includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * @defgroup DifferenceEngine DifferenceEngine
   4  */
   5
   6 /**
   7  * Constant to indicate diff cache compatibility.
   8  * Bump this when changing the diff formatting in a way that
   9  * fixes important bugs or such to force cached diff views to
  10  * clear.
  11  */
  12 define( 'MW_DIFF_VERSION', '1.11a' );
  13
  14 /**
  15  * @todo document
  16  * @ingroup DifferenceEngine
  17  */
  18 class DifferenceEngine {
  19         /**#@+
  20          * @private
  21          */
  22         var $mOldid, $mNewid, $mTitle;
  23         var $mOldtitle, $mNewtitle, $mPagetitle;
  24         var $mOldtext, $mNewtext;
  25         var $mOldPage, $mNewPage;
  26         var $mRcidMarkPatrolled;
  27         var $mOldRev, $mNewRev;
  28         var $mRevisionsLoaded = false; // Have the revisions been loaded
  29         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  30         var $mCacheHit = false; // Was the diff fetched from cache?
  31         var $htmldiff;
  32
  33         protected $unhide = false;
  34         /**#@-*/
  35
  36         /**
  37          * Constructor
  38          * @param $titleObj Title object that the diff is associated with
  39          * @param $old Integer: old ID we want to show and diff with.
  40          * @param $new String: either 'prev' or 'next'.
  41          * @param $rcid Integer: ??? FIXME (default 0)
  42          * @param $refreshCache boolean If set, refreshes the diff cache
  43          * @param $htmldiff boolean If set, output using HTMLDiff instead of raw wikicode diff
  44          * @param $unhide boolean If set, allow viewing deleted revs
  45          */
  46         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  47                 $refreshCache = false, $htmldiff = false, $unhide = false )
  48         {
  49                 if ( $titleObj ) {
  50                         $this->mTitle = $titleObj;
  51                 } else {
  52                         global $wgTitle;
  53                         $this->mTitle = $wgTitle;
  54                 }
  55                 wfDebug("DifferenceEngine old '$old' new '$new' rcid '$rcid'\n");
  56
  57                 if ( 'prev' === $new ) {
  58                         # Show diff between revision $old and the previous one.
  59                         # Get previous one from DB.
  60                         $this->mNewid = intval($old);
  61                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  62                 } elseif ( 'next' === $new ) {
  63                         # Show diff between revision $old and the next one.
  64                         # Get next one from DB.
  65                         $this->mOldid = intval($old);
  66                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  67                         if ( false === $this->mNewid ) {
  68                                 # if no result, NewId points to the newest old revision. The only newer
  69                                 # revision is cur, which is "0".
  70                                 $this->mNewid = 0;
  71                         }
  72                 } else {
  73                         $this->mOldid = intval($old);
  74                         $this->mNewid = intval($new);
  75                         wfRunHooks( 'NewDifferenceEngine', array(&$titleObj, &$this->mOldid, &$this->mNewid, $old, $new) );
  76                 }
  77                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  78                 $this->mRefreshCache = $refreshCache;
  79                 $this->htmldiff = $htmldiff;
  80                 $this->unhide = $unhide;
  81         }
  82
  83         function getTitle() {
  84                 return $this->mTitle;
  85         }
  86
  87         function wasCacheHit() {
  88                 return $this->mCacheHit;
  89         }
  90
  91         function getOldid() {
  92                 return $this->mOldid;
  93         }
  94
  95         function getNewid() {
  96                 return $this->mNewid;
  97         }
  98
  99         function showDiffPage( $diffOnly = false ) {
 100                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol, $wgEnableHtmlDiff;
 101                 wfProfileIn( __METHOD__ );
 102
 103
 104                 # If external diffs are enabled both globally and for the user,
 105                 # we'll use the application/x-external-editor interface to call
 106                 # an external diff tool like kompare, kdiff3, etc.
 107                 if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
 108                         global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
 109                         $wgOut->disable();
 110                         header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
 111                         $url1=$this->mTitle->getFullURL( array(
 112                                 'action' => 'raw',
 113                                 'oldid' => $this->mOldid
 114                         ) );
 115                         $url2=$this->mTitle->getFullURL( array(
 116                                 'action' => 'raw',
 117                                 'oldid' => $this->mNewid
 118                         ) );
 119                         $special=$wgLang->getNsText(NS_SPECIAL);
 120                         $control=<<<CONTROL
 121                         [Process]
 122                         Type=Diff text
 123                         Engine=MediaWiki
 124                         Script={$wgServer}{$wgScript}
 125                         Special namespace={$special}
 126
 127                         [File]
 128                         Extension=wiki
 129                         URL=$url1
 130
 131                         [File 2]
 132                         Extension=wiki
 133                         URL=$url2
 134 CONTROL;
 135                         echo($control);
 136                         return;
 137                 }
 138
 139                 $wgOut->setArticleFlag( false );
 140                 if ( !$this->loadRevisionData() ) {
 141                         $t = $this->mTitle->getPrefixedText();
 142                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 143                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 144                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 145                         wfProfileOut( __METHOD__ );
 146                         return;
 147                 }
 148
 149                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 150
 151                 if ( $this->mNewRev->isCurrent() ) {
 152                         $wgOut->setArticleFlag( true );
 153                 }
 154
 155                 # mOldid is false if the difference engine is called with a "vague" query for
 156                 # a diff between a version V and its previous version V' AND the version V
 157                 # is the first version of that article. In that case, V' does not exist.
 158                 if ( $this->mOldid === false ) {
 159                         $this->showFirstRevision();
 160                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 161                         wfProfileOut( __METHOD__ );
 162                         return;
 163                 }
 164
 165                 $wgOut->suppressQuickbar();
 166
 167                 $oldTitle = $this->mOldPage->getPrefixedText();
 168                 $newTitle = $this->mNewPage->getPrefixedText();
 169                 if( $oldTitle == $newTitle ) {
 170                         $wgOut->setPageTitle( $newTitle );
 171                 } else {
 172                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 173                 }
 174                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 175                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 176
 177                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 178                         $wgOut->loginToUse();
 179                         $wgOut->output();
 180                         $wgOut->disable();
 181                         wfProfileOut( __METHOD__ );
 182                         return;
 183                 }
 184
 185                 $sk = $wgUser->getSkin();
 186
 187                 // Check if page is editable
 188                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 189                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 190                         $rollback = '&nbsp;&nbsp;&nbsp;' . $sk->generateRollback( $this->mNewRev );
 191                 } else {
 192                         $rollback = '';
 193                 }
 194
 195                 // Prepare a change patrol link, if applicable
 196                 if( $wgUseRCPatrol && $this->mTitle->userCan('patrol') ) {
 197                         // If we've been given an explicit change identifier, use it; saves time
 198                         if( $this->mRcidMarkPatrolled ) {
 199                                 $rcid = $this->mRcidMarkPatrolled;
 200                                 $rc = RecentChange::newFromId( $rcid );
 201                                 // Already patrolled?
 202                                 $rcid = is_object($rc) && !$rc->getAttribute('rc_patrolled') ? $rcid : 0;
 203                         } else {
 204                                 // Look for an unpatrolled change corresponding to this diff
 205                                 $db = wfGetDB( DB_SLAVE );
 206                                 $change = RecentChange::newFromConds(
 207                                         array(
 208                                         // Redundant user,timestamp condition so we can use the existing index
 209                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 210                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 211                                                 'rc_this_oldid' => $this->mNewid,
 212                                                 'rc_last_oldid' => $this->mOldid,
 213                                                 'rc_patrolled'  => 0
 214                                         ),
 215                                         __METHOD__
 216                                 );
 217                                 if( $change instanceof RecentChange ) {
 218                                         $rcid = $change->mAttribs['rc_id'];
 219                                         $this->mRcidMarkPatrolled = $rcid;
 220                                 } else {
 221                                         // None found
 222                                         $rcid = 0;
 223                                 }
 224                         }
 225                         // Build the link
 226                         if( $rcid ) {
 227                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 228                                         $this->mTitle,
 229                                         wfMsgHtml( 'markaspatrolleddiff' ),
 230                                         array(),
 231                                         array(
 232                                                 'action' => 'markpatrolled',
 233                                                 'rcid' => $rcid
 234                                         ),
 235                                         array(
 236                                                 'known',
 237                                                 'noclasses'
 238                                         )
 239                                 ) . ']</span>';
 240                         } else {
 241                                 $patrol = '';
 242                         }
 243                 } else {
 244                         $patrol = '';
 245                 }
 246
 247                 # Carry over 'diffonly' param via navigation links
 248                 if( $diffOnly != $wgUser->getBoolOption('diffonly') ) {
 249                         $query['diffonly'] = $diffOnly;
 250                 }
 251
 252                 $htmldiffarg = $this->htmlDiffArgument();
 253
 254                 if( $htmldiffarg ) {
 255                         $query['htmldiff'] = $htmldiffarg['htmldiff'];
 256                 }
 257
 258                 # Make "previous revision link"
 259                 $query['diff'] = 'prev';
 260                 $query['oldid'] = $this->mOldid;
 261
 262                 $prevlink = $sk->link(
 263                         $this->mTitle,
 264                         wfMsgHtml( 'previousdiff' ),
 265                         array(
 266                                 'id' => 'differences-prevlink'
 267                         ),
 268                         $query,
 269                         array(
 270                                 'known',
 271                                 'noclasses'
 272                         )
 273                 );
 274                 # Make "next revision link"
 275                 $query['diff'] = 'next';
 276                 $query['oldid'] = $this->mNewid;
 277
 278                 if( $this->mNewRev->isCurrent() ) {
 279                         $nextlink = '&nbsp;';
 280                 } else {
 281                         $nextlink = $sk->link(
 282                                 $this->mTitle,
 283                                 wfMsgHtml( 'nextdiff' ),
 284                                 array(
 285                                         'id' => 'differences-nextlink'
 286                                 ),
 287                                 $query,
 288                                 array(
 289                                         'known',
 290                                         'noclasses'
 291                                 )
 292                         );
 293                 }
 294
 295                 $oldminor = '';
 296                 $newminor = '';
 297
 298                 if( $this->mOldRev->isMinor() ) {
 299                         $oldminor = Xml::span( wfMsg( 'minoreditletter' ), 'minor' ) . ' ';
 300                 }
 301                 if( $this->mNewRev->isMinor() ) {
 302                         $newminor = Xml::span( wfMsg( 'minoreditletter' ), 'minor' ) . ' ';
 303                 }
 304
 305                 $rdel = ''; $ldel = '';
 306                 if( $wgUser->isAllowed( 'deleterevision' ) ) {
 307                         if( !$this->mOldRev->userCan( Revision::DELETED_RESTRICTED ) ) {
 308                                 // If revision was hidden from sysops
 309                                 $ldel = Xml::tags( 'span', array( 'class' => 'mw-revdelundel-link' ), '(' . wfMsgHtml( 'rev-delundel' ) . ')' );
 310                         } else {
 311                                 $query = array(
 312                                         'type' => 'revision',
 313                                         'target' => $this->mOldRev->mTitle->getPrefixedDbkey(),
 314                                         'ids' => $this->mOldRev->getId()
 315                                 );
 316                                 $ldel = $sk->revDeleteLink( $query, $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) );
 317                         }
 318                         $ldel = "&nbsp;&nbsp;&nbsp;$ldel ";
 319                         // We don't currently handle well changing the top revision's settings
 320                         if( $this->mNewRev->isCurrent() ) {
 321                                 $rdel = Xml::tags( 'span', array( 'class'=>'mw-revdelundel-link' ), '('.wfMsgHtml( 'rev-delundel' ).')' );
 322                         } else if( !$this->mNewRev->userCan( Revision::DELETED_RESTRICTED ) ) {
 323                                 // If revision was hidden from sysops
 324                                 $rdel = Xml::tags( 'span', array( 'class'=>'mw-revdelundel-link' ), '('.wfMsgHtml( 'rev-delundel' ).')' );
 325                         } else {
 326                                 $query = array(
 327                                         'type' => 'revision',
 328                                         'target' =>  $this->mNewRev->mTitle->getPrefixedDbkey(),
 329                                         'ids' => $this->mNewRev->getId()
 330                                 );
 331                                 $rdel = $sk->revDeleteLink( $query, $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) );
 332                         }
 333                         $rdel = "&nbsp;&nbsp;&nbsp;$rdel ";
 334                 }
 335
 336                 $oldHeader = '<div id="mw-diff-otitle1"><strong>'.$this->mOldtitle.'</strong></div>' .
 337                         '<div id="mw-diff-otitle2">' . $sk->revUserTools( $this->mOldRev, !$this->unhide ) . "</div>" .
 338                         '<div id="mw-diff-otitle3">' . $oldminor . $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ).$ldel."</div>" .
 339                         '<div id="mw-diff-otitle4">' . $prevlink .'</div>';
 340                 $newHeader = '<div id="mw-diff-ntitle1"><strong>'.$this->mNewtitle.'</strong></div>' .
 341                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) . " $rollback</div>" .
 342                         '<div id="mw-diff-ntitle3">' . $newminor . $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ).$rdel."</div>" .
 343                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 344
 345                 # Check if this user can see the revisions
 346                 $allowed = $this->mOldRev->userCan(Revision::DELETED_TEXT)
 347                         && $this->mNewRev->userCan(Revision::DELETED_TEXT);
 348                 $deleted = $this->mOldRev->isDeleted(Revision::DELETED_TEXT)
 349                         || $this->mNewRev->isDeleted(Revision::DELETED_TEXT);
 350                 # Output the diff if allowed...
 351                 if( $deleted && (!$this->unhide || !$allowed) ) {
 352                         $this->showDiffStyle();
 353                         $multi = $this->getMultiNotice();
 354                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 355                         if( !$allowed ) {
 356                                 # Give explanation for why revision is not visible
 357                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n",
 358                                         array( 'rev-deleted-no-diff' ) );
 359                         } else {
 360                                 # Give explanation and add a link to view the diff...
 361                                 $link = $this->mTitle->getFullUrl( array(
 362                                         'diff' => $this->mNewid,
 363                                         'oldid' => $this->mOldid,
 364                                         'unhide' => 1
 365                                 ) );
 366                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n",
 367                                         array( 'rev-deleted-unhide-diff', $link ) );
 368                         }
 369                 } else if( $wgEnableHtmlDiff && $this->htmldiff ) {
 370                         $multi = $this->getMultiNotice();
 371                         $wgOut->addHTML( '<div class="diff-switchtype">' . $sk->link(
 372                                 $this->mTitle,
 373                                 wfMsgHtml( 'wikicodecomparison' ),
 374                                 array(
 375                                         'id' => 'differences-switchtype'
 376                                 ),
 377                                 array(
 378                                         'diff' => $this->mNewid,
 379                                         'oldid' => $this->mOldid,
 380                                         'htmldiff' => 0
 381                                 ),
 382                                 array(
 383                                         'known',
 384                                         'noclasses'
 385                                 )
 386                         ) . '</div>');
 387                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 388                         $this->renderHtmlDiff();
 389                 } else {
 390                         if( $wgEnableHtmlDiff ) {
 391                                 $wgOut->addHTML( '<div class="diff-switchtype">' . $sk->link(
 392                                         $this->mTitle,
 393                                         wfMsgHtml( 'visualcomparison' ),
 394                                         array(
 395                                                 'id' => 'differences-switchtype'
 396                                         ),
 397                                         array(
 398                                                 'diff' => $this->mNewid,
 399                                                 'oldid' => $this->mOldid,
 400                                                 'htmldiff' => 1
 401                                         ),
 402                                         array(
 403                                                 'known',
 404                                                 'noclasses'
 405                                         )
 406                                 ) . '</div>');
 407                         }
 408                         $this->showDiff( $oldHeader, $newHeader );
 409                         if( !$diffOnly ) {
 410                                 $this->renderNewRevision();
 411                         }
 412                 }
 413                 wfProfileOut( __METHOD__ );
 414         }
 415
 416         /**
 417          * Show the new revision of the page.
 418          */
 419         function renderNewRevision() {
 420                 global $wgOut, $wgUser;
 421                 wfProfileIn( __METHOD__ );
 422
 423                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 424                 # Add deleted rev tag if needed
 425                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 426                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-permission' );
 427                 } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 428                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-view' );
 429                 }
 430
 431                 if( !$this->mNewRev->isCurrent() ) {
 432                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 433                 }
 434
 435                 $this->loadNewText();
 436                 if( is_object( $this->mNewRev ) ) {
 437                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 438                 }
 439
 440                 if( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 441                         // Stolen from Article::view --AG 2007-10-11
 442                         // Give hooks a chance to customise the output
 443                         if( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 444                                 // Wrap the whole lot in a <pre> and don't parse
 445                                 $m = array();
 446                                 preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 447                                 $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 448                                 $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 449                                 $wgOut->addHTML( "\n</pre>\n" );
 450                         }
 451                 } else {
 452                         $wgOut->addWikiTextTidy( $this->mNewtext );
 453                 }
 454
 455                 if( is_object( $this->mNewRev ) && !$this->mNewRev->isCurrent() ) {
 456                         $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 457                 }
 458                 # Add redundant patrol link on bottom...
 459                 if( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan('patrol') ) {
 460                         $sk = $wgUser->getSkin();
 461                         $wgOut->addHTML(
 462                                 "<div class='patrollink'>[" . $sk->link(
 463                                         $this->mTitle,
 464                                         wfMsgHtml( 'markaspatrolleddiff' ),
 465                                         array(),
 466                                         array(
 467                                                 'action' => 'markpatrolled',
 468                                                 'rcid' => $this->mRcidMarkPatrolled
 469                                         )
 470                                 ) . ']</div>'
 471                          );
 472                 }
 473
 474                 wfProfileOut( __METHOD__ );
 475         }
 476
 477
 478         function renderHtmlDiff() {
 479                 global $wgOut, $wgParser, $wgDebugComments;
 480                 wfProfileIn( __METHOD__ );
 481
 482                 $this->showDiffStyle();
 483
 484                 $wgOut->addHTML( '<h2>'.wfMsgHtml( 'visual-comparison' )."</h2>\n" );
 485                 #add deleted rev tag if needed
 486                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 487                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-permission' );
 488                 } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 489                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1</div>\n", 'rev-deleted-text-view' );
 490                 }
 491
 492                 if( !$this->mNewRev->isCurrent() ) {
 493                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 494                 }
 495
 496                 $this->loadText();
 497
 498                 // Old revision
 499                 if( is_object( $this->mOldRev ) ) {
 500                         $wgOut->setRevisionId( $this->mOldRev->getId() );
 501                 }
 502
 503                 $popts = $wgOut->parserOptions();
 504                 $oldTidy = $popts->setTidy( true );
 505                 $popts->setEditSection( false );
 506
 507                 $parserOutput = $wgParser->parse( $this->mOldtext, $this->getTitle(), $popts, true, true, $wgOut->getRevisionId() );
 508                 $popts->setTidy( $oldTidy );
 509
 510                 //only for new?
 511                 //$wgOut->addParserOutputNoText( $parserOutput );
 512                 $oldHtml = $parserOutput->getText();
 513                 wfRunHooks( 'OutputPageBeforeHTML', array( &$wgOut, &$oldHtml ) );
 514
 515                 // New revision
 516                 if( is_object( $this->mNewRev ) ) {
 517                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 518                 }
 519
 520                 $popts = $wgOut->parserOptions();
 521                 $oldTidy = $popts->setTidy( true );
 522
 523                 $parserOutput = $wgParser->parse( $this->mNewtext, $this->getTitle(), $popts, true, true, $wgOut->getRevisionId() );
 524                 $popts->setTidy( $oldTidy );
 525
 526                 $wgOut->addParserOutputNoText( $parserOutput );
 527                 $newHtml = $parserOutput->getText();
 528                 wfRunHooks( 'OutputPageBeforeHTML', array( &$wgOut, &$newHtml ) );
 529
 530                 unset($parserOutput, $popts);
 531
 532                 $differ = new HTMLDiffer(new DelegatingContentHandler($wgOut));
 533                 $differ->htmlDiff($oldHtml, $newHtml);
 534                 if ( $wgDebugComments ) {
 535                         $wgOut->addHTML( "\n<!-- HtmlDiff Debug Output:\n" . HTMLDiffer::getDebugOutput() . " End Debug -->" );
 536                 }
 537
 538                 wfProfileOut( __METHOD__ );
 539         }
 540
 541         /**
 542          * Show the first revision of an article. Uses normal diff headers in
 543          * contrast to normal "old revision" display style.
 544          */
 545         function showFirstRevision() {
 546                 global $wgOut, $wgUser;
 547                 wfProfileIn( __METHOD__ );
 548
 549                 # Get article text from the DB
 550                 #
 551                 if ( ! $this->loadNewText() ) {
 552                         $t = $this->mTitle->getPrefixedText();
 553                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 554                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 555                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 556                         wfProfileOut( __METHOD__ );
 557                         return;
 558                 }
 559                 if ( $this->mNewRev->isCurrent() ) {
 560                         $wgOut->setArticleFlag( true );
 561                 }
 562
 563                 # Check if user is allowed to look at this page. If not, bail out.
 564                 #
 565                 if ( !$this->mTitle->userCanRead() ) {
 566                         $wgOut->loginToUse();
 567                         $wgOut->output();
 568                         wfProfileOut( __METHOD__ );
 569                         throw new MWException("Permission Error: you do not have access to view this page");
 570                 }
 571
 572                 # Prepare the header box
 573                 #
 574                 $sk = $wgUser->getSkin();
 575
 576                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 577                 if( !$next ) {
 578                         $nextlink = '';
 579                 } else {
 580                         $nextlink = '<br/>' . $sk->link(
 581                                 $this->mTitle,
 582                                 wfMsgHtml( 'nextdiff' ),
 583                                 array(
 584                                         'id' => 'differences-nextlink'
 585                                 ),
 586                                 array(
 587                                         'diff' => 'next',
 588                                         'oldid' => $this->mNewid,
 589                                         $this->htmlDiffArgument()
 590                                 ),
 591                                 array(
 592                                         'known',
 593                                         'noclasses'
 594                                 )
 595                         );
 596                 }
 597                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 598                         $sk->revUserTools( $this->mNewRev ) . "<br/>" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 599
 600                 $wgOut->addHTML( $header );
 601
 602                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 603                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 604
 605                 wfProfileOut( __METHOD__ );
 606         }
 607
 608         function htmlDiffArgument(){
 609                 global $wgEnableHtmlDiff;
 610                 if($wgEnableHtmlDiff){
 611                         if($this->htmldiff){
 612                                 return array( 'htmldiff' => 1 );
 613                         }else{
 614                                 return array( 'htmldiff' => 0 );
 615                         }
 616                 }else{
 617                         return array();
 618                 }
 619         }
 620
 621         /**
 622          * Get the diff text, send it to $wgOut
 623          * Returns false if the diff could not be generated, otherwise returns true
 624          */
 625         function showDiff( $otitle, $ntitle ) {
 626                 global $wgOut;
 627                 $diff = $this->getDiff( $otitle, $ntitle );
 628                 if ( $diff === false ) {
 629                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 630                         return false;
 631                 } else {
 632                         $this->showDiffStyle();
 633                         $wgOut->addHTML( $diff );
 634                         return true;
 635                 }
 636         }
 637
 638         /**
 639          * Add style sheets and supporting JS for diff display.
 640          */
 641         function showDiffStyle() {
 642                 global $wgStylePath, $wgStyleVersion, $wgOut;
 643                 $wgOut->addStyle( 'common/diff.css' );
 644
 645                 // JS is needed to detect old versions of Mozilla to work around an annoyance bug.
 646                 $wgOut->addScript( "<script type=\"text/javascript\" src=\"$wgStylePath/common/diff.js?$wgStyleVersion\"></script>" );
 647         }
 648
 649         /**
 650          * Get complete diff table, including header
 651          *
 652          * @param Title $otitle Old title
 653          * @param Title $ntitle New title
 654          * @return mixed
 655          */
 656         function getDiff( $otitle, $ntitle ) {
 657                 $body = $this->getDiffBody();
 658                 if ( $body === false ) {
 659                         return false;
 660                 } else {
 661                         $multi = $this->getMultiNotice();
 662                         return $this->addHeader( $body, $otitle, $ntitle, $multi );
 663                 }
 664         }
 665
 666         /**
 667          * Get the diff table body, without header
 668          *
 669          * @return mixed
 670          */
 671         function getDiffBody() {
 672                 global $wgMemc;
 673                 wfProfileIn( __METHOD__ );
 674                 $this->mCacheHit = true;
 675                 // Check if the diff should be hidden from this user
 676                 if ( !$this->loadRevisionData() )
 677                         return '';
 678                 if ( $this->mOldRev && !$this->mOldRev->userCan(Revision::DELETED_TEXT) ) {
 679                         return '';
 680                 } else if ( $this->mNewRev && !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 681                         return '';
 682                 } else if ( $this->mOldRev && $this->mNewRev && $this->mOldRev->getID() == $this->mNewRev->getID() ) {
 683                         return '';
 684                 }
 685                 // Cacheable?
 686                 $key = false;
 687                 if ( $this->mOldid && $this->mNewid ) {
 688                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION, 'oldid', $this->mOldid, 'newid', $this->mNewid );
 689                         // Try cache
 690                         if ( !$this->mRefreshCache ) {
 691                                 $difftext = $wgMemc->get( $key );
 692                                 if ( $difftext ) {
 693                                         wfIncrStats( 'diff_cache_hit' );
 694                                         $difftext = $this->localiseLineNumbers( $difftext );
 695                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 696                                         wfProfileOut( __METHOD__ );
 697                                         return $difftext;
 698                                 }
 699                         } // don't try to load but save the result
 700                 }
 701                 $this->mCacheHit = false;
 702
 703                 // Loadtext is permission safe, this just clears out the diff
 704                 if ( !$this->loadText() ) {
 705                         wfProfileOut( __METHOD__ );
 706                         return false;
 707                 }
 708
 709                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 710
 711                 // Save to cache for 7 days
 712                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 713                         wfIncrStats( 'diff_uncacheable' );
 714                 } else if ( $key !== false && $difftext !== false ) {
 715                         wfIncrStats( 'diff_cache_miss' );
 716                         $wgMemc->set( $key, $difftext, 7*86400 );
 717                 } else {
 718                         wfIncrStats( 'diff_uncacheable' );
 719                 }
 720                 // Replace line numbers with the text in the user's language
 721                 if ( $difftext !== false ) {
 722                         $difftext = $this->localiseLineNumbers( $difftext );
 723                 }
 724                 wfProfileOut( __METHOD__ );
 725                 return $difftext;
 726         }
 727
 728         /**
 729          * Make sure the proper modules are loaded before we try to
 730          * make the diff
 731          */
 732         private function initDiffEngines() {
 733                 global $wgExternalDiffEngine;
 734                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 735                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 736                         wfSuppressWarnings();
 737                         dl( 'php_wikidiff.so' );
 738                         wfRestoreWarnings();
 739                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 740                 }
 741                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 742                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 743                         wfSuppressWarnings();
 744                         dl( 'php_wikidiff2.so' );
 745                         wfRestoreWarnings();
 746                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 747                 }
 748         }
 749
 750         /**
 751          * Generate a diff, no caching
 752          * $otext and $ntext must be already segmented
 753          */
 754         function generateDiffBody( $otext, $ntext ) {
 755                 global $wgExternalDiffEngine, $wgContLang;
 756
 757                 $otext = str_replace( "\r\n", "\n", $otext );
 758                 $ntext = str_replace( "\r\n", "\n", $ntext );
 759
 760                 $this->initDiffEngines();
 761
 762                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 763                         # For historical reasons, external diff engine expects
 764                         # input text to be HTML-escaped already
 765                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 766                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 767                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 768                         $this->debug( 'wikidiff1' );
 769                 }
 770
 771                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 772                         # Better external diff engine, the 2 may some day be dropped
 773                         # This one does the escaping and segmenting itself
 774                         wfProfileIn( 'wikidiff2_do_diff' );
 775                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 776                         $text .= $this->debug( 'wikidiff2' );
 777                         wfProfileOut( 'wikidiff2_do_diff' );
 778                         return $text;
 779                 }
 780                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 781                         # Diff via the shell
 782                         global $wgTmpDirectory;
 783                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 784                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 785
 786                         $tempFile1 = fopen( $tempName1, "w" );
 787                         if ( !$tempFile1 ) {
 788                                 wfProfileOut( __METHOD__ );
 789                                 return false;
 790                         }
 791                         $tempFile2 = fopen( $tempName2, "w" );
 792                         if ( !$tempFile2 ) {
 793                                 wfProfileOut( __METHOD__ );
 794                                 return false;
 795                         }
 796                         fwrite( $tempFile1, $otext );
 797                         fwrite( $tempFile2, $ntext );
 798                         fclose( $tempFile1 );
 799                         fclose( $tempFile2 );
 800                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 801                         wfProfileIn( __METHOD__ . "-shellexec" );
 802                         $difftext = wfShellExec( $cmd );
 803                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 804                         wfProfileOut( __METHOD__ . "-shellexec" );
 805                         unlink( $tempName1 );
 806                         unlink( $tempName2 );
 807                         return $difftext;
 808                 }
 809
 810                 # Native PHP diff
 811                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 812                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 813                 $diffs = new Diff( $ota, $nta );
 814                 $formatter = new TableDiffFormatter();
 815                 return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 816                 $this->debug();
 817         }
 818
 819         /**
 820          * Generate a debug comment indicating diff generating time,
 821          * server node, and generator backend.
 822          */
 823         protected function debug( $generator="internal" ) {
 824                 global $wgShowHostnames;
 825                 $data = array( $generator );
 826                 if( $wgShowHostnames ) {
 827                         $data[] = wfHostname();
 828                 }
 829                 $data[] = wfTimestamp( TS_DB );
 830                 return "<!-- diff generator: " .
 831                 implode( " ",
 832                 array_map(
 833                                         "htmlspecialchars",
 834                 $data ) ) .
 835                         " -->\n";
 836         }
 837
 838         /**
 839          * Replace line numbers with the text in the user's language
 840          */
 841         function localiseLineNumbers( $text ) {
 842                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 843                 array( &$this, 'localiseLineNumbersCb' ), $text );
 844         }
 845
 846         function localiseLineNumbersCb( $matches ) {
 847                 global $wgLang;
 848                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 849         }
 850
 851
 852         /**
 853          * If there are revisions between the ones being compared, return a note saying so.
 854          */
 855         function getMultiNotice() {
 856                 if ( !is_object($this->mOldRev) || !is_object($this->mNewRev) )
 857                 return '';
 858
 859                 if( !$this->mOldPage->equals( $this->mNewPage ) ) {
 860                         // Comparing two different pages? Count would be meaningless.
 861                         return '';
 862                 }
 863
 864                 $oldid = $this->mOldRev->getId();
 865                 $newid = $this->mNewRev->getId();
 866                 if ( $oldid > $newid ) {
 867                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 868                 }
 869
 870                 $n = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 871                 if ( !$n )
 872                 return '';
 873
 874                 return wfMsgExt( 'diff-multi', array( 'parseinline' ), $n );
 875         }
 876
 877
 878         /**
 879          * Add the header to a diff body
 880          */
 881         static function addHeader( $diff, $otitle, $ntitle, $multi = '' ) {
 882                 $colspan = 1;
 883                 $header = "<table class='diff'>";
 884                 if( $diff ) { // Safari/Chrome show broken output if cols not used
 885                         $header .= "
 886                         <col class='diff-marker' />
 887                         <col class='diff-content' />
 888                         <col class='diff-marker' />
 889                         <col class='diff-content' />";
 890                         $colspan = 2;
 891                 }
 892                 $header .= "
 893                 <tr valign='top'>
 894                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 895                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 896                 </tr>";
 897
 898                 if ( $multi != '' )
 899                 $header .= "<tr><td colspan='4' align='center' class='diff-multi'>{$multi}</td></tr>";
 900
 901                 return $header . $diff . "</table>";
 902         }
 903
 904         /**
 905          * Use specified text instead of loading from the database
 906          */
 907         function setText( $oldText, $newText ) {
 908                 $this->mOldtext = $oldText;
 909                 $this->mNewtext = $newText;
 910                 $this->mTextLoaded = 2;
 911                 $this->mRevisionsLoaded = true;
 912         }
 913
 914         /**
 915          * Load revision metadata for the specified articles. If newid is 0, then compare
 916          * the old article in oldid to the current article; if oldid is 0, then
 917          * compare the current article to the immediately previous one (ignoring the
 918          * value of newid).
 919          *
 920          * If oldid is false, leave the corresponding revision object set
 921          * to false. This is impossible via ordinary user input, and is provided for
 922          * API convenience.
 923          */
 924         function loadRevisionData() {
 925                 global $wgLang, $wgUser;
 926                 if ( $this->mRevisionsLoaded ) {
 927                         return true;
 928                 } else {
 929                         // Whether it succeeds or fails, we don't want to try again
 930                         $this->mRevisionsLoaded = true;
 931                 }
 932
 933                 // Load the new revision object
 934                 $this->mNewRev = $this->mNewid
 935                         ? Revision::newFromId( $this->mNewid )
 936                         : Revision::newFromTitle( $this->mTitle );
 937                 if( !$this->mNewRev instanceof Revision )
 938                         return false;
 939
 940                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 941                 $this->mNewid = $this->mNewRev->getId();
 942
 943                 // Check if page is editable
 944                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 945
 946                 // Set assorted variables
 947                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 948                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 949                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 950                 $this->mNewPage = $this->mNewRev->getTitle();
 951                 if( $this->mNewRev->isCurrent() ) {
 952                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 953                                 'oldid' => $this->mNewid
 954                         ) );
 955                         $this->mPagetitle = htmlspecialchars( wfMsg(
 956                                 'currentrev-asof',
 957                                 $timestamp,
 958                                 $dateofrev,
 959                                 $timeofrev
 960                         ) );
 961                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 962                                 'action' => 'edit'
 963                         ) );
 964
 965                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 966                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 967                 } else {
 968                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 969                                 'oldid' => $this->mNewid
 970                         ) );
 971                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 972                                 'action' => 'edit',
 973                                 'oldid' => $this->mNewid
 974                         ) );
 975                         $this->mPagetitle = htmlspecialchars( wfMsg(
 976                                 'revisionasof',
 977                                 $timestamp,
 978                                 $dateofrev,
 979                                 $timeofrev
 980                         ) );
 981
 982                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 983                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 984                 }
 985                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 986                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 987                 } else if ( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 988                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 989                 }
 990
 991                 // Load the old revision object
 992                 $this->mOldRev = false;
 993                 if( $this->mOldid ) {
 994                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 995                 } elseif ( $this->mOldid === 0 ) {
 996                         $rev = $this->mNewRev->getPrevious();
 997                         if( $rev ) {
 998                                 $this->mOldid = $rev->getId();
 999                                 $this->mOldRev = $rev;
1000                         } else {
1001                                 // No previous revision; mark to show as first-version only.
1002                                 $this->mOldid = false;
1003                                 $this->mOldRev = false;
1004                         }
1005                 }/* elseif ( $this->mOldid === false ) leave mOldRev false; */
1006
1007                 if( is_null( $this->mOldRev ) ) {
1008                         return false;
1009                 }
1010
1011                 if ( $this->mOldRev ) {
1012                         $this->mOldPage = $this->mOldRev->getTitle();
1013
1014                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1015                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1016                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1017                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1018                                 'oldid' => $this->mOldid
1019                         ) );
1020                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1021                                 'action' => 'edit',
1022                                 'oldid' => $this->mOldid
1023                         ) );
1024                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1025
1026                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1027                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1028                         // Add an "undo" link
1029                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
1030                                 'action' => 'edit',
1031                                 'undoafter' => $this->mOldid,
1032                                 'undo' => $this->mNewid
1033                         ) );
1034                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
1035                         $htmlTitle = $wgUser->getSkin()->tooltip( 'undo' );
1036                         if( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1037                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
1038                         }
1039
1040                         if( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1041                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1042                         } else if( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1043                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1044                         }
1045                 }
1046
1047                 return true;
1048         }
1049
1050         /**
1051          * Load the text of the revisions, as well as revision data.
1052          */
1053         function loadText() {
1054                 if ( $this->mTextLoaded == 2 ) {
1055                         return true;
1056                 } else {
1057                         // Whether it succeeds or fails, we don't want to try again
1058                         $this->mTextLoaded = 2;
1059                 }
1060
1061                 if ( !$this->loadRevisionData() ) {
1062                         return false;
1063                 }
1064                 if ( $this->mOldRev ) {
1065                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1066                         if ( $this->mOldtext === false ) {
1067                                 return false;
1068                         }
1069                 }
1070                 if ( $this->mNewRev ) {
1071                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1072                         if ( $this->mNewtext === false ) {
1073                                 return false;
1074                         }
1075                 }
1076                 return true;
1077         }
1078
1079         /**
1080          * Load the text of the new revision, not the old one
1081          */
1082         function loadNewText() {
1083                 if ( $this->mTextLoaded >= 1 ) {
1084                         return true;
1085                 } else {
1086                         $this->mTextLoaded = 1;
1087                 }
1088                 if ( !$this->loadRevisionData() ) {
1089                         return false;
1090                 }
1091                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1092                 return true;
1093         }
1094 }
1095
1096 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
1097 //
1098 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
1099 // You may copy this code freely under the conditions of the GPL.
1100 //
1101
1102 define('USE_ASSERTS', function_exists('assert'));
1103
1104 /**
1105  * @todo document
1106  * @private
1107  * @ingroup DifferenceEngine
1108  */
1109 class _DiffOp {
1110         var $type;
1111         var $orig;
1112         var $closing;
1113
1114         function reverse() {
1115                 trigger_error('pure virtual', E_USER_ERROR);
1116         }
1117
1118         function norig() {
1119                 return $this->orig ? sizeof($this->orig) : 0;
1120         }
1121
1122         function nclosing() {
1123                 return $this->closing ? sizeof($this->closing) : 0;
1124         }
1125 }
1126
1127 /**
1128  * @todo document
1129  * @private
1130  * @ingroup DifferenceEngine
1131  */
1132 class _DiffOp_Copy extends _DiffOp {
1133         var $type = 'copy';
1134
1135         function _DiffOp_Copy ($orig, $closing = false) {
1136                 if (!is_array($closing))
1137                 $closing = $orig;
1138                 $this->orig = $orig;
1139                 $this->closing = $closing;
1140         }
1141
1142         function reverse() {
1143                 return new _DiffOp_Copy($this->closing, $this->orig);
1144         }
1145 }
1146
1147 /**
1148  * @todo document
1149  * @private
1150  * @ingroup DifferenceEngine
1151  */
1152 class _DiffOp_Delete extends _DiffOp {
1153         var $type = 'delete';
1154
1155         function _DiffOp_Delete ($lines) {
1156                 $this->orig = $lines;
1157                 $this->closing = false;
1158         }
1159
1160         function reverse() {
1161                 return new _DiffOp_Add($this->orig);
1162         }
1163 }
1164
1165 /**
1166  * @todo document
1167  * @private
1168  * @ingroup DifferenceEngine
1169  */
1170 class _DiffOp_Add extends _DiffOp {
1171         var $type = 'add';
1172
1173         function _DiffOp_Add ($lines) {
1174                 $this->closing = $lines;
1175                 $this->orig = false;
1176         }
1177
1178         function reverse() {
1179                 return new _DiffOp_Delete($this->closing);
1180         }
1181 }
1182
1183 /**
1184  * @todo document
1185  * @private
1186  * @ingroup DifferenceEngine
1187  */
1188 class _DiffOp_Change extends _DiffOp {
1189         var $type = 'change';
1190
1191         function _DiffOp_Change ($orig, $closing) {
1192                 $this->orig = $orig;
1193                 $this->closing = $closing;
1194         }
1195
1196         function reverse() {
1197                 return new _DiffOp_Change($this->closing, $this->orig);
1198         }
1199 }
1200
1201 /**
1202  * Class used internally by Diff to actually compute the diffs.
1203  *
1204  * The algorithm used here is mostly lifted from the perl module
1205  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
1206  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
1207  *
1208  * More ideas are taken from:
1209  *       http://www.ics.uci.edu/~eppstein/161/960229.html
1210  *
1211  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
1212  * diffutils-2.7, which can be found at:
1213  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
1214  *
1215  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
1216  * are my own.
1217  *
1218  * Line length limits for robustness added by Tim Starling, 2005-08-31
1219  * Alternative implementation added by Guy Van den Broeck, 2008-07-30
1220  *
1221  * @author Geoffrey T. Dairiki, Tim Starling, Guy Van den Broeck
1222  * @private
1223  * @ingroup DifferenceEngine
1224  */
1225 class _DiffEngine {
1226
1227         const MAX_XREF_LENGTH =  10000;
1228
1229         function diff ($from_lines, $to_lines){
1230                 wfProfileIn( __METHOD__ );
1231
1232                 // Diff and store locally
1233                 $this->diff_local($from_lines, $to_lines);
1234
1235                 // Merge edits when possible
1236                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
1237                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
1238
1239                 // Compute the edit operations.
1240                 $n_from = sizeof($from_lines);
1241                 $n_to = sizeof($to_lines);
1242
1243                 $edits = array();
1244                 $xi = $yi = 0;
1245                 while ($xi < $n_from || $yi < $n_to) {
1246                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
1247                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
1248
1249                         // Skip matching "snake".
1250                         $copy = array();
1251                         while ( $xi < $n_from && $yi < $n_to
1252                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
1253                                 $copy[] = $from_lines[$xi++];
1254                                 ++$yi;
1255                         }
1256                         if ($copy)
1257                         $edits[] = new _DiffOp_Copy($copy);
1258
1259                         // Find deletes & adds.
1260                         $delete = array();
1261                         while ($xi < $n_from && $this->xchanged[$xi])
1262                         $delete[] = $from_lines[$xi++];
1263
1264                         $add = array();
1265                         while ($yi < $n_to && $this->ychanged[$yi])
1266                         $add[] = $to_lines[$yi++];
1267
1268                         if ($delete && $add)
1269                         $edits[] = new _DiffOp_Change($delete, $add);
1270                         elseif ($delete)
1271                         $edits[] = new _DiffOp_Delete($delete);
1272                         elseif ($add)
1273                         $edits[] = new _DiffOp_Add($add);
1274                 }
1275                 wfProfileOut( __METHOD__ );
1276                 return $edits;
1277         }
1278
1279         function diff_local ($from_lines, $to_lines) {
1280                 global $wgExternalDiffEngine;
1281                 wfProfileIn( __METHOD__);
1282
1283                 if($wgExternalDiffEngine == 'wikidiff3'){
1284                         // wikidiff3
1285                         $wikidiff3 = new WikiDiff3();
1286                         $wikidiff3->diff($from_lines, $to_lines);
1287                         $this->xchanged = $wikidiff3->removed;
1288                         $this->ychanged = $wikidiff3->added;
1289                         unset($wikidiff3);
1290                 }else{
1291                         // old diff
1292                         $n_from = sizeof($from_lines);
1293                         $n_to = sizeof($to_lines);
1294                         $this->xchanged = $this->ychanged = array();
1295                         $this->xv = $this->yv = array();
1296                         $this->xind = $this->yind = array();
1297                         unset($this->seq);
1298                         unset($this->in_seq);
1299                         unset($this->lcs);
1300
1301                         // Skip leading common lines.
1302                         for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
1303                                 if ($from_lines[$skip] !== $to_lines[$skip])
1304                                 break;
1305                                 $this->xchanged[$skip] = $this->ychanged[$skip] = false;
1306                         }
1307                         // Skip trailing common lines.
1308                         $xi = $n_from; $yi = $n_to;
1309                         for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
1310                                 if ($from_lines[$xi] !== $to_lines[$yi])
1311                                 break;
1312                                 $this->xchanged[$xi] = $this->ychanged[$yi] = false;
1313                         }
1314
1315                         // Ignore lines which do not exist in both files.
1316                         for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
1317                                 $xhash[$this->_line_hash($from_lines[$xi])] = 1;
1318                         }
1319
1320                         for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
1321                                 $line = $to_lines[$yi];
1322                                 if ( ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) )
1323                                 continue;
1324                                 $yhash[$this->_line_hash($line)] = 1;
1325                                 $this->yv[] = $line;
1326                                 $this->yind[] = $yi;
1327                         }
1328                         for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
1329                                 $line = $from_lines[$xi];
1330                                 if ( ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) )
1331                                 continue;
1332                                 $this->xv[] = $line;
1333                                 $this->xind[] = $xi;
1334                         }
1335
1336                         // Find the LCS.
1337                         $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
1338                 }
1339                 wfProfileOut( __METHOD__ );
1340         }
1341
1342         /**
1343          * Returns the whole line if it's small enough, or the MD5 hash otherwise
1344          */
1345         function _line_hash( $line ) {
1346                 if ( strlen( $line ) > self::MAX_XREF_LENGTH ) {
1347                         return md5( $line );
1348                 } else {
1349                         return $line;
1350                 }
1351         }
1352
1353         /* Divide the Largest Common Subsequence (LCS) of the sequences
1354          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
1355          * sized segments.
1356          *
1357          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
1358          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
1359          * sub sequences.  The first sub-sequence is contained in [X0, X1),
1360          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
1361          * that (X0, Y0) == (XOFF, YOFF) and
1362          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
1363          *
1364          * This function assumes that the first lines of the specified portions
1365          * of the two files do not match, and likewise that the last lines do not
1366          * match.  The caller must trim matching lines from the beginning and end
1367          * of the portions it is going to specify.
1368          */
1369         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
1370                 $flip = false;
1371
1372                 if ($xlim - $xoff > $ylim - $yoff) {
1373                         // Things seems faster (I'm not sure I understand why)
1374                         // when the shortest sequence in X.
1375                         $flip = true;
1376                         list ($xoff, $xlim, $yoff, $ylim)
1377                         = array( $yoff, $ylim, $xoff, $xlim);
1378                 }
1379
1380                 if ($flip)
1381                 for ($i = $ylim - 1; $i >= $yoff; $i--)
1382                 $ymatches[$this->xv[$i]][] = $i;
1383                 else
1384                 for ($i = $ylim - 1; $i >= $yoff; $i--)
1385                 $ymatches[$this->yv[$i]][] = $i;
1386
1387                 $this->lcs = 0;
1388                 $this->seq[0]= $yoff - 1;
1389                 $this->in_seq = array();
1390                 $ymids[0] = array();
1391
1392                 $numer = $xlim - $xoff + $nchunks - 1;
1393                 $x = $xoff;
1394                 for ($chunk = 0; $chunk < $nchunks; $chunk++) {
1395                         if ($chunk > 0)
1396                         for ($i = 0; $i <= $this->lcs; $i++)
1397                         $ymids[$i][$chunk-1] = $this->seq[$i];
1398
1399                         $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
1400                         for ( ; $x < $x1; $x++) {
1401                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
1402                                 if (empty($ymatches[$line]))
1403                                 continue;
1404                                 $matches = $ymatches[$line];
1405                                 reset($matches);
1406                                 while (list ($junk, $y) = each($matches))
1407                                 if (empty($this->in_seq[$y])) {
1408                                         $k = $this->_lcs_pos($y);
1409                                         USE_ASSERTS && assert($k > 0);
1410                                         $ymids[$k] = $ymids[$k-1];
1411                                         break;
1412                                 }
1413                                 while (list ( /* $junk */, $y) = each($matches)) {
1414                                         if ($y > $this->seq[$k-1]) {
1415                                                 USE_ASSERTS && assert($y < $this->seq[$k]);
1416                                                 // Optimization: this is a common case:
1417                                                 //      next match is just replacing previous match.
1418                                                 $this->in_seq[$this->seq[$k]] = false;
1419                                                 $this->seq[$k] = $y;
1420                                                 $this->in_seq[$y] = 1;
1421                                         } else if (empty($this->in_seq[$y])) {
1422                                                 $k = $this->_lcs_pos($y);
1423                                                 USE_ASSERTS && assert($k > 0);
1424                                                 $ymids[$k] = $ymids[$k-1];
1425                                         }
1426                                 }
1427                         }
1428                 }
1429
1430                 $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
1431                 $ymid = $ymids[$this->lcs];
1432                 for ($n = 0; $n < $nchunks - 1; $n++) {
1433                         $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
1434                         $y1 = $ymid[$n] + 1;
1435                         $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
1436                 }
1437                 $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
1438
1439                 return array($this->lcs, $seps);
1440         }
1441
1442         function _lcs_pos ($ypos) {
1443                 $end = $this->lcs;
1444                 if ($end == 0 || $ypos > $this->seq[$end]) {
1445                         $this->seq[++$this->lcs] = $ypos;
1446                         $this->in_seq[$ypos] = 1;
1447                         return $this->lcs;
1448                 }
1449
1450                 $beg = 1;
1451                 while ($beg < $end) {
1452                         $mid = (int)(($beg + $end) / 2);
1453                         if ( $ypos > $this->seq[$mid] )
1454                         $beg = $mid + 1;
1455                         else
1456                         $end = $mid;
1457                 }
1458
1459                 USE_ASSERTS && assert($ypos != $this->seq[$end]);
1460
1461                 $this->in_seq[$this->seq[$end]] = false;
1462                 $this->seq[$end] = $ypos;
1463                 $this->in_seq[$ypos] = 1;
1464                 return $end;
1465         }
1466
1467         /* Find LCS of two sequences.
1468          *
1469          * The results are recorded in the vectors $this->{x,y}changed[], by
1470          * storing a 1 in the element for each line that is an insertion
1471          * or deletion (ie. is not in the LCS).
1472          *
1473          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
1474          *
1475          * Note that XLIM, YLIM are exclusive bounds.
1476          * All line numbers are origin-0 and discarded lines are not counted.
1477          */
1478         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
1479                 // Slide down the bottom initial diagonal.
1480                 while ($xoff < $xlim && $yoff < $ylim
1481                 && $this->xv[$xoff] == $this->yv[$yoff]) {
1482                         ++$xoff;
1483                         ++$yoff;
1484                 }
1485
1486                 // Slide up the top initial diagonal.
1487                 while ($xlim > $xoff && $ylim > $yoff
1488                 && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
1489                         --$xlim;
1490                         --$ylim;
1491                 }
1492
1493                 if ($xoff == $xlim || $yoff == $ylim)
1494                 $lcs = 0;
1495                 else {
1496                         // This is ad hoc but seems to work well.
1497                         //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
1498                         //$nchunks = max(2,min(8,(int)$nchunks));
1499                         $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
1500                         list ($lcs, $seps)
1501                         = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
1502                 }
1503
1504                 if ($lcs == 0) {
1505                         // X and Y sequences have no common subsequence:
1506                         // mark all changed.
1507                         while ($yoff < $ylim)
1508                         $this->ychanged[$this->yind[$yoff++]] = 1;
1509                         while ($xoff < $xlim)
1510                         $this->xchanged[$this->xind[$xoff++]] = 1;
1511                 } else {
1512                         // Use the partitions to split this problem into subproblems.
1513                         reset($seps);
1514                         $pt1 = $seps[0];
1515                         while ($pt2 = next($seps)) {
1516                                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
1517                                 $pt1 = $pt2;
1518                         }
1519                 }
1520         }
1521
1522         /* Adjust inserts/deletes of identical lines to join changes
1523          * as much as possible.
1524          *
1525          * We do something when a run of changed lines include a
1526          * line at one end and has an excluded, identical line at the other.
1527          * We are free to choose which identical line is included.
1528          * `compareseq' usually chooses the one at the beginning,
1529          * but usually it is cleaner to consider the following identical line
1530          * to be the "change".
1531          *
1532          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
1533          */
1534         function _shift_boundaries ($lines, &$changed, $other_changed) {
1535                 wfProfileIn( __METHOD__ );
1536                 $i = 0;
1537                 $j = 0;
1538
1539                 USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
1540                 $len = sizeof($lines);
1541                 $other_len = sizeof($other_changed);
1542
1543                 while (1) {
1544                         /*
1545                          * Scan forwards to find beginning of another run of changes.
1546                          * Also keep track of the corresponding point in the other file.
1547                          *
1548                          * Throughout this code, $i and $j are adjusted together so that
1549                          * the first $i elements of $changed and the first $j elements
1550                          * of $other_changed both contain the same number of zeros
1551                          * (unchanged lines).
1552                          * Furthermore, $j is always kept so that $j == $other_len or
1553                          * $other_changed[$j] == false.
1554                          */
1555                         while ($j < $other_len && $other_changed[$j])
1556                         $j++;
1557
1558                         while ($i < $len && ! $changed[$i]) {
1559                                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
1560                                 $i++; $j++;
1561                                 while ($j < $other_len && $other_changed[$j])
1562                                 $j++;
1563                         }
1564
1565                         if ($i == $len)
1566                         break;
1567
1568                         $start = $i;
1569
1570                         // Find the end of this run of changes.
1571                         while (++$i < $len && $changed[$i])
1572                         continue;
1573
1574                         do {
1575                                 /*
1576                                  * Record the length of this run of changes, so that
1577                                  * we can later determine whether the run has grown.
1578                                  */
1579                                 $runlength = $i - $start;
1580
1581                                 /*
1582                                  * Move the changed region back, so long as the
1583                                  * previous unchanged line matches the last changed one.
1584                                  * This merges with previous changed regions.
1585                                  */
1586                                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
1587                                         $changed[--$start] = 1;
1588                                         $changed[--$i] = false;
1589                                         while ($start > 0 && $changed[$start - 1])
1590                                         $start--;
1591                                         USE_ASSERTS && assert('$j > 0');
1592                                         while ($other_changed[--$j])
1593                                         continue;
1594                                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
1595                                 }
1596
1597                                 /*
1598                                  * Set CORRESPONDING to the end of the changed run, at the last
1599                                  * point where it corresponds to a changed run in the other file.
1600                                  * CORRESPONDING == LEN means no such point has been found.
1601                                  */
1602                                 $corresponding = $j < $other_len ? $i : $len;
1603
1604                                 /*
1605                                  * Move the changed region forward, so long as the
1606                                  * first changed line matches the following unchanged one.
1607                                  * This merges with following changed regions.
1608                                  * Do this second, so that if there are no merges,
1609                                  * the changed region is moved forward as far as possible.
1610                                  */
1611                                 while ($i < $len && $lines[$start] == $lines[$i]) {
1612                                         $changed[$start++] = false;
1613                                         $changed[$i++] = 1;
1614                                         while ($i < $len && $changed[$i])
1615                                         $i++;
1616
1617                                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
1618                                         $j++;
1619                                         if ($j < $other_len && $other_changed[$j]) {
1620                                                 $corresponding = $i;
1621                                                 while ($j < $other_len && $other_changed[$j])
1622                                                 $j++;
1623                                         }
1624                                 }
1625                         } while ($runlength != $i - $start);
1626
1627                         /*
1628                          * If possible, move the fully-merged run of changes
1629                          * back to a corresponding run in the other file.
1630                          */
1631                         while ($corresponding < $i) {
1632                                 $changed[--$start] = 1;
1633                                 $changed[--$i] = 0;
1634                                 USE_ASSERTS && assert('$j > 0');
1635                                 while ($other_changed[--$j])
1636                                 continue;
1637                                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
1638                         }
1639                 }
1640                 wfProfileOut( __METHOD__ );
1641         }
1642 }
1643
1644 /**
1645  * Class representing a 'diff' between two sequences of strings.
1646  * @todo document
1647  * @private
1648  * @ingroup DifferenceEngine
1649  */
1650 class Diff
1651 {
1652         var $edits;
1653
1654         /**
1655          * Constructor.
1656          * Computes diff between sequences of strings.
1657          *
1658          * @param $from_lines array An array of strings.
1659          *                (Typically these are lines from a file.)
1660          * @param $to_lines array An array of strings.
1661          */
1662         function Diff($from_lines, $to_lines) {
1663                 $eng = new _DiffEngine;
1664                 $this->edits = $eng->diff($from_lines, $to_lines);
1665                 //$this->_check($from_lines, $to_lines);
1666         }
1667
1668         /**
1669          * Compute reversed Diff.
1670          *
1671          * SYNOPSIS:
1672          *
1673          *      $diff = new Diff($lines1, $lines2);
1674          *      $rev = $diff->reverse();
1675          * @return object A Diff object representing the inverse of the
1676          *                                original diff.
1677          */
1678         function reverse () {
1679                 $rev = $this;
1680                 $rev->edits = array();
1681                 foreach ($this->edits as $edit) {
1682                         $rev->edits[] = $edit->reverse();
1683                 }
1684                 return $rev;
1685         }
1686
1687         /**
1688          * Check for empty diff.
1689          *
1690          * @return bool True iff two sequences were identical.
1691          */
1692         function isEmpty () {
1693                 foreach ($this->edits as $edit) {
1694                         if ($edit->type != 'copy')
1695                         return false;
1696                 }
1697                 return true;
1698         }
1699
1700         /**
1701          * Compute the length of the Longest Common Subsequence (LCS).
1702          *
1703          * This is mostly for diagnostic purposed.
1704          *
1705          * @return int The length of the LCS.
1706          */
1707         function lcs () {
1708                 $lcs = 0;
1709                 foreach ($this->edits as $edit) {
1710                         if ($edit->type == 'copy')
1711                         $lcs += sizeof($edit->orig);
1712                 }
1713                 return $lcs;
1714         }
1715
1716         /**
1717          * Get the original set of lines.
1718          *
1719          * This reconstructs the $from_lines parameter passed to the
1720          * constructor.
1721          *
1722          * @return array The original sequence of strings.
1723          */
1724         function orig() {
1725                 $lines = array();
1726
1727                 foreach ($this->edits as $edit) {
1728                         if ($edit->orig)
1729                         array_splice($lines, sizeof($lines), 0, $edit->orig);
1730                 }
1731                 return $lines;
1732         }
1733
1734         /**
1735          * Get the closing set of lines.
1736          *
1737          * This reconstructs the $to_lines parameter passed to the
1738          * constructor.
1739          *
1740          * @return array The sequence of strings.
1741          */
1742         function closing() {
1743                 $lines = array();
1744
1745                 foreach ($this->edits as $edit) {
1746                         if ($edit->closing)
1747                         array_splice($lines, sizeof($lines), 0, $edit->closing);
1748                 }
1749                 return $lines;
1750         }
1751
1752         /**
1753          * Check a Diff for validity.
1754          *
1755          * This is here only for debugging purposes.
1756          */
1757         function _check ($from_lines, $to_lines) {
1758                 wfProfileIn( __METHOD__ );
1759                 if (serialize($from_lines) != serialize($this->orig()))
1760                 trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
1761                 if (serialize($to_lines) != serialize($this->closing()))
1762                 trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
1763
1764                 $rev = $this->reverse();
1765                 if (serialize($to_lines) != serialize($rev->orig()))
1766                 trigger_error("Reversed original doesn't match", E_USER_ERROR);
1767                 if (serialize($from_lines) != serialize($rev->closing()))
1768                 trigger_error("Reversed closing doesn't match", E_USER_ERROR);
1769
1770
1771                 $prevtype = 'none';
1772                 foreach ($this->edits as $edit) {
1773                         if ( $prevtype == $edit->type )
1774                         trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
1775                         $prevtype = $edit->type;
1776                 }
1777
1778                 $lcs = $this->lcs();
1779                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
1780                 wfProfileOut( __METHOD__ );
1781         }
1782 }
1783
1784 /**
1785  * @todo document, bad name.
1786  * @private
1787  * @ingroup DifferenceEngine
1788  */
1789 class MappedDiff extends Diff
1790 {
1791         /**
1792          * Constructor.
1793          *
1794          * Computes diff between sequences of strings.
1795          *
1796          * This can be used to compute things like
1797          * case-insensitve diffs, or diffs which ignore
1798          * changes in white-space.
1799          *
1800          * @param $from_lines array An array of strings.
1801          *      (Typically these are lines from a file.)
1802          *
1803          * @param $to_lines array An array of strings.
1804          *
1805          * @param $mapped_from_lines array This array should
1806          *      have the same size number of elements as $from_lines.
1807          *      The elements in $mapped_from_lines and
1808          *      $mapped_to_lines are what is actually compared
1809          *      when computing the diff.
1810          *
1811          * @param $mapped_to_lines array This array should
1812          *      have the same number of elements as $to_lines.
1813          */
1814         function MappedDiff($from_lines, $to_lines,
1815         $mapped_from_lines, $mapped_to_lines) {
1816                 wfProfileIn( __METHOD__ );
1817
1818                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
1819                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
1820
1821                 $this->Diff($mapped_from_lines, $mapped_to_lines);
1822
1823                 $xi = $yi = 0;
1824                 for ($i = 0; $i < sizeof($this->edits); $i++) {
1825                         $orig = &$this->edits[$i]->orig;
1826                         if (is_array($orig)) {
1827                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
1828                                 $xi += sizeof($orig);
1829                         }
1830
1831                         $closing = &$this->edits[$i]->closing;
1832                         if (is_array($closing)) {
1833                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
1834                                 $yi += sizeof($closing);
1835                         }
1836                 }
1837                 wfProfileOut( __METHOD__ );
1838         }
1839 }
1840
1841 /**
1842  * A class to format Diffs
1843  *
1844  * This class formats the diff in classic diff format.
1845  * It is intended that this class be customized via inheritance,
1846  * to obtain fancier outputs.
1847  * @todo document
1848  * @private
1849  * @ingroup DifferenceEngine
1850  */
1851 class DiffFormatter {
1852         /**
1853          * Number of leading context "lines" to preserve.
1854          *
1855          * This should be left at zero for this class, but subclasses
1856          * may want to set this to other values.
1857          */
1858         var $leading_context_lines = 0;
1859
1860         /**
1861          * Number of trailing context "lines" to preserve.
1862          *
1863          * This should be left at zero for this class, but subclasses
1864          * may want to set this to other values.
1865          */
1866         var $trailing_context_lines = 0;
1867
1868         /**
1869          * Format a diff.
1870          *
1871          * @param $diff object A Diff object.
1872          * @return string The formatted output.
1873          */
1874         function format($diff) {
1875                 wfProfileIn( __METHOD__ );
1876
1877                 $xi = $yi = 1;
1878                 $block = false;
1879                 $context = array();
1880
1881                 $nlead = $this->leading_context_lines;
1882                 $ntrail = $this->trailing_context_lines;
1883
1884                 $this->_start_diff();
1885
1886                 foreach ($diff->edits as $edit) {
1887                         if ($edit->type == 'copy') {
1888                                 if (is_array($block)) {
1889                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1890                                                 $block[] = $edit;
1891                                         }
1892                                         else{
1893                                                 if ($ntrail) {
1894                                                         $context = array_slice($edit->orig, 0, $ntrail);
1895                                                         $block[] = new _DiffOp_Copy($context);
1896                                                 }
1897                                                 $this->_block($x0, $ntrail + $xi - $x0,
1898                                                 $y0, $ntrail + $yi - $y0,
1899                                                 $block);
1900                                                 $block = false;
1901                                         }
1902                                 }
1903                                 $context = $edit->orig;
1904                         }
1905                         else {
1906                                 if (! is_array($block)) {
1907                                         $context = array_slice($context, sizeof($context) - $nlead);
1908                                         $x0 = $xi - sizeof($context);
1909                                         $y0 = $yi - sizeof($context);
1910                                         $block = array();
1911                                         if ($context)
1912                                         $block[] = new _DiffOp_Copy($context);
1913                                 }
1914                                 $block[] = $edit;
1915                         }
1916
1917                         if ($edit->orig)
1918                         $xi += sizeof($edit->orig);
1919                         if ($edit->closing)
1920                         $yi += sizeof($edit->closing);
1921                 }
1922
1923                 if (is_array($block))
1924                 $this->_block($x0, $xi - $x0,
1925                 $y0, $yi - $y0,
1926                 $block);
1927
1928                 $end = $this->_end_diff();
1929                 wfProfileOut( __METHOD__ );
1930                 return $end;
1931         }
1932
1933         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1934                 wfProfileIn( __METHOD__ );
1935                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1936                 foreach ($edits as $edit) {
1937                         if ($edit->type == 'copy')
1938                         $this->_context($edit->orig);
1939                         elseif ($edit->type == 'add')
1940                         $this->_added($edit->closing);
1941                         elseif ($edit->type == 'delete')
1942                         $this->_deleted($edit->orig);
1943                         elseif ($edit->type == 'change')
1944                         $this->_changed($edit->orig, $edit->closing);
1945                         else
1946                         trigger_error('Unknown edit type', E_USER_ERROR);
1947                 }
1948                 $this->_end_block();
1949                 wfProfileOut( __METHOD__ );
1950         }
1951
1952         function _start_diff() {
1953                 ob_start();
1954         }
1955
1956         function _end_diff() {
1957                 $val = ob_get_contents();
1958                 ob_end_clean();
1959                 return $val;
1960         }
1961
1962         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1963                 if ($xlen > 1)
1964                 $xbeg .= "," . ($xbeg + $xlen - 1);
1965                 if ($ylen > 1)
1966                 $ybeg .= "," . ($ybeg + $ylen - 1);
1967
1968                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1969         }
1970
1971         function _start_block($header) {
1972                 echo $header . "\n";
1973         }
1974
1975         function _end_block() {
1976         }
1977
1978         function _lines($lines, $prefix = ' ') {
1979                 foreach ($lines as $line)
1980                 echo "$prefix $line\n";
1981         }
1982
1983         function _context($lines) {
1984                 $this->_lines($lines);
1985         }
1986
1987         function _added($lines) {
1988                 $this->_lines($lines, '>');
1989         }
1990         function _deleted($lines) {
1991                 $this->_lines($lines, '<');
1992         }
1993
1994         function _changed($orig, $closing) {
1995                 $this->_deleted($orig);
1996                 echo "---\n";
1997                 $this->_added($closing);
1998         }
1999 }
2000
2001 /**
2002  * A formatter that outputs unified diffs
2003  * @ingroup DifferenceEngine
2004  */
2005
2006 class UnifiedDiffFormatter extends DiffFormatter {
2007         var $leading_context_lines = 2;
2008         var $trailing_context_lines = 2;
2009
2010         function _added($lines) {
2011                 $this->_lines($lines, '+');
2012         }
2013         function _deleted($lines) {
2014                 $this->_lines($lines, '-');
2015         }
2016         function _changed($orig, $closing) {
2017                 $this->_deleted($orig);
2018                 $this->_added($closing);
2019         }
2020         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
2021                 return "@@ -$xbeg,$xlen +$ybeg,$ylen @@";
2022         }
2023 }
2024
2025 /**
2026  * A pseudo-formatter that just passes along the Diff::$edits array
2027  * @ingroup DifferenceEngine
2028  */
2029 class ArrayDiffFormatter extends DiffFormatter {
2030         function format($diff) {
2031                 $oldline = 1;
2032                 $newline = 1;
2033                 $retval = array();
2034                 foreach($diff->edits as $edit)
2035                 switch($edit->type) {
2036                         case 'add':
2037                                 foreach($edit->closing as $l) {
2038                                         $retval[] = array(
2039                                                         'action' => 'add',
2040                                                         'new'=> $l,
2041                                                         'newline' => $newline++
2042                                         );
2043                                 }
2044                                 break;
2045                         case 'delete':
2046                                 foreach($edit->orig as $l) {
2047                                         $retval[] = array(
2048                                                         'action' => 'delete',
2049                                                         'old' => $l,
2050                                                         'oldline' => $oldline++,
2051                                         );
2052                                 }
2053                                 break;
2054                         case 'change':
2055                                 foreach($edit->orig as $i => $l) {
2056                                         $retval[] = array(
2057                                                         'action' => 'change',
2058                                                         'old' => $l,
2059                                                         'new' => @$edit->closing[$i],
2060                                                         'oldline' => $oldline++,
2061                                                         'newline' => $newline++,
2062                                         );
2063                                 }
2064                                 break;
2065                         case 'copy':
2066                                 $oldline += count($edit->orig);
2067                                 $newline += count($edit->orig);
2068                 }
2069                 return $retval;
2070         }
2071 }
2072
2073 /**
2074  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
2075  *
2076  */
2077
2078 define('NBSP', '&#160;'); // iso-8859-x non-breaking space.
2079
2080 /**
2081  * @todo document
2082  * @private
2083  * @ingroup DifferenceEngine
2084  */
2085 class _HWLDF_WordAccumulator {
2086         function _HWLDF_WordAccumulator () {
2087                 $this->_lines = array();
2088                 $this->_line = '';
2089                 $this->_group = '';
2090                 $this->_tag = '';
2091         }
2092
2093         function _flushGroup ($new_tag) {
2094                 if ($this->_group !== '') {
2095                         if ($this->_tag == 'ins')
2096                         $this->_line .= '<ins class="diffchange diffchange-inline">' .
2097                         htmlspecialchars ( $this->_group ) . '</ins>';
2098                         elseif ($this->_tag == 'del')
2099                         $this->_line .= '<del class="diffchange diffchange-inline">' .
2100                         htmlspecialchars ( $this->_group ) . '</del>';
2101                         else
2102                         $this->_line .= htmlspecialchars ( $this->_group );
2103                 }
2104                 $this->_group = '';
2105                 $this->_tag = $new_tag;
2106         }
2107
2108         function _flushLine ($new_tag) {
2109                 $this->_flushGroup($new_tag);
2110                 if ($this->_line != '')
2111                 array_push ( $this->_lines, $this->_line );
2112                 else
2113                 # make empty lines visible by inserting an NBSP
2114                 array_push ( $this->_lines, NBSP );
2115                 $this->_line = '';
2116         }
2117
2118         function addWords ($words, $tag = '') {
2119                 if ($tag != $this->_tag)
2120                 $this->_flushGroup($tag);
2121
2122                 foreach ($words as $word) {
2123                         // new-line should only come as first char of word.
2124                         if ($word == '')
2125                         continue;
2126                         if ($word[0] == "\n") {
2127                                 $this->_flushLine($tag);
2128                                 $word = substr($word, 1);
2129                         }
2130                         assert(!strstr($word, "\n"));
2131                         $this->_group .= $word;
2132                 }
2133         }
2134
2135         function getLines() {
2136                 $this->_flushLine('~done');
2137                 return $this->_lines;
2138         }
2139 }
2140
2141 /**
2142  * @todo document
2143  * @private
2144  * @ingroup DifferenceEngine
2145  */
2146 class WordLevelDiff extends MappedDiff {
2147         const MAX_LINE_LENGTH = 10000;
2148
2149         function WordLevelDiff ($orig_lines, $closing_lines) {
2150                 wfProfileIn( __METHOD__ );
2151
2152                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
2153                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
2154
2155                 $this->MappedDiff($orig_words, $closing_words,
2156                 $orig_stripped, $closing_stripped);
2157                 wfProfileOut( __METHOD__ );
2158         }
2159
2160         function _split($lines) {
2161                 wfProfileIn( __METHOD__ );
2162
2163                 $words = array();
2164                 $stripped = array();
2165                 $first = true;
2166                 foreach ( $lines as $line ) {
2167                         # If the line is too long, just pretend the entire line is one big word
2168                         # This prevents resource exhaustion problems
2169                         if ( $first ) {
2170                                 $first = false;
2171                         } else {
2172                                 $words[] = "\n";
2173                                 $stripped[] = "\n";
2174                         }
2175                         if ( strlen( $line ) > self::MAX_LINE_LENGTH ) {
2176                                 $words[] = $line;
2177                                 $stripped[] = $line;
2178                         } else {
2179                                 $m = array();
2180                                 if (preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
2181                                 $line, $m))
2182                                 {
2183                                         $words = array_merge( $words, $m[0] );
2184                                         $stripped = array_merge( $stripped, $m[1] );
2185                                 }
2186                         }
2187                 }
2188                 wfProfileOut( __METHOD__ );
2189                 return array($words, $stripped);
2190         }
2191
2192         function orig () {
2193                 wfProfileIn( __METHOD__ );
2194                 $orig = new _HWLDF_WordAccumulator;
2195
2196                 foreach ($this->edits as $edit) {
2197                         if ($edit->type == 'copy')
2198                         $orig->addWords($edit->orig);
2199                         elseif ($edit->orig)
2200                         $orig->addWords($edit->orig, 'del');
2201                 }
2202                 $lines = $orig->getLines();
2203                 wfProfileOut( __METHOD__ );
2204                 return $lines;
2205         }
2206
2207         function closing () {
2208                 wfProfileIn( __METHOD__ );
2209                 $closing = new _HWLDF_WordAccumulator;
2210
2211                 foreach ($this->edits as $edit) {
2212                         if ($edit->type == 'copy')
2213                         $closing->addWords($edit->closing);
2214                         elseif ($edit->closing)
2215                         $closing->addWords($edit->closing, 'ins');
2216                 }
2217                 $lines = $closing->getLines();
2218                 wfProfileOut( __METHOD__ );
2219                 return $lines;
2220         }
2221 }
2222
2223 /**
2224  * Wikipedia Table style diff formatter.
2225  * @todo document
2226  * @private
2227  * @ingroup DifferenceEngine
2228  */
2229 class TableDiffFormatter extends DiffFormatter {
2230         function TableDiffFormatter() {
2231                 $this->leading_context_lines = 2;
2232                 $this->trailing_context_lines = 2;
2233         }
2234
2235         public static function escapeWhiteSpace( $msg ) {
2236                 $msg = preg_replace( '/^ /m', '&nbsp; ', $msg );
2237                 $msg = preg_replace( '/ $/m', ' &nbsp;', $msg );
2238                 $msg = preg_replace( '/  /', '&nbsp; ', $msg );
2239                 return $msg;
2240         }
2241
2242         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
2243                 $r = '<tr><td colspan="2" class="diff-lineno"><!--LINE '.$xbeg."--></td>\n" .
2244                   '<td colspan="2" class="diff-lineno"><!--LINE '.$ybeg."--></td></tr>\n";
2245                 return $r;
2246         }
2247
2248         function _start_block( $header ) {
2249                 echo $header;
2250         }
2251
2252         function _end_block() {
2253         }
2254
2255         function _lines( $lines, $prefix=' ', $color='white' ) {
2256         }
2257
2258         # HTML-escape parameter before calling this
2259         function addedLine( $line ) {
2260                 return $this->wrapLine( '+', 'diff-addedline', $line );
2261         }
2262
2263         # HTML-escape parameter before calling this
2264         function deletedLine( $line ) {
2265                 return $this->wrapLine( '-', 'diff-deletedline', $line );
2266         }
2267
2268         # HTML-escape parameter before calling this
2269         function contextLine( $line ) {
2270                 return $this->wrapLine( ' ', 'diff-context', $line );
2271         }
2272
2273         private function wrapLine( $marker, $class, $line ) {
2274                 if( $line !== '' ) {
2275                         // The <div> wrapper is needed for 'overflow: auto' style to scroll properly
2276                         $line = Xml::tags( 'div', null, $this->escapeWhiteSpace( $line ) );
2277                 }
2278                 return "<td class='diff-marker'>$marker</td><td class='$class'>$line</td>";
2279         }
2280
2281         function emptyLine() {
2282                 return '<td colspan="2">&nbsp;</td>';
2283         }
2284
2285         function _added( $lines ) {
2286                 foreach ($lines as $line) {
2287                         echo '<tr>' . $this->emptyLine() .
2288                         $this->addedLine( '<ins class="diffchange">' .
2289                         htmlspecialchars ( $line ) . '</ins>' ) . "</tr>\n";
2290                 }
2291         }
2292
2293         function _deleted($lines) {
2294                 foreach ($lines as $line) {
2295                         echo '<tr>' . $this->deletedLine( '<del class="diffchange">' .
2296                         htmlspecialchars ( $line ) . '</del>' ) .
2297                         $this->emptyLine() . "</tr>\n";
2298                 }
2299         }
2300
2301         function _context( $lines ) {
2302                 foreach ($lines as $line) {
2303                         echo '<tr>' .
2304                         $this->contextLine( htmlspecialchars ( $line ) ) .
2305                         $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
2306                 }
2307         }
2308
2309         function _changed( $orig, $closing ) {
2310                 wfProfileIn( __METHOD__ );
2311
2312                 $diff = new WordLevelDiff( $orig, $closing );
2313                 $del = $diff->orig();
2314                 $add = $diff->closing();
2315
2316                 # Notice that WordLevelDiff returns HTML-escaped output.
2317                 # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
2318
2319                 while ( $line = array_shift( $del ) ) {
2320                         $aline = array_shift( $add );
2321                         echo '<tr>' . $this->deletedLine( $line ) .
2322                         $this->addedLine( $aline ) . "</tr>\n";
2323                 }
2324                 foreach ($add as $line) {       # If any leftovers
2325                         echo '<tr>' . $this->emptyLine() .
2326                         $this->addedLine( $line ) . "</tr>\n";
2327                 }
2328                 wfProfileOut( __METHOD__ );
2329         }
2330 }