          * @since 1.26
 283          * @return string
 284          */
 285         public function serialize() {
 286                 return serialize( [
 287                         'interface' => $this->interface,
 288                         'language' => $this->language ? $this->language->getCode() : false,
 289                         'key' => $this->key,
 290                         'keysToTry' => $this->keysToTry,
 291                         'parameters' => $this->parameters,
 292                         'format' => $this->format,
 293                         'useDatabase' => $this->useDatabase,
 294                         'titlestr' => $this->title ? $this->title->getFullText() : null,
 295                 ] );
 296         }
 297
 298         /**
 299          * @see Serializable::unserialize()
 300          * @since 1.26
 301          * @param string $serialized
 302          */
 303         public function unserialize( $serialized ) {
 304                 $data = unserialize( $serialized );
 305                 if ( !is_array( $data ) ) {
 306                         throw new InvalidArgumentException( __METHOD__ . ': Invalid serialized data' );
 307                 }
 308
 309                 $this->interface = $data['interface'];
 310                 $this->key = $data['key'];
 311                 $this->keysToTry = $data['keysToTry'];
 312                 $this->parameters = $data['parameters'];
 313                 $this->format = $data['format'];
 314                 $this->useDatabase = $data['useDatabase'];
 315                 $this->language = $data['language'] ? Language::factory( $data['language'] ) : false;
 316
 317                 if ( isset( $data['titlestr'] ) ) {
 318                         $this->title = Title::newFromText( $data['titlestr'] );
 319                 } elseif ( isset( $data['title'] ) && $data['title'] instanceof Title ) {
 320                         // Old serializations from before December 2018
 321                         $this->title = $data['title'];
 322                 } else {
 323                         $this->title = null; // Explicit for sanity
 324                 }
 325         }
 326
 327         /**
 328          * @since 1.24
 329          *
 330          * @return bool True if this is a multi-key message, that is, if the key provided to the
 331          * constructor was a fallback list of keys to try.
 332          */
 333         public function isMultiKey() {
 334                 return count( $this->keysToTry ) > 1;
 335         }
 336
 337         /**
 338          * @since 1.24
 339          *
 340          * @return string[] The list of keys to try when fetching the message text,
 341          * in order of preference.
 342          */
 343         public function getKeysToTry() {
 344                 return $this->keysToTry;
 345         }
 346
 347         /**
 348          * Returns the message key.
 349          *
 350          * If a list of multiple possible keys was supplied to the constructor, this method may
 351          * return any of these keys. After the message has been fetched, this method will return
 352          * the key that was actually used to fetch the message.
 353          *
 354          * @since 1.21
 355          *
 356          * @return string
 357          */
 358         public function getKey() {
 359                 return $this->key;
 360         }
 361
 362         /**
 363          * Returns the message parameters.
 364          *
 365          * @since 1.21
 366          *
 367          * @return array
 368          */
 369         public function getParams() {
 370                 return $this->parameters;
 371         }
 372
 373         /**
 374          * Returns the message format.
 375          *
 376          * @since 1.21
 377          *
 378          * @return string
 379          * @deprecated since 1.29 formatting is not stateful
 380          */
 381         public function getFormat() {
 382                 wfDeprecated( __METHOD__, '1.29' );
 383                 return $this->format;
 384         }
 385
 386         /**
 387          * Returns the Language of the Message.
 388          *
 389          * @since 1.23
 390          *
 391          * @return Language
 392          */
 393         public function getLanguage() {
 394                 // Defaults to false which means current user language
 395                 return $this->language ?: RequestContext::getMain()->getLanguage();
 396         }
 397
 398         /**
 399          * Factory function that is just wrapper for the real constructor. It is
 400          * intended to be used instead of the real constructor, because it allows
 401          * chaining method calls, while new objects don't.
 402          *
 403          * @since 1.17
 404          *
 405          * @param string|string[]|MessageSpecifier $key
 406          * @param mixed $param,... Parameters as strings.
 407          *
 408          * @return Message
 409          */
 410         public static function newFromKey( $key /*...*/ ) {
 411                 $params = func_get_args();
 412                 array_shift( $params );
 413                 return new self( $key, $params );
 414         }
 415
 416         /**
 417          * Transform a MessageSpecifier or a primitive value used interchangeably with
 418          * specifiers (a message key string, or a key + params array) into a proper Message.
 419          *
 420          * Also accepts a MessageSpecifier inside an array: that's not considered a valid format
 421          * but is an easy error to make due to how StatusValue stores messages internally.
 422          * Further array elements are ignored in that case.
 423          *
 424          * @param string|array|MessageSpecifier $value
 425          * @return Message
 426          * @throws InvalidArgumentException
 427          * @since 1.27
 428          */
 429         public static function newFromSpecifier( $value ) {
 430                 $params = [];
 431                 if ( is_array( $value ) ) {
 432                         $params = $value;
 433                         $value = array_shift( $params );
 434                 }
 435
 436                 if ( $value instanceof Message ) { // Message, RawMessage, ApiMessage, etc
 437                         $message = clone $value;
 438                 } elseif ( $value instanceof MessageSpecifier ) {
 439                         $message = new Message( $value );
 440                 } elseif ( is_string( $value ) ) {
 441                         $message = new Message( $value, $params );
 442                 } else {
 443                         throw new InvalidArgumentException( __METHOD__ . ': invalid argument type '
 444                                 . gettype( $value ) );
 445                 }
 446
 447                 return $message;
 448         }
 449
 450         /**
 451          * Factory function accepting multiple message keys and returning a message instance
 452          * for the first message which is non-empty. If all messages are empty then an
 453          * instance of the first message key is returned.
 454          *
 455          * @since 1.18
 456          *
 457          * @param string|string[] $keys,... Message keys, or first argument as an array of all the
 458          * message keys.
 459          *
 460          * @return Message
 461          */
 462         public static function newFallbackSequence( /*...*/ ) {
 463                 $keys = func_get_args();
 464                 if ( func_num_args() == 1 ) {
 465                         if ( is_array( $keys[0] ) ) {
 466                                 // Allow an array to be passed as the first argument instead
 467                                 $keys = array_values( $keys[0] );
 468                         } else {
 469                                 // Optimize a single string to not need special fallback handling
 470                                 $keys = $keys[0];
 471                         }
 472                 }
 473                 return new self( $keys );
 474         }
 475
 476         /**
 477          * Get a title object for a mediawiki message, where it can be found in the mediawiki namespace.
 478          * The title will be for the current language, if the message key is in
 479          * $wgForceUIMsgAsContentMsg it will be append with the language code (except content
 480          * language), because Message::inContentLanguage will also return in user language.
 481          *
 482          * @see $wgForceUIMsgAsContentMsg
 483          * @return Title
 484          * @since 1.26
 485          */
 486         public function getTitle() {
 487                 global $wgForceUIMsgAsContentMsg;
 488
 489                 $contLang = MediaWikiServices::getInstance()->getContentLanguage();
 490                 $lang = $this->getLanguage();
 491                 $title = $this->key;
 492                 if (
 493                         !$lang->equals( $contLang )
 494                         && in_array( $this->key, (array)$wgForceUIMsgAsContentMsg )
 495                 ) {
 496                         $title .= '/' . $lang->getCode();
 497                 }
 498
 499                 return Title::makeTitle(
 500                         NS_MEDIAWIKI, $contLang->ucfirst( strtr( $title, ' ', '_' ) ) );
 501         }
 502
 503         /**
 504          * Adds parameters to the parameter list of this message.
 505          *
 506          * @since 1.17
 507          *
 508          * @param mixed $args,... Parameters as strings or arrays from
 509          *  Message::numParam() and the like, or a single array of parameters.
 510          *
 511          * @return Message $this
 512          */
 513         public function params( /*...*/ ) {
 514                 $args = func_get_args();
 515
 516                 // If $args has only one entry and it's an array, then it's either a
 517                 // non-varargs call or it happens to be a call with just a single
 518                 // "special" parameter. Since the "special" parameters don't have any
 519                 // numeric keys, we'll test that to differentiate the cases.
 520                 if ( count( $args ) === 1 && isset( $args[0] ) && is_array( $args[0] ) ) {
 521                         if ( $args[0] === [] ) {
 522                                 $args = [];
 523                         } else {
 524                                 foreach ( $args[0] as $key => $value ) {
 525                                         if ( is_int( $key ) ) {
 526                                                 $args = $args[0];
 527                                                 break;
 528                                         }
 529                                 }
 530                         }
 531                 }
 532
 533                 $this->parameters = array_merge( $this->parameters, array_values( $args ) );
 534                 return $this;
 535         }
 536
 537         /**
 538          * Add parameters that are substituted after parsing or escaping.
 539          * In other words the parsing process cannot access the contents
 540          * of this type of parameter, and you need to make sure it is
 541          * sanitized beforehand.  The parser will see "$n", instead.
 542          *
 543          * @since 1.17
 544          *
 545          * @param mixed $params,... Raw parameters as strings, or a single argument that is
 546          * an array of raw parameters.
 547          *
 548          * @return Message $this
 549          */
 550         public function rawParams( /*...*/ ) {
 551                 $params = func_get_args();
 552                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 553                         $params = $params[0];
 554                 }
 555                 foreach ( $params as $param ) {
 556                         $this->parameters[] = self::rawParam( $param );
 557                 }
 558                 return $this;
 559         }
 560
 561         /**
 562          * Add parameters that are numeric and will be passed through
 563          * Language::formatNum before substitution
 564          *
 565          * @since 1.18
 566          *
 567          * @param mixed $param,... Numeric parameters, or a single argument that is
 568          * an array of numeric parameters.
 569          *
 570          * @return Message $this
 571          */
 572         public function numParams( /*...*/ ) {
 573                 $params = func_get_args();
 574                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 575                         $params = $params[0];
 576                 }
 577                 foreach ( $params as $param ) {
 578                         $this->parameters[] = self::numParam( $param );
 579                 }
 580                 return $this;
 581         }
 582
 583         /**
 584          * Add parameters that are durations of time and will be passed through
 585          * Language::formatDuration before substitution
 586          *
 587          * @since 1.22
 588          *
 589          * @param int|int[] $param,... Duration parameters, or a single argument that is
 590          * an array of duration parameters.
 591          *
 592          * @return Message $this
 593          */
 594         public function durationParams( /*...*/ ) {
 595                 $params = func_get_args();
 596                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 597                         $params = $params[0];
 598                 }
 599                 foreach ( $params as $param ) {
 600                         $this->parameters[] = self::durationParam( $param );
 601                 }
 602                 return $this;
 603         }
 604
 605         /**
 606          * Add parameters that are expiration times and will be passed through
 607          * Language::formatExpiry before substitution
 608          *
 609          * @since 1.22
 610          *
 611          * @param string|string[] $param,... Expiry parameters, or a single argument that is
 612          * an array of expiry parameters.
 613          *
 614          * @return Message $this
 615          */
 616         public function expiryParams( /*...*/ ) {
 617                 $params = func_get_args();
 618                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 619                         $params = $params[0];
 620                 }
 621                 foreach ( $params as $param ) {
 622                         $this->parameters[] = self::expiryParam( $param );
 623                 }
 624                 return $this;
 625         }
 626
 627         /**
 628          * Add parameters that are time periods and will be passed through
 629          * Language::formatTimePeriod before substitution
 630          *
 631          * @since 1.22
 632          *
 633          * @param int|int[] $param,... Time period parameters, or a single argument that is
 634          * an array of time period parameters.
 635          *
 636          * @return Message $this
 637          */
 638         public function timeperiodParams( /*...*/ ) {
 639                 $params = func_get_args();
 640                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 641                         $params = $params[0];
 642                 }
 643                 foreach ( $params as $param ) {
 644                         $this->parameters[] = self::timeperiodParam( $param );
 645                 }
 646                 return $this;
 647         }
 648
 649         /**
 650          * Add parameters that are file sizes and will be passed through
 651          * Language::formatSize before substitution
 652          *
 653          * @since 1.22
 654          *
 655          * @param int|int[] $param,... Size parameters, or a single argument that is
 656          * an array of size parameters.
 657          *
 658          * @return Message $this
 659          */
 660         public function sizeParams( /*...*/ ) {
 661                 $params = func_get_args();
 662                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 663                         $params = $params[0];
 664                 }
 665                 foreach ( $params as $param ) {
 666                         $this->parameters[] = self::sizeParam( $param );
 667                 }
 668                 return $this;
 669         }
 670
 671         /**
 672          * Add parameters that are bitrates and will be passed through
 673          * Language::formatBitrate before substitution
 674          *
 675          * @since 1.22
 676          *
 677          * @param int|int[] $param,... Bit rate parameters, or a single argument that is
 678          * an array of bit rate parameters.
 679          *
 680          * @return Message $this
 681          */
 682         public function bitrateParams( /*...*/ ) {
 683                 $params = func_get_args();
 684                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 685                         $params = $params[0];
 686                 }
 687                 foreach ( $params as $param ) {
 688                         $this->parameters[] = self::bitrateParam( $param );
 689                 }
 690                 return $this;
 691         }
 692
 693         /**
 694          * Add parameters that are plaintext and will be passed through without
 695          * the content being evaluated.  Plaintext parameters are not valid as
 696          * arguments to parser functions. This differs from self::rawParams in
 697          * that the Message class handles escaping to match the output format.
 698          *
 699          * @since 1.25
 700          *
 701          * @param string|string[] $param,... plaintext parameters, or a single argument that is
 702          * an array of plaintext parameters.
 703          *
 704          * @return Message $this
 705          */
 706         public function plaintextParams( /*...*/ ) {
 707                 $params = func_get_args();
 708                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 709                         $params = $params[0];
 710                 }
 711                 foreach ( $params as $param ) {
 712                         $this->parameters[] = self::plaintextParam( $param );
 713                 }
 714                 return $this;
 715         }
 716
 717         /**
 718          * Set the language and the title from a context object
 719          *
 720          * @since 1.19
 721          *
 722          * @param IContextSource $context
 723          *
 724          * @return Message $this
 725          */
 726         public function setContext( IContextSource $context ) {
 727                 $this->inLanguage( $context->getLanguage() );
 728                 $this->title( $context->getTitle() );
 729                 $this->interface = true;
 730
 731                 return $this;
 732         }
 733
 734         /**
 735          * Request the message in any language that is supported.
 736          *
 737          * As a side effect interface message status is unconditionally
 738          * turned off.
 739          *
 740          * @since 1.17
 741          * @param Language|string $lang Language code or Language object.
 742          * @return Message $this
 743          * @throws MWException
 744          */
 745         public function inLanguage( $lang ) {
 746                 $previousLanguage = $this->language;
 747
 748                 if ( $lang instanceof Language ) {
 749                         $this->language = $lang;
 750                 } elseif ( is_string( $lang ) ) {
 751                         if ( !$this->language instanceof Language || $this->language->getCode() != $lang ) {
 752                                 $this->language = Language::factory( $lang );
 753                         }
 754                 } elseif ( $lang instanceof StubUserLang ) {
 755                         $this->language = false;
 756                 } else {
 757                         $type = gettype( $lang );
 758                         throw new MWException( __METHOD__ . " must be "
 759                                 . "passed a String or Language object; $type given"
 760                         );
 761                 }
 762
 763                 if ( $this->language !== $previousLanguage ) {
 764                         // The language has changed. Clear the message cache.
 765                         $this->message = null;
 766                 }
 767                 $this->interface = false;
 768                 return $this;
 769         }
 770
 771         /**
 772          * Request the message in the wiki's content language,
 773          * unless it is disabled for this message.
 774          *
 775          * @since 1.17
 776          * @see $wgForceUIMsgAsContentMsg
 777          *
 778          * @return Message $this
 779          */
 780         public function inContentLanguage() {
 781                 global $wgForceUIMsgAsContentMsg;
 782                 if ( in_array( $this->key, (array)$wgForceUIMsgAsContentMsg ) ) {
 783                         return $this;
 784                 }
 785
 786                 $this->inLanguage( MediaWikiServices::getInstance()->getContentLanguage() );
 787                 return $this;
 788         }
 789
 790         /**
 791          * Allows manipulating the interface message flag directly.
 792          * Can be used to restore the flag after setting a language.
 793          *
 794          * @since 1.20
 795          *
 796          * @param bool $interface
 797          *
 798          * @return Message $this
 799          */
 800         public function setInterfaceMessageFlag( $interface ) {
 801                 $this->interface = (bool)$interface;
 802                 return $this;
 803         }
 804
 805         /**
 806          * Enable or disable database use.
 807          *
 808          * @since 1.17
 809          *
 810          * @param bool $useDatabase
 811          *
 812          * @return Message $this
 813          */
 814         public function useDatabase( $useDatabase ) {
 815                 $this->useDatabase = (bool)$useDatabase;
 816                 $this->message = null;
 817                 return $this;
 818         }
 819
 820         /**
 821          * Set the Title object to use as context when transforming the message
 822          *
 823          * @since 1.18
 824          *
 825          * @param Title $title
 826          *
 827          * @return Message $this
 828          */
 829         public function title( $title ) {
 830                 $this->title = $title;
 831                 return $this;
 832         }
 833
 834         /**
 835          * Returns the message as a Content object.
 836          *
 837          * @return Content
 838          */
 839         public function content() {
 840                 if ( !$this->content ) {
 841                         $this->content = new MessageContent( $this );
 842                 }
 843
 844                 return $this->content;
 845         }
 846
 847         /**
 848          * Returns the message parsed from wikitext to HTML.
 849          *
 850          * @since 1.17
 851          *
 852          * @param string|null $format One of the FORMAT_* constants. Null means use whatever was used
 853          *   the last time (this is for B/C and should be avoided).
 854          *
 855          * @return string HTML
 856          * @suppress SecurityCheck-DoubleEscaped phan false positive
 857          */
 858         public function toString( $format = null ) {
 859                 if ( $format === null ) {
 860                         $ex = new LogicException( __METHOD__ . ' using implicit format: ' . $this->format );
 861                         LoggerFactory::getInstance( 'message-format' )->warning(
 862                                 $ex->getMessage(), [ 'exception' => $ex, 'format' => $this->format, 'key' => $this->key ] );
 863                         $format = $this->format;
 864                 }
 865                 $string = $this->fetchMessage();
 866
 867                 if ( $string === false ) {
 868                         // Err on the side of safety, ensure that the output
 869                         // is always html safe in the event the message key is
 870                         // missing, since in that case its highly likely the
 871                         // message key is user-controlled.
 872                         // '⧼' is used instead of '<' to side-step any
 873                         // double-escaping issues.
 874                         // (Keep synchronised with mw.Message#toString in JS.)
 875                         return '⧼' . htmlspecialchars( $this->key ) . '⧽';
 876                 }
 877
 878                 # Replace $* with a list of parameters for &uselang=qqx.
 879                 if ( strpos( $string, '$*' ) !== false ) {
 880                         $paramlist = '';
 881                         if ( $this->parameters !== [] ) {
 882                                 $paramlist = ': $' . implode( ', $', range( 1, count( $this->parameters ) ) );
 883                         }
 884                         $string = str_replace( '$*', $paramlist, $string );
 885                 }
 886
 887                 # Replace parameters before text parsing
 888                 $string = $this->replaceParameters( $string, 'before', $format );
 889
 890                 # Maybe transform using the full parser
 891                 if ( $format === self::FORMAT_PARSE ) {
 892                         $string = $this->parseText( $string );
 893                         $string = Parser::stripOuterParagraph( $string );
 894                 } elseif ( $format === self::FORMAT_BLOCK_PARSE ) {
 895                         $string = $this->parseText( $string );
 896                 } elseif ( $format === self::FORMAT_TEXT ) {
 897                         $string = $this->transformText( $string );
 898                 } elseif ( $format === self::FORMAT_ESCAPED ) {
 899                         $string = $this->transformText( $string );
 900                         $string = htmlspecialchars( $string, ENT_QUOTES, 'UTF-8', false );
 901                 }
 902
 903                 # Raw parameter replacement
 904                 $string = $this->replaceParameters( $string, 'after', $format );
 905
 906                 return $string;
 907         }
 908
 909         /**
 910          * Magic method implementation of the above (for PHP >= 5.2.0), so we can do, eg:
 911          *     $foo = new Message( $key );
 912          *     $string = "<abbr>$foo</abbr>";
 913          *
 914          * @since 1.18
 915          *
 916          * @return string
 917          */
 918         public function __toString() {
 919                 // PHP doesn't allow __toString to throw exceptions and will
 920                 // trigger a fatal error if it does. So, catch any exceptions.
 921
 922                 try {
 923                         return $this->toString( self::FORMAT_PARSE );
 924                 } catch ( Exception $ex ) {
 925                         try {
 926                                 trigger_error( "Exception caught in " . __METHOD__ . " (message " . $this->key . "): "
 927                                         . $ex, E_USER_WARNING );
 928                         } catch ( Exception $ex ) {
 929                                 // Doh! Cause a fatal error after all?
 930                         }
 931
 932                         return '⧼' . htmlspecialchars( $this->key ) . '⧽';
 933                 }
 934         }
 935
 936         /**
 937          * Fully parse the text from wikitext to HTML.
 938          *
 939          * @since 1.17
 940          *
 941          * @return string Parsed HTML.
 942          */
 943         public function parse() {
 944                 $this->format = self::FORMAT_PARSE;
 945                 return $this->toString( self::FORMAT_PARSE );
 946         }
 947
 948         /**
 949          * Returns the message text. {{-transformation is done.
 950          *
 951          * @since 1.17
 952          *
 953          * @return string Unescaped message text.
 954          */
 955         public function text() {
 956                 $this->format = self::FORMAT_TEXT;
 957                 return $this->toString( self::FORMAT_TEXT );
 958         }
 959
 960         /**
 961          * Returns the message text as-is, only parameters are substituted.
 962          *
 963          * @since 1.17
 964          *
 965          * @return string Unescaped untransformed message text.
 966          */
 967         public function plain() {
 968                 $this->format = self::FORMAT_PLAIN;
 969                 return $this->toString( self::FORMAT_PLAIN );
 970         }
 971
 972         /**
 973          * Returns the parsed message text which is always surrounded by a block element.
 974          *
 975          * @since 1.17
 976          *
 977          * @return string HTML
 978          */
 979         public function parseAsBlock() {
 980                 $this->format = self::FORMAT_BLOCK_PARSE;
 981                 return $this->toString( self::FORMAT_BLOCK_PARSE );
 982         }
 983
 984         /**
 985          * Returns the message text. {{-transformation is done and the result
 986          * is escaped excluding any raw parameters.
 987          *
 988          * @since 1.17
 989          *
 990          * @return string Escaped message text.
 991          */
 992         public function escaped() {
 993                 $this->format = self::FORMAT_ESCAPED;
 994                 return $this->toString( self::FORMAT_ESCAPED );
 995         }
 996
 997         /**
 998          * Check whether a message key has been defined currently.
 999          *
1000          * @since 1.17
1001          *
1002          * @return bool
1003          */
1004         public function exists() {
1005                 return $this->fetchMessage() !== false;
1006         }
1007
1008         /**
1009          * Check whether a message does not exist, or is an empty string
1010          *
1011          * @since 1.18
1012          * @todo FIXME: Merge with isDisabled()?
1013          *
1014          * @return bool
1015          */
1016         public function isBlank() {
1017                 $message = $this->fetchMessage();
1018                 return $message === false || $message === '';
1019         }
1020
1021         /**
1022          * Check whether a message does not exist, is an empty string, or is "-".
1023          *
1024          * @since 1.18
1025          *
1026          * @return bool
1027          */
1028         public function isDisabled() {
1029                 $message = $this->fetchMessage();
1030                 return $message === false || $message === '' || $message === '-';
1031         }
1032
1033         /**
1034          * @since 1.17
1035          *
1036          * @param mixed $raw
1037          *
1038          * @return array Array with a single "raw" key.
1039          */
1040         public static function rawParam( $raw ) {
1041                 return [ 'raw' => $raw ];
1042         }
1043
1044         /**
1045          * @since 1.18
1046          *
1047          * @param mixed $num
1048          *
1049          * @return array Array with a single "num" key.
1050          */
1051         public static function numParam( $num ) {
1052                 return [ 'num' => $num ];
1053         }
1054
1055         /**
1056          * @since 1.22
1057          *
1058          * @param int $duration
1059          *
1060          * @return int[] Array with a single "duration" key.
1061          */
1062         public static function durationParam( $duration ) {
1063                 return [ 'duration' => $duration ];
1064         }
1065
1066         /**
1067          * @since 1.22
1068          *
1069          * @param string $expiry
1070          *
1071          * @return string[] Array with a single "expiry" key.
1072          */
1073         public static function expiryParam( $expiry ) {
1074                 return [ 'expiry' => $expiry ];
1075         }
1076
1077         /**
1078          * @since 1.22
1079          *
1080          * @param int $period
1081          *
1082          * @return int[] Array with a single "period" key.
1083          */
1084         public static function timeperiodParam( $period ) {
1085                 return [ 'period' => $period ];
1086         }
1087
1088         /**
1089          * @since 1.22
1090          *
1091          * @param int $size
1092          *
1093          * @return int[] Array with a single "size" key.
1094          */
1095         public static function sizeParam( $size ) {
1096                 return [ 'size' => $size ];
1097         }
1098
1099         /**
1100          * @since 1.22
1101          *
1102          * @param int $bitrate
1103          *
1104          * @return int[] Array with a single "bitrate" key.
1105          */
1106         public static function bitrateParam( $bitrate ) {
1107                 return [ 'bitrate' => $bitrate ];
1108         }
1109
1110         /**
1111          * @since 1.25
1112          *
1113          * @param string $plaintext
1114          *
1115          * @return string[] Array with a single "plaintext" key.
1116          */
1117         public static function plaintextParam( $plaintext ) {
1118                 return [ 'plaintext' => $plaintext ];
1119         }
1120
1121         /**
1122          * @since 1.29
1123          *
1124          * @param array $list
1125          * @param string $type 'comma', 'semicolon', 'pipe', 'text'
1126          * @return array Array with "list" and "type" keys.
1127          */
1128         public static function listParam( array $list, $type = 'text' ) {
1129                 if ( !isset( self::$listTypeMap[$type] ) ) {
1130                         throw new InvalidArgumentException(
1131                                 "Invalid type '$type'. Known types are: " . implode( ', ', array_keys( self::$listTypeMap ) )
1132                         );
1133                 }
1134                 return [ 'list' => $list, 'type' => $type ];
1135         }
1136
1137         /**
1138          * Substitutes any parameters into the message text.
1139          *
1140          * @since 1.17
1141          *
1142          * @param string $message The message text.
1143          * @param string $type Either "before" or "after".
1144          * @param string $format One of the FORMAT_* constants.
1145          *
1146          * @return string
1147          */
1148         protected function replaceParameters( $message, $type, $format ) {
1149                 // A temporary marker for $1 parameters that is only valid
1150                 // in non-attribute contexts. However if the entire message is escaped
1151                 // then we don't want to use it because it will be mangled in all contexts
1152                 // and its unnessary as ->escaped() messages aren't html.
1153                 $marker = $format === self::FORMAT_ESCAPED ? '$' : '$\'"';
1154                 $replacementKeys = [];
1155                 foreach ( $this->parameters as $n => $param ) {
1156                         list( $paramType, $value ) = $this->extractParam( $param, $format );
1157                         if ( $type === 'before' ) {
1158                                 if ( $paramType === 'before' ) {
1159                                         $replacementKeys['$' . ( $n + 1 )] = $value;
1160                                 } else /* $paramType === 'after' */ {
1161                                         // To protect against XSS from replacing parameters
1162                                         // inside html attributes, we convert $1 to $'"1.
1163                                         // In the event that one of the parameters ends up
1164                                         // in an attribute, either the ' or the " will be
1165                                         // escaped, breaking the replacement and avoiding XSS.
1166                                         $replacementKeys['$' . ( $n + 1 )] = $marker . ( $n + 1 );
1167                                 }
1168                         } elseif ( $paramType === 'after' ) {
1169                                 $replacementKeys[$marker . ( $n + 1 )] = $value;
1170                         }
1171                 }
1172                 return strtr( $message, $replacementKeys );
1173         }
1174
1175         /**
1176          * Extracts the parameter type and preprocessed the value if needed.
1177          *
1178          * @since 1.18
1179          *
1180          * @param mixed $param Parameter as defined in this class.
1181          * @param string $format One of the FORMAT_* constants.
1182          *
1183          * @return array Array with the parameter type (either "before" or "after") and the value.
1184          */
1185         protected function extractParam( $param, $format ) {
1186                 if ( is_array( $param ) ) {
1187                         if ( isset( $param['raw'] ) ) {
1188                                 return [ 'after', $param['raw'] ];
1189                         } elseif ( isset( $param['num'] ) ) {
1190                                 // Replace number params always in before step for now.
1191                                 // No support for combined raw and num params
1192                                 return [ 'before', $this->getLanguage()->formatNum( $param['num'] ) ];
1193                         } elseif ( isset( $param['duration'] ) ) {
1194                                 return [ 'before', $this->getLanguage()->formatDuration( $param['duration'] ) ];
1195                         } elseif ( isset( $param['expiry'] ) ) {
1196                                 return [ 'before', $this->getLanguage()->formatExpiry( $param['expiry'] ) ];
1197                         } elseif ( isset( $param['period'] ) ) {
1198                                 return [ 'before', $this->getLanguage()->formatTimePeriod( $param['period'] ) ];
1199                         } elseif ( isset( $param['size'] ) ) {
1200                                 return [ 'before', $this->getLanguage()->formatSize( $param['size'] ) ];
1201                         } elseif ( isset( $param['bitrate'] ) ) {
1202                                 return [ 'before', $this->getLanguage()->formatBitrate( $param['bitrate'] ) ];
1203                         } elseif ( isset( $param['plaintext'] ) ) {
1204                                 return [ 'after', $this->formatPlaintext( $param['plaintext'], $format ) ];
1205                         } elseif ( isset( $param['list'] ) ) {
1206                                 return $this->formatListParam( $param['list'], $param['type'], $format );
1207                         } else {
1208                                 if ( !is_scalar( $param ) ) {
1209                                         $param = serialize( $param );
1210                                 }
1211                                 LoggerFactory::getInstance( 'Bug58676' )->warning(
1212                                         'Invalid parameter for message "{msgkey}": {param}',
1213                                         [
1214                                                 'exception' => new Exception,
1215                                                 'msgkey' => $this->getKey(),
1216                                                 'param' => htmlspecialchars( $param ),
1217                                         ]
1218                                 );
1219
1220                                 return [ 'before', '[INVALID]' ];
1221                         }
1222                 } elseif ( $param instanceof Message ) {
1223                         // Match language, flags, etc. to the current message.
1224                         $msg = clone $param;
1225                         if ( $msg->language !== $this->language || $msg->useDatabase !== $this->useDatabase ) {
1226                                 // Cache depends on these parameters
1227                                 $msg->message = null;
1228                         }
1229                         $msg->interface = $this->interface;
1230                         $msg->language = $this->language;
1231                         $msg->useDatabase = $this->useDatabase;
1232                         $msg->title = $this->title;
1233
1234                         // DWIM
1235                         if ( $format === 'block-parse' ) {
1236                                 $format = 'parse';
1237                         }
1238                         $msg->format = $format;
1239
1240                         // Message objects should not be before parameters because
1241                         // then they'll get double escaped. If the message needs to be
1242                         // escaped, it'll happen right here when we call toString().
1243                         return [ 'after', $msg->toString( $format ) ];
1244                 } else {
1245                         return [ 'before', $param ];
1246                 }
1247         }
1248
1249         /**
1250          * Wrapper for what ever method we use to parse wikitext.
1251          *
1252          * @since 1.17
1253          *
1254          * @param string $string Wikitext message contents.
1255          *
1256          * @return string Wikitext parsed into HTML.
1257          */
1258         protected function parseText( $string ) {
1259                 $out = MessageCache::singleton()->parse(
1260                         $string,
1261                         $this->title,
1262                         /*linestart*/true,
1263                         $this->interface,
1264                         $this->getLanguage()
1265                 );
1266
1267                 return $out instanceof ParserOutput
1268                         ? $out->getText( [
1269                                 'enableSectionEditLinks' => false,
1270                                 // Wrapping messages in an extra <div> is probably not expected. If
1271                                 // they're outside the content area they probably shouldn't be
1272                                 // targeted by CSS that's targeting the parser output, and if
1273                                 // they're inside they already are from the outer div.
1274                                 'unwrap' => true,
1275                         ] )
1276                         : $out;
1277         }
1278
1279         /**
1280          * Wrapper for what ever method we use to {{-transform wikitext.
1281          *
1282          * @since 1.17
1283          *
1284          * @param string $string Wikitext message contents.
1285          *
1286          * @return string Wikitext with {{-constructs replaced with their values.
1287          */
1288         protected function transformText( $string ) {
1289                 return MessageCache::singleton()->transform(
1290                         $string,
1291                         $this->interface,
1292                         $this->getLanguage(),
1293                         $this->title
1294                 );
1295         }
1296
1297         /**
1298          * Wrapper for what ever method we use to get message contents.
1299          *
1300          * @since 1.17
1301          *
1302          * @return string
1303          * @throws MWException If message key array is empty.
1304          */
1305         protected function fetchMessage() {
1306                 if ( $this->message === null ) {
1307                         $cache = MessageCache::singleton();
1308
1309                         foreach ( $this->keysToTry as $key ) {
1310                                 $message = $cache->get( $key, $this->useDatabase, $this->getLanguage() );
1311                                 if ( $message !== false && $message !== '' ) {
1312                                         break;
1313                                 }
1314                         }
1315
1316                         // NOTE: The constructor makes sure keysToTry isn't empty,
1317                         //       so we know that $key and $message are initialized.
1318                         $this->key = $key;
1319                         $this->message = $message;
1320                 }
1321                 return $this->message;
1322         }
1323
1324         /**
1325          * Formats a message parameter wrapped with 'plaintext'. Ensures that
1326          * the entire string is displayed unchanged when displayed in the output
1327          * format.
1328          *
1329          * @since 1.25
1330          *
1331          * @param string $plaintext String to ensure plaintext output of
1332          * @param string $format One of the FORMAT_* constants.
1333          *
1334          * @return string Input plaintext encoded for output to $format
1335          */
1336         protected function formatPlaintext( $plaintext, $format ) {
1337                 switch ( $format ) {
1338                         case self::FORMAT_TEXT:
1339                         case self::FORMAT_PLAIN:
1340                                 return $plaintext;
1341
1342                         case self::FORMAT_PARSE:
1343                         case self::FORMAT_BLOCK_PARSE:
1344                         case self::FORMAT_ESCAPED:
1345                         default:
1346                                 return htmlspecialchars( $plaintext, ENT_QUOTES );
1347                 }
1348         }
1349
1350         /**
1351          * Formats a list of parameters as a concatenated string.
1352          * @since 1.29
1353          * @param array $params
1354          * @param string $listType
1355          * @param string $format One of the FORMAT_* constants.
1356          * @return array Array with the parameter type (either "before" or "after") and the value.
1357          */
1358         protected function formatListParam( array $params, $listType, $format ) {
1359                 if ( !isset( self::$listTypeMap[$listType] ) ) {
1360                         $warning = 'Invalid list type for message "' . $this->getKey() . '": '
1361                                 . htmlspecialchars( $listType )
1362                                 . ' (params are ' . htmlspecialchars( serialize( $params ) ) . ')';
1363                         trigger_error( $warning, E_USER_WARNING );
1364                         $e = new Exception;
1365                         wfDebugLog( 'Bug58676', $warning . "\n" . $e->getTraceAsString() );
1366                         return [ 'before', '[INVALID]' ];
1367                 }
1368                 $func = self::$listTypeMap[$listType];
1369
1370                 // Handle an empty list sensibly
1371                 if ( !$params ) {
1372                         return [ 'before', $this->getLanguage()->$func( [] ) ];
1373                 }
1374
1375                 // First, determine what kinds of list items we have
1376                 $types = [];
1377                 $vars = [];
1378                 $list = [];
1379                 foreach ( $params as $n => $p ) {
1380                         list( $type, $value ) = $this->extractParam( $p, $format );
1381                         $types[$type] = true;
1382                         $list[] = $value;
1383                         $vars[] = '$' . ( $n + 1 );
1384                 }
1385
1386                 // Easy case: all are 'before' or 'after', so just join the
1387                 // values and use the same type.
1388                 if ( count( $types ) === 1 ) {
1389                         return [ key( $types ), $this->getLanguage()->$func( $list ) ];
1390                 }
1391
1392                 // Hard case: We need to process each value per its type, then
1393                 // return the concatenated values as 'after'. We handle this by turning
1394                 // the list into a RawMessage and processing that as a parameter.
1395                 $vars = $this->getLanguage()->$func( $vars );
1396                 return $this->extractParam( new RawMessage( $vars, $params ), $format );
1397         }
1398 }