#!/usr/bin/perl
use lib (split(/:/, $ENV{GITPERLLIB} || "/usr/share/perl5"));
# Copyright (c) 2009, 2010 David Aguilar
# Copyright (c) 2012 Tim Henigan
#
# This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
# git-difftool--helper script.
#
# This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
# The GIT_DIFF* variables are exported for use by git-difftool--helper.
#
# Any arguments that are unknown to this script are forwarded to 'git diff'.
use 5.008;
use strict;
use warnings;
use Error qw(:try);
use File::Basename qw(dirname);
use File::Copy;
use File::Find;
use File::stat;
use File::Path qw(mkpath rmtree);
use File::Temp qw(tempdir);
use Getopt::Long qw(:config pass_through);
use Git;
sub usage
{
my $exitcode = shift;
print << 'USAGE';
usage: git difftool [-t|--tool=<tool>] [--tool-help]
[-x|--extcmd=<cmd>]
[-g|--gui] [--no-gui]
[--prompt] [-y|--no-prompt]
[-d|--dir-diff]
['git diff' options]
USAGE
exit($exitcode);
}
sub find_worktree
{
my ($repo) = @_;
# Git->repository->wc_path() does not honor changes to the working
# tree location made by $ENV{GIT_WORK_TREE} or the 'core.worktree'
# config variable.
my $worktree;
my $env_worktree = $ENV{GIT_WORK_TREE};
my $core_worktree = Git::config('core.worktree');
if (defined($env_worktree) and (length($env_worktree) > 0)) {
$worktree = $env_worktree;
} elsif (defined($core_worktree) and (length($core_worktree) > 0)) {
$worktree = $core_worktree;
} else {
$worktree = $repo->wc_path();
}
return $worktree;
}
sub print_tool_help
{
my $cmd = 'TOOL_MODE=diff';
$cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
$cmd .= ' && show_tool_help';
# See the comment at the bottom of file_diff() for the reason behind
# using system() followed by exit() instead of exec().
my $rc = system('sh', '-c', $cmd);
exit($rc | ($rc >> 8));
}
sub exit_cleanup
{
my ($tmpdir, $status) = @_;
my $errno = $!;
rmtree($tmpdir);
if ($status and $errno) {
my ($package, $file, $line) = caller();
warn "$file line $line: $errno\n";
}
exit($status | ($status >> 8));
}
sub use_wt_file
{
my ($repo, $workdir, $file, $sha1, $symlinks) = @_;
my $null_sha1 = '0' x 40;
if ($sha1 ne $null_sha1 and not $symlinks) {
return 0;
}
if (! -e "$workdir/$file") {
# If the file doesn't exist in the working tree, we cannot
# use it.
return (0, $null_sha1);
}
my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
return ($use, $wt_sha1);
}
sub changed_files
{
my ($repo_path, $index, $worktree) = @_;
$ENV{GIT_INDEX_FILE} = $index;
$ENV{GIT_WORK_TREE} = $worktree;
my $must_unset_git_dir = 0;
if (not defined($ENV{GIT_DIR})) {
$must_unset_git_dir = 1;
$ENV{GIT_DIR} = $repo_path;
}
my @refreshargs = qw/update-index --really-refresh -q --unmerged/;
my @gitargs = qw/diff-files --name-only -z/;
try {
Git::command_oneline(@refreshargs);
} catch Git::Error::Command with {};
my $line = Git::command_oneline(@gitargs);
my @files;
if (defined $line) {
@files = split('\0', $line);
} else {
@files = ();
}
delete($ENV{GIT_INDEX_FILE});
delete($ENV{GIT_WORK_TREE});
delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
return map { $_ => 1 } @files;
}
sub setup_dir_diff
{
my ($repo, $workdir, $symlinks) = @_;
# Run the diff; exit immediately if no diff found
# 'Repository' and 'WorkingCopy' must be explicitly set to insure that
# if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
# by Git->repository->command*.
my $repo_path = $repo->repo_path();
my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
my $diffrepo = Git->repository(%repo_args);
my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
my $diffrtn = $diffrepo->command_oneline(@gitargs);
exit(0) unless defined($diffrtn);
# Build index info for left and right sides of the diff
my $submodule_mode = '160000';
my $symlink_mode = '120000';
my $null_mode = '0' x 6;
my $null_sha1 = '0' x 40;
my $lindex = '';
my $rindex = '';
my $wtindex = '';
my %submodule;
my %symlink;
my @working_tree = ();
my @rawdiff = split('\0', $diffrtn);
my $i = 0;
while ($i < $#rawdiff) {
if ($rawdiff[$i] =~ /^::/) {
warn << 'EOF';
Combined diff formats ('-c' and '--cc') are not supported in
directory diff mode ('-d' and '--dir-diff').
EOF
exit(1);
}
my ($lmode, $rmode, $lsha1, $rsha1, $status) =
split(' ', substr($rawdiff[$i], 1));
my $src_path = $rawdiff[$i + 1];
my $dst_path;
if ($status =~ /^[CR]/) {
$dst_path = $rawdiff[$i + 2];
$i += 3;
} else {
$dst_path = $src_path;
$i += 2;
}
if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
$submodule{$src_path}{left} = $lsha1;
if ($lsha1 ne $rsha1) {
$submodule{$dst_path}{right} = $rsha1;
} else {
$submodule{$dst_path}{right} = "$rsha1-dirty";
}
next;
}
if ($lmode eq $symlink_mode) {
$symlink{$src_path}{left} =
$diffrepo->command_oneline('show', "$lsha1");
}
if ($rmode eq $symlink_mode) {
$symlink{$dst_path}{right} =
$diffrepo->command_oneline('show', "$rsha1");
}
if ($lmode ne $null_mode and $status !~ /^C/) {
$lindex .= "$lmode $lsha1\t$src_path\0";
}
if ($rmode ne $null_mode) {
my ($use, $wt_sha1) = use_wt_file($repo, $workdir,
$dst_path, $rsha1,
$symlinks);
if ($use) {
push @working_tree, $dst_path;
$wtindex .= "$rmode $wt_sha1\t$dst_path\0";
} else {
$rindex .= "$rmode $rsha1\t$dst_path\0";
}
}
}
# Setup temp directories
my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
my $ldir = "$tmpdir/left";
my $rdir = "$tmpdir/right";
mkpath($ldir) or exit_cleanup($tmpdir, 1);
mkpath($rdir) or exit_cleanup($tmpdir, 1);
# If $GIT_DIR is not set prior to calling 'git update-index' and
# 'git checkout-index', then those commands will fail if difftool
# is called from a directory other than the repo root.
my $must_unset_git_dir = 0;
if (not defined($ENV{GIT_DIR})) {
$must_unset_git_dir = 1;
$ENV{GIT_DIR} = $repo_path;
}
# Populate the left and right directories based on each index file
my ($inpipe, $ctx);
$ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
($inpipe, $ctx) =
$repo->command_input_pipe(qw(update-index -z --index-info));
print($inpipe $lindex);
$repo->command_close_pipe($inpipe, $ctx);
my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
exit_cleanup($tmpdir, $rc) if $rc != 0;
$ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
($inpipe, $ctx) =
$repo->command_input_pipe(qw(update-index -z --index-info));
print($inpipe $rindex);
$repo->command_close_pipe($inpipe, $ctx);
$rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
exit_cleanup($tmpdir, $rc) if $rc != 0;
$ENV{GIT_INDEX_FILE} = "$tmpdir/wtindex";
($inpipe, $ctx) =
$repo->command_input_pipe(qw(update-index --info-only -z --index-info));
print($inpipe $wtindex);
$repo->command_close_pipe($inpipe, $ctx);
# If $GIT_DIR was explicitly set just for the update/checkout
# commands, then it should be unset before continuing.
delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
delete($ENV{GIT_INDEX_FILE});
# Changes in the working tree need special treatment since they are
# not part of the index. Remove any trailing slash from $workdir
# before starting to avoid double slashes in symlink targets.
$workdir =~ s|/$||;
for my $file (@working_tree) {
my $dir = dirname($file);
unless (-d "$rdir/$dir") {
mkpath("$rdir/$dir") or
exit_cleanup($tmpdir, 1);
}
if ($symlinks) {
symlink("$workdir/$file", "$rdir/$file") or
exit_cleanup($tmpdir, 1);
} else {
copy("$workdir/$file", "$rdir/$file") or
exit_cleanup($tmpdir, 1);
my $mode = stat("$workdir/$file")->mode;
chmod($mode, "$rdir/$file") or
exit_cleanup($tmpdir, 1);
}
}
# Changes to submodules require special treatment. This loop writes a
# temporary file to both the left and right directories to show the
# change in the recorded SHA1 for the submodule.
for my $path (keys %submodule) {
my $ok;
if (defined($submodule{$path}{left})) {
$ok = write_to_file("$ldir/$path",
"Subproject commit $submodule{$path}{left}");
}
if (defined($submodule{$path}{right})) {
$ok = write_to_file("$rdir/$path",
"Subproject commit $submodule{$path}{right}");
}
exit_cleanup($tmpdir, 1) if not $ok;
}
# Symbolic links require special treatment. The standard "git diff"
# shows only the link itself, not the contents of the link target.
# This loop replicates that behavior.
for my $path (keys %symlink) {
my $ok;
if (defined($symlink{$path}{left})) {
$ok = write_to_file("$ldir/$path",
$symlink{$path}{left});
}
if (defined($symlink{$path}{right})) {
$ok = write_to_file("$rdir/$path",
$symlink{$path}{right});
}
exit_cleanup($tmpdir, 1) if not $ok;
}
return ($ldir, $rdir, $tmpdir, @working_tree);
}
sub write_to_file
{
my $path = shift;
my $value = shift;
# Make sure the path to the file exists
my $dir = dirname($path);
unless (-d "$dir") {
mkpath("$dir") or return 0;
}
# If the file already exists in that location, delete it. This
# is required in the case of symbolic links.
unlink($path);
open(my $fh, '>', $path) or return 0;
print($fh $value);
close($fh);
return 1;
}
sub main
{
# parse command-line options. all unrecognized options and arguments
# are passed through to the 'git diff' command.
my %opts = (
difftool_cmd => undef,
dirdiff => undef,
extcmd => undef,
gui => undef,
help => undef,
prompt => undef,
symlinks => $^O ne 'cygwin' &&
$^O ne 'MSWin32' && $^O ne 'msys',
tool_help => undef,
);
GetOptions('g|gui!' => \$opts{gui},
'd|dir-diff' => \$opts{dirdiff},
'h' => \$opts{help},
'prompt!' => \$opts{prompt},
'y' => sub { $opts{prompt} = 0; },
'symlinks' => \$opts{symlinks},
'no-symlinks' => sub { $opts{symlinks} = 0; },
't|tool:s' => \$opts{difftool_cmd},
'tool-help' => \$opts{tool_help},
'x|extcmd:s' => \$opts{extcmd});
if (defined($opts{help})) {
usage(0);
}
if (defined($opts{tool_help})) {
print_tool_help();
}
if (defined($opts{difftool_cmd})) {
if (length($opts{difftool_cmd}) > 0) {
$ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
} else {
print "No <tool> given for --tool=<tool>\n";
usage(1);
}
}
if (defined($opts{extcmd})) {
if (length($opts{extcmd}) > 0) {
$ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
} else {
print "No <cmd> given for --extcmd=<cmd>\n";
usage(1);
}
}
if ($opts{gui}) {
my $guitool = Git::config('diff.guitool');
if (defined($guitool) && length($guitool) > 0) {
$ENV{GIT_DIFF_TOOL} = $guitool;
}
}
# In directory diff mode, 'git-difftool--helper' is called once
# to compare the a/b directories. In file diff mode, 'git diff'
# will invoke a separate instance of 'git-difftool--helper' for
# each file that changed.
if (defined($opts{dirdiff})) {
dir_diff($opts{extcmd}, $opts{symlinks});
} else {
file_diff($opts{prompt});
}
}
sub dir_diff
{
my ($extcmd, $symlinks) = @_;
my $rc;
my $error = 0;
my $repo = Git->repository();
my $workdir = find_worktree($repo);
my ($a, $b, $tmpdir, @worktree) =
setup_dir_diff($repo, $workdir, $symlinks);
if (defined($extcmd)) {
$rc = system($extcmd, $a, $b);
} else {
$ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
$rc = system('git', 'difftool--helper', $a, $b);
}
# If the diff including working copy files and those
# files were modified during the diff, then the changes
# should be copied back to the working tree.
# Do not copy back files when symlinks are used and the
# external tool did not replace the original link with a file.
#
# These hashes are loaded lazily since they aren't needed
# in the common case of --symlinks and the difftool updating
# files through the symlink.
my %wt_modified;
my %tmp_modified;
my $indices_loaded = 0;
for my $file (@worktree) {
next if $symlinks && -l "$b/$file";
next if ! -f "$b/$file";
if (!$indices_loaded) {
%wt_modified = changed_files($repo->repo_path(),
"$tmpdir/wtindex", "$workdir");
%tmp_modified = changed_files($repo->repo_path(),
"$tmpdir/wtindex", "$b");
$indices_loaded = 1;
}
if (exists $wt_modified{$file} and exists $tmp_modified{$file}) {
my $errmsg = "warning: Both files modified: ";
$errmsg .= "'$workdir/$file' and '$b/$file'.\n";
$errmsg .= "warning: Working tree file has been left.\n";
$errmsg .= "warning:\n";
warn $errmsg;
$error = 1;
} elsif (exists $tmp_modified{$file}) {
my $mode = stat("$b/$file")->mode;
copy("$b/$file", "$workdir/$file") or
exit_cleanup($tmpdir, 1);
chmod($mode, "$workdir/$file") or
exit_cleanup($tmpdir, 1);
}
}
if ($error) {
warn "warning: Temporary files exist in '$tmpdir'.\n";
warn "warning: You may want to cleanup or recover these.\n";
exit(1);
} else {
exit_cleanup($tmpdir, $rc);
}
}
sub file_diff
{
my ($prompt) = @_;
if (defined($prompt)) {
if ($prompt) {
$ENV{GIT_DIFFTOOL_PROMPT} = 'true';
} else {
$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
}
}
$ENV{GIT_PAGER} = '';
$ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
# ActiveState Perl for Win32 does not implement POSIX semantics of
# exec* system call. It just spawns the given executable and finishes
# the starting program, exiting with code 0.
# system will at least catch the errors returned by git diff,
# allowing the caller of git difftool better handling of failures.
my $rc = system('git', 'diff', @ARGV);
exit($rc | ($rc >> 8));
}
main();