includes/diff/DifferenceEngine.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         var $htmldiff;
  32
  33         protected $unhide = false;
  34         /**#@-*/
  35
  36         /**
  37          * Constructor
  38          * @param $titleObj Title object that the diff is associated with
  39          * @param $old Integer: old ID we want to show and diff with.
  40          * @param $new String: either 'prev' or 'next'.
  41          * @param $rcid Integer: ??? FIXME (default 0)
  42          * @param $refreshCache boolean If set, refreshes the diff cache
  43          * @param $htmldiff boolean If set, output using HTMLDiff instead of raw wikicode diff
  44          * @param $unhide boolean If set, allow viewing deleted revs
  45          */
  46         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  47                 $refreshCache = false, $htmldiff = false, $unhide = false )
  48         {
  49                 if ( $titleObj ) {
  50                         $this->mTitle = $titleObj;
  51                 } else {
  52                         global $wgTitle;
  53                         $this->mTitle = $wgTitle;
  54                 }
  55                 wfDebug("DifferenceEngine old '$old' new '$new' rcid '$rcid'\n");
  56
  57                 if ( 'prev' === $new ) {
  58                         # Show diff between revision $old and the previous one.
  59                         # Get previous one from DB.
  60                         $this->mNewid = intval($old);
  61                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  62                 } elseif ( 'next' === $new ) {
  63                         # Show diff between revision $old and the next one.
  64                         # Get next one from DB.
  65                         $this->mOldid = intval($old);
  66                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  67                         if ( false === $this->mNewid ) {
  68                                 # if no result, NewId points to the newest old revision. The only newer
  69                                 # revision is cur, which is "0".
  70                                 $this->mNewid = 0;
  71                         }
  72                 } else {
  73                         $this->mOldid = intval($old);
  74                         $this->mNewid = intval($new);
  75                         wfRunHooks( 'NewDifferenceEngine', array(&$titleObj, &$this->mOldid, &$this->mNewid, $old, $new) );
  76                 }
  77                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  78                 $this->mRefreshCache = $refreshCache;
  79                 $this->htmldiff = $htmldiff;
  80                 $this->unhide = $unhide;
  81         }
  82
  83         function getTitle() {
  84                 return $this->mTitle;
  85         }
  86
  87         function wasCacheHit() {
  88                 return $this->mCacheHit;
  89         }
  90
  91         function getOldid() {
  92                 return $this->mOldid;
  93         }
  94
  95         function getNewid() {
  96                 return $this->mNewid;
  97         }
  98
  99         function showDiffPage( $diffOnly = false ) {
 100                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol, $wgEnableHtmlDiff;
 101                 wfProfileIn( __METHOD__ );
 102
 103
 104                 # If external diffs are enabled both globally and for the user,
 105                 # we'll use the application/x-external-editor interface to call
 106                 # an external diff tool like kompare, kdiff3, etc.
 107                 if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
 108                         global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
 109                         $wgOut->disable();
 110                         header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
 111                         $url1=$this->mTitle->getFullURL( array(
 112                                 'action' => 'raw',
 113                                 'oldid' => $this->mOldid
 114                         ) );
 115                         $url2=$this->mTitle->getFullURL( array(
 116                                 'action' => 'raw',
 117                                 'oldid' => $this->mNewid
 118                         ) );
 119                         $special=$wgLang->getNsText(NS_SPECIAL);
 120                         $control=<<<CONTROL
 121                         [Process]
 122                         Type=Diff text
 123                         Engine=MediaWiki
 124                         Script={$wgServer}{$wgScript}
 125                         Special namespace={$special}
 126
 127                         [File]
 128                         Extension=wiki
 129                         URL=$url1
 130
 131                         [File 2]
 132                         Extension=wiki
 133                         URL=$url2
 134 CONTROL;
 135                         echo($control);
 136                         return;
 137                 }
 138
 139                 $wgOut->setArticleFlag( false );
 140                 if ( !$this->loadRevisionData() ) {
 141                         $t = $this->mTitle->getPrefixedText();
 142                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 143                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 144                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 145                         wfProfileOut( __METHOD__ );
 146                         return;
 147                 }
 148
 149                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 150
 151                 if ( $this->mNewRev->isCurrent() ) {
 152                         $wgOut->setArticleFlag( true );
 153                 }
 154
 155                 # mOldid is false if the difference engine is called with a "vague" query for
 156                 # a diff between a version V and its previous version V' AND the version V
 157                 # is the first version of that article. In that case, V' does not exist.
 158                 if ( $this->mOldid === false ) {
 159                         $this->showFirstRevision();
 160                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 161                         wfProfileOut( __METHOD__ );
 162                         return;
 163                 }
 164
 165                 $wgOut->suppressQuickbar();
 166
 167                 $oldTitle = $this->mOldPage->getPrefixedText();
 168                 $newTitle = $this->mNewPage->getPrefixedText();
 169                 if( $oldTitle == $newTitle ) {
 170                         $wgOut->setPageTitle( $newTitle );
 171                 } else {
 172                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 173                 }
 174                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 175                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 176
 177                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 178                         $wgOut->loginToUse();
 179                         $wgOut->output();
 180                         $wgOut->disable();
 181                         wfProfileOut( __METHOD__ );
 182                         return;
 183                 }
 184
 185                 $sk = $wgUser->getSkin();
 186
 187                 // Check if page is editable
 188                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 189                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 190                         $rollback = '&nbsp;&nbsp;&nbsp;' . $sk->generateRollback( $this->mNewRev );
 191                 } else {
 192                         $rollback = '';
 193                 }
 194
 195                 // Prepare a change patrol link, if applicable
 196                 if( $wgUseRCPatrol && $this->mTitle->userCan('patrol') ) {
 197                         // If we've been given an explicit change identifier, use it; saves time
 198                         if( $this->mRcidMarkPatrolled ) {
 199                                 $rcid = $this->mRcidMarkPatrolled;
 200                                 $rc = RecentChange::newFromId( $rcid );
 201                                 // Already patrolled?
 202                                 $rcid = is_object($rc) && !$rc->getAttribute('rc_patrolled') ? $rcid : 0;
 203                         } else {
 204                                 // Look for an unpatrolled change corresponding to this diff
 205                                 $db = wfGetDB( DB_SLAVE );
 206                                 $change = RecentChange::newFromConds(
 207                                         array(
 208                                         // Redundant user,timestamp condition so we can use the existing index
 209                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 210                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 211                                                 'rc_this_oldid' => $this->mNewid,
 212                                                 'rc_last_oldid' => $this->mOldid,
 213                                                 'rc_patrolled'  => 0
 214                                         ),
 215                                         __METHOD__
 216                                 );
 217                                 if( $change instanceof RecentChange ) {
 218                                         $rcid = $change->mAttribs['rc_id'];
 219                                         $this->mRcidMarkPatrolled = $rcid;
 220                                 } else {
 221                                         // None found
 222                                         $rcid = 0;
 223                                 }
 224                         }
 225                         // Build the link
 226                         if( $rcid ) {
 227                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 228                                         $this->mTitle,
 229                                         wfMsgHtml( 'markaspatrolleddiff' ),
 230                                         array(),
 231                                         array(
 232                                                 'action' => 'markpatrolled',
 233                                                 'rcid' => $rcid
 234                                         ),
 235                                         array(
 236                                                 'known',
 237                                                 'noclasses'
 238                                         )
 239                                 ) . ']</span>';
 240                         } else {
 241                                 $patrol = '';
 242                         }
 243                 } else {
 244                         $patrol = '';
 245                 }
 246
 247                 # Carry over 'diffonly' param via navigation links
 248                 if( $diffOnly != $wgUser->getBoolOption('diffonly') ) {
 249                         $query['diffonly'] = $diffOnly;
 250                 }
 251
 252                 $htmldiffarg = $this->htmlDiffArgument();
 253
 254                 if( $htmldiffarg ) {
 255                         $query['htmldiff'] = $htmldiffarg['htmldiff'];
 256                 }
 257
 258                 # Make "previous revision link"
 259                 $query['diff'] = 'prev';
 260                 $query['oldid'] = $this->mOldid;
 261
 262                 $prevlink = $sk->link(
 263                         $this->mTitle,
 264                         wfMsgHtml( 'previousdiff' ),
 265                         array(
 266                                 'id' => 'differences-prevlink'
 267                         ),
 268                         $query,
 269                         array(
 270                                 'known',
 271                                 'noclasses'
 272                         )
 273                 );
 274                 # Make "next revision link"
 275                 $query['diff'] = 'next';
 276                 $query['oldid'] = $this->mNewid;
 277
 278                 if( $this->mNewRev->isCurrent() ) {
 279                         $nextlink = '&nbsp;';
 280                 } else {
 281                         $nextlink = $sk->link(
 282                                 $this->mTitle,
 283                                 wfMsgHtml( 'nextdiff' ),
 284                                 array(
 285                                         'id' => 'differences-nextlink'
 286                                 ),
 287                                 $query,
 288                                 array(
 289                                         'known',
 290                                         'noclasses'
 291                                 )
 292                         );
 293                 }
 294
 295                 $oldminor = '';
 296                 $newminor = '';
 297
 298                 if( $this->mOldRev->isMinor() ) {
 299                         $oldminor = ChangesList::flag( 'minor' );
 300                 }
 301                 if( $this->mNewRev->isMinor() ) {
 302                         $newminor = ChangesList::flag( 'minor' );
 303                 }
 304
 305                 $rdel = ''; $ldel = '';
 306                 if( $wgUser->isAllowed( 'deleterevision' ) ) {
 307                         if( !$this->mOldRev->userCan( Revision::DELETED_RESTRICTED ) ) {
 308                                 // If revision was hidden from sysops
 309                                 $ldel = Xml::tags( 'span', array( 'class' => 'mw-revdelundel-link' ), '(' . wfMsgHtml( 'rev-delundel' ) . ')' );
 310                         } else {
 311                                 $query = array(
 312                                         'type' => 'revision',
 313                                         'target' => $this->mOldRev->mTitle->getPrefixedDbkey(),
 314                                         'ids' => $this->mOldRev->getId()
 315                                 );
 316                                 $ldel = $sk->revDeleteLink( $query, $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) );
 317                         }
 318                         $ldel = "&nbsp;&nbsp;&nbsp;$ldel ";
 319                         if( !$this->mNewRev->userCan( Revision::DELETED_RESTRICTED ) ) {
 320                                 // If revision was hidden from sysops
 321                                 $rdel = Xml::tags( 'span', array( 'class'=>'mw-revdelundel-link' ), '('.wfMsgHtml( 'rev-delundel' ).')' );
 322                         } else {
 323                                 $query = array(
 324                                         'type' => 'revision',
 325                                         'target' =>  $this->mNewRev->mTitle->getPrefixedDbkey(),
 326                                         'ids' => $this->mNewRev->getId()
 327                                 );
 328                                 $rdel = $sk->revDeleteLink( $query, $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) );
 329                         }
 330                         $rdel = "&nbsp;&nbsp;&nbsp;$rdel ";
 331                 }
 332
 333                 $oldHeader = '<div id="mw-diff-otitle1"><strong>'.$this->mOldtitle.'</strong></div>' .
 334                         '<div id="mw-diff-otitle2">' . $sk->revUserTools( $this->mOldRev, !$this->unhide ) . "</div>" .
 335                         '<div id="mw-diff-otitle3">' . $oldminor . $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ).$ldel."</div>" .
 336                         '<div id="mw-diff-otitle4">' . $prevlink .'</div>';
 337                 $newHeader = '<div id="mw-diff-ntitle1"><strong>'.$this->mNewtitle.'</strong></div>' .
 338                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) . " $rollback</div>" .
 339                         '<div id="mw-diff-ntitle3">' . $newminor . $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ).$rdel."</div>" .
 340                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 341
 342                 # Check if this user can see the revisions
 343                 $allowed = $this->mOldRev->userCan(Revision::DELETED_TEXT)
 344                         && $this->mNewRev->userCan(Revision::DELETED_TEXT);
 345                 $deleted = $this->mOldRev->isDeleted(Revision::DELETED_TEXT)
 346                         || $this->mNewRev->isDeleted(Revision::DELETED_TEXT);
 347                 # Output the diff if allowed...
 348                 if( $deleted && (!$this->unhide || !$allowed) ) {
 349                         $this->showDiffStyle();
 350                         $multi = $this->getMultiNotice();
 351                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 352                         if( !$allowed ) {
 353                                 # Give explanation for why revision is not visible
 354                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n",
 355                                         array( 'rev-deleted-no-diff' ) );
 356                         } else {
 357                                 # Give explanation and add a link to view the diff...
 358                                 $link = $this->mTitle->getFullUrl( array(
 359                                         'diff' => $this->mNewid,
 360                                         'oldid' => $this->mOldid,
 361                                         'unhide' => 1
 362                                 ) );
 363                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n",
 364                                         array( 'rev-deleted-unhide-diff', $link ) );
 365                         }
 366                 } else if( $wgEnableHtmlDiff && $this->htmldiff ) {
 367                         $multi = $this->getMultiNotice();
 368                         $wgOut->addHTML( '<div class="diff-switchtype">' . $sk->link(
 369                                 $this->mTitle,
 370                                 wfMsgHtml( 'wikicodecomparison' ),
 371                                 array(
 372                                         'id' => 'differences-switchtype'
 373                                 ),
 374                                 array(
 375                                         'diff' => $this->mNewid,
 376                                         'oldid' => $this->mOldid,
 377                                         'htmldiff' => 0
 378                                 ),
 379                                 array(
 380                                         'known',
 381                                         'noclasses'
 382                                 )
 383                         ) . '</div>');
 384                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 385                         $this->renderHtmlDiff();
 386                 } else {
 387                         if( $wgEnableHtmlDiff ) {
 388                                 $wgOut->addHTML( '<div class="diff-switchtype">' . $sk->link(
 389                                         $this->mTitle,
 390                                         wfMsgHtml( 'visualcomparison' ),
 391                                         array(
 392                                                 'id' => 'differences-switchtype'
 393                                         ),
 394                                         array(
 395                                                 'diff' => $this->mNewid,
 396                                                 'oldid' => $this->mOldid,
 397                                                 'htmldiff' => 1
 398                                         ),
 399                                         array(
 400                                                 'known',
 401                                                 'noclasses'
 402                                         )
 403                                 ) . '</div>');
 404                         }
 405                         $this->showDiff( $oldHeader, $newHeader );
 406                         if( !$diffOnly ) {
 407                                 $this->renderNewRevision();
 408                         }
 409                 }
 410                 wfProfileOut( __METHOD__ );
 411         }
 412
 413         /**
 414          * Show the new revision of the page.
 415          */
 416         function renderNewRevision() {
 417                 global $wgOut, $wgUser;
 418                 wfProfileIn( __METHOD__ );
 419
 420                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 421                 # Add deleted rev tag if needed
 422                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 423                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-permission' );
 424                 } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 425                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-view' );
 426                 }
 427
 428                 if( !$this->mNewRev->isCurrent() ) {
 429                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 430                 }
 431
 432                 $this->loadNewText();
 433                 if( is_object( $this->mNewRev ) ) {
 434                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 435                 }
 436
 437                 if( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 438                         // Stolen from Article::view --AG 2007-10-11
 439                         // Give hooks a chance to customise the output
 440                         if( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 441                                 // Wrap the whole lot in a <pre> and don't parse
 442                                 $m = array();
 443                                 preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 444                                 $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 445                                 $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 446                                 $wgOut->addHTML( "\n</pre>\n" );
 447                         }
 448                 } else {
 449                         $wgOut->addWikiTextTidy( $this->mNewtext );
 450                 }
 451
 452                 if( is_object( $this->mNewRev ) && !$this->mNewRev->isCurrent() ) {
 453                         $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 454                 }
 455                 # Add redundant patrol link on bottom...
 456                 if( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan('patrol') ) {
 457                         $sk = $wgUser->getSkin();
 458                         $wgOut->addHTML(
 459                                 "<div class='patrollink'>[" . $sk->link(
 460                                         $this->mTitle,
 461                                         wfMsgHtml( 'markaspatrolleddiff' ),
 462                                         array(),
 463                                         array(
 464                                                 'action' => 'markpatrolled',
 465                                                 'rcid' => $this->mRcidMarkPatrolled
 466                                         )
 467                                 ) . ']</div>'
 468                          );
 469                 }
 470
 471                 wfProfileOut( __METHOD__ );
 472         }
 473
 474
 475         function renderHtmlDiff() {
 476                 global $wgOut, $wgParser, $wgDebugComments;
 477                 wfProfileIn( __METHOD__ );
 478
 479                 $this->showDiffStyle();
 480
 481                 $wgOut->addHTML( '<h2>'.wfMsgHtml( 'visual-comparison' )."</h2>\n" );
 482                 #add deleted rev tag if needed
 483                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 484                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-permission' );
 485                 } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 486                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-view' );
 487                 }
 488
 489                 if( !$this->mNewRev->isCurrent() ) {
 490                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 491                 }
 492
 493                 $this->loadText();
 494
 495                 // Old revision
 496                 if( is_object( $this->mOldRev ) ) {
 497                         $wgOut->setRevisionId( $this->mOldRev->getId() );
 498                 }
 499
 500                 $popts = $wgOut->parserOptions();
 501                 $oldTidy = $popts->setTidy( true );
 502                 $popts->setEditSection( false );
 503
 504                 $parserOutput = $wgParser->parse( $this->mOldtext, $this->getTitle(), $popts, true, true, $wgOut->getRevisionId() );
 505                 $popts->setTidy( $oldTidy );
 506
 507                 //only for new?
 508                 //$wgOut->addParserOutputNoText( $parserOutput );
 509                 $oldHtml = $parserOutput->getText();
 510                 wfRunHooks( 'OutputPageBeforeHTML', array( &$wgOut, &$oldHtml ) );
 511
 512                 // New revision
 513                 if( is_object( $this->mNewRev ) ) {
 514                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 515                 }
 516
 517                 $popts = $wgOut->parserOptions();
 518                 $oldTidy = $popts->setTidy( true );
 519
 520                 $parserOutput = $wgParser->parse( $this->mNewtext, $this->getTitle(), $popts, true, true, $wgOut->getRevisionId() );
 521                 $popts->setTidy( $oldTidy );
 522
 523                 $wgOut->addParserOutputNoText( $parserOutput );
 524                 $newHtml = $parserOutput->getText();
 525                 wfRunHooks( 'OutputPageBeforeHTML', array( &$wgOut, &$newHtml ) );
 526
 527                 unset($parserOutput, $popts);
 528
 529                 $differ = new HTMLDiffer(new DelegatingContentHandler($wgOut));
 530                 $differ->htmlDiff($oldHtml, $newHtml);
 531                 if ( $wgDebugComments ) {
 532                         $wgOut->addHTML( "\n<!-- HtmlDiff Debug Output:\n" . HTMLDiffer::getDebugOutput() . " End Debug -->" );
 533                 }
 534
 535                 wfProfileOut( __METHOD__ );
 536         }
 537
 538         /**
 539          * Show the first revision of an article. Uses normal diff headers in
 540          * contrast to normal "old revision" display style.
 541          */
 542         function showFirstRevision() {
 543                 global $wgOut, $wgUser;
 544                 wfProfileIn( __METHOD__ );
 545
 546                 # Get article text from the DB
 547                 #
 548                 if ( ! $this->loadNewText() ) {
 549                         $t = $this->mTitle->getPrefixedText();
 550                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 551                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 552                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 553                         wfProfileOut( __METHOD__ );
 554                         return;
 555                 }
 556                 if ( $this->mNewRev->isCurrent() ) {
 557                         $wgOut->setArticleFlag( true );
 558                 }
 559
 560                 # Check if user is allowed to look at this page. If not, bail out.
 561                 #
 562                 if ( !$this->mTitle->userCanRead() ) {
 563                         $wgOut->loginToUse();
 564                         $wgOut->output();
 565                         wfProfileOut( __METHOD__ );
 566                         throw new MWException("Permission Error: you do not have access to view this page");
 567                 }
 568
 569                 # Prepare the header box
 570                 #
 571                 $sk = $wgUser->getSkin();
 572
 573                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 574                 if( !$next ) {
 575                         $nextlink = '';
 576                 } else {
 577                         $nextlink = '<br/>' . $sk->link(
 578                                 $this->mTitle,
 579                                 wfMsgHtml( 'nextdiff' ),
 580                                 array(
 581                                         'id' => 'differences-nextlink'
 582                                 ),
 583                                 array(
 584                                         'diff' => 'next',
 585                                         'oldid' => $this->mNewid,
 586                                         $this->htmlDiffArgument()
 587                                 ),
 588                                 array(
 589                                         'known',
 590                                         'noclasses'
 591                                 )
 592                         );
 593                 }
 594                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 595                         $sk->revUserTools( $this->mNewRev ) . "<br/>" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 596
 597                 $wgOut->addHTML( $header );
 598
 599                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 600                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 601
 602                 wfProfileOut( __METHOD__ );
 603         }
 604
 605         function htmlDiffArgument(){
 606                 global $wgEnableHtmlDiff;
 607                 if($wgEnableHtmlDiff){
 608                         if($this->htmldiff){
 609                                 return array( 'htmldiff' => 1 );
 610                         }else{
 611                                 return array( 'htmldiff' => 0 );
 612                         }
 613                 }else{
 614                         return array();
 615                 }
 616         }
 617
 618         /**
 619          * Get the diff text, send it to $wgOut
 620          * Returns false if the diff could not be generated, otherwise returns true
 621          */
 622         function showDiff( $otitle, $ntitle ) {
 623                 global $wgOut;
 624                 $diff = $this->getDiff( $otitle, $ntitle );
 625                 if ( $diff === false ) {
 626                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 627                         return false;
 628                 } else {
 629                         $this->showDiffStyle();
 630                         $wgOut->addHTML( $diff );
 631                         return true;
 632                 }
 633         }
 634
 635         /**
 636          * Add style sheets and supporting JS for diff display.
 637          */
 638         function showDiffStyle() {
 639                 global $wgStylePath, $wgStyleVersion, $wgOut;
 640                 $wgOut->addStyle( 'common/diff.css' );
 641
 642                 // JS is needed to detect old versions of Mozilla to work around an annoyance bug.
 643                 $wgOut->addScript( "<script type=\"text/javascript\" src=\"$wgStylePath/common/diff.js?$wgStyleVersion\"></script>" );
 644         }
 645
 646         /**
 647          * Get complete diff table, including header
 648          *
 649          * @param Title $otitle Old title
 650          * @param Title $ntitle New title
 651          * @return mixed
 652          */
 653         function getDiff( $otitle, $ntitle ) {
 654                 $body = $this->getDiffBody();
 655                 if ( $body === false ) {
 656                         return false;
 657                 } else {
 658                         $multi = $this->getMultiNotice();
 659                         return $this->addHeader( $body, $otitle, $ntitle, $multi );
 660                 }
 661         }
 662
 663         /**
 664          * Get the diff table body, without header
 665          *
 666          * @return mixed
 667          */
 668         function getDiffBody() {
 669                 global $wgMemc;
 670                 wfProfileIn( __METHOD__ );
 671                 $this->mCacheHit = true;
 672                 // Check if the diff should be hidden from this user
 673                 if ( !$this->loadRevisionData() )
 674                         return '';
 675                 if ( $this->mOldRev && !$this->mOldRev->userCan(Revision::DELETED_TEXT) ) {
 676                         return '';
 677                 } else if ( $this->mNewRev && !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 678                         return '';
 679                 } else if ( $this->mOldRev && $this->mNewRev && $this->mOldRev->getID() == $this->mNewRev->getID() ) {
 680                         return '';
 681                 }
 682                 // Cacheable?
 683                 $key = false;
 684                 if ( $this->mOldid && $this->mNewid ) {
 685                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION, 'oldid', $this->mOldid, 'newid', $this->mNewid );
 686                         // Try cache
 687                         if ( !$this->mRefreshCache ) {
 688                                 $difftext = $wgMemc->get( $key );
 689                                 if ( $difftext ) {
 690                                         wfIncrStats( 'diff_cache_hit' );
 691                                         $difftext = $this->localiseLineNumbers( $difftext );
 692                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 693                                         wfProfileOut( __METHOD__ );
 694                                         return $difftext;
 695                                 }
 696                         } // don't try to load but save the result
 697                 }
 698                 $this->mCacheHit = false;
 699
 700                 // Loadtext is permission safe, this just clears out the diff
 701                 if ( !$this->loadText() ) {
 702                         wfProfileOut( __METHOD__ );
 703                         return false;
 704                 }
 705
 706                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 707
 708                 // Save to cache for 7 days
 709                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 710                         wfIncrStats( 'diff_uncacheable' );
 711                 } else if ( $key !== false && $difftext !== false ) {
 712                         wfIncrStats( 'diff_cache_miss' );
 713                         $wgMemc->set( $key, $difftext, 7*86400 );
 714                 } else {
 715                         wfIncrStats( 'diff_uncacheable' );
 716                 }
 717                 // Replace line numbers with the text in the user's language
 718                 if ( $difftext !== false ) {
 719                         $difftext = $this->localiseLineNumbers( $difftext );
 720                 }
 721                 wfProfileOut( __METHOD__ );
 722                 return $difftext;
 723         }
 724
 725         /**
 726          * Make sure the proper modules are loaded before we try to
 727          * make the diff
 728          */
 729         private function initDiffEngines() {
 730                 global $wgExternalDiffEngine;
 731                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 732                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 733                         wfSuppressWarnings();
 734                         dl( 'php_wikidiff.so' );
 735                         wfRestoreWarnings();
 736                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 737                 }
 738                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 739                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 740                         wfSuppressWarnings();
 741                         dl( 'php_wikidiff2.so' );
 742                         wfRestoreWarnings();
 743                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 744                 }
 745         }
 746
 747         /**
 748          * Generate a diff, no caching
 749          * $otext and $ntext must be already segmented
 750          */
 751         function generateDiffBody( $otext, $ntext ) {
 752                 global $wgExternalDiffEngine, $wgContLang;
 753
 754                 $otext = str_replace( "\r\n", "\n", $otext );
 755                 $ntext = str_replace( "\r\n", "\n", $ntext );
 756
 757                 $this->initDiffEngines();
 758
 759                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 760                         # For historical reasons, external diff engine expects
 761                         # input text to be HTML-escaped already
 762                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 763                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 764                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 765                         $this->debug( 'wikidiff1' );
 766                 }
 767
 768                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 769                         # Better external diff engine, the 2 may some day be dropped
 770                         # This one does the escaping and segmenting itself
 771                         wfProfileIn( 'wikidiff2_do_diff' );
 772                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 773                         $text .= $this->debug( 'wikidiff2' );
 774                         wfProfileOut( 'wikidiff2_do_diff' );
 775                         return $text;
 776                 }
 777                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 778                         # Diff via the shell
 779                         global $wgTmpDirectory;
 780                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 781                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 782
 783                         $tempFile1 = fopen( $tempName1, "w" );
 784                         if ( !$tempFile1 ) {
 785                                 wfProfileOut( __METHOD__ );
 786                                 return false;
 787                         }
 788                         $tempFile2 = fopen( $tempName2, "w" );
 789                         if ( !$tempFile2 ) {
 790                                 wfProfileOut( __METHOD__ );
 791                                 return false;
 792                         }
 793                         fwrite( $tempFile1, $otext );
 794                         fwrite( $tempFile2, $ntext );
 795                         fclose( $tempFile1 );
 796                         fclose( $tempFile2 );
 797                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 798                         wfProfileIn( __METHOD__ . "-shellexec" );
 799                         $difftext = wfShellExec( $cmd );
 800                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 801                         wfProfileOut( __METHOD__ . "-shellexec" );
 802                         unlink( $tempName1 );
 803                         unlink( $tempName2 );
 804                         return $difftext;
 805                 }
 806
 807                 # Native PHP diff
 808                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 809                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 810                 $diffs = new Diff( $ota, $nta );
 811                 $formatter = new TableDiffFormatter();
 812                 return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 813                 $this->debug();
 814         }
 815
 816         /**
 817          * Generate a debug comment indicating diff generating time,
 818          * server node, and generator backend.
 819          */
 820         protected function debug( $generator="internal" ) {
 821                 global $wgShowHostnames;
 822                 $data = array( $generator );
 823                 if( $wgShowHostnames ) {
 824                         $data[] = wfHostname();
 825                 }
 826                 $data[] = wfTimestamp( TS_DB );
 827                 return "<!-- diff generator: " .
 828                 implode( " ",
 829                 array_map(
 830                                         "htmlspecialchars",
 831                 $data ) ) .
 832                         " -->\n";
 833         }
 834
 835         /**
 836          * Replace line numbers with the text in the user's language
 837          */
 838         function localiseLineNumbers( $text ) {
 839                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 840                 array( &$this, 'localiseLineNumbersCb' ), $text );
 841         }
 842
 843         function localiseLineNumbersCb( $matches ) {
 844                 global $wgLang;
 845                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 846         }
 847
 848
 849         /**
 850          * If there are revisions between the ones being compared, return a note saying so.
 851          */
 852         function getMultiNotice() {
 853                 if ( !is_object($this->mOldRev) || !is_object($this->mNewRev) )
 854                 return '';
 855
 856                 if( !$this->mOldPage->equals( $this->mNewPage ) ) {
 857                         // Comparing two different pages? Count would be meaningless.
 858                         return '';
 859                 }
 860
 861                 $oldid = $this->mOldRev->getId();
 862                 $newid = $this->mNewRev->getId();
 863                 if ( $oldid > $newid ) {
 864                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 865                 }
 866
 867                 $n = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 868                 if ( !$n )
 869                 return '';
 870
 871                 return wfMsgExt( 'diff-multi', array( 'parseinline' ), $n );
 872         }
 873
 874
 875         /**
 876          * Add the header to a diff body
 877          */
 878         static function addHeader( $diff, $otitle, $ntitle, $multi = '' ) {
 879                 $colspan = 1;
 880                 $header = "<table class='diff'>";
 881                 if( $diff ) { // Safari/Chrome show broken output if cols not used
 882                         $header .= "
 883                         <col class='diff-marker' />
 884                         <col class='diff-content' />
 885                         <col class='diff-marker' />
 886                         <col class='diff-content' />";
 887                         $colspan = 2;
 888                 }
 889                 $header .= "
 890                 <tr valign='top'>
 891                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 892                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 893                 </tr>";
 894
 895                 if ( $multi != '' )
 896                 $header .= "<tr><td colspan='4' align='center' class='diff-multi'>{$multi}</td></tr>";
 897
 898                 return $header . $diff . "</table>";
 899         }
 900
 901         /**
 902          * Use specified text instead of loading from the database
 903          */
 904         function setText( $oldText, $newText ) {
 905                 $this->mOldtext = $oldText;
 906                 $this->mNewtext = $newText;
 907                 $this->mTextLoaded = 2;
 908                 $this->mRevisionsLoaded = true;
 909         }
 910
 911         /**
 912          * Load revision metadata for the specified articles. If newid is 0, then compare
 913          * the old article in oldid to the current article; if oldid is 0, then
 914          * compare the current article to the immediately previous one (ignoring the
 915          * value of newid).
 916          *
 917          * If oldid is false, leave the corresponding revision object set
 918          * to false. This is impossible via ordinary user input, and is provided for
 919          * API convenience.
 920          */
 921         function loadRevisionData() {
 922                 global $wgLang, $wgUser;
 923                 if ( $this->mRevisionsLoaded ) {
 924                         return true;
 925                 } else {
 926                         // Whether it succeeds or fails, we don't want to try again
 927                         $this->mRevisionsLoaded = true;
 928                 }
 929
 930                 // Load the new revision object
 931                 $this->mNewRev = $this->mNewid
 932                         ? Revision::newFromId( $this->mNewid )
 933                         : Revision::newFromTitle( $this->mTitle );
 934                 if( !$this->mNewRev instanceof Revision )
 935                         return false;
 936
 937                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 938                 $this->mNewid = $this->mNewRev->getId();
 939
 940                 // Check if page is editable
 941                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 942
 943                 // Set assorted variables
 944                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 945                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 946                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 947                 $this->mNewPage = $this->mNewRev->getTitle();
 948                 if( $this->mNewRev->isCurrent() ) {
 949                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 950                                 'oldid' => $this->mNewid
 951                         ) );
 952                         $this->mPagetitle = htmlspecialchars( wfMsg(
 953                                 'currentrev-asof',
 954                                 $timestamp,
 955                                 $dateofrev,
 956                                 $timeofrev
 957                         ) );
 958                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 959                                 'action' => 'edit'
 960                         ) );
 961
 962                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 963                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 964                 } else {
 965                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 966                                 'oldid' => $this->mNewid
 967                         ) );
 968                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 969                                 'action' => 'edit',
 970                                 'oldid' => $this->mNewid
 971                         ) );
 972                         $this->mPagetitle = htmlspecialchars( wfMsg(
 973                                 'revisionasof',
 974                                 $timestamp,
 975                                 $dateofrev,
 976                                 $timeofrev
 977                         ) );
 978
 979                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 980                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 981                 }
 982                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 983                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 984                 } else if ( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 985                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 986                 }
 987
 988                 // Load the old revision object
 989                 $this->mOldRev = false;
 990                 if( $this->mOldid ) {
 991                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 992                 } elseif ( $this->mOldid === 0 ) {
 993                         $rev = $this->mNewRev->getPrevious();
 994                         if( $rev ) {
 995                                 $this->mOldid = $rev->getId();
 996                                 $this->mOldRev = $rev;
 997                         } else {
 998                                 // No previous revision; mark to show as first-version only.
 999                                 $this->mOldid = false;
1000                                 $this->mOldRev = false;
1001                         }
1002                 }/* elseif ( $this->mOldid === false ) leave mOldRev false; */
1003
1004                 if( is_null( $this->mOldRev ) ) {
1005                         return false;
1006                 }
1007
1008                 if ( $this->mOldRev ) {
1009                         $this->mOldPage = $this->mOldRev->getTitle();
1010
1011                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1012                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1013                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1014                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1015                                 'oldid' => $this->mOldid
1016                         ) );
1017                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1018                                 'action' => 'edit',
1019                                 'oldid' => $this->mOldid
1020                         ) );
1021                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1022
1023                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1024                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1025                         // Add an "undo" link
1026                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
1027                                 'action' => 'edit',
1028                                 'undoafter' => $this->mOldid,
1029                                 'undo' => $this->mNewid
1030                         ) );
1031                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
1032                         $htmlTitle = $wgUser->getSkin()->tooltip( 'undo' );
1033                         if( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1034                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
1035                         }
1036
1037                         if( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1038                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1039                         } else if( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1040                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1041                         }
1042                 }
1043
1044                 return true;
1045         }
1046
1047         /**
1048          * Load the text of the revisions, as well as revision data.
1049          */
1050         function loadText() {
1051                 if ( $this->mTextLoaded == 2 ) {
1052                         return true;
1053                 } else {
1054                         // Whether it succeeds or fails, we don't want to try again
1055                         $this->mTextLoaded = 2;
1056                 }
1057
1058                 if ( !$this->loadRevisionData() ) {
1059                         return false;
1060                 }
1061                 if ( $this->mOldRev ) {
1062                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1063                         if ( $this->mOldtext === false ) {
1064                                 return false;
1065                         }
1066                 }
1067                 if ( $this->mNewRev ) {
1068                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1069                         if ( $this->mNewtext === false ) {
1070                                 return false;
1071                         }
1072                 }
1073                 return true;
1074         }
1075
1076         /**
1077          * Load the text of the new revision, not the old one
1078          */
1079         function loadNewText() {
1080                 if ( $this->mTextLoaded >= 1 ) {
1081                         return true;
1082                 } else {
1083                         $this->mTextLoaded = 1;
1084                 }
1085                 if ( !$this->loadRevisionData() ) {
1086                         return false;
1087                 }
1088                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1089                 return true;
1090         }
1091 }
1092
1093 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
1094 //
1095 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
1096 // You may copy this code freely under the conditions of the GPL.
1097 //
1098
1099 define('USE_ASSERTS', function_exists('assert'));
1100
1101 /**
1102  * @todo document
1103  * @private
1104  * @ingroup DifferenceEngine
1105  */
1106 class _DiffOp {
1107         var $type;
1108         var $orig;
1109         var $closing;
1110
1111         function reverse() {
1112                 trigger_error('pure virtual', E_USER_ERROR);
1113         }
1114
1115         function norig() {
1116                 return $this->orig ? sizeof($this->orig) : 0;
1117         }
1118
1119         function nclosing() {
1120                 return $this->closing ? sizeof($this->closing) : 0;
1121         }
1122 }
1123
1124 /**
1125  * @todo document
1126  * @private
1127  * @ingroup DifferenceEngine
1128  */
1129 class _DiffOp_Copy extends _DiffOp {
1130         var $type = 'copy';
1131
1132         function _DiffOp_Copy ($orig, $closing = false) {
1133                 if (!is_array($closing))
1134                 $closing = $orig;
1135                 $this->orig = $orig;
1136                 $this->closing = $closing;
1137         }
1138
1139         function reverse() {
1140                 return new _DiffOp_Copy($this->closing, $this->orig);
1141         }
1142 }
1143
1144 /**
1145  * @todo document
1146  * @private
1147  * @ingroup DifferenceEngine
1148  */
1149 class _DiffOp_Delete extends _DiffOp {
1150         var $type = 'delete';
1151
1152         function _DiffOp_Delete ($lines) {
1153                 $this->orig = $lines;
1154                 $this->closing = false;
1155         }
1156
1157         function reverse() {
1158                 return new _DiffOp_Add($this->orig);
1159         }
1160 }
1161
1162 /**
1163  * @todo document
1164  * @private
1165  * @ingroup DifferenceEngine
1166  */
1167 class _DiffOp_Add extends _DiffOp {
1168         var $type = 'add';
1169
1170         function _DiffOp_Add ($lines) {
1171                 $this->closing = $lines;
1172                 $this->orig = false;
1173         }
1174
1175         function reverse() {
1176                 return new _DiffOp_Delete($this->closing);
1177         }
1178 }
1179
1180 /**
1181  * @todo document
1182  * @private
1183  * @ingroup DifferenceEngine
1184  */
1185 class _DiffOp_Change extends _DiffOp {
1186         var $type = 'change';
1187
1188         function _DiffOp_Change ($orig, $closing) {
1189                 $this->orig = $orig;
1190                 $this->closing = $closing;
1191         }
1192
1193         function reverse() {
1194                 return new _DiffOp_Change($this->closing, $this->orig);
1195         }
1196 }
1197
1198 /**
1199  * Class used internally by Diff to actually compute the diffs.
1200  *
1201  * The algorithm used here is mostly lifted from the perl module
1202  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
1203  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
1204  *
1205  * More ideas are taken from:
1206  *       http://www.ics.uci.edu/~eppstein/161/960229.html
1207  *
1208  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
1209  * diffutils-2.7, which can be found at:
1210  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
1211  *
1212  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
1213  * are my own.
1214  *
1215  * Line length limits for robustness added by Tim Starling, 2005-08-31
1216  * Alternative implementation added by Guy Van den Broeck, 2008-07-30
1217  *
1218  * @author Geoffrey T. Dairiki, Tim Starling, Guy Van den Broeck
1219  * @private
1220  * @ingroup DifferenceEngine
1221  */
1222 class _DiffEngine {
1223
1224         const MAX_XREF_LENGTH =  10000;
1225
1226         function diff ($from_lines, $to_lines){
1227                 wfProfileIn( __METHOD__ );
1228
1229                 // Diff and store locally
1230                 $this->diff_local($from_lines, $to_lines);
1231
1232                 // Merge edits when possible
1233                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
1234                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
1235
1236                 // Compute the edit operations.
1237                 $n_from = sizeof($from_lines);
1238                 $n_to = sizeof($to_lines);
1239
1240                 $edits = array();
1241                 $xi = $yi = 0;
1242                 while ($xi < $n_from || $yi < $n_to) {
1243                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
1244                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
1245
1246                         // Skip matching "snake".
1247                         $copy = array();
1248                         while ( $xi < $n_from && $yi < $n_to
1249                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
1250                                 $copy[] = $from_lines[$xi++];
1251                                 ++$yi;
1252                         }
1253                         if ($copy)
1254                         $edits[] = new _DiffOp_Copy($copy);
1255
1256                         // Find deletes & adds.
1257                         $delete = array();
1258                         while ($xi < $n_from && $this->xchanged[$xi])
1259                         $delete[] = $from_lines[$xi++];
1260
1261                         $add = array();
1262                         while ($yi < $n_to && $this->ychanged[$yi])
1263                         $add[] = $to_lines[$yi++];
1264
1265                         if ($delete && $add)
1266                         $edits[] = new _DiffOp_Change($delete, $add);
1267                         elseif ($delete)
1268                         $edits[] = new _DiffOp_Delete($delete);
1269                         elseif ($add)
1270                         $edits[] = new _DiffOp_Add($add);
1271                 }
1272                 wfProfileOut( __METHOD__ );
1273                 return $edits;
1274         }
1275
1276         function diff_local ($from_lines, $to_lines) {
1277                 global $wgExternalDiffEngine;
1278                 wfProfileIn( __METHOD__);
1279
1280                 if($wgExternalDiffEngine == 'wikidiff3'){
1281                         // wikidiff3
1282                         $wikidiff3 = new WikiDiff3();
1283                         $wikidiff3->diff($from_lines, $to_lines);
1284                         $this->xchanged = $wikidiff3->removed;
1285                         $this->ychanged = $wikidiff3->added;
1286                         unset($wikidiff3);
1287                 }else{
1288                         // old diff
1289                         $n_from = sizeof($from_lines);
1290                         $n_to = sizeof($to_lines);
1291                         $this->xchanged = $this->ychanged = array();
1292                         $this->xv = $this->yv = array();
1293                         $this->xind = $this->yind = array();
1294                         unset($this->seq);
1295                         unset($this->in_seq);
1296                         unset($this->lcs);
1297
1298                         // Skip leading common lines.
1299                         for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
1300                                 if ($from_lines[$skip] !== $to_lines[$skip])
1301                                 break;
1302                                 $this->xchanged[$skip] = $this->ychanged[$skip] = false;
1303                         }
1304                         // Skip trailing common lines.
1305                         $xi = $n_from; $yi = $n_to;
1306                         for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
1307                                 if ($from_lines[$xi] !== $to_lines[$yi])
1308                                 break;
1309                                 $this->xchanged[$xi] = $this->ychanged[$yi] = false;
1310                         }
1311
1312                         // Ignore lines which do not exist in both files.
1313                         for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
1314                                 $xhash[$this->_line_hash($from_lines[$xi])] = 1;
1315                         }
1316
1317                         for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
1318                                 $line = $to_lines[$yi];
1319                                 if ( ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) )
1320                                 continue;
1321                                 $yhash[$this->_line_hash($line)] = 1;
1322                                 $this->yv[] = $line;
1323                                 $this->yind[] = $yi;
1324                         }
1325                         for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
1326                                 $line = $from_lines[$xi];
1327                                 if ( ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) )
1328                                 continue;
1329                                 $this->xv[] = $line;
1330                                 $this->xind[] = $xi;
1331                         }
1332
1333                         // Find the LCS.
1334                         $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
1335                 }
1336                 wfProfileOut( __METHOD__ );
1337         }
1338
1339         /**
1340          * Returns the whole line if it's small enough, or the MD5 hash otherwise
1341          */
1342         function _line_hash( $line ) {
1343                 if ( strlen( $line ) > self::MAX_XREF_LENGTH ) {
1344                         return md5( $line );
1345                 } else {
1346                         return $line;
1347                 }
1348         }
1349
1350         /* Divide the Largest Common Subsequence (LCS) of the sequences
1351          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
1352          * sized segments.
1353          *
1354          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
1355          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
1356          * sub sequences.  The first sub-sequence is contained in [X0, X1),
1357          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
1358          * that (X0, Y0) == (XOFF, YOFF) and
1359          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
1360          *
1361          * This function assumes that the first lines of the specified portions
1362          * of the two files do not match, and likewise that the last lines do not
1363          * match.  The caller must trim matching lines from the beginning and end
1364          * of the portions it is going to specify.
1365          */
1366         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
1367                 $flip = false;
1368
1369                 if ($xlim - $xoff > $ylim - $yoff) {
1370                         // Things seems faster (I'm not sure I understand why)
1371                         // when the shortest sequence in X.
1372                         $flip = true;
1373                         list ($xoff, $xlim, $yoff, $ylim)
1374                         = array( $yoff, $ylim, $xoff, $xlim);
1375                 }
1376
1377                 if ($flip)
1378                 for ($i = $ylim - 1; $i >= $yoff; $i--)
1379                 $ymatches[$this->xv[$i]][] = $i;
1380                 else
1381                 for ($i = $ylim - 1; $i >= $yoff; $i--)
1382                 $ymatches[$this->yv[$i]][] = $i;
1383
1384                 $this->lcs = 0;
1385                 $this->seq[0]= $yoff - 1;
1386                 $this->in_seq = array();
1387                 $ymids[0] = array();
1388
1389                 $numer = $xlim - $xoff + $nchunks - 1;
1390                 $x = $xoff;
1391                 for ($chunk = 0; $chunk < $nchunks; $chunk++) {
1392                         if ($chunk > 0)
1393                         for ($i = 0; $i <= $this->lcs; $i++)
1394                         $ymids[$i][$chunk-1] = $this->seq[$i];
1395
1396                         $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
1397                         for ( ; $x < $x1; $x++) {
1398                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
1399                                 if (empty($ymatches[$line]))
1400                                 continue;
1401                                 $matches = $ymatches[$line];
1402                                 reset($matches);
1403                                 while (list ($junk, $y) = each($matches))
1404                                 if (empty($this->in_seq[$y])) {
1405                                         $k = $this->_lcs_pos($y);
1406                                         USE_ASSERTS && assert($k > 0);
1407                                         $ymids[$k] = $ymids[$k-1];
1408                                         break;
1409                                 }
1410                                 while (list ( /* $junk */, $y) = each($matches)) {
1411                                         if ($y > $this->seq[$k-1]) {
1412                                                 USE_ASSERTS && assert($y < $this->seq[$k]);
1413                                                 // Optimization: this is a common case:
1414                                                 //      next match is just replacing previous match.
1415                                                 $this->in_seq[$this->seq[$k]] = false;
1416                                                 $this->seq[$k] = $y;
1417                                                 $this->in_seq[$y] = 1;
1418                                         } else if (empty($this->in_seq[$y])) {
1419                                                 $k = $this->_lcs_pos($y);
1420                                                 USE_ASSERTS && assert($k > 0);
1421                                                 $ymids[$k] = $ymids[$k-1];
1422                                         }
1423                                 }
1424                         }
1425                 }
1426
1427                 $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
1428                 $ymid = $ymids[$this->lcs];
1429                 for ($n = 0; $n < $nchunks - 1; $n++) {
1430                         $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
1431                         $y1 = $ymid[$n] + 1;
1432                         $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
1433                 }
1434                 $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
1435
1436                 return array($this->lcs, $seps);
1437         }
1438
1439         function _lcs_pos ($ypos) {
1440                 $end = $this->lcs;
1441                 if ($end == 0 || $ypos > $this->seq[$end]) {
1442                         $this->seq[++$this->lcs] = $ypos;
1443                         $this->in_seq[$ypos] = 1;
1444                         return $this->lcs;
1445                 }
1446
1447                 $beg = 1;
1448                 while ($beg < $end) {
1449                         $mid = (int)(($beg + $end) / 2);
1450                         if ( $ypos > $this->seq[$mid] )
1451                         $beg = $mid + 1;
1452                         else
1453                         $end = $mid;
1454                 }
1455
1456                 USE_ASSERTS && assert($ypos != $this->seq[$end]);
1457
1458                 $this->in_seq[$this->seq[$end]] = false;
1459                 $this->seq[$end] = $ypos;
1460                 $this->in_seq[$ypos] = 1;
1461                 return $end;
1462         }
1463
1464         /* Find LCS of two sequences.
1465          *
1466          * The results are recorded in the vectors $this->{x,y}changed[], by
1467          * storing a 1 in the element for each line that is an insertion
1468          * or deletion (ie. is not in the LCS).
1469          *
1470          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
1471          *
1472          * Note that XLIM, YLIM are exclusive bounds.
1473          * All line numbers are origin-0 and discarded lines are not counted.
1474          */
1475         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
1476                 // Slide down the bottom initial diagonal.
1477                 while ($xoff < $xlim && $yoff < $ylim
1478                 && $this->xv[$xoff] == $this->yv[$yoff]) {
1479                         ++$xoff;
1480                         ++$yoff;
1481                 }
1482
1483                 // Slide up the top initial diagonal.
1484                 while ($xlim > $xoff && $ylim > $yoff
1485                 && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
1486                         --$xlim;
1487                         --$ylim;
1488                 }
1489
1490                 if ($xoff == $xlim || $yoff == $ylim)
1491                 $lcs = 0;
1492                 else {
1493                         // This is ad hoc but seems to work well.
1494                         //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
1495                         //$nchunks = max(2,min(8,(int)$nchunks));
1496                         $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
1497                         list ($lcs, $seps)
1498                         = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
1499                 }
1500
1501                 if ($lcs == 0) {
1502                         // X and Y sequences have no common subsequence:
1503                         // mark all changed.
1504                         while ($yoff < $ylim)
1505                         $this->ychanged[$this->yind[$yoff++]] = 1;
1506                         while ($xoff < $xlim)
1507                         $this->xchanged[$this->xind[$xoff++]] = 1;
1508                 } else {
1509                         // Use the partitions to split this problem into subproblems.
1510                         reset($seps);
1511                         $pt1 = $seps[0];
1512                         while ($pt2 = next($seps)) {
1513                                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
1514                                 $pt1 = $pt2;
1515                         }
1516                 }
1517         }
1518
1519         /* Adjust inserts/deletes of identical lines to join changes
1520          * as much as possible.
1521          *
1522          * We do something when a run of changed lines include a
1523          * line at one end and has an excluded, identical line at the other.
1524          * We are free to choose which identical line is included.
1525          * `compareseq' usually chooses the one at the beginning,
1526          * but usually it is cleaner to consider the following identical line
1527          * to be the "change".
1528          *
1529          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
1530          */
1531         function _shift_boundaries ($lines, &$changed, $other_changed) {
1532                 wfProfileIn( __METHOD__ );
1533                 $i = 0;
1534                 $j = 0;
1535
1536                 USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
1537                 $len = sizeof($lines);
1538                 $other_len = sizeof($other_changed);
1539
1540                 while (1) {
1541                         /*
1542                          * Scan forwards to find beginning of another run of changes.
1543                          * Also keep track of the corresponding point in the other file.
1544                          *
1545                          * Throughout this code, $i and $j are adjusted together so that
1546                          * the first $i elements of $changed and the first $j elements
1547                          * of $other_changed both contain the same number of zeros
1548                          * (unchanged lines).
1549                          * Furthermore, $j is always kept so that $j == $other_len or
1550                          * $other_changed[$j] == false.
1551                          */
1552                         while ($j < $other_len && $other_changed[$j])
1553                         $j++;
1554
1555                         while ($i < $len && ! $changed[$i]) {
1556                                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
1557                                 $i++; $j++;
1558                                 while ($j < $other_len && $other_changed[$j])
1559                                 $j++;
1560                         }
1561
1562                         if ($i == $len)
1563                         break;
1564
1565                         $start = $i;
1566
1567                         // Find the end of this run of changes.
1568                         while (++$i < $len && $changed[$i])
1569                         continue;
1570
1571                         do {
1572                                 /*
1573                                  * Record the length of this run of changes, so that
1574                                  * we can later determine whether the run has grown.
1575                                  */
1576                                 $runlength = $i - $start;
1577
1578                                 /*
1579                                  * Move the changed region back, so long as the
1580                                  * previous unchanged line matches the last changed one.
1581                                  * This merges with previous changed regions.
1582                                  */
1583                                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
1584                                         $changed[--$start] = 1;
1585                                         $changed[--$i] = false;
1586                                         while ($start > 0 && $changed[$start - 1])
1587                                         $start--;
1588                                         USE_ASSERTS && assert('$j > 0');
1589                                         while ($other_changed[--$j])
1590                                         continue;
1591                                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
1592                                 }
1593
1594                                 /*
1595                                  * Set CORRESPONDING to the end of the changed run, at the last
1596                                  * point where it corresponds to a changed run in the other file.
1597                                  * CORRESPONDING == LEN means no such point has been found.
1598                                  */
1599                                 $corresponding = $j < $other_len ? $i : $len;
1600
1601                                 /*
1602                                  * Move the changed region forward, so long as the
1603                                  * first changed line matches the following unchanged one.
1604                                  * This merges with following changed regions.
1605                                  * Do this second, so that if there are no merges,
1606                                  * the changed region is moved forward as far as possible.
1607                                  */
1608                                 while ($i < $len && $lines[$start] == $lines[$i]) {
1609                                         $changed[$start++] = false;
1610                                         $changed[$i++] = 1;
1611                                         while ($i < $len && $changed[$i])
1612                                         $i++;
1613
1614                                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
1615                                         $j++;
1616                                         if ($j < $other_len && $other_changed[$j]) {
1617                                                 $corresponding = $i;
1618                                                 while ($j < $other_len && $other_changed[$j])
1619                                                 $j++;
1620                                         }
1621                                 }
1622                         } while ($runlength != $i - $start);
1623
1624                         /*
1625                          * If possible, move the fully-merged run of changes
1626                          * back to a corresponding run in the other file.
1627                          */
1628                         while ($corresponding < $i) {
1629                                 $changed[--$start] = 1;
1630                                 $changed[--$i] = 0;
1631                                 USE_ASSERTS && assert('$j > 0');
1632                                 while ($other_changed[--$j])
1633                                 continue;
1634                                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
1635                         }
1636                 }
1637                 wfProfileOut( __METHOD__ );
1638         }
1639 }
1640
1641 /**
1642  * Class representing a 'diff' between two sequences of strings.
1643  * @todo document
1644  * @private
1645  * @ingroup DifferenceEngine
1646  */
1647 class Diff
1648 {
1649         var $edits;
1650
1651         /**
1652          * Constructor.
1653          * Computes diff between sequences of strings.
1654          *
1655          * @param $from_lines array An array of strings.
1656          *                (Typically these are lines from a file.)
1657          * @param $to_lines array An array of strings.
1658          */
1659         function Diff($from_lines, $to_lines) {
1660                 $eng = new _DiffEngine;
1661                 $this->edits = $eng->diff($from_lines, $to_lines);
1662                 //$this->_check($from_lines, $to_lines);
1663         }
1664
1665         /**
1666          * Compute reversed Diff.
1667          *
1668          * SYNOPSIS:
1669          *
1670          *      $diff = new Diff($lines1, $lines2);
1671          *      $rev = $diff->reverse();
1672          * @return object A Diff object representing the inverse of the
1673          *                                original diff.
1674          */
1675         function reverse () {
1676                 $rev = $this;
1677                 $rev->edits = array();
1678                 foreach ($this->edits as $edit) {
1679                         $rev->edits[] = $edit->reverse();
1680                 }
1681                 return $rev;
1682         }
1683
1684         /**
1685          * Check for empty diff.
1686          *
1687          * @return bool True iff two sequences were identical.
1688          */
1689         function isEmpty () {
1690                 foreach ($this->edits as $edit) {
1691                         if ($edit->type != 'copy')
1692                         return false;
1693                 }
1694                 return true;
1695         }
1696
1697         /**
1698          * Compute the length of the Longest Common Subsequence (LCS).
1699          *
1700          * This is mostly for diagnostic purposed.
1701          *
1702          * @return int The length of the LCS.
1703          */
1704         function lcs () {
1705                 $lcs = 0;
1706                 foreach ($this->edits as $edit) {
1707                         if ($edit->type == 'copy')
1708                         $lcs += sizeof($edit->orig);
1709                 }
1710                 return $lcs;
1711         }
1712
1713         /**
1714          * Get the original set of lines.
1715          *
1716          * This reconstructs the $from_lines parameter passed to the
1717          * constructor.
1718          *
1719          * @return array The original sequence of strings.
1720          */
1721         function orig() {
1722                 $lines = array();
1723
1724                 foreach ($this->edits as $edit) {
1725                         if ($edit->orig)
1726                         array_splice($lines, sizeof($lines), 0, $edit->orig);
1727                 }
1728                 return $lines;
1729         }
1730
1731         /**
1732          * Get the closing set of lines.
1733          *
1734          * This reconstructs the $to_lines parameter passed to the
1735          * constructor.
1736          *
1737          * @return array The sequence of strings.
1738          */
1739         function closing() {
1740                 $lines = array();
1741
1742                 foreach ($this->edits as $edit) {
1743                         if ($edit->closing)
1744                         array_splice($lines, sizeof($lines), 0, $edit->closing);
1745                 }
1746                 return $lines;
1747         }
1748
1749         /**
1750          * Check a Diff for validity.
1751          *
1752          * This is here only for debugging purposes.
1753          */
1754         function _check ($from_lines, $to_lines) {
1755                 wfProfileIn( __METHOD__ );
1756                 if (serialize($from_lines) != serialize($this->orig()))
1757                 trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
1758                 if (serialize($to_lines) != serialize($this->closing()))
1759                 trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
1760
1761                 $rev = $this->reverse();
1762                 if (serialize($to_lines) != serialize($rev->orig()))
1763                 trigger_error("Reversed original doesn't match", E_USER_ERROR);
1764                 if (serialize($from_lines) != serialize($rev->closing()))
1765                 trigger_error("Reversed closing doesn't match", E_USER_ERROR);
1766
1767
1768                 $prevtype = 'none';
1769                 foreach ($this->edits as $edit) {
1770                         if ( $prevtype == $edit->type )
1771                         trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
1772                         $prevtype = $edit->type;
1773                 }
1774
1775                 $lcs = $this->lcs();
1776                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
1777                 wfProfileOut( __METHOD__ );
1778         }
1779 }
1780
1781 /**
1782  * @todo document, bad name.
1783  * @private
1784  * @ingroup DifferenceEngine
1785  */
1786 class MappedDiff extends Diff
1787 {
1788         /**
1789          * Constructor.
1790          *
1791          * Computes diff between sequences of strings.
1792          *
1793          * This can be used to compute things like
1794          * case-insensitve diffs, or diffs which ignore
1795          * changes in white-space.
1796          *
1797          * @param $from_lines array An array of strings.
1798          *      (Typically these are lines from a file.)
1799          *
1800          * @param $to_lines array An array of strings.
1801          *
1802          * @param $mapped_from_lines array This array should
1803          *      have the same size number of elements as $from_lines.
1804          *      The elements in $mapped_from_lines and
1805          *      $mapped_to_lines are what is actually compared
1806          *      when computing the diff.
1807          *
1808          * @param $mapped_to_lines array This array should
1809          *      have the same number of elements as $to_lines.
1810          */
1811         function MappedDiff($from_lines, $to_lines,
1812         $mapped_from_lines, $mapped_to_lines) {
1813                 wfProfileIn( __METHOD__ );
1814
1815                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
1816                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
1817
1818                 $this->Diff($mapped_from_lines, $mapped_to_lines);
1819
1820                 $xi = $yi = 0;
1821                 for ($i = 0; $i < sizeof($this->edits); $i++) {
1822                         $orig = &$this->edits[$i]->orig;
1823                         if (is_array($orig)) {
1824                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
1825                                 $xi += sizeof($orig);
1826                         }
1827
1828                         $closing = &$this->edits[$i]->closing;
1829                         if (is_array($closing)) {
1830                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
1831                                 $yi += sizeof($closing);
1832                         }
1833                 }
1834                 wfProfileOut( __METHOD__ );
1835         }
1836 }
1837
1838 /**
1839  * A class to format Diffs
1840  *
1841  * This class formats the diff in classic diff format.
1842  * It is intended that this class be customized via inheritance,
1843  * to obtain fancier outputs.
1844  * @todo document
1845  * @private
1846  * @ingroup DifferenceEngine
1847  */
1848 class DiffFormatter {
1849         /**
1850          * Number of leading context "lines" to preserve.
1851          *
1852          * This should be left at zero for this class, but subclasses
1853          * may want to set this to other values.
1854          */
1855         var $leading_context_lines = 0;
1856
1857         /**
1858          * Number of trailing context "lines" to preserve.
1859          *
1860          * This should be left at zero for this class, but subclasses
1861          * may want to set this to other values.
1862          */
1863         var $trailing_context_lines = 0;
1864
1865         /**
1866          * Format a diff.
1867          *
1868          * @param $diff object A Diff object.
1869          * @return string The formatted output.
1870          */
1871         function format($diff) {
1872                 wfProfileIn( __METHOD__ );
1873
1874                 $xi = $yi = 1;
1875                 $block = false;
1876                 $context = array();
1877
1878                 $nlead = $this->leading_context_lines;
1879                 $ntrail = $this->trailing_context_lines;
1880
1881                 $this->_start_diff();
1882
1883                 foreach ($diff->edits as $edit) {
1884                         if ($edit->type == 'copy') {
1885                                 if (is_array($block)) {
1886                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1887                                                 $block[] = $edit;
1888                                         }
1889                                         else{
1890                                                 if ($ntrail) {
1891                                                         $context = array_slice($edit->orig, 0, $ntrail);
1892                                                         $block[] = new _DiffOp_Copy($context);
1893                                                 }
1894                                                 $this->_block($x0, $ntrail + $xi - $x0,
1895                                                 $y0, $ntrail + $yi - $y0,
1896                                                 $block);
1897                                                 $block = false;
1898                                         }
1899                                 }
1900                                 $context = $edit->orig;
1901                         }
1902                         else {
1903                                 if (! is_array($block)) {
1904                                         $context = array_slice($context, sizeof($context) - $nlead);
1905                                         $x0 = $xi - sizeof($context);
1906                                         $y0 = $yi - sizeof($context);
1907                                         $block = array();
1908                                         if ($context)
1909                                         $block[] = new _DiffOp_Copy($context);
1910                                 }
1911                                 $block[] = $edit;
1912                         }
1913
1914                         if ($edit->orig)
1915                         $xi += sizeof($edit->orig);
1916                         if ($edit->closing)
1917                         $yi += sizeof($edit->closing);
1918                 }
1919
1920                 if (is_array($block))
1921                 $this->_block($x0, $xi - $x0,
1922                 $y0, $yi - $y0,
1923                 $block);
1924
1925                 $end = $this->_end_diff();
1926                 wfProfileOut( __METHOD__ );
1927                 return $end;
1928         }
1929
1930         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1931                 wfProfileIn( __METHOD__ );
1932                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1933                 foreach ($edits as $edit) {
1934                         if ($edit->type == 'copy')
1935                         $this->_context($edit->orig);
1936                         elseif ($edit->type == 'add')
1937                         $this->_added($edit->closing);
1938                         elseif ($edit->type == 'delete')
1939                         $this->_deleted($edit->orig);
1940                         elseif ($edit->type == 'change')
1941                         $this->_changed($edit->orig, $edit->closing);
1942                         else
1943                         trigger_error('Unknown edit type', E_USER_ERROR);
1944                 }
1945                 $this->_end_block();
1946                 wfProfileOut( __METHOD__ );
1947         }
1948
1949         function _start_diff() {
1950                 ob_start();
1951         }
1952
1953         function _end_diff() {
1954                 $val = ob_get_contents();
1955                 ob_end_clean();
1956                 return $val;
1957         }
1958
1959         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1960                 if ($xlen > 1)
1961                 $xbeg .= "," . ($xbeg + $xlen - 1);
1962                 if ($ylen > 1)
1963                 $ybeg .= "," . ($ybeg + $ylen - 1);
1964
1965                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1966         }
1967
1968         function _start_block($header) {
1969                 echo $header . "\n";
1970         }
1971
1972         function _end_block() {
1973         }
1974
1975         function _lines($lines, $prefix = ' ') {
1976                 foreach ($lines as $line)
1977                 echo "$prefix $line\n";
1978         }
1979
1980         function _context($lines) {
1981                 $this->_lines($lines);
1982         }
1983
1984         function _added($lines) {
1985                 $this->_lines($lines, '>');
1986         }
1987         function _deleted($lines) {
1988                 $this->_lines($lines, '<');
1989         }
1990
1991         function _changed($orig, $closing) {
1992                 $this->_deleted($orig);
1993                 echo "---\n";
1994                 $this->_added($closing);
1995         }
1996 }
1997
1998 /**
1999  * A formatter that outputs unified diffs
2000  * @ingroup DifferenceEngine
2001  */
2002
2003 class UnifiedDiffFormatter extends DiffFormatter {
2004         var $leading_context_lines = 2;
2005         var $trailing_context_lines = 2;
2006
2007         function _added($lines) {
2008                 $this->_lines($lines, '+');
2009         }
2010         function _deleted($lines) {
2011                 $this->_lines($lines, '-');
2012         }
2013         function _changed($orig, $closing) {
2014                 $this->_deleted($orig);
2015                 $this->_added($closing);
2016         }
2017         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
2018                 return "@@ -$xbeg,$xlen +$ybeg,$ylen @@";
2019         }
2020 }
2021
2022 /**
2023  * A pseudo-formatter that just passes along the Diff::$edits array
2024  * @ingroup DifferenceEngine
2025  */
2026 class ArrayDiffFormatter extends DiffFormatter {
2027         function format($diff) {
2028                 $oldline = 1;
2029                 $newline = 1;
2030                 $retval = array();
2031                 foreach($diff->edits as $edit)
2032                 switch($edit->type) {
2033                         case 'add':
2034                                 foreach($edit->closing as $l) {
2035                                         $retval[] = array(
2036                                                         'action' => 'add',
2037                                                         'new'=> $l,
2038                                                         'newline' => $newline++
2039                                         );
2040                                 }
2041                                 break;
2042                         case 'delete':
2043                                 foreach($edit->orig as $l) {
2044                                         $retval[] = array(
2045                                                         'action' => 'delete',
2046                                                         'old' => $l,
2047                                                         'oldline' => $oldline++,
2048                                         );
2049                                 }
2050                                 break;
2051                         case 'change':
2052                                 foreach($edit->orig as $i => $l) {
2053                                         $retval[] = array(
2054                                                         'action' => 'change',
2055                                                         'old' => $l,
2056                                                         'new' => @$edit->closing[$i],
2057                                                         'oldline' => $oldline++,
2058                                                         'newline' => $newline++,
2059                                         );
2060                                 }
2061                                 break;
2062                         case 'copy':
2063                                 $oldline += count($edit->orig);
2064                                 $newline += count($edit->orig);
2065                 }
2066                 return $retval;
2067         }
2068 }
2069
2070 /**
2071  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
2072  *
2073  */
2074
2075 define('NBSP', '&#160;'); // iso-8859-x non-breaking space.
2076
2077 /**
2078  * @todo document
2079  * @private
2080  * @ingroup DifferenceEngine
2081  */
2082 class _HWLDF_WordAccumulator {
2083         function _HWLDF_WordAccumulator () {
2084                 $this->_lines = array();
2085                 $this->_line = '';
2086                 $this->_group = '';
2087                 $this->_tag = '';
2088         }
2089
2090         function _flushGroup ($new_tag) {
2091                 if ($this->_group !== '') {
2092                         if ($this->_tag == 'ins')
2093                         $this->_line .= '<ins class="diffchange diffchange-inline">' .
2094                         htmlspecialchars ( $this->_group ) . '</ins>';
2095                         elseif ($this->_tag == 'del')
2096                         $this->_line .= '<del class="diffchange diffchange-inline">' .
2097                         htmlspecialchars ( $this->_group ) . '</del>';
2098                         else
2099                         $this->_line .= htmlspecialchars ( $this->_group );
2100                 }
2101                 $this->_group = '';
2102                 $this->_tag = $new_tag;
2103         }
2104
2105         function _flushLine ($new_tag) {
2106                 $this->_flushGroup($new_tag);
2107                 if ($this->_line != '')
2108                 array_push ( $this->_lines, $this->_line );
2109                 else
2110                 # make empty lines visible by inserting an NBSP
2111                 array_push ( $this->_lines, NBSP );
2112                 $this->_line = '';
2113         }
2114
2115         function addWords ($words, $tag = '') {
2116                 if ($tag != $this->_tag)
2117                 $this->_flushGroup($tag);
2118
2119                 foreach ($words as $word) {
2120                         // new-line should only come as first char of word.
2121                         if ($word == '')
2122                         continue;
2123                         if ($word[0] == "\n") {
2124                                 $this->_flushLine($tag);
2125                                 $word = substr($word, 1);
2126                         }
2127                         assert(!strstr($word, "\n"));
2128                         $this->_group .= $word;
2129                 }
2130         }
2131
2132         function getLines() {
2133                 $this->_flushLine('~done');
2134                 return $this->_lines;
2135         }
2136 }
2137
2138 /**
2139  * @todo document
2140  * @private
2141  * @ingroup DifferenceEngine
2142  */
2143 class WordLevelDiff extends MappedDiff {
2144         const MAX_LINE_LENGTH = 10000;
2145
2146         function WordLevelDiff ($orig_lines, $closing_lines) {
2147                 wfProfileIn( __METHOD__ );
2148
2149                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
2150                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
2151
2152                 $this->MappedDiff($orig_words, $closing_words,
2153                 $orig_stripped, $closing_stripped);
2154                 wfProfileOut( __METHOD__ );
2155         }
2156
2157         function _split($lines) {
2158                 wfProfileIn( __METHOD__ );
2159
2160                 $words = array();
2161                 $stripped = array();
2162                 $first = true;
2163                 foreach ( $lines as $line ) {
2164                         # If the line is too long, just pretend the entire line is one big word
2165                         # This prevents resource exhaustion problems
2166                         if ( $first ) {
2167                                 $first = false;
2168                         } else {
2169                                 $words[] = "\n";
2170                                 $stripped[] = "\n";
2171                         }
2172                         if ( strlen( $line ) > self::MAX_LINE_LENGTH ) {
2173                                 $words[] = $line;
2174                                 $stripped[] = $line;
2175                         } else {
2176                                 $m = array();
2177                                 if (preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
2178                                 $line, $m))
2179                                 {
2180                                         $words = array_merge( $words, $m[0] );
2181                                         $stripped = array_merge( $stripped, $m[1] );
2182                                 }
2183                         }
2184                 }
2185                 wfProfileOut( __METHOD__ );
2186                 return array($words, $stripped);
2187         }
2188
2189         function orig () {
2190                 wfProfileIn( __METHOD__ );
2191                 $orig = new _HWLDF_WordAccumulator;
2192
2193                 foreach ($this->edits as $edit) {
2194                         if ($edit->type == 'copy')
2195                         $orig->addWords($edit->orig);
2196                         elseif ($edit->orig)
2197                         $orig->addWords($edit->orig, 'del');
2198                 }
2199                 $lines = $orig->getLines();
2200                 wfProfileOut( __METHOD__ );
2201                 return $lines;
2202         }
2203
2204         function closing () {
2205                 wfProfileIn( __METHOD__ );
2206                 $closing = new _HWLDF_WordAccumulator;
2207
2208                 foreach ($this->edits as $edit) {
2209                         if ($edit->type == 'copy')
2210                         $closing->addWords($edit->closing);
2211                         elseif ($edit->closing)
2212                         $closing->addWords($edit->closing, 'ins');
2213                 }
2214                 $lines = $closing->getLines();
2215                 wfProfileOut( __METHOD__ );
2216                 return $lines;
2217         }
2218 }
2219
2220 /**
2221  * Wikipedia Table style diff formatter.
2222  * @todo document
2223  * @private
2224  * @ingroup DifferenceEngine
2225  */
2226 class TableDiffFormatter extends DiffFormatter {
2227         function TableDiffFormatter() {
2228                 $this->leading_context_lines = 2;
2229                 $this->trailing_context_lines = 2;
2230         }
2231
2232         public static function escapeWhiteSpace( $msg ) {
2233                 $msg = preg_replace( '/^ /m', '&nbsp; ', $msg );
2234                 $msg = preg_replace( '/ $/m', ' &nbsp;', $msg );
2235                 $msg = preg_replace( '/  /', '&nbsp; ', $msg );
2236                 return $msg;
2237         }
2238
2239         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
2240                 $r = '<tr><td colspan="2" class="diff-lineno"><!--LINE '.$xbeg."--></td>\n" .
2241                   '<td colspan="2" class="diff-lineno"><!--LINE '.$ybeg."--></td></tr>\n";
2242                 return $r;
2243         }
2244
2245         function _start_block( $header ) {
2246                 echo $header;
2247         }
2248
2249         function _end_block() {
2250         }
2251
2252         function _lines( $lines, $prefix=' ', $color='white' ) {
2253         }
2254
2255         # HTML-escape parameter before calling this
2256         function addedLine( $line ) {
2257                 return $this->wrapLine( '+', 'diff-addedline', $line );
2258         }
2259
2260         # HTML-escape parameter before calling this
2261         function deletedLine( $line ) {
2262                 return $this->wrapLine( '-', 'diff-deletedline', $line );
2263         }
2264
2265         # HTML-escape parameter before calling this
2266         function contextLine( $line ) {
2267                 return $this->wrapLine( ' ', 'diff-context', $line );
2268         }
2269
2270         private function wrapLine( $marker, $class, $line ) {
2271                 if( $line !== '' ) {
2272                         // The <div> wrapper is needed for 'overflow: auto' style to scroll properly
2273                         $line = Xml::tags( 'div', null, $this->escapeWhiteSpace( $line ) );
2274                 }
2275                 return "<td class='diff-marker'>$marker</td><td class='$class'>$line</td>";
2276         }
2277
2278         function emptyLine() {
2279                 return '<td colspan="2">&nbsp;</td>';
2280         }
2281
2282         function _added( $lines ) {
2283                 foreach ($lines as $line) {
2284                         echo '<tr>' . $this->emptyLine() .
2285                         $this->addedLine( '<ins class="diffchange">' .
2286                         htmlspecialchars ( $line ) . '</ins>' ) . "</tr>\n";
2287                 }
2288         }
2289
2290         function _deleted($lines) {
2291                 foreach ($lines as $line) {
2292                         echo '<tr>' . $this->deletedLine( '<del class="diffchange">' .
2293                         htmlspecialchars ( $line ) . '</del>' ) .
2294                         $this->emptyLine() . "</tr>\n";
2295                 }
2296         }
2297
2298         function _context( $lines ) {
2299                 foreach ($lines as $line) {
2300                         echo '<tr>' .
2301                         $this->contextLine( htmlspecialchars ( $line ) ) .
2302                         $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
2303                 }
2304         }
2305
2306         function _changed( $orig, $closing ) {
2307                 wfProfileIn( __METHOD__ );
2308
2309                 $diff = new WordLevelDiff( $orig, $closing );
2310                 $del = $diff->orig();
2311                 $add = $diff->closing();
2312
2313                 # Notice that WordLevelDiff returns HTML-escaped output.
2314                 # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
2315
2316                 while ( $line = array_shift( $del ) ) {
2317                         $aline = array_shift( $add );
2318                         echo '<tr>' . $this->deletedLine( $line ) .
2319                         $this->addedLine( $aline ) . "</tr>\n";
2320                 }
2321                 foreach ($add as $line) {       # If any leftovers
2322                         echo '<tr>' . $this->emptyLine() .
2323                         $this->addedLine( $line ) . "</tr>\n";
2324                 }
2325                 wfProfileOut( __METHOD__ );
2326         }
2327 }