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         my $prompt = '';
  56         for my $arg (@ARGV) {
  57                 $idx++;
  58                 if ($skip_next) {
  59                         $skip_next = 0;
  60                         next;
  61                 }
  62                 if ($arg eq '-t' || $arg eq '--tool') {
  63                         usage() if $#ARGV <= $idx;
  64                         $ENV{GIT_DIFF_TOOL} = $ARGV[$idx + 1];
  65                         $skip_next = 1;
  66                         next;
  67                 }
  68                 if ($arg =~ /^--tool=/) {
  69                         $ENV{GIT_DIFF_TOOL} = substr($arg, 7);
  70                         next;
  71                 }
  72                 if ($arg eq '-x' || $arg eq '--extcmd') {
  73                         usage() if $#ARGV <= $idx;
  74                         $ENV{GIT_DIFFTOOL_EXTCMD} = $ARGV[$idx + 1];
  75                         $skip_next = 1;
  76                         next;
  77                 }
  78                 if ($arg =~ /^--extcmd=/) {
  79                         $ENV{GIT_DIFFTOOL_EXTCMD} = substr($arg, 9);
  80                         next;
  81                 }
  82                 if ($arg eq '-g' || $arg eq '--gui') {
  83                         eval {
  84                                 my $tool = Git::command_oneline('config',
  85                                                                 'diff.guitool');
  86                                 if (length($tool)) {
  87                                         $ENV{GIT_DIFF_TOOL} = $tool;
  88                                 }
  89                         };
  90                         next;
  91                 }
  92                 if ($arg eq '-y' || $arg eq '--no-prompt') {
  93                         $prompt = 'no';
  94                         next;
  95                 }
  96                 if ($arg eq '--prompt') {
  97                         $prompt = 'yes';
  98                         next;
  99                 }
 100                 if ($arg eq '-h' || $arg eq '--help') {
 101                         usage();
 102                 }
 103                 push @command, $arg;
 104         }
 105         if ($prompt eq 'yes') {
 106                 $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 107         } elsif ($prompt eq 'no') {
 108                 $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 109         }
 110         return @command
 111 }
 112
 113 setup_environment();
 114
 115 # ActiveState Perl for Win32 does not implement POSIX semantics of
 116 # exec* system call. It just spawns the given executable and finishes
 117 # the starting program, exiting with code 0.
 118 # system will at least catch the errors returned by git diff,
 119 # allowing the caller of git difftool better handling of failures.
 120 my $rc = system(generate_command());
 121 exit($rc | ($rc >> 8));