includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine
   4  *
   5  * @file
   6  * @ingroup DifferenceEngine
   7  */
   8
   9 /**
  10  * Constant to indicate diff cache compatibility.
  11  * Bump this when changing the diff formatting in a way that
  12  * fixes important bugs or such to force cached diff views to
  13  * clear.
  14  */
  15 define( 'MW_DIFF_VERSION', '1.11a' );
  16
  17 /**
  18  * @todo document
  19  * @ingroup DifferenceEngine
  20  */
  21 class DifferenceEngine {
  22         /**#@+
  23          * @private
  24          */
  25         var $mOldid, $mNewid, $mTitle;
  26         var $mOldtitle, $mNewtitle, $mPagetitle;
  27         var $mOldtext, $mNewtext;
  28         var $mOldPage, $mNewPage;
  29         var $mRcidMarkPatrolled;
  30         var $mOldRev, $mNewRev;
  31         var $mRevisionsLoaded = false; // Have the revisions been loaded
  32         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  33         var $mCacheHit = false; // Was the diff fetched from cache?
  34
  35         /**
  36          * Set this to true to add debug info to the HTML output.
  37          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  38          * (bug 20601)
  39          */
  40         var $enableDebugComment = false;
  41
  42         // If true, line X is not displayed when X is 1, for example to increase
  43         // readability and conserve space with many small diffs.
  44         protected $mReducedLineNumbers = false;
  45
  46         protected $unhide = false; # show rev_deleted content if allowed
  47         /**#@-*/
  48
  49         /**
  50          * Constructor
  51          * @param $titleObj Title object that the diff is associated with
  52          * @param $old Integer: old ID we want to show and diff with.
  53          * @param $new String: either 'prev' or 'next'.
  54          * @param $rcid Integer: ??? FIXME (default 0)
  55          * @param $refreshCache boolean If set, refreshes the diff cache
  56          * @param $unhide boolean If set, allow viewing deleted revs
  57          */
  58         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  59                 $refreshCache = false, $unhide = false )
  60         {
  61                 if ( $titleObj ) {
  62                         $this->mTitle = $titleObj;
  63                 } else {
  64                         global $wgTitle;
  65                         $this->mTitle = $wgTitle;
  66                 }
  67                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  68
  69                 if ( 'prev' === $new ) {
  70                         # Show diff between revision $old and the previous one.
  71                         # Get previous one from DB.
  72                         $this->mNewid = intval( $old );
  73                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  74                 } elseif ( 'next' === $new ) {
  75                         # Show diff between revision $old and the next one.
  76                         # Get next one from DB.
  77                         $this->mOldid = intval( $old );
  78                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  79                         if ( false === $this->mNewid ) {
  80                                 # if no result, NewId points to the newest old revision. The only newer
  81                                 # revision is cur, which is "0".
  82                                 $this->mNewid = 0;
  83                         }
  84                 } else {
  85                         $this->mOldid = intval( $old );
  86                         $this->mNewid = intval( $new );
  87                         wfRunHooks( 'NewDifferenceEngine', array( &$titleObj, &$this->mOldid, &$this->mNewid, $old, $new ) );
  88                 }
  89                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  90                 $this->mRefreshCache = $refreshCache;
  91                 $this->unhide = $unhide;
  92         }
  93
  94         function setReducedLineNumbers( $value = true ) {
  95                 $this->mReducedLineNumbers = $value;
  96         }
  97
  98         function getTitle() {
  99                 return $this->mTitle;
 100         }
 101
 102         function wasCacheHit() {
 103                 return $this->mCacheHit;
 104         }
 105
 106         function getOldid() {
 107                 return $this->mOldid;
 108         }
 109
 110         function getNewid() {
 111                 return $this->mNewid;
 112         }
 113
 114         function showDiffPage( $diffOnly = false ) {
 115                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol;
 116                 wfProfileIn( __METHOD__ );
 117
 118
 119                 # If external diffs are enabled both globally and for the user,
 120                 # we'll use the application/x-external-editor interface to call
 121                 # an external diff tool like kompare, kdiff3, etc.
 122                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 123                         global $wgInputEncoding, $wgServer, $wgScript, $wgLang;
 124                         $wgOut->disable();
 125                         header ( "Content-type: application/x-external-editor; charset=" . $wgInputEncoding );
 126                         $url1 = $this->mTitle->getFullURL( array(
 127                                 'action' => 'raw',
 128                                 'oldid' => $this->mOldid
 129                         ) );
 130                         $url2 = $this->mTitle->getFullURL( array(
 131                                 'action' => 'raw',
 132                                 'oldid' => $this->mNewid
 133                         ) );
 134                         $special = $wgLang->getNsText( NS_SPECIAL );
 135                         $control = <<<CONTROL
 136                         [Process]
 137                         Type=Diff text
 138                         Engine=MediaWiki
 139                         Script={$wgServer}{$wgScript}
 140                         Special namespace={$special}
 141
 142                         [File]
 143                         Extension=wiki
 144                         URL=$url1
 145
 146                         [File 2]
 147                         Extension=wiki
 148                         URL=$url2
 149 CONTROL;
 150                         echo( $control );
 151                         return;
 152                 }
 153
 154                 $wgOut->setArticleFlag( false );
 155                 if ( !$this->loadRevisionData() ) {
 156                         $t = $this->mTitle->getPrefixedText();
 157                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 158                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 159                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 160                         wfProfileOut( __METHOD__ );
 161                         return;
 162                 }
 163
 164                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 165
 166                 if ( $this->mNewRev->isCurrent() ) {
 167                         $wgOut->setArticleFlag( true );
 168                 }
 169
 170                 # mOldid is false if the difference engine is called with a "vague" query for
 171                 # a diff between a version V and its previous version V' AND the version V
 172                 # is the first version of that article. In that case, V' does not exist.
 173                 if ( $this->mOldid === false ) {
 174                         $this->showFirstRevision();
 175                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 176                         wfProfileOut( __METHOD__ );
 177                         return;
 178                 }
 179
 180                 $wgOut->suppressQuickbar();
 181
 182                 $oldTitle = $this->mOldPage->getPrefixedText();
 183                 $newTitle = $this->mNewPage->getPrefixedText();
 184                 if ( $oldTitle == $newTitle ) {
 185                         $wgOut->setPageTitle( $newTitle );
 186                 } else {
 187                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 188                 }
 189                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 190                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 191                 } else {
 192                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 193                 }
 194                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 195
 196                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 197                         $wgOut->loginToUse();
 198                         $wgOut->output();
 199                         $wgOut->disable();
 200                         wfProfileOut( __METHOD__ );
 201                         return;
 202                 }
 203
 204                 $sk = $wgUser->getSkin();
 205
 206                 // Check if page is editable
 207                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 208                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 209                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 210                 } else {
 211                         $rollback = '';
 212                 }
 213
 214                 // Prepare a change patrol link, if applicable
 215                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 216                         // If we've been given an explicit change identifier, use it; saves time
 217                         if ( $this->mRcidMarkPatrolled ) {
 218                                 $rcid = $this->mRcidMarkPatrolled;
 219                                 $rc = RecentChange::newFromId( $rcid );
 220                                 // Already patrolled?
 221                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 222                         } else {
 223                                 // Look for an unpatrolled change corresponding to this diff
 224                                 $db = wfGetDB( DB_SLAVE );
 225                                 $change = RecentChange::newFromConds(
 226                                         array(
 227                                         // Redundant user,timestamp condition so we can use the existing index
 228                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 229                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 230                                                 'rc_this_oldid' => $this->mNewid,
 231                                                 'rc_last_oldid' => $this->mOldid,
 232                                                 'rc_patrolled'  => 0
 233                                         ),
 234                                         __METHOD__
 235                                 );
 236                                 if ( $change instanceof RecentChange ) {
 237                                         $rcid = $change->mAttribs['rc_id'];
 238                                         $this->mRcidMarkPatrolled = $rcid;
 239                                 } else {
 240                                         // None found
 241                                         $rcid = 0;
 242                                 }
 243                         }
 244                         // Build the link
 245                         if ( $rcid ) {
 246                                 $token = $wgUser->editToken( $rcid );
 247                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 248                                         $this->mTitle,
 249                                         wfMsgHtml( 'markaspatrolleddiff' ),
 250                                         array(),
 251                                         array(
 252                                                 'action' => 'markpatrolled',
 253                                                 'rcid' => $rcid,
 254                                                 'token' => $token,
 255                                         ),
 256                                         array(
 257                                                 'known',
 258                                                 'noclasses'
 259                                         )
 260                                 ) . ']</span>';
 261                         } else {
 262                                 $patrol = '';
 263                         }
 264                 } else {
 265                         $patrol = '';
 266                 }
 267
 268                 # Carry over 'diffonly' param via navigation links
 269                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 270                         $query['diffonly'] = $diffOnly;
 271                 }
 272
 273                 # Make "previous revision link"
 274                 $query['diff'] = 'prev';
 275                 $query['oldid'] = $this->mOldid;
 276                 # Cascade unhide param in links for easy deletion browsing
 277                 if ( $this->unhide ) {
 278                         $query['unhide'] = 1;
 279                 }
 280                 if ( !$this->mOldRev->getPrevious() ) {
 281                         $prevlink = '&#160;';
 282                 } else {
 283                         $prevlink = $sk->link(
 284                                 $this->mTitle,
 285                                 wfMsgHtml( 'previousdiff' ),
 286                                 array(
 287                                         'id' => 'differences-prevlink'
 288                                 ),
 289                                 $query,
 290                                 array(
 291                                         'known',
 292                                         'noclasses'
 293                                 )
 294                         );
 295                 }
 296
 297                 # Make "next revision link"
 298                 $query['diff'] = 'next';
 299                 $query['oldid'] = $this->mNewid;
 300                 # Skip next link on the top revision
 301                 if ( $this->mNewRev->isCurrent() ) {
 302                         $nextlink = '&#160;';
 303                 } else {
 304                         $nextlink = $sk->link(
 305                                 $this->mTitle,
 306                                 wfMsgHtml( 'nextdiff' ),
 307                                 array(
 308                                         'id' => 'differences-nextlink'
 309                                 ),
 310                                 $query,
 311                                 array(
 312                                         'known',
 313                                         'noclasses'
 314                                 )
 315                         );
 316                 }
 317
 318                 $oldminor = '';
 319                 $newminor = '';
 320
 321                 if ( $this->mOldRev->isMinor() ) {
 322                         $oldminor = ChangesList::flag( 'minor' );
 323                 }
 324                 if ( $this->mNewRev->isMinor() ) {
 325                         $newminor = ChangesList::flag( 'minor' );
 326                 }
 327
 328                 # Handle RevisionDelete links...
 329                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 330                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 331
 332                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 333                         '<div id="mw-diff-otitle2">' .
 334                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 335                         '<div id="mw-diff-otitle3">' . $oldminor .
 336                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 337                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 338                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 339                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 340                                 " $rollback</div>" .
 341                         '<div id="mw-diff-ntitle3">' . $newminor .
 342                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 343                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 344
 345                 # Check if this user can see the revisions
 346                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 347                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 348                 # Check if one of the revisions is deleted/suppressed
 349                 $deleted = $suppressed = false;
 350                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 351                         $deleted = true; // old revisions text is hidden
 352                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 353                                 $suppressed = true; // also suppressed
 354                 }
 355                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 356                         $deleted = true; // new revisions text is hidden
 357                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 358                                 $suppressed = true; // also suppressed
 359                 }
 360                 # If the diff cannot be shown due to a deleted revision, then output
 361                 # the diff header and links to unhide (if available)...
 362                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 363                         $this->showDiffStyle();
 364                         $multi = $this->getMultiNotice();
 365                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 366                         if ( !$allowed ) {
 367                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 368                                 # Give explanation for why revision is not visible
 369                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
 370                                         array( $msg ) );
 371                         } else {
 372                                 # Give explanation and add a link to view the diff...
 373                                 $link = $this->mTitle->getFullUrl( array(
 374                                         'diff' => $this->mNewid,
 375                                         'oldid' => $this->mOldid,
 376                                         'unhide' => 1
 377                                 ) );
 378                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 379                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 380                         }
 381                 # Otherwise, output a regular diff...
 382                 } else {
 383                         # Add deletion notice if the user is viewing deleted content
 384                         $notice = '';
 385                         if ( $deleted ) {
 386                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 387                                 $notice = "<div class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 388                         }
 389                         $this->showDiff( $oldHeader, $newHeader, $notice );
 390                         if ( !$diffOnly ) {
 391                                 $this->renderNewRevision();
 392                         }
 393                 }
 394                 wfProfileOut( __METHOD__ );
 395         }
 396
 397         protected function revisionDeleteLink( $rev ) {
 398                 global $wgUser;
 399                 $link = '';
 400                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 401                 // Show del/undel link if:
 402                 // (a) the user can delete revisions, or
 403                 // (b) the user can view deleted revision *and* this one is deleted
 404                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 405                         $sk = $wgUser->getSkin();
 406                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 407                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 408                         } else {
 409                                 $query = array(
 410                                         'type'   => 'revision',
 411                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 412                                         'ids'    => $rev->getId()
 413                                 );
 414                                 $link = $sk->revDeleteLink( $query,
 415                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 416                         }
 417                         $link = '&#160;&#160;&#160;' . $link . ' ';
 418                 }
 419                 return $link;
 420         }
 421
 422         /**
 423          * Show the new revision of the page.
 424          */
 425         function renderNewRevision() {
 426                 global $wgOut, $wgUser;
 427                 wfProfileIn( __METHOD__ );
 428
 429                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 430                 # Add deleted rev tag if needed
 431                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 432                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", 'rev-deleted-text-permission' );
 433                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 434                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", 'rev-deleted-text-view' );
 435                 }
 436
 437                 $pCache = true;
 438                 if ( !$this->mNewRev->isCurrent() ) {
 439                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 440                         $pCache = false;
 441                 }
 442
 443                 $this->loadNewText();
 444                 if ( is_object( $this->mNewRev ) ) {
 445                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 446                 }
 447
 448                 if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 449                         // Stolen from Article::view --AG 2007-10-11
 450                         // Give hooks a chance to customise the output
 451                         if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 452                                 // Wrap the whole lot in a <pre> and don't parse
 453                                 $m = array();
 454                                 preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 455                                 $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 456                                 $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 457                                 $wgOut->addHTML( "\n</pre>\n" );
 458                         }
 459                 } elseif ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 460                         if ( $pCache ) {
 461                                 $article = new Article( $this->mTitle, 0 );
 462                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 463                                 if ( $pOutput ) {
 464                                         $wgOut->addParserOutput( $pOutput );
 465                                 } else {
 466                                         $article->doViewParse();
 467                                 }
 468                         } else {
 469                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 470                         }
 471                 } else {
 472                         $article = new Article( $this->mTitle, 0 );
 473                         $pOutput = $article->getParserOutput();
 474                         $wgOut->addParserOutputNoText( $pOutput );
 475                 }
 476
 477                 if ( is_object( $this->mNewRev ) && !$this->mNewRev->isCurrent() ) {
 478                         $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 479                 }
 480
 481                 # Add redundant patrol link on bottom...
 482                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 483                         $sk = $wgUser->getSkin();
 484                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 485                         $wgOut->addHTML(
 486                                 "<div class='patrollink'>[" . $sk->link(
 487                                         $this->mTitle,
 488                                         wfMsgHtml( 'markaspatrolleddiff' ),
 489                                         array(),
 490                                         array(
 491                                                 'action' => 'markpatrolled',
 492                                                 'rcid' => $this->mRcidMarkPatrolled,
 493                                                 'token' => $token,
 494                                         )
 495                                 ) . ']</div>'
 496                          );
 497                 }
 498
 499                 wfProfileOut( __METHOD__ );
 500         }
 501
 502         /**
 503          * Show the first revision of an article. Uses normal diff headers in
 504          * contrast to normal "old revision" display style.
 505          */
 506         function showFirstRevision() {
 507                 global $wgOut, $wgUser;
 508                 wfProfileIn( __METHOD__ );
 509
 510                 # Get article text from the DB
 511                 #
 512                 if ( ! $this->loadNewText() ) {
 513                         $t = $this->mTitle->getPrefixedText();
 514                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 515                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 516                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 517                         wfProfileOut( __METHOD__ );
 518                         return;
 519                 }
 520                 if ( $this->mNewRev->isCurrent() ) {
 521                         $wgOut->setArticleFlag( true );
 522                 }
 523
 524                 # Check if user is allowed to look at this page. If not, bail out.
 525                 #
 526                 if ( !$this->mTitle->userCanRead() ) {
 527                         $wgOut->loginToUse();
 528                         $wgOut->output();
 529                         wfProfileOut( __METHOD__ );
 530                         throw new MWException( "Permission Error: you do not have access to view this page" );
 531                 }
 532
 533                 # Prepare the header box
 534                 #
 535                 $sk = $wgUser->getSkin();
 536
 537                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 538                 if ( !$next ) {
 539                         $nextlink = '';
 540                 } else {
 541                         $nextlink = '<br />' . $sk->link(
 542                                 $this->mTitle,
 543                                 wfMsgHtml( 'nextdiff' ),
 544                                 array(
 545                                         'id' => 'differences-nextlink'
 546                                 ),
 547                                 array(
 548                                         'diff' => 'next',
 549                                         'oldid' => $this->mNewid,
 550                                 ),
 551                                 array(
 552                                         'known',
 553                                         'noclasses'
 554                                 )
 555                         );
 556                 }
 557                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 558                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 559
 560                 $wgOut->addHTML( $header );
 561
 562                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 563                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 564
 565                 wfProfileOut( __METHOD__ );
 566         }
 567
 568         /**
 569          * Get the diff text, send it to $wgOut
 570          * Returns false if the diff could not be generated, otherwise returns true
 571          */
 572         function showDiff( $otitle, $ntitle, $notice = '' ) {
 573                 global $wgOut;
 574                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 575                 if ( $diff === false ) {
 576                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 577                         return false;
 578                 } else {
 579                         $this->showDiffStyle();
 580                         $wgOut->addHTML( $diff );
 581                         return true;
 582                 }
 583         }
 584
 585         /**
 586          * Add style sheets and supporting JS for diff display.
 587          */
 588         function showDiffStyle() {
 589                 global $wgOut;
 590                 $wgOut->addModules( 'mediawiki.legacy.diff' );
 591         }
 592
 593         /**
 594          * Get complete diff table, including header
 595          *
 596          * @param $otitle Title: old title
 597          * @param $ntitle Title: new title
 598          * @param $notice String: HTML between diff header and body
 599          * @return mixed
 600          */
 601         function getDiff( $otitle, $ntitle, $notice = '' ) {
 602                 $body = $this->getDiffBody();
 603                 if ( $body === false ) {
 604                         return false;
 605                 } else {
 606                         $multi = $this->getMultiNotice();
 607                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 608                 }
 609         }
 610
 611         /**
 612          * Get the diff table body, without header
 613          *
 614          * @return mixed (string/false)
 615          */
 616         public function getDiffBody() {
 617                 global $wgMemc;
 618                 wfProfileIn( __METHOD__ );
 619                 $this->mCacheHit = true;
 620                 // Check if the diff should be hidden from this user
 621                 if ( !$this->loadRevisionData() ) {
 622                         return false;
 623                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 624                         return false;
 625                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 626                         return false;
 627                 }
 628                 // Short-circuit
 629                 if ( $this->mOldRev && $this->mNewRev
 630                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 631                 {
 632                         return '';
 633                 }
 634                 // Cacheable?
 635                 $key = false;
 636                 if ( $this->mOldid && $this->mNewid ) {
 637                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 638                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 639                         // Try cache
 640                         if ( !$this->mRefreshCache ) {
 641                                 $difftext = $wgMemc->get( $key );
 642                                 if ( $difftext ) {
 643                                         wfIncrStats( 'diff_cache_hit' );
 644                                         $difftext = $this->localiseLineNumbers( $difftext );
 645                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 646                                         wfProfileOut( __METHOD__ );
 647                                         return $difftext;
 648                                 }
 649                         } // don't try to load but save the result
 650                 }
 651                 $this->mCacheHit = false;
 652
 653                 // Loadtext is permission safe, this just clears out the diff
 654                 if ( !$this->loadText() ) {
 655                         wfProfileOut( __METHOD__ );
 656                         return false;
 657                 }
 658
 659                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 660
 661                 // Save to cache for 7 days
 662                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 663                         wfIncrStats( 'diff_uncacheable' );
 664                 } elseif ( $key !== false && $difftext !== false ) {
 665                         wfIncrStats( 'diff_cache_miss' );
 666                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 667                 } else {
 668                         wfIncrStats( 'diff_uncacheable' );
 669                 }
 670                 // Replace line numbers with the text in the user's language
 671                 if ( $difftext !== false ) {
 672                         $difftext = $this->localiseLineNumbers( $difftext );
 673                 }
 674                 wfProfileOut( __METHOD__ );
 675                 return $difftext;
 676         }
 677
 678         /**
 679          * Make sure the proper modules are loaded before we try to
 680          * make the diff
 681          */
 682         private function initDiffEngines() {
 683                 global $wgExternalDiffEngine;
 684                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 685                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 686                         wfSuppressWarnings();
 687                         dl( 'php_wikidiff.so' );
 688                         wfRestoreWarnings();
 689                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 690                 }
 691                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 692                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 693                         wfSuppressWarnings();
 694                         wfDl( 'wikidiff2' );
 695                         wfRestoreWarnings();
 696                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 697                 }
 698         }
 699
 700         /**
 701          * Generate a diff, no caching
 702          *
 703          * @param $otext String: old text, must be already segmented
 704          * @param $ntext String: new text, must be already segmented
 705          */
 706         function generateDiffBody( $otext, $ntext ) {
 707                 global $wgExternalDiffEngine, $wgContLang;
 708
 709                 $otext = str_replace( "\r\n", "\n", $otext );
 710                 $ntext = str_replace( "\r\n", "\n", $ntext );
 711
 712                 $this->initDiffEngines();
 713
 714                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 715                         # For historical reasons, external diff engine expects
 716                         # input text to be HTML-escaped already
 717                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 718                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 719                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 720                         $this->debug( 'wikidiff1' );
 721                 }
 722
 723                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 724                         # Better external diff engine, the 2 may some day be dropped
 725                         # This one does the escaping and segmenting itself
 726                         wfProfileIn( 'wikidiff2_do_diff' );
 727                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 728                         $text .= $this->debug( 'wikidiff2' );
 729                         wfProfileOut( 'wikidiff2_do_diff' );
 730                         return $text;
 731                 }
 732                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 733                         # Diff via the shell
 734                         global $wgTmpDirectory;
 735                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 736                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 737
 738                         $tempFile1 = fopen( $tempName1, "w" );
 739                         if ( !$tempFile1 ) {
 740                                 wfProfileOut( __METHOD__ );
 741                                 return false;
 742                         }
 743                         $tempFile2 = fopen( $tempName2, "w" );
 744                         if ( !$tempFile2 ) {
 745                                 wfProfileOut( __METHOD__ );
 746                                 return false;
 747                         }
 748                         fwrite( $tempFile1, $otext );
 749                         fwrite( $tempFile2, $ntext );
 750                         fclose( $tempFile1 );
 751                         fclose( $tempFile2 );
 752                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 753                         wfProfileIn( __METHOD__ . "-shellexec" );
 754                         $difftext = wfShellExec( $cmd );
 755                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 756                         wfProfileOut( __METHOD__ . "-shellexec" );
 757                         unlink( $tempName1 );
 758                         unlink( $tempName2 );
 759                         return $difftext;
 760                 }
 761
 762                 # Native PHP diff
 763                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 764                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 765                 $diffs = new Diff( $ota, $nta );
 766                 $formatter = new TableDiffFormatter();
 767                 return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 768                 $this->debug();
 769         }
 770
 771         /**
 772          * Generate a debug comment indicating diff generating time,
 773          * server node, and generator backend.
 774          */
 775         protected function debug( $generator = "internal" ) {
 776                 global $wgShowHostnames;
 777                 if ( !$this->enableDebugComment ) {
 778                         return '';
 779                 }
 780                 $data = array( $generator );
 781                 if ( $wgShowHostnames ) {
 782                         $data[] = wfHostname();
 783                 }
 784                 $data[] = wfTimestamp( TS_DB );
 785                 return "<!-- diff generator: " .
 786                 implode( " ",
 787                 array_map(
 788                                         "htmlspecialchars",
 789                 $data ) ) .
 790                         " -->\n";
 791         }
 792
 793         /**
 794          * Replace line numbers with the text in the user's language
 795          */
 796         function localiseLineNumbers( $text ) {
 797                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 798                 array( &$this, 'localiseLineNumbersCb' ), $text );
 799         }
 800
 801         function localiseLineNumbersCb( $matches ) {
 802                 global $wgLang;
 803                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 804                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 805         }
 806
 807
 808         /**
 809          * If there are revisions between the ones being compared, return a note saying so.
 810          * @return string
 811          */
 812         function getMultiNotice() {
 813                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 814                         return '';
 815                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 816                         // Comparing two different pages? Count would be meaningless.
 817                         return '';
 818                 }
 819
 820                 $oldid = $this->mOldRev->getId();
 821                 $newid = $this->mNewRev->getId();
 822                 if ( $oldid > $newid ) {
 823                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 824                 }
 825
 826                 $nEdits = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 827                 if ( $nEdits > 0 ) {
 828                         $limit = 100;
 829                         // We use ($limit + 1) so we can detect if there are > 100 authors
 830                         // in a given revision range. In that case, diff-multi-manyusers is used.
 831                         $numUsers = $this->mTitle->countAuthorsBetween( $oldid, $newid, $limit + 1 );
 832                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 833                 }
 834                 return ''; // nothing
 835         }
 836
 837         /**
 838          * Get a notice about how many intermediate edits and users there are
 839          * @param $numEdits int
 840          * @param $numUsers int
 841          * @param $limit int
 842          * @return string
 843          */
 844         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 845                 global $wgLang;
 846                 if ( $numUsers > $limit ) {
 847                         $msg = 'diff-multi-manyusers';
 848                         $numUsers = $limit;
 849                 } else {
 850                         $msg = 'diff-multi';
 851                 }
 852                 return wfMsgExt( $msg, 'parseinline',
 853                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 854         }
 855
 856         /**
 857          * Add the header to a diff body
 858          */
 859         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 860                 $header = "<table class='diff'>";
 861                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 862                         $header .= "
 863                         <col class='diff-marker' />
 864                         <col class='diff-content' />
 865                         <col class='diff-marker' />
 866                         <col class='diff-content' />";
 867                         $colspan = 2;
 868                         $multiColspan = 4;
 869                 } else {
 870                         $colspan = 1;
 871                         $multiColspan = 2;
 872                 }
 873                 $header .= "
 874                 <tr valign='top'>
 875                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 876                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 877                 </tr>";
 878
 879                 if ( $multi != '' ) {
 880                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 881                 }
 882                 if ( $notice != '' ) {
 883                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 884                 }
 885
 886                 return $header . $diff . "</table>";
 887         }
 888
 889         /**
 890          * Use specified text instead of loading from the database
 891          */
 892         function setText( $oldText, $newText ) {
 893                 $this->mOldtext = $oldText;
 894                 $this->mNewtext = $newText;
 895                 $this->mTextLoaded = 2;
 896                 $this->mRevisionsLoaded = true;
 897         }
 898
 899         /**
 900          * Load revision metadata for the specified articles. If newid is 0, then compare
 901          * the old article in oldid to the current article; if oldid is 0, then
 902          * compare the current article to the immediately previous one (ignoring the
 903          * value of newid).
 904          *
 905          * If oldid is false, leave the corresponding revision object set
 906          * to false. This is impossible via ordinary user input, and is provided for
 907          * API convenience.
 908          */
 909         function loadRevisionData() {
 910                 global $wgLang, $wgUser;
 911                 if ( $this->mRevisionsLoaded ) {
 912                         return true;
 913                 } else {
 914                         // Whether it succeeds or fails, we don't want to try again
 915                         $this->mRevisionsLoaded = true;
 916                 }
 917
 918                 // Load the new revision object
 919                 $this->mNewRev = $this->mNewid
 920                         ? Revision::newFromId( $this->mNewid )
 921                         : Revision::newFromTitle( $this->mTitle );
 922                 if ( !$this->mNewRev instanceof Revision )
 923                         return false;
 924
 925                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 926                 $this->mNewid = $this->mNewRev->getId();
 927
 928                 // Check if page is editable
 929                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 930
 931                 // Set assorted variables
 932                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 933                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 934                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 935                 $this->mNewPage = $this->mNewRev->getTitle();
 936                 if ( $this->mNewRev->isCurrent() ) {
 937                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 938                                 'oldid' => $this->mNewid
 939                         ) );
 940                         $this->mPagetitle = htmlspecialchars( wfMsg(
 941                                 'currentrev-asof',
 942                                 $timestamp,
 943                                 $dateofrev,
 944                                 $timeofrev
 945                         ) );
 946                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 947                                 'action' => 'edit'
 948                         ) );
 949
 950                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 951                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 952                 } else {
 953                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 954                                 'oldid' => $this->mNewid
 955                         ) );
 956                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 957                                 'action' => 'edit',
 958                                 'oldid' => $this->mNewid
 959                         ) );
 960                         $this->mPagetitle = htmlspecialchars( wfMsg(
 961                                 'revisionasof',
 962                                 $timestamp,
 963                                 $dateofrev,
 964                                 $timeofrev
 965                         ) );
 966
 967                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 968                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 969                 }
 970                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 971                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 972                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 973                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 974                 }
 975
 976                 // Load the old revision object
 977                 $this->mOldRev = false;
 978                 if ( $this->mOldid ) {
 979                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 980                 } elseif ( $this->mOldid === 0 ) {
 981                         $rev = $this->mNewRev->getPrevious();
 982                         if ( $rev ) {
 983                                 $this->mOldid = $rev->getId();
 984                                 $this->mOldRev = $rev;
 985                         } else {
 986                                 // No previous revision; mark to show as first-version only.
 987                                 $this->mOldid = false;
 988                                 $this->mOldRev = false;
 989                         }
 990                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
 991
 992                 if ( is_null( $this->mOldRev ) ) {
 993                         return false;
 994                 }
 995
 996                 if ( $this->mOldRev ) {
 997                         $this->mOldPage = $this->mOldRev->getTitle();
 998
 999                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1000                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1001                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1002                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1003                                 'oldid' => $this->mOldid
1004                         ) );
1005                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1006                                 'action' => 'edit',
1007                                 'oldid' => $this->mOldid
1008                         ) );
1009                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1010
1011                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1012                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1013                         // Add an "undo" link
1014                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
1015                                 'action' => 'edit',
1016                                 'undoafter' => $this->mOldid,
1017                                 'undo' => $this->mNewid
1018                         ) );
1019                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
1020                         $htmlTitle = $wgUser->getSkin()->titleAttrib( 'undo' );
1021                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1022                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
1023                         }
1024
1025                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1026                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1027                         } else if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1028                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1029                         }
1030                 }
1031
1032                 return true;
1033         }
1034
1035         /**
1036          * Load the text of the revisions, as well as revision data.
1037          */
1038         function loadText() {
1039                 if ( $this->mTextLoaded == 2 ) {
1040                         return true;
1041                 } else {
1042                         // Whether it succeeds or fails, we don't want to try again
1043                         $this->mTextLoaded = 2;
1044                 }
1045
1046                 if ( !$this->loadRevisionData() ) {
1047                         return false;
1048                 }
1049                 if ( $this->mOldRev ) {
1050                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1051                         if ( $this->mOldtext === false ) {
1052                                 return false;
1053                         }
1054                 }
1055                 if ( $this->mNewRev ) {
1056                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1057                         if ( $this->mNewtext === false ) {
1058                                 return false;
1059                         }
1060                 }
1061                 return true;
1062         }
1063
1064         /**
1065          * Load the text of the new revision, not the old one
1066          */
1067         function loadNewText() {
1068                 if ( $this->mTextLoaded >= 1 ) {
1069                         return true;
1070                 } else {
1071                         $this->mTextLoaded = 1;
1072                 }
1073                 if ( !$this->loadRevisionData() ) {
1074                         return false;
1075                 }
1076                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1077                 return true;
1078         }
1079 }