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