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