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authorDries2012-11-21 17:56:16 (GMT)
committerDries2012-11-21 17:56:16 (GMT)
commita231532dff185f0cc7c3bab7da1d4a88dcdbac09 (patch)
treee0a7e8e7413cc41d9db3725c64faf71cd75ce860
parentc260589355dbeb16657e438665d1c5729c009b39 (diff)
Issue #120955 by moshe weitzman, Pancho, cburschka, sym, alexpott: Integrate Diff into Core.
-rw-r--r--core/lib/Drupal/Component/Diff/DiffEngine.php1349
1 files changed, 1349 insertions, 0 deletions
diff --git a/core/lib/Drupal/Component/Diff/DiffEngine.php b/core/lib/Drupal/Component/Diff/DiffEngine.php
new file mode 100644
index 0000000..1236610
--- /dev/null
+++ b/core/lib/Drupal/Component/Diff/DiffEngine.php
@@ -0,0 +1,1349 @@
+<?php
+
+/**
+ * @file
+ * A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
+ *
+ * Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
+ * You may copy this code freely under the conditions of the GPL.
+ */
+
+define('USE_ASSERTS', FALSE);
+
+/**
+ * @todo document
+ * @private
+ * @subpackage 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
+ * @subpackage DifferenceEngine
+ */
+class _DiffOp_Copy extends _DiffOp {
+ var $type = 'copy';
+
+ function _DiffOp_Copy($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
+ * @subpackage DifferenceEngine
+ */
+class _DiffOp_Delete extends _DiffOp {
+ var $type = 'delete';
+
+ function _DiffOp_Delete($lines) {
+ $this->orig = $lines;
+ $this->closing = FALSE;
+ }
+
+ function reverse() {
+ return new _DiffOp_Add($this->orig);
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class _DiffOp_Add extends _DiffOp {
+ var $type = 'add';
+
+ function _DiffOp_Add($lines) {
+ $this->closing = $lines;
+ $this->orig = FALSE;
+ }
+
+ function reverse() {
+ return new _DiffOp_Delete($this->closing);
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class _DiffOp_Change extends _DiffOp {
+ var $type = 'change';
+
+ function _DiffOp_Change($orig, $closing) {
+ $this->orig = $orig;
+ $this->closing = $closing;
+ }
+
+ function reverse() {
+ return new _DiffOp_Change($this->closing, $this->orig);
+ }
+}
+
+
+/**
+ * Class used internally by Diff to actually compute the diffs.
+ *
+ * The algorithm used here is mostly lifted from the perl module
+ * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
+ * http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
+ *
+ * More ideas are taken from:
+ * http://www.ics.uci.edu/~eppstein/161/960229.html
+ *
+ * Some ideas are (and a bit of code) are from from analyze.c, from GNU
+ * diffutils-2.7, which can be found at:
+ * ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
+ *
+ * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
+ * are my own.
+ *
+ * Line length limits for robustness added by Tim Starling, 2005-08-31
+ *
+ * @author Geoffrey T. Dairiki, Tim Starling
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class _DiffEngine {
+ function MAX_XREF_LENGTH() {
+ return 10000;
+ }
+
+ function diff($from_lines, $to_lines) {
+
+ $n_from = sizeof($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));
+
+ // 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.
+ $edits = array();
+ $xi = $yi = 0;
+ while ($xi < $n_from || $yi < $n_to) {
+ USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
+ USE_ASSERTS && 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);
+ }
+ }
+ return $edits;
+ }
+
+ /**
+ * Returns the whole line if it's small enough, or the MD5 hash otherwise.
+ */
+ function _line_hash($line) {
+ if (drupal_strlen($line) > $this->MAX_XREF_LENGTH()) {
+ return md5($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);
+ USE_ASSERTS && assert($k > 0);
+ $ymids[$k] = $ymids[$k-1];
+ break;
+ }
+ }
+ while (list ($junk, $y) = each($matches)) {
+ if ($y > $this->seq[$k-1]) {
+ USE_ASSERTS && 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;
+ }
+ elseif (empty($this->in_seq[$y])) {
+ $k = $this->_lcs_pos($y);
+ USE_ASSERTS && 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 = $mid;
+ }
+ }
+
+ USE_ASSERTS && assert($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) {
+ $i = 0;
+ $j = 0;
+
+ USE_ASSERTS && assert('sizeof($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]) {
+ USE_ASSERTS && 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]) {
+ $start--;
+ }
+ USE_ASSERTS && assert('$j > 0');
+ while ($other_changed[--$j]) {
+ continue;
+ }
+ USE_ASSERTS && 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]) {
+ $i++;
+ }
+ USE_ASSERTS && assert('$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;
+ USE_ASSERTS && assert('$j > 0');
+ while ($other_changed[--$j]) {
+ continue;
+ }
+ USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
+ }
+ }
+ }
+}
+
+/**
+ * Class representing a 'diff' between two sequences of strings.
+ * @todo document
+ * @private
+ * @subpackage 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 $to_lines array An array of strings.
+ */
+ function Diff($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, $to_lines) {
+ if (serialize($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);
+ }
+}
+
+/**
+ * FIXME: bad name.
+ * @todo document
+ * @private
+ * @subpackage 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 $to_lines.
+ */
+ function MappedDiff($from_lines, $to_lines, $mapped_from_lines, $mapped_to_lines) {
+
+ assert(sizeof($from_lines) == sizeof($mapped_from_lines));
+ assert(sizeof($to_lines) == sizeof($mapped_to_lines));
+
+ $this->Diff($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);
+ }
+ }
+ }
+}
+
+/**
+ * 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
+ * @subpackage DifferenceEngine
+ */
+class DiffFormatter {
+ /**
+ * Should a block header be shown?
+ */
+ var $show_header = TRUE;
+
+ /**
+ * 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) {
+ $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 = $this->_end_diff();
+
+ if (!empty($xi)) {
+ $this->line_stats['counter']['x'] += $xi;
+ }
+ if (!empty($yi)) {
+ $this->line_stats['counter']['y'] += $yi;
+ }
+
+ return $end;
+ }
+
+ function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
+ $this->_start_block($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();
+ }
+
+ 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) {
+ if ($this->show_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);
+ }
+}
+
+
+/**
+ * Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
+ *
+ */
+
+define('NBSP', '&#160;'); // iso-8859-x non-breaking space.
+
+/**
+ * @todo document
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class _HWLDF_WordAccumulator {
+ function _HWLDF_WordAccumulator() {
+ $this->_lines = array();
+ $this->_line = '';
+ $this->_group = '';
+ $this->_tag = '';
+ }
+
+ function _flushGroup($new_tag) {
+ if ($this->_group !== '') {
+ if ($this->_tag == 'mark') {
+ $this->_line .= '<span class="diffchange">' . check_plain($this->_group) . '</span>';
+ }
+ else {
+ $this->_line .= check_plain($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);
+ $word = drupal_substr($word, 1);
+ }
+ assert(!strstr($word, "\n"));
+ $this->_group .= $word;
+ }
+ }
+
+ function getLines() {
+ $this->_flushLine('~done');
+ return $this->_lines;
+ }
+}
+
+/**
+ * @todo document
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class WordLevelDiff extends MappedDiff {
+ function MAX_LINE_LENGTH() {
+ return 10000;
+ }
+
+ function WordLevelDiff($orig_lines, $closing_lines) {
+ list($orig_words, $orig_stripped) = $this->_split($orig_lines);
+ list($closing_words, $closing_stripped) = $this->_split($closing_lines);
+
+ $this->MappedDiff($orig_words, $closing_words, $orig_stripped, $closing_stripped);
+ }
+
+ function _split($lines) {
+ $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 ( drupal_strlen( $line ) > $this->MAX_LINE_LENGTH() ) {
+ $words[] = $line;
+ $stripped[] = $line;
+ }
+ else {
+ 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, $m[1]);
+ }
+ }
+ }
+ return array($words, $stripped);
+ }
+
+ function orig() {
+ $orig = new _HWLDF_WordAccumulator;
+
+ foreach ($this->edits as $edit) {
+ if ($edit->type == 'copy') {
+ $orig->addWords($edit->orig);
+ }
+ elseif ($edit->orig) {
+ $orig->addWords($edit->orig, 'mark');
+ }
+ }
+ $lines = $orig->getLines();
+ return $lines;
+ }
+
+ function closing() {
+ $closing = new _HWLDF_WordAccumulator;
+
+ foreach ($this->edits as $edit) {
+ if ($edit->type == 'copy') {
+ $closing->addWords($edit->closing);
+ }
+ elseif ($edit->closing) {
+ $closing->addWords($edit->closing, 'mark');
+ }
+ }
+ $lines = $closing->getLines();
+ return $lines;
+ }
+}
+
+/**
+ * Diff formatter which uses Drupal theme functions.
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class DrupalDiffFormatter extends DiffFormatter {
+
+ var $rows;
+ var $line_stats = array(
+ 'counter' => array('x' => 0, 'y' => 0),
+ 'offset' => array('x' => 0, 'y' => 0),
+ );
+
+ function DrupalDiffFormatter() {
+ $this->leading_context_lines = variable_get('diff_context_lines_leading', 2);
+ $this->trailing_context_lines = variable_get('diff_context_lines_trailing', 2);
+ }
+
+ function _start_diff() {
+ $this->rows = array();
+ }
+
+ function _end_diff() {
+ return $this->rows;
+ }
+
+ function _block_header($xbeg, $xlen, $ybeg, $ylen) {
+ return array(
+ array(
+ 'data' => theme('diff_header_line', array('lineno' => $xbeg + $this->line_stats['offset']['x'])),
+ 'colspan' => 2,
+ ),
+ array(
+ 'data' => theme('diff_header_line', array('lineno' => $ybeg + $this->line_stats['offset']['y'])),
+ 'colspan' => 2,
+ )
+ );
+ }
+
+ function _start_block($header) {
+ if ($this->show_header) {
+ $this->rows[] = $header;
+ }
+ }
+
+ function _end_block() {
+ }
+
+ function _lines($lines, $prefix=' ', $color='white') {
+ }
+
+ /**
+ * Note: you should HTML-escape parameter before calling this.
+ */
+ function addedLine($line) {
+ return array(
+ array(
+ 'data' => '+',
+ 'class' => 'diff-marker',
+ ),
+ array(
+ 'data' => theme('diff_content_line', array('line' => $line)),
+ 'class' => 'diff-context diff-addedline',
+ )
+ );
+ }
+
+ /**
+ * Note: you should HTML-escape parameter before calling this.
+ */
+ function deletedLine($line) {
+ return array(
+ array(
+ 'data' => '-',
+ 'class' => 'diff-marker',
+ ),
+ array(
+ 'data' => theme('diff_content_line', array('line' => $line)),
+ 'class' => 'diff-context diff-deletedline',
+ )
+ );
+ }
+
+ /**
+ * Note: you should HTML-escape parameter before calling this.
+ */
+ function contextLine($line) {
+ return array(
+ '&nbsp;',
+ array(
+ 'data' => theme('diff_content_line', array('line' => $line)),
+ 'class' => 'diff-context',
+ )
+ );
+ }
+
+ function emptyLine() {
+ return array(
+ '&nbsp;',
+ theme('diff_empty_line', array('line' => '&nbsp;')),
+ );
+ }
+
+ function _added($lines) {
+ foreach ($lines as $line) {
+ $this->rows[] = array_merge($this->emptyLine(), $this->addedLine(check_plain($line)));
+ }
+ }
+
+ function _deleted($lines) {
+ foreach ($lines as $line) {
+ $this->rows[] = array_merge($this->deletedLine(check_plain($line)), $this->emptyLine());
+ }
+ }
+
+ function _context($lines) {
+ foreach ($lines as $line) {
+ $this->rows[] = array_merge($this->contextLine(check_plain($line)), $this->contextLine(check_plain($line)));
+ }
+ }
+
+ function _changed($orig, $closing) {
+ $diff = new WordLevelDiff($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 );
+ $this->rows[] = array_merge($this->deletedLine($line), isset($aline) ? $this->addedLine($aline) : $this->emptyLine());
+ }
+ foreach ($add as $line) { // If any leftovers
+ $this->rows[] = array_merge($this->emptyLine(), $this->addedLine($line));
+ }
+ }
+}
+
+/**
+ * Drupal inline Diff formatter.
+ * @private
+ * @subpackage DifferenceEngine
+ */
+class DrupalDiffInline {
+ var $a;
+ var $b;
+
+ /**
+ * Constructor.
+ */
+ function __construct($a, $b) {
+ $this->a = $a;
+ $this->b = $b;
+ }
+
+ /**
+ * Render differences inline using HTML markup.
+ */
+ function render() {
+ $a = preg_split('/(<[^>]+?>| )/', $this->a, -1, PREG_SPLIT_DELIM_CAPTURE);
+ $b = preg_split('/(<[^>]+?>| )/', $this->b, -1, PREG_SPLIT_DELIM_CAPTURE);
+ $diff = new Diff($a, $b);
+ $diff->edits = $this->process_edits($diff->edits);
+
+ // Assemble highlighted output
+ $output = '';
+ foreach ($diff->edits as $chunk) {
+ switch ($chunk->type) {
+ case 'copy':
+ $output .= implode('', $chunk->closing);
+ break;
+ case 'delete':
+ foreach ($chunk->orig as $i => $piece) {
+ if (strpos($piece, '<') === 0 && drupal_substr($piece, drupal_strlen($piece) - 1) === '>') {
+ $output .= $piece;
+ }
+ else {
+ $output .= theme('diff_inline_chunk', array('text' => $piece, 'type' => $chunk->type));
+ }
+ }
+ break;
+ default:
+ $chunk->closing = $this->process_chunk($chunk->closing);
+ foreach ($chunk->closing as $i => $piece) {
+ if ($piece === ' ' || (strpos($piece, '<') === 0 && drupal_substr($piece, drupal_strlen($piece) - 1) === '>' && drupal_strtolower(drupal_substr($piece, 1, 3)) != 'img')) {
+ $output .= $piece;
+ }
+ else {
+ $output .= theme('diff_inline_chunk', array('text' => $piece, 'type' => $chunk->type));
+ }
+ }
+ break;
+ }
+ }
+ return $output;
+ }
+
+ /**
+ * Merge chunk segments between tag delimiters.
+ */
+ function process_chunk($chunk) {
+ $processed = array();
+ $j = 0;
+ foreach ($chunk as $i => $piece) {
+ $next = isset($chunk[$i+1]) ? $chunk[$i+1] : NULL;
+ if (!isset($processed[$j])) {
+ $processed[$j] = '';
+ }
+ if (strpos($piece, '<') === 0 && drupal_substr($piece, drupal_strlen($piece) - 1) === '>') {
+ $processed[$j] = $piece;
+ $j++;
+ }
+ elseif (isset($next) && strpos($next, '<') === 0 && drupal_substr($next, drupal_strlen($next) - 1) === '>') {
+ $processed[$j] .= $piece;
+ $j++;
+ }
+ else {
+ $processed[$j] .= $piece;
+ }
+ }
+ return $processed;
+ }
+
+ /**
+ * Merge copy and equivalent edits into intelligible chunks.
+ */
+ function process_edits($edits) {
+ $processed = array();
+ $current = array_shift($edits);
+
+ // Make two passes -- first merge space delimiter copies back into their originals.
+ while ($chunk = array_shift($edits)) {
+ if ($chunk->type == 'copy' && $chunk->orig === array(' ')) {
+ $current->orig = array_merge((array) $current->orig, (array) $chunk->orig);
+ $current->closing = array_merge((array) $current->closing, (array) $chunk->closing);
+ }
+ else {
+ $processed[] = $current;
+ $current = $chunk;
+ }
+ }
+ $processed[] = $current;
+
+ // Initial setup
+ $edits = $processed;
+ $processed = array();
+ $current = array_shift($edits);
+
+ // Second, merge equivalent chunks into each other.
+ while ($chunk = array_shift($edits)) {
+ if ($current->type == $chunk->type) {
+ $current->orig = array_merge((array) $current->orig, (array) $chunk->orig);
+ $current->closing = array_merge((array) $current->closing, (array) $chunk->closing);
+ }
+ else {
+ $processed[] = $current;
+ $current = $chunk;
+ }
+ }
+ $processed[] = $current;
+
+ return $processed;
+ }
+}