<?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.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @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 );
}
/**
* @return int
*/
function norig() {
return $this->orig ? count( $this->orig ) : 0;
}
/**
* @return int
*/
function nclosing() {
return $this->closing ? count( $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;
}
/**
* @return _DiffOp_Copy
*/
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;
}
/**
* @return _DiffOp_Add
*/
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;
}
/**
* @return _DiffOp_Delete
*/
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;
}
/**
* @return _DiffOp_Change
*/
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;
protected $xchanged, $ychanged;
protected $xv = array(), $yv = array();
protected $xind = array(), $yind = array();
protected $seq = array(), $in_seq = array();
protected $lcs = 0;
/**
* @param $from_lines
* @param $to_lines
* @return array
*/
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 = count( $from_lines );
$n_to = count( $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;
}
/**
* @param $from_lines
* @param $to_lines
*/
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 = count( $from_lines );
$n_to = count( $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, count( $this->xv ), 0, count( $this->yv ) );
}
wfProfileOut( __METHOD__ );
}
/**
* Returns the whole line if it's small enough, or the MD5 hash otherwise
* @param $line string
* @return string
*/
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.
* @param $xoff
* @param $xlim
* @param $yoff
* @param $ylim
* @param $nchunks
* @return array
*/
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( , $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( , $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;
} elseif ( 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 );
}
/**
* @param $ypos
* @return int
*/
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.
* @param $xoff
* @param $xlim
* @param $yoff
* @param $ylim
*/
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;
$j = 0;
assert( 'count($lines) == count($changed)' );
$len = count( $lines );
$other_len = count( $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 if 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 += count( $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, count( $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, count( $lines ), 0, $edit->closing );
}
}
return $lines;
}
/**
* Check a Diff for validity.
*
* This is here only for debugging purposes.
* @param $from_lines
* @param $to_lines
*/
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( 'count( $from_lines ) == count( $mapped_from_lines )' );
assert( 'count( $to_lines ) == count( $mapped_to_lines )' );
parent::__construct( $mapped_from_lines, $mapped_to_lines );
$xi = $yi = 0;
for ( $i = 0; $i < count( $this->edits ); $i++ ) {
$orig = &$this->edits[$i]->orig;
if ( is_array( $orig ) ) {
$orig = array_slice( $from_lines, $xi, count( $orig ) );
$xi += count( $orig );
}
$closing = &$this->edits[$i]->closing;
if ( is_array( $closing ) ) {
$closing = array_slice( $to_lines, $yi, count( $closing ) );
$yi += count( $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 Diff 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 ( count( $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, count( $context ) - $nlead );
$x0 = $xi - count( $context );
$y0 = $yi - count( $context );
$block = array();
if ( $context ) {
$block[] = new _DiffOp_Copy( $context );
}
}
$block[] = $edit;
}
if ( $edit->orig ) {
$xi += count( $edit->orig );
}
if ( $edit->closing ) {
$yi += count( $edit->closing );
}
}
if ( is_array( $block ) ) {
$this->_block( $x0, $xi - $x0,
$y0, $yi - $y0,
$block );
}
$end = $this->_end_diff();
wfProfileOut( __METHOD__ );
return $end;
}
/**
* @param $xbeg
* @param $xlen
* @param $ybeg
* @param $ylen
* @param $edits
*/
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();
}
/**
* @return string
*/
function _end_diff() {
$val = ob_get_contents();
ob_end_clean();
return $val;
}
/**
* @param $xbeg
* @param $xlen
* @param $ybeg
* @param $ylen
* @return string
*/
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() {
}
/**
* @param $lines
* @param $prefix string
*/
function _lines( $lines, $prefix = ' ' ) {
foreach ( $lines as $line ) {
echo "$prefix $line\n";
}
}
/**
* @param $lines
*/
function _context( $lines ) {
$this->_lines( $lines );
}
/**
* @param $lines
*/
function _added( $lines ) {
$this->_lines( $lines, '>' );
}
/**
* @param $lines
*/
function _deleted( $lines ) {
$this->_lines( $lines, '<' );
}
/**
* @param $orig
* @param $closing
*/
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;
/**
* @param $lines
*/
function _added( $lines ) {
$this->_lines( $lines, '+' );
}
/**
* @param $lines
*/
function _deleted( $lines ) {
$this->_lines( $lines, '-' );
}
/**
* @param $orig
* @param $closing
*/
function _changed( $orig, $closing ) {
$this->_deleted( $orig );
$this->_added( $closing );
}
/**
* @param $xbeg
* @param $xlen
* @param $ybeg
* @param $ylen
* @return string
*/
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 {
/**
* @param $diff
* @return array
*/
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' => isset( $edit->closing[$i] ) ? $edit->closing[$i] : null,
'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 = '';
}
/**
* @param $new_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;
}
/**
* @param $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 = '';
}
/**
* @param $words
* @param $tag string
*/
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;
}
}
/**
* @return array
*/
function getLines() {
$this->_flushLine( '~done' );
return $this->_lines;
}
}
/**
* @todo document
* @private
* @ingroup DifferenceEngine
*/
class WordLevelDiff extends MappedDiff {
const MAX_LINE_LENGTH = 10000;
/**
* @param $orig_lines
* @param $closing_lines
*/
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__ );
}
/**
* @param $lines
* @return array
*/
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 ) )
{
foreach ( $m[0] as $word ) {
$words[] = $word;
}
foreach ( $m[1] as $stripped_word ) {
$stripped[] = $stripped_word;
}
}
}
}
wfProfileOut( __METHOD__ );
return array( $words, $stripped );
}
/**
* @return array
*/
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;
}
/**
* @return array
*/
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;
}
/**
* @static
* @param $msg
* @return mixed
*/
public static function escapeWhiteSpace( $msg ) {
$msg = preg_replace( '/^ /m', '  ', $msg );
$msg = preg_replace( '/ $/m', '  ', $msg );
$msg = preg_replace( '/ /', '  ', $msg );
return $msg;
}
/**
* @param $xbeg
* @param $xlen
* @param $ybeg
* @param $ylen
* @return string
*/
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;
}
/**
* @param $header
*/
function _start_block( $header ) {
echo $header;
}
function _end_block() {
}
function _lines( $lines, $prefix = ' ', $color = 'white' ) {
}
/**
* HTML-escape parameter before calling this
* @param $line
* @return string
*/
function addedLine( $line ) {
return $this->wrapLine( '+', 'diff-addedline', $line );
}
/**
* HTML-escape parameter before calling this
* @param $line
* @return string
*/
function deletedLine( $line ) {
return $this->wrapLine( '−', 'diff-deletedline', $line );
}
/**
* HTML-escape parameter before calling this
* @param $line
* @return string
*/
function contextLine( $line ) {
return $this->wrapLine( ' ', 'diff-context', $line );
}
/**
* @param $marker
* @param $class
* @param $line
* @return string
*/
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>";
}
/**
* @return string
*/
function emptyLine() {
return '<td colspan="2"> </td>';
}
/**
* @param $lines array
*/
function _added( $lines ) {
foreach ( $lines as $line ) {
echo '<tr>' . $this->emptyLine() .
$this->addedLine( '<ins class="diffchange">' .
htmlspecialchars( $line ) . '</ins>' ) . "</tr>\n";
}
}
/**
* @param $lines
*/
function _deleted( $lines ) {
foreach ( $lines as $line ) {
echo '<tr>' . $this->deletedLine( '<del class="diffchange">' .
htmlspecialchars( $line ) . '</del>' ) .
$this->emptyLine() . "</tr>\n";
}
}
/**
* @param $lines
*/
function _context( $lines ) {
foreach ( $lines as $line ) {
echo '<tr>' .
$this->contextLine( htmlspecialchars( $line ) ) .
$this->contextLine( htmlspecialchars( $line ) ) . "</tr>\n";
}
}
/**
* @param $orig
* @param $closing
*/
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__ );
}
}