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 {
  22         /**#@+
  23          * @private
  24          */
  25         var $mOldid, $mNewid;
  26         var $mOldtext, $mNewtext;
  27         protected $mDiffLang;
  28
  29         /**
  30          * @var Title
  31          */
  32         var $mOldPage, $mNewPage, $mTitle;
  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 $titleObj Title object that the diff is associated with
  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( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  71                 $refreshCache = false, $unhide = false )
  72         {
  73                 if ( $titleObj ) {
  74                         $this->mTitle = $titleObj;
  75                 } else {
  76                         global $wgTitle;
  77                         $this->mTitle = $wgTitle; // @TODO: get rid of this
  78                 }
  79                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  80
  81                 $this->mOldid = $old;
  82                 $this->mNewid = $new;
  83                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  84                 $this->mRefreshCache = $refreshCache;
  85                 $this->unhide = $unhide;
  86         }
  87
  88         /**
  89          * @param $value bool
  90          */
  91         function setReducedLineNumbers( $value = true ) {
  92                 $this->mReducedLineNumbers = $value;
  93         }
  94
  95         /**
  96          * @return Language
  97          */
  98         function getDiffLang() {
  99                 if ( $this->mDiffLang === null ) {
 100                         # Default language in which the diff text is written.
 101                         $this->mDiffLang = $this->mTitle->getPageLanguage();
 102                 }
 103                 return $this->mDiffLang;
 104         }
 105
 106         /**
 107          * @return Title
 108          */
 109         function getTitle() {
 110                 return $this->mTitle;
 111         }
 112
 113         /**
 114          * @return bool
 115          */
 116         function wasCacheHit() {
 117                 return $this->mCacheHit;
 118         }
 119
 120         /**
 121          * @return int
 122          */
 123         function getOldid() {
 124                 $this->loadRevisionIds();
 125                 return $this->mOldid;
 126         }
 127
 128         /**
 129          * @return Bool|int
 130          */
 131         function getNewid() {
 132                 $this->loadRevisionIds();
 133                 return $this->mNewid;
 134         }
 135
 136         /**
 137          * Look up a special:Undelete link to the given deleted revision id,
 138          * as a workaround for being unable to load deleted diffs in currently.
 139          *
 140          * @param int $id revision ID
 141          * @return mixed URL or false
 142          */
 143         function deletedLink( $id ) {
 144                 global $wgUser;
 145                 if ( $wgUser->isAllowed( 'deletedhistory' ) ) {
 146                         $dbr = wfGetDB( DB_SLAVE );
 147                         $row = $dbr->selectRow('archive', '*',
 148                                 array( 'ar_rev_id' => $id ),
 149                                 __METHOD__ );
 150                         if ( $row ) {
 151                                 $rev = Revision::newFromArchiveRow( $row );
 152                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 153                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 154                                         'target' => $title->getPrefixedText(),
 155                                         'timestamp' => $rev->getTimestamp()
 156                                 ));
 157                         }
 158                 }
 159                 return false;
 160         }
 161
 162         /**
 163          * Build a wikitext link toward a deleted revision, if viewable.
 164          *
 165          * @param int $id revision ID
 166          * @return string wikitext fragment
 167          */
 168         function deletedIdMarker( $id ) {
 169                 $link = $this->deletedLink( $id );
 170                 if ( $link ) {
 171                         return "[$link $id]";
 172                 } else {
 173                         return $id;
 174                 }
 175         }
 176
 177         function showDiffPage( $diffOnly = false ) {
 178                 global $wgUser, $wgOut, $wgRequest, $wgUseExternalEditor;
 179                 wfProfileIn( __METHOD__ );
 180
 181                 # Allow frames except in certain special cases
 182                 $wgOut->allowClickjacking();
 183                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 184
 185                 if ( !$this->loadRevisionData() ) {
 186                         // Sounds like a deleted revision... Let's see what we can do.
 187                         $t = $this->mTitle->getPrefixedText();
 188                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 189                                 $this->deletedIdMarker( $this->mOldid ),
 190                                 $this->deletedIdMarker( $this->mNewid ) );
 191                         $wgOut->setPageTitle( wfMessage( 'errorpagetitle' ) );
 192                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 193                         wfProfileOut( __METHOD__ );
 194                         return;
 195                 }
 196
 197                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $wgUser );
 198                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 199                         $permErrors = wfMergeErrorArrays( $permErrors,
 200                                 $this->mOldPage->getUserPermissionsErrors( 'read', $wgUser ) );
 201                 }
 202                 if ( count( $permErrors ) ) {
 203                         wfProfileOut( __METHOD__ );
 204                         throw new PermissionsError( 'read', $permErrors );
 205                 }
 206
 207                 # If external diffs are enabled both globally and for the user,
 208                 # we'll use the application/x-external-editor interface to call
 209                 # an external diff tool like kompare, kdiff3, etc.
 210                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 211                         global $wgCanonicalServer, $wgScript, $wgLang;
 212                         $wgOut->disable();
 213                         header ( "Content-type: application/x-external-editor; charset=UTF-8" );
 214                         # This should be mOldPage, but it may not be set, see below.
 215                         $url1 = $this->mNewPage->getCanonicalURL( array(
 216                                 'action' => 'raw',
 217                                 'oldid' => $this->mOldid
 218                         ) );
 219                         $url2 = $this->mNewPage->getCanonicalURL( array(
 220                                 'action' => 'raw',
 221                                 'oldid' => $this->mNewid
 222                         ) );
 223                         $special = $wgLang->getNsText( NS_SPECIAL );
 224                         $control = <<<CONTROL
 225                         [Process]
 226                         Type=Diff text
 227                         Engine=MediaWiki
 228                         Script={$wgCanonicalServer}{$wgScript}
 229                         Special namespace={$special}
 230
 231                         [File]
 232                         Extension=wiki
 233                         URL=$url1
 234
 235                         [File 2]
 236                         Extension=wiki
 237                         URL=$url2
 238 CONTROL;
 239                         echo( $control );
 240
 241                         wfProfileOut( __METHOD__ );
 242                         return;
 243                 }
 244
 245                 $rollback = '';
 246                 $undoLink = '';
 247
 248                 $query = array();
 249                 # Carry over 'diffonly' param via navigation links
 250                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 251                         $query['diffonly'] = $diffOnly;
 252                 }
 253                 # Cascade unhide param in links for easy deletion browsing
 254                 if ( $this->unhide ) {
 255                         $query['unhide'] = 1;
 256                 }
 257
 258                 # Check if one of the revisions is deleted/suppressed
 259                 $deleted = $suppressed = false;
 260                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT );
 261
 262                 # mOldRev is false if the difference engine is called with a "vague" query for
 263                 # a diff between a version V and its previous version V' AND the version V
 264                 # is the first version of that article. In that case, V' does not exist.
 265                 if ( $this->mOldRev === false ) {
 266                         $wgOut->setPageTitle( $this->mNewPage->getPrefixedText() );
 267                         $wgOut->addSubtitle( wfMessage( 'difference' ) );
 268                         $samePage = true;
 269                         $oldHeader = '';
 270                 } else {
 271                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 272
 273                         $sk = $wgUser->getSkin();
 274                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 275                                 $sk->suppressQuickbar();
 276                         }
 277
 278                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 279                                 $wgOut->setPageTitle( $this->mNewPage->getPrefixedText() );
 280                                 $wgOut->addSubtitle( wfMessage( 'difference' ) );
 281                                 $samePage = true;
 282                         } else {
 283                                 $wgOut->setPageTitle( $this->mOldPage->getPrefixedText() . ', ' . $this->mNewPage->getPrefixedText() );
 284                                 $wgOut->addSubtitle( wfMessage( 'difference-multipage' ) );
 285                                 $samePage = false;
 286                         }
 287
 288                         if ( $samePage && $this->mNewPage->userCan( 'edit' ) ) {
 289                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback' ) ) {
 290                                         $wgOut->preventClickjacking();
 291                                         $rollback = '&#160;&#160;&#160;' . Linker::generateRollback( $this->mNewRev );
 292                                 }
 293                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 294                                         $undoLink = ' ' . wfMsgHtml( 'parentheses', Html::element( 'a', array(
 295                                                 'href' => $this->mNewPage->getLocalUrl( array(
 296                                                         'action' => 'edit',
 297                                                         'undoafter' => $this->mOldid,
 298                                                         'undo' => $this->mNewid ) ),
 299                                                 'title' => Linker::titleAttrib( 'undo' )
 300                                         ), wfMsg( 'editundo' ) ) );
 301                                 }
 302                         }
 303
 304                         # Make "previous revision link"
 305                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 306                                 $prevlink = Linker::linkKnown(
 307                                         $this->mOldPage,
 308                                         wfMsgHtml( 'previousdiff' ),
 309                                         array( 'id' => 'differences-prevlink' ),
 310                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 311                                 );
 312                         } else {
 313                                 $prevlink = '&#160;';
 314                         }
 315
 316                         if ( $this->mOldRev->isMinor() ) {
 317                                 $oldminor = ChangesList::flag( 'minor' );
 318                         } else {
 319                                 $oldminor = '';
 320                         }
 321
 322                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 323                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 324
 325                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 326                                 '<div id="mw-diff-otitle2">' .
 327                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 328                                 '<div id="mw-diff-otitle3">' . $oldminor .
 329                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 330                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 331
 332                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 333                                 $deleted = true; // old revisions text is hidden
 334                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 335                                         $suppressed = true; // also suppressed
 336                                 }
 337                         }
 338
 339                         # Check if this user can see the revisions
 340                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 341                                 $allowed = false;
 342                         }
 343                 }
 344
 345                 # Make "next revision link"
 346                 # Skip next link on the top revision
 347                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 348                         $nextlink = Linker::linkKnown(
 349                                 $this->mNewPage,
 350                                 wfMsgHtml( 'nextdiff' ),
 351                                 array( 'id' => 'differences-nextlink' ),
 352                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 353                         );
 354                 } else {
 355                         $nextlink = '&#160;';
 356                 }
 357
 358                 if ( $this->mNewRev->isMinor() ) {
 359                         $newminor = ChangesList::flag( 'minor' );
 360                 } else {
 361                         $newminor = '';
 362                 }
 363
 364                 # Handle RevisionDelete links...
 365                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 366                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 367
 368                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 369                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 370                                 " $rollback</div>" .
 371                         '<div id="mw-diff-ntitle3">' . $newminor .
 372                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 373                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 374
 375                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 376                         $deleted = true; // new revisions text is hidden
 377                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 378                                 $suppressed = true; // also suppressed
 379                 }
 380
 381                 # If the diff cannot be shown due to a deleted revision, then output
 382                 # the diff header and links to unhide (if available)...
 383                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 384                         $this->showDiffStyle();
 385                         $multi = $this->getMultiNotice();
 386                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 387                         if ( !$allowed ) {
 388                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 389                                 # Give explanation for why revision is not visible
 390                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 391                                         array( $msg ) );
 392                         } else {
 393                                 # Give explanation and add a link to view the diff...
 394                                 $link = $this->mTitle->getFullUrl( $wgRequest->appendQueryValue( 'unhide', '1', true ) );
 395                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 396                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 397                         }
 398                 # Otherwise, output a regular diff...
 399                 } else {
 400                         # Add deletion notice if the user is viewing deleted content
 401                         $notice = '';
 402                         if ( $deleted ) {
 403                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 404                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 405                         }
 406                         $this->showDiff( $oldHeader, $newHeader, $notice );
 407                         if ( !$diffOnly ) {
 408                                 $this->renderNewRevision();
 409                         }
 410                 }
 411                 wfProfileOut( __METHOD__ );
 412         }
 413
 414         /**
 415          * Get a link to mark the change as patrolled, or '' if there's either no
 416          * revision to patrol or the user is not allowed to to it.
 417          * Side effect: this method will call OutputPage::preventClickjacking()
 418          * when a link is builded.
 419          *
 420          * @return String
 421          */
 422         protected function markPatrolledLink() {
 423                 global $wgUseRCPatrol, $wgUser, $wgOut;
 424
 425                 if ( $this->mMarkPatrolledLink === null ) {
 426                         // Prepare a change patrol link, if applicable
 427                         if ( $wgUseRCPatrol && $this->mNewPage->userCan( 'patrol' ) ) {
 428                                 // If we've been given an explicit change identifier, use it; saves time
 429                                 if ( $this->mRcidMarkPatrolled ) {
 430                                         $rcid = $this->mRcidMarkPatrolled;
 431                                         $rc = RecentChange::newFromId( $rcid );
 432                                         // Already patrolled?
 433                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 434                                 } else {
 435                                         // Look for an unpatrolled change corresponding to this diff
 436                                         $db = wfGetDB( DB_SLAVE );
 437                                         $change = RecentChange::newFromConds(
 438                                                 array(
 439                                                 // Redundant user,timestamp condition so we can use the existing index
 440                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 441                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 442                                                         'rc_this_oldid' => $this->mNewid,
 443                                                         'rc_last_oldid' => $this->mOldid,
 444                                                         'rc_patrolled'  => 0
 445                                                 ),
 446                                                 __METHOD__
 447                                         );
 448                                         if ( $change instanceof RecentChange ) {
 449                                                 $rcid = $change->mAttribs['rc_id'];
 450                                                 $this->mRcidMarkPatrolled = $rcid;
 451                                         } else {
 452                                                 // None found
 453                                                 $rcid = 0;
 454                                         }
 455                                 }
 456                                 // Build the link
 457                                 if ( $rcid ) {
 458                                         $wgOut->preventClickjacking();
 459                                         $token = $wgUser->editToken( $rcid );
 460                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 461                                                 $this->mNewPage,
 462                                                 wfMsgHtml( 'markaspatrolleddiff' ),
 463                                                 array(),
 464                                                 array(
 465                                                         'action' => 'markpatrolled',
 466                                                         'rcid' => $rcid,
 467                                                         'token' => $token,
 468                                                 )
 469                                         ) . ']</span>';
 470                                 } else {
 471                                         $this->mMarkPatrolledLink = '';
 472                                 }
 473                         } else {
 474                                 $this->mMarkPatrolledLink = '';
 475                         }
 476                 }
 477
 478                 return $this->mMarkPatrolledLink;
 479         }
 480
 481         /**
 482          * @param $rev Revision
 483          * @return String
 484          */
 485         protected function revisionDeleteLink( $rev ) {
 486                 global $wgUser;
 487                 $link = '';
 488                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 489                 // Show del/undel link if:
 490                 // (a) the user can delete revisions, or
 491                 // (b) the user can view deleted revision *and* this one is deleted
 492                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 493                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 494                                 $link = Linker::revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 495                         } else {
 496                                 $query = array(
 497                                         'type'   => 'revision',
 498                                         'target' => $rev->getTitle()->getPrefixedDBkey(),
 499                                         'ids'    => $rev->getId()
 500                                 );
 501                                 $link = Linker::revDeleteLink( $query,
 502                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 503                         }
 504                         $link = '&#160;&#160;&#160;' . $link . ' ';
 505                 }
 506                 return $link;
 507         }
 508
 509         /**
 510          * Show the new revision of the page.
 511          */
 512         function renderNewRevision() {
 513                 global $wgOut;
 514                 wfProfileIn( __METHOD__ );
 515                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 516                 # Add "current version as of X" title
 517                 $wgOut->addHTML( "<hr class='diff-hr' />
 518                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 519                 # Page content may be handled by a hooked call instead...
 520                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 521                         # Use the current version parser cache if applicable
 522                         $pCache = true;
 523                         if ( !$this->mNewRev->isCurrent() ) {
 524                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 525                                 $pCache = false;
 526                         }
 527
 528                         $this->loadNewText();
 529                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 530                         $wgOut->setArticleFlag( true );
 531
 532                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 533                                 // Stolen from Article::view --AG 2007-10-11
 534                                 // Give hooks a chance to customise the output
 535                                 // @TODO: standardize this crap into one function
 536                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mNewPage, $wgOut ) ) ) {
 537                                         // Wrap the whole lot in a <pre> and don't parse
 538                                         $m = array();
 539                                         preg_match( '!\.(css|js)$!u', $this->mNewPage->getText(), $m );
 540                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 541                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 542                                         $wgOut->addHTML( "\n</pre>\n" );
 543                                 }
 544                         } elseif ( $pCache ) {
 545                                 $article = new Article( $this->mNewPage, 0 );
 546                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 547                                 if( $pOutput ) {
 548                                         $wgOut->addParserOutput( $pOutput );
 549                                 } else {
 550                                         $article->doViewParse();
 551                                 }
 552                         } else {
 553                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 554                         }
 555
 556                         if ( !$this->mNewRev->isCurrent() ) {
 557                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 558                         }
 559                 }
 560                 # Add redundant patrol link on bottom...
 561                 $wgOut->addHTML( $this->markPatrolledLink() );
 562
 563                 wfProfileOut( __METHOD__ );
 564         }
 565
 566         /**
 567          * Get the diff text, send it to $wgOut
 568          * Returns false if the diff could not be generated, otherwise returns true
 569          *
 570          * @return bool
 571          */
 572         function showDiff( $otitle, $ntitle, $notice = '' ) {
 573                 global $wgOut;
 574                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 575                 if ( $diff === false ) {
 576                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 577                         return false;
 578                 } else {
 579                         $this->showDiffStyle();
 580                         $wgOut->addHTML( $diff );
 581                         return true;
 582                 }
 583         }
 584
 585         /**
 586          * Add style sheets and supporting JS for diff display.
 587          */
 588         function showDiffStyle() {
 589                 global $wgOut;
 590                 $wgOut->addModuleStyles( 'mediawiki.action.history.diff' );
 591         }
 592
 593         /**
 594          * Get complete diff table, including header
 595          *
 596          * @param $otitle Title: old title
 597          * @param $ntitle Title: new title
 598          * @param $notice String: HTML between diff header and body
 599          * @return mixed
 600          */
 601         function getDiff( $otitle, $ntitle, $notice = '' ) {
 602                 $body = $this->getDiffBody();
 603                 if ( $body === false ) {
 604                         return false;
 605                 } else {
 606                         $multi = $this->getMultiNotice();
 607                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 608                 }
 609         }
 610
 611         /**
 612          * Get the diff table body, without header
 613          *
 614          * @return mixed (string/false)
 615          */
 616         public function getDiffBody() {
 617                 global $wgMemc;
 618                 wfProfileIn( __METHOD__ );
 619                 $this->mCacheHit = true;
 620                 // Check if the diff should be hidden from this user
 621                 if ( !$this->loadRevisionData() ) {
 622                         wfProfileOut( __METHOD__ );
 623                         return false;
 624                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 625                         wfProfileOut( __METHOD__ );
 626                         return false;
 627                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 628                         wfProfileOut( __METHOD__ );
 629                         return false;
 630                 }
 631                 // Short-circuit
 632                 // If mOldRev is false, it means that the
 633                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 634                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 635                 {
 636                         wfProfileOut( __METHOD__ );
 637                         return '';
 638                 }
 639                 // Cacheable?
 640                 $key = false;
 641                 if ( $this->mOldid && $this->mNewid ) {
 642                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 643                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 644                         // Try cache
 645                         if ( !$this->mRefreshCache ) {
 646                                 $difftext = $wgMemc->get( $key );
 647                                 if ( $difftext ) {
 648                                         wfIncrStats( 'diff_cache_hit' );
 649                                         $difftext = $this->localiseLineNumbers( $difftext );
 650                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 651                                         wfProfileOut( __METHOD__ );
 652                                         return $difftext;
 653                                 }
 654                         } // don't try to load but save the result
 655                 }
 656                 $this->mCacheHit = false;
 657
 658                 // Loadtext is permission safe, this just clears out the diff
 659                 if ( !$this->loadText() ) {
 660                         wfProfileOut( __METHOD__ );
 661                         return false;
 662                 }
 663
 664                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 665
 666                 // Save to cache for 7 days
 667                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 668                         wfIncrStats( 'diff_uncacheable' );
 669                 } elseif ( $key !== false && $difftext !== false ) {
 670                         wfIncrStats( 'diff_cache_miss' );
 671                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 672                 } else {
 673                         wfIncrStats( 'diff_uncacheable' );
 674                 }
 675                 // Replace line numbers with the text in the user's language
 676                 if ( $difftext !== false ) {
 677                         $difftext = $this->localiseLineNumbers( $difftext );
 678                 }
 679                 wfProfileOut( __METHOD__ );
 680                 return $difftext;
 681         }
 682
 683         /**
 684          * Make sure the proper modules are loaded before we try to
 685          * make the diff
 686          */
 687         private function initDiffEngines() {
 688                 global $wgExternalDiffEngine;
 689                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 690                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 691                         wfDl( 'php_wikidiff' );
 692                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 693                 }
 694                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 695                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 696                         wfDl( 'wikidiff2' );
 697                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 698                 }
 699         }
 700
 701         /**
 702          * Generate a diff, no caching
 703          *
 704          * @param $otext String: old text, must be already segmented
 705          * @param $ntext String: new text, must be already segmented
 706          */
 707         function generateDiffBody( $otext, $ntext ) {
 708                 global $wgExternalDiffEngine, $wgContLang;
 709
 710                 wfProfileIn( __METHOD__ );
 711
 712                 $otext = str_replace( "\r\n", "\n", $otext );
 713                 $ntext = str_replace( "\r\n", "\n", $ntext );
 714
 715                 $this->initDiffEngines();
 716
 717                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 718                         # For historical reasons, external diff engine expects
 719                         # input text to be HTML-escaped already
 720                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 721                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 722                         wfProfileOut( __METHOD__ );
 723                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 724                         $this->debug( 'wikidiff1' );
 725                 }
 726
 727                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 728                         # Better external diff engine, the 2 may some day be dropped
 729                         # This one does the escaping and segmenting itself
 730                         wfProfileIn( 'wikidiff2_do_diff' );
 731                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 732                         $text .= $this->debug( 'wikidiff2' );
 733                         wfProfileOut( 'wikidiff2_do_diff' );
 734                         wfProfileOut( __METHOD__ );
 735                         return $text;
 736                 }
 737                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 738                         # Diff via the shell
 739                         global $wgTmpDirectory;
 740                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 741                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 742
 743                         $tempFile1 = fopen( $tempName1, "w" );
 744                         if ( !$tempFile1 ) {
 745                                 wfProfileOut( __METHOD__ );
 746                                 return false;
 747                         }
 748                         $tempFile2 = fopen( $tempName2, "w" );
 749                         if ( !$tempFile2 ) {
 750                                 wfProfileOut( __METHOD__ );
 751                                 return false;
 752                         }
 753                         fwrite( $tempFile1, $otext );
 754                         fwrite( $tempFile2, $ntext );
 755                         fclose( $tempFile1 );
 756                         fclose( $tempFile2 );
 757                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 758                         wfProfileIn( __METHOD__ . "-shellexec" );
 759                         $difftext = wfShellExec( $cmd );
 760                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 761                         wfProfileOut( __METHOD__ . "-shellexec" );
 762                         unlink( $tempName1 );
 763                         unlink( $tempName2 );
 764                         wfProfileOut( __METHOD__ );
 765                         return $difftext;
 766                 }
 767
 768                 # Native PHP diff
 769                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 770                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 771                 $diffs = new Diff( $ota, $nta );
 772                 $formatter = new TableDiffFormatter();
 773                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 774                 wfProfileOut( __METHOD__ );
 775                 return $difftext;
 776         }
 777
 778         /**
 779          * Generate a debug comment indicating diff generating time,
 780          * server node, and generator backend.
 781          */
 782         protected function debug( $generator = "internal" ) {
 783                 global $wgShowHostnames;
 784                 if ( !$this->enableDebugComment ) {
 785                         return '';
 786                 }
 787                 $data = array( $generator );
 788                 if ( $wgShowHostnames ) {
 789                         $data[] = wfHostname();
 790                 }
 791                 $data[] = wfTimestamp( TS_DB );
 792                 return "<!-- diff generator: " .
 793                 implode( " ",
 794                 array_map(
 795                                         "htmlspecialchars",
 796                 $data ) ) .
 797                         " -->\n";
 798         }
 799
 800         /**
 801          * Replace line numbers with the text in the user's language
 802          */
 803         function localiseLineNumbers( $text ) {
 804                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 805                 array( &$this, 'localiseLineNumbersCb' ), $text );
 806         }
 807
 808         function localiseLineNumbersCb( $matches ) {
 809                 global $wgLang;
 810                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 811                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 812         }
 813
 814
 815         /**
 816          * If there are revisions between the ones being compared, return a note saying so.
 817          * @return string
 818          */
 819         function getMultiNotice() {
 820                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 821                         return '';
 822                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 823                         // Comparing two different pages? Count would be meaningless.
 824                         return '';
 825                 }
 826
 827                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 828                         $oldRev = $this->mNewRev; // flip
 829                         $newRev = $this->mOldRev; // flip
 830                 } else { // normal case
 831                         $oldRev = $this->mOldRev;
 832                         $newRev = $this->mNewRev;
 833                 }
 834
 835                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 836                 if ( $nEdits > 0 ) {
 837                         $limit = 100; // use diff-multi-manyusers if too many users
 838                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 839                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 840                 }
 841                 return ''; // nothing
 842         }
 843
 844         /**
 845          * Get a notice about how many intermediate edits and users there are
 846          * @param $numEdits int
 847          * @param $numUsers int
 848          * @param $limit int
 849          * @return string
 850          */
 851         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 852                 global $wgLang;
 853                 if ( $numUsers > $limit ) {
 854                         $msg = 'diff-multi-manyusers';
 855                         $numUsers = $limit;
 856                 } else {
 857                         $msg = 'diff-multi';
 858                 }
 859                 return wfMsgExt( $msg, 'parseinline',
 860                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 861         }
 862
 863         /**
 864          * Get a header for a specified revision.
 865          *
 866          * @param $rev Revision
 867          * @param $complete String: 'complete' to get the header wrapped depending
 868          *        the visibility of the revision and a link to edit the page.
 869          * @return String HTML fragment
 870          */
 871         private function getRevisionHeader( Revision $rev, $complete = '' ) {
 872                 global $wgLang;
 873
 874                 $revtimestamp = $rev->getTimestamp();
 875                 $timestamp = $wgLang->timeanddate( $revtimestamp, true );
 876                 $dateofrev = $wgLang->date( $revtimestamp, true );
 877                 $timeofrev = $wgLang->time( $revtimestamp, true );
 878
 879                 $header = htmlspecialchars( wfMsg(
 880                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 881                         $timestamp,
 882                         $dateofrev,
 883                         $timeofrev
 884                 ) );
 885
 886                 if ( $complete !== 'complete' ) {
 887                         return $header;
 888                 }
 889
 890                 $title = $rev->getTitle();
 891
 892                 $header = Linker::linkKnown( $title, $header, array(),
 893                         array( 'oldid' => $rev->getID() ) );
 894
 895                 if ( $rev->userCan( Revision::DELETED_TEXT ) ) {
 896                         $editQuery = array( 'action' => 'edit' );
 897                         if ( !$rev->isCurrent() ) {
 898                                 $editQuery['oldid'] = $rev->getID();
 899                         }
 900
 901                         $msg = wfMsgHtml( $title->userCan( 'edit' ) ? 'editold' : 'viewsourceold' );
 902                         $header .= ' (' . Linker::linkKnown( $title, $msg, array(), $editQuery ) . ')';
 903                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 904                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 905                         }
 906                 } else {
 907                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 908                 }
 909
 910                 return $header;
 911         }
 912
 913         /**
 914          * Add the header to a diff body
 915          *
 916          * @return string
 917          */
 918         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 919                 // shared.css sets diff in interface language/dir, but the actual content
 920                 // is often in a different language, mostly the page content language/dir
 921                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 922                 $header = "<table class='$tableClass'>";
 923
 924                 if ( !$diff && !$otitle ) {
 925                         $header .= "
 926                         <tr valign='top'>
 927                         <td class='diff-ntitle'>{$ntitle}</td>
 928                         </tr>";
 929                         $multiColspan = 1;
 930                 } else {
 931                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 932                                 $header .= "
 933                                 <col class='diff-marker' />
 934                                 <col class='diff-content' />
 935                                 <col class='diff-marker' />
 936                                 <col class='diff-content' />";
 937                                 $colspan = 2;
 938                                 $multiColspan = 4;
 939                         } else {
 940                                 $colspan = 1;
 941                                 $multiColspan = 2;
 942                         }
 943                         $header .= "
 944                         <tr valign='top'>
 945                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 946                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 947                         </tr>";
 948                 }
 949
 950                 if ( $multi != '' ) {
 951                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 952                 }
 953                 if ( $notice != '' ) {
 954                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 955                 }
 956
 957                 return $header . $diff . "</table>";
 958         }
 959
 960         /**
 961          * Use specified text instead of loading from the database
 962          */
 963         function setText( $oldText, $newText ) {
 964                 $this->mOldtext = $oldText;
 965                 $this->mNewtext = $newText;
 966                 $this->mTextLoaded = 2;
 967                 $this->mRevisionsLoaded = true;
 968         }
 969
 970         /**
 971          * Set the language in which the diff text is written
 972          * (Defaults to page content language).
 973          * @since 1.19
 974          */
 975         function setTextLanguage( $lang ) {
 976                 $this->mDiffLang = wfGetLangObj( $lang );
 977         }
 978
 979         /**
 980          * Load revision IDs
 981          */
 982         private function loadRevisionIds() {
 983                 if ( $this->mRevisionsIdsLoaded ) {
 984                         return;
 985                 }
 986
 987                 $this->mRevisionsIdsLoaded = true;
 988
 989                 $old = $this->mOldid;
 990                 $new = $this->mNewid;
 991
 992                 if ( $new === 'prev' ) {
 993                         # Show diff between revision $old and the previous one.
 994                         # Get previous one from DB.
 995                         $this->mNewid = intval( $old );
 996                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
 997                 } elseif ( $new === 'next' ) {
 998                         # Show diff between revision $old and the next one.
 999                         # Get next one from DB.
1000                         $this->mOldid = intval( $old );
1001                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
1002                         if ( $this->mNewid === false ) {
1003                                 # if no result, NewId points to the newest old revision. The only newer
1004                                 # revision is cur, which is "0".
1005                                 $this->mNewid = 0;
1006                         }
1007                 } else {
1008                         $this->mOldid = intval( $old );
1009                         $this->mNewid = intval( $new );
1010                         wfRunHooks( 'NewDifferenceEngine', array( &$this->mTitle, &$this->mOldid, &$this->mNewid, $old, $new ) );
1011                 }
1012         }
1013
1014         /**
1015          * Load revision metadata for the specified articles. If newid is 0, then compare
1016          * the old article in oldid to the current article; if oldid is 0, then
1017          * compare the current article to the immediately previous one (ignoring the
1018          * value of newid).
1019          *
1020          * If oldid is false, leave the corresponding revision object set
1021          * to false. This is impossible via ordinary user input, and is provided for
1022          * API convenience.
1023          *
1024          * @return bool
1025          */
1026         function loadRevisionData() {
1027                 if ( $this->mRevisionsLoaded ) {
1028                         return true;
1029                 }
1030
1031                 // Whether it succeeds or fails, we don't want to try again
1032                 $this->mRevisionsLoaded = true;
1033
1034                 $this->loadRevisionIds();
1035
1036                 // Load the new revision object
1037                 $this->mNewRev = $this->mNewid
1038                         ? Revision::newFromId( $this->mNewid )
1039                         : Revision::newFromTitle( $this->mTitle );
1040
1041                 if ( !$this->mNewRev instanceof Revision ) {
1042                         return false;
1043                 }
1044
1045                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1046                 $this->mNewid = $this->mNewRev->getId();
1047                 $this->mNewPage = $this->mNewRev->getTitle();
1048
1049                 // Load the old revision object
1050                 $this->mOldRev = false;
1051                 if ( $this->mOldid ) {
1052                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1053                 } elseif ( $this->mOldid === 0 ) {
1054                         $rev = $this->mNewRev->getPrevious();
1055                         if ( $rev ) {
1056                                 $this->mOldid = $rev->getId();
1057                                 $this->mOldRev = $rev;
1058                         } else {
1059                                 // No previous revision; mark to show as first-version only.
1060                                 $this->mOldid = false;
1061                                 $this->mOldRev = false;
1062                         }
1063                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1064
1065                 if ( is_null( $this->mOldRev ) ) {
1066                         return false;
1067                 }
1068
1069                 if ( $this->mOldRev ) {
1070                         $this->mOldPage = $this->mOldRev->getTitle();
1071                 }
1072
1073                 return true;
1074         }
1075
1076         /**
1077          * Load the text of the revisions, as well as revision data.
1078          *
1079          * @return bool
1080          */
1081         function loadText() {
1082                 if ( $this->mTextLoaded == 2 ) {
1083                         return true;
1084                 } else {
1085                         // Whether it succeeds or fails, we don't want to try again
1086                         $this->mTextLoaded = 2;
1087                 }
1088
1089                 if ( !$this->loadRevisionData() ) {
1090                         return false;
1091                 }
1092                 if ( $this->mOldRev ) {
1093                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1094                         if ( $this->mOldtext === false ) {
1095                                 return false;
1096                         }
1097                 }
1098                 if ( $this->mNewRev ) {
1099                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1100                         if ( $this->mNewtext === false ) {
1101                                 return false;
1102                         }
1103                 }
1104                 return true;
1105         }
1106
1107         /**
1108          * Load the text of the new revision, not the old one
1109          *
1110          * @return bool
1111          */
1112         function loadNewText() {
1113                 if ( $this->mTextLoaded >= 1 ) {
1114                         return true;
1115                 } else {
1116                         $this->mTextLoaded = 1;
1117                 }
1118                 if ( !$this->loadRevisionData() ) {
1119                         return false;
1120                 }
1121                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1122                 return true;
1123         }
1124 }