#!/usr/bin/perl # 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) = @_; my $null_sha1 = '0' x 40; if (! -e "$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, $rsha1); if ($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();