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 $mOldtext, $mNewtext;
  27         protected $mDiffLang;
  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         private $mRevisionsIdsLoaded = false; // Have the revisions IDs been loaded
  40         var $mRevisionsLoaded = false; // Have the revisions been loaded
  41         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  42         var $mCacheHit = false; // Was the diff fetched from cache?
  43
  44         /**
  45          * Set this to true to add debug info to the HTML output.
  46          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  47          * (bug 20601)
  48          */
  49         var $enableDebugComment = false;
  50
  51         // If true, line X is not displayed when X is 1, for example to increase
  52         // readability and conserve space with many small diffs.
  53         protected $mReducedLineNumbers = false;
  54
  55         // Link to action=markpatrolled
  56         protected $mMarkPatrolledLink = null;
  57
  58         protected $unhide = false; # show rev_deleted content if allowed
  59         /**#@-*/
  60
  61         /**
  62          * Constructor
  63          * @param $titleObj Title object that the diff is associated with
  64          * @param $old Integer old ID we want to show and diff with.
  65          * @param $new String either 'prev' or 'next'.
  66          * @param $rcid Integer ??? FIXME (default 0)
  67          * @param $refreshCache boolean If set, refreshes the diff cache
  68          * @param $unhide boolean If set, allow viewing deleted revs
  69          */
  70         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  71                 $refreshCache = false, $unhide = false )
  72         {
  73                 if ( $titleObj ) {
  74                         $this->mTitle = $titleObj;
  75                 } else {
  76                         global $wgTitle;
  77                         $this->mTitle = $wgTitle; // @TODO: get rid of this
  78                 }
  79                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  80
  81                 $this->mOldid = $old;
  82                 $this->mNewid = $new;
  83                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  84                 $this->mRefreshCache = $refreshCache;
  85                 $this->unhide = $unhide;
  86         }
  87
  88         /**
  89          * @param $value bool
  90          */
  91         function setReducedLineNumbers( $value = true ) {
  92                 $this->mReducedLineNumbers = $value;
  93         }
  94
  95         /**
  96          * @return Language
  97          */
  98         function getDiffLang() {
  99                 if ( $this->mDiffLang === null ) {
 100                         # Default language in which the diff text is written.
 101                         $this->mDiffLang = $this->mTitle->getPageLanguage();
 102                 }
 103                 return $this->mDiffLang;
 104         }
 105
 106         /**
 107          * @return Title
 108          */
 109         function getTitle() {
 110                 return $this->mTitle;
 111         }
 112
 113         /**
 114          * @return bool
 115          */
 116         function wasCacheHit() {
 117                 return $this->mCacheHit;
 118         }
 119
 120         /**
 121          * @return int
 122          */
 123         function getOldid() {
 124                 $this->loadRevisionIds();
 125                 return $this->mOldid;
 126         }
 127
 128         /**
 129          * @return Bool|int
 130          */
 131         function getNewid() {
 132                 $this->loadRevisionIds();
 133                 return $this->mNewid;
 134         }
 135
 136         /**
 137          * Look up a special:Undelete link to the given deleted revision id,
 138          * as a workaround for being unable to load deleted diffs in currently.
 139          *
 140          * @param int $id revision ID
 141          * @return mixed URL or false
 142          */
 143         function deletedLink( $id ) {
 144                 global $wgUser;
 145                 if ( $wgUser->isAllowed( 'deletedhistory' ) ) {
 146                         $dbr = wfGetDB( DB_SLAVE );
 147                         $row = $dbr->selectRow('archive', '*',
 148                                 array( 'ar_rev_id' => $id ),
 149                                 __METHOD__ );
 150                         if ( $row ) {
 151                                 $rev = Revision::newFromArchiveRow( $row );
 152                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 153                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 154                                         'target' => $title->getPrefixedText(),
 155                                         'timestamp' => $rev->getTimestamp()
 156                                 ));
 157                         }
 158                 }
 159                 return false;
 160         }
 161
 162         /**
 163          * Build a wikitext link toward a deleted revision, if viewable.
 164          *
 165          * @param int $id revision ID
 166          * @return string wikitext fragment
 167          */
 168         function deletedIdMarker( $id ) {
 169                 $link = $this->deletedLink( $id );
 170                 if ( $link ) {
 171                         return "[$link $id]";
 172                 } else {
 173                         return $id;
 174                 }
 175         }
 176
 177         function showDiffPage( $diffOnly = false ) {
 178                 global $wgUser, $wgOut, $wgRequest, $wgUseExternalEditor;
 179                 wfProfileIn( __METHOD__ );
 180
 181                 # Allow frames except in certain special cases
 182                 $wgOut->allowClickjacking();
 183                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 184
 185                 if ( !$this->loadRevisionData() ) {
 186                         // Sounds like a deleted revision... Let's see what we can do.
 187                         $t = $this->mTitle->getPrefixedText();
 188                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 189                                 $this->deletedIdMarker( $this->mOldid ),
 190                                 $this->deletedIdMarker( $this->mNewid ) );
 191                         $wgOut->setPageTitle( wfMessage( 'errorpagetitle' ) );
 192                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 193                         wfProfileOut( __METHOD__ );
 194                         return;
 195                 }
 196
 197                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $wgUser );
 198                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 199                         $permErrors = wfMergeErrorArrays( $permErrors,
 200                                 $this->mOldPage->getUserPermissionsErrors( 'read', $wgUser ) );
 201                 }
 202                 if ( count( $permErrors ) ) {
 203                         wfProfileOut( __METHOD__ );
 204                         throw new PermissionsError( 'read', $permErrors );
 205                 }
 206
 207                 /// @todo Make RequestContext::getMain() go away when we have a context available
 208                 $context = RequestContext::getMain();
 209
 210                 # If external diffs are enabled both globally and for the user,
 211                 # we'll use the application/x-external-editor interface to call
 212                 # an external diff tool like kompare, kdiff3, etc.
 213                 if ( ExternalEdit::useExternalEngine( $context, 'diff' ) ) {
 214                         $urls = array(
 215                                 'File' => array( 'Extension' => 'wiki', 'URL' =>
 216                                         # This should be mOldPage, but it may not be set, see below.
 217                                         $this->mNewPage->getCanonicalURL( array(
 218                                                 'action' => 'raw', 'oldid' => $this->mOldid ) )
 219                                 ),
 220                                 'File2' => array( 'Extension' => 'wiki', 'URL' =>
 221                                         $this->mNewPage->getCanonicalURL( array(
 222                                                 'action' => 'raw', 'oldid' => $this->mNewid ) )
 223                                 ),
 224                         );
 225
 226                         $externalEditor = new ExternalEdit( $context, $urls );
 227                         $externalEditor->execute();
 228
 229                         wfProfileOut( __METHOD__ );
 230                         return;
 231                 }
 232
 233                 $rollback = '';
 234                 $undoLink = '';
 235
 236                 $query = array();
 237                 # Carry over 'diffonly' param via navigation links
 238                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 239                         $query['diffonly'] = $diffOnly;
 240                 }
 241                 # Cascade unhide param in links for easy deletion browsing
 242                 if ( $this->unhide ) {
 243                         $query['unhide'] = 1;
 244                 }
 245
 246                 # Check if one of the revisions is deleted/suppressed
 247                 $deleted = $suppressed = false;
 248                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT );
 249
 250                 # mOldRev is false if the difference engine is called with a "vague" query for
 251                 # a diff between a version V and its previous version V' AND the version V
 252                 # is the first version of that article. In that case, V' does not exist.
 253                 if ( $this->mOldRev === false ) {
 254                         $wgOut->setPageTitle( $this->mNewPage->getPrefixedText() );
 255                         $wgOut->addSubtitle( wfMessage( 'difference' ) );
 256                         $samePage = true;
 257                         $oldHeader = '';
 258                 } else {
 259                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 260
 261                         $sk = $wgUser->getSkin();
 262                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 263                                 $sk->suppressQuickbar();
 264                         }
 265
 266                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 267                                 $wgOut->setPageTitle( $this->mNewPage->getPrefixedText() );
 268                                 $wgOut->addSubtitle( wfMessage( 'difference' ) );
 269                                 $samePage = true;
 270                         } else {
 271                                 $wgOut->setPageTitle( $this->mOldPage->getPrefixedText() . ', ' . $this->mNewPage->getPrefixedText() );
 272                                 $wgOut->addSubtitle( wfMessage( 'difference-multipage' ) );
 273                                 $samePage = false;
 274                         }
 275
 276                         if ( $samePage && $this->mNewPage->userCan( 'edit' ) ) {
 277                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback' ) ) {
 278                                         $wgOut->preventClickjacking();
 279                                         $rollback = '&#160;&#160;&#160;' . Linker::generateRollback( $this->mNewRev );
 280                                 }
 281                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 282                                         $undoLink = ' ' . wfMsgHtml( 'parentheses', Html::element( 'a', array(
 283                                                 'href' => $this->mNewPage->getLocalUrl( array(
 284                                                         'action' => 'edit',
 285                                                         'undoafter' => $this->mOldid,
 286                                                         'undo' => $this->mNewid ) ),
 287                                                 'title' => Linker::titleAttrib( 'undo' )
 288                                         ), wfMsg( 'editundo' ) ) );
 289                                 }
 290                         }
 291
 292                         # Make "previous revision link"
 293                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 294                                 $prevlink = Linker::linkKnown(
 295                                         $this->mOldPage,
 296                                         wfMsgHtml( 'previousdiff' ),
 297                                         array( 'id' => 'differences-prevlink' ),
 298                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 299                                 );
 300                         } else {
 301                                 $prevlink = '&#160;';
 302                         }
 303
 304                         if ( $this->mOldRev->isMinor() ) {
 305                                 $oldminor = ChangesList::flag( 'minor' );
 306                         } else {
 307                                 $oldminor = '';
 308                         }
 309
 310                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 311                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 312
 313                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 314                                 '<div id="mw-diff-otitle2">' .
 315                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 316                                 '<div id="mw-diff-otitle3">' . $oldminor .
 317                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 318                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 319
 320                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 321                                 $deleted = true; // old revisions text is hidden
 322                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 323                                         $suppressed = true; // also suppressed
 324                                 }
 325                         }
 326
 327                         # Check if this user can see the revisions
 328                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 329                                 $allowed = false;
 330                         }
 331                 }
 332
 333                 # Make "next revision link"
 334                 # Skip next link on the top revision
 335                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 336                         $nextlink = Linker::linkKnown(
 337                                 $this->mNewPage,
 338                                 wfMsgHtml( 'nextdiff' ),
 339                                 array( 'id' => 'differences-nextlink' ),
 340                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 341                         );
 342                 } else {
 343                         $nextlink = '&#160;';
 344                 }
 345
 346                 if ( $this->mNewRev->isMinor() ) {
 347                         $newminor = ChangesList::flag( 'minor' );
 348                 } else {
 349                         $newminor = '';
 350                 }
 351
 352                 # Handle RevisionDelete links...
 353                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 354                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 355
 356                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 357                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 358                                 " $rollback</div>" .
 359                         '<div id="mw-diff-ntitle3">' . $newminor .
 360                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 361                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 362
 363                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 364                         $deleted = true; // new revisions text is hidden
 365                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 366                                 $suppressed = true; // also suppressed
 367                 }
 368
 369                 # If the diff cannot be shown due to a deleted revision, then output
 370                 # the diff header and links to unhide (if available)...
 371                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 372                         $this->showDiffStyle();
 373                         $multi = $this->getMultiNotice();
 374                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 375                         if ( !$allowed ) {
 376                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 377                                 # Give explanation for why revision is not visible
 378                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 379                                         array( $msg ) );
 380                         } else {
 381                                 # Give explanation and add a link to view the diff...
 382                                 $link = $this->mTitle->getFullUrl( $wgRequest->appendQueryValue( 'unhide', '1', true ) );
 383                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 384                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 385                         }
 386                 # Otherwise, output a regular diff...
 387                 } else {
 388                         # Add deletion notice if the user is viewing deleted content
 389                         $notice = '';
 390                         if ( $deleted ) {
 391                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 392                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 393                         }
 394                         $this->showDiff( $oldHeader, $newHeader, $notice );
 395                         if ( !$diffOnly ) {
 396                                 $this->renderNewRevision();
 397                         }
 398                 }
 399                 wfProfileOut( __METHOD__ );
 400         }
 401
 402         /**
 403          * Get a link to mark the change as patrolled, or '' if there's either no
 404          * revision to patrol or the user is not allowed to to it.
 405          * Side effect: this method will call OutputPage::preventClickjacking()
 406          * when a link is builded.
 407          *
 408          * @return String
 409          */
 410         protected function markPatrolledLink() {
 411                 global $wgUseRCPatrol, $wgUser, $wgOut;
 412
 413                 if ( $this->mMarkPatrolledLink === null ) {
 414                         // Prepare a change patrol link, if applicable
 415                         if ( $wgUseRCPatrol && $this->mNewPage->userCan( 'patrol' ) ) {
 416                                 // If we've been given an explicit change identifier, use it; saves time
 417                                 if ( $this->mRcidMarkPatrolled ) {
 418                                         $rcid = $this->mRcidMarkPatrolled;
 419                                         $rc = RecentChange::newFromId( $rcid );
 420                                         // Already patrolled?
 421                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 422                                 } else {
 423                                         // Look for an unpatrolled change corresponding to this diff
 424                                         $db = wfGetDB( DB_SLAVE );
 425                                         $change = RecentChange::newFromConds(
 426                                                 array(
 427                                                 // Redundant user,timestamp condition so we can use the existing index
 428                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 429                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 430                                                         'rc_this_oldid' => $this->mNewid,
 431                                                         'rc_last_oldid' => $this->mOldid,
 432                                                         'rc_patrolled'  => 0
 433                                                 ),
 434                                                 __METHOD__
 435                                         );
 436                                         if ( $change instanceof RecentChange ) {
 437                                                 $rcid = $change->mAttribs['rc_id'];
 438                                                 $this->mRcidMarkPatrolled = $rcid;
 439                                         } else {
 440                                                 // None found
 441                                                 $rcid = 0;
 442                                         }
 443                                 }
 444                                 // Build the link
 445                                 if ( $rcid ) {
 446                                         $wgOut->preventClickjacking();
 447                                         $token = $wgUser->editToken( $rcid );
 448                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 449                                                 $this->mNewPage,
 450                                                 wfMsgHtml( 'markaspatrolleddiff' ),
 451                                                 array(),
 452                                                 array(
 453                                                         'action' => 'markpatrolled',
 454                                                         'rcid' => $rcid,
 455                                                         'token' => $token,
 456                                                 )
 457                                         ) . ']</span>';
 458                                 } else {
 459                                         $this->mMarkPatrolledLink = '';
 460                                 }
 461                         } else {
 462                                 $this->mMarkPatrolledLink = '';
 463                         }
 464                 }
 465
 466                 return $this->mMarkPatrolledLink;
 467         }
 468
 469         /**
 470          * @param $rev Revision
 471          * @return String
 472          */
 473         protected function revisionDeleteLink( $rev ) {
 474                 global $wgUser;
 475                 $link = '';
 476                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 477                 // Show del/undel link if:
 478                 // (a) the user can delete revisions, or
 479                 // (b) the user can view deleted revision *and* this one is deleted
 480                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 481                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 482                                 $link = Linker::revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 483                         } else {
 484                                 $query = array(
 485                                         'type'   => 'revision',
 486                                         'target' => $rev->getTitle()->getPrefixedDBkey(),
 487                                         'ids'    => $rev->getId()
 488                                 );
 489                                 $link = Linker::revDeleteLink( $query,
 490                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 491                         }
 492                         $link = '&#160;&#160;&#160;' . $link . ' ';
 493                 }
 494                 return $link;
 495         }
 496
 497         /**
 498          * Show the new revision of the page.
 499          */
 500         function renderNewRevision() {
 501                 global $wgOut;
 502                 wfProfileIn( __METHOD__ );
 503                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 504                 # Add "current version as of X" title
 505                 $wgOut->addHTML( "<hr class='diff-hr' />
 506                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 507                 # Page content may be handled by a hooked call instead...
 508                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 509                         # Use the current version parser cache if applicable
 510                         $pCache = true;
 511                         if ( !$this->mNewRev->isCurrent() ) {
 512                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 513                                 $pCache = false;
 514                         }
 515
 516                         $this->loadNewText();
 517                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 518                         $wgOut->setArticleFlag( true );
 519
 520                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 521                                 // Stolen from Article::view --AG 2007-10-11
 522                                 // Give hooks a chance to customise the output
 523                                 // @TODO: standardize this crap into one function
 524                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mNewPage, $wgOut ) ) ) {
 525                                         // Wrap the whole lot in a <pre> and don't parse
 526                                         $m = array();
 527                                         preg_match( '!\.(css|js)$!u', $this->mNewPage->getText(), $m );
 528                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 529                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 530                                         $wgOut->addHTML( "\n</pre>\n" );
 531                                 }
 532                         } elseif ( $pCache ) {
 533                                 $article = new Article( $this->mNewPage, 0 );
 534                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 535                                 if( $pOutput ) {
 536                                         $wgOut->addParserOutput( $pOutput );
 537                                 } else {
 538                                         $article->doViewParse();
 539                                 }
 540                         } else {
 541                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 542                         }
 543
 544                         if ( !$this->mNewRev->isCurrent() ) {
 545                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 546                         }
 547                 }
 548                 # Add redundant patrol link on bottom...
 549                 $wgOut->addHTML( $this->markPatrolledLink() );
 550
 551                 wfProfileOut( __METHOD__ );
 552         }
 553
 554         /**
 555          * Get the diff text, send it to $wgOut
 556          * Returns false if the diff could not be generated, otherwise returns true
 557          *
 558          * @return bool
 559          */
 560         function showDiff( $otitle, $ntitle, $notice = '' ) {
 561                 global $wgOut;
 562                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 563                 if ( $diff === false ) {
 564                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 565                         return false;
 566                 } else {
 567                         $this->showDiffStyle();
 568                         $wgOut->addHTML( $diff );
 569                         return true;
 570                 }
 571         }
 572
 573         /**
 574          * Add style sheets and supporting JS for diff display.
 575          */
 576         function showDiffStyle() {
 577                 global $wgOut;
 578                 $wgOut->addModuleStyles( 'mediawiki.action.history.diff' );
 579         }
 580
 581         /**
 582          * Get complete diff table, including header
 583          *
 584          * @param $otitle Title: old title
 585          * @param $ntitle Title: new title
 586          * @param $notice String: HTML between diff header and body
 587          * @return mixed
 588          */
 589         function getDiff( $otitle, $ntitle, $notice = '' ) {
 590                 $body = $this->getDiffBody();
 591                 if ( $body === false ) {
 592                         return false;
 593                 } else {
 594                         $multi = $this->getMultiNotice();
 595                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 596                 }
 597         }
 598
 599         /**
 600          * Get the diff table body, without header
 601          *
 602          * @return mixed (string/false)
 603          */
 604         public function getDiffBody() {
 605                 global $wgMemc;
 606                 wfProfileIn( __METHOD__ );
 607                 $this->mCacheHit = true;
 608                 // Check if the diff should be hidden from this user
 609                 if ( !$this->loadRevisionData() ) {
 610                         wfProfileOut( __METHOD__ );
 611                         return false;
 612                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 613                         wfProfileOut( __METHOD__ );
 614                         return false;
 615                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 616                         wfProfileOut( __METHOD__ );
 617                         return false;
 618                 }
 619                 // Short-circuit
 620                 // If mOldRev is false, it means that the
 621                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 622                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 623                 {
 624                         wfProfileOut( __METHOD__ );
 625                         return '';
 626                 }
 627                 // Cacheable?
 628                 $key = false;
 629                 if ( $this->mOldid && $this->mNewid ) {
 630                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 631                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 632                         // Try cache
 633                         if ( !$this->mRefreshCache ) {
 634                                 $difftext = $wgMemc->get( $key );
 635                                 if ( $difftext ) {
 636                                         wfIncrStats( 'diff_cache_hit' );
 637                                         $difftext = $this->localiseLineNumbers( $difftext );
 638                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 639                                         wfProfileOut( __METHOD__ );
 640                                         return $difftext;
 641                                 }
 642                         } // don't try to load but save the result
 643                 }
 644                 $this->mCacheHit = false;
 645
 646                 // Loadtext is permission safe, this just clears out the diff
 647                 if ( !$this->loadText() ) {
 648                         wfProfileOut( __METHOD__ );
 649                         return false;
 650                 }
 651
 652                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 653
 654                 // Save to cache for 7 days
 655                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 656                         wfIncrStats( 'diff_uncacheable' );
 657                 } elseif ( $key !== false && $difftext !== false ) {
 658                         wfIncrStats( 'diff_cache_miss' );
 659                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 660                 } else {
 661                         wfIncrStats( 'diff_uncacheable' );
 662                 }
 663                 // Replace line numbers with the text in the user's language
 664                 if ( $difftext !== false ) {
 665                         $difftext = $this->localiseLineNumbers( $difftext );
 666                 }
 667                 wfProfileOut( __METHOD__ );
 668                 return $difftext;
 669         }
 670
 671         /**
 672          * Make sure the proper modules are loaded before we try to
 673          * make the diff
 674          */
 675         private function initDiffEngines() {
 676                 global $wgExternalDiffEngine;
 677                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 678                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 679                         wfDl( 'php_wikidiff' );
 680                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 681                 }
 682                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 683                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 684                         wfDl( 'wikidiff2' );
 685                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 686                 }
 687         }
 688
 689         /**
 690          * Generate a diff, no caching
 691          *
 692          * @param $otext String: old text, must be already segmented
 693          * @param $ntext String: new text, must be already segmented
 694          */
 695         function generateDiffBody( $otext, $ntext ) {
 696                 global $wgExternalDiffEngine, $wgContLang;
 697
 698                 wfProfileIn( __METHOD__ );
 699
 700                 $otext = str_replace( "\r\n", "\n", $otext );
 701                 $ntext = str_replace( "\r\n", "\n", $ntext );
 702
 703                 $this->initDiffEngines();
 704
 705                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 706                         # For historical reasons, external diff engine expects
 707                         # input text to be HTML-escaped already
 708                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 709                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 710                         wfProfileOut( __METHOD__ );
 711                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 712                         $this->debug( 'wikidiff1' );
 713                 }
 714
 715                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 716                         # Better external diff engine, the 2 may some day be dropped
 717                         # This one does the escaping and segmenting itself
 718                         wfProfileIn( 'wikidiff2_do_diff' );
 719                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 720                         $text .= $this->debug( 'wikidiff2' );
 721                         wfProfileOut( 'wikidiff2_do_diff' );
 722                         wfProfileOut( __METHOD__ );
 723                         return $text;
 724                 }
 725                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 726                         # Diff via the shell
 727                         global $wgTmpDirectory;
 728                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 729                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 730
 731                         $tempFile1 = fopen( $tempName1, "w" );
 732                         if ( !$tempFile1 ) {
 733                                 wfProfileOut( __METHOD__ );
 734                                 return false;
 735                         }
 736                         $tempFile2 = fopen( $tempName2, "w" );
 737                         if ( !$tempFile2 ) {
 738                                 wfProfileOut( __METHOD__ );
 739                                 return false;
 740                         }
 741                         fwrite( $tempFile1, $otext );
 742                         fwrite( $tempFile2, $ntext );
 743                         fclose( $tempFile1 );
 744                         fclose( $tempFile2 );
 745                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 746                         wfProfileIn( __METHOD__ . "-shellexec" );
 747                         $difftext = wfShellExec( $cmd );
 748                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 749                         wfProfileOut( __METHOD__ . "-shellexec" );
 750                         unlink( $tempName1 );
 751                         unlink( $tempName2 );
 752                         wfProfileOut( __METHOD__ );
 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                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 762                 wfProfileOut( __METHOD__ );
 763                 return $difftext;
 764         }
 765
 766         /**
 767          * Generate a debug comment indicating diff generating time,
 768          * server node, and generator backend.
 769          */
 770         protected function debug( $generator = "internal" ) {
 771                 global $wgShowHostnames;
 772                 if ( !$this->enableDebugComment ) {
 773                         return '';
 774                 }
 775                 $data = array( $generator );
 776                 if ( $wgShowHostnames ) {
 777                         $data[] = wfHostname();
 778                 }
 779                 $data[] = wfTimestamp( TS_DB );
 780                 return "<!-- diff generator: " .
 781                 implode( " ",
 782                 array_map(
 783                                         "htmlspecialchars",
 784                 $data ) ) .
 785                         " -->\n";
 786         }
 787
 788         /**
 789          * Replace line numbers with the text in the user's language
 790          */
 791         function localiseLineNumbers( $text ) {
 792                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 793                 array( &$this, 'localiseLineNumbersCb' ), $text );
 794         }
 795
 796         function localiseLineNumbersCb( $matches ) {
 797                 global $wgLang;
 798                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 799                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 800         }
 801
 802
 803         /**
 804          * If there are revisions between the ones being compared, return a note saying so.
 805          * @return string
 806          */
 807         function getMultiNotice() {
 808                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 809                         return '';
 810                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 811                         // Comparing two different pages? Count would be meaningless.
 812                         return '';
 813                 }
 814
 815                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 816                         $oldRev = $this->mNewRev; // flip
 817                         $newRev = $this->mOldRev; // flip
 818                 } else { // normal case
 819                         $oldRev = $this->mOldRev;
 820                         $newRev = $this->mNewRev;
 821                 }
 822
 823                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 824                 if ( $nEdits > 0 ) {
 825                         $limit = 100; // use diff-multi-manyusers if too many users
 826                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 827                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 828                 }
 829                 return ''; // nothing
 830         }
 831
 832         /**
 833          * Get a notice about how many intermediate edits and users there are
 834          * @param $numEdits int
 835          * @param $numUsers int
 836          * @param $limit int
 837          * @return string
 838          */
 839         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 840                 global $wgLang;
 841                 if ( $numUsers > $limit ) {
 842                         $msg = 'diff-multi-manyusers';
 843                         $numUsers = $limit;
 844                 } else {
 845                         $msg = 'diff-multi';
 846                 }
 847                 return wfMsgExt( $msg, 'parseinline',
 848                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 849         }
 850
 851         /**
 852          * Get a header for a specified revision.
 853          *
 854          * @param $rev Revision
 855          * @param $complete String: 'complete' to get the header wrapped depending
 856          *        the visibility of the revision and a link to edit the page.
 857          * @return String HTML fragment
 858          */
 859         private function getRevisionHeader( Revision $rev, $complete = '' ) {
 860                 global $wgLang;
 861
 862                 $revtimestamp = $rev->getTimestamp();
 863                 $timestamp = $wgLang->timeanddate( $revtimestamp, true );
 864                 $dateofrev = $wgLang->date( $revtimestamp, true );
 865                 $timeofrev = $wgLang->time( $revtimestamp, true );
 866
 867                 $header = htmlspecialchars( wfMsg(
 868                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 869                         $timestamp,
 870                         $dateofrev,
 871                         $timeofrev
 872                 ) );
 873
 874                 if ( $complete !== 'complete' ) {
 875                         return $header;
 876                 }
 877
 878                 $title = $rev->getTitle();
 879
 880                 $header = Linker::linkKnown( $title, $header, array(),
 881                         array( 'oldid' => $rev->getID() ) );
 882
 883                 if ( $rev->userCan( Revision::DELETED_TEXT ) ) {
 884                         $editQuery = array( 'action' => 'edit' );
 885                         if ( !$rev->isCurrent() ) {
 886                                 $editQuery['oldid'] = $rev->getID();
 887                         }
 888
 889                         $msg = wfMsgHtml( $title->userCan( 'edit' ) ? 'editold' : 'viewsourceold' );
 890                         $header .= ' (' . Linker::linkKnown( $title, $msg, array(), $editQuery ) . ')';
 891                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 892                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 893                         }
 894                 } else {
 895                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 896                 }
 897
 898                 return $header;
 899         }
 900
 901         /**
 902          * Add the header to a diff body
 903          *
 904          * @return string
 905          */
 906         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 907                 // shared.css sets diff in interface language/dir, but the actual content
 908                 // is often in a different language, mostly the page content language/dir
 909                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 910                 $header = "<table class='$tableClass'>";
 911
 912                 if ( !$diff && !$otitle ) {
 913                         $header .= "
 914                         <tr valign='top'>
 915                         <td class='diff-ntitle'>{$ntitle}</td>
 916                         </tr>";
 917                         $multiColspan = 1;
 918                 } else {
 919                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 920                                 $header .= "
 921                                 <col class='diff-marker' />
 922                                 <col class='diff-content' />
 923                                 <col class='diff-marker' />
 924                                 <col class='diff-content' />";
 925                                 $colspan = 2;
 926                                 $multiColspan = 4;
 927                         } else {
 928                                 $colspan = 1;
 929                                 $multiColspan = 2;
 930                         }
 931                         $header .= "
 932                         <tr valign='top'>
 933                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 934                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 935                         </tr>";
 936                 }
 937
 938                 if ( $multi != '' ) {
 939                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 940                 }
 941                 if ( $notice != '' ) {
 942                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 943                 }
 944
 945                 return $header . $diff . "</table>";
 946         }
 947
 948         /**
 949          * Use specified text instead of loading from the database
 950          */
 951         function setText( $oldText, $newText ) {
 952                 $this->mOldtext = $oldText;
 953                 $this->mNewtext = $newText;
 954                 $this->mTextLoaded = 2;
 955                 $this->mRevisionsLoaded = true;
 956         }
 957
 958         /**
 959          * Set the language in which the diff text is written
 960          * (Defaults to page content language).
 961          * @since 1.19
 962          */
 963         function setTextLanguage( $lang ) {
 964                 $this->mDiffLang = wfGetLangObj( $lang );
 965         }
 966
 967         /**
 968          * Load revision IDs
 969          */
 970         private function loadRevisionIds() {
 971                 if ( $this->mRevisionsIdsLoaded ) {
 972                         return;
 973                 }
 974
 975                 $this->mRevisionsIdsLoaded = true;
 976
 977                 $old = $this->mOldid;
 978                 $new = $this->mNewid;
 979
 980                 if ( $new === 'prev' ) {
 981                         # Show diff between revision $old and the previous one.
 982                         # Get previous one from DB.
 983                         $this->mNewid = intval( $old );
 984                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
 985                 } elseif ( $new === 'next' ) {
 986                         # Show diff between revision $old and the next one.
 987                         # Get next one from DB.
 988                         $this->mOldid = intval( $old );
 989                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
 990                         if ( $this->mNewid === false ) {
 991                                 # if no result, NewId points to the newest old revision. The only newer
 992                                 # revision is cur, which is "0".
 993                                 $this->mNewid = 0;
 994                         }
 995                 } else {
 996                         $this->mOldid = intval( $old );
 997                         $this->mNewid = intval( $new );
 998                         wfRunHooks( 'NewDifferenceEngine', array( &$this->mTitle, &$this->mOldid, &$this->mNewid, $old, $new ) );
 999                 }
1000         }
1001
1002         /**
1003          * Load revision metadata for the specified articles. If newid is 0, then compare
1004          * the old article in oldid to the current article; if oldid is 0, then
1005          * compare the current article to the immediately previous one (ignoring the
1006          * value of newid).
1007          *
1008          * If oldid is false, leave the corresponding revision object set
1009          * to false. This is impossible via ordinary user input, and is provided for
1010          * API convenience.
1011          *
1012          * @return bool
1013          */
1014         function loadRevisionData() {
1015                 if ( $this->mRevisionsLoaded ) {
1016                         return true;
1017                 }
1018
1019                 // Whether it succeeds or fails, we don't want to try again
1020                 $this->mRevisionsLoaded = true;
1021
1022                 $this->loadRevisionIds();
1023
1024                 // Load the new revision object
1025                 $this->mNewRev = $this->mNewid
1026                         ? Revision::newFromId( $this->mNewid )
1027                         : Revision::newFromTitle( $this->mTitle );
1028
1029                 if ( !$this->mNewRev instanceof Revision ) {
1030                         return false;
1031                 }
1032
1033                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1034                 $this->mNewid = $this->mNewRev->getId();
1035                 $this->mNewPage = $this->mNewRev->getTitle();
1036
1037                 // Load the old revision object
1038                 $this->mOldRev = false;
1039                 if ( $this->mOldid ) {
1040                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1041                 } elseif ( $this->mOldid === 0 ) {
1042                         $rev = $this->mNewRev->getPrevious();
1043                         if ( $rev ) {
1044                                 $this->mOldid = $rev->getId();
1045                                 $this->mOldRev = $rev;
1046                         } else {
1047                                 // No previous revision; mark to show as first-version only.
1048                                 $this->mOldid = false;
1049                                 $this->mOldRev = false;
1050                         }
1051                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1052
1053                 if ( is_null( $this->mOldRev ) ) {
1054                         return false;
1055                 }
1056
1057                 if ( $this->mOldRev ) {
1058                         $this->mOldPage = $this->mOldRev->getTitle();
1059                 }
1060
1061                 return true;
1062         }
1063
1064         /**
1065          * Load the text of the revisions, as well as revision data.
1066          *
1067          * @return bool
1068          */
1069         function loadText() {
1070                 if ( $this->mTextLoaded == 2 ) {
1071                         return true;
1072                 } else {
1073                         // Whether it succeeds or fails, we don't want to try again
1074                         $this->mTextLoaded = 2;
1075                 }
1076
1077                 if ( !$this->loadRevisionData() ) {
1078                         return false;
1079                 }
1080                 if ( $this->mOldRev ) {
1081                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1082                         if ( $this->mOldtext === false ) {
1083                                 return false;
1084                         }
1085                 }
1086                 if ( $this->mNewRev ) {
1087                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1088                         if ( $this->mNewtext === false ) {
1089                                 return false;
1090                         }
1091                 }
1092                 return true;
1093         }
1094
1095         /**
1096          * Load the text of the new revision, not the old one
1097          *
1098          * @return bool
1099          */
1100         function loadNewText() {
1101                 if ( $this->mTextLoaded >= 1 ) {
1102                         return true;
1103                 } else {
1104                         $this->mTextLoaded = 1;
1105                 }
1106                 if ( !$this->loadRevisionData() ) {
1107                         return false;
1108                 }
1109                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1110                 return true;
1111         }
1112 }