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->addModuleStyles( 'mediawiki.legacy.diff' );
 588                 $wgOut->addModuleScripts( '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                         wfProfileOut( __METHOD__ );
 621                         return false;
 622                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 623                         wfProfileOut( __METHOD__ );
 624                         return false;
 625                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 626                         wfProfileOut( __METHOD__ );
 627                         return false;
 628                 }
 629                 // Short-circuit
 630                 if ( $this->mOldRev && $this->mNewRev
 631                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 632                 {
 633                         wfProfileOut( __METHOD__ );
 634                         return '';
 635                 }
 636                 // Cacheable?
 637                 $key = false;
 638                 if ( $this->mOldid && $this->mNewid ) {
 639                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 640                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 641                         // Try cache
 642                         if ( !$this->mRefreshCache ) {
 643                                 $difftext = $wgMemc->get( $key );
 644                                 if ( $difftext ) {
 645                                         wfIncrStats( 'diff_cache_hit' );
 646                                         $difftext = $this->localiseLineNumbers( $difftext );
 647                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 648                                         wfProfileOut( __METHOD__ );
 649                                         return $difftext;
 650                                 }
 651                         } // don't try to load but save the result
 652                 }
 653                 $this->mCacheHit = false;
 654
 655                 // Loadtext is permission safe, this just clears out the diff
 656                 if ( !$this->loadText() ) {
 657                         wfProfileOut( __METHOD__ );
 658                         return false;
 659                 }
 660
 661                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 662
 663                 // Save to cache for 7 days
 664                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 665                         wfIncrStats( 'diff_uncacheable' );
 666                 } elseif ( $key !== false && $difftext !== false ) {
 667                         wfIncrStats( 'diff_cache_miss' );
 668                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 669                 } else {
 670                         wfIncrStats( 'diff_uncacheable' );
 671                 }
 672                 // Replace line numbers with the text in the user's language
 673                 if ( $difftext !== false ) {
 674                         $difftext = $this->localiseLineNumbers( $difftext );
 675                 }
 676                 wfProfileOut( __METHOD__ );
 677                 return $difftext;
 678         }
 679
 680         /**
 681          * Make sure the proper modules are loaded before we try to
 682          * make the diff
 683          */
 684         private function initDiffEngines() {
 685                 global $wgExternalDiffEngine;
 686                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 687                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 688                         wfSuppressWarnings();
 689                         dl( 'php_wikidiff.so' );
 690                         wfRestoreWarnings();
 691                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 692                 }
 693                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 694                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 695                         wfSuppressWarnings();
 696                         wfDl( 'wikidiff2' );
 697                         wfRestoreWarnings();
 698                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 699                 }
 700         }
 701
 702         /**
 703          * Generate a diff, no caching
 704          *
 705          * @param $otext String: old text, must be already segmented
 706          * @param $ntext String: new text, must be already segmented
 707          */
 708         function generateDiffBody( $otext, $ntext ) {
 709                 global $wgExternalDiffEngine, $wgContLang;
 710
 711                 $otext = str_replace( "\r\n", "\n", $otext );
 712                 $ntext = str_replace( "\r\n", "\n", $ntext );
 713
 714                 $this->initDiffEngines();
 715
 716                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 717                         # For historical reasons, external diff engine expects
 718                         # input text to be HTML-escaped already
 719                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 720                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 721                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 722                         $this->debug( 'wikidiff1' );
 723                 }
 724
 725                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 726                         # Better external diff engine, the 2 may some day be dropped
 727                         # This one does the escaping and segmenting itself
 728                         wfProfileIn( 'wikidiff2_do_diff' );
 729                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 730                         $text .= $this->debug( 'wikidiff2' );
 731                         wfProfileOut( 'wikidiff2_do_diff' );
 732                         return $text;
 733                 }
 734                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 735                         # Diff via the shell
 736                         global $wgTmpDirectory;
 737                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 738                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 739
 740                         $tempFile1 = fopen( $tempName1, "w" );
 741                         if ( !$tempFile1 ) {
 742                                 wfProfileOut( __METHOD__ );
 743                                 return false;
 744                         }
 745                         $tempFile2 = fopen( $tempName2, "w" );
 746                         if ( !$tempFile2 ) {
 747                                 wfProfileOut( __METHOD__ );
 748                                 return false;
 749                         }
 750                         fwrite( $tempFile1, $otext );
 751                         fwrite( $tempFile2, $ntext );
 752                         fclose( $tempFile1 );
 753                         fclose( $tempFile2 );
 754                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 755                         wfProfileIn( __METHOD__ . "-shellexec" );
 756                         $difftext = wfShellExec( $cmd );
 757                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 758                         wfProfileOut( __METHOD__ . "-shellexec" );
 759                         unlink( $tempName1 );
 760                         unlink( $tempName2 );
 761                         wfProfileOut( __METHOD__ );
 762                         return $difftext;
 763                 }
 764
 765                 # Native PHP diff
 766                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 767                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 768                 $diffs = new Diff( $ota, $nta );
 769                 $formatter = new TableDiffFormatter();
 770                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 771                 wfProfileOut( __METHOD__ );
 772                 return $difftext;
 773                 $this->debug();
 774         }
 775
 776         /**
 777          * Generate a debug comment indicating diff generating time,
 778          * server node, and generator backend.
 779          */
 780         protected function debug( $generator = "internal" ) {
 781                 global $wgShowHostnames;
 782                 if ( !$this->enableDebugComment ) {
 783                         return '';
 784                 }
 785                 $data = array( $generator );
 786                 if ( $wgShowHostnames ) {
 787                         $data[] = wfHostname();
 788                 }
 789                 $data[] = wfTimestamp( TS_DB );
 790                 return "<!-- diff generator: " .
 791                 implode( " ",
 792                 array_map(
 793                                         "htmlspecialchars",
 794                 $data ) ) .
 795                         " -->\n";
 796         }
 797
 798         /**
 799          * Replace line numbers with the text in the user's language
 800          */
 801         function localiseLineNumbers( $text ) {
 802                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 803                 array( &$this, 'localiseLineNumbersCb' ), $text );
 804         }
 805
 806         function localiseLineNumbersCb( $matches ) {
 807                 global $wgLang;
 808                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 809                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 810         }
 811
 812
 813         /**
 814          * If there are revisions between the ones being compared, return a note saying so.
 815          * @return string
 816          */
 817         function getMultiNotice() {
 818                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 819                         return '';
 820                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 821                         // Comparing two different pages? Count would be meaningless.
 822                         return '';
 823                 }
 824
 825                 $oldid = $this->mOldRev->getId();
 826                 $newid = $this->mNewRev->getId();
 827                 if ( $oldid > $newid ) {
 828                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 829                 }
 830
 831                 $nEdits = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 832                 if ( $nEdits > 0 ) {
 833                         $limit = 100;
 834                         // We use ($limit + 1) so we can detect if there are > 100 authors
 835                         // in a given revision range. In that case, diff-multi-manyusers is used.
 836                         $numUsers = $this->mTitle->countAuthorsBetween( $oldid, $newid, $limit + 1 );
 837                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 838                 }
 839                 return ''; // nothing
 840         }
 841
 842         /**
 843          * Get a notice about how many intermediate edits and users there are
 844          * @param $numEdits int
 845          * @param $numUsers int
 846          * @param $limit int
 847          * @return string
 848          */
 849         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 850                 global $wgLang;
 851                 if ( $numUsers > $limit ) {
 852                         $msg = 'diff-multi-manyusers';
 853                         $numUsers = $limit;
 854                 } else {
 855                         $msg = 'diff-multi';
 856                 }
 857                 return wfMsgExt( $msg, 'parseinline',
 858                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 859         }
 860
 861         /**
 862          * Add the header to a diff body
 863          */
 864         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 865                 $header = "<table class='diff'>";
 866                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 867                         $header .= "
 868                         <col class='diff-marker' />
 869                         <col class='diff-content' />
 870                         <col class='diff-marker' />
 871                         <col class='diff-content' />";
 872                         $colspan = 2;
 873                         $multiColspan = 4;
 874                 } else {
 875                         $colspan = 1;
 876                         $multiColspan = 2;
 877                 }
 878                 $header .= "
 879                 <tr valign='top'>
 880                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 881                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 882                 </tr>";
 883
 884                 if ( $multi != '' ) {
 885                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 886                 }
 887                 if ( $notice != '' ) {
 888                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 889                 }
 890
 891                 return $header . $diff . "</table>";
 892         }
 893
 894         /**
 895          * Use specified text instead of loading from the database
 896          */
 897         function setText( $oldText, $newText ) {
 898                 $this->mOldtext = $oldText;
 899                 $this->mNewtext = $newText;
 900                 $this->mTextLoaded = 2;
 901                 $this->mRevisionsLoaded = true;
 902         }
 903
 904         /**
 905          * Load revision metadata for the specified articles. If newid is 0, then compare
 906          * the old article in oldid to the current article; if oldid is 0, then
 907          * compare the current article to the immediately previous one (ignoring the
 908          * value of newid).
 909          *
 910          * If oldid is false, leave the corresponding revision object set
 911          * to false. This is impossible via ordinary user input, and is provided for
 912          * API convenience.
 913          */
 914         function loadRevisionData() {
 915                 global $wgLang, $wgUser;
 916                 if ( $this->mRevisionsLoaded ) {
 917                         return true;
 918                 } else {
 919                         // Whether it succeeds or fails, we don't want to try again
 920                         $this->mRevisionsLoaded = true;
 921                 }
 922
 923                 // Load the new revision object
 924                 $this->mNewRev = $this->mNewid
 925                         ? Revision::newFromId( $this->mNewid )
 926                         : Revision::newFromTitle( $this->mTitle );
 927                 if ( !$this->mNewRev instanceof Revision )
 928                         return false;
 929
 930                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 931                 $this->mNewid = $this->mNewRev->getId();
 932
 933                 // Check if page is editable
 934                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 935
 936                 // Set assorted variables
 937                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 938                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 939                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 940                 $this->mNewPage = $this->mNewRev->getTitle();
 941                 if ( $this->mNewRev->isCurrent() ) {
 942                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 943                                 'oldid' => $this->mNewid
 944                         ) );
 945                         $this->mPagetitle = htmlspecialchars( wfMsg(
 946                                 'currentrev-asof',
 947                                 $timestamp,
 948                                 $dateofrev,
 949                                 $timeofrev
 950                         ) );
 951                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 952                                 'action' => 'edit'
 953                         ) );
 954
 955                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 956                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 957                 } else {
 958                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 959                                 'oldid' => $this->mNewid
 960                         ) );
 961                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 962                                 'action' => 'edit',
 963                                 'oldid' => $this->mNewid
 964                         ) );
 965                         $this->mPagetitle = htmlspecialchars( wfMsg(
 966                                 'revisionasof',
 967                                 $timestamp,
 968                                 $dateofrev,
 969                                 $timeofrev
 970                         ) );
 971
 972                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 973                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 974                 }
 975                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 976                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 977                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 978                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 979                 }
 980
 981                 // Load the old revision object
 982                 $this->mOldRev = false;
 983                 if ( $this->mOldid ) {
 984                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 985                 } elseif ( $this->mOldid === 0 ) {
 986                         $rev = $this->mNewRev->getPrevious();
 987                         if ( $rev ) {
 988                                 $this->mOldid = $rev->getId();
 989                                 $this->mOldRev = $rev;
 990                         } else {
 991                                 // No previous revision; mark to show as first-version only.
 992                                 $this->mOldid = false;
 993                                 $this->mOldRev = false;
 994                         }
 995                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
 996
 997                 if ( is_null( $this->mOldRev ) ) {
 998                         return false;
 999                 }
1000
1001                 if ( $this->mOldRev ) {
1002                         $this->mOldPage = $this->mOldRev->getTitle();
1003
1004                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1005                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1006                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1007                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1008                                 'oldid' => $this->mOldid
1009                         ) );
1010                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1011                                 'action' => 'edit',
1012                                 'oldid' => $this->mOldid
1013                         ) );
1014                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1015
1016                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1017                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1018                         // Add an "undo" link
1019                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
1020                                 'action' => 'edit',
1021                                 'undoafter' => $this->mOldid,
1022                                 'undo' => $this->mNewid
1023                         ) );
1024                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
1025                         $htmlTitle = Xml::expandAttributes( array( 'title' => $wgUser->getSkin()->titleAttrib( 'undo' ) ) );
1026                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1027                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
1028                         }
1029
1030                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1031                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1032                         } else if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1033                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1034                         }
1035                 }
1036
1037                 return true;
1038         }
1039
1040         /**
1041          * Load the text of the revisions, as well as revision data.
1042          */
1043         function loadText() {
1044                 if ( $this->mTextLoaded == 2 ) {
1045                         return true;
1046                 } else {
1047                         // Whether it succeeds or fails, we don't want to try again
1048                         $this->mTextLoaded = 2;
1049                 }
1050
1051                 if ( !$this->loadRevisionData() ) {
1052                         return false;
1053                 }
1054                 if ( $this->mOldRev ) {
1055                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1056                         if ( $this->mOldtext === false ) {
1057                                 return false;
1058                         }
1059                 }
1060                 if ( $this->mNewRev ) {
1061                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1062                         if ( $this->mNewtext === false ) {
1063                                 return false;
1064                         }
1065                 }
1066                 return true;
1067         }
1068
1069         /**
1070          * Load the text of the new revision, not the old one
1071          */
1072         function loadNewText() {
1073                 if ( $this->mTextLoaded >= 1 ) {
1074                         return true;
1075                 } else {
1076                         $this->mTextLoaded = 1;
1077                 }
1078                 if ( !$this->loadRevisionData() ) {
1079                         return false;
1080                 }
1081                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1082                 return true;
1083         }
1084 }