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  * @phan-file-suppress PhanCommentParamOnEmptyParamList Cannot make variadic due to HHVM bug,
 162  *   T191668#5263929
 163  */
 164 class Message implements MessageSpecifier, Serializable {
 165         /** Use message text as-is */
 166         const FORMAT_PLAIN = 'plain';
 167         /** Use normal wikitext -> HTML parsing (the result will be wrapped in a block-level HTML tag) */
 168         const FORMAT_BLOCK_PARSE = 'block-parse';
 169         /** Use normal wikitext -> HTML parsing but strip the block-level wrapper */
 170         const FORMAT_PARSE = 'parse';
 171         /** Transform {{..}} constructs but don't transform to HTML */
 172         const FORMAT_TEXT = 'text';
 173         /** Transform {{..}} constructs, HTML-escape the result */
 174         const FORMAT_ESCAPED = 'escaped';
 175
 176         /**
 177          * Mapping from Message::listParam() types to Language methods.
 178          * @var array
 179          */
 180         protected static $listTypeMap = [
 181                 'comma' => 'commaList',
 182                 'semicolon' => 'semicolonList',
 183                 'pipe' => 'pipeList',
 184                 'text' => 'listToText',
 185         ];
 186
 187         /**
 188          * In which language to get this message. True, which is the default,
 189          * means the current user language, false content language.
 190          *
 191          * @var bool
 192          */
 193         protected $interface = true;
 194
 195         /**
 196          * In which language to get this message. Overrides the $interface setting.
 197          *
 198          * @var Language|bool Explicit language object, or false for user language
 199          */
 200         protected $language = false;
 201
 202         /**
 203          * @var string The message key. If $keysToTry has more than one element,
 204          * this may change to one of the keys to try when fetching the message text.
 205          */
 206         protected $key;
 207
 208         /**
 209          * @var string[] List of keys to try when fetching the message.
 210          */
 211         protected $keysToTry;
 212
 213         /**
 214          * @var array List of parameters which will be substituted into the message.
 215          */
 216         protected $parameters = [];
 217
 218         /**
 219          * @var string
 220          * @deprecated
 221          */
 222         protected $format = 'parse';
 223
 224         /**
 225          * @var bool Whether database can be used.
 226          */
 227         protected $useDatabase = true;
 228
 229         /**
 230          * @var Title Title object to use as context.
 231          */
 232         protected $title = null;
 233
 234         /**
 235          * @var Content Content object representing the message.
 236          */
 237         protected $content = null;
 238
 239         /**
 240          * @var string
 241          */
 242         protected $message;
 243
 244         /**
 245          * @since 1.17
 246          * @param string|string[]|MessageSpecifier $key Message key, or array of
 247          * message keys to try and use the first non-empty message for, or a
 248          * MessageSpecifier to copy from.
 249          * @param array $params Message parameters.
 250          * @param Language|null $language [optional] Language to use (defaults to current user language).
 251          * @throws InvalidArgumentException
 252          */
 253         public function __construct( $key, $params = [], Language $language = null ) {
 254                 if ( $key instanceof MessageSpecifier ) {
 255                         if ( $params ) {
 256                                 throw new InvalidArgumentException(
 257                                         '$params must be empty if $key is a MessageSpecifier'
 258                                 );
 259                         }
 260                         $params = $key->getParams();
 261                         $key = $key->getKey();
 262                 }
 263
 264                 if ( !is_string( $key ) && !is_array( $key ) ) {
 265                         throw new InvalidArgumentException( '$key must be a string or an array' );
 266                 }
 267
 268                 $this->keysToTry = (array)$key;
 269
 270                 if ( empty( $this->keysToTry ) ) {
 271                         throw new InvalidArgumentException( '$key must not be an empty list' );
 272                 }
 273
 274                 $this->key = reset( $this->keysToTry );
 275
 276                 $this->parameters = array_values( $params );
 277                 // User language is only resolved in getLanguage(). This helps preserve the
 278                 // semantic intent of "user language" across serialize() and unserialize().
 279                 $this->language = $language ?: false;
 280         }
 281
 282         /**
 283          * @see Serializable::serialize()
 284          * @since 1.26
 285          * @return string
 286          */
 287         public function serialize() {
 288                 return serialize( [
 289                         'interface' => $this->interface,
 290                         'language' => $this->language ? $this->language->getCode() : false,
 291                         'key' => $this->key,
 292                         'keysToTry' => $this->keysToTry,
 293                         'parameters' => $this->parameters,
 294                         'format' => $this->format,
 295                         'useDatabase' => $this->useDatabase,
 296                         'titlestr' => $this->title ? $this->title->getFullText() : null,
 297                 ] );
 298         }
 299
 300         /**
 301          * @see Serializable::unserialize()
 302          * @since 1.26
 303          * @param string $serialized
 304          */
 305         public function unserialize( $serialized ) {
 306                 $data = unserialize( $serialized );
 307                 if ( !is_array( $data ) ) {
 308                         throw new InvalidArgumentException( __METHOD__ . ': Invalid serialized data' );
 309                 }
 310
 311                 $this->interface = $data['interface'];
 312                 $this->key = $data['key'];
 313                 $this->keysToTry = $data['keysToTry'];
 314                 $this->parameters = $data['parameters'];
 315                 $this->format = $data['format'];
 316                 $this->useDatabase = $data['useDatabase'];
 317                 $this->language = $data['language'] ? Language::factory( $data['language'] ) : false;
 318
 319                 if ( isset( $data['titlestr'] ) ) {
 320                         $this->title = Title::newFromText( $data['titlestr'] );
 321                 } elseif ( isset( $data['title'] ) && $data['title'] instanceof Title ) {
 322                         // Old serializations from before December 2018
 323                         $this->title = $data['title'];
 324                 } else {
 325                         $this->title = null; // Explicit for sanity
 326                 }
 327         }
 328
 329         /**
 330          * @since 1.24
 331          *
 332          * @return bool True if this is a multi-key message, that is, if the key provided to the
 333          * constructor was a fallback list of keys to try.
 334          */
 335         public function isMultiKey() {
 336                 return count( $this->keysToTry ) > 1;
 337         }
 338
 339         /**
 340          * @since 1.24
 341          *
 342          * @return string[] The list of keys to try when fetching the message text,
 343          * in order of preference.
 344          */
 345         public function getKeysToTry() {
 346                 return $this->keysToTry;
 347         }
 348
 349         /**
 350          * Returns the message key.
 351          *
 352          * If a list of multiple possible keys was supplied to the constructor, this method may
 353          * return any of these keys. After the message has been fetched, this method will return
 354          * the key that was actually used to fetch the message.
 355          *
 356          * @since 1.21
 357          *
 358          * @return string
 359          */
 360         public function getKey() {
 361                 return $this->key;
 362         }
 363
 364         /**
 365          * Returns the message parameters.
 366          *
 367          * @since 1.21
 368          *
 369          * @return array
 370          */
 371         public function getParams() {
 372                 return $this->parameters;
 373         }
 374
 375         /**
 376          * Returns the message format.
 377          *
 378          * @since 1.21
 379          *
 380          * @return string
 381          * @deprecated since 1.29 formatting is not stateful
 382          */
 383         public function getFormat() {
 384                 wfDeprecated( __METHOD__, '1.29' );
 385                 return $this->format;
 386         }
 387
 388         /**
 389          * Returns the Language of the Message.
 390          *
 391          * @since 1.23
 392          *
 393          * @return Language
 394          */
 395         public function getLanguage() {
 396                 // Defaults to false which means current user language
 397                 return $this->language ?: RequestContext::getMain()->getLanguage();
 398         }
 399
 400         /**
 401          * Factory function that is just wrapper for the real constructor. It is
 402          * intended to be used instead of the real constructor, because it allows
 403          * chaining method calls, while new objects don't.
 404          *
 405          * @since 1.17
 406          *
 407          * @param string|string[]|MessageSpecifier $key
 408          * @param mixed $param,... Parameters as strings.
 409          *
 410          * @return Message
 411          */
 412         public static function newFromKey( $key /*...*/ ) {
 413                 $params = func_get_args();
 414                 array_shift( $params );
 415                 return new self( $key, $params );
 416         }
 417
 418         /**
 419          * Transform a MessageSpecifier or a primitive value used interchangeably with
 420          * specifiers (a message key string, or a key + params array) into a proper Message.
 421          *
 422          * Also accepts a MessageSpecifier inside an array: that's not considered a valid format
 423          * but is an easy error to make due to how StatusValue stores messages internally.
 424          * Further array elements are ignored in that case.
 425          *
 426          * @param string|array|MessageSpecifier $value
 427          * @return Message
 428          * @throws InvalidArgumentException
 429          * @since 1.27
 430          */
 431         public static function newFromSpecifier( $value ) {
 432                 $params = [];
 433                 if ( is_array( $value ) ) {
 434                         $params = $value;
 435                         $value = array_shift( $params );
 436                 }
 437
 438                 if ( $value instanceof Message ) { // Message, RawMessage, ApiMessage, etc
 439                         $message = clone $value;
 440                 } elseif ( $value instanceof MessageSpecifier ) {
 441                         $message = new Message( $value );
 442                 } elseif ( is_string( $value ) ) {
 443                         $message = new Message( $value, $params );
 444                 } else {
 445                         throw new InvalidArgumentException( __METHOD__ . ': invalid argument type '
 446                                 . gettype( $value ) );
 447                 }
 448
 449                 return $message;
 450         }
 451
 452         /**
 453          * Factory function accepting multiple message keys and returning a message instance
 454          * for the first message which is non-empty. If all messages are empty then an
 455          * instance of the first message key is returned.
 456          *
 457          * @since 1.18
 458          *
 459          * @param string|string[] $keys,... Message keys, or first argument as an array of all the
 460          * message keys.
 461          *
 462          * @return Message
 463          */
 464         public static function newFallbackSequence( /*...*/ ) {
 465                 $keys = func_get_args();
 466                 if ( func_num_args() == 1 ) {
 467                         if ( is_array( $keys[0] ) ) {
 468                                 // Allow an array to be passed as the first argument instead
 469                                 $keys = array_values( $keys[0] );
 470                         } else {
 471                                 // Optimize a single string to not need special fallback handling
 472                                 $keys = $keys[0];
 473                         }
 474                 }
 475                 return new self( $keys );
 476         }
 477
 478         /**
 479          * Get a title object for a mediawiki message, where it can be found in the mediawiki namespace.
 480          * The title will be for the current language, if the message key is in
 481          * $wgForceUIMsgAsContentMsg it will be append with the language code (except content
 482          * language), because Message::inContentLanguage will also return in user language.
 483          *
 484          * @see $wgForceUIMsgAsContentMsg
 485          * @return Title
 486          * @since 1.26
 487          */
 488         public function getTitle() {
 489                 global $wgForceUIMsgAsContentMsg;
 490
 491                 $contLang = MediaWikiServices::getInstance()->getContentLanguage();
 492                 $lang = $this->getLanguage();
 493                 $title = $this->key;
 494                 if (
 495                         !$lang->equals( $contLang )
 496                         && in_array( $this->key, (array)$wgForceUIMsgAsContentMsg )
 497                 ) {
 498                         $title .= '/' . $lang->getCode();
 499                 }
 500
 501                 return Title::makeTitle(
 502                         NS_MEDIAWIKI, $contLang->ucfirst( strtr( $title, ' ', '_' ) ) );
 503         }
 504
 505         /**
 506          * Adds parameters to the parameter list of this message.
 507          *
 508          * @since 1.17
 509          *
 510          * @param mixed $args,... Parameters as strings or arrays from
 511          *  Message::numParam() and the like, or a single array of parameters.
 512          *
 513          * @return Message $this
 514          */
 515         public function params( /*...*/ ) {
 516                 $args = func_get_args();
 517
 518                 // If $args has only one entry and it's an array, then it's either a
 519                 // non-varargs call or it happens to be a call with just a single
 520                 // "special" parameter. Since the "special" parameters don't have any
 521                 // numeric keys, we'll test that to differentiate the cases.
 522                 if ( count( $args ) === 1 && isset( $args[0] ) && is_array( $args[0] ) ) {
 523                         if ( $args[0] === [] ) {
 524                                 $args = [];
 525                         } else {
 526                                 foreach ( $args[0] as $key => $value ) {
 527                                         if ( is_int( $key ) ) {
 528                                                 $args = $args[0];
 529                                                 break;
 530                                         }
 531                                 }
 532                         }
 533                 }
 534
 535                 $this->parameters = array_merge( $this->parameters, array_values( $args ) );
 536                 return $this;
 537         }
 538
 539         /**
 540          * Add parameters that are substituted after parsing or escaping.
 541          * In other words the parsing process cannot access the contents
 542          * of this type of parameter, and you need to make sure it is
 543          * sanitized beforehand.  The parser will see "$n", instead.
 544          *
 545          * @since 1.17
 546          *
 547          * @param mixed $params,... Raw parameters as strings, or a single argument that is
 548          * an array of raw parameters.
 549          *
 550          * @return Message $this
 551          */
 552         public function rawParams( /*...*/ ) {
 553                 $params = func_get_args();
 554                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 555                         $params = $params[0];
 556                 }
 557                 foreach ( $params as $param ) {
 558                         $this->parameters[] = self::rawParam( $param );
 559                 }
 560                 return $this;
 561         }
 562
 563         /**
 564          * Add parameters that are numeric and will be passed through
 565          * Language::formatNum before substitution
 566          *
 567          * @since 1.18
 568          *
 569          * @param mixed $param,... Numeric parameters, or a single argument that is
 570          * an array of numeric parameters.
 571          *
 572          * @return Message $this
 573          */
 574         public function numParams( /*...*/ ) {
 575                 $params = func_get_args();
 576                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 577                         $params = $params[0];
 578                 }
 579                 foreach ( $params as $param ) {
 580                         $this->parameters[] = self::numParam( $param );
 581                 }
 582                 return $this;
 583         }
 584
 585         /**
 586          * Add parameters that are durations of time and will be passed through
 587          * Language::formatDuration before substitution
 588          *
 589          * @since 1.22
 590          *
 591          * @param int|int[] $param,... Duration parameters, or a single argument that is
 592          * an array of duration parameters.
 593          *
 594          * @return Message $this
 595          */
 596         public function durationParams( /*...*/ ) {
 597                 $params = func_get_args();
 598                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 599                         $params = $params[0];
 600                 }
 601                 foreach ( $params as $param ) {
 602                         $this->parameters[] = self::durationParam( $param );
 603                 }
 604                 return $this;
 605         }
 606
 607         /**
 608          * Add parameters that are expiration times and will be passed through
 609          * Language::formatExpiry before substitution
 610          *
 611          * @since 1.22
 612          *
 613          * @param string|string[] $param,... Expiry parameters, or a single argument that is
 614          * an array of expiry parameters.
 615          *
 616          * @return Message $this
 617          */
 618         public function expiryParams( /*...*/ ) {
 619                 $params = func_get_args();
 620                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 621                         $params = $params[0];
 622                 }
 623                 foreach ( $params as $param ) {
 624                         $this->parameters[] = self::expiryParam( $param );
 625                 }
 626                 return $this;
 627         }
 628
 629         /**
 630          * Add parameters that are time periods and will be passed through
 631          * Language::formatTimePeriod before substitution
 632          *
 633          * @since 1.22
 634          *
 635          * @param int|int[] $param,... Time period parameters, or a single argument that is
 636          * an array of time period parameters.
 637          *
 638          * @return Message $this
 639          */
 640         public function timeperiodParams( /*...*/ ) {
 641                 $params = func_get_args();
 642                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 643                         $params = $params[0];
 644                 }
 645                 foreach ( $params as $param ) {
 646                         $this->parameters[] = self::timeperiodParam( $param );
 647                 }
 648                 return $this;
 649         }
 650
 651         /**
 652          * Add parameters that are file sizes and will be passed through
 653          * Language::formatSize before substitution
 654          *
 655          * @since 1.22
 656          *
 657          * @param int|int[] $param,... Size parameters, or a single argument that is
 658          * an array of size parameters.
 659          *
 660          * @return Message $this
 661          */
 662         public function sizeParams( /*...*/ ) {
 663                 $params = func_get_args();
 664                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 665                         $params = $params[0];
 666                 }
 667                 foreach ( $params as $param ) {
 668                         $this->parameters[] = self::sizeParam( $param );
 669                 }
 670                 return $this;
 671         }
 672
 673         /**
 674          * Add parameters that are bitrates and will be passed through
 675          * Language::formatBitrate before substitution
 676          *
 677          * @since 1.22
 678          *
 679          * @param int|int[] $param,... Bit rate parameters, or a single argument that is
 680          * an array of bit rate parameters.
 681          *
 682          * @return Message $this
 683          */
 684         public function bitrateParams( /*...*/ ) {
 685                 $params = func_get_args();
 686                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 687                         $params = $params[0];
 688                 }
 689                 foreach ( $params as $param ) {
 690                         $this->parameters[] = self::bitrateParam( $param );
 691                 }
 692                 return $this;
 693         }
 694
 695         /**
 696          * Add parameters that are plaintext and will be passed through without
 697          * the content being evaluated.  Plaintext parameters are not valid as
 698          * arguments to parser functions. This differs from self::rawParams in
 699          * that the Message class handles escaping to match the output format.
 700          *
 701          * @since 1.25
 702          *
 703          * @param string|string[] $param,... plaintext parameters, or a single argument that is
 704          * an array of plaintext parameters.
 705          *
 706          * @return Message $this
 707          */
 708         public function plaintextParams( /*...*/ ) {
 709                 $params = func_get_args();
 710                 if ( isset( $params[0] ) && is_array( $params[0] ) ) {
 711                         $params = $params[0];
 712                 }
 713                 foreach ( $params as $param ) {
 714                         $this->parameters[] = self::plaintextParam( $param );
 715                 }
 716                 return $this;
 717         }
 718
 719         /**
 720          * Set the language and the title from a context object
 721          *
 722          * @since 1.19
 723          *
 724          * @param IContextSource $context
 725          *
 726          * @return Message $this
 727          */
 728         public function setContext( IContextSource $context ) {
 729                 $this->inLanguage( $context->getLanguage() );
 730                 $this->title( $context->getTitle() );
 731                 $this->interface = true;
 732
 733                 return $this;
 734         }
 735
 736         /**
 737          * Request the message in any language that is supported.
 738          *
 739          * As a side effect interface message status is unconditionally
 740          * turned off.
 741          *
 742          * @since 1.17
 743          * @param Language|string $lang Language code or Language object.
 744          * @return Message $this
 745          * @throws MWException
 746          */
 747         public function inLanguage( $lang ) {
 748                 $previousLanguage = $this->language;
 749
 750                 if ( $lang instanceof Language ) {
 751                         $this->language = $lang;
 752                 } elseif ( is_string( $lang ) ) {
 753                         if ( !$this->language instanceof Language || $this->language->getCode() != $lang ) {
 754                                 $this->language = Language::factory( $lang );
 755                         }
 756                 } elseif ( $lang instanceof StubUserLang ) {
 757                         $this->language = false;
 758                 } else {
 759                         $type = gettype( $lang );
 760                         throw new MWException( __METHOD__ . " must be "
 761                                 . "passed a String or Language object; $type given"
 762                         );
 763                 }
 764
 765                 if ( $this->language !== $previousLanguage ) {
 766                         // The language has changed. Clear the message cache.
 767                         $this->message = null;
 768                 }
 769                 $this->interface = false;
 770                 return $this;
 771         }
 772
 773         /**
 774          * Request the message in the wiki's content language,
 775          * unless it is disabled for this message.
 776          *
 777          * @since 1.17
 778          * @see $wgForceUIMsgAsContentMsg
 779          *
 780          * @return Message $this
 781          */
 782         public function inContentLanguage() {
 783                 global $wgForceUIMsgAsContentMsg;
 784                 if ( in_array( $this->key, (array)$wgForceUIMsgAsContentMsg ) ) {
 785                         return $this;
 786                 }
 787
 788                 $this->inLanguage( MediaWikiServices::getInstance()->getContentLanguage() );
 789                 return $this;
 790         }
 791
 792         /**
 793          * Allows manipulating the interface message flag directly.
 794          * Can be used to restore the flag after setting a language.
 795          *
 796          * @since 1.20
 797          *
 798          * @param bool $interface
 799          *
 800          * @return Message $this
 801          */
 802         public function setInterfaceMessageFlag( $interface ) {
 803                 $this->interface = (bool)$interface;
 804                 return $this;
 805         }
 806
 807         /**
 808          * Enable or disable database use.
 809          *
 810          * @since 1.17
 811          *
 812          * @param bool $useDatabase
 813          *
 814          * @return Message $this
 815          */
 816         public function useDatabase( $useDatabase ) {
 817                 $this->useDatabase = (bool)$useDatabase;
 818                 $this->message = null;
 819                 return $this;
 820         }
 821
 822         /**
 823          * Set the Title object to use as context when transforming the message
 824          *
 825          * @since 1.18
 826          *
 827          * @param Title $title
 828          *
 829          * @return Message $this
 830          */
 831         public function title( $title ) {
 832                 $this->title = $title;
 833                 return $this;
 834         }
 835
 836         /**
 837          * Returns the message as a Content object.
 838          *
 839          * @return Content
 840          */
 841         public function content() {
 842                 if ( !$this->content ) {
 843                         $this->content = new MessageContent( $this );
 844                 }
 845
 846                 return $this->content;
 847         }
 848
 849         /**
 850          * Returns the message parsed from wikitext to HTML.
 851          *
 852          * @since 1.17
 853          *
 854          * @param string|null $format One of the FORMAT_* constants. Null means use whatever was used
 855          *   the last time (this is for B/C and should be avoided).
 856          *
 857          * @return string HTML
 858          * @suppress SecurityCheck-DoubleEscaped phan false positive
 859          */
 860         public function toString( $format = null ) {
 861                 if ( $format === null ) {
 862                         $ex = new LogicException( __METHOD__ . ' using implicit format: ' . $this->format );
 863                         LoggerFactory::getInstance( 'message-format' )->warning(
 864                                 $ex->getMessage(), [ 'exception' => $ex, 'format' => $this->format, 'key' => $this->key ] );
 865                         $format = $this->format;
 866                 }
 867                 $string = $this->fetchMessage();
 868
 869                 if ( $string === false ) {
 870                         // Err on the side of safety, ensure that the output
 871                         // is always html safe in the event the message key is
 872                         // missing, since in that case its highly likely the
 873                         // message key is user-controlled.
 874                         // '⧼' is used instead of '<' to side-step any
 875                         // double-escaping issues.
 876                         // (Keep synchronised with mw.Message#toString in JS.)
 877                         return '⧼' . htmlspecialchars( $this->key ) . '⧽';
 878                 }
 879
 880                 # Replace $* with a list of parameters for &uselang=qqx.
 881                 if ( strpos( $string, '$*' ) !== false ) {
 882                         $paramlist = '';
 883                         if ( $this->parameters !== [] ) {
 884                                 $paramlist = ': $' . implode( ', $', range( 1, count( $this->parameters ) ) );
 885                         }
 886                         $string = str_replace( '$*', $paramlist, $string );
 887                 }
 888
 889                 # Replace parameters before text parsing
 890                 $string = $this->replaceParameters( $string, 'before', $format );
 891
 892                 # Maybe transform using the full parser
 893                 if ( $format === self::FORMAT_PARSE ) {
 894                         $string = $this->parseText( $string );
 895                         $string = Parser::stripOuterParagraph( $string );
 896                 } elseif ( $format === self::FORMAT_BLOCK_PARSE ) {
 897                         $string = $this->parseText( $string );
 898                 } elseif ( $format === self::FORMAT_TEXT ) {
 899                         $string = $this->transformText( $string );
 900                 } elseif ( $format === self::FORMAT_ESCAPED ) {
 901                         $string = $this->transformText( $string );
 902                         $string = htmlspecialchars( $string, ENT_QUOTES, 'UTF-8', false );
 903                 }
 904
 905                 # Raw parameter replacement
 906                 $string = $this->replaceParameters( $string, 'after', $format );
 907
 908                 return $string;
 909         }
 910
 911         /**
 912          * Magic method implementation of the above (for PHP >= 5.2.0), so we can do, eg:
 913          *     $foo = new Message( $key );
 914          *     $string = "<abbr>$foo</abbr>";
 915          *
 916          * @since 1.18
 917          *
 918          * @return string
 919          */
 920         public function __toString() {
 921                 // PHP doesn't allow __toString to throw exceptions and will
 922                 // trigger a fatal error if it does. So, catch any exceptions.
 923
 924                 try {
 925                         return $this->toString( self::FORMAT_PARSE );
 926                 } catch ( Exception $ex ) {
 927                         try {
 928                                 trigger_error( "Exception caught in " . __METHOD__ . " (message " . $this->key . "): "
 929                                         . $ex, E_USER_WARNING );
 930                         } catch ( Exception $ex ) {
 931                                 // Doh! Cause a fatal error after all?
 932                         }
 933
 934                         return '⧼' . htmlspecialchars( $this->key ) . '⧽';
 935                 }
 936         }
 937
 938         /**
 939          * Fully parse the text from wikitext to HTML.
 940          *
 941          * @since 1.17
 942          *
 943          * @return string Parsed HTML.
 944          */
 945         public function parse() {
 946                 $this->format = self::FORMAT_PARSE;
 947                 return $this->toString( self::FORMAT_PARSE );
 948         }
 949
 950         /**
 951          * Returns the message text. {{-transformation is done.
 952          *
 953          * @since 1.17
 954          *
 955          * @return string Unescaped message text.
 956          */
 957         public function text() {
 958                 $this->format = self::FORMAT_TEXT;
 959                 return $this->toString( self::FORMAT_TEXT );
 960         }
 961
 962         /**
 963          * Returns the message text as-is, only parameters are substituted.
 964          *
 965          * @since 1.17
 966          *
 967          * @return string Unescaped untransformed message text.
 968          */
 969         public function plain() {
 970                 $this->format = self::FORMAT_PLAIN;
 971                 return $this->toString( self::FORMAT_PLAIN );
 972         }
 973
 974         /**
 975          * Returns the parsed message text which is always surrounded by a block element.
 976          *
 977          * @since 1.17
 978          *
 979          * @return string HTML
 980          */
 981         public function parseAsBlock() {
 982                 $this->format = self::FORMAT_BLOCK_PARSE;
 983                 return $this->toString( self::FORMAT_BLOCK_PARSE );
 984         }
 985
 986         /**
 987          * Returns the message text. {{-transformation is done and the result
 988          * is escaped excluding any raw parameters.
 989          *
 990          * @since 1.17
 991          *
 992          * @return string Escaped message text.
 993          */
 994         public function escaped() {
 995                 $this->format = self::FORMAT_ESCAPED;
 996                 return $this->toString( self::FORMAT_ESCAPED );
 997         }
 998
 999         /**
1000          * Check whether a message key has been defined currently.
1001          *
1002          * @since 1.17
1003          *
1004          * @return bool
1005          */
1006         public function exists() {
1007                 return $this->fetchMessage() !== false;
1008         }
1009
1010         /**
1011          * Check whether a message does not exist, or is an empty string
1012          *
1013          * @since 1.18
1014          * @todo FIXME: Merge with isDisabled()?
1015          *
1016          * @return bool
1017          */
1018         public function isBlank() {
1019                 $message = $this->fetchMessage();
1020                 return $message === false || $message === '';
1021         }
1022
1023         /**
1024          * Check whether a message does not exist, is an empty string, or is "-".
1025          *
1026          * @since 1.18
1027          *
1028          * @return bool
1029          */
1030         public function isDisabled() {
1031                 $message = $this->fetchMessage();
1032                 return $message === false || $message === '' || $message === '-';
1033         }
1034
1035         /**
1036          * @since 1.17
1037          *
1038          * @param mixed $raw
1039          *
1040          * @return array Array with a single "raw" key.
1041          */
1042         public static function rawParam( $raw ) {
1043                 return [ 'raw' => $raw ];
1044         }
1045
1046         /**
1047          * @since 1.18
1048          *
1049          * @param mixed $num
1050          *
1051          * @return array Array with a single "num" key.
1052          */
1053         public static function numParam( $num ) {
1054                 return [ 'num' => $num ];
1055         }
1056
1057         /**
1058          * @since 1.22
1059          *
1060          * @param int $duration
1061          *
1062          * @return int[] Array with a single "duration" key.
1063          */
1064         public static function durationParam( $duration ) {
1065                 return [ 'duration' => $duration ];
1066         }
1067
1068         /**
1069          * @since 1.22
1070          *
1071          * @param string $expiry
1072          *
1073          * @return string[] Array with a single "expiry" key.
1074          */
1075         public static function expiryParam( $expiry ) {
1076                 return [ 'expiry' => $expiry ];
1077         }
1078
1079         /**
1080          * @since 1.22
1081          *
1082          * @param int $period
1083          *
1084          * @return int[] Array with a single "period" key.
1085          */
1086         public static function timeperiodParam( $period ) {
1087                 return [ 'period' => $period ];
1088         }
1089
1090         /**
1091          * @since 1.22
1092          *
1093          * @param int $size
1094          *
1095          * @return int[] Array with a single "size" key.
1096          */
1097         public static function sizeParam( $size ) {
1098                 return [ 'size' => $size ];
1099         }
1100
1101         /**
1102          * @since 1.22
1103          *
1104          * @param int $bitrate
1105          *
1106          * @return int[] Array with a single "bitrate" key.
1107          */
1108         public static function bitrateParam( $bitrate ) {
1109                 return [ 'bitrate' => $bitrate ];
1110         }
1111
1112         /**
1113          * @since 1.25
1114          *
1115          * @param string $plaintext
1116          *
1117          * @return string[] Array with a single "plaintext" key.
1118          */
1119         public static function plaintextParam( $plaintext ) {
1120                 return [ 'plaintext' => $plaintext ];
1121         }
1122
1123         /**
1124          * @since 1.29
1125          *
1126          * @param array $list
1127          * @param string $type 'comma', 'semicolon', 'pipe', 'text'
1128          * @return array Array with "list" and "type" keys.
1129          */
1130         public static function listParam( array $list, $type = 'text' ) {
1131                 if ( !isset( self::$listTypeMap[$type] ) ) {
1132                         throw new InvalidArgumentException(
1133                                 "Invalid type '$type'. Known types are: " . implode( ', ', array_keys( self::$listTypeMap ) )
1134                         );
1135                 }
1136                 return [ 'list' => $list, 'type' => $type ];
1137         }
1138
1139         /**
1140          * Substitutes any parameters into the message text.
1141          *
1142          * @since 1.17
1143          *
1144          * @param string $message The message text.
1145          * @param string $type Either "before" or "after".
1146          * @param string $format One of the FORMAT_* constants.
1147          *
1148          * @return string
1149          */
1150         protected function replaceParameters( $message, $type, $format ) {
1151                 // A temporary marker for $1 parameters that is only valid
1152                 // in non-attribute contexts. However if the entire message is escaped
1153                 // then we don't want to use it because it will be mangled in all contexts
1154                 // and its unnessary as ->escaped() messages aren't html.
1155                 $marker = $format === self::FORMAT_ESCAPED ? '$' : '$\'"';
1156                 $replacementKeys = [];
1157                 foreach ( $this->parameters as $n => $param ) {
1158                         list( $paramType, $value ) = $this->extractParam( $param, $format );
1159                         if ( $type === 'before' ) {
1160                                 if ( $paramType === 'before' ) {
1161                                         $replacementKeys['$' . ( $n + 1 )] = $value;
1162                                 } else /* $paramType === 'after' */ {
1163                                         // To protect against XSS from replacing parameters
1164                                         // inside html attributes, we convert $1 to $'"1.
1165                                         // In the event that one of the parameters ends up
1166                                         // in an attribute, either the ' or the " will be
1167                                         // escaped, breaking the replacement and avoiding XSS.
1168                                         $replacementKeys['$' . ( $n + 1 )] = $marker . ( $n + 1 );
1169                                 }
1170                         } elseif ( $paramType === 'after' ) {
1171                                 $replacementKeys[$marker . ( $n + 1 )] = $value;
1172                         }
1173                 }
1174                 return strtr( $message, $replacementKeys );
1175         }
1176
1177         /**
1178          * Extracts the parameter type and preprocessed the value if needed.
1179          *
1180          * @since 1.18
1181          *
1182          * @param mixed $param Parameter as defined in this class.
1183          * @param string $format One of the FORMAT_* constants.
1184          *
1185          * @return array Array with the parameter type (either "before" or "after") and the value.
1186          */
1187         protected function extractParam( $param, $format ) {
1188                 if ( is_array( $param ) ) {
1189                         if ( isset( $param['raw'] ) ) {
1190                                 return [ 'after', $param['raw'] ];
1191                         } elseif ( isset( $param['num'] ) ) {
1192                                 // Replace number params always in before step for now.
1193                                 // No support for combined raw and num params
1194                                 return [ 'before', $this->getLanguage()->formatNum( $param['num'] ) ];
1195                         } elseif ( isset( $param['duration'] ) ) {
1196                                 return [ 'before', $this->getLanguage()->formatDuration( $param['duration'] ) ];
1197                         } elseif ( isset( $param['expiry'] ) ) {
1198                                 return [ 'before', $this->getLanguage()->formatExpiry( $param['expiry'] ) ];
1199                         } elseif ( isset( $param['period'] ) ) {
1200                                 return [ 'before', $this->getLanguage()->formatTimePeriod( $param['period'] ) ];
1201                         } elseif ( isset( $param['size'] ) ) {
1202                                 return [ 'before', $this->getLanguage()->formatSize( $param['size'] ) ];
1203                         } elseif ( isset( $param['bitrate'] ) ) {
1204                                 return [ 'before', $this->getLanguage()->formatBitrate( $param['bitrate'] ) ];
1205                         } elseif ( isset( $param['plaintext'] ) ) {
1206                                 return [ 'after', $this->formatPlaintext( $param['plaintext'], $format ) ];
1207                         } elseif ( isset( $param['list'] ) ) {
1208                                 return $this->formatListParam( $param['list'], $param['type'], $format );
1209                         } else {
1210                                 if ( !is_scalar( $param ) ) {
1211                                         $param = serialize( $param );
1212                                 }
1213                                 LoggerFactory::getInstance( 'Bug58676' )->warning(
1214                                         'Invalid parameter for message "{msgkey}": {param}',
1215                                         [
1216                                                 'exception' => new Exception,
1217                                                 'msgkey' => $this->getKey(),
1218                                                 'param' => htmlspecialchars( $param ),
1219                                         ]
1220                                 );
1221
1222                                 return [ 'before', '[INVALID]' ];
1223                         }
1224                 } elseif ( $param instanceof Message ) {
1225                         // Match language, flags, etc. to the current message.
1226                         $msg = clone $param;
1227                         if ( $msg->language !== $this->language || $msg->useDatabase !== $this->useDatabase ) {
1228                                 // Cache depends on these parameters
1229                                 $msg->message = null;
1230                         }
1231                         $msg->interface = $this->interface;
1232                         $msg->language = $this->language;
1233                         $msg->useDatabase = $this->useDatabase;
1234                         $msg->title = $this->title;
1235
1236                         // DWIM
1237                         if ( $format === 'block-parse' ) {
1238                                 $format = 'parse';
1239                         }
1240                         $msg->format = $format;
1241
1242                         // Message objects should not be before parameters because
1243                         // then they'll get double escaped. If the message needs to be
1244                         // escaped, it'll happen right here when we call toString().
1245                         return [ 'after', $msg->toString( $format ) ];
1246                 } else {
1247                         return [ 'before', $param ];
1248                 }
1249         }
1250
1251         /**
1252          * Wrapper for what ever method we use to parse wikitext.
1253          *
1254          * @since 1.17
1255          *
1256          * @param string $string Wikitext message contents.
1257          *
1258          * @return string Wikitext parsed into HTML.
1259          */
1260         protected function parseText( $string ) {
1261                 $out = MessageCache::singleton()->parse(
1262                         $string,
1263                         $this->title,
1264                         /*linestart*/true,
1265                         $this->interface,
1266                         $this->getLanguage()
1267                 );
1268
1269                 return $out instanceof ParserOutput
1270                         ? $out->getText( [
1271                                 'enableSectionEditLinks' => false,
1272                                 // Wrapping messages in an extra <div> is probably not expected. If
1273                                 // they're outside the content area they probably shouldn't be
1274                                 // targeted by CSS that's targeting the parser output, and if
1275                                 // they're inside they already are from the outer div.
1276                                 'unwrap' => true,
1277                         ] )
1278                         : $out;
1279         }
1280
1281         /**
1282          * Wrapper for what ever method we use to {{-transform wikitext.
1283          *
1284          * @since 1.17
1285          *
1286          * @param string $string Wikitext message contents.
1287          *
1288          * @return string Wikitext with {{-constructs replaced with their values.
1289          */
1290         protected function transformText( $string ) {
1291                 return MessageCache::singleton()->transform(
1292                         $string,
1293                         $this->interface,
1294                         $this->getLanguage(),
1295                         $this->title
1296                 );
1297         }
1298
1299         /**
1300          * Wrapper for what ever method we use to get message contents.
1301          *
1302          * @since 1.17
1303          *
1304          * @return string
1305          * @throws MWException If message key array is empty.
1306          */
1307         protected function fetchMessage() {
1308                 if ( $this->message === null ) {
1309                         $cache = MessageCache::singleton();
1310
1311                         foreach ( $this->keysToTry as $key ) {
1312                                 $message = $cache->get( $key, $this->useDatabase, $this->getLanguage() );
1313                                 if ( $message !== false && $message !== '' ) {
1314                                         break;
1315                                 }
1316                         }
1317
1318                         // NOTE: The constructor makes sure keysToTry isn't empty,
1319                         //       so we know that $key and $message are initialized.
1320                         $this->key = $key;
1321                         $this->message = $message;
1322                 }
1323                 return $this->message;
1324         }
1325
1326         /**
1327          * Formats a message parameter wrapped with 'plaintext'. Ensures that
1328          * the entire string is displayed unchanged when displayed in the output
1329          * format.
1330          *
1331          * @since 1.25
1332          *
1333          * @param string $plaintext String to ensure plaintext output of
1334          * @param string $format One of the FORMAT_* constants.
1335          *
1336          * @return string Input plaintext encoded for output to $format
1337          */
1338         protected function formatPlaintext( $plaintext, $format ) {
1339                 switch ( $format ) {
1340                         case self::FORMAT_TEXT:
1341                         case self::FORMAT_PLAIN:
1342                                 return $plaintext;
1343
1344                         case self::FORMAT_PARSE:
1345                         case self::FORMAT_BLOCK_PARSE:
1346                         case self::FORMAT_ESCAPED:
1347                         default:
1348                                 return htmlspecialchars( $plaintext, ENT_QUOTES );
1349                 }
1350         }
1351
1352         /**
1353          * Formats a list of parameters as a concatenated string.
1354          * @since 1.29
1355          * @param array $params
1356          * @param string $listType
1357          * @param string $format One of the FORMAT_* constants.
1358          * @return array Array with the parameter type (either "before" or "after") and the value.
1359          */
1360         protected function formatListParam( array $params, $listType, $format ) {
1361                 if ( !isset( self::$listTypeMap[$listType] ) ) {
1362                         $warning = 'Invalid list type for message "' . $this->getKey() . '": '
1363                                 . htmlspecialchars( $listType )
1364                                 . ' (params are ' . htmlspecialchars( serialize( $params ) ) . ')';
1365                         trigger_error( $warning, E_USER_WARNING );
1366                         $e = new Exception;
1367                         wfDebugLog( 'Bug58676', $warning . "\n" . $e->getTraceAsString() );
1368                         return [ 'before', '[INVALID]' ];
1369                 }
1370                 $func = self::$listTypeMap[$listType];
1371
1372                 // Handle an empty list sensibly
1373                 if ( !$params ) {
1374                         return [ 'before', $this->getLanguage()->$func( [] ) ];
1375                 }
1376
1377                 // First, determine what kinds of list items we have
1378                 $types = [];
1379                 $vars = [];
1380                 $list = [];
1381                 foreach ( $params as $n => $p ) {
1382                         list( $type, $value ) = $this->extractParam( $p, $format );
1383                         $types[$type] = true;
1384                         $list[] = $value;
1385                         $vars[] = '$' . ( $n + 1 );
1386                 }
1387
1388                 // Easy case: all are 'before' or 'after', so just join the
1389                 // values and use the same type.
1390                 if ( count( $types ) === 1 ) {
1391                         return [ key( $types ), $this->getLanguage()->$func( $list ) ];
1392                 }
1393
1394                 // Hard case: We need to process each value per its type, then
1395                 // return the concatenated values as 'after'. We handle this by turning
1396                 // the list into a RawMessage and processing that as a parameter.
1397                 $vars = $this->getLanguage()->$func( $vars );
1398                 return $this->extractParam( new RawMessage( $vars, $params ), $format );
1399         }
1400 }