includes/logging/LogFormatter.php

   1 <?php
   2 /**
   3  * Contains classes for formatting log entries
   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  * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License 2.0 or later
  23  * @since 1.19
  24  */
  25
  26 /**
  27  * Implements the default log formatting.
  28  * Can be overridden by subclassing and setting
  29  * $wgLogActionsHandlers['type/subtype'] = 'class'; or
  30  * $wgLogActionsHandlers['type/*'] = 'class';
  31  * @since 1.19
  32  */
  33 class LogFormatter {
  34         // Audience options for viewing usernames, comments, and actions
  35         const FOR_PUBLIC = 1;
  36         const FOR_THIS_USER = 2;
  37
  38         // Static->
  39
  40         /**
  41          * Constructs a new formatter suitable for given entry.
  42          * @param LogEntry $entry
  43          * @return LogFormatter
  44          */
  45         public static function newFromEntry( LogEntry $entry ) {
  46                 global $wgLogActionsHandlers;
  47                 $fulltype = $entry->getFullType();
  48                 $wildcard = $entry->getType() . '/*';
  49                 $handler = '';
  50
  51                 if ( isset( $wgLogActionsHandlers[$fulltype] ) ) {
  52                         $handler = $wgLogActionsHandlers[$fulltype];
  53                 } elseif ( isset( $wgLogActionsHandlers[$wildcard] ) ) {
  54                         $handler = $wgLogActionsHandlers[$wildcard];
  55                 }
  56
  57                 if ( $handler !== '' && is_string( $handler ) && class_exists( $handler ) ) {
  58                         return new $handler( $entry );
  59                 }
  60
  61                 return new LegacyLogFormatter( $entry );
  62         }
  63
  64         /**
  65          * Handy shortcut for constructing a formatter directly from
  66          * database row.
  67          * @param $row
  68          * @see DatabaseLogEntry::getSelectQueryData
  69          * @return LogFormatter
  70          */
  71         public static function newFromRow( $row ) {
  72                 return self::newFromEntry( DatabaseLogEntry::newFromRow( $row ) );
  73         }
  74
  75         // Nonstatic->
  76
  77         /** @var LogEntryBase */
  78         protected $entry;
  79
  80         /// Integer constant for handling log_deleted
  81         protected $audience = self::FOR_PUBLIC;
  82
  83         /// Whether to output user tool links
  84         protected $linkFlood = false;
  85
  86         /**
  87          * Set to true if we are constructing a message text that is going to
  88          * be included in page history or send to IRC feed. Links are replaced
  89          * with plaintext or with [[pagename]] kind of syntax, that is parsed
  90          * by page histories and IRC feeds.
  91          * @var string
  92          */
  93         protected $plaintext = false;
  94
  95         /** @var string */
  96         protected $irctext = false;
  97
  98         protected function __construct( LogEntry $entry ) {
  99                 $this->entry = $entry;
 100                 $this->context = RequestContext::getMain();
 101         }
 102
 103         /**
 104          * Replace the default context
 105          * @param IContextSource $context
 106          */
 107         public function setContext( IContextSource $context ) {
 108                 $this->context = $context;
 109         }
 110
 111         /**
 112          * Set the visibility restrictions for displaying content.
 113          * If set to public, and an item is deleted, then it will be replaced
 114          * with a placeholder even if the context user is allowed to view it.
 115          * @param int $audience self::FOR_THIS_USER or self::FOR_PUBLIC
 116          */
 117         public function setAudience( $audience ) {
 118                 $this->audience = ( $audience == self::FOR_THIS_USER )
 119                         ? self::FOR_THIS_USER
 120                         : self::FOR_PUBLIC;
 121         }
 122
 123         /**
 124          * Check if a log item can be displayed
 125          * @param int $field LogPage::DELETED_* constant
 126          * @return bool
 127          */
 128         protected function canView( $field ) {
 129                 if ( $this->audience == self::FOR_THIS_USER ) {
 130                         return LogEventsList::userCanBitfield(
 131                                 $this->entry->getDeleted(), $field, $this->context->getUser() );
 132                 } else {
 133                         return !$this->entry->isDeleted( $field );
 134                 }
 135         }
 136
 137         /**
 138          * If set to true, will produce user tool links after
 139          * the user name. This should be replaced with generic
 140          * CSS/JS solution.
 141          * @param bool $value
 142          */
 143         public function setShowUserToolLinks( $value ) {
 144                 $this->linkFlood = $value;
 145         }
 146
 147         /**
 148          * Ugly hack to produce plaintext version of the message.
 149          * Usually you also want to set extraneous request context
 150          * to avoid formatting for any particular user.
 151          * @see getActionText()
 152          * @return string Plain text
 153          */
 154         public function getPlainActionText() {
 155                 $this->plaintext = true;
 156                 $text = $this->getActionText();
 157                 $this->plaintext = false;
 158
 159                 return $text;
 160         }
 161
 162         /**
 163          * Even uglier hack to maintain backwards compatibilty with IRC bots
 164          * (bug 34508).
 165          * @see getActionText()
 166          * @return string text
 167          */
 168         public function getIRCActionComment() {
 169                 $actionComment = $this->getIRCActionText();
 170                 $comment = $this->entry->getComment();
 171
 172                 if ( $comment != '' ) {
 173                         if ( $actionComment == '' ) {
 174                                 $actionComment = $comment;
 175                         } else {
 176                                 $actionComment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $comment;
 177                         }
 178                 }
 179
 180                 return $actionComment;
 181         }
 182
 183         /**
 184          * Even uglier hack to maintain backwards compatibilty with IRC bots
 185          * (bug 34508).
 186          * @see getActionText()
 187          * @return string text
 188          */
 189         public function getIRCActionText() {
 190                 $this->plaintext = true;
 191                 $this->irctext = true;
 192
 193                 $entry = $this->entry;
 194                 $parameters = $entry->getParameters();
 195                 // @see LogPage::actionText()
 196                 // Text of title the action is aimed at.
 197                 $target = $entry->getTarget()->getPrefixedText();
 198                 $text = null;
 199                 switch ( $entry->getType() ) {
 200                         case 'move':
 201                                 switch ( $entry->getSubtype() ) {
 202                                         case 'move':
 203                                                 $movesource = $parameters['4::target'];
 204                                                 $text = wfMessage( '1movedto2' )
 205                                                         ->rawParams( $target, $movesource )->inContentLanguage()->escaped();
 206                                                 break;
 207                                         case 'move_redir':
 208                                                 $movesource = $parameters['4::target'];
 209                                                 $text = wfMessage( '1movedto2_redir' )
 210                                                         ->rawParams( $target, $movesource )->inContentLanguage()->escaped();
 211                                                 break;
 212                                         case 'move-noredirect':
 213                                                 break;
 214                                         case 'move_redir-noredirect':
 215                                                 break;
 216                                 }
 217                                 break;
 218
 219                         case 'delete':
 220                                 switch ( $entry->getSubtype() ) {
 221                                         case 'delete':
 222                                                 $text = wfMessage( 'deletedarticle' )
 223                                                         ->rawParams( $target )->inContentLanguage()->escaped();
 224                                                 break;
 225                                         case 'restore':
 226                                                 $text = wfMessage( 'undeletedarticle' )
 227                                                         ->rawParams( $target )->inContentLanguage()->escaped();
 228                                                 break;
 229                                         // @codingStandardsIgnoreStart Long line
 230                                         //case 'revision': // Revision deletion
 231                                         //case 'event': // Log deletion
 232                                         // see https://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/includes/LogPage.php?&pathrev=97044&r1=97043&r2=97044
 233                                         //default:
 234                                         // @codingStandardsIgnoreEnd
 235                                 }
 236                                 break;
 237
 238                         case 'patrol':
 239                                 // @codingStandardsIgnoreStart Long line
 240                                 // https://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/includes/PatrolLog.php?&pathrev=97495&r1=97494&r2=97495
 241                                 // @codingStandardsIgnoreEnd
 242                                 // Create a diff link to the patrolled revision
 243                                 if ( $entry->getSubtype() === 'patrol' ) {
 244                                         $diffLink = htmlspecialchars(
 245                                                 wfMessage( 'patrol-log-diff', $parameters['4::curid'] )
 246                                                         ->inContentLanguage()->text() );
 247                                         $text = wfMessage( 'patrol-log-line', $diffLink, "[[$target]]", "" )
 248                                                 ->inContentLanguage()->text();
 249                                 } else {
 250                                         // broken??
 251                                 }
 252                                 break;
 253
 254                         case 'protect':
 255                                 switch ( $entry->getSubtype() ) {
 256                                         case 'protect':
 257                                                 $text = wfMessage( 'protectedarticle' )
 258                                                         ->rawParams( $target . ' ' . $parameters[0] )->inContentLanguage()->escaped();
 259                                                 break;
 260                                         case 'unprotect':
 261                                                 $text = wfMessage( 'unprotectedarticle' )
 262                                                         ->rawParams( $target )->inContentLanguage()->escaped();
 263                                                 break;
 264                                         case 'modify':
 265                                                 $text = wfMessage( 'modifiedarticleprotection' )
 266                                                         ->rawParams( $target . ' ' . $parameters[0] )->inContentLanguage()->escaped();
 267                                                 break;
 268                                 }
 269                                 break;
 270
 271                         case 'newusers':
 272                                 switch ( $entry->getSubtype() ) {
 273                                         case 'newusers':
 274                                         case 'create':
 275                                                 $text = wfMessage( 'newuserlog-create-entry' )
 276                                                         ->inContentLanguage()->escaped();
 277                                                 break;
 278                                         case 'create2':
 279                                         case 'byemail':
 280                                                 $text = wfMessage( 'newuserlog-create2-entry' )
 281                                                         ->rawParams( $target )->inContentLanguage()->escaped();
 282                                                 break;
 283                                         case 'autocreate':
 284                                                 $text = wfMessage( 'newuserlog-autocreate-entry' )
 285                                                         ->inContentLanguage()->escaped();
 286                                                 break;
 287                                 }
 288                                 break;
 289
 290                         case 'upload':
 291                                 switch ( $entry->getSubtype() ) {
 292                                         case 'upload':
 293                                                 $text = wfMessage( 'uploadedimage' )
 294                                                         ->rawParams( $target )->inContentLanguage()->escaped();
 295                                                 break;
 296                                         case 'overwrite':
 297                                                 $text = wfMessage( 'overwroteimage' )
 298                                                         ->rawParams( $target )->inContentLanguage()->escaped();
 299                                                 break;
 300                                 }
 301                                 break;
 302
 303                         case 'rights':
 304                                 if ( count( $parameters['4::oldgroups'] ) ) {
 305                                         $oldgroups = implode( ', ', $parameters['4::oldgroups'] );
 306                                 } else {
 307                                         $oldgroups = wfMessage( 'rightsnone' )->inContentLanguage()->escaped();
 308                                 }
 309                                 if ( count( $parameters['5::newgroups'] ) ) {
 310                                         $newgroups = implode( ', ', $parameters['5::newgroups'] );
 311                                 } else {
 312                                         $newgroups = wfMessage( 'rightsnone' )->inContentLanguage()->escaped();
 313                                 }
 314                                 switch ( $entry->getSubtype() ) {
 315                                         case 'rights':
 316                                                 $text = wfMessage( 'rightslogentry' )
 317                                                         ->rawParams( $target, $oldgroups, $newgroups )->inContentLanguage()->escaped();
 318                                                 break;
 319                                         case 'autopromote':
 320                                                 $text = wfMessage( 'rightslogentry-autopromote' )
 321                                                         ->rawParams( $target, $oldgroups, $newgroups )->inContentLanguage()->escaped();
 322                                                 break;
 323                                 }
 324                                 break;
 325                         // case 'suppress' --private log -- aaron  (so we know who to blame in a few years :-D)
 326                         // default:
 327                 }
 328                 if ( is_null( $text ) ) {
 329                         $text = $this->getPlainActionText();
 330                 }
 331
 332                 $this->plaintext = false;
 333                 $this->irctext = false;
 334
 335                 return $text;
 336         }
 337
 338         /**
 339          * Gets the log action, including username.
 340          * @return string HTML
 341          */
 342         public function getActionText() {
 343                 if ( $this->canView( LogPage::DELETED_ACTION ) ) {
 344                         $element = $this->getActionMessage();
 345                         if ( $element instanceof Message ) {
 346                                 $element = $this->plaintext ? $element->text() : $element->escaped();
 347                         }
 348                         if ( $this->entry->isDeleted( LogPage::DELETED_ACTION ) ) {
 349                                 $element = $this->styleRestricedElement( $element );
 350                         }
 351                 } else {
 352                         $performer = $this->getPerformerElement() . $this->msg( 'word-separator' )->text();
 353                         $element = $performer . $this->getRestrictedElement( 'rev-deleted-event' );
 354                 }
 355
 356                 return $element;
 357         }
 358
 359         /**
 360          * Returns a sentence describing the log action. Usually
 361          * a Message object is returned, but old style log types
 362          * and entries might return pre-escaped HTML string.
 363          * @return Message|string Pre-escaped HTML
 364          */
 365         protected function getActionMessage() {
 366                 $message = $this->msg( $this->getMessageKey() );
 367                 $message->params( $this->getMessageParameters() );
 368
 369                 return $message;
 370         }
 371
 372         /**
 373          * Returns a key to be used for formatting the action sentence.
 374          * Default is logentry-TYPE-SUBTYPE for modern logs. Legacy log
 375          * types will use custom keys, and subclasses can also alter the
 376          * key depending on the entry itself.
 377          * @return string Message key
 378          */
 379         protected function getMessageKey() {
 380                 $type = $this->entry->getType();
 381                 $subtype = $this->entry->getSubtype();
 382
 383                 return "logentry-$type-$subtype";
 384         }
 385
 386         /**
 387          * Returns extra links that comes after the action text, like "revert", etc.
 388          *
 389          * @return string
 390          */
 391         public function getActionLinks() {
 392                 return '';
 393         }
 394
 395         /**
 396          * Extracts the optional extra parameters for use in action messages.
 397          * The array indexes start from number 3.
 398          * @return array
 399          */
 400         protected function extractParameters() {
 401                 $entry = $this->entry;
 402                 $params = array();
 403
 404                 if ( $entry->isLegacy() ) {
 405                         foreach ( $entry->getParameters() as $index => $value ) {
 406                                 $params[$index + 3] = $value;
 407                         }
 408                 }
 409
 410                 // Filter out parameters which are not in format #:foo
 411                 foreach ( $entry->getParameters() as $key => $value ) {
 412                         if ( strpos( $key, ':' ) === false ) {
 413                                 continue;
 414                         }
 415                         list( $index, $type, ) = explode( ':', $key, 3 );
 416                         $params[$index - 1] = $this->formatParameterValue( $type, $value );
 417                 }
 418
 419                 /* Message class doesn't like non consecutive numbering.
 420                  * Fill in missing indexes with empty strings to avoid
 421                  * incorrect renumbering.
 422                  */
 423                 if ( count( $params ) ) {
 424                         $max = max( array_keys( $params ) );
 425                         for ( $i = 4; $i < $max; $i++ ) {
 426                                 if ( !isset( $params[$i] ) ) {
 427                                         $params[$i] = '';
 428                                 }
 429                         }
 430                 }
 431
 432                 return $params;
 433         }
 434
 435         /**
 436          * Formats parameters intented for action message from
 437          * array of all parameters. There are three hardcoded
 438          * parameters (array is zero-indexed, this list not):
 439          *  - 1: user name with premade link
 440          *  - 2: usable for gender magic function
 441          *  - 3: target page with premade link
 442          * @return array
 443          */
 444         protected function getMessageParameters() {
 445                 if ( isset( $this->parsedParameters ) ) {
 446                         return $this->parsedParameters;
 447                 }
 448
 449                 $entry = $this->entry;
 450                 $params = $this->extractParameters();
 451                 $params[0] = Message::rawParam( $this->getPerformerElement() );
 452                 $params[1] = $this->canView( LogPage::DELETED_USER ) ? $entry->getPerformer()->getName() : '';
 453                 $params[2] = Message::rawParam( $this->makePageLink( $entry->getTarget() ) );
 454
 455                 // Bad things happens if the numbers are not in correct order
 456                 ksort( $params );
 457
 458                 $this->parsedParameters = $params;
 459                 return $this->parsedParameters;
 460         }
 461
 462         /**
 463          * Formats parameters values dependent to their type
 464          * @param string $type The type of the value.
 465          *   Valid are currently:
 466          *     * - (empty) or plain: The value is returned as-is
 467          *     * raw: The value will be added to the log message
 468          *            as raw parameter (e.g. no escaping)
 469          *            Use this only if there is no other working
 470          *            type like user-link or title-link
 471          *     * msg: The value is a message-key, the output is
 472          *            the message in user language
 473          *     * msg-content: The value is a message-key, the output
 474          *                    is the message in content language
 475          *     * user: The value is a user name, e.g. for GENDER
 476          *     * user-link: The value is a user name, returns a
 477          *                  link for the user
 478          *     * title: The value is a page title,
 479          *              returns name of page
 480          *     * title-link: The value is a page title,
 481          *                   returns link to this page
 482          *     * number: Format value as number
 483          * @param string $value The parameter value that should
 484          *                      be formated
 485          * @return string|Message::numParam|Message::rawParam
 486          *         Formated value
 487          * @since 1.21
 488          */
 489         protected function formatParameterValue( $type, $value ) {
 490                 $saveLinkFlood = $this->linkFlood;
 491
 492                 switch ( strtolower( trim( $type ) ) ) {
 493                         case 'raw':
 494                                 $value = Message::rawParam( $value );
 495                                 break;
 496                         case 'msg':
 497                                 $value = $this->msg( $value )->text();
 498                                 break;
 499                         case 'msg-content':
 500                                 $value = $this->msg( $value )->inContentLanguage()->text();
 501                                 break;
 502                         case 'number':
 503                                 $value = Message::numParam( $value );
 504                                 break;
 505                         case 'user':
 506                                 $user = User::newFromName( $value );
 507                                 $value = $user->getName();
 508                                 break;
 509                         case 'user-link':
 510                                 $this->setShowUserToolLinks( false );
 511
 512                                 $user = User::newFromName( $value );
 513                                 $value = Message::rawParam( $this->makeUserLink( $user ) );
 514
 515                                 $this->setShowUserToolLinks( $saveLinkFlood );
 516                                 break;
 517                         case 'title':
 518                                 $title = Title::newFromText( $value );
 519                                 $value = $title->getPrefixedText();
 520                                 break;
 521                         case 'title-link':
 522                                 $title = Title::newFromText( $value );
 523                                 $value = Message::rawParam( $this->makePageLink( $title ) );
 524                                 break;
 525                         case 'plain':
 526                                 // Plain text, nothing to do
 527                         default:
 528                                 // Catch other types and use the old behavior (return as-is)
 529                 }
 530
 531                 return $value;
 532         }
 533
 534         /**
 535          * Helper to make a link to the page, taking the plaintext
 536          * value in consideration.
 537          * @param Title $title The page
 538          * @param array $parameters Query parameters
 539          * @throws MWException
 540          * @return string
 541          */
 542         protected function makePageLink( Title $title = null, $parameters = array() ) {
 543                 if ( !$this->plaintext ) {
 544                         $link = Linker::link( $title, null, array(), $parameters );
 545                 } else {
 546                         if ( !$title instanceof Title ) {
 547                                 throw new MWException( "Expected title, got null" );
 548                         }
 549                         $link = '[[' . $title->getPrefixedText() . ']]';
 550                 }
 551
 552                 return $link;
 553         }
 554
 555         /**
 556          * Provides the name of the user who performed the log action.
 557          * Used as part of log action message or standalone, depending
 558          * which parts of the log entry has been hidden.
 559          * @return string
 560          */
 561         public function getPerformerElement() {
 562                 if ( $this->canView( LogPage::DELETED_USER ) ) {
 563                         $performer = $this->entry->getPerformer();
 564                         $element = $this->makeUserLink( $performer );
 565                         if ( $this->entry->isDeleted( LogPage::DELETED_USER ) ) {
 566                                 $element = $this->styleRestricedElement( $element );
 567                         }
 568                 } else {
 569                         $element = $this->getRestrictedElement( 'rev-deleted-user' );
 570                 }
 571
 572                 return $element;
 573         }
 574
 575         /**
 576          * Gets the user provided comment
 577          * @return string HTML
 578          */
 579         public function getComment() {
 580                 if ( $this->canView( LogPage::DELETED_COMMENT ) ) {
 581                         $comment = Linker::commentBlock( $this->entry->getComment() );
 582                         // No hard coded spaces thanx
 583                         $element = ltrim( $comment );
 584                         if ( $this->entry->isDeleted( LogPage::DELETED_COMMENT ) ) {
 585                                 $element = $this->styleRestricedElement( $element );
 586                         }
 587                 } else {
 588                         $element = $this->getRestrictedElement( 'rev-deleted-comment' );
 589                 }
 590
 591                 return $element;
 592         }
 593
 594         /**
 595          * Helper method for displaying restricted element.
 596          * @param string $message
 597          * @return string HTML or wiki text
 598          */
 599         protected function getRestrictedElement( $message ) {
 600                 if ( $this->plaintext ) {
 601                         return $this->msg( $message )->text();
 602                 }
 603
 604                 $content = $this->msg( $message )->escaped();
 605                 $attribs = array( 'class' => 'history-deleted' );
 606
 607                 return Html::rawElement( 'span', $attribs, $content );
 608         }
 609
 610         /**
 611          * Helper method for styling restricted element.
 612          * @param string $content
 613          * @return string HTML or wiki text
 614          */
 615         protected function styleRestricedElement( $content ) {
 616                 if ( $this->plaintext ) {
 617                         return $content;
 618                 }
 619                 $attribs = array( 'class' => 'history-deleted' );
 620
 621                 return Html::rawElement( 'span', $attribs, $content );
 622         }
 623
 624         /**
 625          * Shortcut for wfMessage which honors local context.
 626          * @param string $key
 627          * @return Message
 628          */
 629         protected function msg( $key ) {
 630                 return $this->context->msg( $key );
 631         }
 632
 633         protected function makeUserLink( User $user ) {
 634                 if ( $this->plaintext ) {
 635                         $element = $user->getName();
 636                 } else {
 637                         $element = Linker::userLink(
 638                                 $user->getId(),
 639                                 $user->getName()
 640                         );
 641
 642                         if ( $this->linkFlood ) {
 643                                 $element .= Linker::userToolLinksRedContribs(
 644                                         $user->getId(),
 645                                         $user->getName(),
 646                                         $user->getEditCount()
 647                                 );
 648                         }
 649                 }
 650
 651                 return $element;
 652         }
 653
 654         /**
 655          * @return array of titles that should be preloaded with LinkBatch.
 656          */
 657         public function getPreloadTitles() {
 658                 return array();
 659         }
 660
 661         /**
 662          * @return array Output of getMessageParameters() for testing
 663          */
 664         public function getMessageParametersForTesting() {
 665                 // This function was added because getMessageParameters() is
 666                 // protected and a change from protected to public caused
 667                 // problems with extensions
 668                 return $this->getMessageParameters();
 669         }
 670 }
 671
 672 /**
 673  * This class formats all log entries for log types
 674  * which have not been converted to the new system.
 675  * This is not about old log entries which store
 676  * parameters in a different format - the new
 677  * LogFormatter classes have code to support formatting
 678  * those too.
 679  * @since 1.19
 680  */
 681 class LegacyLogFormatter extends LogFormatter {
 682         /**
 683          * Backward compatibility for extension changing the comment from
 684          * the LogLine hook. This will be set by the first call on getComment(),
 685          * then it might be modified by the hook when calling getActionLinks(),
 686          * so that the modified value will be returned when calling getComment()
 687          * a second time.
 688          *
 689          * @var string|null
 690          */
 691         private $comment = null;
 692
 693         /**
 694          * Cache for the result of getActionLinks() so that it does not need to
 695          * run multiple times depending on the order that getComment() and
 696          * getActionLinks() are called.
 697          *
 698          * @var string|null
 699          */
 700         private $revert = null;
 701
 702         public function getComment() {
 703                 if ( $this->comment === null ) {
 704                         $this->comment = parent::getComment();
 705                 }
 706
 707                 // Make sure we execute the LogLine hook so that we immediately return
 708                 // the correct value.
 709                 if ( $this->revert === null ) {
 710                         $this->getActionLinks();
 711                 }
 712
 713                 return $this->comment;
 714         }
 715
 716         protected function getActionMessage() {
 717                 $entry = $this->entry;
 718                 $action = LogPage::actionText(
 719                         $entry->getType(),
 720                         $entry->getSubtype(),
 721                         $entry->getTarget(),
 722                         $this->plaintext ? null : $this->context->getSkin(),
 723                         (array)$entry->getParameters(),
 724                         !$this->plaintext // whether to filter [[]] links
 725                 );
 726
 727                 $performer = $this->getPerformerElement();
 728                 if ( !$this->irctext ) {
 729                         $action = $performer . $this->msg( 'word-separator' )->text() . $action;
 730                 }
 731
 732                 return $action;
 733         }
 734
 735         public function getActionLinks() {
 736                 if ( $this->revert !== null ) {
 737                         return $this->revert;
 738                 }
 739
 740                 if ( $this->entry->isDeleted( LogPage::DELETED_ACTION ) ) {
 741                         $this->revert = '';
 742                         return $this->revert;
 743                 }
 744
 745                 $title = $this->entry->getTarget();
 746                 $type = $this->entry->getType();
 747                 $subtype = $this->entry->getSubtype();
 748
 749                 // Show unblock/change block link
 750                 if ( ( $type == 'block' || $type == 'suppress' )
 751                         && ( $subtype == 'block' || $subtype == 'reblock' )
 752                 ) {
 753                         if ( !$this->context->getUser()->isAllowed( 'block' ) ) {
 754                                 return '';
 755                         }
 756
 757                         $links = array(
 758                                 Linker::linkKnown(
 759                                         SpecialPage::getTitleFor( 'Unblock', $title->getDBkey() ),
 760                                         $this->msg( 'unblocklink' )->escaped()
 761                                 ),
 762                                 Linker::linkKnown(
 763                                         SpecialPage::getTitleFor( 'Block', $title->getDBkey() ),
 764                                         $this->msg( 'change-blocklink' )->escaped()
 765                                 )
 766                         );
 767
 768                         return $this->msg( 'parentheses' )->rawParams(
 769                                 $this->context->getLanguage()->pipeList( $links ) )->escaped();
 770                 // Show change protection link
 771                 } elseif ( $type == 'protect'
 772                         && ( $subtype == 'protect' || $subtype == 'modify' || $subtype == 'unprotect' )
 773                 ) {
 774                         $links = array(
 775                                 Linker::link( $title,
 776                                         $this->msg( 'hist' )->escaped(),
 777                                         array(),
 778                                         array(
 779                                                 'action' => 'history',
 780                                                 'offset' => $this->entry->getTimestamp()
 781                                         )
 782                                 )
 783                         );
 784                         if ( $this->context->getUser()->isAllowed( 'protect' ) ) {
 785                                 $links[] = Linker::linkKnown(
 786                                         $title,
 787                                         $this->msg( 'protect_change' )->escaped(),
 788                                         array(),
 789                                         array( 'action' => 'protect' )
 790                                 );
 791                         }
 792
 793                         return $this->msg( 'parentheses' )->rawParams(
 794                                 $this->context->getLanguage()->pipeList( $links ) )->escaped();
 795                 // Show unmerge link
 796                 } elseif ( $type == 'merge' && $subtype == 'merge' ) {
 797                         if ( !$this->context->getUser()->isAllowed( 'mergehistory' ) ) {
 798                                 return '';
 799                         }
 800
 801                         $params = $this->extractParameters();
 802                         $revert = Linker::linkKnown(
 803                                 SpecialPage::getTitleFor( 'MergeHistory' ),
 804                                 $this->msg( 'revertmerge' )->escaped(),
 805                                 array(),
 806                                 array(
 807                                         'target' => $params[3],
 808                                         'dest' => $title->getPrefixedDBkey(),
 809                                         'mergepoint' => $params[4]
 810                                 )
 811                         );
 812
 813                         return $this->msg( 'parentheses' )->rawParams( $revert )->escaped();
 814                 }
 815
 816                 // Do nothing. The implementation is handled by the hook modifiying the
 817                 // passed-by-ref parameters. This also changes the default value so that
 818                 // getComment() and getActionLinks() do not call them indefinitely.
 819                 $this->revert = '';
 820
 821                 // This is to populate the $comment member of this instance so that it
 822                 // can be modified when calling the hook just below.
 823                 if ( $this->comment === null ) {
 824                         $this->getComment();
 825                 }
 826
 827                 $params = $this->entry->getParameters();
 828
 829                 wfRunHooks( 'LogLine', array( $type, $subtype, $title, $params,
 830                         &$this->comment, &$this->revert, $this->entry->getTimestamp() ) );
 831
 832                 return $this->revert;
 833         }
 834 }