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, $mTitle;
  26         var $mOldtitle, $mNewtitle, $mPagetitle;
  27         var $mOldtext, $mNewtext;
  28         var $mOldPage, $mNewPage;
  29         var $mRcidMarkPatrolled;
  30         var $mOldRev, $mNewRev;
  31         var $mRevisionsLoaded = false; // Have the revisions been loaded
  32         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  33         var $mCacheHit = false; // Was the diff fetched from cache?
  34
  35         /**
  36          * Set this to true to add debug info to the HTML output.
  37          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  38          * (bug 20601)
  39          */
  40         var $enableDebugComment = false;
  41
  42         // If true, line X is not displayed when X is 1, for example to increase
  43         // readability and conserve space with many small diffs.
  44         protected $mReducedLineNumbers = false;
  45
  46         protected $unhide = false; # show rev_deleted content if allowed
  47         /**#@-*/
  48
  49         /**
  50          * Constructor
  51          * @param $titleObj Title object that the diff is associated with
  52          * @param $old Integer: old ID we want to show and diff with.
  53          * @param $new String: either 'prev' or 'next'.
  54          * @param $rcid Integer: ??? FIXME (default 0)
  55          * @param $refreshCache boolean If set, refreshes the diff cache
  56          * @param $unhide boolean If set, allow viewing deleted revs
  57          */
  58         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  59                 $refreshCache = false, $unhide = false )
  60         {
  61                 if ( $titleObj ) {
  62                         $this->mTitle = $titleObj;
  63                 } else {
  64                         global $wgTitle;
  65                         $this->mTitle = $wgTitle;
  66                 }
  67                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  68
  69                 if ( 'prev' === $new ) {
  70                         # Show diff between revision $old and the previous one.
  71                         # Get previous one from DB.
  72                         $this->mNewid = intval( $old );
  73                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  74                 } elseif ( 'next' === $new ) {
  75                         # Show diff between revision $old and the next one.
  76                         # Get next one from DB.
  77                         $this->mOldid = intval( $old );
  78                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  79                         if ( false === $this->mNewid ) {
  80                                 # if no result, NewId points to the newest old revision. The only newer
  81                                 # revision is cur, which is "0".
  82                                 $this->mNewid = 0;
  83                         }
  84                 } else {
  85                         $this->mOldid = intval( $old );
  86                         $this->mNewid = intval( $new );
  87                         wfRunHooks( 'NewDifferenceEngine', array( &$titleObj, &$this->mOldid, &$this->mNewid, $old, $new ) );
  88                 }
  89                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  90                 $this->mRefreshCache = $refreshCache;
  91                 $this->unhide = $unhide;
  92         }
  93
  94         function setReducedLineNumbers( $value = true ) {
  95                 $this->mReducedLineNumbers = $value;
  96         }
  97
  98         function getTitle() {
  99                 return $this->mTitle;
 100         }
 101
 102         function wasCacheHit() {
 103                 return $this->mCacheHit;
 104         }
 105
 106         function getOldid() {
 107                 return $this->mOldid;
 108         }
 109
 110         function getNewid() {
 111                 return $this->mNewid;
 112         }
 113
 114         function showDiffPage( $diffOnly = false ) {
 115                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol;
 116                 wfProfileIn( __METHOD__ );
 117
 118
 119                 # If external diffs are enabled both globally and for the user,
 120                 # we'll use the application/x-external-editor interface to call
 121                 # an external diff tool like kompare, kdiff3, etc.
 122                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 123                         global $wgInputEncoding, $wgServer, $wgScript, $wgLang;
 124                         $wgOut->disable();
 125                         header ( "Content-type: application/x-external-editor; charset=" . $wgInputEncoding );
 126                         $url1 = $this->mTitle->getFullURL( array(
 127                                 'action' => 'raw',
 128                                 'oldid' => $this->mOldid
 129                         ) );
 130                         $url2 = $this->mTitle->getFullURL( array(
 131                                 'action' => 'raw',
 132                                 'oldid' => $this->mNewid
 133                         ) );
 134                         $special = $wgLang->getNsText( NS_SPECIAL );
 135                         $control = <<<CONTROL
 136                         [Process]
 137                         Type=Diff text
 138                         Engine=MediaWiki
 139                         Script={$wgServer}{$wgScript}
 140                         Special namespace={$special}
 141
 142                         [File]
 143                         Extension=wiki
 144                         URL=$url1
 145
 146                         [File 2]
 147                         Extension=wiki
 148                         URL=$url2
 149 CONTROL;
 150                         echo( $control );
 151                         return;
 152                 }
 153
 154                 $wgOut->setArticleFlag( false );
 155                 if ( !$this->loadRevisionData() ) {
 156                         $t = $this->mTitle->getPrefixedText();
 157                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 158                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 159                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 160                         wfProfileOut( __METHOD__ );
 161                         return;
 162                 }
 163
 164                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 165
 166                 if ( $this->mNewRev->isCurrent() ) {
 167                         $wgOut->setArticleFlag( true );
 168                 }
 169
 170                 # mOldid is false if the difference engine is called with a "vague" query for
 171                 # a diff between a version V and its previous version V' AND the version V
 172                 # is the first version of that article. In that case, V' does not exist.
 173                 if ( $this->mOldid === false ) {
 174                         $this->showFirstRevision();
 175                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 176                         wfProfileOut( __METHOD__ );
 177                         return;
 178                 }
 179
 180                 $wgOut->suppressQuickbar();
 181
 182                 $oldTitle = $this->mOldPage->getPrefixedText();
 183                 $newTitle = $this->mNewPage->getPrefixedText();
 184                 if ( $oldTitle == $newTitle ) {
 185                         $wgOut->setPageTitle( $newTitle );
 186                 } else {
 187                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 188                 }
 189                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 190                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 191                 } else {
 192                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 193                 }
 194                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 195
 196                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 197                         $wgOut->loginToUse();
 198                         $wgOut->output();
 199                         $wgOut->disable();
 200                         wfProfileOut( __METHOD__ );
 201                         return;
 202                 }
 203
 204                 $sk = $wgUser->getSkin();
 205
 206                 // Check if page is editable
 207                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 208                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 209                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 210                 } else {
 211                         $rollback = '';
 212                 }
 213
 214                 // Prepare a change patrol link, if applicable
 215                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 216                         // If we've been given an explicit change identifier, use it; saves time
 217                         if ( $this->mRcidMarkPatrolled ) {
 218                                 $rcid = $this->mRcidMarkPatrolled;
 219                                 $rc = RecentChange::newFromId( $rcid );
 220                                 // Already patrolled?
 221                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 222                         } else {
 223                                 // Look for an unpatrolled change corresponding to this diff
 224                                 $db = wfGetDB( DB_SLAVE );
 225                                 $change = RecentChange::newFromConds(
 226                                         array(
 227                                         // Redundant user,timestamp condition so we can use the existing index
 228                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 229                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 230                                                 'rc_this_oldid' => $this->mNewid,
 231                                                 'rc_last_oldid' => $this->mOldid,
 232                                                 'rc_patrolled'  => 0
 233                                         ),
 234                                         __METHOD__
 235                                 );
 236                                 if ( $change instanceof RecentChange ) {
 237                                         $rcid = $change->mAttribs['rc_id'];
 238                                         $this->mRcidMarkPatrolled = $rcid;
 239                                 } else {
 240                                         // None found
 241                                         $rcid = 0;
 242                                 }
 243                         }
 244                         // Build the link
 245                         if ( $rcid ) {
 246                                 $token = $wgUser->editToken( $rcid );
 247                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 248                                         $this->mTitle,
 249                                         wfMsgHtml( 'markaspatrolleddiff' ),
 250                                         array(),
 251                                         array(
 252                                                 'action' => 'markpatrolled',
 253                                                 'rcid' => $rcid,
 254                                                 'token' => $token,
 255                                         ),
 256                                         array(
 257                                                 'known',
 258                                                 'noclasses'
 259                                         )
 260                                 ) . ']</span>';
 261                         } else {
 262                                 $patrol = '';
 263                         }
 264                 } else {
 265                         $patrol = '';
 266                 }
 267
 268                 # Carry over 'diffonly' param via navigation links
 269                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 270                         $query['diffonly'] = $diffOnly;
 271                 }
 272
 273                 # Make "previous revision link"
 274                 $query['diff'] = 'prev';
 275                 $query['oldid'] = $this->mOldid;
 276                 # Cascade unhide param in links for easy deletion browsing
 277                 if ( $this->unhide ) {
 278                         $query['unhide'] = 1;
 279                 }
 280                 if ( !$this->mOldRev->getPrevious() ) {
 281                         $prevlink = '&#160;';
 282                 } else {
 283                         $prevlink = $sk->link(
 284                                 $this->mTitle,
 285                                 wfMsgHtml( 'previousdiff' ),
 286                                 array(
 287                                         'id' => 'differences-prevlink'
 288                                 ),
 289                                 $query,
 290                                 array(
 291                                         'known',
 292                                         'noclasses'
 293                                 )
 294                         );
 295                 }
 296
 297                 # Make "next revision link"
 298                 $query['diff'] = 'next';
 299                 $query['oldid'] = $this->mNewid;
 300                 # Skip next link on the top revision
 301                 if ( $this->mNewRev->isCurrent() ) {
 302                         $nextlink = '&#160;';
 303                 } else {
 304                         $nextlink = $sk->link(
 305                                 $this->mTitle,
 306                                 wfMsgHtml( 'nextdiff' ),
 307                                 array(
 308                                         'id' => 'differences-nextlink'
 309                                 ),
 310                                 $query,
 311                                 array(
 312                                         'known',
 313                                         'noclasses'
 314                                 )
 315                         );
 316                 }
 317
 318                 $oldminor = '';
 319                 $newminor = '';
 320
 321                 if ( $this->mOldRev->isMinor() ) {
 322                         $oldminor = ChangesList::flag( 'minor' );
 323                 }
 324                 if ( $this->mNewRev->isMinor() ) {
 325                         $newminor = ChangesList::flag( 'minor' );
 326                 }
 327
 328                 # Handle RevisionDelete links...
 329                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 330                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 331
 332                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 333                         '<div id="mw-diff-otitle2">' .
 334                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 335                         '<div id="mw-diff-otitle3">' . $oldminor .
 336                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 337                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 338                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 339                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 340                                 " $rollback</div>" .
 341                         '<div id="mw-diff-ntitle3">' . $newminor .
 342                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 343                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 344
 345                 # Check if this user can see the revisions
 346                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 347                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 348                 # Check if one of the revisions is deleted/suppressed
 349                 $deleted = $suppressed = false;
 350                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 351                         $deleted = true; // old revisions text is hidden
 352                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 353                                 $suppressed = true; // also suppressed
 354                 }
 355                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 356                         $deleted = true; // new revisions text is hidden
 357                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 358                                 $suppressed = true; // also suppressed
 359                 }
 360                 # If the diff cannot be shown due to a deleted revision, then output
 361                 # the diff header and links to unhide (if available)...
 362                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 363                         $this->showDiffStyle();
 364                         $multi = $this->getMultiNotice();
 365                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 366                         if ( !$allowed ) {
 367                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 368                                 # Give explanation for why revision is not visible
 369                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
 370                                         array( $msg ) );
 371                         } else {
 372                                 # Give explanation and add a link to view the diff...
 373                                 $link = $this->mTitle->getFullUrl( array(
 374                                         'diff' => $this->mNewid,
 375                                         'oldid' => $this->mOldid,
 376                                         'unhide' => 1
 377                                 ) );
 378                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 379                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 380                         }
 381                 # Otherwise, output a regular diff...
 382                 } else {
 383                         # Add deletion notice if the user is viewing deleted content
 384                         $notice = '';
 385                         if ( $deleted ) {
 386                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 387                                 $notice = "<div class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 388                         }
 389                         $this->showDiff( $oldHeader, $newHeader, $notice );
 390                         if ( !$diffOnly ) {
 391                                 $this->renderNewRevision();
 392                         }
 393                 }
 394                 wfProfileOut( __METHOD__ );
 395         }
 396
 397         protected function revisionDeleteLink( $rev ) {
 398                 global $wgUser;
 399                 $link = '';
 400                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 401                 // Show del/undel link if:
 402                 // (a) the user can delete revisions, or
 403                 // (b) the user can view deleted revision *and* this one is deleted
 404                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 405                         $sk = $wgUser->getSkin();
 406                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 407                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 408                         } else {
 409                                 $query = array(
 410                                         'type'   => 'revision',
 411                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 412                                         'ids'    => $rev->getId()
 413                                 );
 414                                 $link = $sk->revDeleteLink( $query,
 415                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 416                         }
 417                         $link = '&#160;&#160;&#160;' . $link . ' ';
 418                 }
 419                 return $link;
 420         }
 421
 422         /**
 423          * Show the new revision of the page.
 424          */
 425         function renderNewRevision() {
 426                 global $wgOut, $wgUser;
 427                 wfProfileIn( __METHOD__ );
 428
 429                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 430                 if ( !wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 431                         return;
 432                 }
 433
 434                 # Add deleted rev tag if needed
 435                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 436                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", 'rev-deleted-text-permission' );
 437                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 438                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", 'rev-deleted-text-view' );
 439                 }
 440
 441                 $pCache = true;
 442                 if ( !$this->mNewRev->isCurrent() ) {
 443                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 444                         $pCache = false;
 445                 }
 446
 447                 $this->loadNewText();
 448                 if ( is_object( $this->mNewRev ) ) {
 449                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 450                 }
 451
 452                 if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 453                         // Stolen from Article::view --AG 2007-10-11
 454                         // Give hooks a chance to customise the output
 455                         if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 456                                 // Wrap the whole lot in a <pre> and don't parse
 457                                 $m = array();
 458                                 preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 459                                 $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 460                                 $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 461                                 $wgOut->addHTML( "\n</pre>\n" );
 462                         }
 463                 } elseif ( $pCache ) {
 464                         $article = new Article( $this->mTitle, 0 );
 465                         $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 466                         if( $pOutput ) {
 467                                 $wgOut->addParserOutput( $pOutput );
 468                         } else {
 469                                 $article->doViewParse();
 470                         }
 471                 } else {
 472                         $wgOut->addWikiTextTidy( $this->mNewtext );
 473                 }
 474
 475                 if ( is_object( $this->mNewRev ) && !$this->mNewRev->isCurrent() ) {
 476                         $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 477                 }
 478
 479                 # Add redundant patrol link on bottom...
 480                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 481                         $sk = $wgUser->getSkin();
 482                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 483                         $wgOut->addHTML(
 484                                 "<div class='patrollink'>[" . $sk->link(
 485                                         $this->mTitle,
 486                                         wfMsgHtml( 'markaspatrolleddiff' ),
 487                                         array(),
 488                                         array(
 489                                                 'action' => 'markpatrolled',
 490                                                 'rcid' => $this->mRcidMarkPatrolled,
 491                                                 'token' => $token,
 492                                         )
 493                                 ) . ']</div>'
 494                          );
 495                 }
 496
 497                 wfProfileOut( __METHOD__ );
 498         }
 499
 500         /**
 501          * Show the first revision of an article. Uses normal diff headers in
 502          * contrast to normal "old revision" display style.
 503          */
 504         function showFirstRevision() {
 505                 global $wgOut, $wgUser;
 506                 wfProfileIn( __METHOD__ );
 507
 508                 # Get article text from the DB
 509                 #
 510                 if ( ! $this->loadNewText() ) {
 511                         $t = $this->mTitle->getPrefixedText();
 512                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 513                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 514                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 515                         wfProfileOut( __METHOD__ );
 516                         return;
 517                 }
 518                 if ( $this->mNewRev->isCurrent() ) {
 519                         $wgOut->setArticleFlag( true );
 520                 }
 521
 522                 # Check if user is allowed to look at this page. If not, bail out.
 523                 #
 524                 if ( !$this->mTitle->userCanRead() ) {
 525                         $wgOut->loginToUse();
 526                         $wgOut->output();
 527                         wfProfileOut( __METHOD__ );
 528                         throw new MWException( "Permission Error: you do not have access to view this page" );
 529                 }
 530
 531                 # Prepare the header box
 532                 #
 533                 $sk = $wgUser->getSkin();
 534
 535                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 536                 if ( !$next ) {
 537                         $nextlink = '';
 538                 } else {
 539                         $nextlink = '<br />' . $sk->link(
 540                                 $this->mTitle,
 541                                 wfMsgHtml( 'nextdiff' ),
 542                                 array(
 543                                         'id' => 'differences-nextlink'
 544                                 ),
 545                                 array(
 546                                         'diff' => 'next',
 547                                         'oldid' => $this->mNewid,
 548                                 ),
 549                                 array(
 550                                         'known',
 551                                         'noclasses'
 552                                 )
 553                         );
 554                 }
 555                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 556                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 557
 558                 $wgOut->addHTML( $header );
 559
 560                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 561                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 562
 563                 wfProfileOut( __METHOD__ );
 564         }
 565
 566         /**
 567          * Get the diff text, send it to $wgOut
 568          * Returns false if the diff could not be generated, otherwise returns true
 569          */
 570         function showDiff( $otitle, $ntitle, $notice = '' ) {
 571                 global $wgOut;
 572                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 573                 if ( $diff === false ) {
 574                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 575                         return false;
 576                 } else {
 577                         $this->showDiffStyle();
 578                         $wgOut->addHTML( $diff );
 579                         return true;
 580                 }
 581         }
 582
 583         /**
 584          * Add style sheets and supporting JS for diff display.
 585          */
 586         function showDiffStyle() {
 587                 global $wgOut;
 588                 $wgOut->addModules( 'mediawiki.legacy.diff' );
 589         }
 590
 591         /**
 592          * Get complete diff table, including header
 593          *
 594          * @param $otitle Title: old title
 595          * @param $ntitle Title: new title
 596          * @param $notice String: HTML between diff header and body
 597          * @return mixed
 598          */
 599         function getDiff( $otitle, $ntitle, $notice = '' ) {
 600                 $body = $this->getDiffBody();
 601                 if ( $body === false ) {
 602                         return false;
 603                 } else {
 604                         $multi = $this->getMultiNotice();
 605                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 606                 }
 607         }
 608
 609         /**
 610          * Get the diff table body, without header
 611          *
 612          * @return mixed (string/false)
 613          */
 614         public function getDiffBody() {
 615                 global $wgMemc;
 616                 wfProfileIn( __METHOD__ );
 617                 $this->mCacheHit = true;
 618                 // Check if the diff should be hidden from this user
 619                 if ( !$this->loadRevisionData() ) {
 620                         return false;
 621                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 622                         return false;
 623                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 624                         return false;
 625                 }
 626                 // Short-circuit
 627                 if ( $this->mOldRev && $this->mNewRev
 628                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 629                 {
 630                         return '';
 631                 }
 632                 // Cacheable?
 633                 $key = false;
 634                 if ( $this->mOldid && $this->mNewid ) {
 635                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 636                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 637                         // Try cache
 638                         if ( !$this->mRefreshCache ) {
 639                                 $difftext = $wgMemc->get( $key );
 640                                 if ( $difftext ) {
 641                                         wfIncrStats( 'diff_cache_hit' );
 642                                         $difftext = $this->localiseLineNumbers( $difftext );
 643                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 644                                         wfProfileOut( __METHOD__ );
 645                                         return $difftext;
 646                                 }
 647                         } // don't try to load but save the result
 648                 }
 649                 $this->mCacheHit = false;
 650
 651                 // Loadtext is permission safe, this just clears out the diff
 652                 if ( !$this->loadText() ) {
 653                         wfProfileOut( __METHOD__ );
 654                         return false;
 655                 }
 656
 657                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 658
 659                 // Save to cache for 7 days
 660                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 661                         wfIncrStats( 'diff_uncacheable' );
 662                 } elseif ( $key !== false && $difftext !== false ) {
 663                         wfIncrStats( 'diff_cache_miss' );
 664                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 665                 } else {
 666                         wfIncrStats( 'diff_uncacheable' );
 667                 }
 668                 // Replace line numbers with the text in the user's language
 669                 if ( $difftext !== false ) {
 670                         $difftext = $this->localiseLineNumbers( $difftext );
 671                 }
 672                 wfProfileOut( __METHOD__ );
 673                 return $difftext;
 674         }
 675
 676         /**
 677          * Make sure the proper modules are loaded before we try to
 678          * make the diff
 679          */
 680         private function initDiffEngines() {
 681                 global $wgExternalDiffEngine;
 682                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 683                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 684                         wfSuppressWarnings();
 685                         dl( 'php_wikidiff.so' );
 686                         wfRestoreWarnings();
 687                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 688                 }
 689                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 690                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 691                         wfSuppressWarnings();
 692                         wfDl( 'wikidiff2' );
 693                         wfRestoreWarnings();
 694                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 695                 }
 696         }
 697
 698         /**
 699          * Generate a diff, no caching
 700          *
 701          * @param $otext String: old text, must be already segmented
 702          * @param $ntext String: new text, must be already segmented
 703          */
 704         function generateDiffBody( $otext, $ntext ) {
 705                 global $wgExternalDiffEngine, $wgContLang;
 706
 707                 $otext = str_replace( "\r\n", "\n", $otext );
 708                 $ntext = str_replace( "\r\n", "\n", $ntext );
 709
 710                 $this->initDiffEngines();
 711
 712                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 713                         # For historical reasons, external diff engine expects
 714                         # input text to be HTML-escaped already
 715                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 716                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 717                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 718                         $this->debug( 'wikidiff1' );
 719                 }
 720
 721                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 722                         # Better external diff engine, the 2 may some day be dropped
 723                         # This one does the escaping and segmenting itself
 724                         wfProfileIn( 'wikidiff2_do_diff' );
 725                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 726                         $text .= $this->debug( 'wikidiff2' );
 727                         wfProfileOut( 'wikidiff2_do_diff' );
 728                         return $text;
 729                 }
 730                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 731                         # Diff via the shell
 732                         global $wgTmpDirectory;
 733                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 734                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 735
 736                         $tempFile1 = fopen( $tempName1, "w" );
 737                         if ( !$tempFile1 ) {
 738                                 wfProfileOut( __METHOD__ );
 739                                 return false;
 740                         }
 741                         $tempFile2 = fopen( $tempName2, "w" );
 742                         if ( !$tempFile2 ) {
 743                                 wfProfileOut( __METHOD__ );
 744                                 return false;
 745                         }
 746                         fwrite( $tempFile1, $otext );
 747                         fwrite( $tempFile2, $ntext );
 748                         fclose( $tempFile1 );
 749                         fclose( $tempFile2 );
 750                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 751                         wfProfileIn( __METHOD__ . "-shellexec" );
 752                         $difftext = wfShellExec( $cmd );
 753                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 754                         wfProfileOut( __METHOD__ . "-shellexec" );
 755                         unlink( $tempName1 );
 756                         unlink( $tempName2 );
 757                         return $difftext;
 758                 }
 759
 760                 # Native PHP diff
 761                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 762                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 763                 $diffs = new Diff( $ota, $nta );
 764                 $formatter = new TableDiffFormatter();
 765                 return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 766                 $this->debug();
 767         }
 768
 769         /**
 770          * Generate a debug comment indicating diff generating time,
 771          * server node, and generator backend.
 772          */
 773         protected function debug( $generator = "internal" ) {
 774                 global $wgShowHostnames;
 775                 if ( !$this->enableDebugComment ) {
 776                         return '';
 777                 }
 778                 $data = array( $generator );
 779                 if ( $wgShowHostnames ) {
 780                         $data[] = wfHostname();
 781                 }
 782                 $data[] = wfTimestamp( TS_DB );
 783                 return "<!-- diff generator: " .
 784                 implode( " ",
 785                 array_map(
 786                                         "htmlspecialchars",
 787                 $data ) ) .
 788                         " -->\n";
 789         }
 790
 791         /**
 792          * Replace line numbers with the text in the user's language
 793          */
 794         function localiseLineNumbers( $text ) {
 795                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 796                 array( &$this, 'localiseLineNumbersCb' ), $text );
 797         }
 798
 799         function localiseLineNumbersCb( $matches ) {
 800                 global $wgLang;
 801                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 802                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 803         }
 804
 805
 806         /**
 807          * If there are revisions between the ones being compared, return a note saying so.
 808          * @return string
 809          */
 810         function getMultiNotice() {
 811                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 812                         return '';
 813                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 814                         // Comparing two different pages? Count would be meaningless.
 815                         return '';
 816                 }
 817
 818                 $oldid = $this->mOldRev->getId();
 819                 $newid = $this->mNewRev->getId();
 820                 if ( $oldid > $newid ) {
 821                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 822                 }
 823
 824                 $nEdits = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 825                 if ( $nEdits > 0 ) {
 826                         $limit = 100;
 827                         // We use ($limit + 1) so we can detect if there are > 100 authors
 828                         // in a given revision range. In that case, diff-multi-manyusers is used.
 829                         $numUsers = $this->mTitle->countAuthorsBetween( $oldid, $newid, $limit + 1 );
 830                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 831                 }
 832                 return ''; // nothing
 833         }
 834
 835         /**
 836          * Get a notice about how many intermediate edits and users there are
 837          * @param $numEdits int
 838          * @param $numUsers int
 839          * @param $limit int
 840          * @return string
 841          */
 842         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 843                 global $wgLang;
 844                 if ( $numUsers > $limit ) {
 845                         $msg = 'diff-multi-manyusers';
 846                         $numUsers = $limit;
 847                 } else {
 848                         $msg = 'diff-multi';
 849                 }
 850                 return wfMsgExt( $msg, 'parseinline',
 851                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 852         }
 853
 854         /**
 855          * Add the header to a diff body
 856          */
 857         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 858                 $header = "<table class='diff'>";
 859                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 860                         $header .= "
 861                         <col class='diff-marker' />
 862                         <col class='diff-content' />
 863                         <col class='diff-marker' />
 864                         <col class='diff-content' />";
 865                         $colspan = 2;
 866                         $multiColspan = 4;
 867                 } else {
 868                         $colspan = 1;
 869                         $multiColspan = 2;
 870                 }
 871                 $header .= "
 872                 <tr valign='top'>
 873                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 874                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 875                 </tr>";
 876
 877                 if ( $multi != '' ) {
 878                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 879                 }
 880                 if ( $notice != '' ) {
 881                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 882                 }
 883
 884                 return $header . $diff . "</table>";
 885         }
 886
 887         /**
 888          * Use specified text instead of loading from the database
 889          */
 890         function setText( $oldText, $newText ) {
 891                 $this->mOldtext = $oldText;
 892                 $this->mNewtext = $newText;
 893                 $this->mTextLoaded = 2;
 894                 $this->mRevisionsLoaded = true;
 895         }
 896
 897         /**
 898          * Load revision metadata for the specified articles. If newid is 0, then compare
 899          * the old article in oldid to the current article; if oldid is 0, then
 900          * compare the current article to the immediately previous one (ignoring the
 901          * value of newid).
 902          *
 903          * If oldid is false, leave the corresponding revision object set
 904          * to false. This is impossible via ordinary user input, and is provided for
 905          * API convenience.
 906          */
 907         function loadRevisionData() {
 908                 global $wgLang, $wgUser;
 909                 if ( $this->mRevisionsLoaded ) {
 910                         return true;
 911                 } else {
 912                         // Whether it succeeds or fails, we don't want to try again
 913                         $this->mRevisionsLoaded = true;
 914                 }
 915
 916                 // Load the new revision object
 917                 $this->mNewRev = $this->mNewid
 918                         ? Revision::newFromId( $this->mNewid )
 919                         : Revision::newFromTitle( $this->mTitle );
 920                 if ( !$this->mNewRev instanceof Revision )
 921                         return false;
 922
 923                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 924                 $this->mNewid = $this->mNewRev->getId();
 925
 926                 // Check if page is editable
 927                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 928
 929                 // Set assorted variables
 930                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 931                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 932                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 933                 $this->mNewPage = $this->mNewRev->getTitle();
 934                 if ( $this->mNewRev->isCurrent() ) {
 935                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 936                                 'oldid' => $this->mNewid
 937                         ) );
 938                         $this->mPagetitle = htmlspecialchars( wfMsg(
 939                                 'currentrev-asof',
 940                                 $timestamp,
 941                                 $dateofrev,
 942                                 $timeofrev
 943                         ) );
 944                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 945                                 'action' => 'edit'
 946                         ) );
 947
 948                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 949                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 950                 } else {
 951                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 952                                 'oldid' => $this->mNewid
 953                         ) );
 954                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 955                                 'action' => 'edit',
 956                                 'oldid' => $this->mNewid
 957                         ) );
 958                         $this->mPagetitle = htmlspecialchars( wfMsg(
 959                                 'revisionasof',
 960                                 $timestamp,
 961                                 $dateofrev,
 962                                 $timeofrev
 963                         ) );
 964
 965                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 966                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 967                 }
 968                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 969                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 970                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 971                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 972                 }
 973
 974                 // Load the old revision object
 975                 $this->mOldRev = false;
 976                 if ( $this->mOldid ) {
 977                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 978                 } elseif ( $this->mOldid === 0 ) {
 979                         $rev = $this->mNewRev->getPrevious();
 980                         if ( $rev ) {
 981                                 $this->mOldid = $rev->getId();
 982                                 $this->mOldRev = $rev;
 983                         } else {
 984                                 // No previous revision; mark to show as first-version only.
 985                                 $this->mOldid = false;
 986                                 $this->mOldRev = false;
 987                         }
 988                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
 989
 990                 if ( is_null( $this->mOldRev ) ) {
 991                         return false;
 992                 }
 993
 994                 if ( $this->mOldRev ) {
 995                         $this->mOldPage = $this->mOldRev->getTitle();
 996
 997                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
 998                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
 999                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1000                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1001                                 'oldid' => $this->mOldid
1002                         ) );
1003                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1004                                 'action' => 'edit',
1005                                 'oldid' => $this->mOldid
1006                         ) );
1007                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1008
1009                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1010                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1011                         // Add an "undo" link
1012                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
1013                                 'action' => 'edit',
1014                                 'undoafter' => $this->mOldid,
1015                                 'undo' => $this->mNewid
1016                         ) );
1017                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
1018                         $htmlTitle = $wgUser->getSkin()->titleAttrib( 'undo' );
1019                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1020                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
1021                         }
1022
1023                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1024                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1025                         } else if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1026                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1027                         }
1028                 }
1029
1030                 return true;
1031         }
1032
1033         /**
1034          * Load the text of the revisions, as well as revision data.
1035          */
1036         function loadText() {
1037                 if ( $this->mTextLoaded == 2 ) {
1038                         return true;
1039                 } else {
1040                         // Whether it succeeds or fails, we don't want to try again
1041                         $this->mTextLoaded = 2;
1042                 }
1043
1044                 if ( !$this->loadRevisionData() ) {
1045                         return false;
1046                 }
1047                 if ( $this->mOldRev ) {
1048                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1049                         if ( $this->mOldtext === false ) {
1050                                 return false;
1051                         }
1052                 }
1053                 if ( $this->mNewRev ) {
1054                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1055                         if ( $this->mNewtext === false ) {
1056                                 return false;
1057                         }
1058                 }
1059                 return true;
1060         }
1061
1062         /**
1063          * Load the text of the new revision, not the old one
1064          */
1065         function loadNewText() {
1066                 if ( $this->mTextLoaded >= 1 ) {
1067                         return true;
1068                 } else {
1069                         $this->mTextLoaded = 1;
1070                 }
1071                 if ( !$this->loadRevisionData() ) {
1072                         return false;
1073                 }
1074                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1075                 return true;
1076         }
1077 }