includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine
   4  *
   5  * @file
   6  * @ingroup DifferenceEngine
   7  */
   8
   9 /**
  10  * Constant to indicate diff cache compatibility.
  11  * Bump this when changing the diff formatting in a way that
  12  * fixes important bugs or such to force cached diff views to
  13  * clear.
  14  */
  15 define( 'MW_DIFF_VERSION', '1.11a' );
  16
  17 /**
  18  * @todo document
  19  * @ingroup DifferenceEngine
  20  */
  21 class DifferenceEngine {
  22         /**#@+
  23          * @private
  24          */
  25         var $mOldid, $mNewid;
  26         var $mOldtitle, $mNewtitle, $mPagetitle;
  27         var $mOldtext, $mNewtext;
  28
  29         /**
  30          * @var Title
  31          */
  32         var $mOldPage, $mNewPage, $mTitle;
  33         var $mRcidMarkPatrolled;
  34
  35         /**
  36          * @var Revision
  37          */
  38         var $mOldRev, $mNewRev;
  39         var $mRevisionsLoaded = false; // Have the revisions been loaded
  40         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  41         var $mCacheHit = false; // Was the diff fetched from cache?
  42
  43         /**
  44          * Set this to true to add debug info to the HTML output.
  45          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  46          * (bug 20601)
  47          */
  48         var $enableDebugComment = false;
  49
  50         // If true, line X is not displayed when X is 1, for example to increase
  51         // readability and conserve space with many small diffs.
  52         protected $mReducedLineNumbers = false;
  53
  54         protected $unhide = false; # show rev_deleted content if allowed
  55         /**#@-*/
  56
  57         /**
  58          * Constructor
  59          * @param $titleObj Title object that the diff is associated with
  60          * @param $old Integer: old ID we want to show and diff with.
  61          * @param $new String: either 'prev' or 'next'.
  62          * @param $rcid Integer: ??? FIXME (default 0)
  63          * @param $refreshCache boolean If set, refreshes the diff cache
  64          * @param $unhide boolean If set, allow viewing deleted revs
  65          */
  66         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  67                 $refreshCache = false, $unhide = false )
  68         {
  69                 if ( $titleObj ) {
  70                         $this->mTitle = $titleObj;
  71                 } else {
  72                         global $wgTitle;
  73                         $this->mTitle = $wgTitle; // @TODO: get rid of this
  74                 }
  75                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  76
  77                 if ( 'prev' === $new ) {
  78                         # Show diff between revision $old and the previous one.
  79                         # Get previous one from DB.
  80                         $this->mNewid = intval( $old );
  81                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  82                 } elseif ( 'next' === $new ) {
  83                         # Show diff between revision $old and the next one.
  84                         # Get next one from DB.
  85                         $this->mOldid = intval( $old );
  86                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  87                         if ( false === $this->mNewid ) {
  88                                 # if no result, NewId points to the newest old revision. The only newer
  89                                 # revision is cur, which is "0".
  90                                 $this->mNewid = 0;
  91                         }
  92                 } else {
  93                         $this->mOldid = intval( $old );
  94                         $this->mNewid = intval( $new );
  95                         wfRunHooks( 'NewDifferenceEngine', array( &$titleObj, &$this->mOldid, &$this->mNewid, $old, $new ) );
  96                 }
  97                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  98                 $this->mRefreshCache = $refreshCache;
  99                 $this->unhide = $unhide;
 100         }
 101
 102         function setReducedLineNumbers( $value = true ) {
 103                 $this->mReducedLineNumbers = $value;
 104         }
 105
 106         function getTitle() {
 107                 return $this->mTitle;
 108         }
 109
 110         function wasCacheHit() {
 111                 return $this->mCacheHit;
 112         }
 113
 114         function getOldid() {
 115                 return $this->mOldid;
 116         }
 117
 118         function getNewid() {
 119                 return $this->mNewid;
 120         }
 121
 122         function showDiffPage( $diffOnly = false ) {
 123                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol;
 124                 wfProfileIn( __METHOD__ );
 125
 126                 # Allow frames except in certain special cases
 127                 $wgOut->allowClickjacking();
 128
 129                 # If external diffs are enabled both globally and for the user,
 130                 # we'll use the application/x-external-editor interface to call
 131                 # an external diff tool like kompare, kdiff3, etc.
 132                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 133                         global $wgInputEncoding, $wgServer, $wgScript, $wgLang;
 134                         $wgOut->disable();
 135                         header ( "Content-type: application/x-external-editor; charset=" . $wgInputEncoding );
 136                         $url1 = $this->mTitle->getFullURL( array(
 137                                 'action' => 'raw',
 138                                 'oldid' => $this->mOldid
 139                         ) );
 140                         $url2 = $this->mTitle->getFullURL( array(
 141                                 'action' => 'raw',
 142                                 'oldid' => $this->mNewid
 143                         ) );
 144                         $special = $wgLang->getNsText( NS_SPECIAL );
 145                         $control = <<<CONTROL
 146                         [Process]
 147                         Type=Diff text
 148                         Engine=MediaWiki
 149                         Script={$wgServer}{$wgScript}
 150                         Special namespace={$special}
 151
 152                         [File]
 153                         Extension=wiki
 154                         URL=$url1
 155
 156                         [File 2]
 157                         Extension=wiki
 158                         URL=$url2
 159 CONTROL;
 160                         echo( $control );
 161
 162                         wfProfileOut( __METHOD__ );
 163                         return;
 164                 }
 165
 166                 $wgOut->setArticleFlag( false );
 167                 if ( !$this->loadRevisionData() ) {
 168                         $t = $this->mTitle->getPrefixedText();
 169                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 170                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 171                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 172                         wfProfileOut( __METHOD__ );
 173                         return;
 174                 }
 175
 176                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 177
 178                 if ( $this->mNewRev->isCurrent() ) {
 179                         $wgOut->setArticleFlag( true );
 180                 }
 181
 182                 # mOldid is false if the difference engine is called with a "vague" query for
 183                 # a diff between a version V and its previous version V' AND the version V
 184                 # is the first version of that article. In that case, V' does not exist.
 185                 if ( $this->mOldid === false ) {
 186                         $this->showFirstRevision();
 187                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 188                         wfProfileOut( __METHOD__ );
 189                         return;
 190                 }
 191
 192                 $oldTitle = $this->mOldPage->getPrefixedText();
 193                 $newTitle = $this->mNewPage->getPrefixedText();
 194                 if ( $oldTitle == $newTitle ) {
 195                         $wgOut->setPageTitle( $newTitle );
 196                 } else {
 197                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 198                 }
 199                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 200                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 201                 } else {
 202                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 203                 }
 204                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 205
 206                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 207                         $wgOut->loginToUse();
 208                         $wgOut->output();
 209                         $wgOut->disable();
 210                         wfProfileOut( __METHOD__ );
 211                         return;
 212                 }
 213
 214                 $sk = $wgUser->getSkin();
 215                 if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 216                         $sk->suppressQuickbar();
 217                 }
 218
 219                 // Check if page is editable
 220                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 221                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 222                         $wgOut->preventClickjacking();
 223                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 224                 } else {
 225                         $rollback = '';
 226                 }
 227
 228                 // Prepare a change patrol link, if applicable
 229                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 230                         // If we've been given an explicit change identifier, use it; saves time
 231                         if ( $this->mRcidMarkPatrolled ) {
 232                                 $rcid = $this->mRcidMarkPatrolled;
 233                                 $rc = RecentChange::newFromId( $rcid );
 234                                 // Already patrolled?
 235                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 236                         } else {
 237                                 // Look for an unpatrolled change corresponding to this diff
 238                                 $db = wfGetDB( DB_SLAVE );
 239                                 $change = RecentChange::newFromConds(
 240                                         array(
 241                                         // Redundant user,timestamp condition so we can use the existing index
 242                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 243                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 244                                                 'rc_this_oldid' => $this->mNewid,
 245                                                 'rc_last_oldid' => $this->mOldid,
 246                                                 'rc_patrolled'  => 0
 247                                         ),
 248                                         __METHOD__
 249                                 );
 250                                 if ( $change instanceof RecentChange ) {
 251                                         $rcid = $change->mAttribs['rc_id'];
 252                                         $this->mRcidMarkPatrolled = $rcid;
 253                                 } else {
 254                                         // None found
 255                                         $rcid = 0;
 256                                 }
 257                         }
 258                         // Build the link
 259                         if ( $rcid ) {
 260                                 $wgOut->preventClickjacking();
 261                                 $token = $wgUser->editToken( $rcid );
 262                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 263                                         $this->mTitle,
 264                                         wfMsgHtml( 'markaspatrolleddiff' ),
 265                                         array(),
 266                                         array(
 267                                                 'action' => 'markpatrolled',
 268                                                 'rcid' => $rcid,
 269                                                 'token' => $token,
 270                                         ),
 271                                         array(
 272                                                 'known',
 273                                                 'noclasses'
 274                                         )
 275                                 ) . ']</span>';
 276                         } else {
 277                                 $patrol = '';
 278                         }
 279                 } else {
 280                         $patrol = '';
 281                 }
 282
 283                 # Carry over 'diffonly' param via navigation links
 284                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 285                         $query['diffonly'] = $diffOnly;
 286                 }
 287
 288                 # Make "previous revision link"
 289                 $query['diff'] = 'prev';
 290                 $query['oldid'] = $this->mOldid;
 291                 # Cascade unhide param in links for easy deletion browsing
 292                 if ( $this->unhide ) {
 293                         $query['unhide'] = 1;
 294                 }
 295                 if ( !$this->mOldRev->getPrevious() ) {
 296                         $prevlink = '&#160;';
 297                 } else {
 298                         $prevlink = $sk->link(
 299                                 $this->mTitle,
 300                                 wfMsgHtml( 'previousdiff' ),
 301                                 array(
 302                                         'id' => 'differences-prevlink'
 303                                 ),
 304                                 $query,
 305                                 array(
 306                                         'known',
 307                                         'noclasses'
 308                                 )
 309                         );
 310                 }
 311
 312                 # Make "next revision link"
 313                 $query['diff'] = 'next';
 314                 $query['oldid'] = $this->mNewid;
 315                 # Skip next link on the top revision
 316                 if ( $this->mNewRev->isCurrent() ) {
 317                         $nextlink = '&#160;';
 318                 } else {
 319                         $nextlink = $sk->link(
 320                                 $this->mTitle,
 321                                 wfMsgHtml( 'nextdiff' ),
 322                                 array(
 323                                         'id' => 'differences-nextlink'
 324                                 ),
 325                                 $query,
 326                                 array(
 327                                         'known',
 328                                         'noclasses'
 329                                 )
 330                         );
 331                 }
 332
 333                 $oldminor = '';
 334                 $newminor = '';
 335
 336                 if ( $this->mOldRev->isMinor() ) {
 337                         $oldminor = ChangesList::flag( 'minor' );
 338                 }
 339                 if ( $this->mNewRev->isMinor() ) {
 340                         $newminor = ChangesList::flag( 'minor' );
 341                 }
 342
 343                 # Handle RevisionDelete links...
 344                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 345                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 346
 347                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 348                         '<div id="mw-diff-otitle2">' .
 349                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 350                         '<div id="mw-diff-otitle3">' . $oldminor .
 351                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 352                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 353                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 354                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 355                                 " $rollback</div>" .
 356                         '<div id="mw-diff-ntitle3">' . $newminor .
 357                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 358                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 359
 360                 # Check if this user can see the revisions
 361                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 362                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 363                 # Check if one of the revisions is deleted/suppressed
 364                 $deleted = $suppressed = false;
 365                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 366                         $deleted = true; // old revisions text is hidden
 367                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 368                                 $suppressed = true; // also suppressed
 369                 }
 370                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 371                         $deleted = true; // new revisions text is hidden
 372                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 373                                 $suppressed = true; // also suppressed
 374                 }
 375                 # If the diff cannot be shown due to a deleted revision, then output
 376                 # the diff header and links to unhide (if available)...
 377                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 378                         $this->showDiffStyle();
 379                         $multi = $this->getMultiNotice();
 380                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 381                         if ( !$allowed ) {
 382                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 383                                 # Give explanation for why revision is not visible
 384                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 385                                         array( $msg ) );
 386                         } else {
 387                                 # Give explanation and add a link to view the diff...
 388                                 $link = $this->mTitle->getFullUrl( array(
 389                                         'diff' => $this->mNewid,
 390                                         'oldid' => $this->mOldid,
 391                                         'unhide' => 1
 392                                 ) );
 393                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 394                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 395                         }
 396                 # Otherwise, output a regular diff...
 397                 } else {
 398                         # Add deletion notice if the user is viewing deleted content
 399                         $notice = '';
 400                         if ( $deleted ) {
 401                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 402                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 403                         }
 404                         $this->showDiff( $oldHeader, $newHeader, $notice );
 405                         if ( !$diffOnly ) {
 406                                 $this->renderNewRevision();
 407                         }
 408                 }
 409                 wfProfileOut( __METHOD__ );
 410         }
 411
 412         /**
 413          * @param $rev Revision
 414          * @return String
 415          */
 416         protected function revisionDeleteLink( $rev ) {
 417                 global $wgUser;
 418                 $link = '';
 419                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 420                 // Show del/undel link if:
 421                 // (a) the user can delete revisions, or
 422                 // (b) the user can view deleted revision *and* this one is deleted
 423                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 424                         $sk = $wgUser->getSkin();
 425                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 426                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 427                         } else {
 428                                 $query = array(
 429                                         'type'   => 'revision',
 430                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 431                                         'ids'    => $rev->getId()
 432                                 );
 433                                 $link = $sk->revDeleteLink( $query,
 434                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 435                         }
 436                         $link = '&#160;&#160;&#160;' . $link . ' ';
 437                 }
 438                 return $link;
 439         }
 440
 441         /**
 442          * Show the new revision of the page.
 443          */
 444         function renderNewRevision() {
 445                 global $wgOut, $wgUser;
 446                 wfProfileIn( __METHOD__ );
 447                 # Add "current version as of X" title
 448                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 449                 # Page content may be handled by a hooked call instead...
 450                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 451                         # Use the current version parser cache if applicable
 452                         $pCache = true;
 453                         if ( !$this->mNewRev->isCurrent() ) {
 454                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 455                                 $pCache = false;
 456                         }
 457
 458                         $this->loadNewText();
 459                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 460
 461                         if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 462                                 // Stolen from Article::view --AG 2007-10-11
 463                                 // Give hooks a chance to customise the output
 464                                 // @TODO: standardize this crap into one function
 465                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 466                                         // Wrap the whole lot in a <pre> and don't parse
 467                                         $m = array();
 468                                         preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 469                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 470                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 471                                         $wgOut->addHTML( "\n</pre>\n" );
 472                                 }
 473                         } elseif ( $pCache ) {
 474                                 $article = new Article( $this->mTitle, 0 );
 475                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 476                                 if( $pOutput ) {
 477                                         $wgOut->addParserOutput( $pOutput );
 478                                 } else {
 479                                         $article->doViewParse();
 480                                 }
 481                         } else {
 482                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 483                         }
 484
 485                         if ( !$this->mNewRev->isCurrent() ) {
 486                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 487                         }
 488                 }
 489                 # Add redundant patrol link on bottom...
 490                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 491                         $sk = $wgUser->getSkin();
 492                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 493                         $wgOut->preventClickjacking();
 494                         $wgOut->addHTML(
 495                                 "<div class='patrollink'>[" . $sk->link(
 496                                         $this->mTitle,
 497                                         wfMsgHtml( 'markaspatrolleddiff' ),
 498                                         array(),
 499                                         array(
 500                                                 'action'        => 'markpatrolled',
 501                                                 'rcid'          => $this->mRcidMarkPatrolled,
 502                                                 'token'         => $token,
 503                                         )
 504                                 ) . ']</div>'
 505                          );
 506                 }
 507
 508                 wfProfileOut( __METHOD__ );
 509         }
 510
 511         /**
 512          * Show the first revision of an article. Uses normal diff headers in
 513          * contrast to normal "old revision" display style.
 514          */
 515         function showFirstRevision() {
 516                 global $wgOut, $wgUser;
 517                 wfProfileIn( __METHOD__ );
 518
 519                 # Get article text from the DB
 520                 #
 521                 if ( ! $this->loadNewText() ) {
 522                         $t = $this->mTitle->getPrefixedText();
 523                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 524                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 525                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 526                         wfProfileOut( __METHOD__ );
 527                         return;
 528                 }
 529                 if ( $this->mNewRev->isCurrent() ) {
 530                         $wgOut->setArticleFlag( true );
 531                 }
 532
 533                 # Check if user is allowed to look at this page. If not, bail out.
 534                 #
 535                 if ( !$this->mTitle->userCanRead() ) {
 536                         $wgOut->loginToUse();
 537                         $wgOut->output();
 538                         wfProfileOut( __METHOD__ );
 539                         throw new MWException( "Permission Error: you do not have access to view this page" );
 540                 }
 541
 542                 # Prepare the header box
 543                 #
 544                 $sk = $wgUser->getSkin();
 545
 546                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 547                 if ( !$next ) {
 548                         $nextlink = '';
 549                 } else {
 550                         $nextlink = '<br />' . $sk->link(
 551                                 $this->mTitle,
 552                                 wfMsgHtml( 'nextdiff' ),
 553                                 array(
 554                                         'id' => 'differences-nextlink'
 555                                 ),
 556                                 array(
 557                                         'diff' => 'next',
 558                                         'oldid' => $this->mNewid,
 559                                 ),
 560                                 array(
 561                                         'known',
 562                                         'noclasses'
 563                                 )
 564                         );
 565                 }
 566                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 567                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 568
 569                 $wgOut->addHTML( $header );
 570
 571                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 572                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 573
 574                 wfProfileOut( __METHOD__ );
 575         }
 576
 577         /**
 578          * Get the diff text, send it to $wgOut
 579          * Returns false if the diff could not be generated, otherwise returns true
 580          */
 581         function showDiff( $otitle, $ntitle, $notice = '' ) {
 582                 global $wgOut;
 583                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 584                 if ( $diff === false ) {
 585                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 586                         return false;
 587                 } else {
 588                         $this->showDiffStyle();
 589                         $wgOut->addHTML( $diff );
 590                         return true;
 591                 }
 592         }
 593
 594         /**
 595          * Add style sheets and supporting JS for diff display.
 596          */
 597         function showDiffStyle() {
 598                 global $wgOut;
 599                 $wgOut->addModuleStyles( 'mediawiki.legacy.diff' );
 600                 $wgOut->addModuleScripts( 'mediawiki.legacy.diff' );
 601         }
 602
 603         /**
 604          * Get complete diff table, including header
 605          *
 606          * @param $otitle Title: old title
 607          * @param $ntitle Title: new title
 608          * @param $notice String: HTML between diff header and body
 609          * @return mixed
 610          */
 611         function getDiff( $otitle, $ntitle, $notice = '' ) {
 612                 $body = $this->getDiffBody();
 613                 if ( $body === false ) {
 614                         return false;
 615                 } else {
 616                         $multi = $this->getMultiNotice();
 617                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 618                 }
 619         }
 620
 621         /**
 622          * Get the diff table body, without header
 623          *
 624          * @return mixed (string/false)
 625          */
 626         public function getDiffBody() {
 627                 global $wgMemc;
 628                 wfProfileIn( __METHOD__ );
 629                 $this->mCacheHit = true;
 630                 // Check if the diff should be hidden from this user
 631                 if ( !$this->loadRevisionData() ) {
 632                         wfProfileOut( __METHOD__ );
 633                         return false;
 634                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 635                         wfProfileOut( __METHOD__ );
 636                         return false;
 637                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 638                         wfProfileOut( __METHOD__ );
 639                         return false;
 640                 }
 641                 // Short-circuit
 642                 if ( $this->mOldRev && $this->mNewRev
 643                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 644                 {
 645                         wfProfileOut( __METHOD__ );
 646                         return '';
 647                 }
 648                 // Cacheable?
 649                 $key = false;
 650                 if ( $this->mOldid && $this->mNewid ) {
 651                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 652                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 653                         // Try cache
 654                         if ( !$this->mRefreshCache ) {
 655                                 $difftext = $wgMemc->get( $key );
 656                                 if ( $difftext ) {
 657                                         wfIncrStats( 'diff_cache_hit' );
 658                                         $difftext = $this->localiseLineNumbers( $difftext );
 659                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 660                                         wfProfileOut( __METHOD__ );
 661                                         return $difftext;
 662                                 }
 663                         } // don't try to load but save the result
 664                 }
 665                 $this->mCacheHit = false;
 666
 667                 // Loadtext is permission safe, this just clears out the diff
 668                 if ( !$this->loadText() ) {
 669                         wfProfileOut( __METHOD__ );
 670                         return false;
 671                 }
 672
 673                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 674
 675                 // Save to cache for 7 days
 676                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 677                         wfIncrStats( 'diff_uncacheable' );
 678                 } elseif ( $key !== false && $difftext !== false ) {
 679                         wfIncrStats( 'diff_cache_miss' );
 680                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 681                 } else {
 682                         wfIncrStats( 'diff_uncacheable' );
 683                 }
 684                 // Replace line numbers with the text in the user's language
 685                 if ( $difftext !== false ) {
 686                         $difftext = $this->localiseLineNumbers( $difftext );
 687                 }
 688                 wfProfileOut( __METHOD__ );
 689                 return $difftext;
 690         }
 691
 692         /**
 693          * Make sure the proper modules are loaded before we try to
 694          * make the diff
 695          */
 696         private function initDiffEngines() {
 697                 global $wgExternalDiffEngine;
 698                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 699                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 700                         wfDl( 'php_wikidiff' );
 701                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 702                 }
 703                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 704                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 705                         wfDl( 'wikidiff2' );
 706                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 707                 }
 708         }
 709
 710         /**
 711          * Generate a diff, no caching
 712          *
 713          * @param $otext String: old text, must be already segmented
 714          * @param $ntext String: new text, must be already segmented
 715          */
 716         function generateDiffBody( $otext, $ntext ) {
 717                 global $wgExternalDiffEngine, $wgContLang;
 718
 719                 $otext = str_replace( "\r\n", "\n", $otext );
 720                 $ntext = str_replace( "\r\n", "\n", $ntext );
 721
 722                 $this->initDiffEngines();
 723
 724                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 725                         # For historical reasons, external diff engine expects
 726                         # input text to be HTML-escaped already
 727                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 728                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 729                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 730                         $this->debug( 'wikidiff1' );
 731                 }
 732
 733                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 734                         # Better external diff engine, the 2 may some day be dropped
 735                         # This one does the escaping and segmenting itself
 736                         wfProfileIn( 'wikidiff2_do_diff' );
 737                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 738                         $text .= $this->debug( 'wikidiff2' );
 739                         wfProfileOut( 'wikidiff2_do_diff' );
 740                         return $text;
 741                 }
 742                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 743                         # Diff via the shell
 744                         global $wgTmpDirectory;
 745                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 746                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 747
 748                         $tempFile1 = fopen( $tempName1, "w" );
 749                         if ( !$tempFile1 ) {
 750                                 wfProfileOut( __METHOD__ );
 751                                 return false;
 752                         }
 753                         $tempFile2 = fopen( $tempName2, "w" );
 754                         if ( !$tempFile2 ) {
 755                                 wfProfileOut( __METHOD__ );
 756                                 return false;
 757                         }
 758                         fwrite( $tempFile1, $otext );
 759                         fwrite( $tempFile2, $ntext );
 760                         fclose( $tempFile1 );
 761                         fclose( $tempFile2 );
 762                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 763                         wfProfileIn( __METHOD__ . "-shellexec" );
 764                         $difftext = wfShellExec( $cmd );
 765                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 766                         wfProfileOut( __METHOD__ . "-shellexec" );
 767                         unlink( $tempName1 );
 768                         unlink( $tempName2 );
 769                         wfProfileOut( __METHOD__ );
 770                         return $difftext;
 771                 }
 772
 773                 # Native PHP diff
 774                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 775                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 776                 $diffs = new Diff( $ota, $nta );
 777                 $formatter = new TableDiffFormatter();
 778                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 779                 wfProfileOut( __METHOD__ );
 780                 return $difftext;
 781         }
 782
 783         /**
 784          * Generate a debug comment indicating diff generating time,
 785          * server node, and generator backend.
 786          */
 787         protected function debug( $generator = "internal" ) {
 788                 global $wgShowHostnames;
 789                 if ( !$this->enableDebugComment ) {
 790                         return '';
 791                 }
 792                 $data = array( $generator );
 793                 if ( $wgShowHostnames ) {
 794                         $data[] = wfHostname();
 795                 }
 796                 $data[] = wfTimestamp( TS_DB );
 797                 return "<!-- diff generator: " .
 798                 implode( " ",
 799                 array_map(
 800                                         "htmlspecialchars",
 801                 $data ) ) .
 802                         " -->\n";
 803         }
 804
 805         /**
 806          * Replace line numbers with the text in the user's language
 807          */
 808         function localiseLineNumbers( $text ) {
 809                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 810                 array( &$this, 'localiseLineNumbersCb' ), $text );
 811         }
 812
 813         function localiseLineNumbersCb( $matches ) {
 814                 global $wgLang;
 815                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 816                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 817         }
 818
 819
 820         /**
 821          * If there are revisions between the ones being compared, return a note saying so.
 822          * @return string
 823          */
 824         function getMultiNotice() {
 825                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 826                         return '';
 827                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 828                         // Comparing two different pages? Count would be meaningless.
 829                         return '';
 830                 }
 831
 832                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 833                         $oldRev = $this->mNewRev; // flip
 834                         $newRev = $this->mOldRev; // flip
 835                 } else { // normal case
 836                         $oldRev = $this->mOldRev;
 837                         $newRev = $this->mNewRev;
 838                 }
 839
 840                 $nEdits = $this->mTitle->countRevisionsBetween( $oldRev, $newRev );
 841                 if ( $nEdits > 0 ) {
 842                         $limit = 100; // use diff-multi-manyusers if too many users
 843                         $numUsers = $this->mTitle->countAuthorsBetween( $oldRev, $newRev, $limit );
 844                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 845                 }
 846                 return ''; // nothing
 847         }
 848
 849         /**
 850          * Get a notice about how many intermediate edits and users there are
 851          * @param $numEdits int
 852          * @param $numUsers int
 853          * @param $limit int
 854          * @return string
 855          */
 856         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 857                 global $wgLang;
 858                 if ( $numUsers > $limit ) {
 859                         $msg = 'diff-multi-manyusers';
 860                         $numUsers = $limit;
 861                 } else {
 862                         $msg = 'diff-multi';
 863                 }
 864                 return wfMsgExt( $msg, 'parseinline',
 865                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 866         }
 867
 868         /**
 869          * Add the header to a diff body
 870          */
 871         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 872                 $header = "<table class='diff'>";
 873                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 874                         $header .= "
 875                         <col class='diff-marker' />
 876                         <col class='diff-content' />
 877                         <col class='diff-marker' />
 878                         <col class='diff-content' />";
 879                         $colspan = 2;
 880                         $multiColspan = 4;
 881                 } else {
 882                         $colspan = 1;
 883                         $multiColspan = 2;
 884                 }
 885                 $header .= "
 886                 <tr valign='top'>
 887                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 888                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 889                 </tr>";
 890
 891                 if ( $multi != '' ) {
 892                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 893                 }
 894                 if ( $notice != '' ) {
 895                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 896                 }
 897
 898                 return $header . $diff . "</table>";
 899         }
 900
 901         /**
 902          * Use specified text instead of loading from the database
 903          */
 904         function setText( $oldText, $newText ) {
 905                 $this->mOldtext = $oldText;
 906                 $this->mNewtext = $newText;
 907                 $this->mTextLoaded = 2;
 908                 $this->mRevisionsLoaded = true;
 909         }
 910
 911         /**
 912          * Load revision metadata for the specified articles. If newid is 0, then compare
 913          * the old article in oldid to the current article; if oldid is 0, then
 914          * compare the current article to the immediately previous one (ignoring the
 915          * value of newid).
 916          *
 917          * If oldid is false, leave the corresponding revision object set
 918          * to false. This is impossible via ordinary user input, and is provided for
 919          * API convenience.
 920          */
 921         function loadRevisionData() {
 922                 global $wgLang, $wgUser;
 923                 if ( $this->mRevisionsLoaded ) {
 924                         return true;
 925                 } else {
 926                         // Whether it succeeds or fails, we don't want to try again
 927                         $this->mRevisionsLoaded = true;
 928                 }
 929
 930                 // Load the new revision object
 931                 $this->mNewRev = $this->mNewid
 932                         ? Revision::newFromId( $this->mNewid )
 933                         : Revision::newFromTitle( $this->mTitle );
 934                 if ( !$this->mNewRev instanceof Revision )
 935                         return false;
 936
 937                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 938                 $this->mNewid = $this->mNewRev->getId();
 939
 940                 // Check if page is editable
 941                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 942
 943                 // Set assorted variables
 944                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 945                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 946                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 947                 $this->mNewPage = $this->mNewRev->getTitle();
 948                 if ( $this->mNewRev->isCurrent() ) {
 949                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 950                                 'oldid' => $this->mNewid
 951                         ) );
 952                         $this->mPagetitle = htmlspecialchars( wfMsg(
 953                                 'currentrev-asof',
 954                                 $timestamp,
 955                                 $dateofrev,
 956                                 $timeofrev
 957                         ) );
 958                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 959                                 'action' => 'edit'
 960                         ) );
 961
 962                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 963                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 964                 } else {
 965                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 966                                 'oldid' => $this->mNewid
 967                         ) );
 968                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 969                                 'action' => 'edit',
 970                                 'oldid' => $this->mNewid
 971                         ) );
 972                         $this->mPagetitle = htmlspecialchars( wfMsg(
 973                                 'revisionasof',
 974                                 $timestamp,
 975                                 $dateofrev,
 976                                 $timeofrev
 977                         ) );
 978
 979                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 980                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 981                 }
 982                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 983                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 984                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 985                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 986                 }
 987
 988                 // Load the old revision object
 989                 $this->mOldRev = false;
 990                 if ( $this->mOldid ) {
 991                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 992                 } elseif ( $this->mOldid === 0 ) {
 993                         $rev = $this->mNewRev->getPrevious();
 994                         if ( $rev ) {
 995                                 $this->mOldid = $rev->getId();
 996                                 $this->mOldRev = $rev;
 997                         } else {
 998                                 // No previous revision; mark to show as first-version only.
 999                                 $this->mOldid = false;
1000                                 $this->mOldRev = false;
1001                         }
1002                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1003
1004                 if ( is_null( $this->mOldRev ) ) {
1005                         return false;
1006                 }
1007
1008                 if ( $this->mOldRev ) {
1009                         $this->mOldPage = $this->mOldRev->getTitle();
1010
1011                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1012                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1013                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1014                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1015                                 'oldid' => $this->mOldid
1016                         ) );
1017                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1018                                 'action' => 'edit',
1019                                 'oldid' => $this->mOldid
1020                         ) );
1021                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1022
1023                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1024                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1025                         // Add an "undo" link
1026                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1027                                 $undoLink = Html::element( 'a', array(
1028                                         'href' => $this->mNewPage->getLocalUrl( array(
1029                                                 'action' => 'edit',
1030                                                 'undoafter' => $this->mOldid,
1031                                                 'undo' => $this->mNewid ) ),
1032                                         'title' => $wgUser->getSkin()->titleAttrib( 'undo' )
1033                                 ), wfMsg( 'editundo' ) );
1034                                 $this->mNewtitle .= ' (' . $undoLink . ')';
1035                         }
1036
1037                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1038                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1039                         } else if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1040                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1041                         }
1042                 }
1043
1044                 return true;
1045         }
1046
1047         /**
1048          * Load the text of the revisions, as well as revision data.
1049          */
1050         function loadText() {
1051                 if ( $this->mTextLoaded == 2 ) {
1052                         return true;
1053                 } else {
1054                         // Whether it succeeds or fails, we don't want to try again
1055                         $this->mTextLoaded = 2;
1056                 }
1057
1058                 if ( !$this->loadRevisionData() ) {
1059                         return false;
1060                 }
1061                 if ( $this->mOldRev ) {
1062                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1063                         if ( $this->mOldtext === false ) {
1064                                 return false;
1065                         }
1066                 }
1067                 if ( $this->mNewRev ) {
1068                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1069                         if ( $this->mNewtext === false ) {
1070                                 return false;
1071                         }
1072                 }
1073                 return true;
1074         }
1075
1076         /**
1077          * Load the text of the new revision, not the old one
1078          */
1079         function loadNewText() {
1080                 if ( $this->mTextLoaded >= 1 ) {
1081                         return true;
1082                 } else {
1083                         $this->mTextLoaded = 1;
1084                 }
1085                 if ( !$this->loadRevisionData() ) {
1086                         return false;
1087                 }
1088                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1089                 return true;
1090         }
1091 }