includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup DifferenceEngine
  22  */
  23
  24 /**
  25  * Constant to indicate diff cache compatibility.
  26  * Bump this when changing the diff formatting in a way that
  27  * fixes important bugs or such to force cached diff views to
  28  * clear.
  29  */
  30 define( 'MW_DIFF_VERSION', '1.11a' );
  31
  32 /**
  33  * @todo document
  34  * @ingroup DifferenceEngine
  35  */
  36 class DifferenceEngine extends ContextSource {
  37         /**#@+
  38          * @private
  39          */
  40         var $mOldid, $mNewid;
  41         var $mOldtext, $mNewtext;
  42         protected $mDiffLang;
  43
  44         /**
  45          * @var Title
  46          */
  47         var $mOldPage, $mNewPage;
  48         var $mRcidMarkPatrolled;
  49
  50         /**
  51          * @var Revision
  52          */
  53         var $mOldRev, $mNewRev;
  54         private $mRevisionsIdsLoaded = false; // Have the revisions IDs been loaded
  55         var $mRevisionsLoaded = false; // Have the revisions been loaded
  56         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  57         var $mCacheHit = false; // Was the diff fetched from cache?
  58
  59         /**
  60          * Set this to true to add debug info to the HTML output.
  61          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  62          * (bug 20601)
  63          */
  64         var $enableDebugComment = false;
  65
  66         // If true, line X is not displayed when X is 1, for example to increase
  67         // readability and conserve space with many small diffs.
  68         protected $mReducedLineNumbers = false;
  69
  70         // Link to action=markpatrolled
  71         protected $mMarkPatrolledLink = null;
  72
  73         protected $unhide = false; # show rev_deleted content if allowed
  74         /**#@-*/
  75
  76         /**
  77          * Constructor
  78          * @param $context IContextSource context to use, anything else will be ignored
  79          * @param $old Integer old ID we want to show and diff with.
  80          * @param $new String either 'prev' or 'next'.
  81          * @param $rcid Integer ??? FIXME (default 0)
  82          * @param $refreshCache boolean If set, refreshes the diff cache
  83          * @param $unhide boolean If set, allow viewing deleted revs
  84          */
  85         function __construct( $context = null, $old = 0, $new = 0, $rcid = 0,
  86                 $refreshCache = false, $unhide = false )
  87         {
  88                 if ( $context instanceof IContextSource ) {
  89                         $this->setContext( $context );
  90                 }
  91
  92                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  93
  94                 $this->mOldid = $old;
  95                 $this->mNewid = $new;
  96                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  97                 $this->mRefreshCache = $refreshCache;
  98                 $this->unhide = $unhide;
  99         }
 100
 101         /**
 102          * @param $value bool
 103          */
 104         function setReducedLineNumbers( $value = true ) {
 105                 $this->mReducedLineNumbers = $value;
 106         }
 107
 108         /**
 109          * @return Language
 110          */
 111         function getDiffLang() {
 112                 if ( $this->mDiffLang === null ) {
 113                         # Default language in which the diff text is written.
 114                         $this->mDiffLang = $this->getTitle()->getPageLanguage();
 115                 }
 116                 return $this->mDiffLang;
 117         }
 118
 119         /**
 120          * @return bool
 121          */
 122         function wasCacheHit() {
 123                 return $this->mCacheHit;
 124         }
 125
 126         /**
 127          * @return int
 128          */
 129         function getOldid() {
 130                 $this->loadRevisionIds();
 131                 return $this->mOldid;
 132         }
 133
 134         /**
 135          * @return Bool|int
 136          */
 137         function getNewid() {
 138                 $this->loadRevisionIds();
 139                 return $this->mNewid;
 140         }
 141
 142         /**
 143          * Look up a special:Undelete link to the given deleted revision id,
 144          * as a workaround for being unable to load deleted diffs in currently.
 145          *
 146          * @param int $id revision ID
 147          * @return mixed URL or false
 148          */
 149         function deletedLink( $id ) {
 150                 if ( $this->getUser()->isAllowed( 'deletedhistory' ) ) {
 151                         $dbr = wfGetDB( DB_SLAVE );
 152                         $row = $dbr->selectRow('archive', '*',
 153                                 array( 'ar_rev_id' => $id ),
 154                                 __METHOD__ );
 155                         if ( $row ) {
 156                                 $rev = Revision::newFromArchiveRow( $row );
 157                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 158                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 159                                         'target' => $title->getPrefixedText(),
 160                                         'timestamp' => $rev->getTimestamp()
 161                                 ));
 162                         }
 163                 }
 164                 return false;
 165         }
 166
 167         /**
 168          * Build a wikitext link toward a deleted revision, if viewable.
 169          *
 170          * @param int $id revision ID
 171          * @return string wikitext fragment
 172          */
 173         function deletedIdMarker( $id ) {
 174                 $link = $this->deletedLink( $id );
 175                 if ( $link ) {
 176                         return "[$link $id]";
 177                 } else {
 178                         return $id;
 179                 }
 180         }
 181
 182         function showDiffPage( $diffOnly = false ) {
 183                 wfProfileIn( __METHOD__ );
 184
 185                 # Allow frames except in certain special cases
 186                 $out = $this->getOutput();
 187                 $out->allowClickjacking();
 188                 $out->setRobotPolicy( 'noindex,nofollow' );
 189
 190                 if ( !$this->loadRevisionData() ) {
 191                         // Sounds like a deleted revision... Let's see what we can do.
 192                         $t = $this->getTitle()->getPrefixedText();
 193                         $d = $this->msg( 'missingarticle-diff',
 194                                 $this->deletedIdMarker( $this->mOldid ),
 195                                 $this->deletedIdMarker( $this->mNewid ) )->escaped();
 196                         $out->setPageTitle( $this->msg( 'errorpagetitle' ) );
 197                         $out->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 198                         wfProfileOut( __METHOD__ );
 199                         return;
 200                 }
 201
 202                 $user = $this->getUser();
 203                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $user );
 204                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 205                         $permErrors = wfMergeErrorArrays( $permErrors,
 206                                 $this->mOldPage->getUserPermissionsErrors( 'read', $user ) );
 207                 }
 208                 if ( count( $permErrors ) ) {
 209                         wfProfileOut( __METHOD__ );
 210                         throw new PermissionsError( 'read', $permErrors );
 211                 }
 212
 213                 # If external diffs are enabled both globally and for the user,
 214                 # we'll use the application/x-external-editor interface to call
 215                 # an external diff tool like kompare, kdiff3, etc.
 216                 if ( ExternalEdit::useExternalEngine( $this->getContext(), 'diff' ) ) {
 217                         $urls = array(
 218                                 'File' => array( 'Extension' => 'wiki', 'URL' =>
 219                                         # This should be mOldPage, but it may not be set, see below.
 220                                         $this->mNewPage->getCanonicalURL( array(
 221                                                 'action' => 'raw', 'oldid' => $this->mOldid ) )
 222                                 ),
 223                                 'File2' => array( 'Extension' => 'wiki', 'URL' =>
 224                                         $this->mNewPage->getCanonicalURL( array(
 225                                                 'action' => 'raw', 'oldid' => $this->mNewid ) )
 226                                 ),
 227                         );
 228
 229                         $externalEditor = new ExternalEdit( $this->getContext(), $urls );
 230                         $externalEditor->execute();
 231
 232                         wfProfileOut( __METHOD__ );
 233                         return;
 234                 }
 235
 236                 $rollback = '';
 237                 $undoLink = '';
 238
 239                 $query = array();
 240                 # Carry over 'diffonly' param via navigation links
 241                 if ( $diffOnly != $user->getBoolOption( 'diffonly' ) ) {
 242                         $query['diffonly'] = $diffOnly;
 243                 }
 244                 # Cascade unhide param in links for easy deletion browsing
 245                 if ( $this->unhide ) {
 246                         $query['unhide'] = 1;
 247                 }
 248
 249                 # Check if one of the revisions is deleted/suppressed
 250                 $deleted = $suppressed = false;
 251                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT, $user );
 252
 253                 # mOldRev is false if the difference engine is called with a "vague" query for
 254                 # a diff between a version V and its previous version V' AND the version V
 255                 # is the first version of that article. In that case, V' does not exist.
 256                 if ( $this->mOldRev === false ) {
 257                         $out->setPageTitle( $this->mNewPage->getPrefixedText() );
 258                         $out->addSubtitle( $this->msg( 'difference' ) );
 259                         $samePage = true;
 260                         $oldHeader = '';
 261                 } else {
 262                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 263
 264                         $sk = $this->getSkin();
 265                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 266                                 $sk->suppressQuickbar();
 267                         }
 268
 269                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 270                                 $out->setPageTitle( $this->mNewPage->getPrefixedText() );
 271                                 $out->addSubtitle( $this->msg( 'difference' ) );
 272                                 $samePage = true;
 273                         } else {
 274                                 $out->setPageTitle( $this->mOldPage->getPrefixedText() . ', ' . $this->mNewPage->getPrefixedText() );
 275                                 $out->addSubtitle( $this->msg( 'difference-multipage' ) );
 276                                 $samePage = false;
 277                         }
 278
 279                         if ( $samePage && $this->mNewPage->quickUserCan( 'edit', $user ) ) {
 280                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback', $user ) ) {
 281                                         $out->preventClickjacking();
 282                                         $rollback = '&#160;&#160;&#160;' . Linker::generateRollback( $this->mNewRev );
 283                                 }
 284                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 285                                         $undoLink = ' ' . $this->msg( 'parentheses' )->rawParams(
 286                                                 Html::element( 'a', array(
 287                                                         'href' => $this->mNewPage->getLocalUrl( array(
 288                                                                 'action' => 'edit',
 289                                                                 'undoafter' => $this->mOldid,
 290                                                                 'undo' => $this->mNewid ) ),
 291                                                         'title' => Linker::titleAttrib( 'undo' )
 292                                                 ),
 293                                                 $this->msg( 'editundo' )->text()
 294                                         ) )->escaped();
 295                                 }
 296                         }
 297
 298                         # Make "previous revision link"
 299                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 300                                 $prevlink = Linker::linkKnown(
 301                                         $this->mOldPage,
 302                                         $this->msg( 'previousdiff' )->escaped(),
 303                                         array( 'id' => 'differences-prevlink' ),
 304                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 305                                 );
 306                         } else {
 307                                 $prevlink = '&#160;';
 308                         }
 309
 310                         if ( $this->mOldRev->isMinor() ) {
 311                                 $oldminor = ChangesList::flag( 'minor' );
 312                         } else {
 313                                 $oldminor = '';
 314                         }
 315
 316                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 317                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 318
 319                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 320                                 '<div id="mw-diff-otitle2">' .
 321                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 322                                 '<div id="mw-diff-otitle3">' . $oldminor .
 323                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 324                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 325
 326                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 327                                 $deleted = true; // old revisions text is hidden
 328                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 329                                         $suppressed = true; // also suppressed
 330                                 }
 331                         }
 332
 333                         # Check if this user can see the revisions
 334                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT, $user ) ) {
 335                                 $allowed = false;
 336                         }
 337                 }
 338
 339                 # Make "next revision link"
 340                 # Skip next link on the top revision
 341                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 342                         $nextlink = Linker::linkKnown(
 343                                 $this->mNewPage,
 344                                 $this->msg( 'nextdiff' )->escaped(),
 345                                 array( 'id' => 'differences-nextlink' ),
 346                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 347                         );
 348                 } else {
 349                         $nextlink = '&#160;';
 350                 }
 351
 352                 if ( $this->mNewRev->isMinor() ) {
 353                         $newminor = ChangesList::flag( 'minor' );
 354                 } else {
 355                         $newminor = '';
 356                 }
 357
 358                 # Handle RevisionDelete links...
 359                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 360                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 361
 362                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 363                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 364                                 " $rollback</div>" .
 365                         '<div id="mw-diff-ntitle3">' . $newminor .
 366                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 367                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 368
 369                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 370                         $deleted = true; // new revisions text is hidden
 371                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 372                                 $suppressed = true; // also suppressed
 373                 }
 374
 375                 # If the diff cannot be shown due to a deleted revision, then output
 376                 # the diff header and links to unhide (if available)...
 377                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 378                         $this->showDiffStyle();
 379                         $multi = $this->getMultiNotice();
 380                         $out->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 381                         if ( !$allowed ) {
 382                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 383                                 # Give explanation for why revision is not visible
 384                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 385                                         array( $msg ) );
 386                         } else {
 387                                 # Give explanation and add a link to view the diff...
 388                                 $link = $this->getTitle()->getFullUrl( $this->getRequest()->appendQueryValue( 'unhide', '1', true ) );
 389                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 390                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 391                         }
 392                 # Otherwise, output a regular diff...
 393                 } else {
 394                         # Add deletion notice if the user is viewing deleted content
 395                         $notice = '';
 396                         if ( $deleted ) {
 397                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 398                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . $this->msg( $msg )->parse() . "</div>\n";
 399                         }
 400                         $this->showDiff( $oldHeader, $newHeader, $notice );
 401                         if ( !$diffOnly ) {
 402                                 $this->renderNewRevision();
 403                         }
 404                 }
 405                 wfProfileOut( __METHOD__ );
 406         }
 407
 408         /**
 409          * Get a link to mark the change as patrolled, or '' if there's either no
 410          * revision to patrol or the user is not allowed to to it.
 411          * Side effect: this method will call OutputPage::preventClickjacking()
 412          * when a link is builded.
 413          *
 414          * @return String
 415          */
 416         protected function markPatrolledLink() {
 417                 global $wgUseRCPatrol;
 418
 419                 if ( $this->mMarkPatrolledLink === null ) {
 420                         // Prepare a change patrol link, if applicable
 421                         if ( $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) ) {
 422                                 // If we've been given an explicit change identifier, use it; saves time
 423                                 if ( $this->mRcidMarkPatrolled ) {
 424                                         $rcid = $this->mRcidMarkPatrolled;
 425                                         $rc = RecentChange::newFromId( $rcid );
 426                                         // Already patrolled?
 427                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 428                                 } else {
 429                                         // Look for an unpatrolled change corresponding to this diff
 430                                         $db = wfGetDB( DB_SLAVE );
 431                                         $change = RecentChange::newFromConds(
 432                                                 array(
 433                                                 // Redundant user,timestamp condition so we can use the existing index
 434                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 435                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 436                                                         'rc_this_oldid' => $this->mNewid,
 437                                                         'rc_last_oldid' => $this->mOldid,
 438                                                         'rc_patrolled'  => 0
 439                                                 ),
 440                                                 __METHOD__
 441                                         );
 442                                         if ( $change instanceof RecentChange ) {
 443                                                 $rcid = $change->mAttribs['rc_id'];
 444                                                 $this->mRcidMarkPatrolled = $rcid;
 445                                         } else {
 446                                                 // None found
 447                                                 $rcid = 0;
 448                                         }
 449                                 }
 450                                 // Build the link
 451                                 if ( $rcid ) {
 452                                         $this->getOutput()->preventClickjacking();
 453                                         $token = $this->getUser()->getEditToken( $rcid );
 454                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 455                                                 $this->mNewPage,
 456                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 457                                                 array(),
 458                                                 array(
 459                                                         'action' => 'markpatrolled',
 460                                                         'rcid' => $rcid,
 461                                                         'token' => $token,
 462                                                 )
 463                                         ) . ']</span>';
 464                                 } else {
 465                                         $this->mMarkPatrolledLink = '';
 466                                 }
 467                         } else {
 468                                 $this->mMarkPatrolledLink = '';
 469                         }
 470                 }
 471
 472                 return $this->mMarkPatrolledLink;
 473         }
 474
 475         /**
 476          * @param $rev Revision
 477          * @return String
 478          */
 479         protected function revisionDeleteLink( $rev ) {
 480                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 481                 if ( $link !== '' ) {
 482                         $link = '&#160;&#160;&#160;' . $link . ' ';
 483                 }
 484                 return $link;
 485         }
 486
 487         /**
 488          * Show the new revision of the page.
 489          */
 490         function renderNewRevision() {
 491                 wfProfileIn( __METHOD__ );
 492                 $out = $this->getOutput();
 493                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 494                 # Add "current version as of X" title
 495                 $out->addHTML( "<hr class='diff-hr' />
 496                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 497                 # Page content may be handled by a hooked call instead...
 498                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 499                         $this->loadNewText();
 500                         $out->setRevisionId( $this->mNewid );
 501                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 502                         $out->setArticleFlag( true );
 503
 504                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 505                                 // Stolen from Article::view --AG 2007-10-11
 506                                 // Give hooks a chance to customise the output
 507                                 // @TODO: standardize this crap into one function
 508                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mNewPage, $out ) ) ) {
 509                                         // Wrap the whole lot in a <pre> and don't parse
 510                                         $m = array();
 511                                         preg_match( '!\.(css|js)$!u', $this->mNewPage->getText(), $m );
 512                                         $out->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 513                                         $out->addHTML( htmlspecialchars( $this->mNewtext ) );
 514                                         $out->addHTML( "\n</pre>\n" );
 515                                 }
 516                         } elseif ( !wfRunHooks( 'ArticleViewCustom', array( $this->mNewtext, $this->mNewPage, $out ) ) ) {
 517                                 // Handled by extension
 518                         } else {
 519                                 // Normal page
 520                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 521                                         // If the Title stored in the context is the same as the one
 522                                         // of the new revision, we can use its associated WikiPage
 523                                         // object.
 524                                         $wikiPage = $this->getWikiPage();
 525                                 } else {
 526                                         // Otherwise we need to create our own WikiPage object
 527                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 528                                 }
 529
 530                                 $parserOptions = ParserOptions::newFromContext( $this->getContext() );
 531                                 $parserOptions->enableLimitReport();
 532                                 $parserOptions->setTidy( true );
 533
 534                                 if ( !$this->mNewRev->isCurrent() ) {
 535                                         $parserOptions->setEditSection( false );
 536                                 }
 537
 538                                 $parserOutput = $wikiPage->getParserOutput( $parserOptions, $this->mNewid );
 539
 540                                 # WikiPage::getParserOutput() should not return false, but just in case
 541                                 if( $parserOutput ) {
 542                                         $out->addParserOutput( $parserOutput );
 543                                 }
 544                         }
 545                 }
 546                 # Add redundant patrol link on bottom...
 547                 $out->addHTML( $this->markPatrolledLink() );
 548
 549                 wfProfileOut( __METHOD__ );
 550         }
 551
 552         /**
 553          * Get the diff text, send it to the OutputPage object
 554          * Returns false if the diff could not be generated, otherwise returns true
 555          *
 556          * @return bool
 557          */
 558         function showDiff( $otitle, $ntitle, $notice = '' ) {
 559                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 560                 if ( $diff === false ) {
 561                         $this->getOutput()->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 562                         return false;
 563                 } else {
 564                         $this->showDiffStyle();
 565                         $this->getOutput()->addHTML( $diff );
 566                         return true;
 567                 }
 568         }
 569
 570         /**
 571          * Add style sheets and supporting JS for diff display.
 572          */
 573         function showDiffStyle() {
 574                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 575         }
 576
 577         /**
 578          * Get complete diff table, including header
 579          *
 580          * @param $otitle Title: old title
 581          * @param $ntitle Title: new title
 582          * @param $notice String: HTML between diff header and body
 583          * @return mixed
 584          */
 585         function getDiff( $otitle, $ntitle, $notice = '' ) {
 586                 $body = $this->getDiffBody();
 587                 if ( $body === false ) {
 588                         return false;
 589                 } else {
 590                         $multi = $this->getMultiNotice();
 591                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 592                 }
 593         }
 594
 595         /**
 596          * Get the diff table body, without header
 597          *
 598          * @return mixed (string/false)
 599          */
 600         public function getDiffBody() {
 601                 global $wgMemc;
 602                 wfProfileIn( __METHOD__ );
 603                 $this->mCacheHit = true;
 604                 // Check if the diff should be hidden from this user
 605                 if ( !$this->loadRevisionData() ) {
 606                         wfProfileOut( __METHOD__ );
 607                         return false;
 608                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 609                         wfProfileOut( __METHOD__ );
 610                         return false;
 611                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 612                         wfProfileOut( __METHOD__ );
 613                         return false;
 614                 }
 615                 // Short-circuit
 616                 // If mOldRev is false, it means that the
 617                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 618                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 619                 {
 620                         wfProfileOut( __METHOD__ );
 621                         return '';
 622                 }
 623                 // Cacheable?
 624                 $key = false;
 625                 if ( $this->mOldid && $this->mNewid ) {
 626                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 627                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 628                         // Try cache
 629                         if ( !$this->mRefreshCache ) {
 630                                 $difftext = $wgMemc->get( $key );
 631                                 if ( $difftext ) {
 632                                         wfIncrStats( 'diff_cache_hit' );
 633                                         $difftext = $this->localiseLineNumbers( $difftext );
 634                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 635                                         wfProfileOut( __METHOD__ );
 636                                         return $difftext;
 637                                 }
 638                         } // don't try to load but save the result
 639                 }
 640                 $this->mCacheHit = false;
 641
 642                 // Loadtext is permission safe, this just clears out the diff
 643                 if ( !$this->loadText() ) {
 644                         wfProfileOut( __METHOD__ );
 645                         return false;
 646                 }
 647
 648                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 649
 650                 // Save to cache for 7 days
 651                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 652                         wfIncrStats( 'diff_uncacheable' );
 653                 } elseif ( $key !== false && $difftext !== false ) {
 654                         wfIncrStats( 'diff_cache_miss' );
 655                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 656                 } else {
 657                         wfIncrStats( 'diff_uncacheable' );
 658                 }
 659                 // Replace line numbers with the text in the user's language
 660                 if ( $difftext !== false ) {
 661                         $difftext = $this->localiseLineNumbers( $difftext );
 662                 }
 663                 wfProfileOut( __METHOD__ );
 664                 return $difftext;
 665         }
 666
 667         /**
 668          * Make sure the proper modules are loaded before we try to
 669          * make the diff
 670          */
 671         private function initDiffEngines() {
 672                 global $wgExternalDiffEngine;
 673                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 674                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 675                         wfDl( 'php_wikidiff' );
 676                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 677                 }
 678                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 679                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 680                         wfDl( 'wikidiff2' );
 681                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 682                 }
 683         }
 684
 685         /**
 686          * Generate a diff, no caching
 687          *
 688          * @param $otext String: old text, must be already segmented
 689          * @param $ntext String: new text, must be already segmented
 690          * @return bool|string
 691          */
 692         function generateDiffBody( $otext, $ntext ) {
 693                 global $wgExternalDiffEngine, $wgContLang;
 694
 695                 wfProfileIn( __METHOD__ );
 696
 697                 $otext = str_replace( "\r\n", "\n", $otext );
 698                 $ntext = str_replace( "\r\n", "\n", $ntext );
 699
 700                 $this->initDiffEngines();
 701
 702                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 703                         # For historical reasons, external diff engine expects
 704                         # input text to be HTML-escaped already
 705                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 706                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 707                         wfProfileOut( __METHOD__ );
 708                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 709                         $this->debug( 'wikidiff1' );
 710                 }
 711
 712                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 713                         # Better external diff engine, the 2 may some day be dropped
 714                         # This one does the escaping and segmenting itself
 715                         wfProfileIn( 'wikidiff2_do_diff' );
 716                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 717                         $text .= $this->debug( 'wikidiff2' );
 718                         wfProfileOut( 'wikidiff2_do_diff' );
 719                         wfProfileOut( __METHOD__ );
 720                         return $text;
 721                 }
 722                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 723                         # Diff via the shell
 724                         global $wgTmpDirectory;
 725                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 726                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 727
 728                         $tempFile1 = fopen( $tempName1, "w" );
 729                         if ( !$tempFile1 ) {
 730                                 wfProfileOut( __METHOD__ );
 731                                 return false;
 732                         }
 733                         $tempFile2 = fopen( $tempName2, "w" );
 734                         if ( !$tempFile2 ) {
 735                                 wfProfileOut( __METHOD__ );
 736                                 return false;
 737                         }
 738                         fwrite( $tempFile1, $otext );
 739                         fwrite( $tempFile2, $ntext );
 740                         fclose( $tempFile1 );
 741                         fclose( $tempFile2 );
 742                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 743                         wfProfileIn( __METHOD__ . "-shellexec" );
 744                         $difftext = wfShellExec( $cmd );
 745                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 746                         wfProfileOut( __METHOD__ . "-shellexec" );
 747                         unlink( $tempName1 );
 748                         unlink( $tempName2 );
 749                         wfProfileOut( __METHOD__ );
 750                         return $difftext;
 751                 }
 752
 753                 # Native PHP diff
 754                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 755                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 756                 $diffs = new Diff( $ota, $nta );
 757                 $formatter = new TableDiffFormatter();
 758                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 759                 wfProfileOut( __METHOD__ );
 760                 return $difftext;
 761         }
 762
 763         /**
 764          * Generate a debug comment indicating diff generating time,
 765          * server node, and generator backend.
 766          * @return string
 767          */
 768         protected function debug( $generator = "internal" ) {
 769                 global $wgShowHostnames;
 770                 if ( !$this->enableDebugComment ) {
 771                         return '';
 772                 }
 773                 $data = array( $generator );
 774                 if ( $wgShowHostnames ) {
 775                         $data[] = wfHostname();
 776                 }
 777                 $data[] = wfTimestamp( TS_DB );
 778                 return "<!-- diff generator: " .
 779                 implode( " ",
 780                 array_map(
 781                                         "htmlspecialchars",
 782                 $data ) ) .
 783                         " -->\n";
 784         }
 785
 786         /**
 787          * Replace line numbers with the text in the user's language
 788          * @return mixed
 789          */
 790         function localiseLineNumbers( $text ) {
 791                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 792                 array( &$this, 'localiseLineNumbersCb' ), $text );
 793         }
 794
 795         function localiseLineNumbersCb( $matches ) {
 796                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 797                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 798         }
 799
 800
 801         /**
 802          * If there are revisions between the ones being compared, return a note saying so.
 803          * @return string
 804          */
 805         function getMultiNotice() {
 806                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 807                         return '';
 808                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 809                         // Comparing two different pages? Count would be meaningless.
 810                         return '';
 811                 }
 812
 813                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 814                         $oldRev = $this->mNewRev; // flip
 815                         $newRev = $this->mOldRev; // flip
 816                 } else { // normal case
 817                         $oldRev = $this->mOldRev;
 818                         $newRev = $this->mNewRev;
 819                 }
 820
 821                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 822                 if ( $nEdits > 0 ) {
 823                         $limit = 100; // use diff-multi-manyusers if too many users
 824                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 825                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 826                 }
 827                 return ''; // nothing
 828         }
 829
 830         /**
 831          * Get a notice about how many intermediate edits and users there are
 832          * @param $numEdits int
 833          * @param $numUsers int
 834          * @param $limit int
 835          * @return string
 836          */
 837         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 838                 if ( $numUsers > $limit ) {
 839                         $msg = 'diff-multi-manyusers';
 840                         $numUsers = $limit;
 841                 } else {
 842                         $msg = 'diff-multi';
 843                 }
 844                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 845         }
 846
 847         /**
 848          * Get a header for a specified revision.
 849          *
 850          * @param $rev Revision
 851          * @param $complete String: 'complete' to get the header wrapped depending
 852          *        the visibility of the revision and a link to edit the page.
 853          * @return String HTML fragment
 854          */
 855         private function getRevisionHeader( Revision $rev, $complete = '' ) {
 856                 $lang = $this->getLanguage();
 857                 $user = $this->getUser();
 858                 $revtimestamp = $rev->getTimestamp();
 859                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 860                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 861                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 862
 863                 $header = $this->msg(
 864                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 865                         $timestamp,
 866                         $dateofrev,
 867                         $timeofrev
 868                 )->escaped();
 869
 870                 if ( $complete !== 'complete' ) {
 871                         return $header;
 872                 }
 873
 874                 $title = $rev->getTitle();
 875
 876                 $header = Linker::linkKnown( $title, $header, array(),
 877                         array( 'oldid' => $rev->getID() ) );
 878
 879                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 880                         $editQuery = array( 'action' => 'edit' );
 881                         if ( !$rev->isCurrent() ) {
 882                                 $editQuery['oldid'] = $rev->getID();
 883                         }
 884
 885                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 886                         $header .= ' (' . Linker::linkKnown( $title, $msg, array(), $editQuery ) . ')';
 887                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 888                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 889                         }
 890                 } else {
 891                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 892                 }
 893
 894                 return $header;
 895         }
 896
 897         /**
 898          * Add the header to a diff body
 899          *
 900          * @return string
 901          */
 902         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 903                 // shared.css sets diff in interface language/dir, but the actual content
 904                 // is often in a different language, mostly the page content language/dir
 905                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 906                 $header = "<table class='$tableClass'>";
 907
 908                 if ( !$diff && !$otitle ) {
 909                         $header .= "
 910                         <tr valign='top'>
 911                         <td class='diff-ntitle'>{$ntitle}</td>
 912                         </tr>";
 913                         $multiColspan = 1;
 914                 } else {
 915                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 916                                 $header .= "
 917                                 <col class='diff-marker' />
 918                                 <col class='diff-content' />
 919                                 <col class='diff-marker' />
 920                                 <col class='diff-content' />";
 921                                 $colspan = 2;
 922                                 $multiColspan = 4;
 923                         } else {
 924                                 $colspan = 1;
 925                                 $multiColspan = 2;
 926                         }
 927                         $header .= "
 928                         <tr valign='top'>
 929                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 930                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 931                         </tr>";
 932                 }
 933
 934                 if ( $multi != '' ) {
 935                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 936                 }
 937                 if ( $notice != '' ) {
 938                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 939                 }
 940
 941                 return $header . $diff . "</table>";
 942         }
 943
 944         /**
 945          * Use specified text instead of loading from the database
 946          */
 947         function setText( $oldText, $newText ) {
 948                 $this->mOldtext = $oldText;
 949                 $this->mNewtext = $newText;
 950                 $this->mTextLoaded = 2;
 951                 $this->mRevisionsLoaded = true;
 952         }
 953
 954         /**
 955          * Set the language in which the diff text is written
 956          * (Defaults to page content language).
 957          * @since 1.19
 958          */
 959         function setTextLanguage( $lang ) {
 960                 $this->mDiffLang = wfGetLangObj( $lang );
 961         }
 962
 963         /**
 964          * Load revision IDs
 965          */
 966         private function loadRevisionIds() {
 967                 if ( $this->mRevisionsIdsLoaded ) {
 968                         return;
 969                 }
 970
 971                 $this->mRevisionsIdsLoaded = true;
 972
 973                 $old = $this->mOldid;
 974                 $new = $this->mNewid;
 975
 976                 if ( $new === 'prev' ) {
 977                         # Show diff between revision $old and the previous one.
 978                         # Get previous one from DB.
 979                         $this->mNewid = intval( $old );
 980                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
 981                 } elseif ( $new === 'next' ) {
 982                         # Show diff between revision $old and the next one.
 983                         # Get next one from DB.
 984                         $this->mOldid = intval( $old );
 985                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
 986                         if ( $this->mNewid === false ) {
 987                                 # if no result, NewId points to the newest old revision. The only newer
 988                                 # revision is cur, which is "0".
 989                                 $this->mNewid = 0;
 990                         }
 991                 } else {
 992                         $this->mOldid = intval( $old );
 993                         $this->mNewid = intval( $new );
 994                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
 995                 }
 996         }
 997
 998         /**
 999          * Load revision metadata for the specified articles. If newid is 0, then compare
1000          * the old article in oldid to the current article; if oldid is 0, then
1001          * compare the current article to the immediately previous one (ignoring the
1002          * value of newid).
1003          *
1004          * If oldid is false, leave the corresponding revision object set
1005          * to false. This is impossible via ordinary user input, and is provided for
1006          * API convenience.
1007          *
1008          * @return bool
1009          */
1010         function loadRevisionData() {
1011                 if ( $this->mRevisionsLoaded ) {
1012                         return true;
1013                 }
1014
1015                 // Whether it succeeds or fails, we don't want to try again
1016                 $this->mRevisionsLoaded = true;
1017
1018                 $this->loadRevisionIds();
1019
1020                 // Load the new revision object
1021                 $this->mNewRev = $this->mNewid
1022                         ? Revision::newFromId( $this->mNewid )
1023                         : Revision::newFromTitle( $this->getTitle() );
1024
1025                 if ( !$this->mNewRev instanceof Revision ) {
1026                         return false;
1027                 }
1028
1029                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1030                 $this->mNewid = $this->mNewRev->getId();
1031                 $this->mNewPage = $this->mNewRev->getTitle();
1032
1033                 // Load the old revision object
1034                 $this->mOldRev = false;
1035                 if ( $this->mOldid ) {
1036                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1037                 } elseif ( $this->mOldid === 0 ) {
1038                         $rev = $this->mNewRev->getPrevious();
1039                         if ( $rev ) {
1040                                 $this->mOldid = $rev->getId();
1041                                 $this->mOldRev = $rev;
1042                         } else {
1043                                 // No previous revision; mark to show as first-version only.
1044                                 $this->mOldid = false;
1045                                 $this->mOldRev = false;
1046                         }
1047                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1048
1049                 if ( is_null( $this->mOldRev ) ) {
1050                         return false;
1051                 }
1052
1053                 if ( $this->mOldRev ) {
1054                         $this->mOldPage = $this->mOldRev->getTitle();
1055                 }
1056
1057                 return true;
1058         }
1059
1060         /**
1061          * Load the text of the revisions, as well as revision data.
1062          *
1063          * @return bool
1064          */
1065         function loadText() {
1066                 if ( $this->mTextLoaded == 2 ) {
1067                         return true;
1068                 } else {
1069                         // Whether it succeeds or fails, we don't want to try again
1070                         $this->mTextLoaded = 2;
1071                 }
1072
1073                 if ( !$this->loadRevisionData() ) {
1074                         return false;
1075                 }
1076                 if ( $this->mOldRev ) {
1077                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1078                         if ( $this->mOldtext === false ) {
1079                                 return false;
1080                         }
1081                 }
1082                 if ( $this->mNewRev ) {
1083                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1084                         if ( $this->mNewtext === false ) {
1085                                 return false;
1086                         }
1087                 }
1088                 return true;
1089         }
1090
1091         /**
1092          * Load the text of the new revision, not the old one
1093          *
1094          * @return bool
1095          */
1096         function loadNewText() {
1097                 if ( $this->mTextLoaded >= 1 ) {
1098                         return true;
1099                 } else {
1100                         $this->mTextLoaded = 1;
1101                 }
1102                 if ( !$this->loadRevisionData() ) {
1103                         return false;
1104                 }
1105                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1106                 return true;
1107         }
1108 }