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