includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine
   4  *
   5  * @file
   6  * @ingroup DifferenceEngine
   7  */
   8
   9 /**
  10  * Constant to indicate diff cache compatibility.
  11  * Bump this when changing the diff formatting in a way that
  12  * fixes important bugs or such to force cached diff views to
  13  * clear.
  14  */
  15 define( 'MW_DIFF_VERSION', '1.11a' );
  16
  17 /**
  18  * @todo document
  19  * @ingroup DifferenceEngine
  20  */
  21 class DifferenceEngine extends ContextSource {
  22         /**#@+
  23          * @private
  24          */
  25         var $mOldid, $mNewid;
  26         var $mOldContent, $mNewContent;
  27         protected $mDiffLang;
  28
  29         /**
  30          * @var Title
  31          */
  32         var $mOldPage, $mNewPage;
  33         var $mRcidMarkPatrolled;
  34
  35         /**
  36          * @var Revision
  37          */
  38         var $mOldRev, $mNewRev;
  39         private $mRevisionsIdsLoaded = false; // Have the revisions IDs been loaded
  40         var $mRevisionsLoaded = false; // Have the revisions been loaded
  41         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  42         var $mCacheHit = false; // Was the diff fetched from cache?
  43
  44         /**
  45          * Set this to true to add debug info to the HTML output.
  46          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  47          * (bug 20601)
  48          */
  49         var $enableDebugComment = false;
  50
  51         // If true, line X is not displayed when X is 1, for example to increase
  52         // readability and conserve space with many small diffs.
  53         protected $mReducedLineNumbers = false;
  54
  55         // Link to action=markpatrolled
  56         protected $mMarkPatrolledLink = null;
  57
  58         protected $unhide = false; # show rev_deleted content if allowed
  59         /**#@-*/
  60
  61         /**
  62          * Constructor
  63          * @param $context IContextSource context to use, anything else will be ignored
  64          * @param $old Integer old ID we want to show and diff with.
  65          * @param $new String either 'prev' or 'next'.
  66          * @param $rcid Integer ??? FIXME (default 0)
  67          * @param $refreshCache boolean If set, refreshes the diff cache
  68          * @param $unhide boolean If set, allow viewing deleted revs
  69          */
  70         function __construct( $context = null, $old = 0, $new = 0, $rcid = 0,
  71                 $refreshCache = false, $unhide = false )
  72         {
  73                 if ( $context instanceof IContextSource ) {
  74                         $this->setContext( $context );
  75                 }
  76
  77                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  78
  79                 $this->mOldid = $old;
  80                 $this->mNewid = $new;
  81                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  82                 $this->mRefreshCache = $refreshCache;
  83                 $this->unhide = $unhide;
  84         }
  85
  86         /**
  87          * @param $value bool
  88          */
  89         function setReducedLineNumbers( $value = true ) {
  90                 $this->mReducedLineNumbers = $value;
  91         }
  92
  93         /**
  94          * @return Language
  95          */
  96         function getDiffLang() {
  97                 if ( $this->mDiffLang === null ) {
  98                         # Default language in which the diff text is written.
  99                         $this->mDiffLang = $this->getTitle()->getPageLanguage();
 100                 }
 101                 return $this->mDiffLang;
 102         }
 103
 104         /**
 105          * @return bool
 106          */
 107         function wasCacheHit() {
 108                 return $this->mCacheHit;
 109         }
 110
 111         /**
 112          * @return int
 113          */
 114         function getOldid() {
 115                 $this->loadRevisionIds();
 116                 return $this->mOldid;
 117         }
 118
 119         /**
 120          * @return Bool|int
 121          */
 122         function getNewid() {
 123                 $this->loadRevisionIds();
 124                 return $this->mNewid;
 125         }
 126
 127         /**
 128          * Look up a special:Undelete link to the given deleted revision id,
 129          * as a workaround for being unable to load deleted diffs in currently.
 130          *
 131          * @param int $id revision ID
 132          * @return mixed URL or false
 133          */
 134         function deletedLink( $id ) {
 135                 if ( $this->getUser()->isAllowed( 'deletedhistory' ) ) {
 136                         $dbr = wfGetDB( DB_SLAVE );
 137                         $row = $dbr->selectRow('archive', '*',
 138                                 array( 'ar_rev_id' => $id ),
 139                                 __METHOD__ );
 140                         if ( $row ) {
 141                                 $rev = Revision::newFromArchiveRow( $row );
 142                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 143                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 144                                         'target' => $title->getPrefixedText(),
 145                                         'timestamp' => $rev->getTimestamp()
 146                                 ));
 147                         }
 148                 }
 149                 return false;
 150         }
 151
 152         /**
 153          * Build a wikitext link toward a deleted revision, if viewable.
 154          *
 155          * @param int $id revision ID
 156          * @return string wikitext fragment
 157          */
 158         function deletedIdMarker( $id ) {
 159                 $link = $this->deletedLink( $id );
 160                 if ( $link ) {
 161                         return "[$link $id]";
 162                 } else {
 163                         return $id;
 164                 }
 165         }
 166
 167         function showDiffPage( $diffOnly = false ) {
 168                 wfProfileIn( __METHOD__ );
 169
 170                 # Allow frames except in certain special cases
 171                 $out = $this->getOutput();
 172                 $out->allowClickjacking();
 173                 $out->setRobotPolicy( 'noindex,nofollow' );
 174
 175                 if ( !$this->loadRevisionData() ) {
 176                         // Sounds like a deleted revision... Let's see what we can do.
 177                         $t = $this->getTitle()->getPrefixedText();
 178                         $d = $this->msg( 'missingarticle-diff',
 179                                 $this->deletedIdMarker( $this->mOldid ),
 180                                 $this->deletedIdMarker( $this->mNewid ) )->escaped();
 181                         $out->setPageTitle( $this->msg( 'errorpagetitle' ) );
 182                         $out->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 183                         wfProfileOut( __METHOD__ );
 184                         return;
 185                 }
 186
 187                 $user = $this->getUser();
 188                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $user );
 189                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 190                         $permErrors = wfMergeErrorArrays( $permErrors,
 191                                 $this->mOldPage->getUserPermissionsErrors( 'read', $user ) );
 192                 }
 193                 if ( count( $permErrors ) ) {
 194                         wfProfileOut( __METHOD__ );
 195                         throw new PermissionsError( 'read', $permErrors );
 196                 }
 197
 198                 # If external diffs are enabled both globally and for the user,
 199                 # we'll use the application/x-external-editor interface to call
 200                 # an external diff tool like kompare, kdiff3, etc.
 201                 if ( ExternalEdit::useExternalEngine( $this->getContext(), 'diff' ) ) {
 202                         $urls = array(
 203                                 'File' => array( 'Extension' => 'wiki', 'URL' =>
 204                                         # This should be mOldPage, but it may not be set, see below.
 205                                         $this->mNewPage->getCanonicalURL( array(
 206                                                 'action' => 'raw', 'oldid' => $this->mOldid ) )
 207                                 ),
 208                                 'File2' => array( 'Extension' => 'wiki', 'URL' =>
 209                                         $this->mNewPage->getCanonicalURL( array(
 210                                                 'action' => 'raw', 'oldid' => $this->mNewid ) )
 211                                 ),
 212                         );
 213
 214                         $externalEditor = new ExternalEdit( $this->getContext(), $urls );
 215                         $externalEditor->execute();
 216
 217                         wfProfileOut( __METHOD__ );
 218                         return;
 219                 }
 220
 221                 $rollback = '';
 222                 $undoLink = '';
 223
 224                 $query = array();
 225                 # Carry over 'diffonly' param via navigation links
 226                 if ( $diffOnly != $user->getBoolOption( 'diffonly' ) ) {
 227                         $query['diffonly'] = $diffOnly;
 228                 }
 229                 # Cascade unhide param in links for easy deletion browsing
 230                 if ( $this->unhide ) {
 231                         $query['unhide'] = 1;
 232                 }
 233
 234                 # Check if one of the revisions is deleted/suppressed
 235                 $deleted = $suppressed = false;
 236                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT, $user );
 237
 238                 # mOldRev is false if the difference engine is called with a "vague" query for
 239                 # a diff between a version V and its previous version V' AND the version V
 240                 # is the first version of that article. In that case, V' does not exist.
 241                 if ( $this->mOldRev === false ) {
 242                         $out->setPageTitle( $this->mNewPage->getPrefixedText() );
 243                         $out->addSubtitle( $this->msg( 'difference' ) );
 244                         $samePage = true;
 245                         $oldHeader = '';
 246                 } else {
 247                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 248
 249                         $sk = $this->getSkin();
 250                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 251                                 $sk->suppressQuickbar();
 252                         }
 253
 254                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 255                                 $out->setPageTitle( $this->mNewPage->getPrefixedText() );
 256                                 $out->addSubtitle( $this->msg( 'difference' ) );
 257                                 $samePage = true;
 258                         } else {
 259                                 $out->setPageTitle( $this->mOldPage->getPrefixedText() . ', ' . $this->mNewPage->getPrefixedText() );
 260                                 $out->addSubtitle( $this->msg( 'difference-multipage' ) );
 261                                 $samePage = false;
 262                         }
 263
 264                         if ( $samePage && $this->mNewPage->quickUserCan( 'edit', $user ) ) {
 265                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback', $user ) ) {
 266                                         $out->preventClickjacking();
 267                                         $rollback = '&#160;&#160;&#160;' . Linker::generateRollback( $this->mNewRev );
 268                                 }
 269                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 270                                         $undoLink = ' ' . $this->msg( 'parentheses' )->rawParams(
 271                                                 Html::element( 'a', array(
 272                                                         'href' => $this->mNewPage->getLocalUrl( array(
 273                                                                 'action' => 'edit',
 274                                                                 'undoafter' => $this->mOldid,
 275                                                                 'undo' => $this->mNewid ) ),
 276                                                         'title' => Linker::titleAttrib( 'undo' )
 277                                                 ),
 278                                                 $this->msg( 'editundo' )->text()
 279                                         ) )->escaped();
 280                                 }
 281                         }
 282
 283                         # Make "previous revision link"
 284                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 285                                 $prevlink = Linker::linkKnown(
 286                                         $this->mOldPage,
 287                                         $this->msg( 'previousdiff' )->escaped(),
 288                                         array( 'id' => 'differences-prevlink' ),
 289                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 290                                 );
 291                         } else {
 292                                 $prevlink = '&#160;';
 293                         }
 294
 295                         if ( $this->mOldRev->isMinor() ) {
 296                                 $oldminor = ChangesList::flag( 'minor' );
 297                         } else {
 298                                 $oldminor = '';
 299                         }
 300
 301                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 302                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 303
 304                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 305                                 '<div id="mw-diff-otitle2">' .
 306                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 307                                 '<div id="mw-diff-otitle3">' . $oldminor .
 308                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 309                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 310
 311                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 312                                 $deleted = true; // old revisions text is hidden
 313                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 314                                         $suppressed = true; // also suppressed
 315                                 }
 316                         }
 317
 318                         # Check if this user can see the revisions
 319                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT, $user ) ) {
 320                                 $allowed = false;
 321                         }
 322                 }
 323
 324                 # Make "next revision link"
 325                 # Skip next link on the top revision
 326                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 327                         $nextlink = Linker::linkKnown(
 328                                 $this->mNewPage,
 329                                 $this->msg( 'nextdiff' )->escaped(),
 330                                 array( 'id' => 'differences-nextlink' ),
 331                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 332                         );
 333                 } else {
 334                         $nextlink = '&#160;';
 335                 }
 336
 337                 if ( $this->mNewRev->isMinor() ) {
 338                         $newminor = ChangesList::flag( 'minor' );
 339                 } else {
 340                         $newminor = '';
 341                 }
 342
 343                 # Handle RevisionDelete links...
 344                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 345                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 346
 347                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 348                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 349                                 " $rollback</div>" .
 350                         '<div id="mw-diff-ntitle3">' . $newminor .
 351                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 352                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 353
 354                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 355                         $deleted = true; // new revisions text is hidden
 356                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 357                                 $suppressed = true; // also suppressed
 358                 }
 359
 360                 # If the diff cannot be shown due to a deleted revision, then output
 361                 # the diff header and links to unhide (if available)...
 362                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 363                         $this->showDiffStyle();
 364                         $multi = $this->getMultiNotice();
 365                         $out->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 366                         if ( !$allowed ) {
 367                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 368                                 # Give explanation for why revision is not visible
 369                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 370                                         array( $msg ) );
 371                         } else {
 372                                 # Give explanation and add a link to view the diff...
 373                                 $link = $this->getTitle()->getFullUrl( $this->getRequest()->appendQueryValue( 'unhide', '1', true ) );
 374                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 375                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 376                         }
 377                 # Otherwise, output a regular diff...
 378                 } else {
 379                         # Add deletion notice if the user is viewing deleted content
 380                         $notice = '';
 381                         if ( $deleted ) {
 382                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 383                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . $this->msg( $msg )->parse() . "</div>\n";
 384                         }
 385                         $this->showDiff( $oldHeader, $newHeader, $notice );
 386                         if ( !$diffOnly ) {
 387                                 $this->renderNewRevision();
 388                         }
 389                 }
 390                 wfProfileOut( __METHOD__ );
 391         }
 392
 393         /**
 394          * Get a link to mark the change as patrolled, or '' if there's either no
 395          * revision to patrol or the user is not allowed to to it.
 396          * Side effect: this method will call OutputPage::preventClickjacking()
 397          * when a link is builded.
 398          *
 399          * @return String
 400          */
 401         protected function markPatrolledLink() {
 402                 global $wgUseRCPatrol;
 403
 404                 if ( $this->mMarkPatrolledLink === null ) {
 405                         // Prepare a change patrol link, if applicable
 406                         if ( $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) ) {
 407                                 // If we've been given an explicit change identifier, use it; saves time
 408                                 if ( $this->mRcidMarkPatrolled ) {
 409                                         $rcid = $this->mRcidMarkPatrolled;
 410                                         $rc = RecentChange::newFromId( $rcid );
 411                                         // Already patrolled?
 412                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 413                                 } else {
 414                                         // Look for an unpatrolled change corresponding to this diff
 415                                         $db = wfGetDB( DB_SLAVE );
 416                                         $change = RecentChange::newFromConds(
 417                                                 array(
 418                                                 // Redundant user,timestamp condition so we can use the existing index
 419                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 420                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 421                                                         'rc_this_oldid' => $this->mNewid,
 422                                                         'rc_last_oldid' => $this->mOldid,
 423                                                         'rc_patrolled'  => 0
 424                                                 ),
 425                                                 __METHOD__
 426                                         );
 427                                         if ( $change instanceof RecentChange ) {
 428                                                 $rcid = $change->mAttribs['rc_id'];
 429                                                 $this->mRcidMarkPatrolled = $rcid;
 430                                         } else {
 431                                                 // None found
 432                                                 $rcid = 0;
 433                                         }
 434                                 }
 435                                 // Build the link
 436                                 if ( $rcid ) {
 437                                         $this->getOutput()->preventClickjacking();
 438                                         $token = $this->getUser()->getEditToken( $rcid );
 439                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 440                                                 $this->mNewPage,
 441                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 442                                                 array(),
 443                                                 array(
 444                                                         'action' => 'markpatrolled',
 445                                                         'rcid' => $rcid,
 446                                                         'token' => $token,
 447                                                 )
 448                                         ) . ']</span>';
 449                                 } else {
 450                                         $this->mMarkPatrolledLink = '';
 451                                 }
 452                         } else {
 453                                 $this->mMarkPatrolledLink = '';
 454                         }
 455                 }
 456
 457                 return $this->mMarkPatrolledLink;
 458         }
 459
 460         /**
 461          * @param $rev Revision
 462          * @return String
 463          */
 464         protected function revisionDeleteLink( $rev ) {
 465                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 466                 if ( $link !== '' ) {
 467                         $link = '&#160;&#160;&#160;' . $link . ' ';
 468                 }
 469                 return $link;
 470         }
 471
 472         /**
 473          * Show the new revision of the page.
 474          */
 475         function renderNewRevision() {
 476                 wfProfileIn( __METHOD__ );
 477                 $out = $this->getOutput();
 478                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 479                 # Add "current version as of X" title
 480                 $out->addHTML( "<hr class='diff-hr' />
 481                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 482                 # Page content may be handled by a hooked call instead...
 483                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 484                         $this->loadNewText();
 485                         $out->setRevisionId( $this->mNewid );
 486                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 487                         $out->setArticleFlag( true );
 488
 489                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) { #NOTE: only needed for B/C: custom rendering of JS/CSS via hook
 490                                 // Stolen from Article::view --AG 2007-10-11
 491                                 // Give hooks a chance to customise the output
 492                                 // @TODO: standardize this crap into one function
 493                                 if ( !Hook::isRegistered( 'ShowRawCssJs' )
 494                     || wfRunHooks( 'ShowRawCssJs', array( ContentHandler::getContentText( $this->mNewContent ), $this->mNewPage, $out ) ) ) { #NOTE: deperecated hook, B/C only
 495                     // use the content object's own rendering
 496                     $po = $this->mContentObject->getParserOutput();
 497                     $out->addHTML( $po->getText() );
 498                                 }
 499             } elseif( !wfRunHooks( 'ArticleContentViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 500                 // Handled by extension
 501             } elseif( Hooks::isRegistered( 'ArticleViewCustom' )
 502                     && !wfRunHooks( 'ArticleViewCustom', array( ContentHandler::getContentText( $this->mNewContent ), $this->mNewPage, $out ) ) ) { #NOTE: deperecated hook, B/C only
 503                 // Handled by extension
 504                         } else {
 505                                 // Normal page
 506                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 507                                         // If the Title stored in the context is the same as the one
 508                                         // of the new revision, we can use its associated WikiPage
 509                                         // object.
 510                                         $wikiPage = $this->getWikiPage();
 511                                 } else {
 512                                         // Otherwise we need to create our own WikiPage object
 513                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 514                                 }
 515
 516                                 $parserOptions = ParserOptions::newFromContext( $this->getContext() );
 517                                 $parserOptions->enableLimitReport();
 518                                 $parserOptions->setTidy( true );
 519
 520                                 if ( !$this->mNewRev->isCurrent() ) {
 521                                         $parserOptions->setEditSection( false );
 522                                 }
 523
 524                                 $parserOutput = $wikiPage->getParserOutput( $parserOptions, $this->mNewid );
 525
 526                                 # WikiPage::getParserOutput() should not return false, but just in case
 527                                 if( $parserOutput ) {
 528                                         $out->addParserOutput( $parserOutput );
 529                                 }
 530                         }
 531                 }
 532                 # Add redundant patrol link on bottom...
 533                 $out->addHTML( $this->markPatrolledLink() );
 534
 535                 wfProfileOut( __METHOD__ );
 536         }
 537
 538         /**
 539          * Get the diff text, send it to the OutputPage object
 540          * Returns false if the diff could not be generated, otherwise returns true
 541          *
 542          * @return bool
 543          */
 544         function showDiff( $otitle, $ntitle, $notice = '' ) {
 545                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 546                 if ( $diff === false ) {
 547                         $this->getOutput()->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 548                         return false;
 549                 } else {
 550                         $this->showDiffStyle();
 551                         $this->getOutput()->addHTML( $diff );
 552                         return true;
 553                 }
 554         }
 555
 556         /**
 557          * Add style sheets and supporting JS for diff display.
 558          */
 559         function showDiffStyle() {
 560                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 561         }
 562
 563         /**
 564          * Get complete diff table, including header
 565          *
 566          * @param $otitle Title: old title
 567          * @param $ntitle Title: new title
 568          * @param $notice String: HTML between diff header and body
 569          * @return mixed
 570          */
 571         function getDiff( $otitle, $ntitle, $notice = '' ) {
 572                 $body = $this->getDiffBody();
 573                 if ( $body === false ) {
 574                         return false;
 575                 } else {
 576                         $multi = $this->getMultiNotice();
 577                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 578                 }
 579         }
 580
 581         /**
 582          * Get the diff table body, without header
 583          *
 584          * @return mixed (string/false)
 585          */
 586         public function getDiffBody() {
 587                 global $wgMemc;
 588                 wfProfileIn( __METHOD__ );
 589                 $this->mCacheHit = true;
 590                 // Check if the diff should be hidden from this user
 591                 if ( !$this->loadRevisionData() ) {
 592                         wfProfileOut( __METHOD__ );
 593                         return false;
 594                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 595                         wfProfileOut( __METHOD__ );
 596                         return false;
 597                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 598                         wfProfileOut( __METHOD__ );
 599                         return false;
 600                 }
 601                 // Short-circuit
 602                 // If mOldRev is false, it means that the
 603                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 604                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 605                 {
 606                         wfProfileOut( __METHOD__ );
 607                         return '';
 608                 }
 609                 // Cacheable?
 610                 $key = false;
 611                 if ( $this->mOldid && $this->mNewid ) {
 612                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 613                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 614                         // Try cache
 615                         if ( !$this->mRefreshCache ) {
 616                                 $difftext = $wgMemc->get( $key );
 617                                 if ( $difftext ) {
 618                                         wfIncrStats( 'diff_cache_hit' );
 619                                         $difftext = $this->localiseLineNumbers( $difftext );
 620                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 621                                         wfProfileOut( __METHOD__ );
 622                                         return $difftext;
 623                                 }
 624                         } // don't try to load but save the result
 625                 }
 626                 $this->mCacheHit = false;
 627
 628                 // Loadtext is permission safe, this just clears out the diff
 629                 if ( !$this->loadText() ) {
 630                         wfProfileOut( __METHOD__ );
 631                         return false;
 632                 }
 633
 634         #TODO: make sure both Content objects have the same content model. What do we do if they don't?
 635
 636                 $difftext = $this->generateContentDiffBody( $this->mOldContent, $this->mNewContent );
 637
 638                 // Save to cache for 7 days
 639                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 640                         wfIncrStats( 'diff_uncacheable' );
 641                 } elseif ( $key !== false && $difftext !== false ) {
 642                         wfIncrStats( 'diff_cache_miss' );
 643                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 644                 } else {
 645                         wfIncrStats( 'diff_uncacheable' );
 646                 }
 647                 // Replace line numbers with the text in the user's language
 648                 if ( $difftext !== false ) {
 649                         $difftext = $this->localiseLineNumbers( $difftext );
 650                 }
 651                 wfProfileOut( __METHOD__ );
 652                 return $difftext;
 653         }
 654
 655         /**
 656          * Make sure the proper modules are loaded before we try to
 657          * make the diff
 658          */
 659         private function initDiffEngines() {
 660                 global $wgExternalDiffEngine;
 661                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 662                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 663                         wfDl( 'php_wikidiff' );
 664                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 665                 }
 666                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 667                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 668                         wfDl( 'wikidiff2' );
 669                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 670                 }
 671         }
 672
 673     /**
 674      * Generate a diff, no caching.
 675      *
 676      * Subclasses may override this to provide a
 677      *
 678      * @param $old Content: old content
 679      * @param $new Content: new content
 680      *
 681      * @since 1.WD
 682      */
 683     function generateContentDiffBody( Content $old, Content $new ) {
 684         #XXX: generate a warning if $old or $new are not instances of TextContent?
 685         #XXX: fail if $old and $new don't have the same content model? or what?
 686
 687         $otext = $old->serialize();
 688         $ntext = $new->serialize();
 689
 690         #XXX: text should be "already segmented". what does that mean?
 691         return $this->generateTextDiffBody( $otext, $ntext );
 692     }
 693
 694     /**
 695      * Generate a diff, no caching
 696      *
 697      * @param $otext String: old text, must be already segmented
 698      * @param $ntext String: new text, must be already segmented
 699      * @deprecated since 1.WD, use generateContentDiffBody() instead!
 700      */
 701     function generateDiffBody( $otext, $ntext ) {
 702         wfDeprecated( __METHOD__, "1.WD" );
 703
 704         return $this->generateTextDiffBody( $otext, $ntext );
 705     }
 706
 707         /**
 708          * Generate a diff, no caching
 709          *
 710      * @todo move this to TextDifferenceEngine, make DifferenceEngine abstract. At some point.
 711      *
 712          * @param $otext String: old text, must be already segmented
 713          * @param $ntext String: new text, must be already segmented
 714          * @return bool|string
 715          */
 716         function generateTextDiffBody( $otext, $ntext ) {
 717                 global $wgExternalDiffEngine, $wgContLang;
 718
 719                 wfProfileIn( __METHOD__ );
 720
 721                 $otext = str_replace( "\r\n", "\n", $otext );
 722                 $ntext = str_replace( "\r\n", "\n", $ntext );
 723
 724                 $this->initDiffEngines();
 725
 726                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 727                         # For historical reasons, external diff engine expects
 728                         # input text to be HTML-escaped already
 729                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 730                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 731                         wfProfileOut( __METHOD__ );
 732                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 733                         $this->debug( 'wikidiff1' );
 734                 }
 735
 736                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 737                         # Better external diff engine, the 2 may some day be dropped
 738                         # This one does the escaping and segmenting itself
 739                         wfProfileIn( 'wikidiff2_do_diff' );
 740                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 741                         $text .= $this->debug( 'wikidiff2' );
 742                         wfProfileOut( 'wikidiff2_do_diff' );
 743                         wfProfileOut( __METHOD__ );
 744                         return $text;
 745                 }
 746                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 747                         # Diff via the shell
 748                         global $wgTmpDirectory;
 749                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 750                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 751
 752                         $tempFile1 = fopen( $tempName1, "w" );
 753                         if ( !$tempFile1 ) {
 754                                 wfProfileOut( __METHOD__ );
 755                                 return false;
 756                         }
 757                         $tempFile2 = fopen( $tempName2, "w" );
 758                         if ( !$tempFile2 ) {
 759                                 wfProfileOut( __METHOD__ );
 760                                 return false;
 761                         }
 762                         fwrite( $tempFile1, $otext );
 763                         fwrite( $tempFile2, $ntext );
 764                         fclose( $tempFile1 );
 765                         fclose( $tempFile2 );
 766                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 767                         wfProfileIn( __METHOD__ . "-shellexec" );
 768                         $difftext = wfShellExec( $cmd );
 769                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 770                         wfProfileOut( __METHOD__ . "-shellexec" );
 771                         unlink( $tempName1 );
 772                         unlink( $tempName2 );
 773                         wfProfileOut( __METHOD__ );
 774                         return $difftext;
 775                 }
 776
 777                 # Native PHP diff
 778                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 779                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 780                 $diffs = new Diff( $ota, $nta );
 781                 $formatter = new TableDiffFormatter();
 782                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 783                 wfProfileOut( __METHOD__ );
 784                 return $difftext;
 785         }
 786
 787         /**
 788          * Generate a debug comment indicating diff generating time,
 789          * server node, and generator backend.
 790          * @return string
 791          */
 792         protected function debug( $generator = "internal" ) {
 793                 global $wgShowHostnames;
 794                 if ( !$this->enableDebugComment ) {
 795                         return '';
 796                 }
 797                 $data = array( $generator );
 798                 if ( $wgShowHostnames ) {
 799                         $data[] = wfHostname();
 800                 }
 801                 $data[] = wfTimestamp( TS_DB );
 802                 return "<!-- diff generator: " .
 803                 implode( " ",
 804                 array_map(
 805                                         "htmlspecialchars",
 806                 $data ) ) .
 807                         " -->\n";
 808         }
 809
 810         /**
 811          * Replace line numbers with the text in the user's language
 812          * @return mixed
 813          */
 814         function localiseLineNumbers( $text ) {
 815                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 816                 array( &$this, 'localiseLineNumbersCb' ), $text );
 817         }
 818
 819         function localiseLineNumbersCb( $matches ) {
 820                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 821                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 822         }
 823
 824
 825         /**
 826          * If there are revisions between the ones being compared, return a note saying so.
 827          * @return string
 828          */
 829         function getMultiNotice() {
 830                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 831                         return '';
 832                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 833                         // Comparing two different pages? Count would be meaningless.
 834                         return '';
 835                 }
 836
 837                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 838                         $oldRev = $this->mNewRev; // flip
 839                         $newRev = $this->mOldRev; // flip
 840                 } else { // normal case
 841                         $oldRev = $this->mOldRev;
 842                         $newRev = $this->mNewRev;
 843                 }
 844
 845                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 846                 if ( $nEdits > 0 ) {
 847                         $limit = 100; // use diff-multi-manyusers if too many users
 848                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 849                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 850                 }
 851                 return ''; // nothing
 852         }
 853
 854         /**
 855          * Get a notice about how many intermediate edits and users there are
 856          * @param $numEdits int
 857          * @param $numUsers int
 858          * @param $limit int
 859          * @return string
 860          */
 861         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 862                 if ( $numUsers > $limit ) {
 863                         $msg = 'diff-multi-manyusers';
 864                         $numUsers = $limit;
 865                 } else {
 866                         $msg = 'diff-multi';
 867                 }
 868                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 869         }
 870
 871         /**
 872          * Get a header for a specified revision.
 873          *
 874          * @param $rev Revision
 875          * @param $complete String: 'complete' to get the header wrapped depending
 876          *        the visibility of the revision and a link to edit the page.
 877          * @return String HTML fragment
 878          */
 879         private function getRevisionHeader( Revision $rev, $complete = '' ) {
 880                 $lang = $this->getLanguage();
 881                 $user = $this->getUser();
 882                 $revtimestamp = $rev->getTimestamp();
 883                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 884                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 885                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 886
 887                 $header = $this->msg(
 888                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 889                         $timestamp,
 890                         $dateofrev,
 891                         $timeofrev
 892                 )->escaped();
 893
 894                 if ( $complete !== 'complete' ) {
 895                         return $header;
 896                 }
 897
 898                 $title = $rev->getTitle();
 899
 900                 $header = Linker::linkKnown( $title, $header, array(),
 901                         array( 'oldid' => $rev->getID() ) );
 902
 903                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 904                         $editQuery = array( 'action' => 'edit' );
 905                         if ( !$rev->isCurrent() ) {
 906                                 $editQuery['oldid'] = $rev->getID();
 907                         }
 908
 909                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 910                         $header .= ' (' . Linker::linkKnown( $title, $msg, array(), $editQuery ) . ')';
 911                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 912                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 913                         }
 914                 } else {
 915                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 916                 }
 917
 918                 return $header;
 919         }
 920
 921         /**
 922          * Add the header to a diff body
 923          *
 924          * @return string
 925          */
 926         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 927                 // shared.css sets diff in interface language/dir, but the actual content
 928                 // is often in a different language, mostly the page content language/dir
 929                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 930                 $header = "<table class='$tableClass'>";
 931
 932                 if ( !$diff && !$otitle ) {
 933                         $header .= "
 934                         <tr valign='top'>
 935                         <td class='diff-ntitle'>{$ntitle}</td>
 936                         </tr>";
 937                         $multiColspan = 1;
 938                 } else {
 939                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 940                                 $header .= "
 941                                 <col class='diff-marker' />
 942                                 <col class='diff-content' />
 943                                 <col class='diff-marker' />
 944                                 <col class='diff-content' />";
 945                                 $colspan = 2;
 946                                 $multiColspan = 4;
 947                         } else {
 948                                 $colspan = 1;
 949                                 $multiColspan = 2;
 950                         }
 951                         $header .= "
 952                         <tr valign='top'>
 953                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 954                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 955                         </tr>";
 956                 }
 957
 958                 if ( $multi != '' ) {
 959                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 960                 }
 961                 if ( $notice != '' ) {
 962                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 963                 }
 964
 965                 return $header . $diff . "</table>";
 966         }
 967
 968         /**
 969          * Use specified text instead of loading from the database
 970      * @deprecated since 1.WD
 971          */
 972         function setText( $oldText, $newText ) { #FIXME: no longer use this, use setContent()!
 973         wfDeprecated( __METHOD__, "1.WD" );
 974
 975         $oldContent = ContentHandler::makeContent( $oldText, $this->getTitle() );
 976         $newContent = ContentHandler::makeContent( $newText, $this->getTitle() );
 977
 978         $this->setContent( $oldContent, $newContent );
 979     }
 980
 981     /**
 982      * Use specified text instead of loading from the database
 983      * @since 1.WD
 984      */
 985     function setContent( Content $oldContent, Content $newContent ) {
 986         $this->mOldContent = $oldContent;
 987         $this->mNewContent = $newContent;
 988
 989         $this->mTextLoaded = 2;
 990         $this->mRevisionsLoaded = true;
 991     }
 992
 993         /**
 994          * Set the language in which the diff text is written
 995          * (Defaults to page content language).
 996          * @since 1.19
 997          */
 998         function setTextLanguage( $lang ) {
 999                 $this->mDiffLang = wfGetLangObj( $lang );
1000         }
1001
1002         /**
1003          * Load revision IDs
1004          */
1005         private function loadRevisionIds() {
1006                 if ( $this->mRevisionsIdsLoaded ) {
1007                         return;
1008                 }
1009
1010                 $this->mRevisionsIdsLoaded = true;
1011
1012                 $old = $this->mOldid;
1013                 $new = $this->mNewid;
1014
1015                 if ( $new === 'prev' ) {
1016                         # Show diff between revision $old and the previous one.
1017                         # Get previous one from DB.
1018                         $this->mNewid = intval( $old );
1019                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
1020                 } elseif ( $new === 'next' ) {
1021                         # Show diff between revision $old and the next one.
1022                         # Get next one from DB.
1023                         $this->mOldid = intval( $old );
1024                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
1025                         if ( $this->mNewid === false ) {
1026                                 # if no result, NewId points to the newest old revision. The only newer
1027                                 # revision is cur, which is "0".
1028                                 $this->mNewid = 0;
1029                         }
1030                 } else {
1031                         $this->mOldid = intval( $old );
1032                         $this->mNewid = intval( $new );
1033                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
1034                 }
1035         }
1036
1037         /**
1038          * Load revision metadata for the specified articles. If newid is 0, then compare
1039          * the old article in oldid to the current article; if oldid is 0, then
1040          * compare the current article to the immediately previous one (ignoring the
1041          * value of newid).
1042          *
1043          * If oldid is false, leave the corresponding revision object set
1044          * to false. This is impossible via ordinary user input, and is provided for
1045          * API convenience.
1046          *
1047          * @return bool
1048          */
1049         function loadRevisionData() {
1050                 if ( $this->mRevisionsLoaded ) {
1051                         return true;
1052                 }
1053
1054                 // Whether it succeeds or fails, we don't want to try again
1055                 $this->mRevisionsLoaded = true;
1056
1057                 $this->loadRevisionIds();
1058
1059                 // Load the new revision object
1060                 $this->mNewRev = $this->mNewid
1061                         ? Revision::newFromId( $this->mNewid )
1062                         : Revision::newFromTitle( $this->getTitle() );
1063
1064                 if ( !$this->mNewRev instanceof Revision ) {
1065                         return false;
1066                 }
1067
1068                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1069                 $this->mNewid = $this->mNewRev->getId();
1070                 $this->mNewPage = $this->mNewRev->getTitle();
1071
1072                 // Load the old revision object
1073                 $this->mOldRev = false;
1074                 if ( $this->mOldid ) {
1075                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1076                 } elseif ( $this->mOldid === 0 ) {
1077                         $rev = $this->mNewRev->getPrevious();
1078                         if ( $rev ) {
1079                                 $this->mOldid = $rev->getId();
1080                                 $this->mOldRev = $rev;
1081                         } else {
1082                                 // No previous revision; mark to show as first-version only.
1083                                 $this->mOldid = false;
1084                                 $this->mOldRev = false;
1085                         }
1086                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1087
1088                 if ( is_null( $this->mOldRev ) ) {
1089                         return false;
1090                 }
1091
1092                 if ( $this->mOldRev ) {
1093                         $this->mOldPage = $this->mOldRev->getTitle();
1094                 }
1095
1096                 return true;
1097         }
1098
1099         /**
1100          * Load the text of the revisions, as well as revision data.
1101          *
1102          * @return bool
1103          */
1104         function loadText() {
1105                 if ( $this->mTextLoaded == 2 ) {
1106                         return true;
1107                 } else {
1108                         // Whether it succeeds or fails, we don't want to try again
1109                         $this->mTextLoaded = 2;
1110                 }
1111
1112                 if ( !$this->loadRevisionData() ) {
1113                         return false;
1114                 }
1115                 if ( $this->mOldRev ) {
1116                         $this->mOldContent = $this->mOldRev->getContent( Revision::FOR_THIS_USER );
1117                         if ( $this->mOldContent === false ) {
1118                                 return false;
1119                         }
1120                 }
1121                 if ( $this->mNewRev ) {
1122                         $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER );
1123                         if ( $this->mNewContent === false ) {
1124                                 return false;
1125                         }
1126                 }
1127                 return true;
1128         }
1129
1130         /**
1131          * Load the text of the new revision, not the old one
1132          *
1133          * @return bool
1134          */
1135         function loadNewText() {
1136                 if ( $this->mTextLoaded >= 1 ) {
1137                         return true;
1138                 } else {
1139                         $this->mTextLoaded = 1;
1140                 }
1141                 if ( !$this->loadRevisionData() ) {
1142                         return false;
1143                 }
1144                 $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER );
1145                 return true;
1146         }
1147 }