Files
git/contrib/diff-highlight/diff-highlight
Jeff King 2b21008d3c diff-highlight: make perl strict and warnings fatal
These perl features can catch bugs, and we shouldn't be
violating any of the strict rules or creating any warnings,
so let's turn them on.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-02-13 15:57:06 -08:00

128 lines
2.6 KiB
Perl
Executable File

#!/usr/bin/perl
use warnings FATAL => 'all';
use strict;
# Highlight by reversing foreground and background. You could do
# other things like bold or underline if you prefer.
my $HIGHLIGHT = "\x1b[7m";
my $UNHIGHLIGHT = "\x1b[27m";
my $COLOR = qr/\x1b\[[0-9;]*m/;
my @window;
while (<>) {
# We highlight only single-line changes, so we need
# a 4-line window to make a decision on whether
# to highlight.
push @window, $_;
next if @window < 4;
if ($window[0] =~ /^$COLOR*(\@| )/ &&
$window[1] =~ /^$COLOR*-/ &&
$window[2] =~ /^$COLOR*\+/ &&
$window[3] !~ /^$COLOR*\+/) {
print shift @window;
show_pair(shift @window, shift @window);
}
else {
print shift @window;
}
# Most of the time there is enough output to keep things streaming,
# but for something like "git log -Sfoo", you can get one early
# commit and then many seconds of nothing. We want to show
# that one commit as soon as possible.
#
# Since we can receive arbitrary input, there's no optimal
# place to flush. Flushing on a blank line is a heuristic that
# happens to match git-log output.
if (!length) {
local $| = 1;
}
}
# Special case a single-line hunk at the end of file.
if (@window == 3 &&
$window[0] =~ /^$COLOR*(\@| )/ &&
$window[1] =~ /^$COLOR*-/ &&
$window[2] =~ /^$COLOR*\+/) {
print shift @window;
show_pair(shift @window, shift @window);
}
# And then flush any remaining lines.
while (@window) {
print shift @window;
}
exit 0;
sub show_pair {
my @a = split_line(shift);
my @b = split_line(shift);
# Find common prefix, taking care to skip any ansi
# color codes.
my $seen_plusminus;
my ($pa, $pb) = (0, 0);
while ($pa < @a && $pb < @b) {
if ($a[$pa] =~ /$COLOR/) {
$pa++;
}
elsif ($b[$pb] =~ /$COLOR/) {
$pb++;
}
elsif ($a[$pa] eq $b[$pb]) {
$pa++;
$pb++;
}
elsif (!$seen_plusminus && $a[$pa] eq '-' && $b[$pb] eq '+') {
$seen_plusminus = 1;
$pa++;
$pb++;
}
else {
last;
}
}
# Find common suffix, ignoring colors.
my ($sa, $sb) = ($#a, $#b);
while ($sa >= $pa && $sb >= $pb) {
if ($a[$sa] =~ /$COLOR/) {
$sa--;
}
elsif ($b[$sb] =~ /$COLOR/) {
$sb--;
}
elsif ($a[$sa] eq $b[$sb]) {
$sa--;
$sb--;
}
else {
last;
}
}
print highlight(\@a, $pa, $sa);
print highlight(\@b, $pb, $sb);
}
sub split_line {
local $_ = shift;
return map { /$COLOR/ ? $_ : (split //) }
split /($COLOR*)/;
}
sub highlight {
my ($line, $prefix, $suffix) = @_;
return join('',
@{$line}[0..($prefix-1)],
$HIGHLIGHT,
@{$line}[$prefix..$suffix],
$UNHIGHLIGHT,
@{$line}[($suffix+1)..$#$line]
);
}