includes/DifferenceEngine.php

   1 <?php
   2 # See diff.doc
   3
   4 class DifferenceEngine {
   5         /* private */ var $mOldid, $mNewid;
   6         /* private */ var $mOldtitle, $mNewtitle, $mPagetitle;
   7         /* private */ var $mOldtext, $mNewtext;
   8         /* private */ var $mOldUser, $mNewUser;
   9         /* private */ var $mOldComment, $mNewComment;
  10         /* private */ var $mOldPage, $mNewPage;
  11         /* private */ var $mRcidMarkPatrolled;
  12
  13         function DifferenceEngine( $old, $new, $rcid = 0 )
  14         {
  15                 global $wgTitle;
  16                 if ( 'prev' == $new ) {
  17                         # Show diff between revision $old and the previous one.
  18                         # Get previous one from DB.
  19                         #
  20                         $this->mNewid = intval($old);
  21                         $dbr =& wfGetDB( DB_SLAVE );
  22                         $this->mOldid = $dbr->selectField( 'old', 'old_id',
  23                                 "old_title='" . $wgTitle->getDBkey() . "'" .
  24                                 ' AND old_namespace=' . $wgTitle->getNamespace() .
  25                                 " AND old_id<{$this->mNewid} ORDER BY old_id DESC" );
  26
  27                 } elseif ( 'next' == $new ) {
  28
  29                         # Show diff between revision $old and the previous one.
  30                         # Get previous one from DB.
  31                         #
  32                         $this->mOldid = intval($old);
  33                         $dbr =& wfGetDB( DB_SLAVE );
  34                         $this->mNewid = $dbr->selectField( 'old', 'old_id',
  35                                 "old_title='" . $wgTitle->getDBkey() . "'" .
  36                                 ' AND old_namespace=' . $wgTitle->getNamespace() .
  37                                 " AND old_id>{$this->mOldid} ORDER BY old_id " );
  38                         if ( false === $this->mNewid ) {
  39                                 # if no result, NewId points to the newest old revision. The only newer
  40                                 # revision is cur, which is "0".
  41                                 $this->mNewid = 0;
  42                         }
  43
  44                 } else {
  45
  46                         $this->mOldid = intval($old);
  47                         $this->mNewid = intval($new);
  48                 }
  49                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  50         }
  51
  52         function showDiffPage()
  53         {
  54                 global $wgUser, $wgTitle, $wgOut, $wgLang, $wgOnlySysopsCanPatrol, $wgUseRCPatrol;
  55                 $fname = 'DifferenceEngine::showDiffPage';
  56                 wfProfileIn( $fname );
  57
  58                 # mOldid is false if the difference engine is called with a "vague" query for
  59                 # a diff between a version V and its previous version V' AND the version V
  60                 # is the first version of that article. In that case, V' does not exist.
  61                 if ( $this->mOldid === false ) {
  62                         $this->showFirstRevision();
  63                         wfProfileOut( $fname );
  64                         return;
  65                 }
  66
  67                 $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
  68                   "{$this->mNewid})";
  69                 $mtext = wfMsg( 'missingarticle', $t );
  70
  71                 $wgOut->setArticleFlag( false );
  72                 if ( ! $this->loadText() ) {
  73                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
  74                         $wgOut->addHTML( $mtext );
  75                         wfProfileOut( $fname );
  76                         return;
  77                 }
  78                 $wgOut->suppressQuickbar();
  79
  80                 $oldTitle = $this->mOldPage->getPrefixedText();
  81                 $newTitle = $this->mNewPage->getPrefixedText();
  82                 if( $oldTitle == $newTitle ) {
  83                         $wgOut->setPageTitle( $newTitle );
  84                 } else {
  85                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
  86                 }
  87                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
  88                 $wgOut->setRobotpolicy( 'noindex,follow' );
  89
  90                 if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
  91                         $wgOut->loginToUse();
  92                         $wgOut->output();
  93                         wfProfileOut( $fname );
  94                         exit;
  95                 }
  96
  97                 $sk = $wgUser->getSkin();
  98                 $talk = $wgLang->getNsText( NS_TALK );
  99                 $contribs = wfMsg( 'contribslink' );
 100
 101                 $this->mOldComment = $sk->formatComment($this->mOldComment);
 102                 $this->mNewComment = $sk->formatComment($this->mNewComment);
 103
 104                 $oldUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 105                 $newUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mNewUser ), $this->mNewUser );
 106                 $oldUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ), $talk );
 107                 $newUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mNewUser ), $talk );
 108                 $oldContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 109                         'target=' . urlencode($this->mOldUser) );
 110                 $newContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 111                         'target=' . urlencode($this->mNewUser) );
 112                 if ( !$this->mNewid && $wgUser->isSysop() ) {
 113                         $rollback = '&nbsp;&nbsp;&nbsp;<strong>[' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'rollbacklink' ),
 114                                 'action=rollback&from=' . urlencode($this->mNewUser) ) . ']</strong>';
 115                 } else {
 116                         $rollback = '';
 117                 }
 118                 if ( $wgUseRCPatrol && $this->mRcidMarkPatrolled != 0 && $wgUser->getID() != 0 &&
 119                      ( $wgUser->isSysop() || !$wgOnlySysopsCanPatrol ) )
 120                 {
 121                         $patrol = ' [' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'markaspatrolleddiff' ),
 122                                 "action=markpatrolled&rcid={$this->mRcidMarkPatrolled}" ) . ']';
 123                 } else {
 124                         $patrol = '';
 125                 }
 126
 127                 $prevlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'previousdiff' ), 'diff=prev&oldid='.$this->mOldid );
 128                 if ( $this->mNewid == 0 ) {
 129                         $nextlink = '';
 130                 } else {
 131                         $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
 132                 }
 133
 134                 $oldHeader = "<strong>{$this->mOldtitle}</strong><br />$oldUserLink " .
 135                         "($oldUTLink | $oldContribs)<br />" . $this->mOldComment .
 136                         '<br />' . $prevlink;
 137                 $newHeader = "<strong>{$this->mNewtitle}</strong><br />$newUserLink " .
 138                         "($newUTLink | $newContribs) $rollback<br />" . $this->mNewComment .
 139                         '<br />' . $nextlink . $patrol;
 140
 141                 DifferenceEngine::showDiff( $this->mOldtext, $this->mNewtext,
 142                   $oldHeader, $newHeader );
 143                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 144                 $wgOut->addWikiText( $this->mNewtext );
 145
 146                 wfProfileOut( $fname );
 147         }
 148
 149         # Show the first revision of an article. Uses normal diff headers in contrast to normal
 150         # "old revision" display style.
 151         #
 152         function showFirstRevision()
 153         {
 154                 global $wgOut, $wgTitle, $wgUser, $wgLang;
 155
 156                 $fname = 'DifferenceEngine::showFirstRevision';
 157                 wfProfileIn( $fname );
 158
 159
 160                 $this->mOldid = $this->mNewid; # hack to make loadText() work.
 161
 162                 # Get article text from the DB
 163                 #
 164                 if ( ! $this->loadText() ) {
 165                         $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 166                           "{$this->mNewid})";
 167                         $mtext = wfMsg( 'missingarticle', $t );
 168                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 169                         $wgOut->addHTML( $mtext );
 170                         wfProfileOut( $fname );
 171                         return;
 172                 }
 173
 174                 # Check if user is allowed to look at this page. If not, bail out.
 175                 #
 176                 if ( !( $this->mOldPage->userCanRead() ) ) {
 177                         $wgOut->loginToUse();
 178                         $wgOut->output();
 179                         wfProfileOut( $fname );
 180                         exit;
 181                 }
 182
 183                 # Prepare the header box
 184                 #
 185                 $sk = $wgUser->getSkin();
 186
 187                 $uTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ),  $wgLang->getNsText( NS_TALK ) );
 188                 $userLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 189                 $contribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), wfMsg( 'contribslink' ),
 190                         'target=' . urlencode($this->mOldUser) );
 191                 $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
 192                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />$userLink " .
 193                         "($uTLink | $contribs)<br />" . $this->mOldComment .
 194                         '<br />' . $nextlink. "</div>\n";
 195
 196                 $wgOut->addHTML( $header );
 197
 198                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 199                 $wgOut->setRobotpolicy( 'noindex,follow' );
 200
 201
 202                 # Show current revision
 203                 #
 204                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 205                 $wgOut->addWikiText( $this->mNewtext );
 206
 207                 wfProfileOut( $fname );
 208         }
 209
 210         function showDiff( $otext, $ntext, $otitle, $ntitle )
 211         {
 212                 global $wgOut, $wgUseExternalDiffEngine;
 213
 214                 $otext = str_replace( "\r\n", "\n", $otext );
 215                 $ntext = str_replace( "\r\n", "\n", $ntext );
 216
 217
 218                         $wgOut->addHTML( "<table border='0' width='98%'
 219 cellpadding='0' cellspacing='4px' class='diff'><tr>
 220 <td colspan='2' width='50%' align='center' class='diff-otitle'>
 221 {$otitle}</td>
 222 <td colspan='2' width='50%' align='center' class='diff-ntitle'>
 223 {$ntitle}</td>
 224 </tr>\n" );
 225                 if ( $wgUseExternalDiffEngine ) {
 226                         dl('php_wikidiff.so');
 227                         $wgOut->addHTML( wikidiff_do_diff( $otext, $ntext, 2) );
 228                 } else {
 229                         $ota = explode( "\n", $otext);
 230                         $nta = explode( "\n", $ntext);
 231                         $diffs = new Diff( $ota, $nta );
 232                         $formatter = new TableDiffFormatter();
 233                         $formatter->format( $diffs );
 234                 }
 235                 $wgOut->addHTML( "</table>\n" );
 236         }
 237
 238         # Load the text of the articles to compare.  If newid is 0, then compare
 239         # the old article in oldid to the current article; if oldid is 0, then
 240         # compare the current article to the immediately previous one (ignoring
 241         # the value of newid).
 242         #
 243         function loadText()
 244         {
 245                 global $wgTitle, $wgOut, $wgLang;
 246                 $fname = 'DifferenceEngine::loadText';
 247
 248                 $dbr =& wfGetDB( DB_SLAVE );
 249                 if ( 0 == $this->mNewid || 0 == $this->mOldid ) {
 250                         $wgOut->setArticleFlag( true );
 251                         $newLink = $wgTitle->getLocalUrl();
 252                         $this->mPagetitle = wfMsg( 'currentrev' );
 253                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 254                         $id = $wgTitle->getArticleID();
 255
 256                         $s = $dbr->getArray( 'cur', array( 'cur_text', 'cur_user_text', 'cur_comment' ),
 257                                 array( 'cur_id' => $id ), $fname );
 258                         if ( $s === false ) {
 259                                 return false;
 260                         }
 261
 262                         $this->mNewPage = &$wgTitle;
 263                         $this->mNewtext = $s->cur_text;
 264                         $this->mNewUser = $s->cur_user_text;
 265                         $this->mNewComment = $s->cur_comment;
 266                 } else {
 267                         $s = $dbr->getArray( 'old', array( 'old_namespace','old_title','old_timestamp', 'old_text',
 268                                 'old_flags','old_user_text','old_comment' ), array( 'old_id' => $this->mNewid ), $fname );
 269
 270                         if ( $s === false ) {
 271                                 return false;
 272                         }
 273
 274                         $this->mNewtext = Article::getRevisionText( $s );
 275
 276                         $t = $wgLang->timeanddate( $s->old_timestamp, true );
 277                         $this->mNewPage = Title::MakeTitle( $s->old_namespace, $s->old_title );
 278                         $newLink = $wgTitle->getLocalUrl ('oldid=' . $this->mNewid);
 279                         $this->mPagetitle = wfMsg( 'revisionasof', $t );
 280                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 281                         $this->mNewUser = $s->old_user_text;
 282                         $this->mNewComment = $s->old_comment;
 283                 }
 284                 if ( 0 == $this->mOldid ) {
 285                         $s = $dbr->getArray( 'old',
 286                                 array( 'old_namespace','old_title','old_timestamp','old_text', 'old_flags','old_user_text','old_comment' ),
 287                                 array( /* WHERE */
 288                                         'old_namespace' => $this->mNewPage->getNamespace(),
 289                                         'old_title' => $this->mNewPage->getDBkey()
 290                                 ), $fname, array( 'ORDER BY' => 'inverse_timestamp', 'USE INDEX' => 'name_title_timestamp' )
 291                         );
 292                 } else {
 293                         $s = $dbr->getArray( 'old',
 294                                 array( 'old_namespace','old_title','old_timestamp','old_text','old_flags','old_user_text','old_comment'),
 295                                 array( 'old_id' => $this->mOldid ),
 296                                 $fname
 297                         );
 298                 }
 299                 if ( $s === false ) {
 300                         return false;
 301                 }
 302                 $this->mOldPage = Title::MakeTitle( $s->old_namespace, $s->old_title );
 303                 $this->mOldtext = Article::getRevisionText( $s );
 304
 305                 $t = $wgLang->timeanddate( $s->old_timestamp, true );
 306                 $oldLink = $this->mOldPage->getLocalUrl ('oldid=' . $this->mOldid);
 307                 $this->mOldtitle = "<a href='$oldLink'>" . wfMsg( 'revisionasof', $t ) . '</a>';
 308                 $this->mOldUser = $s->old_user_text;
 309                 $this->mOldComment = $s->old_comment;
 310
 311                 return true;
 312         }
 313 }
 314
 315 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
 316 //
 317 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 318 // You may copy this code freely under the conditions of the GPL.
 319 //
 320
 321 define('USE_ASSERTS', function_exists('assert'));
 322
 323 class _DiffOp {
 324         var $type;
 325         var $orig;
 326         var $closing;
 327
 328         function reverse() {
 329                 trigger_error('pure virtual', E_USER_ERROR);
 330         }
 331
 332         function norig() {
 333                 return $this->orig ? sizeof($this->orig) : 0;
 334         }
 335
 336         function nclosing() {
 337                 return $this->closing ? sizeof($this->closing) : 0;
 338         }
 339 }
 340
 341 class _DiffOp_Copy extends _DiffOp {
 342         var $type = 'copy';
 343
 344         function _DiffOp_Copy ($orig, $closing = false) {
 345                 if (!is_array($closing))
 346                         $closing = $orig;
 347                 $this->orig = $orig;
 348                 $this->closing = $closing;
 349         }
 350
 351         function reverse() {
 352                 return new _DiffOp_Copy($this->closing, $this->orig);
 353         }
 354 }
 355
 356 class _DiffOp_Delete extends _DiffOp {
 357         var $type = 'delete';
 358
 359         function _DiffOp_Delete ($lines) {
 360                 $this->orig = $lines;
 361                 $this->closing = false;
 362         }
 363
 364         function reverse() {
 365                 return new _DiffOp_Add($this->orig);
 366         }
 367 }
 368
 369 class _DiffOp_Add extends _DiffOp {
 370         var $type = 'add';
 371
 372         function _DiffOp_Add ($lines) {
 373                 $this->closing = $lines;
 374                 $this->orig = false;
 375         }
 376
 377         function reverse() {
 378                 return new _DiffOp_Delete($this->closing);
 379         }
 380 }
 381
 382 class _DiffOp_Change extends _DiffOp {
 383         var $type = 'change';
 384
 385         function _DiffOp_Change ($orig, $closing) {
 386                 $this->orig = $orig;
 387                 $this->closing = $closing;
 388         }
 389
 390         function reverse() {
 391                 return new _DiffOp_Change($this->closing, $this->orig);
 392         }
 393 }
 394
 395
 396 /**
 397  * Class used internally by Diff to actually compute the diffs.
 398  *
 399  * The algorithm used here is mostly lifted from the perl module
 400  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
 401  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
 402  *
 403  * More ideas are taken from:
 404  *       http://www.ics.uci.edu/~eppstein/161/960229.html
 405  *
 406  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
 407  * diffutils-2.7, which can be found at:
 408  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
 409  *
 410  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
 411  * are my own.
 412  *
 413  * @author Geoffrey T. Dairiki
 414  * @access private
 415  */
 416 class _DiffEngine
 417 {
 418         function diff ($from_lines, $to_lines) {
 419                 $n_from = sizeof($from_lines);
 420                 $n_to = sizeof($to_lines);
 421
 422                 $this->xchanged = $this->ychanged = array();
 423                 $this->xv = $this->yv = array();
 424                 $this->xind = $this->yind = array();
 425                 unset($this->seq);
 426                 unset($this->in_seq);
 427                 unset($this->lcs);
 428
 429                 // Skip leading common lines.
 430                 for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
 431                         if ($from_lines[$skip] != $to_lines[$skip])
 432                                 break;
 433                         $this->xchanged[$skip] = $this->ychanged[$skip] = false;
 434                 }
 435                 // Skip trailing common lines.
 436                 $xi = $n_from; $yi = $n_to;
 437                 for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
 438                         if ($from_lines[$xi] != $to_lines[$yi])
 439                                 break;
 440                         $this->xchanged[$xi] = $this->ychanged[$yi] = false;
 441                 }
 442
 443                 // Ignore lines which do not exist in both files.
 444                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
 445                         $xhash[$from_lines[$xi]] = 1;
 446                 for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
 447                         $line = $to_lines[$yi];
 448                         if ( ($this->ychanged[$yi] = empty($xhash[$line])) )
 449                                 continue;
 450                         $yhash[$line] = 1;
 451                         $this->yv[] = $line;
 452                         $this->yind[] = $yi;
 453                 }
 454                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 455                         $line = $from_lines[$xi];
 456                         if ( ($this->xchanged[$xi] = empty($yhash[$line])) )
 457                                 continue;
 458                         $this->xv[] = $line;
 459                         $this->xind[] = $xi;
 460                 }
 461
 462                 // Find the LCS.
 463                 $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
 464
 465                 // Merge edits when possible
 466                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
 467                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
 468
 469                 // Compute the edit operations.
 470                 $edits = array();
 471                 $xi = $yi = 0;
 472                 while ($xi < $n_from || $yi < $n_to) {
 473                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
 474                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
 475
 476                         // Skip matching "snake".
 477                         $copy = array();
 478                         while ( $xi < $n_from && $yi < $n_to
 479                                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
 480                                 $copy[] = $from_lines[$xi++];
 481                                 ++$yi;
 482                         }
 483                         if ($copy)
 484                                 $edits[] = new _DiffOp_Copy($copy);
 485
 486                         // Find deletes & adds.
 487                         $delete = array();
 488                         while ($xi < $n_from && $this->xchanged[$xi])
 489                                 $delete[] = $from_lines[$xi++];
 490
 491                         $add = array();
 492                         while ($yi < $n_to && $this->ychanged[$yi])
 493                                 $add[] = $to_lines[$yi++];
 494
 495                         if ($delete && $add)
 496                                 $edits[] = new _DiffOp_Change($delete, $add);
 497                         elseif ($delete)
 498                                 $edits[] = new _DiffOp_Delete($delete);
 499                         elseif ($add)
 500                                 $edits[] = new _DiffOp_Add($add);
 501                 }
 502                 return $edits;
 503         }
 504
 505
 506         /* Divide the Largest Common Subsequence (LCS) of the sequences
 507          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
 508          * sized segments.
 509          *
 510          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
 511          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
 512          * sub sequences.  The first sub-sequence is contained in [X0, X1),
 513          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
 514          * that (X0, Y0) == (XOFF, YOFF) and
 515          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
 516          *
 517          * This function assumes that the first lines of the specified portions
 518          * of the two files do not match, and likewise that the last lines do not
 519          * match.  The caller must trim matching lines from the beginning and end
 520          * of the portions it is going to specify.
 521          */
 522         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
 523         $flip = false;
 524
 525         if ($xlim - $xoff > $ylim - $yoff) {
 526                 // Things seems faster (I'm not sure I understand why)
 527                         // when the shortest sequence in X.
 528                         $flip = true;
 529                 list ($xoff, $xlim, $yoff, $ylim)
 530                 = array( $yoff, $ylim, $xoff, $xlim);
 531                 }
 532
 533         if ($flip)
 534                 for ($i = $ylim - 1; $i >= $yoff; $i--)
 535                 $ymatches[$this->xv[$i]][] = $i;
 536         else
 537                 for ($i = $ylim - 1; $i >= $yoff; $i--)
 538                 $ymatches[$this->yv[$i]][] = $i;
 539
 540         $this->lcs = 0;
 541         $this->seq[0]= $yoff - 1;
 542         $this->in_seq = array();
 543         $ymids[0] = array();
 544
 545         $numer = $xlim - $xoff + $nchunks - 1;
 546         $x = $xoff;
 547         for ($chunk = 0; $chunk < $nchunks; $chunk++) {
 548                 if ($chunk > 0)
 549                 for ($i = 0; $i <= $this->lcs; $i++)
 550                         $ymids[$i][$chunk-1] = $this->seq[$i];
 551
 552                 $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
 553                 for ( ; $x < $x1; $x++) {
 554                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
 555                                 if (empty($ymatches[$line]))
 556                         continue;
 557                 $matches = $ymatches[$line];
 558                                 reset($matches);
 559                 while (list ($junk, $y) = each($matches))
 560                         if (empty($this->in_seq[$y])) {
 561                         $k = $this->_lcs_pos($y);
 562                         USE_ASSERTS && assert($k > 0);
 563                         $ymids[$k] = $ymids[$k-1];
 564                         break;
 565                                         }
 566                 while (list ($junk, $y) = each($matches)) {
 567                         if ($y > $this->seq[$k-1]) {
 568                         USE_ASSERTS && assert($y < $this->seq[$k]);
 569                         // Optimization: this is a common case:
 570                         //      next match is just replacing previous match.
 571                         $this->in_seq[$this->seq[$k]] = false;
 572                         $this->seq[$k] = $y;
 573                         $this->in_seq[$y] = 1;
 574                                         }
 575                         else if (empty($this->in_seq[$y])) {
 576                         $k = $this->_lcs_pos($y);
 577                         USE_ASSERTS && assert($k > 0);
 578                         $ymids[$k] = $ymids[$k-1];
 579                                         }
 580                                 }
 581                         }
 582                 }
 583
 584         $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
 585         $ymid = $ymids[$this->lcs];
 586         for ($n = 0; $n < $nchunks - 1; $n++) {
 587                 $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
 588                 $y1 = $ymid[$n] + 1;
 589                 $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
 590                 }
 591         $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
 592
 593         return array($this->lcs, $seps);
 594         }
 595
 596         function _lcs_pos ($ypos) {
 597         $end = $this->lcs;
 598         if ($end == 0 || $ypos > $this->seq[$end]) {
 599                 $this->seq[++$this->lcs] = $ypos;
 600                 $this->in_seq[$ypos] = 1;
 601                 return $this->lcs;
 602                 }
 603
 604         $beg = 1;
 605         while ($beg < $end) {
 606                 $mid = (int)(($beg + $end) / 2);
 607                 if ( $ypos > $this->seq[$mid] )
 608                 $beg = $mid + 1;
 609                 else
 610                 $end = $mid;
 611                 }
 612
 613         USE_ASSERTS && assert($ypos != $this->seq[$end]);
 614
 615         $this->in_seq[$this->seq[$end]] = false;
 616         $this->seq[$end] = $ypos;
 617         $this->in_seq[$ypos] = 1;
 618         return $end;
 619         }
 620
 621         /* Find LCS of two sequences.
 622          *
 623          * The results are recorded in the vectors $this->{x,y}changed[], by
 624          * storing a 1 in the element for each line that is an insertion
 625          * or deletion (ie. is not in the LCS).
 626          *
 627          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
 628          *
 629          * Note that XLIM, YLIM are exclusive bounds.
 630          * All line numbers are origin-0 and discarded lines are not counted.
 631          */
 632         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
 633         // Slide down the bottom initial diagonal.
 634         while ($xoff < $xlim && $yoff < $ylim
 635                            && $this->xv[$xoff] == $this->yv[$yoff]) {
 636                 ++$xoff;
 637                 ++$yoff;
 638                 }
 639
 640         // Slide up the top initial diagonal.
 641         while ($xlim > $xoff && $ylim > $yoff
 642                            && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
 643                 --$xlim;
 644                 --$ylim;
 645                 }
 646
 647         if ($xoff == $xlim || $yoff == $ylim)
 648                 $lcs = 0;
 649         else {
 650                 // This is ad hoc but seems to work well.
 651                 //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
 652                 //$nchunks = max(2,min(8,(int)$nchunks));
 653                 $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
 654                 list ($lcs, $seps)
 655                 = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
 656                 }
 657
 658         if ($lcs == 0) {
 659                 // X and Y sequences have no common subsequence:
 660                 // mark all changed.
 661                 while ($yoff < $ylim)
 662                 $this->ychanged[$this->yind[$yoff++]] = 1;
 663                 while ($xoff < $xlim)
 664                 $this->xchanged[$this->xind[$xoff++]] = 1;
 665                 }
 666         else {
 667                 // Use the partitions to split this problem into subproblems.
 668                 reset($seps);
 669                 $pt1 = $seps[0];
 670                 while ($pt2 = next($seps)) {
 671                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
 672                 $pt1 = $pt2;
 673                         }
 674                 }
 675         }
 676
 677         /* Adjust inserts/deletes of identical lines to join changes
 678          * as much as possible.
 679          *
 680          * We do something when a run of changed lines include a
 681          * line at one end and has an excluded, identical line at the other.
 682          * We are free to choose which identical line is included.
 683          * `compareseq' usually chooses the one at the beginning,
 684          * but usually it is cleaner to consider the following identical line
 685          * to be the "change".
 686          *
 687          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
 688          */
 689         function _shift_boundaries ($lines, &$changed, $other_changed) {
 690         $i = 0;
 691         $j = 0;
 692
 693         USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
 694         $len = sizeof($lines);
 695         $other_len = sizeof($other_changed);
 696
 697         while (1) {
 698                 /*
 699                  * Scan forwards to find beginning of another run of changes.
 700                  * Also keep track of the corresponding point in the other file.
 701                  *
 702                  * Throughout this code, $i and $j are adjusted together so that
 703                  * the first $i elements of $changed and the first $j elements
 704                  * of $other_changed both contain the same number of zeros
 705                  * (unchanged lines).
 706                  * Furthermore, $j is always kept so that $j == $other_len or
 707                  * $other_changed[$j] == false.
 708                  */
 709                 while ($j < $other_len && $other_changed[$j])
 710                 $j++;
 711
 712                 while ($i < $len && ! $changed[$i]) {
 713                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 714                 $i++; $j++;
 715                 while ($j < $other_len && $other_changed[$j])
 716                         $j++;
 717                         }
 718
 719                 if ($i == $len)
 720                 break;
 721
 722                 $start = $i;
 723
 724                 // Find the end of this run of changes.
 725                 while (++$i < $len && $changed[$i])
 726                 continue;
 727
 728                 do {
 729                 /*
 730                  * Record the length of this run of changes, so that
 731                  * we can later determine whether the run has grown.
 732                  */
 733                 $runlength = $i - $start;
 734
 735                 /*
 736                  * Move the changed region back, so long as the
 737                  * previous unchanged line matches the last changed one.
 738                  * This merges with previous changed regions.
 739                  */
 740                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
 741                         $changed[--$start] = 1;
 742                         $changed[--$i] = false;
 743                         while ($start > 0 && $changed[$start - 1])
 744                         $start--;
 745                         USE_ASSERTS && assert('$j > 0');
 746                         while ($other_changed[--$j])
 747                         continue;
 748                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 749                                 }
 750
 751                 /*
 752                  * Set CORRESPONDING to the end of the changed run, at the last
 753                  * point where it corresponds to a changed run in the other file.
 754                  * CORRESPONDING == LEN means no such point has been found.
 755                  */
 756                 $corresponding = $j < $other_len ? $i : $len;
 757
 758                 /*
 759                  * Move the changed region forward, so long as the
 760                  * first changed line matches the following unchanged one.
 761                  * This merges with following changed regions.
 762                  * Do this second, so that if there are no merges,
 763                  * the changed region is moved forward as far as possible.
 764                  */
 765                 while ($i < $len && $lines[$start] == $lines[$i]) {
 766                         $changed[$start++] = false;
 767                         $changed[$i++] = 1;
 768                         while ($i < $len && $changed[$i])
 769                         $i++;
 770
 771                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 772                         $j++;
 773                         if ($j < $other_len && $other_changed[$j]) {
 774                         $corresponding = $i;
 775                         while ($j < $other_len && $other_changed[$j])
 776                                 $j++;
 777                                         }
 778                                 }
 779                         } while ($runlength != $i - $start);
 780
 781                 /*
 782                  * If possible, move the fully-merged run of changes
 783                  * back to a corresponding run in the other file.
 784                  */
 785                 while ($corresponding < $i) {
 786                 $changed[--$start] = 1;
 787                 $changed[--$i] = 0;
 788                 USE_ASSERTS && assert('$j > 0');
 789                 while ($other_changed[--$j])
 790                         continue;
 791                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 792                         }
 793                 }
 794         }
 795 }
 796
 797 /**
 798  * Class representing a 'diff' between two sequences of strings.
 799  */
 800 class Diff
 801 {
 802         var $edits;
 803
 804         /**
 805          * Constructor.
 806          * Computes diff between sequences of strings.
 807          *
 808          * @param $from_lines array An array of strings.
 809          *                (Typically these are lines from a file.)
 810          * @param $to_lines array An array of strings.
 811          */
 812         function Diff($from_lines, $to_lines) {
 813                 $eng = new _DiffEngine;
 814                 $this->edits = $eng->diff($from_lines, $to_lines);
 815                 //$this->_check($from_lines, $to_lines);
 816         }
 817
 818         /**
 819          * Compute reversed Diff.
 820          *
 821          * SYNOPSIS:
 822          *
 823          *      $diff = new Diff($lines1, $lines2);
 824          *      $rev = $diff->reverse();
 825          * @return object A Diff object representing the inverse of the
 826          *                                original diff.
 827          */
 828         function reverse () {
 829         $rev = $this;
 830                 $rev->edits = array();
 831                 foreach ($this->edits as $edit) {
 832                         $rev->edits[] = $edit->reverse();
 833                 }
 834         return $rev;
 835         }
 836
 837         /**
 838          * Check for empty diff.
 839          *
 840          * @return bool True iff two sequences were identical.
 841          */
 842         function isEmpty () {
 843                 foreach ($this->edits as $edit) {
 844                         if ($edit->type != 'copy')
 845                                 return false;
 846                 }
 847                 return true;
 848         }
 849
 850         /**
 851          * Compute the length of the Longest Common Subsequence (LCS).
 852          *
 853          * This is mostly for diagnostic purposed.
 854          *
 855          * @return int The length of the LCS.
 856          */
 857         function lcs () {
 858         $lcs = 0;
 859                 foreach ($this->edits as $edit) {
 860                         if ($edit->type == 'copy')
 861                                 $lcs += sizeof($edit->orig);
 862                 }
 863         return $lcs;
 864         }
 865
 866         /**
 867          * Get the original set of lines.
 868          *
 869          * This reconstructs the $from_lines parameter passed to the
 870          * constructor.
 871          *
 872          * @return array The original sequence of strings.
 873          */
 874         function orig() {
 875                 $lines = array();
 876
 877                 foreach ($this->edits as $edit) {
 878                         if ($edit->orig)
 879                                 array_splice($lines, sizeof($lines), 0, $edit->orig);
 880                 }
 881                 return $lines;
 882         }
 883
 884         /**
 885          * Get the closing set of lines.
 886          *
 887          * This reconstructs the $to_lines parameter passed to the
 888          * constructor.
 889          *
 890          * @return array The sequence of strings.
 891          */
 892         function closing() {
 893                 $lines = array();
 894
 895                 foreach ($this->edits as $edit) {
 896                         if ($edit->closing)
 897                                 array_splice($lines, sizeof($lines), 0, $edit->closing);
 898                 }
 899                 return $lines;
 900         }
 901
 902         /**
 903          * Check a Diff for validity.
 904          *
 905          * This is here only for debugging purposes.
 906          */
 907         function _check ($from_lines, $to_lines) {
 908                 if (serialize($from_lines) != serialize($this->orig()))
 909                         trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
 910                 if (serialize($to_lines) != serialize($this->closing()))
 911                         trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
 912
 913                 $rev = $this->reverse();
 914                 if (serialize($to_lines) != serialize($rev->orig()))
 915                         trigger_error("Reversed original doesn't match", E_USER_ERROR);
 916                 if (serialize($from_lines) != serialize($rev->closing()))
 917                         trigger_error("Reversed closing doesn't match", E_USER_ERROR);
 918
 919
 920                 $prevtype = 'none';
 921                 foreach ($this->edits as $edit) {
 922                         if ( $prevtype == $edit->type )
 923                                 trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
 924                         $prevtype = $edit->type;
 925                 }
 926
 927                 $lcs = $this->lcs();
 928                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
 929         }
 930 }
 931
 932 /**
 933  * FIXME: bad name.
 934  */
 935 class MappedDiff
 936 extends Diff
 937 {
 938         /**
 939          * Constructor.
 940          *
 941          * Computes diff between sequences of strings.
 942          *
 943          * This can be used to compute things like
 944          * case-insensitve diffs, or diffs which ignore
 945          * changes in white-space.
 946          *
 947          * @param $from_lines array An array of strings.
 948          *      (Typically these are lines from a file.)
 949          *
 950          * @param $to_lines array An array of strings.
 951          *
 952          * @param $mapped_from_lines array This array should
 953          *      have the same size number of elements as $from_lines.
 954          *      The elements in $mapped_from_lines and
 955          *      $mapped_to_lines are what is actually compared
 956          *      when computing the diff.
 957          *
 958          * @param $mapped_to_lines array This array should
 959          *      have the same number of elements as $to_lines.
 960          */
 961         function MappedDiff($from_lines, $to_lines,
 962                                                 $mapped_from_lines, $mapped_to_lines) {
 963
 964                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
 965                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
 966
 967                 $this->Diff($mapped_from_lines, $mapped_to_lines);
 968
 969                 $xi = $yi = 0;
 970                 for ($i = 0; $i < sizeof($this->edits); $i++) {
 971                         $orig = &$this->edits[$i]->orig;
 972                         if (is_array($orig)) {
 973                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
 974                                 $xi += sizeof($orig);
 975                         }
 976
 977                         $closing = &$this->edits[$i]->closing;
 978                         if (is_array($closing)) {
 979                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
 980                                 $yi += sizeof($closing);
 981                         }
 982                 }
 983         }
 984 }
 985
 986 /**
 987  * A class to format Diffs
 988  *
 989  * This class formats the diff in classic diff format.
 990  * It is intended that this class be customized via inheritance,
 991  * to obtain fancier outputs.
 992  */
 993 class DiffFormatter
 994 {
 995         /**
 996          * Number of leading context "lines" to preserve.
 997          *
 998          * This should be left at zero for this class, but subclasses
 999          * may want to set this to other values.
1000          */
1001         var $leading_context_lines = 0;
1002
1003         /**
1004          * Number of trailing context "lines" to preserve.
1005          *
1006          * This should be left at zero for this class, but subclasses
1007          * may want to set this to other values.
1008          */
1009         var $trailing_context_lines = 0;
1010
1011         /**
1012          * Format a diff.
1013          *
1014          * @param $diff object A Diff object.
1015          * @return string The formatted output.
1016          */
1017         function format($diff) {
1018
1019                 $xi = $yi = 1;
1020                 $block = false;
1021                 $context = array();
1022
1023                 $nlead = $this->leading_context_lines;
1024                 $ntrail = $this->trailing_context_lines;
1025
1026                 $this->_start_diff();
1027
1028                 foreach ($diff->edits as $edit) {
1029                         if ($edit->type == 'copy') {
1030                                 if (is_array($block)) {
1031                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1032                                                 $block[] = $edit;
1033                                         }
1034                                         else{
1035                                                 if ($ntrail) {
1036                                                         $context = array_slice($edit->orig, 0, $ntrail);
1037                                                         $block[] = new _DiffOp_Copy($context);
1038                                                 }
1039                                                 $this->_block($x0, $ntrail + $xi - $x0,
1040                                                                           $y0, $ntrail + $yi - $y0,
1041                                                                           $block);
1042                                                 $block = false;
1043                                         }
1044                                 }
1045                                 $context = $edit->orig;
1046                         }
1047                         else {
1048                                 if (! is_array($block)) {
1049                                         $context = array_slice($context, sizeof($context) - $nlead);
1050                                         $x0 = $xi - sizeof($context);
1051                                         $y0 = $yi - sizeof($context);
1052                                         $block = array();
1053                                         if ($context)
1054                                                 $block[] = new _DiffOp_Copy($context);
1055                                 }
1056                                 $block[] = $edit;
1057                         }
1058
1059                         if ($edit->orig)
1060                                 $xi += sizeof($edit->orig);
1061                         if ($edit->closing)
1062                                 $yi += sizeof($edit->closing);
1063                 }
1064
1065                 if (is_array($block))
1066                         $this->_block($x0, $xi - $x0,
1067                                                   $y0, $yi - $y0,
1068                                                   $block);
1069
1070                 return $this->_end_diff();
1071         }
1072
1073         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1074                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1075                 foreach ($edits as $edit) {
1076                         if ($edit->type == 'copy')
1077                                 $this->_context($edit->orig);
1078                         elseif ($edit->type == 'add')
1079                                 $this->_added($edit->closing);
1080                         elseif ($edit->type == 'delete')
1081                                 $this->_deleted($edit->orig);
1082                         elseif ($edit->type == 'change')
1083                                 $this->_changed($edit->orig, $edit->closing);
1084                         else
1085                                 trigger_error('Unknown edit type', E_USER_ERROR);
1086                 }
1087                 $this->_end_block();
1088         }
1089
1090         function _start_diff() {
1091                 ob_start();
1092         }
1093
1094         function _end_diff() {
1095                 $val = ob_get_contents();
1096                 ob_end_clean();
1097                 return $val;
1098         }
1099
1100         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1101                 if ($xlen > 1)
1102                         $xbeg .= "," . ($xbeg + $xlen - 1);
1103                 if ($ylen > 1)
1104                         $ybeg .= "," . ($ybeg + $ylen - 1);
1105
1106                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1107         }
1108
1109         function _start_block($header) {
1110                 echo $header;
1111         }
1112
1113         function _end_block() {
1114         }
1115
1116         function _lines($lines, $prefix = ' ') {
1117                 foreach ($lines as $line)
1118                         echo "$prefix $line\n";
1119         }
1120
1121         function _context($lines) {
1122                 $this->_lines($lines);
1123         }
1124
1125         function _added($lines) {
1126                 $this->_lines($lines, '>');
1127         }
1128         function _deleted($lines) {
1129                 $this->_lines($lines, '<');
1130         }
1131
1132         function _changed($orig, $closing) {
1133                 $this->_deleted($orig);
1134                 echo "---\n";
1135                 $this->_added($closing);
1136         }
1137 }
1138
1139
1140 /**
1141  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
1142  *
1143  */
1144
1145 define('NBSP', '&#160;');                       // iso-8859-x non-breaking space.
1146
1147 class _HWLDF_WordAccumulator {
1148         function _HWLDF_WordAccumulator () {
1149                 $this->_lines = array();
1150                 $this->_line = '';
1151                 $this->_group = '';
1152                 $this->_tag = '';
1153         }
1154
1155         function _flushGroup ($new_tag) {
1156                 if ($this->_group !== '') {
1157                         if ($this->_tag == 'mark')
1158                                 $this->_line .= '<span class="diffchange">'.htmlspecialchars ( $this->_group ).'</span>';
1159                         else
1160                                 $this->_line .= htmlspecialchars ( $this->_group );
1161                 }
1162                 $this->_group = '';
1163                 $this->_tag = $new_tag;
1164         }
1165
1166         function _flushLine ($new_tag) {
1167                 $this->_flushGroup($new_tag);
1168                 if ($this->_line != '')
1169                         array_push ( $this->_lines, $this->_line );
1170                 else
1171                         array_push ( $this->_lines, NBSP );
1172                 $this->_line = '';
1173         }
1174
1175         function addWords ($words, $tag = '') {
1176                 if ($tag != $this->_tag)
1177                         $this->_flushGroup($tag);
1178
1179                 foreach ($words as $word) {
1180                         // new-line should only come as first char of word.
1181                         if ($word == '')
1182                                 continue;
1183                         if ($word[0] == "\n") {
1184                                 $this->_flushLine($tag);
1185                                 $word = substr($word, 1);
1186                         }
1187                         assert(!strstr($word, "\n"));
1188                         $this->_group .= $word;
1189                 }
1190         }
1191
1192         function getLines() {
1193                 $this->_flushLine('~done');
1194                 return $this->_lines;
1195         }
1196 }
1197
1198 class WordLevelDiff extends MappedDiff
1199 {
1200         function WordLevelDiff ($orig_lines, $closing_lines) {
1201                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
1202                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
1203
1204
1205                 $this->MappedDiff($orig_words, $closing_words,
1206                                                   $orig_stripped, $closing_stripped);
1207         }
1208
1209         function _split($lines) {
1210                 if (!preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
1211                                                         implode("\n", $lines),
1212                                                         $m)) {
1213                         return array(array(''), array(''));
1214                 }
1215                 return array($m[0], $m[1]);
1216         }
1217
1218         function orig () {
1219                 $orig = new _HWLDF_WordAccumulator;
1220
1221                 foreach ($this->edits as $edit) {
1222                         if ($edit->type == 'copy')
1223                                 $orig->addWords($edit->orig);
1224                         elseif ($edit->orig)
1225                                 $orig->addWords($edit->orig, 'mark');
1226                 }
1227                 return $orig->getLines();
1228         }
1229
1230         function closing () {
1231                 $closing = new _HWLDF_WordAccumulator;
1232
1233                 foreach ($this->edits as $edit) {
1234                         if ($edit->type == 'copy')
1235                                 $closing->addWords($edit->closing);
1236                         elseif ($edit->closing)
1237                                 $closing->addWords($edit->closing, 'mark');
1238                 }
1239                 return $closing->getLines();
1240         }
1241 }
1242
1243 /**
1244  *      Wikipedia Table style diff formatter.
1245  *
1246  */
1247 class TableDiffFormatter extends DiffFormatter
1248 {
1249         function TableDiffFormatter() {
1250                 $this->leading_context_lines = 2;
1251                 $this->trailing_context_lines = 2;
1252         }
1253
1254         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
1255                 $l1 = wfMsg( 'lineno', $xbeg );
1256                 $l2 = wfMsg( 'lineno', $ybeg );
1257
1258                 $r = '<tr><td colspan="2" align="left"><strong>'.$l1."</strong></td>\n" .
1259                         '<td colspan="2" align="left"><strong>'.$l2."</strong></td></tr>\n";
1260                 return $r;
1261         }
1262
1263         function _start_block( $header ) {
1264                 global $wgOut;
1265                 $wgOut->addHTML( $header );
1266         }
1267
1268         function _end_block() {
1269         }
1270
1271         function _lines( $lines, $prefix=' ', $color='white' ) {
1272         }
1273
1274         function addedLine( $line ) {
1275                 return '<td>+</td><td class="diff-addedline">' .
1276                         $line . '</td>';
1277         }
1278
1279         function deletedLine( $line ) {
1280                 return '<td>-</td><td class="diff-deletedline">' .
1281                         $line . '</td>';
1282         }
1283
1284         function emptyLine() {
1285                 return '<td colspan="2">&nbsp;</td>';
1286         }
1287
1288         function contextLine( $line ) {
1289                 return '<td> </td><td class="diff-context">' .
1290                         htmlspecialchars ( $line ) . '</td>';
1291         }
1292
1293         function _added($lines) {
1294                 global $wgOut;
1295                 foreach ($lines as $line) {
1296                         $wgOut->addHTML( '<tr>' . $this->emptyLine() .
1297                           $this->addedLine( htmlspecialchars ( $line ) ) . "</tr>\n" );
1298                 }
1299         }
1300
1301         function _deleted($lines) {
1302                 global $wgOut;
1303                 foreach ($lines as $line) {
1304                         $wgOut->addHTML( '<tr>' . $this->deletedLine( htmlspecialchars ( $line ) ) .
1305                           $this->emptyLine() . "</tr>\n" );
1306                 }
1307         }
1308
1309         function _context( $lines ) {
1310                 global $wgOut;
1311                 foreach ($lines as $line) {
1312                         $wgOut->addHTML( '<tr>' . $this->contextLine( $line ) .
1313                           $this->contextLine( $line ) . "</tr>\n" );
1314                 }
1315         }
1316
1317         function _changed( $orig, $closing ) {
1318                 global $wgOut;
1319                 $diff = new WordLevelDiff( $orig, $closing );
1320                 $del = $diff->orig();
1321                 $add = $diff->closing();
1322
1323                 while ( $line = array_shift( $del ) ) {
1324                         $aline = array_shift( $add );
1325                         $wgOut->addHTML( '<tr>' . $this->deletedLine( $line ) .
1326                           $this->addedLine( $aline ) . "</tr>\n" );
1327                 }
1328                 $this->_added( $add ); # If any leftovers
1329         }
1330 }
1331
1332 ?>