diff options
Diffstat (limited to 'third_party/git/contrib/diff-highlight/DiffHighlight.pm')
| -rw-r--r-- | third_party/git/contrib/diff-highlight/DiffHighlight.pm | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/third_party/git/contrib/diff-highlight/DiffHighlight.pm b/third_party/git/contrib/diff-highlight/DiffHighlight.pm new file mode 100644 index 000000000000..7440aa1c4638 --- /dev/null +++ b/third_party/git/contrib/diff-highlight/DiffHighlight.pm @@ -0,0 +1,285 @@ +package DiffHighlight; + +use 5.008; +use warnings FATAL => 'all'; +use strict; + +# Use the correct value for both UNIX and Windows (/dev/null vs nul) +use File::Spec; + +my $NULL = File::Spec->devnull(); + +# 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/; + +my @removed; +my @added; +my $in_hunk; +my $graph_indent = 0; + +our $line_cb = sub { print @_ }; +our $flush_cb = sub { local $| = 1 }; + +# Count the visible width of a string, excluding any terminal color sequences. +sub visible_width { + local $_ = shift; + my $ret = 0; + while (length) { + if (s/^$COLOR//) { + # skip colors + } elsif (s/^.//) { + $ret++; + } + } + return $ret; +} + +# Return a substring of $str, omitting $len visible characters from the +# beginning, where terminal color sequences do not count as visible. +sub visible_substr { + my ($str, $len) = @_; + while ($len > 0) { + if ($str =~ s/^$COLOR//) { + next + } + $str =~ s/^.//; + $len--; + } + return $str; +} + +sub handle_line { + my $orig = shift; + local $_ = $orig; + + # match a graph line that begins a commit + if (/^(?:$COLOR?\|$COLOR?[ ])* # zero or more leading "|" with space + $COLOR?\*$COLOR?[ ] # a "*" with its trailing space + (?:$COLOR?\|$COLOR?[ ])* # zero or more trailing "|" + [ ]* # trailing whitespace for merges + /x) { + my $graph_prefix = $&; + + # We must flush before setting graph indent, since the + # new commit may be indented differently from what we + # queued. + flush(); + $graph_indent = visible_width($graph_prefix); + + } elsif ($graph_indent) { + if (length($_) < $graph_indent) { + $graph_indent = 0; + } else { + $_ = visible_substr($_, $graph_indent); + } + } + + if (!$in_hunk) { + $line_cb->($orig); + $in_hunk = /^$COLOR*\@\@ /; + } + elsif (/^$COLOR*-/) { + push @removed, $orig; + } + elsif (/^$COLOR*\+/) { + push @added, $orig; + } + else { + flush(); + $line_cb->($orig); + $in_hunk = /^$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) { + $flush_cb->(); + } +} + +sub flush { + # Flush any queued hunk (this can happen when there is no trailing + # context in the final diff of the input). + show_hunk(\@removed, \@added); + @removed = (); + @added = (); +} + +sub highlight_stdin { + while (<STDIN>) { + handle_line($_); + } + 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 $key 2>$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[($sb+1)..$#$b]); + + return visible_substr($prefix_a, $graph_indent) !~ /^$COLOR*-$BORING*$/ || + visible_substr($prefix_b, $graph_indent) !~ /^$COLOR*\+$BORING*$/ || + $suffix_a !~ /^$BORING*$/ || + $suffix_b !~ /^$BORING*$/; +} |