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