git-difftool.perl

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