+<?php
+/**
+ * A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
+ *
+ * Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
+ * You may copy this code freely under the conditions of the GPL.
+ *
+ * @file
+ * @ingroup DifferenceEngine
+ * @defgroup DifferenceEngine DifferenceEngine
+ */
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _DiffOp {
+ var $type;
+ var $orig;
+ var $closing;
+
+ function reverse() {
+ trigger_error('pure virtual', E_USER_ERROR);
+ }
+
+ function norig() {
+ return $this->orig ? sizeof($this->orig) : 0;
+ }
+
+ function nclosing() {
+ return $this->closing ? sizeof($this->closing) : 0;
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _DiffOp_Copy extends _DiffOp {
+ var $type = 'copy';
+
+ function __construct ($orig, $closing = false) {
+ if (!is_array($closing))
+ $closing = $orig;
+ $this->orig = $orig;
+ $this->closing = $closing;
+ }
+
+ function reverse() {
+ return new _DiffOp_Copy($this->closing, $this->orig);
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _DiffOp_Delete extends _DiffOp {
+ var $type = 'delete';
+
+ function __construct ($lines) {
+ $this->orig = $lines;
+ $this->closing = false;
+ }
+
+ function reverse() {
+ return new _DiffOp_Add($this->orig);
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _DiffOp_Add extends _DiffOp {
+ var $type = 'add';
+
+ function __construct ($lines) {
+ $this->closing = $lines;
+ $this->orig = false;
+ }
+
+ function reverse() {
+ return new _DiffOp_Delete($this->closing);
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _DiffOp_Change extends _DiffOp {
+ var $type = 'change';
+
+ function __construct ($orig, $closing) {
+ $this->orig = $orig;
+ $this->closing = $closing;
+ }
+
+ function reverse() {
+ return new _DiffOp_Change($this->closing, $this->orig);
+ }
+}
+
+/**
+ * Class used internally by Diff to actually compute the diffs.
+ *
+ * The algorithm used here is mostly lifted from the perl module
+ * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
+ * http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
+ *
+ * More ideas are taken from:
+ * http://www.ics.uci.edu/~eppstein/161/960229.html
+ *
+ * Some ideas are (and a bit of code) are from from analyze.c, from GNU
+ * diffutils-2.7, which can be found at:
+ * ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
+ *
+ * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
+ * are my own.
+ *
+ * Line length limits for robustness added by Tim Starling, 2005-08-31
+ * Alternative implementation added by Guy Van den Broeck, 2008-07-30
+ *
+ * @author Geoffrey T. Dairiki, Tim Starling, Guy Van den Broeck
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _DiffEngine {
+
+ const MAX_XREF_LENGTH = 10000;
+
+ function diff ($from_lines, $to_lines){
+ wfProfileIn( __METHOD__ );
+
+ // Diff and store locally
+ $this->diff_local($from_lines, $to_lines);
+
+ // Merge edits when possible
+ $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
+ $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
+
+ // Compute the edit operations.
+ $n_from = sizeof($from_lines);
+ $n_to = sizeof($to_lines);
+
+ $edits = array();
+ $xi = $yi = 0;
+ while ($xi < $n_from || $yi < $n_to) {
+ assert($yi < $n_to || $this->xchanged[$xi]);
+ assert($xi < $n_from || $this->ychanged[$yi]);
+
+ // Skip matching "snake".
+ $copy = array();
+ while ( $xi < $n_from && $yi < $n_to
+ && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
+ $copy[] = $from_lines[$xi++];
+ ++$yi;
+ }
+ if ($copy)
+ $edits[] = new _DiffOp_Copy($copy);
+
+ // Find deletes & adds.
+ $delete = array();
+ while ($xi < $n_from && $this->xchanged[$xi])
+ $delete[] = $from_lines[$xi++];
+
+ $add = array();
+ while ($yi < $n_to && $this->ychanged[$yi])
+ $add[] = $to_lines[$yi++];
+
+ if ($delete && $add)
+ $edits[] = new _DiffOp_Change($delete, $add);
+ elseif ($delete)
+ $edits[] = new _DiffOp_Delete($delete);
+ elseif ($add)
+ $edits[] = new _DiffOp_Add($add);
+ }
+ wfProfileOut( __METHOD__ );
+ return $edits;
+ }
+
+ function diff_local ($from_lines, $to_lines) {
+ global $wgExternalDiffEngine;
+ wfProfileIn( __METHOD__);
+
+ if($wgExternalDiffEngine == 'wikidiff3'){
+ // wikidiff3
+ $wikidiff3 = new WikiDiff3();
+ $wikidiff3->diff($from_lines, $to_lines);
+ $this->xchanged = $wikidiff3->removed;
+ $this->ychanged = $wikidiff3->added;
+ unset($wikidiff3);
+ }else{
+ // old diff
+ $n_from = sizeof($from_lines);
+ $n_to = sizeof($to_lines);
+ $this->xchanged = $this->ychanged = array();
+ $this->xv = $this->yv = array();
+ $this->xind = $this->yind = array();
+ unset($this->seq);
+ unset($this->in_seq);
+ unset($this->lcs);
+
+ // Skip leading common lines.
+ for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
+ if ($from_lines[$skip] !== $to_lines[$skip])
+ break;
+ $this->xchanged[$skip] = $this->ychanged[$skip] = false;
+ }
+ // Skip trailing common lines.
+ $xi = $n_from; $yi = $n_to;
+ for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
+ if ($from_lines[$xi] !== $to_lines[$yi])
+ break;
+ $this->xchanged[$xi] = $this->ychanged[$yi] = false;
+ }
+
+ // Ignore lines which do not exist in both files.
+ for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
+ $xhash[$this->_line_hash($from_lines[$xi])] = 1;
+ }
+
+ for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
+ $line = $to_lines[$yi];
+ if ( ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) )
+ continue;
+ $yhash[$this->_line_hash($line)] = 1;
+ $this->yv[] = $line;
+ $this->yind[] = $yi;
+ }
+ for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
+ $line = $from_lines[$xi];
+ if ( ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) )
+ continue;
+ $this->xv[] = $line;
+ $this->xind[] = $xi;
+ }
+
+ // Find the LCS.
+ $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
+ }
+ wfProfileOut( __METHOD__ );
+ }
+
+ /**
+ * Returns the whole line if it's small enough, or the MD5 hash otherwise
+ */
+ function _line_hash( $line ) {
+ if ( strlen( $line ) > self::MAX_XREF_LENGTH ) {
+ return md5( $line );
+ } else {
+ return $line;
+ }
+ }
+
+ /* Divide the Largest Common Subsequence (LCS) of the sequences
+ * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
+ * sized segments.
+ *
+ * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an
+ * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
+ * sub sequences. The first sub-sequence is contained in [X0, X1),
+ * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on. Note
+ * that (X0, Y0) == (XOFF, YOFF) and
+ * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
+ *
+ * This function assumes that the first lines of the specified portions
+ * of the two files do not match, and likewise that the last lines do not
+ * match. The caller must trim matching lines from the beginning and end
+ * of the portions it is going to specify.
+ */
+ function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
+ $flip = false;
+
+ if ($xlim - $xoff > $ylim - $yoff) {
+ // Things seems faster (I'm not sure I understand why)
+ // when the shortest sequence in X.
+ $flip = true;
+ list ($xoff, $xlim, $yoff, $ylim)
+ = array( $yoff, $ylim, $xoff, $xlim);
+ }
+
+ if ($flip)
+ for ($i = $ylim - 1; $i >= $yoff; $i--)
+ $ymatches[$this->xv[$i]][] = $i;
+ else
+ for ($i = $ylim - 1; $i >= $yoff; $i--)
+ $ymatches[$this->yv[$i]][] = $i;
+
+ $this->lcs = 0;
+ $this->seq[0]= $yoff - 1;
+ $this->in_seq = array();
+ $ymids[0] = array();
+
+ $numer = $xlim - $xoff + $nchunks - 1;
+ $x = $xoff;
+ for ($chunk = 0; $chunk < $nchunks; $chunk++) {
+ if ($chunk > 0)
+ for ($i = 0; $i <= $this->lcs; $i++)
+ $ymids[$i][$chunk-1] = $this->seq[$i];
+
+ $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
+ for ( ; $x < $x1; $x++) {
+ $line = $flip ? $this->yv[$x] : $this->xv[$x];
+ if (empty($ymatches[$line])) {
+ continue;
+ }
+ $matches = $ymatches[$line];
+ reset($matches);
+ while ( list( $junk, $y ) = each( $matches ) ) {
+ if ( empty( $this->in_seq[$y] ) ) {
+ $k = $this->_lcs_pos( $y );
+ assert( $k > 0 );
+ $ymids[$k] = $ymids[$k-1];
+ break;
+ }
+ }
+ while (list ( /* $junk */, $y) = each($matches)) {
+ if ($y > $this->seq[$k-1]) {
+ assert($y < $this->seq[$k]);
+ // Optimization: this is a common case:
+ // next match is just replacing previous match.
+ $this->in_seq[$this->seq[$k]] = false;
+ $this->seq[$k] = $y;
+ $this->in_seq[$y] = 1;
+ } else if (empty($this->in_seq[$y])) {
+ $k = $this->_lcs_pos($y);
+ assert($k > 0);
+ $ymids[$k] = $ymids[$k-1];
+ }
+ }
+ }
+ }
+
+ $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
+ $ymid = $ymids[$this->lcs];
+ for ($n = 0; $n < $nchunks - 1; $n++) {
+ $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
+ $y1 = $ymid[$n] + 1;
+ $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
+ }
+ $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
+
+ return array($this->lcs, $seps);
+ }
+
+ function _lcs_pos ($ypos) {
+ $end = $this->lcs;
+ if ($end == 0 || $ypos > $this->seq[$end]) {
+ $this->seq[++$this->lcs] = $ypos;
+ $this->in_seq[$ypos] = 1;
+ return $this->lcs;
+ }
+
+ $beg = 1;
+ while ($beg < $end) {
+ $mid = (int)(($beg + $end) / 2);
+ if ( $ypos > $this->seq[$mid] )
+ $beg = $mid + 1;
+ else
+ $end = $mid;
+ }
+
+ assert($ypos != $this->seq[$end]);
+
+ $this->in_seq[$this->seq[$end]] = false;
+ $this->seq[$end] = $ypos;
+ $this->in_seq[$ypos] = 1;
+ return $end;
+ }
+
+ /* Find LCS of two sequences.
+ *
+ * The results are recorded in the vectors $this->{x,y}changed[], by
+ * storing a 1 in the element for each line that is an insertion
+ * or deletion (ie. is not in the LCS).
+ *
+ * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
+ *
+ * Note that XLIM, YLIM are exclusive bounds.
+ * All line numbers are origin-0 and discarded lines are not counted.
+ */
+ function _compareseq ($xoff, $xlim, $yoff, $ylim) {
+ // Slide down the bottom initial diagonal.
+ while ($xoff < $xlim && $yoff < $ylim
+ && $this->xv[$xoff] == $this->yv[$yoff]) {
+ ++$xoff;
+ ++$yoff;
+ }
+
+ // Slide up the top initial diagonal.
+ while ($xlim > $xoff && $ylim > $yoff
+ && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
+ --$xlim;
+ --$ylim;
+ }
+
+ if ($xoff == $xlim || $yoff == $ylim)
+ $lcs = 0;
+ else {
+ // This is ad hoc but seems to work well.
+ //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
+ //$nchunks = max(2,min(8,(int)$nchunks));
+ $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
+ list ($lcs, $seps)
+ = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
+ }
+
+ if ($lcs == 0) {
+ // X and Y sequences have no common subsequence:
+ // mark all changed.
+ while ($yoff < $ylim)
+ $this->ychanged[$this->yind[$yoff++]] = 1;
+ while ($xoff < $xlim)
+ $this->xchanged[$this->xind[$xoff++]] = 1;
+ } else {
+ // Use the partitions to split this problem into subproblems.
+ reset($seps);
+ $pt1 = $seps[0];
+ while ($pt2 = next($seps)) {
+ $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
+ $pt1 = $pt2;
+ }
+ }
+ }
+
+ /* Adjust inserts/deletes of identical lines to join changes
+ * as much as possible.
+ *
+ * We do something when a run of changed lines include a
+ * line at one end and has an excluded, identical line at the other.
+ * We are free to choose which identical line is included.
+ * `compareseq' usually chooses the one at the beginning,
+ * but usually it is cleaner to consider the following identical line
+ * to be the "change".
+ *
+ * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
+ */
+ function _shift_boundaries ($lines, &$changed, $other_changed) {
+ wfProfileIn( __METHOD__ );
+ $i = 0;
+ $j = 0;
+
+ assert('sizeof($lines) == sizeof($changed)');
+ $len = sizeof($lines);
+ $other_len = sizeof($other_changed);
+
+ while (1) {
+ /*
+ * Scan forwards to find beginning of another run of changes.
+ * Also keep track of the corresponding point in the other file.
+ *
+ * Throughout this code, $i and $j are adjusted together so that
+ * the first $i elements of $changed and the first $j elements
+ * of $other_changed both contain the same number of zeros
+ * (unchanged lines).
+ * Furthermore, $j is always kept so that $j == $other_len or
+ * $other_changed[$j] == false.
+ */
+ while ($j < $other_len && $other_changed[$j])
+ $j++;
+
+ while ($i < $len && ! $changed[$i]) {
+ assert('$j < $other_len && ! $other_changed[$j]');
+ $i++; $j++;
+ while ($j < $other_len && $other_changed[$j])
+ $j++;
+ }
+
+ if ($i == $len)
+ break;
+
+ $start = $i;
+
+ // Find the end of this run of changes.
+ while (++$i < $len && $changed[$i])
+ continue;
+
+ do {
+ /*
+ * Record the length of this run of changes, so that
+ * we can later determine whether the run has grown.
+ */
+ $runlength = $i - $start;
+
+ /*
+ * Move the changed region back, so long as the
+ * previous unchanged line matches the last changed one.
+ * This merges with previous changed regions.
+ */
+ while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
+ $changed[--$start] = 1;
+ $changed[--$i] = false;
+ while ($start > 0 && $changed[$start - 1])
+ $start--;
+ assert('$j > 0');
+ while ($other_changed[--$j])
+ continue;
+ assert('$j >= 0 && !$other_changed[$j]');
+ }
+
+ /*
+ * Set CORRESPONDING to the end of the changed run, at the last
+ * point where it corresponds to a changed run in the other file.
+ * CORRESPONDING == LEN means no such point has been found.
+ */
+ $corresponding = $j < $other_len ? $i : $len;
+
+ /*
+ * Move the changed region forward, so long as the
+ * first changed line matches the following unchanged one.
+ * This merges with following changed regions.
+ * Do this second, so that if there are no merges,
+ * the changed region is moved forward as far as possible.
+ */
+ while ($i < $len && $lines[$start] == $lines[$i]) {
+ $changed[$start++] = false;
+ $changed[$i++] = 1;
+ while ($i < $len && $changed[$i])
+ $i++;
+
+ assert('$j < $other_len && ! $other_changed[$j]');
+ $j++;
+ if ($j < $other_len && $other_changed[$j]) {
+ $corresponding = $i;
+ while ($j < $other_len && $other_changed[$j])
+ $j++;
+ }
+ }
+ } while ($runlength != $i - $start);
+
+ /*
+ * If possible, move the fully-merged run of changes
+ * back to a corresponding run in the other file.
+ */
+ while ($corresponding < $i) {
+ $changed[--$start] = 1;
+ $changed[--$i] = 0;
+ assert('$j > 0');
+ while ($other_changed[--$j])
+ continue;
+ assert('$j >= 0 && !$other_changed[$j]');
+ }
+ }
+ wfProfileOut( __METHOD__ );
+ }
+}
+
+/**
+ * Class representing a 'diff' between two sequences of strings.
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class Diff
+{
+ var $edits;
+
+ /**
+ * Constructor.
+ * Computes diff between sequences of strings.
+ *
+ * @param $from_lines array An array of strings.
+ * (Typically these are lines from a file.)
+ * @param $to_lines array An array of strings.
+ */
+ function __construct($from_lines, $to_lines) {
+ $eng = new _DiffEngine;
+ $this->edits = $eng->diff($from_lines, $to_lines);
+ //$this->_check($from_lines, $to_lines);
+ }
+
+ /**
+ * Compute reversed Diff.
+ *
+ * SYNOPSIS:
+ *
+ * $diff = new Diff($lines1, $lines2);
+ * $rev = $diff->reverse();
+ * @return object A Diff object representing the inverse of the
+ * original diff.
+ */
+ function reverse () {
+ $rev = $this;
+ $rev->edits = array();
+ foreach ($this->edits as $edit) {
+ $rev->edits[] = $edit->reverse();
+ }
+ return $rev;
+ }
+
+ /**
+ * Check for empty diff.
+ *
+ * @return bool True iff two sequences were identical.
+ */
+ function isEmpty () {
+ foreach ($this->edits as $edit) {
+ if ($edit->type != 'copy')
+ return false;
+ }
+ return true;
+ }
+
+ /**
+ * Compute the length of the Longest Common Subsequence (LCS).
+ *
+ * This is mostly for diagnostic purposed.
+ *
+ * @return int The length of the LCS.
+ */
+ function lcs () {
+ $lcs = 0;
+ foreach ($this->edits as $edit) {
+ if ($edit->type == 'copy')
+ $lcs += sizeof($edit->orig);
+ }
+ return $lcs;
+ }
+
+ /**
+ * Get the original set of lines.
+ *
+ * This reconstructs the $from_lines parameter passed to the
+ * constructor.
+ *
+ * @return array The original sequence of strings.
+ */
+ function orig() {
+ $lines = array();
+
+ foreach ($this->edits as $edit) {
+ if ($edit->orig)
+ array_splice($lines, sizeof($lines), 0, $edit->orig);
+ }
+ return $lines;
+ }
+
+ /**
+ * Get the closing set of lines.
+ *
+ * This reconstructs the $to_lines parameter passed to the
+ * constructor.
+ *
+ * @return array The sequence of strings.
+ */
+ function closing() {
+ $lines = array();
+
+ foreach ($this->edits as $edit) {
+ if ($edit->closing)
+ array_splice($lines, sizeof($lines), 0, $edit->closing);
+ }
+ return $lines;
+ }
+
+ /**
+ * Check a Diff for validity.
+ *
+ * This is here only for debugging purposes.
+ */
+ function _check ($from_lines, $to_lines) {
+ wfProfileIn( __METHOD__ );
+ if (serialize($from_lines) != serialize($this->orig()))
+ trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
+ if (serialize($to_lines) != serialize($this->closing()))
+ trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
+
+ $rev = $this->reverse();
+ if (serialize($to_lines) != serialize($rev->orig()))
+ trigger_error("Reversed original doesn't match", E_USER_ERROR);
+ if (serialize($from_lines) != serialize($rev->closing()))
+ trigger_error("Reversed closing doesn't match", E_USER_ERROR);
+
+
+ $prevtype = 'none';
+ foreach ($this->edits as $edit) {
+ if ( $prevtype == $edit->type )
+ trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
+ $prevtype = $edit->type;
+ }
+
+ $lcs = $this->lcs();
+ trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
+ wfProfileOut( __METHOD__ );
+ }
+}
+
+/**
+ * @todo document, bad name.
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class MappedDiff extends Diff
+{
+ /**
+ * Constructor.
+ *
+ * Computes diff between sequences of strings.
+ *
+ * This can be used to compute things like
+ * case-insensitve diffs, or diffs which ignore
+ * changes in white-space.
+ *
+ * @param $from_lines array An array of strings.
+ * (Typically these are lines from a file.)
+ *
+ * @param $to_lines array An array of strings.
+ *
+ * @param $mapped_from_lines array This array should
+ * have the same size number of elements as $from_lines.
+ * The elements in $mapped_from_lines and
+ * $mapped_to_lines are what is actually compared
+ * when computing the diff.
+ *
+ * @param $mapped_to_lines array This array should
+ * have the same number of elements as $to_lines.
+ */
+ function __construct($from_lines, $to_lines,
+ $mapped_from_lines, $mapped_to_lines) {
+ wfProfileIn( __METHOD__ );
+
+ assert(sizeof($from_lines) == sizeof($mapped_from_lines));
+ assert(sizeof($to_lines) == sizeof($mapped_to_lines));
+
+ parent::__construct($mapped_from_lines, $mapped_to_lines);
+
+ $xi = $yi = 0;
+ for ($i = 0; $i < sizeof($this->edits); $i++) {
+ $orig = &$this->edits[$i]->orig;
+ if (is_array($orig)) {
+ $orig = array_slice($from_lines, $xi, sizeof($orig));
+ $xi += sizeof($orig);
+ }
+
+ $closing = &$this->edits[$i]->closing;
+ if (is_array($closing)) {
+ $closing = array_slice($to_lines, $yi, sizeof($closing));
+ $yi += sizeof($closing);
+ }
+ }
+ wfProfileOut( __METHOD__ );
+ }
+}
+
+/**
+ * A class to format Diffs
+ *
+ * This class formats the diff in classic diff format.
+ * It is intended that this class be customized via inheritance,
+ * to obtain fancier outputs.
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class DiffFormatter {
+ /**
+ * Number of leading context "lines" to preserve.
+ *
+ * This should be left at zero for this class, but subclasses
+ * may want to set this to other values.
+ */
+ var $leading_context_lines = 0;
+
+ /**
+ * Number of trailing context "lines" to preserve.
+ *
+ * This should be left at zero for this class, but subclasses
+ * may want to set this to other values.
+ */
+ var $trailing_context_lines = 0;
+
+ /**
+ * Format a diff.
+ *
+ * @param $diff object A Diff object.
+ * @return string The formatted output.
+ */
+ function format($diff) {
+ wfProfileIn( __METHOD__ );
+
+ $xi = $yi = 1;
+ $block = false;
+ $context = array();
+
+ $nlead = $this->leading_context_lines;
+ $ntrail = $this->trailing_context_lines;
+
+ $this->_start_diff();
+
+ foreach ($diff->edits as $edit) {
+ if ($edit->type == 'copy') {
+ if (is_array($block)) {
+ if (sizeof($edit->orig) <= $nlead + $ntrail) {
+ $block[] = $edit;
+ }
+ else{
+ if ($ntrail) {
+ $context = array_slice($edit->orig, 0, $ntrail);
+ $block[] = new _DiffOp_Copy($context);
+ }
+ $this->_block($x0, $ntrail + $xi - $x0,
+ $y0, $ntrail + $yi - $y0,
+ $block);
+ $block = false;
+ }
+ }
+ $context = $edit->orig;
+ }
+ else {
+ if (! is_array($block)) {
+ $context = array_slice($context, sizeof($context) - $nlead);
+ $x0 = $xi - sizeof($context);
+ $y0 = $yi - sizeof($context);
+ $block = array();
+ if ($context)
+ $block[] = new _DiffOp_Copy($context);
+ }
+ $block[] = $edit;
+ }
+
+ if ($edit->orig)
+ $xi += sizeof($edit->orig);
+ if ($edit->closing)
+ $yi += sizeof($edit->closing);
+ }
+
+ if (is_array($block))
+ $this->_block($x0, $xi - $x0,
+ $y0, $yi - $y0,
+ $block);
+
+ $end = $this->_end_diff();
+ wfProfileOut( __METHOD__ );
+ return $end;
+ }
+
+ function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
+ wfProfileIn( __METHOD__ );
+ $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
+ foreach ($edits as $edit) {
+ if ($edit->type == 'copy')
+ $this->_context($edit->orig);
+ elseif ($edit->type == 'add')
+ $this->_added($edit->closing);
+ elseif ($edit->type == 'delete')
+ $this->_deleted($edit->orig);
+ elseif ($edit->type == 'change')
+ $this->_changed($edit->orig, $edit->closing);
+ else
+ trigger_error('Unknown edit type', E_USER_ERROR);
+ }
+ $this->_end_block();
+ wfProfileOut( __METHOD__ );
+ }
+
+ function _start_diff() {
+ ob_start();
+ }
+
+ function _end_diff() {
+ $val = ob_get_contents();
+ ob_end_clean();
+ return $val;
+ }
+
+ function _block_header($xbeg, $xlen, $ybeg, $ylen) {
+ if ($xlen > 1)
+ $xbeg .= "," . ($xbeg + $xlen - 1);
+ if ($ylen > 1)
+ $ybeg .= "," . ($ybeg + $ylen - 1);
+
+ return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
+ }
+
+ function _start_block($header) {
+ echo $header . "\n";
+ }
+
+ function _end_block() {
+ }
+
+ function _lines($lines, $prefix = ' ') {
+ foreach ($lines as $line)
+ echo "$prefix $line\n";
+ }
+
+ function _context($lines) {
+ $this->_lines($lines);
+ }
+
+ function _added($lines) {
+ $this->_lines($lines, '>');
+ }
+ function _deleted($lines) {
+ $this->_lines($lines, '<');
+ }
+
+ function _changed($orig, $closing) {
+ $this->_deleted($orig);
+ echo "---\n";
+ $this->_added($closing);
+ }
+}
+
+/**
+ * A formatter that outputs unified diffs
+ * @ingroup DifferenceEngine
+ */
+
+class UnifiedDiffFormatter extends DiffFormatter {
+ var $leading_context_lines = 2;
+ var $trailing_context_lines = 2;
+
+ function _added($lines) {
+ $this->_lines($lines, '+');
+ }
+ function _deleted($lines) {
+ $this->_lines($lines, '-');
+ }
+ function _changed($orig, $closing) {
+ $this->_deleted($orig);
+ $this->_added($closing);
+ }
+ function _block_header($xbeg, $xlen, $ybeg, $ylen) {
+ return "@@ -$xbeg,$xlen +$ybeg,$ylen @@";
+ }
+}
+
+/**
+ * A pseudo-formatter that just passes along the Diff::$edits array
+ * @ingroup DifferenceEngine
+ */
+class ArrayDiffFormatter extends DiffFormatter {
+ function format($diff) {
+ $oldline = 1;
+ $newline = 1;
+ $retval = array();
+ foreach($diff->edits as $edit)
+ switch($edit->type) {
+ case 'add':
+ foreach($edit->closing as $l) {
+ $retval[] = array(
+ 'action' => 'add',
+ 'new'=> $l,
+ 'newline' => $newline++
+ );
+ }
+ break;
+ case 'delete':
+ foreach($edit->orig as $l) {
+ $retval[] = array(
+ 'action' => 'delete',
+ 'old' => $l,
+ 'oldline' => $oldline++,
+ );
+ }
+ break;
+ case 'change':
+ foreach($edit->orig as $i => $l) {
+ $retval[] = array(
+ 'action' => 'change',
+ 'old' => $l,
+ 'new' => @$edit->closing[$i],
+ 'oldline' => $oldline++,
+ 'newline' => $newline++,
+ );
+ }
+ break;
+ case 'copy':
+ $oldline += count($edit->orig);
+ $newline += count($edit->orig);
+ }
+ return $retval;
+ }
+}
+
+/**
+ * Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
+ *
+ */
+
+define('NBSP', ' '); // iso-8859-x non-breaking space.
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class _HWLDF_WordAccumulator {
+ function __construct () {
+ $this->_lines = array();
+ $this->_line = '';
+ $this->_group = '';
+ $this->_tag = '';
+ }
+
+ function _flushGroup ($new_tag) {
+ if ($this->_group !== '') {
+ if ($this->_tag == 'ins')
+ $this->_line .= '<ins class="diffchange diffchange-inline">' .
+ htmlspecialchars ( $this->_group ) . '</ins>';
+ elseif ($this->_tag == 'del')
+ $this->_line .= '<del class="diffchange diffchange-inline">' .
+ htmlspecialchars ( $this->_group ) . '</del>';
+ else
+ $this->_line .= htmlspecialchars ( $this->_group );
+ }
+ $this->_group = '';
+ $this->_tag = $new_tag;
+ }
+
+ function _flushLine ($new_tag) {
+ $this->_flushGroup($new_tag);
+ if ($this->_line != '')
+ array_push ( $this->_lines, $this->_line );
+ else
+ # make empty lines visible by inserting an NBSP
+ array_push ( $this->_lines, NBSP );
+ $this->_line = '';
+ }
+
+ function addWords ($words, $tag = '') {
+ if ($tag != $this->_tag)
+ $this->_flushGroup($tag);
+
+ foreach ($words as $word) {
+ // new-line should only come as first char of word.
+ if ($word == '')
+ continue;
+ if ($word[0] == "\n") {
+ $this->_flushLine($tag);
+ $word = substr($word, 1);
+ }
+ assert(!strstr($word, "\n"));
+ $this->_group .= $word;
+ }
+ }
+
+ function getLines() {
+ $this->_flushLine('~done');
+ return preg_replace( '/\n/m', '', $this->_lines);
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class WordLevelDiff extends MappedDiff {
+ const MAX_LINE_LENGTH = 10000;
+
+ function __construct ($orig_lines, $closing_lines) {
+ wfProfileIn( __METHOD__ );
+
+ list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
+ list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
+
+ parent::__construct($orig_words, $closing_words,
+ $orig_stripped, $closing_stripped);
+ wfProfileOut( __METHOD__ );
+ }
+
+ function _split($lines) {
+ wfProfileIn( __METHOD__ );
+
+ $words = array();
+ $stripped = array();
+ $first = true;
+ foreach ( $lines as $line ) {
+ # If the line is too long, just pretend the entire line is one big word
+ # This prevents resource exhaustion problems
+ if ( $first ) {
+ $first = false;
+ } else {
+ $words[] = "\n";
+ $stripped[] = "\n";
+ }
+ if ( strlen( $line ) > self::MAX_LINE_LENGTH ) {
+ $words[] = $line;
+ $stripped[] = $line;
+ } else {
+ $m = array();
+ if (preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
+ $line, $m))
+ {
+ $words = array_merge( $words, $m[0] );
+ $stripped = array_merge( $stripped, $m[1] );
+ }
+ }
+ }
+ wfProfileOut( __METHOD__ );
+ return array($words, $stripped);
+ }
+
+ function orig () {
+ wfProfileIn( __METHOD__ );
+ $orig = new _HWLDF_WordAccumulator;
+
+ foreach ($this->edits as $edit) {
+ if ($edit->type == 'copy')
+ $orig->addWords($edit->orig);
+ elseif ($edit->orig)
+ $orig->addWords($edit->orig, 'del');
+ }
+ $lines = $orig->getLines();
+ wfProfileOut( __METHOD__ );
+ return $lines;
+ }
+
+ function closing () {
+ wfProfileIn( __METHOD__ );
+ $closing = new _HWLDF_WordAccumulator;
+
+ foreach ($this->edits as $edit) {
+ if ($edit->type == 'copy')
+ $closing->addWords($edit->closing);
+ elseif ($edit->closing)
+ $closing->addWords($edit->closing, 'ins');
+ }
+ $lines = $closing->getLines();
+ wfProfileOut( __METHOD__ );
+ return $lines;
+ }
+}
+
+/**
+ * Wikipedia Table style diff formatter.
+ * @todo document
+ * @private
+ * @ingroup DifferenceEngine
+ */
+class TableDiffFormatter extends DiffFormatter {
+ function __construct() {
+ $this->leading_context_lines = 2;
+ $this->trailing_context_lines = 2;
+ }
+
+ public static function escapeWhiteSpace( $msg ) {
+ $msg = preg_replace( '/^ /m', '  ', $msg );
+ $msg = preg_replace( '/ $/m', '  ', $msg );
+ $msg = preg_replace( '/ /', '  ', $msg );
+ return $msg;
+ }
+
+ function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
+ $r = '<tr><td colspan="2" class="diff-lineno"><!--LINE '.$xbeg."--></td>\n" .
+ '<td colspan="2" class="diff-lineno"><!--LINE '.$ybeg."--></td></tr>\n";
+ return $r;
+ }
+
+ function _start_block( $header ) {
+ echo $header;
+ }
+
+ function _end_block() {
+ }
+
+ function _lines( $lines, $prefix=' ', $color='white' ) {
+ }
+
+ # HTML-escape parameter before calling this
+ function addedLine( $line ) {
+ return $this->wrapLine( '+', 'diff-addedline', $line );
+ }
+
+ # HTML-escape parameter before calling this
+ function deletedLine( $line ) {
+ return $this->wrapLine( '−', 'diff-deletedline', $line );
+ }
+
+ # HTML-escape parameter before calling this
+ function contextLine( $line ) {
+ return $this->wrapLine( ' ', 'diff-context', $line );
+ }
+
+ private function wrapLine( $marker, $class, $line ) {
+ if( $line !== '' ) {
+ // The <div> wrapper is needed for 'overflow: auto' style to scroll properly
+ $line = Xml::tags( 'div', null, $this->escapeWhiteSpace( $line ) );
+ }
+ return "<td class='diff-marker'>$marker</td><td class='$class'>$line</td>";
+ }
+
+ function emptyLine() {
+ return '<td colspan="2"> </td>';
+ }
+
+ function _added( $lines ) {
+ foreach ($lines as $line) {
+ echo '<tr>' . $this->emptyLine() .
+ $this->addedLine( '<ins class="diffchange">' .
+ htmlspecialchars ( $line ) . '</ins>' ) . "</tr>\n";
+ }
+ }
+
+ function _deleted($lines) {
+ foreach ($lines as $line) {
+ echo '<tr>' . $this->deletedLine( '<del class="diffchange">' .
+ htmlspecialchars ( $line ) . '</del>' ) .
+ $this->emptyLine() . "</tr>\n";
+ }
+ }
+
+ function _context( $lines ) {
+ foreach ($lines as $line) {
+ echo '<tr>' .
+ $this->contextLine( htmlspecialchars ( $line ) ) .
+ $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
+ }
+ }
+
+ function _changed( $orig, $closing ) {
+ wfProfileIn( __METHOD__ );
+
+ $diff = new WordLevelDiff( $orig, $closing );
+ $del = $diff->orig();
+ $add = $diff->closing();
+
+ # Notice that WordLevelDiff returns HTML-escaped output.
+ # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
+
+ while ( $line = array_shift( $del ) ) {
+ $aline = array_shift( $add );
+ echo '<tr>' . $this->deletedLine( $line ) .
+ $this->addedLine( $aline ) . "</tr>\n";
+ }
+ foreach ($add as $line) { # If any leftovers
+ echo '<tr>' . $this->emptyLine() .
+ $this->addedLine( $line ) . "</tr>\n";
+ }
+ wfProfileOut( __METHOD__ );
+ }
+}