includes/diff/DifferenceInterface.php

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