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