Andrew's git - gitweb.git/blob

   1#!/usr/bin/perl
   2# Copyright (c) 2009, 2010 David Aguilar
   3# Copyright (c) 2012 Tim Henigan
   4#
   5# This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
   6# git-difftool--helper script.
   7#
   8# This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
   9# The GIT_DIFF* variables are exported for use by git-difftool--helper.
  10#
  11# Any arguments that are unknown to this script are forwarded to 'git diff'.
  12
  13use 5.008;
  14use strict;
  15use warnings;
  16use Error qw(:try);
  17use File::Basename qw(dirname);
  18use File::Copy;
  19use File::Find;
  20use File::stat;
  21use File::Path qw(mkpath rmtree);
  22use File::Temp qw(tempdir);
  23use Getopt::Long qw(:config pass_through);
  24use Git;
  25
  26sub usage
  27{
  28        my $exitcode = shift;
  29        print << 'USAGE';
  30usage: git difftool [-t|--tool=<tool>] [--tool-help]
  31                    [-x|--extcmd=<cmd>]
  32                    [-g|--gui] [--no-gui]
  33                    [--prompt] [-y|--no-prompt]
  34                    [-d|--dir-diff]
  35                    ['git diff' options]
  36USAGE
  37        exit($exitcode);
  38}
  39
  40sub find_worktree
  41{
  42        my ($repo) = @_;
  43
  44        # Git->repository->wc_path() does not honor changes to the working
  45        # tree location made by $ENV{GIT_WORK_TREE} or the 'core.worktree'
  46        # config variable.
  47        my $worktree;
  48        my $env_worktree = $ENV{GIT_WORK_TREE};
  49        my $core_worktree = Git::config('core.worktree');
  50
  51        if (defined($env_worktree) and (length($env_worktree) > 0)) {
  52                $worktree = $env_worktree;
  53        } elsif (defined($core_worktree) and (length($core_worktree) > 0)) {
  54                $worktree = $core_worktree;
  55        } else {
  56                $worktree = $repo->wc_path();
  57        }
  58
  59        return $worktree;
  60}
  61
  62sub print_tool_help
  63{
  64        my $cmd = 'TOOL_MODE=diff';
  65        $cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
  66        $cmd .= ' && show_tool_help';
  67
  68        # See the comment at the bottom of file_diff() for the reason behind
  69        # using system() followed by exit() instead of exec().
  70        my $rc = system('sh', '-c', $cmd);
  71        exit($rc | ($rc >> 8));
  72}
  73
  74sub exit_cleanup
  75{
  76        my ($tmpdir, $status) = @_;
  77        my $errno = $!;
  78        rmtree($tmpdir);
  79        if ($status and $errno) {
  80                my ($package, $file, $line) = caller();
  81                warn "$file line $line: $errno\n";
  82        }
  83        exit($status | ($status >> 8));
  84}
  85
  86sub use_wt_file
  87{
  88        my ($repo, $workdir, $file, $sha1) = @_;
  89        my $null_sha1 = '0' x 40;
  90
  91        if (! -e "$workdir/$file") {
  92                # If the file doesn't exist in the working tree, we cannot
  93                # use it.
  94                return (0, $null_sha1);
  95        }
  96
  97        my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
  98        my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
  99        return ($use, $wt_sha1);
 100}
 101
 102sub changed_files
 103{
 104        my ($repo_path, $index, $worktree) = @_;
 105        $ENV{GIT_INDEX_FILE} = $index;
 106        $ENV{GIT_WORK_TREE} = $worktree;
 107        my $must_unset_git_dir = 0;
 108        if (not defined($ENV{GIT_DIR})) {
 109                $must_unset_git_dir = 1;
 110                $ENV{GIT_DIR} = $repo_path;
 111        }
 112
 113        my @refreshargs = qw/update-index --really-refresh -q --unmerged/;
 114        my @gitargs = qw/diff-files --name-only -z/;
 115        try {
 116                Git::command_oneline(@refreshargs);
 117        } catch Git::Error::Command with {};
 118
 119        my $line = Git::command_oneline(@gitargs);
 120        my @files;
 121        if (defined $line) {
 122                @files = split('\0', $line);
 123        } else {
 124                @files = ();
 125        }
 126
 127        delete($ENV{GIT_INDEX_FILE});
 128        delete($ENV{GIT_WORK_TREE});
 129        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 130
 131        return map { $_ => 1 } @files;
 132}
 133
 134sub setup_dir_diff
 135{
 136        my ($repo, $workdir, $symlinks) = @_;
 137
 138        # Run the diff; exit immediately if no diff found
 139        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 140        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 141        # by Git->repository->command*.
 142        my $repo_path = $repo->repo_path();
 143        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
 144        my $diffrepo = Git->repository(%repo_args);
 145
 146        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 147        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 148        exit(0) unless defined($diffrtn);
 149
 150        # Build index info for left and right sides of the diff
 151        my $submodule_mode = '160000';
 152        my $symlink_mode = '120000';
 153        my $null_mode = '0' x 6;
 154        my $null_sha1 = '0' x 40;
 155        my $lindex = '';
 156        my $rindex = '';
 157        my $wtindex = '';
 158        my %submodule;
 159        my %symlink;
 160        my @working_tree = ();
 161        my @rawdiff = split('\0', $diffrtn);
 162
 163        my $i = 0;
 164        while ($i < $#rawdiff) {
 165                if ($rawdiff[$i] =~ /^::/) {
 166                        warn << 'EOF';
 167Combined diff formats ('-c' and '--cc') are not supported in
 168directory diff mode ('-d' and '--dir-diff').
 169EOF
 170                        exit(1);
 171                }
 172
 173                my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 174                        split(' ', substr($rawdiff[$i], 1));
 175                my $src_path = $rawdiff[$i + 1];
 176                my $dst_path;
 177
 178                if ($status =~ /^[CR]/) {
 179                        $dst_path = $rawdiff[$i + 2];
 180                        $i += 3;
 181                } else {
 182                        $dst_path = $src_path;
 183                        $i += 2;
 184                }
 185
 186                if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 187                        $submodule{$src_path}{left} = $lsha1;
 188                        if ($lsha1 ne $rsha1) {
 189                                $submodule{$dst_path}{right} = $rsha1;
 190                        } else {
 191                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 192                        }
 193                        next;
 194                }
 195
 196                if ($lmode eq $symlink_mode) {
 197                        $symlink{$src_path}{left} =
 198                                $diffrepo->command_oneline('show', "$lsha1");
 199                }
 200
 201                if ($rmode eq $symlink_mode) {
 202                        $symlink{$dst_path}{right} =
 203                                $diffrepo->command_oneline('show', "$rsha1");
 204                }
 205
 206                if ($lmode ne $null_mode and $status !~ /^C/) {
 207                        $lindex .= "$lmode $lsha1\t$src_path\0";
 208                }
 209
 210                if ($rmode ne $null_mode) {
 211                        my ($use, $wt_sha1) = use_wt_file($repo, $workdir,
 212                                                          $dst_path, $rsha1);
 213                        if ($use) {
 214                                push @working_tree, $dst_path;
 215                                $wtindex .= "$rmode $wt_sha1\t$dst_path\0";
 216                        } else {
 217                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 218                        }
 219                }
 220        }
 221
 222        # Setup temp directories
 223        my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
 224        my $ldir = "$tmpdir/left";
 225        my $rdir = "$tmpdir/right";
 226        mkpath($ldir) or exit_cleanup($tmpdir, 1);
 227        mkpath($rdir) or exit_cleanup($tmpdir, 1);
 228
 229        # If $GIT_DIR is not set prior to calling 'git update-index' and
 230        # 'git checkout-index', then those commands will fail if difftool
 231        # is called from a directory other than the repo root.
 232        my $must_unset_git_dir = 0;
 233        if (not defined($ENV{GIT_DIR})) {
 234                $must_unset_git_dir = 1;
 235                $ENV{GIT_DIR} = $repo_path;
 236        }
 237
 238        # Populate the left and right directories based on each index file
 239        my ($inpipe, $ctx);
 240        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 241        ($inpipe, $ctx) =
 242                $repo->command_input_pipe(qw(update-index -z --index-info));
 243        print($inpipe $lindex);
 244        $repo->command_close_pipe($inpipe, $ctx);
 245
 246        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 247        exit_cleanup($tmpdir, $rc) if $rc != 0;
 248
 249        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 250        ($inpipe, $ctx) =
 251                $repo->command_input_pipe(qw(update-index -z --index-info));
 252        print($inpipe $rindex);
 253        $repo->command_close_pipe($inpipe, $ctx);
 254
 255        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 256        exit_cleanup($tmpdir, $rc) if $rc != 0;
 257
 258        $ENV{GIT_INDEX_FILE} = "$tmpdir/wtindex";
 259        ($inpipe, $ctx) =
 260                $repo->command_input_pipe(qw(update-index --info-only -z --index-info));
 261        print($inpipe $wtindex);
 262        $repo->command_close_pipe($inpipe, $ctx);
 263
 264        # If $GIT_DIR was explicitly set just for the update/checkout
 265        # commands, then it should be unset before continuing.
 266        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 267        delete($ENV{GIT_INDEX_FILE});
 268
 269        # Changes in the working tree need special treatment since they are
 270        # not part of the index. Remove any trailing slash from $workdir
 271        # before starting to avoid double slashes in symlink targets.
 272        $workdir =~ s|/$||;
 273        for my $file (@working_tree) {
 274                my $dir = dirname($file);
 275                unless (-d "$rdir/$dir") {
 276                        mkpath("$rdir/$dir") or
 277                        exit_cleanup($tmpdir, 1);
 278                }
 279                if ($symlinks) {
 280                        symlink("$workdir/$file", "$rdir/$file") or
 281                        exit_cleanup($tmpdir, 1);
 282                } else {
 283                        copy("$workdir/$file", "$rdir/$file") or
 284                        exit_cleanup($tmpdir, 1);
 285
 286                        my $mode = stat("$workdir/$file")->mode;
 287                        chmod($mode, "$rdir/$file") or
 288                        exit_cleanup($tmpdir, 1);
 289                }
 290        }
 291
 292        # Changes to submodules require special treatment. This loop writes a
 293        # temporary file to both the left and right directories to show the
 294        # change in the recorded SHA1 for the submodule.
 295        for my $path (keys %submodule) {
 296                my $ok;
 297                if (defined($submodule{$path}{left})) {
 298                        $ok = write_to_file("$ldir/$path",
 299                                "Subproject commit $submodule{$path}{left}");
 300                }
 301                if (defined($submodule{$path}{right})) {
 302                        $ok = write_to_file("$rdir/$path",
 303                                "Subproject commit $submodule{$path}{right}");
 304                }
 305                exit_cleanup($tmpdir, 1) if not $ok;
 306        }
 307
 308        # Symbolic links require special treatment. The standard "git diff"
 309        # shows only the link itself, not the contents of the link target.
 310        # This loop replicates that behavior.
 311        for my $path (keys %symlink) {
 312                my $ok;
 313                if (defined($symlink{$path}{left})) {
 314                        $ok = write_to_file("$ldir/$path",
 315                                        $symlink{$path}{left});
 316                }
 317                if (defined($symlink{$path}{right})) {
 318                        $ok = write_to_file("$rdir/$path",
 319                                        $symlink{$path}{right});
 320                }
 321                exit_cleanup($tmpdir, 1) if not $ok;
 322        }
 323
 324        return ($ldir, $rdir, $tmpdir, @working_tree);
 325}
 326
 327sub write_to_file
 328{
 329        my $path = shift;
 330        my $value = shift;
 331
 332        # Make sure the path to the file exists
 333        my $dir = dirname($path);
 334        unless (-d "$dir") {
 335                mkpath("$dir") or return 0;
 336        }
 337
 338        # If the file already exists in that location, delete it.  This
 339        # is required in the case of symbolic links.
 340        unlink($path);
 341
 342        open(my $fh, '>', $path) or return 0;
 343        print($fh $value);
 344        close($fh);
 345
 346        return 1;
 347}
 348
 349sub main
 350{
 351        # parse command-line options. all unrecognized options and arguments
 352        # are passed through to the 'git diff' command.
 353        my %opts = (
 354                difftool_cmd => undef,
 355                dirdiff => undef,
 356                extcmd => undef,
 357                gui => undef,
 358                help => undef,
 359                prompt => undef,
 360                symlinks => $^O ne 'cygwin' &&
 361                                $^O ne 'MSWin32' && $^O ne 'msys',
 362                tool_help => undef,
 363        );
 364        GetOptions('g|gui!' => \$opts{gui},
 365                'd|dir-diff' => \$opts{dirdiff},
 366                'h' => \$opts{help},
 367                'prompt!' => \$opts{prompt},
 368                'y' => sub { $opts{prompt} = 0; },
 369                'symlinks' => \$opts{symlinks},
 370                'no-symlinks' => sub { $opts{symlinks} = 0; },
 371                't|tool:s' => \$opts{difftool_cmd},
 372                'tool-help' => \$opts{tool_help},
 373                'x|extcmd:s' => \$opts{extcmd});
 374
 375        if (defined($opts{help})) {
 376                usage(0);
 377        }
 378        if (defined($opts{tool_help})) {
 379                print_tool_help();
 380        }
 381        if (defined($opts{difftool_cmd})) {
 382                if (length($opts{difftool_cmd}) > 0) {
 383                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 384                } else {
 385                        print "No <tool> given for --tool=<tool>\n";
 386                        usage(1);
 387                }
 388        }
 389        if (defined($opts{extcmd})) {
 390                if (length($opts{extcmd}) > 0) {
 391                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 392                } else {
 393                        print "No <cmd> given for --extcmd=<cmd>\n";
 394                        usage(1);
 395                }
 396        }
 397        if ($opts{gui}) {
 398                my $guitool = Git::config('diff.guitool');
 399                if (defined($guitool) && length($guitool) > 0) {
 400                        $ENV{GIT_DIFF_TOOL} = $guitool;
 401                }
 402        }
 403
 404        # In directory diff mode, 'git-difftool--helper' is called once
 405        # to compare the a/b directories.  In file diff mode, 'git diff'
 406        # will invoke a separate instance of 'git-difftool--helper' for
 407        # each file that changed.
 408        if (defined($opts{dirdiff})) {
 409                dir_diff($opts{extcmd}, $opts{symlinks});
 410        } else {
 411                file_diff($opts{prompt});
 412        }
 413}
 414
 415sub dir_diff
 416{
 417        my ($extcmd, $symlinks) = @_;
 418        my $rc;
 419        my $error = 0;
 420        my $repo = Git->repository();
 421        my $workdir = find_worktree($repo);
 422        my ($a, $b, $tmpdir, @worktree) =
 423                setup_dir_diff($repo, $workdir, $symlinks);
 424
 425        if (defined($extcmd)) {
 426                $rc = system($extcmd, $a, $b);
 427        } else {
 428                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 429                $rc = system('git', 'difftool--helper', $a, $b);
 430        }
 431        # If the diff including working copy files and those
 432        # files were modified during the diff, then the changes
 433        # should be copied back to the working tree.
 434        # Do not copy back files when symlinks are used and the
 435        # external tool did not replace the original link with a file.
 436        #
 437        # These hashes are loaded lazily since they aren't needed
 438        # in the common case of --symlinks and the difftool updating
 439        # files through the symlink.
 440        my %wt_modified;
 441        my %tmp_modified;
 442        my $indices_loaded = 0;
 443
 444        for my $file (@worktree) {
 445                next if $symlinks && -l "$b/$file";
 446                next if ! -f "$b/$file";
 447
 448                if (!$indices_loaded) {
 449                        %wt_modified = changed_files($repo->repo_path(),
 450                                "$tmpdir/wtindex", "$workdir");
 451                        %tmp_modified = changed_files($repo->repo_path(),
 452                                "$tmpdir/wtindex", "$b");
 453                        $indices_loaded = 1;
 454                }
 455
 456                if (exists $wt_modified{$file} and exists $tmp_modified{$file}) {
 457                        my $errmsg = "warning: Both files modified: ";
 458                        $errmsg .= "'$workdir/$file' and '$b/$file'.\n";
 459                        $errmsg .= "warning: Working tree file has been left.\n";
 460                        $errmsg .= "warning:\n";
 461                        warn $errmsg;
 462                        $error = 1;
 463                } elsif (exists $tmp_modified{$file}) {
 464                        my $mode = stat("$b/$file")->mode;
 465                        copy("$b/$file", "$workdir/$file") or
 466                        exit_cleanup($tmpdir, 1);
 467
 468                        chmod($mode, "$workdir/$file") or
 469                        exit_cleanup($tmpdir, 1);
 470                }
 471        }
 472        if ($error) {
 473                warn "warning: Temporary files exist in '$tmpdir'.\n";
 474                warn "warning: You may want to cleanup or recover these.\n";
 475                exit(1);
 476        } else {
 477                exit_cleanup($tmpdir, $rc);
 478        }
 479}
 480
 481sub file_diff
 482{
 483        my ($prompt) = @_;
 484
 485        if (defined($prompt)) {
 486                if ($prompt) {
 487                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 488                } else {
 489                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 490                }
 491        }
 492
 493        $ENV{GIT_PAGER} = '';
 494        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 495
 496        # ActiveState Perl for Win32 does not implement POSIX semantics of
 497        # exec* system call. It just spawns the given executable and finishes
 498        # the starting program, exiting with code 0.
 499        # system will at least catch the errors returned by git diff,
 500        # allowing the caller of git difftool better handling of failures.
 501        my $rc = system('git', 'diff', @ARGV);
 502        exit($rc | ($rc >> 8));
 503}
 504
 505main();