--- /dev/null
+shebang.perl
+diff-highlight
--- /dev/null
+package DiffHighlight;
+
+use 5.008;
+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 @OLD_HIGHLIGHT = (
+ color_config('color.diff-highlight.oldnormal'),
+ color_config('color.diff-highlight.oldhighlight', "\x1b[7m"),
+ color_config('color.diff-highlight.oldreset', "\x1b[27m")
+);
+my @NEW_HIGHLIGHT = (
+ color_config('color.diff-highlight.newnormal', $OLD_HIGHLIGHT[0]),
+ color_config('color.diff-highlight.newhighlight', $OLD_HIGHLIGHT[1]),
+ color_config('color.diff-highlight.newreset', $OLD_HIGHLIGHT[2])
+);
+
+my $RESET = "\x1b[m";
+my $COLOR = qr/\x1b\[[0-9;]*m/;
+my $BORING = qr/$COLOR|\s/;
+
+# The patch portion of git log -p --graph should only ever have preceding | and
+# not / or \ as merge history only shows up on the commit line.
+my $GRAPH = qr/$COLOR?\|$COLOR?\s+/;
+
+my @removed;
+my @added;
+my $in_hunk;
+
+our $line_cb = sub { print @_ };
+our $flush_cb = sub { local $| = 1 };
+
+sub handle_line {
+ local $_ = shift;
+
+ if (!$in_hunk) {
+ $line_cb->($_);
+ $in_hunk = /^$GRAPH*$COLOR*\@\@ /;
+ }
+ elsif (/^$GRAPH*$COLOR*-/) {
+ push @removed, $_;
+ }
+ elsif (/^$GRAPH*$COLOR*\+/) {
+ push @added, $_;
+ }
+ else {
+ show_hunk(\@removed, \@added);
+ @removed = ();
+ @added = ();
+
+ $line_cb->($_);
+ $in_hunk = /^$GRAPH*$COLOR*[\@ ]/;
+ }
+
+ # 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) {
+ $flush_cb->();
+ }
+}
+
+sub flush {
+ # Flush any queued hunk (this can happen when there is no trailing
+ # context in the final diff of the input).
+ show_hunk(\@removed, \@added);
+}
+
+sub highlight_stdin {
+ while (<STDIN>) {
+ handle_line($_);
+ }
+ flush();
+}
+
+# Ideally we would feed the default as a human-readable color to
+# git-config as the fallback value. But diff-highlight does
+# not otherwise depend on git at all, and there are reports
+# of it being used in other settings. Let's handle our own
+# fallback, which means we will work even if git can't be run.
+sub color_config {
+ my ($key, $default) = @_;
+ my $s = `git config --get-color $key 2>/dev/null`;
+ return length($s) ? $s : $default;
+}
+
+sub show_hunk {
+ my ($a, $b) = @_;
+
+ # If one side is empty, then there is nothing to compare or highlight.
+ if (!@$a || !@$b) {
+ $line_cb->(@$a, @$b);
+ return;
+ }
+
+ # If we have mismatched numbers of lines on each side, we could try to
+ # be clever and match up similar lines. But for now we are simple and
+ # stupid, and only handle multi-line hunks that remove and add the same
+ # number of lines.
+ if (@$a != @$b) {
+ $line_cb->(@$a, @$b);
+ return;
+ }
+
+ my @queue;
+ for (my $i = 0; $i < @$a; $i++) {
+ my ($rm, $add) = highlight_pair($a->[$i], $b->[$i]);
+ $line_cb->($rm);
+ push @queue, $add;
+ }
+ $line_cb->(@queue);
+}
+
+sub highlight_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;
+ }
+ }
+
+ if (is_pair_interesting(\@a, $pa, $sa, \@b, $pb, $sb)) {
+ return highlight_line(\@a, $pa, $sa, \@OLD_HIGHLIGHT),
+ highlight_line(\@b, $pb, $sb, \@NEW_HIGHLIGHT);
+ }
+ else {
+ return join('', @a),
+ join('', @b);
+ }
+}
+
+# we split either by $COLOR or by character. This has the side effect of
+# leaving in graph cruft. It works because the graph cruft does not contain "-"
+# or "+"
+sub split_line {
+ local $_ = shift;
+ return utf8::decode($_) ?
+ map { utf8::encode($_); $_ }
+ map { /$COLOR/ ? $_ : (split //) }
+ split /($COLOR+)/ :
+ map { /$COLOR/ ? $_ : (split //) }
+ split /($COLOR+)/;
+}
+
+sub highlight_line {
+ my ($line, $prefix, $suffix, $theme) = @_;
+
+ my $start = join('', @{$line}[0..($prefix-1)]);
+ my $mid = join('', @{$line}[$prefix..$suffix]);
+ my $end = join('', @{$line}[($suffix+1)..$#$line]);
+
+ # If we have a "normal" color specified, then take over the whole line.
+ # Otherwise, we try to just manipulate the highlighted bits.
+ if (defined $theme->[0]) {
+ s/$COLOR//g for ($start, $mid, $end);
+ chomp $end;
+ return join('',
+ $theme->[0], $start, $RESET,
+ $theme->[1], $mid, $RESET,
+ $theme->[0], $end, $RESET,
+ "\n"
+ );
+ } else {
+ return join('',
+ $start,
+ $theme->[1], $mid, $theme->[2],
+ $end
+ );
+ }
+}
+
+# Pairs are interesting to highlight only if we are going to end up
+# highlighting a subset (i.e., not the whole line). Otherwise, the highlighting
+# is just useless noise. We can detect this by finding either a matching prefix
+# or suffix (disregarding boring bits like whitespace and colorization).
+sub is_pair_interesting {
+ my ($a, $pa, $sa, $b, $pb, $sb) = @_;
+ my $prefix_a = join('', @$a[0..($pa-1)]);
+ my $prefix_b = join('', @$b[0..($pb-1)]);
+ my $suffix_a = join('', @$a[($sa+1)..$#$a]);
+ my $suffix_b = join('', @$b[($sb+1)..$#$b]);
+
+ return $prefix_a !~ /^$GRAPH*$COLOR*-$BORING*$/ ||
+ $prefix_b !~ /^$GRAPH*$COLOR*\+$BORING*$/ ||
+ $suffix_a !~ /^$BORING*$/ ||
+ $suffix_b !~ /^$BORING*$/;
+}
-# nothing to build
-all:
+all: diff-highlight
-test:
+PERL_PATH = /usr/bin/perl
+-include ../../config.mak
+
+PERL_PATH_SQ = $(subst ','\'',$(PERL_PATH))
+
+diff-highlight: shebang.perl DiffHighlight.pm diff-highlight.perl
+ cat $^ >$@+
+ chmod +x $@+
+ mv $@+ $@
+
+shebang.perl: FORCE
+ @echo '#!$(PERL_PATH_SQ)' >$@+
+ @cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@
+
+test: all
$(MAKE) -C t
+
+.PHONY: FORCE
---------------------------------------------
+Using diff-highlight as a module
+--------------------------------
+
+If you want to pre- or post- process the highlighted lines as part of
+another perl script, you can use the DiffHighlight module. You can
+either "require" it or just cat the module together with your script (to
+avoid run-time dependencies).
+
+Your script may set up one or more of the following variables:
+
+ - $DiffHighlight::line_cb - this should point to a function which is
+ called whenever DiffHighlight has lines (which may contain
+ highlights) to output. The default function prints each line to
+ stdout. Note that the function may be called with multiple lines.
+
+ - $DiffHighlight::flush_cb - this should point to a function which
+ flushes the output (because DiffHighlight believes it has completed
+ processing a logical chunk of input). The default function flushes
+ stdout.
+
+The script may then feed lines, one at a time, to DiffHighlight::handle_line().
+When lines are done processing, they will be fed to $line_cb. Note that
+DiffHighlight may queue up many input lines (to analyze a whole hunk)
+before calling $line_cb. After providing all lines, call
+DiffHighlight::flush() to flush any unprocessed lines.
+
+If you just want to process stdin, DiffHighlight::highlight_stdin()
+is a convenience helper which will loop and flush for you.
+
+
Bugs
----
+++ /dev/null
-#!/usr/bin/perl
-
-use 5.008;
-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 @OLD_HIGHLIGHT = (
- color_config('color.diff-highlight.oldnormal'),
- color_config('color.diff-highlight.oldhighlight', "\x1b[7m"),
- color_config('color.diff-highlight.oldreset', "\x1b[27m")
-);
-my @NEW_HIGHLIGHT = (
- color_config('color.diff-highlight.newnormal', $OLD_HIGHLIGHT[0]),
- color_config('color.diff-highlight.newhighlight', $OLD_HIGHLIGHT[1]),
- color_config('color.diff-highlight.newreset', $OLD_HIGHLIGHT[2])
-);
-
-my $RESET = "\x1b[m";
-my $COLOR = qr/\x1b\[[0-9;]*m/;
-my $BORING = qr/$COLOR|\s/;
-
-# The patch portion of git log -p --graph should only ever have preceding | and
-# not / or \ as merge history only shows up on the commit line.
-my $GRAPH = qr/$COLOR?\|$COLOR?\s+/;
-
-my @removed;
-my @added;
-my $in_hunk;
-
-# Some scripts may not realize that SIGPIPE is being ignored when launching the
-# pager--for instance scripts written in Python.
-$SIG{PIPE} = 'DEFAULT';
-
-while (<>) {
- if (!$in_hunk) {
- print;
- $in_hunk = /^$GRAPH*$COLOR*\@\@ /;
- }
- elsif (/^$GRAPH*$COLOR*-/) {
- push @removed, $_;
- }
- elsif (/^$GRAPH*$COLOR*\+/) {
- push @added, $_;
- }
- else {
- show_hunk(\@removed, \@added);
- @removed = ();
- @added = ();
-
- print;
- $in_hunk = /^$GRAPH*$COLOR*[\@ ]/;
- }
-
- # 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 $| = 1;
- }
-}
-
-# Flush any queued hunk (this can happen when there is no trailing context in
-# the final diff of the input).
-show_hunk(\@removed, \@added);
-
-exit 0;
-
-# Ideally we would feed the default as a human-readable color to
-# git-config as the fallback value. But diff-highlight does
-# not otherwise depend on git at all, and there are reports
-# of it being used in other settings. Let's handle our own
-# fallback, which means we will work even if git can't be run.
-sub color_config {
- my ($key, $default) = @_;
- my $s = `git config --get-color $key 2>/dev/null`;
- return length($s) ? $s : $default;
-}
-
-sub show_hunk {
- my ($a, $b) = @_;
-
- # If one side is empty, then there is nothing to compare or highlight.
- if (!@$a || !@$b) {
- print @$a, @$b;
- return;
- }
-
- # If we have mismatched numbers of lines on each side, we could try to
- # be clever and match up similar lines. But for now we are simple and
- # stupid, and only handle multi-line hunks that remove and add the same
- # number of lines.
- if (@$a != @$b) {
- print @$a, @$b;
- return;
- }
-
- my @queue;
- for (my $i = 0; $i < @$a; $i++) {
- my ($rm, $add) = highlight_pair($a->[$i], $b->[$i]);
- print $rm;
- push @queue, $add;
- }
- print @queue;
-}
-
-sub highlight_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;
- }
- }
-
- if (is_pair_interesting(\@a, $pa, $sa, \@b, $pb, $sb)) {
- return highlight_line(\@a, $pa, $sa, \@OLD_HIGHLIGHT),
- highlight_line(\@b, $pb, $sb, \@NEW_HIGHLIGHT);
- }
- else {
- return join('', @a),
- join('', @b);
- }
-}
-
-# we split either by $COLOR or by character. This has the side effect of
-# leaving in graph cruft. It works because the graph cruft does not contain "-"
-# or "+"
-sub split_line {
- local $_ = shift;
- return utf8::decode($_) ?
- map { utf8::encode($_); $_ }
- map { /$COLOR/ ? $_ : (split //) }
- split /($COLOR+)/ :
- map { /$COLOR/ ? $_ : (split //) }
- split /($COLOR+)/;
-}
-
-sub highlight_line {
- my ($line, $prefix, $suffix, $theme) = @_;
-
- my $start = join('', @{$line}[0..($prefix-1)]);
- my $mid = join('', @{$line}[$prefix..$suffix]);
- my $end = join('', @{$line}[($suffix+1)..$#$line]);
-
- # If we have a "normal" color specified, then take over the whole line.
- # Otherwise, we try to just manipulate the highlighted bits.
- if (defined $theme->[0]) {
- s/$COLOR//g for ($start, $mid, $end);
- chomp $end;
- return join('',
- $theme->[0], $start, $RESET,
- $theme->[1], $mid, $RESET,
- $theme->[0], $end, $RESET,
- "\n"
- );
- } else {
- return join('',
- $start,
- $theme->[1], $mid, $theme->[2],
- $end
- );
- }
-}
-
-# Pairs are interesting to highlight only if we are going to end up
-# highlighting a subset (i.e., not the whole line). Otherwise, the highlighting
-# is just useless noise. We can detect this by finding either a matching prefix
-# or suffix (disregarding boring bits like whitespace and colorization).
-sub is_pair_interesting {
- my ($a, $pa, $sa, $b, $pb, $sb) = @_;
- my $prefix_a = join('', @$a[0..($pa-1)]);
- my $prefix_b = join('', @$b[0..($pb-1)]);
- my $suffix_a = join('', @$a[($sa+1)..$#$a]);
- my $suffix_b = join('', @$b[($sb+1)..$#$b]);
-
- return $prefix_a !~ /^$GRAPH*$COLOR*-$BORING*$/ ||
- $prefix_b !~ /^$GRAPH*$COLOR*\+$BORING*$/ ||
- $suffix_a !~ /^$BORING*$/ ||
- $suffix_b !~ /^$BORING*$/;
-}
--- /dev/null
+package main;
+
+# Some scripts may not realize that SIGPIPE is being ignored when launching the
+# pager--for instance scripts written in Python.
+$SIG{PIPE} = 'DEFAULT';
+
+DiffHighlight::highlight_stdin();
+exit 0;