| #!/usr/bin/perl |
| |
| # 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] |
| ); |
| } |