includes/DifferenceEngine.php

   1 <?php
   2 /**
   3  * See diff.doc
   4  * @package MediaWiki
   5  * @subpackage DifferenceEngine
   6  */
   7
   8 /** */
   9 require_once( 'Revision.php' );
  10
  11 define( 'MAX_DIFF_LINE', 10000 );
  12 define( 'MAX_DIFF_XREF_LENGTH', 10000 );
  13
  14 /**
  15  * @todo document
  16  * @access public
  17  * @package MediaWiki
  18  * @subpackage DifferenceEngine
  19  */
  20 class DifferenceEngine {
  21         /**#@+
  22          * @access private
  23          */
  24         var $mOldid, $mNewid, $mTitle;
  25         var $mOldtitle, $mNewtitle, $mPagetitle;
  26         var $mOldtext, $mNewtext;
  27         var $mOldUser, $mNewUser;
  28         var $mOldComment, $mNewComment;
  29         var $mOldPage, $mNewPage;
  30         var $mRcidMarkPatrolled;
  31         var $mOldRev, $mNewRev;
  32         var $mRevisionsLoaded = false; // Have the revisions been loaded
  33         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  34         /**#@-*/
  35
  36         /**
  37          * Constructor
  38          * @param Title $titleObj Title object that the diff is associated with
  39          * @param integer $old Old ID we want to show and diff with.
  40          * @param string $new Either 'prev' or 'next'.
  41          * @param integer $rcid ??? (default 0)
  42          */
  43         function DifferenceEngine( $titleObj = null, $old = 0, $new = 0, $rcid = 0 ) {
  44                 $this->mTitle = $titleObj;
  45
  46                 if ( 'prev' == $new ) {
  47                         # Show diff between revision $old and the previous one.
  48                         # Get previous one from DB.
  49                         #
  50                         $this->mNewid = intval($old);
  51
  52                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  53
  54                 } elseif ( 'next' == $new ) {
  55                         # Show diff between revision $old and the previous one.
  56                         # Get previous one from DB.
  57                         #
  58                         $this->mOldid = intval($old);
  59                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  60                         if ( false === $this->mNewid ) {
  61                                 # if no result, NewId points to the newest old revision. The only newer
  62                                 # revision is cur, which is "0".
  63                                 $this->mNewid = 0;
  64                         }
  65
  66                 } else {
  67                         $this->mOldid = intval($old);
  68                         $this->mNewid = intval($new);
  69                 }
  70                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  71         }
  72
  73         function showDiffPage() {
  74                 global $wgUser, $wgOut, $wgContLang, $wgOnlySysopsCanPatrol,
  75                        $wgUseExternalEditor, $wgUseRCPatrol;
  76                 $fname = 'DifferenceEngine::showDiffPage';
  77                 wfProfileIn( $fname );
  78
  79                 # If external diffs are enabled both globally and for the user,
  80                 # we'll use the application/x-external-editor interface to call
  81                 # an external diff tool like kompare, kdiff3, etc.
  82                 if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
  83                         global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
  84                         $wgOut->disable();
  85                         header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
  86                         $url1=$this->mTitle->getFullURL("action=raw&oldid=".$this->mOldid);
  87                         $url2=$this->mTitle->getFullURL("action=raw&oldid=".$this->mNewid);
  88                         $special=$wgLang->getNsText(NS_SPECIAL);
  89                         $control=<<<CONTROL
  90 [Process]
  91 Type=Diff text
  92 Engine=MediaWiki
  93 Script={$wgServer}{$wgScript}
  94 Special namespace={$special}
  95
  96 [File]
  97 Extension=wiki
  98 URL=$url1
  99
 100 [File 2]
 101 Extension=wiki
 102 URL=$url2
 103 CONTROL;
 104                         echo($control);
 105                         return;
 106                 }
 107
 108                 # mOldid is false if the difference engine is called with a "vague" query for
 109                 # a diff between a version V and its previous version V' AND the version V
 110                 # is the first version of that article. In that case, V' does not exist.
 111                 if ( $this->mOldid === false ) {
 112                         $this->showFirstRevision();
 113                         wfProfileOut( $fname );
 114                         return;
 115                 }
 116
 117                 $t = $this->mTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 118                   "{$this->mNewid})";
 119                 $mtext = wfMsg( 'missingarticle', "<nowiki>$t</nowiki>" );
 120
 121                 $wgOut->setArticleFlag( false );
 122                 if ( ! $this->loadRevisionData() ) {
 123                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 124                         $wgOut->addWikitext( $mtext );
 125                         wfProfileOut( $fname );
 126                         return;
 127                 }
 128                 if ( $this->mNewRev->isCurrent() ) {
 129                         $wgOut->setArticleFlag( true );
 130                 }
 131
 132                 $wgOut->suppressQuickbar();
 133
 134                 $oldTitle = $this->mOldPage->getPrefixedText();
 135                 $newTitle = $this->mNewPage->getPrefixedText();
 136                 if( $oldTitle == $newTitle ) {
 137                         $wgOut->setPageTitle( $newTitle );
 138                 } else {
 139                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 140                 }
 141                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 142                 $wgOut->setRobotpolicy( 'noindex,follow' );
 143
 144                 if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
 145                         $wgOut->loginToUse();
 146                         $wgOut->output();
 147                         wfProfileOut( $fname );
 148                         exit;
 149                 }
 150
 151                 $sk = $wgUser->getSkin();
 152                 $talk = $wgContLang->getNsText( NS_TALK );
 153                 $contribs = wfMsg( 'contribslink' );
 154
 155                 $this->mOldComment = $sk->formatComment($this->mOldComment);
 156                 $this->mNewComment = $sk->formatComment($this->mNewComment);
 157
 158                 $oldUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 159                 $newUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mNewUser ), $this->mNewUser );
 160                 $oldUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ), $talk );
 161                 $newUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mNewUser ), $talk );
 162                 $oldContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 163                         'target=' . urlencode($this->mOldUser) );
 164                 $newContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 165                         'target=' . urlencode($this->mNewUser) );
 166                 if ( $this->mNewRev->isCurrent() && $wgUser->isAllowed('rollback') ) {
 167                         $rollback = '&nbsp;&nbsp;&nbsp;<strong>[' . $sk->makeKnownLinkObj( $this->mTitle, wfMsg( 'rollbacklink' ),
 168                                 'action=rollback&from=' . urlencode($this->mNewUser) .
 169                                 '&token=' . urlencode( $wgUser->editToken( array( $this->mTitle->getPrefixedText(), $this->mNewUser ) ) ) ) .
 170                                 ']</strong>';
 171                 } else {
 172                         $rollback = '';
 173                 }
 174                 if ( $wgUseRCPatrol && $this->mRcidMarkPatrolled != 0 && $wgUser->isLoggedIn() &&
 175                      ( $wgUser->isAllowed('rollback') || !$wgOnlySysopsCanPatrol ) )
 176                 {
 177                         $patrol = ' [' . $sk->makeKnownLinkObj( $this->mTitle, wfMsg( 'markaspatrolleddiff' ),
 178                                 "action=markpatrolled&rcid={$this->mRcidMarkPatrolled}" ) . ']';
 179                 } else {
 180                         $patrol = '';
 181                 }
 182
 183                 $prevlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'previousdiff' ),
 184                         'diff=prev&oldid='.$this->mOldid, '', '', 'id="differences-prevlink"' );
 185                 if ( $this->mNewRev->isCurrent() ) {
 186                         $nextlink = '';
 187                 } else {
 188                         $nextlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'nextdiff' ),
 189                                 'diff=next&oldid='.$this->mNewid, '', '', 'id="differences-nextlink"' );
 190                 }
 191
 192                 $oldHeader = "<strong>{$this->mOldtitle}</strong><br />$oldUserLink " .
 193                         "($oldUTLink | $oldContribs)<br />" . $this->mOldComment .
 194                         '<br />' . $prevlink;
 195                 $newHeader = "<strong>{$this->mNewtitle}</strong><br />$newUserLink " .
 196                         "($newUTLink | $newContribs) $rollback<br />" . $this->mNewComment .
 197                         '<br />' . $nextlink . $patrol;
 198
 199                 $this->showDiff( $oldHeader, $newHeader );
 200                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 201
 202                 if( !$this->mNewRev->isCurrent() ) {
 203                         $oldEditSectionSetting = $wgOut->mParserOptions->setEditSection( false );
 204                 }
 205
 206                 $this->loadNewText();
 207                 $wgOut->addWikiText( $this->mNewtext );
 208
 209                 if( !$this->mNewRev->isCurrent() ) {
 210                         $wgOut->mParserOptions->setEditSection( $oldEditSectionSetting );
 211                 }
 212
 213                 wfProfileOut( $fname );
 214         }
 215
 216         /**
 217          * Show the first revision of an article. Uses normal diff headers in
 218          * contrast to normal "old revision" display style.
 219          */
 220         function showFirstRevision() {
 221                 global $wgOut, $wgUser, $wgLang;
 222
 223                 $fname = 'DifferenceEngine::showFirstRevision';
 224                 wfProfileIn( $fname );
 225
 226                 # Get article text from the DB
 227                 #
 228                 if ( ! $this->loadNewText() ) {
 229                         $t = $this->mTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 230                           "{$this->mNewid})";
 231                         $mtext = wfMsg( 'missingarticle', "<nowiki>$t</nowiki>" );
 232                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 233                         $wgOut->addWikitext( $mtext );
 234                         wfProfileOut( $fname );
 235                         return;
 236                 }
 237                 if ( $this->mNewRev->isCurrent() ) {
 238                         $wgOut->setArticleFlag( true );
 239                 }
 240
 241                 # Check if user is allowed to look at this page. If not, bail out.
 242                 #
 243                 if ( !( $this->mTitle->userCanRead() ) ) {
 244                         $wgOut->loginToUse();
 245                         $wgOut->output();
 246                         wfProfileOut( $fname );
 247                         exit;
 248                 }
 249
 250                 # Prepare the header box
 251                 #
 252                 $sk = $wgUser->getSkin();
 253
 254                 $uTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ),  $wgLang->getNsText( NS_TALK ) );
 255                 $userLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 256                 $contribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), wfMsg( 'contribslink' ),
 257                         'target=' . urlencode($this->mOldUser) );
 258                 $nextlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid, '', '', 'id="differences-nextlink"' );
 259                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />$userLink " .
 260                         "($uTLink | $contribs)<br />" . $this->mOldComment .
 261                         '<br />' . $nextlink. "</div>\n";
 262
 263                 $wgOut->addHTML( $header );
 264
 265                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 266                 $wgOut->setRobotpolicy( 'noindex,follow' );
 267
 268
 269                 # Show current revision
 270                 #
 271                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 272                 $wgOut->addWikiText( $this->mNewtext );
 273
 274                 wfProfileOut( $fname );
 275         }
 276
 277         /**
 278          * Get the diff text, send it to $wgOut
 279          * Returns false if the diff could not be generated, otherwise returns true
 280          */
 281         function showDiff( $otitle, $ntitle ) {
 282                 global $wgOut;
 283                 $diff = $this->getDiff( $otitle, $ntitle );
 284                 if ( $diff === false ) {
 285                         $wgOut->addWikitext( wfMsg( 'missingarticle', "<nowiki>$t</nowiki>" ) );
 286                         return false;
 287                 } else {
 288                         $wgOut->addHTML( $diff );
 289                         return true;
 290                 }
 291         }
 292
 293         /**
 294          * Get diff table, including header
 295          * Note that the interface has changed, it's no longer static.
 296          * Returns false on error
 297          */
 298         function getDiff( $otitle, $ntitle ) {
 299                 $body = $this->getDiffBody();
 300                 if ( $body === false ) {
 301                         return false;
 302                 } else {
 303                         return $this->addHeader( $body, $otitle, $ntitle );
 304                 }
 305         }
 306
 307         /**
 308          * Get the diff table body, without header
 309          * Returns false on error
 310          */
 311         function getDiffBody() {
 312                 global $wgUseExternalDiffEngine, $wgContLang, $wgMemc, $wgDBname;
 313
 314                 // Cacheable?
 315                 $key = false;
 316                 if ( $this->mOldid && $this->mNewid ) {
 317                         // Try cache
 318                         $key = "$wgDBname:diff:oldid:{$this->mOldid}:newid:{$this->mNewid}";
 319                         $difftext = $wgMemc->get( $key );
 320                         if ( $difftext ) {
 321                                 return $difftext;
 322                         }
 323                 }
 324
 325                 if ( !$this->loadText() ) {
 326                         return false;
 327                 }
 328
 329                 $otext = $wgContLang->segmentForDiff($this->mOldtext);
 330                 $ntext = $wgContLang->segmentForDiff($this->mNewtext);
 331                 if ( $wgUseExternalDiffEngine ) {
 332                         # For historical reasons, external diff engine expects
 333                         # input text to be HTML-escaped already
 334                         $otext = str_replace( "\r\n", "\n", htmlspecialchars ( $otext ) );
 335                         $ntext = str_replace( "\r\n", "\n", htmlspecialchars ( $ntext ) );
 336                         if( !function_exists( 'wikidiff_do_diff' ) ) {
 337                                 dl('php_wikidiff.so');
 338                         }
 339                         $difftext = wikidiff_do_diff( $otext, $ntext, 2 );
 340                 } else {
 341                         $ota = explode( "\n", str_replace( "\r\n", "\n", $otext ) );
 342                         $nta = explode( "\n", str_replace( "\r\n", "\n", $ntext ) );
 343                         $diffs =& new Diff( $ota, $nta );
 344                         $formatter =& new TableDiffFormatter();
 345                         $difftext = $formatter->format( $diffs );
 346                 }
 347                 $difftext = $wgContLang->unsegmentForDiff($difftext);
 348
 349                 // Save to cache for 7 days
 350                 if ( $key !== false ) {
 351                         $wgMemc->set( $key, $difftext, 7*86400 );
 352                 }
 353                 return $difftext;
 354         }
 355
 356         /**
 357          * Add the header to a diff body
 358          */
 359         function addHeader( $diff, $otitle, $ntitle ) {
 360                 $out = "
 361                         <table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
 362                         <tr>
 363                                 <td colspan='2' width='50%' align='center' class='diff-otitle'>{$otitle}</td>
 364                                 <td colspan='2' width='50%' align='center' class='diff-ntitle'>{$ntitle}</td>
 365                         </tr>
 366                         $diff
 367                         </table>
 368                 ";
 369                 return $out;
 370         }
 371
 372         /**
 373          * Use specified text instead of loading from the database
 374          */
 375         function setText( $oldText, $newText ) {
 376                 $this->mOldtext = $oldText;
 377                 $this->mNewtext = $newText;
 378                 $this->mTextLoaded = 2;
 379         }
 380
 381         /**
 382          * Load revision metadata for the specified articles. If newid is 0, then compare
 383          * the old article in oldid to the current article; if oldid is 0, then
 384          * compare the current article to the immediately previous one (ignoring the
 385          * value of newid).
 386          *
 387          * If oldid is false, leave the corresponding revision object set
 388          * to false. This is impossible via ordinary user input, and is provided for
 389          * API convenience.
 390          */
 391         function loadRevisionData() {
 392                 global $wgLang;
 393                 if ( $this->mRevisionsLoaded ) {
 394                         return true;
 395                 } else {
 396                         // Whether it succeeds or fails, we don't want to try again
 397                         $this->mRevisionsLoaded = true;
 398                 }
 399
 400                 // Load the new revision object
 401                 if( $this->mNewid ) {
 402                         $this->mNewRev = Revision::newFromId( $this->mNewid );
 403                 } else {
 404                         $this->mNewRev = Revision::newFromTitle( $this->mTitle );
 405                 }
 406
 407                 if( is_null( $this->mNewRev ) ) {
 408                         return false;
 409                 }
 410
 411                 // Set assorted variables
 412                 if( $this->mNewRev->isCurrent() ) {
 413                         $this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
 414                         $this->mNewPage = $this->mTitle;
 415                         $newLink = $this->mNewPage->escapeLocalUrl();
 416                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 417                 } else {
 418                         $this->mNewPage = $this->mNewRev->getTitle();
 419                         $newLink = $this->mNewPage->escapeLocalUrl ('oldid=' . $this->mNewid );
 420                         $t = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 421                         $this->mPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
 422                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 423                 }
 424
 425                 $this->mNewUser = $this->mNewRev->getUserText();
 426                 $this->mNewComment = $this->mNewRev->getComment();
 427
 428                 // Load the old revision object
 429                 $this->mOldRev = false;
 430                 if( $this->mOldid ) {
 431                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 432                 } elseif ( $this->mOldid === 0 ) {
 433                         $this->mOldRev = $this->mNewRev->getPrevious();
 434                         $this->mOldid = $this->mOldRev->getId();
 435                 }/* elseif ( $this->mOldid === false ) leave mOldRev false; */
 436
 437                 if( is_null( $this->mOldRev ) ) {
 438                         return false;
 439                 }
 440
 441                 if ( $this->mOldRev ) {
 442                         $this->mOldPage = $this->mOldRev->getTitle();
 443
 444                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
 445                         $oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
 446                         $this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) ) . '</a>';
 447
 448
 449                         $this->mOldUser = $this->mOldRev->getUserText();
 450                         $this->mOldComment = $this->mOldRev->getComment();
 451                 }
 452
 453                 return true;
 454         }
 455
 456         /**
 457          * Load the text of the revisions, as well as revision data.
 458          */
 459         function loadText() {
 460                 if ( $this->mTextLoaded == 2 ) {
 461                         return true;
 462                 } else {
 463                         // Whether it succeeds or fails, we don't want to try again
 464                         $this->mTextLoaded = 2;
 465                 }
 466
 467                 if ( !$this->loadRevisionData() ) {
 468                         return false;
 469                 }
 470                 if ( $this->mOldRev ) {
 471                         $this->mOldtext = $this->mOldRev->getText();
 472                 }
 473                 if ( $this->mNewRev ) {
 474                         $this->mNewtext = $this->mNewRev->getText();
 475                 }
 476                 return true;
 477         }
 478
 479         /**
 480          * Load the text of the new revision, not the old one
 481          */
 482         function loadNewText() {
 483                 if ( $this->mTextLoaded >= 1 ) {
 484                         return true;
 485                 } else {
 486                         $this->mTextLoaded = 1;
 487                 }
 488                 if ( !$this->loadRevisionData() ) {
 489                         return false;
 490                 }
 491                 $this->mNewtext = $this->mNewRev->getText();
 492                 return true;
 493         }
 494
 495
 496 }
 497
 498 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
 499 //
 500 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 501 // You may copy this code freely under the conditions of the GPL.
 502 //
 503
 504 define('USE_ASSERTS', function_exists('assert'));
 505
 506 /**
 507  * @todo document
 508  * @access private
 509  * @package MediaWiki
 510  * @subpackage DifferenceEngine
 511  */
 512 class _DiffOp {
 513         var $type;
 514         var $orig;
 515         var $closing;
 516
 517         function reverse() {
 518                 trigger_error('pure virtual', E_USER_ERROR);
 519         }
 520
 521         function norig() {
 522                 return $this->orig ? sizeof($this->orig) : 0;
 523         }
 524
 525         function nclosing() {
 526                 return $this->closing ? sizeof($this->closing) : 0;
 527         }
 528 }
 529
 530 /**
 531  * @todo document
 532  * @access private
 533  * @package MediaWiki
 534  * @subpackage DifferenceEngine
 535  */
 536 class _DiffOp_Copy extends _DiffOp {
 537         var $type = 'copy';
 538
 539         function _DiffOp_Copy ($orig, $closing = false) {
 540                 if (!is_array($closing))
 541                         $closing = $orig;
 542                 $this->orig = $orig;
 543                 $this->closing = $closing;
 544         }
 545
 546         function reverse() {
 547                 return new _DiffOp_Copy($this->closing, $this->orig);
 548         }
 549 }
 550
 551 /**
 552  * @todo document
 553  * @access private
 554  * @package MediaWiki
 555  * @subpackage DifferenceEngine
 556  */
 557 class _DiffOp_Delete extends _DiffOp {
 558         var $type = 'delete';
 559
 560         function _DiffOp_Delete ($lines) {
 561                 $this->orig = $lines;
 562                 $this->closing = false;
 563         }
 564
 565         function reverse() {
 566                 return new _DiffOp_Add($this->orig);
 567         }
 568 }
 569
 570 /**
 571  * @todo document
 572  * @access private
 573  * @package MediaWiki
 574  * @subpackage DifferenceEngine
 575  */
 576 class _DiffOp_Add extends _DiffOp {
 577         var $type = 'add';
 578
 579         function _DiffOp_Add ($lines) {
 580                 $this->closing = $lines;
 581                 $this->orig = false;
 582         }
 583
 584         function reverse() {
 585                 return new _DiffOp_Delete($this->closing);
 586         }
 587 }
 588
 589 /**
 590  * @todo document
 591  * @access private
 592  * @package MediaWiki
 593  * @subpackage DifferenceEngine
 594  */
 595 class _DiffOp_Change extends _DiffOp {
 596         var $type = 'change';
 597
 598         function _DiffOp_Change ($orig, $closing) {
 599                 $this->orig = $orig;
 600                 $this->closing = $closing;
 601         }
 602
 603         function reverse() {
 604                 return new _DiffOp_Change($this->closing, $this->orig);
 605         }
 606 }
 607
 608
 609 /**
 610  * Class used internally by Diff to actually compute the diffs.
 611  *
 612  * The algorithm used here is mostly lifted from the perl module
 613  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
 614  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
 615  *
 616  * More ideas are taken from:
 617  *       http://www.ics.uci.edu/~eppstein/161/960229.html
 618  *
 619  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
 620  * diffutils-2.7, which can be found at:
 621  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
 622  *
 623  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
 624  * are my own.
 625  *
 626  * Line length limits for robustness added by Tim Starling, 2005-08-31
 627  *
 628  * @author Geoffrey T. Dairiki, Tim Starling
 629  * @access private
 630  * @package MediaWiki
 631  * @subpackage DifferenceEngine
 632  */
 633 class _DiffEngine
 634 {
 635         function diff ($from_lines, $to_lines) {
 636                 $fname = '_DiffEngine::diff';
 637                 wfProfileIn( $fname );
 638
 639                 $n_from = sizeof($from_lines);
 640                 $n_to = sizeof($to_lines);
 641
 642                 $this->xchanged = $this->ychanged = array();
 643                 $this->xv = $this->yv = array();
 644                 $this->xind = $this->yind = array();
 645                 unset($this->seq);
 646                 unset($this->in_seq);
 647                 unset($this->lcs);
 648
 649                 // Skip leading common lines.
 650                 for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
 651                         if ($from_lines[$skip] != $to_lines[$skip])
 652                                 break;
 653                         $this->xchanged[$skip] = $this->ychanged[$skip] = false;
 654                 }
 655                 // Skip trailing common lines.
 656                 $xi = $n_from; $yi = $n_to;
 657                 for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
 658                         if ($from_lines[$xi] != $to_lines[$yi])
 659                                 break;
 660                         $this->xchanged[$xi] = $this->ychanged[$yi] = false;
 661                 }
 662
 663                 // Ignore lines which do not exist in both files.
 664                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 665                         $xhash[$this->_line_hash($from_lines[$xi])] = 1;
 666                 }
 667
 668                 for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
 669                         $line = $to_lines[$yi];
 670                         if ( ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) )
 671                                 continue;
 672                         $yhash[$this->_line_hash($line)] = 1;
 673                         $this->yv[] = $line;
 674                         $this->yind[] = $yi;
 675                 }
 676                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 677                         $line = $from_lines[$xi];
 678                         if ( ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) )
 679                                 continue;
 680                         $this->xv[] = $line;
 681                         $this->xind[] = $xi;
 682                 }
 683
 684                 // Find the LCS.
 685                 $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
 686
 687                 // Merge edits when possible
 688                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
 689                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
 690
 691                 // Compute the edit operations.
 692                 $edits = array();
 693                 $xi = $yi = 0;
 694                 while ($xi < $n_from || $yi < $n_to) {
 695                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
 696                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
 697
 698                         // Skip matching "snake".
 699                         $copy = array();
 700                         while ( $xi < $n_from && $yi < $n_to
 701                                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
 702                                 $copy[] = $from_lines[$xi++];
 703                                 ++$yi;
 704                         }
 705                         if ($copy)
 706                                 $edits[] = new _DiffOp_Copy($copy);
 707
 708                         // Find deletes & adds.
 709                         $delete = array();
 710                         while ($xi < $n_from && $this->xchanged[$xi])
 711                                 $delete[] = $from_lines[$xi++];
 712
 713                         $add = array();
 714                         while ($yi < $n_to && $this->ychanged[$yi])
 715                                 $add[] = $to_lines[$yi++];
 716
 717                         if ($delete && $add)
 718                                 $edits[] = new _DiffOp_Change($delete, $add);
 719                         elseif ($delete)
 720                                 $edits[] = new _DiffOp_Delete($delete);
 721                         elseif ($add)
 722                                 $edits[] = new _DiffOp_Add($add);
 723                 }
 724                 wfProfileOut( $fname );
 725                 return $edits;
 726         }
 727
 728         /**
 729          * Returns the whole line if it's small enough, or the MD5 hash otherwise
 730          */
 731         function _line_hash( $line ) {
 732                 if ( strlen( $line ) > MAX_DIFF_XREF_LENGTH ) {
 733                         return md5( $line );
 734                 } else {
 735                         return $line;
 736                 }
 737         }
 738
 739
 740         /* Divide the Largest Common Subsequence (LCS) of the sequences
 741          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
 742          * sized segments.
 743          *
 744          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
 745          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
 746          * sub sequences.  The first sub-sequence is contained in [X0, X1),
 747          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
 748          * that (X0, Y0) == (XOFF, YOFF) and
 749          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
 750          *
 751          * This function assumes that the first lines of the specified portions
 752          * of the two files do not match, and likewise that the last lines do not
 753          * match.  The caller must trim matching lines from the beginning and end
 754          * of the portions it is going to specify.
 755          */
 756         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
 757                 $fname = '_DiffEngine::_diag';
 758                 wfProfileIn( $fname );
 759                 $flip = false;
 760
 761                 if ($xlim - $xoff > $ylim - $yoff) {
 762                         // Things seems faster (I'm not sure I understand why)
 763                                 // when the shortest sequence in X.
 764                                 $flip = true;
 765                         list ($xoff, $xlim, $yoff, $ylim)
 766                         = array( $yoff, $ylim, $xoff, $xlim);
 767                 }
 768
 769                 if ($flip)
 770                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 771                                 $ymatches[$this->xv[$i]][] = $i;
 772                 else
 773                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 774                                 $ymatches[$this->yv[$i]][] = $i;
 775
 776                 $this->lcs = 0;
 777                 $this->seq[0]= $yoff - 1;
 778                 $this->in_seq = array();
 779                 $ymids[0] = array();
 780
 781                 $numer = $xlim - $xoff + $nchunks - 1;
 782                 $x = $xoff;
 783                 for ($chunk = 0; $chunk < $nchunks; $chunk++) {
 784                         wfProfileIn( "$fname-chunk" );
 785                         if ($chunk > 0)
 786                                 for ($i = 0; $i <= $this->lcs; $i++)
 787                                         $ymids[$i][$chunk-1] = $this->seq[$i];
 788
 789                         $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
 790                         for ( ; $x < $x1; $x++) {
 791                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
 792                                         if (empty($ymatches[$line]))
 793                                                 continue;
 794                                 $matches = $ymatches[$line];
 795                                 reset($matches);
 796                                 while (list ($junk, $y) = each($matches))
 797                                         if (empty($this->in_seq[$y])) {
 798                                                 $k = $this->_lcs_pos($y);
 799                                                 USE_ASSERTS && assert($k > 0);
 800                                                 $ymids[$k] = $ymids[$k-1];
 801                                                 break;
 802                                         }
 803                                 while (list ($junk, $y) = each($matches)) {
 804                                         if ($y > $this->seq[$k-1]) {
 805                                                 USE_ASSERTS && assert($y < $this->seq[$k]);
 806                                                 // Optimization: this is a common case:
 807                                                 //      next match is just replacing previous match.
 808                                                 $this->in_seq[$this->seq[$k]] = false;
 809                                                 $this->seq[$k] = $y;
 810                                                 $this->in_seq[$y] = 1;
 811                                         } else if (empty($this->in_seq[$y])) {
 812                                                 $k = $this->_lcs_pos($y);
 813                                                 USE_ASSERTS && assert($k > 0);
 814                                                 $ymids[$k] = $ymids[$k-1];
 815                                         }
 816                                 }
 817                         }
 818                         wfProfileOut( "$fname-chunk" );
 819                 }
 820
 821                 $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
 822                 $ymid = $ymids[$this->lcs];
 823                 for ($n = 0; $n < $nchunks - 1; $n++) {
 824                         $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
 825                         $y1 = $ymid[$n] + 1;
 826                         $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
 827                 }
 828                 $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
 829
 830                 wfProfileOut( $fname );
 831                 return array($this->lcs, $seps);
 832         }
 833
 834         function _lcs_pos ($ypos) {
 835                 $fname = '_DiffEngine::_lcs_pos';
 836                 wfProfileIn( $fname );
 837
 838                 $end = $this->lcs;
 839                 if ($end == 0 || $ypos > $this->seq[$end]) {
 840                         $this->seq[++$this->lcs] = $ypos;
 841                         $this->in_seq[$ypos] = 1;
 842                         wfProfileOut( $fname );
 843                         return $this->lcs;
 844                 }
 845
 846                 $beg = 1;
 847                 while ($beg < $end) {
 848                         $mid = (int)(($beg + $end) / 2);
 849                         if ( $ypos > $this->seq[$mid] )
 850                                 $beg = $mid + 1;
 851                         else
 852                                 $end = $mid;
 853                 }
 854
 855                 USE_ASSERTS && assert($ypos != $this->seq[$end]);
 856
 857                 $this->in_seq[$this->seq[$end]] = false;
 858                 $this->seq[$end] = $ypos;
 859                 $this->in_seq[$ypos] = 1;
 860                 wfProfileOut( $fname );
 861                 return $end;
 862         }
 863
 864         /* Find LCS of two sequences.
 865          *
 866          * The results are recorded in the vectors $this->{x,y}changed[], by
 867          * storing a 1 in the element for each line that is an insertion
 868          * or deletion (ie. is not in the LCS).
 869          *
 870          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
 871          *
 872          * Note that XLIM, YLIM are exclusive bounds.
 873          * All line numbers are origin-0 and discarded lines are not counted.
 874          */
 875         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
 876                 $fname = '_DiffEngine::_compareseq';
 877                 wfProfileIn( $fname );
 878
 879                 // Slide down the bottom initial diagonal.
 880                 while ($xoff < $xlim && $yoff < $ylim
 881                            && $this->xv[$xoff] == $this->yv[$yoff]) {
 882                         ++$xoff;
 883                         ++$yoff;
 884                 }
 885
 886                 // Slide up the top initial diagonal.
 887                 while ($xlim > $xoff && $ylim > $yoff
 888                            && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
 889                         --$xlim;
 890                         --$ylim;
 891                 }
 892
 893                 if ($xoff == $xlim || $yoff == $ylim)
 894                         $lcs = 0;
 895                 else {
 896                         // This is ad hoc but seems to work well.
 897                         //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
 898                         //$nchunks = max(2,min(8,(int)$nchunks));
 899                         $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
 900                         list ($lcs, $seps)
 901                         = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
 902                 }
 903
 904                 if ($lcs == 0) {
 905                         // X and Y sequences have no common subsequence:
 906                         // mark all changed.
 907                         while ($yoff < $ylim)
 908                                 $this->ychanged[$this->yind[$yoff++]] = 1;
 909                         while ($xoff < $xlim)
 910                                 $this->xchanged[$this->xind[$xoff++]] = 1;
 911                 } else {
 912                         // Use the partitions to split this problem into subproblems.
 913                         reset($seps);
 914                         $pt1 = $seps[0];
 915                         while ($pt2 = next($seps)) {
 916                                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
 917                                 $pt1 = $pt2;
 918                         }
 919                 }
 920                 wfProfileOut( $fname );
 921         }
 922
 923         /* Adjust inserts/deletes of identical lines to join changes
 924          * as much as possible.
 925          *
 926          * We do something when a run of changed lines include a
 927          * line at one end and has an excluded, identical line at the other.
 928          * We are free to choose which identical line is included.
 929          * `compareseq' usually chooses the one at the beginning,
 930          * but usually it is cleaner to consider the following identical line
 931          * to be the "change".
 932          *
 933          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
 934          */
 935         function _shift_boundaries ($lines, &$changed, $other_changed) {
 936                 $fname = '_DiffEngine::_shift_boundaries';
 937                 wfProfileIn( $fname );
 938                 $i = 0;
 939                 $j = 0;
 940
 941                 USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
 942                 $len = sizeof($lines);
 943                 $other_len = sizeof($other_changed);
 944
 945                 while (1) {
 946                         /*
 947                          * Scan forwards to find beginning of another run of changes.
 948                          * Also keep track of the corresponding point in the other file.
 949                          *
 950                          * Throughout this code, $i and $j are adjusted together so that
 951                          * the first $i elements of $changed and the first $j elements
 952                          * of $other_changed both contain the same number of zeros
 953                          * (unchanged lines).
 954                          * Furthermore, $j is always kept so that $j == $other_len or
 955                          * $other_changed[$j] == false.
 956                          */
 957                         while ($j < $other_len && $other_changed[$j])
 958                                 $j++;
 959
 960                         while ($i < $len && ! $changed[$i]) {
 961                                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 962                                 $i++; $j++;
 963                                 while ($j < $other_len && $other_changed[$j])
 964                                         $j++;
 965                         }
 966
 967                         if ($i == $len)
 968                                 break;
 969
 970                         $start = $i;
 971
 972                         // Find the end of this run of changes.
 973                         while (++$i < $len && $changed[$i])
 974                                 continue;
 975
 976                         do {
 977                                 /*
 978                                  * Record the length of this run of changes, so that
 979                                  * we can later determine whether the run has grown.
 980                                  */
 981                                 $runlength = $i - $start;
 982
 983                                 /*
 984                                  * Move the changed region back, so long as the
 985                                  * previous unchanged line matches the last changed one.
 986                                  * This merges with previous changed regions.
 987                                  */
 988                                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
 989                                         $changed[--$start] = 1;
 990                                         $changed[--$i] = false;
 991                                         while ($start > 0 && $changed[$start - 1])
 992                                                 $start--;
 993                                         USE_ASSERTS && assert('$j > 0');
 994                                         while ($other_changed[--$j])
 995                                                 continue;
 996                                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 997                                 }
 998
 999                                 /*
1000                                  * Set CORRESPONDING to the end of the changed run, at the last
1001                                  * point where it corresponds to a changed run in the other file.
1002                                  * CORRESPONDING == LEN means no such point has been found.
1003                                  */
1004                                 $corresponding = $j < $other_len ? $i : $len;
1005
1006                                 /*
1007                                  * Move the changed region forward, so long as the
1008                                  * first changed line matches the following unchanged one.
1009                                  * This merges with following changed regions.
1010                                  * Do this second, so that if there are no merges,
1011                                  * the changed region is moved forward as far as possible.
1012                                  */
1013                                 while ($i < $len && $lines[$start] == $lines[$i]) {
1014                                         $changed[$start++] = false;
1015                                         $changed[$i++] = 1;
1016                                         while ($i < $len && $changed[$i])
1017                                                 $i++;
1018
1019                                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
1020                                         $j++;
1021                                         if ($j < $other_len && $other_changed[$j]) {
1022                                                 $corresponding = $i;
1023                                                 while ($j < $other_len && $other_changed[$j])
1024                                                         $j++;
1025                                         }
1026                                 }
1027                         } while ($runlength != $i - $start);
1028
1029                         /*
1030                          * If possible, move the fully-merged run of changes
1031                          * back to a corresponding run in the other file.
1032                          */
1033                         while ($corresponding < $i) {
1034                                 $changed[--$start] = 1;
1035                                 $changed[--$i] = 0;
1036                                 USE_ASSERTS && assert('$j > 0');
1037                                 while ($other_changed[--$j])
1038                                         continue;
1039                                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
1040                         }
1041                 }
1042                 wfProfileOut( $fname );
1043         }
1044 }
1045
1046 /**
1047  * Class representing a 'diff' between two sequences of strings.
1048  * @todo document
1049  * @access private
1050  * @package MediaWiki
1051  * @subpackage DifferenceEngine
1052  */
1053 class Diff
1054 {
1055         var $edits;
1056
1057         /**
1058          * Constructor.
1059          * Computes diff between sequences of strings.
1060          *
1061          * @param $from_lines array An array of strings.
1062          *                (Typically these are lines from a file.)
1063          * @param $to_lines array An array of strings.
1064          */
1065         function Diff($from_lines, $to_lines) {
1066                 $eng = new _DiffEngine;
1067                 $this->edits = $eng->diff($from_lines, $to_lines);
1068                 //$this->_check($from_lines, $to_lines);
1069         }
1070
1071         /**
1072          * Compute reversed Diff.
1073          *
1074          * SYNOPSIS:
1075          *
1076          *      $diff = new Diff($lines1, $lines2);
1077          *      $rev = $diff->reverse();
1078          * @return object A Diff object representing the inverse of the
1079          *                                original diff.
1080          */
1081         function reverse () {
1082                 $rev = $this;
1083                 $rev->edits = array();
1084                 foreach ($this->edits as $edit) {
1085                         $rev->edits[] = $edit->reverse();
1086                 }
1087                 return $rev;
1088         }
1089
1090         /**
1091          * Check for empty diff.
1092          *
1093          * @return bool True iff two sequences were identical.
1094          */
1095         function isEmpty () {
1096                 foreach ($this->edits as $edit) {
1097                         if ($edit->type != 'copy')
1098                                 return false;
1099                 }
1100                 return true;
1101         }
1102
1103         /**
1104          * Compute the length of the Longest Common Subsequence (LCS).
1105          *
1106          * This is mostly for diagnostic purposed.
1107          *
1108          * @return int The length of the LCS.
1109          */
1110         function lcs () {
1111                 $lcs = 0;
1112                 foreach ($this->edits as $edit) {
1113                         if ($edit->type == 'copy')
1114                                 $lcs += sizeof($edit->orig);
1115                 }
1116                 return $lcs;
1117         }
1118
1119         /**
1120          * Get the original set of lines.
1121          *
1122          * This reconstructs the $from_lines parameter passed to the
1123          * constructor.
1124          *
1125          * @return array The original sequence of strings.
1126          */
1127         function orig() {
1128                 $lines = array();
1129
1130                 foreach ($this->edits as $edit) {
1131                         if ($edit->orig)
1132                                 array_splice($lines, sizeof($lines), 0, $edit->orig);
1133                 }
1134                 return $lines;
1135         }
1136
1137         /**
1138          * Get the closing set of lines.
1139          *
1140          * This reconstructs the $to_lines parameter passed to the
1141          * constructor.
1142          *
1143          * @return array The sequence of strings.
1144          */
1145         function closing() {
1146                 $lines = array();
1147
1148                 foreach ($this->edits as $edit) {
1149                         if ($edit->closing)
1150                                 array_splice($lines, sizeof($lines), 0, $edit->closing);
1151                 }
1152                 return $lines;
1153         }
1154
1155         /**
1156          * Check a Diff for validity.
1157          *
1158          * This is here only for debugging purposes.
1159          */
1160         function _check ($from_lines, $to_lines) {
1161                 $fname = 'Diff::_check';
1162                 wfProfileIn( $fname );
1163                 if (serialize($from_lines) != serialize($this->orig()))
1164                         trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
1165                 if (serialize($to_lines) != serialize($this->closing()))
1166                         trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
1167
1168                 $rev = $this->reverse();
1169                 if (serialize($to_lines) != serialize($rev->orig()))
1170                         trigger_error("Reversed original doesn't match", E_USER_ERROR);
1171                 if (serialize($from_lines) != serialize($rev->closing()))
1172                         trigger_error("Reversed closing doesn't match", E_USER_ERROR);
1173
1174
1175                 $prevtype = 'none';
1176                 foreach ($this->edits as $edit) {
1177                         if ( $prevtype == $edit->type )
1178                                 trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
1179                         $prevtype = $edit->type;
1180                 }
1181
1182                 $lcs = $this->lcs();
1183                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
1184                 wfProfileOut( $fname );
1185         }
1186 }
1187
1188 /**
1189  * FIXME: bad name.
1190  * @todo document
1191  * @access private
1192  * @package MediaWiki
1193  * @subpackage DifferenceEngine
1194  */
1195 class MappedDiff extends Diff
1196 {
1197         /**
1198          * Constructor.
1199          *
1200          * Computes diff between sequences of strings.
1201          *
1202          * This can be used to compute things like
1203          * case-insensitve diffs, or diffs which ignore
1204          * changes in white-space.
1205          *
1206          * @param $from_lines array An array of strings.
1207          *      (Typically these are lines from a file.)
1208          *
1209          * @param $to_lines array An array of strings.
1210          *
1211          * @param $mapped_from_lines array This array should
1212          *      have the same size number of elements as $from_lines.
1213          *      The elements in $mapped_from_lines and
1214          *      $mapped_to_lines are what is actually compared
1215          *      when computing the diff.
1216          *
1217          * @param $mapped_to_lines array This array should
1218          *      have the same number of elements as $to_lines.
1219          */
1220         function MappedDiff($from_lines, $to_lines,
1221                                                 $mapped_from_lines, $mapped_to_lines) {
1222                 $fname = 'MappedDiff::MappedDiff';
1223                 wfProfileIn( $fname );
1224
1225                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
1226                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
1227
1228                 $this->Diff($mapped_from_lines, $mapped_to_lines);
1229
1230                 $xi = $yi = 0;
1231                 for ($i = 0; $i < sizeof($this->edits); $i++) {
1232                         $orig = &$this->edits[$i]->orig;
1233                         if (is_array($orig)) {
1234                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
1235                                 $xi += sizeof($orig);
1236                         }
1237
1238                         $closing = &$this->edits[$i]->closing;
1239                         if (is_array($closing)) {
1240                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
1241                                 $yi += sizeof($closing);
1242                         }
1243                 }
1244                 wfProfileOut( $fname );
1245         }
1246 }
1247
1248 /**
1249  * A class to format Diffs
1250  *
1251  * This class formats the diff in classic diff format.
1252  * It is intended that this class be customized via inheritance,
1253  * to obtain fancier outputs.
1254  * @todo document
1255  * @access private
1256  * @package MediaWiki
1257  * @subpackage DifferenceEngine
1258  */
1259 class DiffFormatter
1260 {
1261         /**
1262          * Number of leading context "lines" to preserve.
1263          *
1264          * This should be left at zero for this class, but subclasses
1265          * may want to set this to other values.
1266          */
1267         var $leading_context_lines = 0;
1268
1269         /**
1270          * Number of trailing context "lines" to preserve.
1271          *
1272          * This should be left at zero for this class, but subclasses
1273          * may want to set this to other values.
1274          */
1275         var $trailing_context_lines = 0;
1276
1277         /**
1278          * Format a diff.
1279          *
1280          * @param $diff object A Diff object.
1281          * @return string The formatted output.
1282          */
1283         function format($diff) {
1284                 $fname = 'DiffFormatter::format';
1285                 wfProfileIn( $fname );
1286
1287                 $xi = $yi = 1;
1288                 $block = false;
1289                 $context = array();
1290
1291                 $nlead = $this->leading_context_lines;
1292                 $ntrail = $this->trailing_context_lines;
1293
1294                 $this->_start_diff();
1295
1296                 foreach ($diff->edits as $edit) {
1297                         if ($edit->type == 'copy') {
1298                                 if (is_array($block)) {
1299                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1300                                                 $block[] = $edit;
1301                                         }
1302                                         else{
1303                                                 if ($ntrail) {
1304                                                         $context = array_slice($edit->orig, 0, $ntrail);
1305                                                         $block[] = new _DiffOp_Copy($context);
1306                                                 }
1307                                                 $this->_block($x0, $ntrail + $xi - $x0,
1308                                                                           $y0, $ntrail + $yi - $y0,
1309                                                                           $block);
1310                                                 $block = false;
1311                                         }
1312                                 }
1313                                 $context = $edit->orig;
1314                         }
1315                         else {
1316                                 if (! is_array($block)) {
1317                                         $context = array_slice($context, sizeof($context) - $nlead);
1318                                         $x0 = $xi - sizeof($context);
1319                                         $y0 = $yi - sizeof($context);
1320                                         $block = array();
1321                                         if ($context)
1322                                                 $block[] = new _DiffOp_Copy($context);
1323                                 }
1324                                 $block[] = $edit;
1325                         }
1326
1327                         if ($edit->orig)
1328                                 $xi += sizeof($edit->orig);
1329                         if ($edit->closing)
1330                                 $yi += sizeof($edit->closing);
1331                 }
1332
1333                 if (is_array($block))
1334                         $this->_block($x0, $xi - $x0,
1335                                                   $y0, $yi - $y0,
1336                                                   $block);
1337
1338                 $end = $this->_end_diff();
1339                 wfProfileOut( $fname );
1340                 return $end;
1341         }
1342
1343         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1344                 $fname = 'DiffFormatter::_block';
1345                 wfProfileIn( $fname );
1346                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1347                 foreach ($edits as $edit) {
1348                         if ($edit->type == 'copy')
1349                                 $this->_context($edit->orig);
1350                         elseif ($edit->type == 'add')
1351                                 $this->_added($edit->closing);
1352                         elseif ($edit->type == 'delete')
1353                                 $this->_deleted($edit->orig);
1354                         elseif ($edit->type == 'change')
1355                                 $this->_changed($edit->orig, $edit->closing);
1356                         else
1357                                 trigger_error('Unknown edit type', E_USER_ERROR);
1358                 }
1359                 $this->_end_block();
1360                 wfProfileOut( $fname );
1361         }
1362
1363         function _start_diff() {
1364                 ob_start();
1365         }
1366
1367         function _end_diff() {
1368                 $val = ob_get_contents();
1369                 ob_end_clean();
1370                 return $val;
1371         }
1372
1373         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1374                 if ($xlen > 1)
1375                         $xbeg .= "," . ($xbeg + $xlen - 1);
1376                 if ($ylen > 1)
1377                         $ybeg .= "," . ($ybeg + $ylen - 1);
1378
1379                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1380         }
1381
1382         function _start_block($header) {
1383                 echo $header;
1384         }
1385
1386         function _end_block() {
1387         }
1388
1389         function _lines($lines, $prefix = ' ') {
1390                 foreach ($lines as $line)
1391                         echo "$prefix $line\n";
1392         }
1393
1394         function _context($lines) {
1395                 $this->_lines($lines);
1396         }
1397
1398         function _added($lines) {
1399                 $this->_lines($lines, '>');
1400         }
1401         function _deleted($lines) {
1402                 $this->_lines($lines, '<');
1403         }
1404
1405         function _changed($orig, $closing) {
1406                 $this->_deleted($orig);
1407                 echo "---\n";
1408                 $this->_added($closing);
1409         }
1410 }
1411
1412
1413 /**
1414  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
1415  *
1416  */
1417
1418 define('NBSP', '&#160;');                       // iso-8859-x non-breaking space.
1419
1420 /**
1421  * @todo document
1422  * @access private
1423  * @package MediaWiki
1424  * @subpackage DifferenceEngine
1425  */
1426 class _HWLDF_WordAccumulator {
1427         function _HWLDF_WordAccumulator () {
1428                 $this->_lines = array();
1429                 $this->_line = '';
1430                 $this->_group = '';
1431                 $this->_tag = '';
1432         }
1433
1434         function _flushGroup ($new_tag) {
1435                 if ($this->_group !== '') {
1436                         if ($this->_tag == 'mark')
1437                                 $this->_line .= '<span class="diffchange">' .
1438                                         htmlspecialchars ( $this->_group ) . '</span>';
1439                         else
1440                                 $this->_line .= htmlspecialchars ( $this->_group );
1441                 }
1442                 $this->_group = '';
1443                 $this->_tag = $new_tag;
1444         }
1445
1446         function _flushLine ($new_tag) {
1447                 $this->_flushGroup($new_tag);
1448                 if ($this->_line != '')
1449                         array_push ( $this->_lines, $this->_line );
1450                 else
1451                         # make empty lines visible by inserting an NBSP
1452                         array_push ( $this->_lines, NBSP );
1453                 $this->_line = '';
1454         }
1455
1456         function addWords ($words, $tag = '') {
1457                 if ($tag != $this->_tag)
1458                         $this->_flushGroup($tag);
1459
1460                 foreach ($words as $word) {
1461                         // new-line should only come as first char of word.
1462                         if ($word == '')
1463                                 continue;
1464                         if ($word[0] == "\n") {
1465                                 $this->_flushLine($tag);
1466                                 $word = substr($word, 1);
1467                         }
1468                         assert(!strstr($word, "\n"));
1469                         $this->_group .= $word;
1470                 }
1471         }
1472
1473         function getLines() {
1474                 $this->_flushLine('~done');
1475                 return $this->_lines;
1476         }
1477 }
1478
1479 /**
1480  * @todo document
1481  * @access private
1482  * @package MediaWiki
1483  * @subpackage DifferenceEngine
1484  */
1485 class WordLevelDiff extends MappedDiff
1486 {
1487         function WordLevelDiff ($orig_lines, $closing_lines) {
1488                 $fname = 'WordLevelDiff::WordLevelDiff';
1489                 wfProfileIn( $fname );
1490
1491                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
1492                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
1493
1494                 $this->MappedDiff($orig_words, $closing_words,
1495                                                   $orig_stripped, $closing_stripped);
1496                 wfProfileOut( $fname );
1497         }
1498
1499         function _split($lines) {
1500                 $fname = 'WordLevelDiff::_split';
1501                 wfProfileIn( $fname );
1502
1503                 $words = array();
1504                 $stripped = array();
1505                 $first = true;
1506                 foreach ( $lines as $line ) {
1507                         # If the line is too long, just pretend the entire line is one big word
1508                         # This prevents resource exhaustion problems
1509                         if ( $first ) {
1510                                 $first = false;
1511                         } else {
1512                                 $words[] = "\n";
1513                                 $stripped[] = "\n";
1514                         }
1515                         if ( strlen( $line ) > MAX_DIFF_LINE ) {
1516                                 $words[] = $line;
1517                                 $stripped[] = $line;
1518                         } else {
1519                                 if (preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
1520                                         $line, $m))
1521                                 {
1522                                         $words = array_merge( $words, $m[0] );
1523                                         $stripped = array_merge( $stripped, $m[1] );
1524                                 }
1525                         }
1526                 }
1527                 wfProfileOut( $fname );
1528                 return array($words, $stripped);
1529         }
1530
1531         function orig () {
1532                 $fname = 'WordLevelDiff::orig';
1533                 wfProfileIn( $fname );
1534                 $orig = new _HWLDF_WordAccumulator;
1535
1536                 foreach ($this->edits as $edit) {
1537                         if ($edit->type == 'copy')
1538                                 $orig->addWords($edit->orig);
1539                         elseif ($edit->orig)
1540                                 $orig->addWords($edit->orig, 'mark');
1541                 }
1542                 $lines = $orig->getLines();
1543                 wfProfileOut( $fname );
1544                 return $lines;
1545         }
1546
1547         function closing () {
1548                 $fname = 'WordLevelDiff::closing';
1549                 wfProfileIn( $fname );
1550                 $closing = new _HWLDF_WordAccumulator;
1551
1552                 foreach ($this->edits as $edit) {
1553                         if ($edit->type == 'copy')
1554                                 $closing->addWords($edit->closing);
1555                         elseif ($edit->closing)
1556                                 $closing->addWords($edit->closing, 'mark');
1557                 }
1558                 $lines = $closing->getLines();
1559                 wfProfileOut( $fname );
1560                 return $lines;
1561         }
1562 }
1563
1564 /**
1565  *      Wikipedia Table style diff formatter.
1566  * @todo document
1567  * @access private
1568  * @package MediaWiki
1569  * @subpackage DifferenceEngine
1570  */
1571 class TableDiffFormatter extends DiffFormatter
1572 {
1573         function TableDiffFormatter() {
1574                 $this->leading_context_lines = 2;
1575                 $this->trailing_context_lines = 2;
1576         }
1577
1578         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
1579                 $l1 = wfMsg( 'lineno', $xbeg );
1580                 $l2 = wfMsg( 'lineno', $ybeg );
1581
1582                 $r = '<tr><td colspan="2" align="left"><strong>'.$l1."</strong></td>\n" .
1583                   '<td colspan="2" align="left"><strong>'.$l2."</strong></td></tr>\n";
1584                 return $r;
1585         }
1586
1587         function _start_block( $header ) {
1588                 global $wgOut;
1589                 echo $header;
1590         }
1591
1592         function _end_block() {
1593         }
1594
1595         function _lines( $lines, $prefix=' ', $color='white' ) {
1596         }
1597
1598         # HTML-escape parameter before calling this
1599         function addedLine( $line ) {
1600                 return "<td>+</td><td class='diff-addedline'>{$line}</td>";
1601         }
1602
1603         # HTML-escape parameter before calling this
1604         function deletedLine( $line ) {
1605                 return "<td>-</td><td class='diff-deletedline'>{$line}</td>";
1606         }
1607
1608         # HTML-escape parameter before calling this
1609         function contextLine( $line ) {
1610                 return "<td> </td><td class='diff-context'>{$line}</td>";
1611         }
1612
1613         function emptyLine() {
1614                 return '<td colspan="2">&nbsp;</td>';
1615         }
1616
1617         function _added( $lines ) {
1618                 foreach ($lines as $line) {
1619                         echo '<tr>' . $this->emptyLine() .
1620                                 $this->addedLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1621                 }
1622         }
1623
1624         function _deleted($lines) {
1625                 foreach ($lines as $line) {
1626                         echo '<tr>' . $this->deletedLine( htmlspecialchars ( $line ) ) .
1627                           $this->emptyLine() . "</tr>\n";
1628                 }
1629         }
1630
1631         function _context( $lines ) {
1632                 foreach ($lines as $line) {
1633                         echo '<tr>' .
1634                                 $this->contextLine( htmlspecialchars ( $line ) ) .
1635                                 $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1636                 }
1637         }
1638
1639         function _changed( $orig, $closing ) {
1640                 $fname = 'TableDiffFormatter::_changed';
1641                 wfProfileIn( $fname );
1642
1643                 $diff = new WordLevelDiff( $orig, $closing );
1644                 $del = $diff->orig();
1645                 $add = $diff->closing();
1646
1647                 # Notice that WordLevelDiff returns HTML-escaped output.
1648                 # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
1649
1650                 while ( $line = array_shift( $del ) ) {
1651                         $aline = array_shift( $add );
1652                         echo '<tr>' . $this->deletedLine( $line ) .
1653                                 $this->addedLine( $aline ) . "</tr>\n";
1654                 }
1655                 foreach ($add as $line) {       # If any leftovers
1656                         echo '<tr>' . $this->emptyLine() .
1657                                 $this->addedLine( $line ) . "</tr>\n";
1658                 }
1659                 wfProfileOut( $fname );
1660         }
1661 }
1662
1663 ?>