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