includes/DifferenceEngine.php

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