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