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Commit | Line | Data |
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927a13fe JK |
1 | #!/usr/bin/perl |
2 | ||
3 | # Highlight by reversing foreground and background. You could do | |
4 | # other things like bold or underline if you prefer. | |
5 | my $HIGHLIGHT = "\x1b[7m"; | |
6 | my $UNHIGHLIGHT = "\x1b[27m"; | |
7 | my $COLOR = qr/\x1b\[[0-9;]*m/; | |
8 | ||
9 | my @window; | |
10 | ||
11 | while (<>) { | |
12 | # We highlight only single-line changes, so we need | |
13 | # a 4-line window to make a decision on whether | |
14 | # to highlight. | |
15 | push @window, $_; | |
16 | next if @window < 4; | |
17 | if ($window[0] =~ /^$COLOR*(\@| )/ && | |
18 | $window[1] =~ /^$COLOR*-/ && | |
19 | $window[2] =~ /^$COLOR*\+/ && | |
20 | $window[3] !~ /^$COLOR*\+/) { | |
21 | print shift @window; | |
22 | show_pair(shift @window, shift @window); | |
23 | } | |
24 | else { | |
25 | print shift @window; | |
26 | } | |
27 | ||
28 | # Most of the time there is enough output to keep things streaming, | |
29 | # but for something like "git log -Sfoo", you can get one early | |
30 | # commit and then many seconds of nothing. We want to show | |
31 | # that one commit as soon as possible. | |
32 | # | |
33 | # Since we can receive arbitrary input, there's no optimal | |
34 | # place to flush. Flushing on a blank line is a heuristic that | |
35 | # happens to match git-log output. | |
36 | if (!length) { | |
37 | local $| = 1; | |
38 | } | |
39 | } | |
40 | ||
41 | # Special case a single-line hunk at the end of file. | |
42 | if (@window == 3 && | |
43 | $window[0] =~ /^$COLOR*(\@| )/ && | |
44 | $window[1] =~ /^$COLOR*-/ && | |
45 | $window[2] =~ /^$COLOR*\+/) { | |
46 | print shift @window; | |
47 | show_pair(shift @window, shift @window); | |
48 | } | |
49 | ||
50 | # And then flush any remaining lines. | |
51 | while (@window) { | |
52 | print shift @window; | |
53 | } | |
54 | ||
55 | exit 0; | |
56 | ||
57 | sub show_pair { | |
58 | my @a = split_line(shift); | |
59 | my @b = split_line(shift); | |
60 | ||
61 | # Find common prefix, taking care to skip any ansi | |
62 | # color codes. | |
63 | my $seen_plusminus; | |
64 | my ($pa, $pb) = (0, 0); | |
65 | while ($pa < @a && $pb < @b) { | |
66 | if ($a[$pa] =~ /$COLOR/) { | |
67 | $pa++; | |
68 | } | |
69 | elsif ($b[$pb] =~ /$COLOR/) { | |
70 | $pb++; | |
71 | } | |
72 | elsif ($a[$pa] eq $b[$pb]) { | |
73 | $pa++; | |
74 | $pb++; | |
75 | } | |
76 | elsif (!$seen_plusminus && $a[$pa] eq '-' && $b[$pb] eq '+') { | |
77 | $seen_plusminus = 1; | |
78 | $pa++; | |
79 | $pb++; | |
80 | } | |
81 | else { | |
82 | last; | |
83 | } | |
84 | } | |
85 | ||
86 | # Find common suffix, ignoring colors. | |
87 | my ($sa, $sb) = ($#a, $#b); | |
88 | while ($sa >= $pa && $sb >= $pb) { | |
89 | if ($a[$sa] =~ /$COLOR/) { | |
90 | $sa--; | |
91 | } | |
92 | elsif ($b[$sb] =~ /$COLOR/) { | |
93 | $sb--; | |
94 | } | |
95 | elsif ($a[$sa] eq $b[$sb]) { | |
96 | $sa--; | |
97 | $sb--; | |
98 | } | |
99 | else { | |
100 | last; | |
101 | } | |
102 | } | |
103 | ||
104 | print highlight(\@a, $pa, $sa); | |
105 | print highlight(\@b, $pb, $sb); | |
106 | } | |
107 | ||
108 | sub split_line { | |
109 | local $_ = shift; | |
110 | return map { /$COLOR/ ? $_ : (split //) } | |
111 | split /($COLOR*)/; | |
112 | } | |
113 | ||
114 | sub highlight { | |
115 | my ($line, $prefix, $suffix) = @_; | |
116 | ||
117 | return join('', | |
118 | @{$line}[0..($prefix-1)], | |
119 | $HIGHLIGHT, | |
120 | @{$line}[$prefix..$suffix], | |
121 | $UNHIGHLIGHT, | |
122 | @{$line}[($suffix+1)..$#$line] | |
123 | ); | |
124 | } |