git instaweb: enable remote_heads
[git] / git-difftool.perl
1 #!/usr/bin/env perl
2 # Copyright (c) 2009, 2010 David Aguilar
3 #
4 # This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
5 # git-difftool--helper script.
6 #
7 # This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
8 # GIT_DIFFTOOL_NO_PROMPT, GIT_DIFFTOOL_PROMPT, and GIT_DIFF_TOOL
9 # are exported for use by git-difftool--helper.
10 #
11 # Any arguments that are unknown to this script are forwarded to 'git diff'.
12
13 use 5.008;
14 use strict;
15 use warnings;
16 use Cwd qw(abs_path);
17 use File::Basename qw(dirname);
18
19 require Git;
20
21 my $DIR = abs_path(dirname($0));
22
23
24 sub usage
25 {
26         print << 'USAGE';
27 usage: git difftool [-t|--tool=<tool>] [-x|--extcmd=<cmd>]
28                     [-y|--no-prompt]   [-g|--gui]
29                     ['git diff' options]
30 USAGE
31         exit 1;
32 }
33
34 sub setup_environment
35 {
36         $ENV{PATH} = "$DIR:$ENV{PATH}";
37         $ENV{GIT_PAGER} = '';
38         $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
39 }
40
41 sub exe
42 {
43         my $exe = shift;
44         if ($^O eq 'MSWin32' || $^O eq 'msys') {
45                 return "$exe.exe";
46         }
47         return $exe;
48 }
49
50 sub generate_command
51 {
52         my @command = (exe('git'), 'diff');
53         my $skip_next = 0;
54         my $idx = -1;
55         for my $arg (@ARGV) {
56                 $idx++;
57                 if ($skip_next) {
58                         $skip_next = 0;
59                         next;
60                 }
61                 if ($arg eq '-t' || $arg eq '--tool') {
62                         usage() if $#ARGV <= $idx;
63                         $ENV{GIT_DIFF_TOOL} = $ARGV[$idx + 1];
64                         $skip_next = 1;
65                         next;
66                 }
67                 if ($arg =~ /^--tool=/) {
68                         $ENV{GIT_DIFF_TOOL} = substr($arg, 7);
69                         next;
70                 }
71                 if ($arg eq '-x' || $arg eq '--extcmd') {
72                         usage() if $#ARGV <= $idx;
73                         $ENV{GIT_DIFFTOOL_EXTCMD} = $ARGV[$idx + 1];
74                         $skip_next = 1;
75                         next;
76                 }
77                 if ($arg =~ /^--extcmd=/) {
78                         $ENV{GIT_DIFFTOOL_EXTCMD} = substr($arg, 9);
79                         next;
80                 }
81                 if ($arg eq '-g' || $arg eq '--gui') {
82                         eval {
83                                 my $tool = Git::command_oneline('config',
84                                                                 'diff.guitool');
85                                 if (length($tool)) {
86                                         $ENV{GIT_DIFF_TOOL} = $tool;
87                                 }
88                         };
89                         next;
90                 }
91                 if ($arg eq '-y' || $arg eq '--no-prompt') {
92                         $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
93                         delete $ENV{GIT_DIFFTOOL_PROMPT};
94                         next;
95                 }
96                 if ($arg eq '--prompt') {
97                         $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
98                         delete $ENV{GIT_DIFFTOOL_NO_PROMPT};
99                         next;
100                 }
101                 if ($arg eq '-h' || $arg eq '--help') {
102                         usage();
103                 }
104                 push @command, $arg;
105         }
106         return @command
107 }
108
109 setup_environment();
110
111 # ActiveState Perl for Win32 does not implement POSIX semantics of
112 # exec* system call. It just spawns the given executable and finishes
113 # the starting program, exiting with code 0.
114 # system will at least catch the errors returned by git diff,
115 # allowing the caller of git difftool better handling of failures.
116 my $rc = system(generate_command());
117 exit($rc | ($rc >> 8));