includes/diff/DifferenceEngine.php

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