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 = $wgTitle; // @TODO: get rid of this
  66                 }
  67                 wfDebug( "DifferenceEngine old '$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                 # Allow frames except in certain special cases
 119                 $wgOut->allowClickjacking();
 120
 121                 # If external diffs are enabled both globally and for the user,
 122                 # we'll use the application/x-external-editor interface to call
 123                 # an external diff tool like kompare, kdiff3, etc.
 124                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 125                         global $wgInputEncoding, $wgServer, $wgScript, $wgLang;
 126                         $wgOut->disable();
 127                         header ( "Content-type: application/x-external-editor; charset=" . $wgInputEncoding );
 128                         $url1 = $this->mTitle->getFullURL( array(
 129                                 'action' => 'raw',
 130                                 'oldid' => $this->mOldid
 131                         ) );
 132                         $url2 = $this->mTitle->getFullURL( array(
 133                                 'action' => 'raw',
 134                                 'oldid' => $this->mNewid
 135                         ) );
 136                         $special = $wgLang->getNsText( NS_SPECIAL );
 137                         $control = <<<CONTROL
 138                         [Process]
 139                         Type=Diff text
 140                         Engine=MediaWiki
 141                         Script={$wgServer}{$wgScript}
 142                         Special namespace={$special}
 143
 144                         [File]
 145                         Extension=wiki
 146                         URL=$url1
 147
 148                         [File 2]
 149                         Extension=wiki
 150                         URL=$url2
 151 CONTROL;
 152                         echo( $control );
 153
 154                         wfProfileOut( __METHOD__ );
 155                         return;
 156                 }
 157
 158                 $wgOut->setArticleFlag( false );
 159                 if ( !$this->loadRevisionData() ) {
 160                         $t = $this->mTitle->getPrefixedText();
 161                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 162                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 163                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 164                         wfProfileOut( __METHOD__ );
 165                         return;
 166                 }
 167
 168                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 169
 170                 if ( $this->mNewRev->isCurrent() ) {
 171                         $wgOut->setArticleFlag( true );
 172                 }
 173
 174                 # mOldid is false if the difference engine is called with a "vague" query for
 175                 # a diff between a version V and its previous version V' AND the version V
 176                 # is the first version of that article. In that case, V' does not exist.
 177                 if ( $this->mOldid === false ) {
 178                         $this->showFirstRevision();
 179                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 180                         wfProfileOut( __METHOD__ );
 181                         return;
 182                 }
 183
 184                 $oldTitle = $this->mOldPage->getPrefixedText();
 185                 $newTitle = $this->mNewPage->getPrefixedText();
 186                 if ( $oldTitle == $newTitle ) {
 187                         $wgOut->setPageTitle( $newTitle );
 188                 } else {
 189                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 190                 }
 191                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 192                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 193                 } else {
 194                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 195                 }
 196                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 197
 198                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 199                         $wgOut->loginToUse();
 200                         $wgOut->output();
 201                         $wgOut->disable();
 202                         wfProfileOut( __METHOD__ );
 203                         return;
 204                 }
 205
 206                 $sk = $wgUser->getSkin();
 207                 if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 208                         $sk->suppressQuickbar();
 209                 }
 210
 211                 // Check if page is editable
 212                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 213                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 214                         $wgOut->preventClickjacking();
 215                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 216                 } else {
 217                         $rollback = '';
 218                 }
 219
 220                 // Prepare a change patrol link, if applicable
 221                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 222                         // If we've been given an explicit change identifier, use it; saves time
 223                         if ( $this->mRcidMarkPatrolled ) {
 224                                 $rcid = $this->mRcidMarkPatrolled;
 225                                 $rc = RecentChange::newFromId( $rcid );
 226                                 // Already patrolled?
 227                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 228                         } else {
 229                                 // Look for an unpatrolled change corresponding to this diff
 230                                 $db = wfGetDB( DB_SLAVE );
 231                                 $change = RecentChange::newFromConds(
 232                                         array(
 233                                         // Redundant user,timestamp condition so we can use the existing index
 234                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 235                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 236                                                 'rc_this_oldid' => $this->mNewid,
 237                                                 'rc_last_oldid' => $this->mOldid,
 238                                                 'rc_patrolled'  => 0
 239                                         ),
 240                                         __METHOD__
 241                                 );
 242                                 if ( $change instanceof RecentChange ) {
 243                                         $rcid = $change->mAttribs['rc_id'];
 244                                         $this->mRcidMarkPatrolled = $rcid;
 245                                 } else {
 246                                         // None found
 247                                         $rcid = 0;
 248                                 }
 249                         }
 250                         // Build the link
 251                         if ( $rcid ) {
 252                                 $wgOut->preventClickjacking();
 253                                 $token = $wgUser->editToken( $rcid );
 254                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 255                                         $this->mTitle,
 256                                         wfMsgHtml( 'markaspatrolleddiff' ),
 257                                         array(),
 258                                         array(
 259                                                 'action' => 'markpatrolled',
 260                                                 'rcid' => $rcid,
 261                                                 'token' => $token,
 262                                         ),
 263                                         array(
 264                                                 'known',
 265                                                 'noclasses'
 266                                         )
 267                                 ) . ']</span>';
 268                         } else {
 269                                 $patrol = '';
 270                         }
 271                 } else {
 272                         $patrol = '';
 273                 }
 274
 275                 # Carry over 'diffonly' param via navigation links
 276                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 277                         $query['diffonly'] = $diffOnly;
 278                 }
 279
 280                 # Make "previous revision link"
 281                 $query['diff'] = 'prev';
 282                 $query['oldid'] = $this->mOldid;
 283                 # Cascade unhide param in links for easy deletion browsing
 284                 if ( $this->unhide ) {
 285                         $query['unhide'] = 1;
 286                 }
 287                 if ( !$this->mOldRev->getPrevious() ) {
 288                         $prevlink = '&#160;';
 289                 } else {
 290                         $prevlink = $sk->link(
 291                                 $this->mTitle,
 292                                 wfMsgHtml( 'previousdiff' ),
 293                                 array(
 294                                         'id' => 'differences-prevlink'
 295                                 ),
 296                                 $query,
 297                                 array(
 298                                         'known',
 299                                         'noclasses'
 300                                 )
 301                         );
 302                 }
 303
 304                 # Make "next revision link"
 305                 $query['diff'] = 'next';
 306                 $query['oldid'] = $this->mNewid;
 307                 # Skip next link on the top revision
 308                 if ( $this->mNewRev->isCurrent() ) {
 309                         $nextlink = '&#160;';
 310                 } else {
 311                         $nextlink = $sk->link(
 312                                 $this->mTitle,
 313                                 wfMsgHtml( 'nextdiff' ),
 314                                 array(
 315                                         'id' => 'differences-nextlink'
 316                                 ),
 317                                 $query,
 318                                 array(
 319                                         'known',
 320                                         'noclasses'
 321                                 )
 322                         );
 323                 }
 324
 325                 $oldminor = '';
 326                 $newminor = '';
 327
 328                 if ( $this->mOldRev->isMinor() ) {
 329                         $oldminor = ChangesList::flag( 'minor' );
 330                 }
 331                 if ( $this->mNewRev->isMinor() ) {
 332                         $newminor = ChangesList::flag( 'minor' );
 333                 }
 334
 335                 # Handle RevisionDelete links...
 336                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 337                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 338
 339                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 340                         '<div id="mw-diff-otitle2">' .
 341                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 342                         '<div id="mw-diff-otitle3">' . $oldminor .
 343                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 344                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 345                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 346                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 347                                 " $rollback</div>" .
 348                         '<div id="mw-diff-ntitle3">' . $newminor .
 349                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 350                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 351
 352                 # Check if this user can see the revisions
 353                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 354                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 355                 # Check if one of the revisions is deleted/suppressed
 356                 $deleted = $suppressed = false;
 357                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 358                         $deleted = true; // old revisions text is hidden
 359                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 360                                 $suppressed = true; // also suppressed
 361                 }
 362                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 363                         $deleted = true; // new revisions text is hidden
 364                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 365                                 $suppressed = true; // also suppressed
 366                 }
 367                 # If the diff cannot be shown due to a deleted revision, then output
 368                 # the diff header and links to unhide (if available)...
 369                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 370                         $this->showDiffStyle();
 371                         $multi = $this->getMultiNotice();
 372                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 373                         if ( !$allowed ) {
 374                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 375                                 # Give explanation for why revision is not visible
 376                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 377                                         array( $msg ) );
 378                         } else {
 379                                 # Give explanation and add a link to view the diff...
 380                                 $link = $this->mTitle->getFullUrl( array(
 381                                         'diff' => $this->mNewid,
 382                                         'oldid' => $this->mOldid,
 383                                         'unhide' => 1
 384                                 ) );
 385                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 386                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 387                         }
 388                 # Otherwise, output a regular diff...
 389                 } else {
 390                         # Add deletion notice if the user is viewing deleted content
 391                         $notice = '';
 392                         if ( $deleted ) {
 393                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 394                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 395                         }
 396                         $this->showDiff( $oldHeader, $newHeader, $notice );
 397                         if ( !$diffOnly ) {
 398                                 $this->renderNewRevision();
 399                         }
 400                 }
 401                 wfProfileOut( __METHOD__ );
 402         }
 403
 404         protected function revisionDeleteLink( $rev ) {
 405                 global $wgUser;
 406                 $link = '';
 407                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 408                 // Show del/undel link if:
 409                 // (a) the user can delete revisions, or
 410                 // (b) the user can view deleted revision *and* this one is deleted
 411                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 412                         $sk = $wgUser->getSkin();
 413                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 414                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 415                         } else {
 416                                 $query = array(
 417                                         'type'   => 'revision',
 418                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 419                                         'ids'    => $rev->getId()
 420                                 );
 421                                 $link = $sk->revDeleteLink( $query,
 422                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 423                         }
 424                         $link = '&#160;&#160;&#160;' . $link . ' ';
 425                 }
 426                 return $link;
 427         }
 428
 429         /**
 430          * Show the new revision of the page.
 431          */
 432         function renderNewRevision() {
 433                 global $wgOut, $wgUser;
 434                 wfProfileIn( __METHOD__ );
 435                 # Add "current version as of X" title
 436                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 437                 # Page content may be handled by a hooked call instead...
 438                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 439                         # Use the current version parser cache if applicable
 440                         $pCache = true;
 441                         if ( !$this->mNewRev->isCurrent() ) {
 442                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 443                                 $pCache = false;
 444                         }
 445
 446                         $this->loadNewText();
 447                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 448
 449                         if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 450                                 // Stolen from Article::view --AG 2007-10-11
 451                                 // Give hooks a chance to customise the output
 452                                 // @TODO: standardize this crap into one function
 453                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 454                                         // Wrap the whole lot in a <pre> and don't parse
 455                                         $m = array();
 456                                         preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 457                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 458                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 459                                         $wgOut->addHTML( "\n</pre>\n" );
 460                                 }
 461                         } elseif ( $pCache ) {
 462                                 $article = new Article( $this->mTitle, 0 );
 463                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 464                                 if( $pOutput ) {
 465                                         $wgOut->addParserOutput( $pOutput );
 466                                 } else {
 467                                         $article->doViewParse();
 468                                 }
 469                         } else {
 470                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 471                         }
 472
 473                         if ( !$this->mNewRev->isCurrent() ) {
 474                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 475                         }
 476                 }
 477                 # Add redundant patrol link on bottom...
 478                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 479                         $sk = $wgUser->getSkin();
 480                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 481                         $wgOut->preventClickjacking();
 482                         $wgOut->addHTML(
 483                                 "<div class='patrollink'>[" . $sk->link(
 484                                         $this->mTitle,
 485                                         wfMsgHtml( 'markaspatrolleddiff' ),
 486                                         array(),
 487                                         array(
 488                                                 'action'        => 'markpatrolled',
 489                                                 'rcid'          => $this->mRcidMarkPatrolled,
 490                                                 'token'         => $token,
 491                                         )
 492                                 ) . ']</div>'
 493                          );
 494                 }
 495
 496                 wfProfileOut( __METHOD__ );
 497         }
 498
 499         /**
 500          * Show the first revision of an article. Uses normal diff headers in
 501          * contrast to normal "old revision" display style.
 502          */
 503         function showFirstRevision() {
 504                 global $wgOut, $wgUser;
 505                 wfProfileIn( __METHOD__ );
 506
 507                 # Get article text from the DB
 508                 #
 509                 if ( ! $this->loadNewText() ) {
 510                         $t = $this->mTitle->getPrefixedText();
 511                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 512                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 513                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 514                         wfProfileOut( __METHOD__ );
 515                         return;
 516                 }
 517                 if ( $this->mNewRev->isCurrent() ) {
 518                         $wgOut->setArticleFlag( true );
 519                 }
 520
 521                 # Check if user is allowed to look at this page. If not, bail out.
 522                 #
 523                 if ( !$this->mTitle->userCanRead() ) {
 524                         $wgOut->loginToUse();
 525                         $wgOut->output();
 526                         wfProfileOut( __METHOD__ );
 527                         throw new MWException( "Permission Error: you do not have access to view this page" );
 528                 }
 529
 530                 # Prepare the header box
 531                 #
 532                 $sk = $wgUser->getSkin();
 533
 534                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 535                 if ( !$next ) {
 536                         $nextlink = '';
 537                 } else {
 538                         $nextlink = '<br />' . $sk->link(
 539                                 $this->mTitle,
 540                                 wfMsgHtml( 'nextdiff' ),
 541                                 array(
 542                                         'id' => 'differences-nextlink'
 543                                 ),
 544                                 array(
 545                                         'diff' => 'next',
 546                                         'oldid' => $this->mNewid,
 547                                 ),
 548                                 array(
 549                                         'known',
 550                                         'noclasses'
 551                                 )
 552                         );
 553                 }
 554                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 555                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 556
 557                 $wgOut->addHTML( $header );
 558
 559                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 560                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 561
 562                 wfProfileOut( __METHOD__ );
 563         }
 564
 565         /**
 566          * Get the diff text, send it to $wgOut
 567          * Returns false if the diff could not be generated, otherwise returns true
 568          */
 569         function showDiff( $otitle, $ntitle, $notice = '' ) {
 570                 global $wgOut;
 571                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 572                 if ( $diff === false ) {
 573                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 574                         return false;
 575                 } else {
 576                         $this->showDiffStyle();
 577                         $wgOut->addHTML( $diff );
 578                         return true;
 579                 }
 580         }
 581
 582         /**
 583          * Add style sheets and supporting JS for diff display.
 584          */
 585         function showDiffStyle() {
 586                 global $wgOut;
 587                 $wgOut->addModules( 'mediawiki.legacy.diff' );
 588         }
 589
 590         /**
 591          * Get complete diff table, including header
 592          *
 593          * @param $otitle Title: old title
 594          * @param $ntitle Title: new title
 595          * @param $notice String: HTML between diff header and body
 596          * @return mixed
 597          */
 598         function getDiff( $otitle, $ntitle, $notice = '' ) {
 599                 $body = $this->getDiffBody();
 600                 if ( $body === false ) {
 601                         return false;
 602                 } else {
 603                         $multi = $this->getMultiNotice();
 604                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 605                 }
 606         }
 607
 608         /**
 609          * Get the diff table body, without header
 610          *
 611          * @return mixed (string/false)
 612          */
 613         public function getDiffBody() {
 614                 global $wgMemc;
 615                 wfProfileIn( __METHOD__ );
 616                 $this->mCacheHit = true;
 617                 // Check if the diff should be hidden from this user
 618                 if ( !$this->loadRevisionData() ) {
 619                         wfProfileOut( __METHOD__ );
 620                         return false;
 621                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 622                         wfProfileOut( __METHOD__ );
 623                         return false;
 624                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 625                         wfProfileOut( __METHOD__ );
 626                         return false;
 627                 }
 628                 // Short-circuit
 629                 if ( $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                         wfSuppressWarnings();
 688                         dl( 'php_wikidiff.so' );
 689                         wfRestoreWarnings();
 690                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 691                 }
 692                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 693                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 694                         wfSuppressWarnings();
 695                         wfDl( 'wikidiff2' );
 696                         wfRestoreWarnings();
 697                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 698                 }
 699         }
 700
 701         /**
 702          * Generate a diff, no caching
 703          *
 704          * @param $otext String: old text, must be already segmented
 705          * @param $ntext String: new text, must be already segmented
 706          */
 707         function generateDiffBody( $otext, $ntext ) {
 708                 global $wgExternalDiffEngine, $wgContLang;
 709
 710                 $otext = str_replace( "\r\n", "\n", $otext );
 711                 $ntext = str_replace( "\r\n", "\n", $ntext );
 712
 713                 $this->initDiffEngines();
 714
 715                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 716                         # For historical reasons, external diff engine expects
 717                         # input text to be HTML-escaped already
 718                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 719                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 720                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 721                         $this->debug( 'wikidiff1' );
 722                 }
 723
 724                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 725                         # Better external diff engine, the 2 may some day be dropped
 726                         # This one does the escaping and segmenting itself
 727                         wfProfileIn( 'wikidiff2_do_diff' );
 728                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 729                         $text .= $this->debug( 'wikidiff2' );
 730                         wfProfileOut( 'wikidiff2_do_diff' );
 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                 $this->debug();
 773         }
 774
 775         /**
 776          * Generate a debug comment indicating diff generating time,
 777          * server node, and generator backend.
 778          */
 779         protected function debug( $generator = "internal" ) {
 780                 global $wgShowHostnames;
 781                 if ( !$this->enableDebugComment ) {
 782                         return '';
 783                 }
 784                 $data = array( $generator );
 785                 if ( $wgShowHostnames ) {
 786                         $data[] = wfHostname();
 787                 }
 788                 $data[] = wfTimestamp( TS_DB );
 789                 return "<!-- diff generator: " .
 790                 implode( " ",
 791                 array_map(
 792                                         "htmlspecialchars",
 793                 $data ) ) .
 794                         " -->\n";
 795         }
 796
 797         /**
 798          * Replace line numbers with the text in the user's language
 799          */
 800         function localiseLineNumbers( $text ) {
 801                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 802                 array( &$this, 'localiseLineNumbersCb' ), $text );
 803         }
 804
 805         function localiseLineNumbersCb( $matches ) {
 806                 global $wgLang;
 807                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 808                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 809         }
 810
 811
 812         /**
 813          * If there are revisions between the ones being compared, return a note saying so.
 814          * @return string
 815          */
 816         function getMultiNotice() {
 817                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 818                         return '';
 819                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 820                         // Comparing two different pages? Count would be meaningless.
 821                         return '';
 822                 }
 823
 824                 $oldid = $this->mOldRev->getId();
 825                 $newid = $this->mNewRev->getId();
 826                 if ( $oldid > $newid ) {
 827                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 828                 }
 829
 830                 $nEdits = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 831                 if ( $nEdits > 0 ) {
 832                         $limit = 100;
 833                         // We use ($limit + 1) so we can detect if there are > 100 authors
 834                         // in a given revision range. In that case, diff-multi-manyusers is used.
 835                         $numUsers = $this->mTitle->countAuthorsBetween( $oldid, $newid, $limit + 1 );
 836                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 837                 }
 838                 return ''; // nothing
 839         }
 840
 841         /**
 842          * Get a notice about how many intermediate edits and users there are
 843          * @param $numEdits int
 844          * @param $numUsers int
 845          * @param $limit int
 846          * @return string
 847          */
 848         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 849                 global $wgLang;
 850                 if ( $numUsers > $limit ) {
 851                         $msg = 'diff-multi-manyusers';
 852                         $numUsers = $limit;
 853                 } else {
 854                         $msg = 'diff-multi';
 855                 }
 856                 return wfMsgExt( $msg, 'parseinline',
 857                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 858         }
 859
 860         /**
 861          * Add the header to a diff body
 862          */
 863         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 864                 $header = "<table class='diff'>";
 865                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 866                         $header .= "
 867                         <col class='diff-marker' />
 868                         <col class='diff-content' />
 869                         <col class='diff-marker' />
 870                         <col class='diff-content' />";
 871                         $colspan = 2;
 872                         $multiColspan = 4;
 873                 } else {
 874                         $colspan = 1;
 875                         $multiColspan = 2;
 876                 }
 877                 $header .= "
 878                 <tr valign='top'>
 879                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 880                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 881                 </tr>";
 882
 883                 if ( $multi != '' ) {
 884                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 885                 }
 886                 if ( $notice != '' ) {
 887                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 888                 }
 889
 890                 return $header . $diff . "</table>";
 891         }
 892
 893         /**
 894          * Use specified text instead of loading from the database
 895          */
 896         function setText( $oldText, $newText ) {
 897                 $this->mOldtext = $oldText;
 898                 $this->mNewtext = $newText;
 899                 $this->mTextLoaded = 2;
 900                 $this->mRevisionsLoaded = true;
 901         }
 902
 903         /**
 904          * Load revision metadata for the specified articles. If newid is 0, then compare
 905          * the old article in oldid to the current article; if oldid is 0, then
 906          * compare the current article to the immediately previous one (ignoring the
 907          * value of newid).
 908          *
 909          * If oldid is false, leave the corresponding revision object set
 910          * to false. This is impossible via ordinary user input, and is provided for
 911          * API convenience.
 912          */
 913         function loadRevisionData() {
 914                 global $wgLang, $wgUser;
 915                 if ( $this->mRevisionsLoaded ) {
 916                         return true;
 917                 } else {
 918                         // Whether it succeeds or fails, we don't want to try again
 919                         $this->mRevisionsLoaded = true;
 920                 }
 921
 922                 // Load the new revision object
 923                 $this->mNewRev = $this->mNewid
 924                         ? Revision::newFromId( $this->mNewid )
 925                         : Revision::newFromTitle( $this->mTitle );
 926                 if ( !$this->mNewRev instanceof Revision )
 927                         return false;
 928
 929                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 930                 $this->mNewid = $this->mNewRev->getId();
 931
 932                 // Check if page is editable
 933                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 934
 935                 // Set assorted variables
 936                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 937                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 938                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 939                 $this->mNewPage = $this->mNewRev->getTitle();
 940                 if ( $this->mNewRev->isCurrent() ) {
 941                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 942                                 'oldid' => $this->mNewid
 943                         ) );
 944                         $this->mPagetitle = htmlspecialchars( wfMsg(
 945                                 'currentrev-asof',
 946                                 $timestamp,
 947                                 $dateofrev,
 948                                 $timeofrev
 949                         ) );
 950                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 951                                 'action' => 'edit'
 952                         ) );
 953
 954                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 955                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 956                 } else {
 957                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 958                                 'oldid' => $this->mNewid
 959                         ) );
 960                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 961                                 'action' => 'edit',
 962                                 'oldid' => $this->mNewid
 963                         ) );
 964                         $this->mPagetitle = htmlspecialchars( wfMsg(
 965                                 'revisionasof',
 966                                 $timestamp,
 967                                 $dateofrev,
 968                                 $timeofrev
 969                         ) );
 970
 971                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 972                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 973                 }
 974                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 975                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 976                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 977                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 978                 }
 979
 980                 // Load the old revision object
 981                 $this->mOldRev = false;
 982                 if ( $this->mOldid ) {
 983                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 984                 } elseif ( $this->mOldid === 0 ) {
 985                         $rev = $this->mNewRev->getPrevious();
 986                         if ( $rev ) {
 987                                 $this->mOldid = $rev->getId();
 988                                 $this->mOldRev = $rev;
 989                         } else {
 990                                 // No previous revision; mark to show as first-version only.
 991                                 $this->mOldid = false;
 992                                 $this->mOldRev = false;
 993                         }
 994                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
 995
 996                 if ( is_null( $this->mOldRev ) ) {
 997                         return false;
 998                 }
 999
1000                 if ( $this->mOldRev ) {
1001                         $this->mOldPage = $this->mOldRev->getTitle();
1002
1003                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1004                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1005                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1006                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1007                                 'oldid' => $this->mOldid
1008                         ) );
1009                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1010                                 'action' => 'edit',
1011                                 'oldid' => $this->mOldid
1012                         ) );
1013                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1014
1015                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1016                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1017                         // Add an "undo" link
1018                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
1019                                 'action' => 'edit',
1020                                 'undoafter' => $this->mOldid,
1021                                 'undo' => $this->mNewid
1022                         ) );
1023                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
1024                         $htmlTitle = Xml::expandAttributes( array( 'title' => $wgUser->getSkin()->titleAttrib( 'undo' ) ) );
1025                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1026                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
1027                         }
1028
1029                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1030                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1031                         } else if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1032                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1033                         }
1034                 }
1035
1036                 return true;
1037         }
1038
1039         /**
1040          * Load the text of the revisions, as well as revision data.
1041          */
1042         function loadText() {
1043                 if ( $this->mTextLoaded == 2 ) {
1044                         return true;
1045                 } else {
1046                         // Whether it succeeds or fails, we don't want to try again
1047                         $this->mTextLoaded = 2;
1048                 }
1049
1050                 if ( !$this->loadRevisionData() ) {
1051                         return false;
1052                 }
1053                 if ( $this->mOldRev ) {
1054                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1055                         if ( $this->mOldtext === false ) {
1056                                 return false;
1057                         }
1058                 }
1059                 if ( $this->mNewRev ) {
1060                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1061                         if ( $this->mNewtext === false ) {
1062                                 return false;
1063                         }
1064                 }
1065                 return true;
1066         }
1067
1068         /**
1069          * Load the text of the new revision, not the old one
1070          */
1071         function loadNewText() {
1072                 if ( $this->mTextLoaded >= 1 ) {
1073                         return true;
1074                 } else {
1075                         $this->mTextLoaded = 1;
1076                 }
1077                 if ( !$this->loadRevisionData() ) {
1078                         return false;
1079                 }
1080                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1081                 return true;
1082         }
1083 }