Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit unpack-trees: don't shift conflicts left and right (603d249)
   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, $symlinks) = @_;
  89        my $null_sha1 = '0' x 40;
  90
  91        if ($sha1 ne $null_sha1 and not $symlinks) {
  92                return 0;
  93        }
  94
  95        if (! -e "$workdir/$file") {
  96                # If the file doesn't exist in the working tree, we cannot
  97                # use it.
  98                return (0, $null_sha1);
  99        }
 100
 101        my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
 102        my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
 103        return ($use, $wt_sha1);
 104}
 105
 106sub changed_files
 107{
 108        my ($repo_path, $index, $worktree) = @_;
 109        $ENV{GIT_INDEX_FILE} = $index;
 110        $ENV{GIT_WORK_TREE} = $worktree;
 111        my $must_unset_git_dir = 0;
 112        if (not defined($ENV{GIT_DIR})) {
 113                $must_unset_git_dir = 1;
 114                $ENV{GIT_DIR} = $repo_path;
 115        }
 116
 117        my @refreshargs = qw/update-index --really-refresh -q --unmerged/;
 118        my @gitargs = qw/diff-files --name-only -z/;
 119        try {
 120                Git::command_oneline(@refreshargs);
 121        } catch Git::Error::Command with {};
 122
 123        my $line = Git::command_oneline(@gitargs);
 124        my @files;
 125        if (defined $line) {
 126                @files = split('\0', $line);
 127        } else {
 128                @files = ();
 129        }
 130
 131        delete($ENV{GIT_INDEX_FILE});
 132        delete($ENV{GIT_WORK_TREE});
 133        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 134
 135        return map { $_ => 1 } @files;
 136}
 137
 138sub setup_dir_diff
 139{
 140        my ($repo, $workdir, $symlinks) = @_;
 141
 142        # Run the diff; exit immediately if no diff found
 143        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 144        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 145        # by Git->repository->command*.
 146        my $repo_path = $repo->repo_path();
 147        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
 148        my $diffrepo = Git->repository(%repo_args);
 149
 150        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 151        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 152        exit(0) unless defined($diffrtn);
 153
 154        # Build index info for left and right sides of the diff
 155        my $submodule_mode = '160000';
 156        my $symlink_mode = '120000';
 157        my $null_mode = '0' x 6;
 158        my $null_sha1 = '0' x 40;
 159        my $lindex = '';
 160        my $rindex = '';
 161        my $wtindex = '';
 162        my %submodule;
 163        my %symlink;
 164        my @working_tree = ();
 165        my @rawdiff = split('\0', $diffrtn);
 166
 167        my $i = 0;
 168        while ($i < $#rawdiff) {
 169                if ($rawdiff[$i] =~ /^::/) {
 170                        warn << 'EOF';
 171Combined diff formats ('-c' and '--cc') are not supported in
 172directory diff mode ('-d' and '--dir-diff').
 173EOF
 174                        exit(1);
 175                }
 176
 177                my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 178                        split(' ', substr($rawdiff[$i], 1));
 179                my $src_path = $rawdiff[$i + 1];
 180                my $dst_path;
 181
 182                if ($status =~ /^[CR]/) {
 183                        $dst_path = $rawdiff[$i + 2];
 184                        $i += 3;
 185                } else {
 186                        $dst_path = $src_path;
 187                        $i += 2;
 188                }
 189
 190                if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 191                        $submodule{$src_path}{left} = $lsha1;
 192                        if ($lsha1 ne $rsha1) {
 193                                $submodule{$dst_path}{right} = $rsha1;
 194                        } else {
 195                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 196                        }
 197                        next;
 198                }
 199
 200                if ($lmode eq $symlink_mode) {
 201                        $symlink{$src_path}{left} =
 202                                $diffrepo->command_oneline('show', "$lsha1");
 203                }
 204
 205                if ($rmode eq $symlink_mode) {
 206                        $symlink{$dst_path}{right} =
 207                                $diffrepo->command_oneline('show', "$rsha1");
 208                }
 209
 210                if ($lmode ne $null_mode and $status !~ /^C/) {
 211                        $lindex .= "$lmode $lsha1\t$src_path\0";
 212                }
 213
 214                if ($rmode ne $null_mode) {
 215                        my ($use, $wt_sha1) = use_wt_file($repo, $workdir,
 216                                                          $dst_path, $rsha1,
 217                                                          $symlinks);
 218                        if ($use) {
 219                                push @working_tree, $dst_path;
 220                                $wtindex .= "$rmode $wt_sha1\t$dst_path\0";
 221                        } else {
 222                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 223                        }
 224                }
 225        }
 226
 227        # Setup temp directories
 228        my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
 229        my $ldir = "$tmpdir/left";
 230        my $rdir = "$tmpdir/right";
 231        mkpath($ldir) or exit_cleanup($tmpdir, 1);
 232        mkpath($rdir) or exit_cleanup($tmpdir, 1);
 233
 234        # If $GIT_DIR is not set prior to calling 'git update-index' and
 235        # 'git checkout-index', then those commands will fail if difftool
 236        # is called from a directory other than the repo root.
 237        my $must_unset_git_dir = 0;
 238        if (not defined($ENV{GIT_DIR})) {
 239                $must_unset_git_dir = 1;
 240                $ENV{GIT_DIR} = $repo_path;
 241        }
 242
 243        # Populate the left and right directories based on each index file
 244        my ($inpipe, $ctx);
 245        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 246        ($inpipe, $ctx) =
 247                $repo->command_input_pipe(qw(update-index -z --index-info));
 248        print($inpipe $lindex);
 249        $repo->command_close_pipe($inpipe, $ctx);
 250
 251        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 252        exit_cleanup($tmpdir, $rc) if $rc != 0;
 253
 254        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 255        ($inpipe, $ctx) =
 256                $repo->command_input_pipe(qw(update-index -z --index-info));
 257        print($inpipe $rindex);
 258        $repo->command_close_pipe($inpipe, $ctx);
 259
 260        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 261        exit_cleanup($tmpdir, $rc) if $rc != 0;
 262
 263        $ENV{GIT_INDEX_FILE} = "$tmpdir/wtindex";
 264        ($inpipe, $ctx) =
 265                $repo->command_input_pipe(qw(update-index --info-only -z --index-info));
 266        print($inpipe $wtindex);
 267        $repo->command_close_pipe($inpipe, $ctx);
 268
 269        # If $GIT_DIR was explicitly set just for the update/checkout
 270        # commands, then it should be unset before continuing.
 271        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 272        delete($ENV{GIT_INDEX_FILE});
 273
 274        # Changes in the working tree need special treatment since they are
 275        # not part of the index. Remove any trailing slash from $workdir
 276        # before starting to avoid double slashes in symlink targets.
 277        $workdir =~ s|/$||;
 278        for my $file (@working_tree) {
 279                my $dir = dirname($file);
 280                unless (-d "$rdir/$dir") {
 281                        mkpath("$rdir/$dir") or
 282                        exit_cleanup($tmpdir, 1);
 283                }
 284                if ($symlinks) {
 285                        symlink("$workdir/$file", "$rdir/$file") or
 286                        exit_cleanup($tmpdir, 1);
 287                } else {
 288                        copy("$workdir/$file", "$rdir/$file") or
 289                        exit_cleanup($tmpdir, 1);
 290
 291                        my $mode = stat("$workdir/$file")->mode;
 292                        chmod($mode, "$rdir/$file") or
 293                        exit_cleanup($tmpdir, 1);
 294                }
 295        }
 296
 297        # Changes to submodules require special treatment. This loop writes a
 298        # temporary file to both the left and right directories to show the
 299        # change in the recorded SHA1 for the submodule.
 300        for my $path (keys %submodule) {
 301                my $ok;
 302                if (defined($submodule{$path}{left})) {
 303                        $ok = write_to_file("$ldir/$path",
 304                                "Subproject commit $submodule{$path}{left}");
 305                }
 306                if (defined($submodule{$path}{right})) {
 307                        $ok = write_to_file("$rdir/$path",
 308                                "Subproject commit $submodule{$path}{right}");
 309                }
 310                exit_cleanup($tmpdir, 1) if not $ok;
 311        }
 312
 313        # Symbolic links require special treatment. The standard "git diff"
 314        # shows only the link itself, not the contents of the link target.
 315        # This loop replicates that behavior.
 316        for my $path (keys %symlink) {
 317                my $ok;
 318                if (defined($symlink{$path}{left})) {
 319                        $ok = write_to_file("$ldir/$path",
 320                                        $symlink{$path}{left});
 321                }
 322                if (defined($symlink{$path}{right})) {
 323                        $ok = write_to_file("$rdir/$path",
 324                                        $symlink{$path}{right});
 325                }
 326                exit_cleanup($tmpdir, 1) if not $ok;
 327        }
 328
 329        return ($ldir, $rdir, $tmpdir, @working_tree);
 330}
 331
 332sub write_to_file
 333{
 334        my $path = shift;
 335        my $value = shift;
 336
 337        # Make sure the path to the file exists
 338        my $dir = dirname($path);
 339        unless (-d "$dir") {
 340                mkpath("$dir") or return 0;
 341        }
 342
 343        # If the file already exists in that location, delete it.  This
 344        # is required in the case of symbolic links.
 345        unlink($path);
 346
 347        open(my $fh, '>', $path) or return 0;
 348        print($fh $value);
 349        close($fh);
 350
 351        return 1;
 352}
 353
 354sub main
 355{
 356        # parse command-line options. all unrecognized options and arguments
 357        # are passed through to the 'git diff' command.
 358        my %opts = (
 359                difftool_cmd => undef,
 360                dirdiff => undef,
 361                extcmd => undef,
 362                gui => undef,
 363                help => undef,
 364                prompt => undef,
 365                symlinks => $^O ne 'cygwin' &&
 366                                $^O ne 'MSWin32' && $^O ne 'msys',
 367                tool_help => undef,
 368        );
 369        GetOptions('g|gui!' => \$opts{gui},
 370                'd|dir-diff' => \$opts{dirdiff},
 371                'h' => \$opts{help},
 372                'prompt!' => \$opts{prompt},
 373                'y' => sub { $opts{prompt} = 0; },
 374                'symlinks' => \$opts{symlinks},
 375                'no-symlinks' => sub { $opts{symlinks} = 0; },
 376                't|tool:s' => \$opts{difftool_cmd},
 377                'tool-help' => \$opts{tool_help},
 378                'x|extcmd:s' => \$opts{extcmd});
 379
 380        if (defined($opts{help})) {
 381                usage(0);
 382        }
 383        if (defined($opts{tool_help})) {
 384                print_tool_help();
 385        }
 386        if (defined($opts{difftool_cmd})) {
 387                if (length($opts{difftool_cmd}) > 0) {
 388                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 389                } else {
 390                        print "No <tool> given for --tool=<tool>\n";
 391                        usage(1);
 392                }
 393        }
 394        if (defined($opts{extcmd})) {
 395                if (length($opts{extcmd}) > 0) {
 396                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 397                } else {
 398                        print "No <cmd> given for --extcmd=<cmd>\n";
 399                        usage(1);
 400                }
 401        }
 402        if ($opts{gui}) {
 403                my $guitool = Git::config('diff.guitool');
 404                if (defined($guitool) && length($guitool) > 0) {
 405                        $ENV{GIT_DIFF_TOOL} = $guitool;
 406                }
 407        }
 408
 409        # In directory diff mode, 'git-difftool--helper' is called once
 410        # to compare the a/b directories.  In file diff mode, 'git diff'
 411        # will invoke a separate instance of 'git-difftool--helper' for
 412        # each file that changed.
 413        if (defined($opts{dirdiff})) {
 414                dir_diff($opts{extcmd}, $opts{symlinks});
 415        } else {
 416                file_diff($opts{prompt});
 417        }
 418}
 419
 420sub dir_diff
 421{
 422        my ($extcmd, $symlinks) = @_;
 423        my $rc;
 424        my $error = 0;
 425        my $repo = Git->repository();
 426        my $workdir = find_worktree($repo);
 427        my ($a, $b, $tmpdir, @worktree) =
 428                setup_dir_diff($repo, $workdir, $symlinks);
 429
 430        if (defined($extcmd)) {
 431                $rc = system($extcmd, $a, $b);
 432        } else {
 433                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 434                $rc = system('git', 'difftool--helper', $a, $b);
 435        }
 436        # If the diff including working copy files and those
 437        # files were modified during the diff, then the changes
 438        # should be copied back to the working tree.
 439        # Do not copy back files when symlinks are used and the
 440        # external tool did not replace the original link with a file.
 441        #
 442        # These hashes are loaded lazily since they aren't needed
 443        # in the common case of --symlinks and the difftool updating
 444        # files through the symlink.
 445        my %wt_modified;
 446        my %tmp_modified;
 447        my $indices_loaded = 0;
 448
 449        for my $file (@worktree) {
 450                next if $symlinks && -l "$b/$file";
 451                next if ! -f "$b/$file";
 452
 453                if (!$indices_loaded) {
 454                        %wt_modified = changed_files($repo->repo_path(),
 455                                "$tmpdir/wtindex", "$workdir");
 456                        %tmp_modified = changed_files($repo->repo_path(),
 457                                "$tmpdir/wtindex", "$b");
 458                        $indices_loaded = 1;
 459                }
 460
 461                if (exists $wt_modified{$file} and exists $tmp_modified{$file}) {
 462                        my $errmsg = "warning: Both files modified: ";
 463                        $errmsg .= "'$workdir/$file' and '$b/$file'.\n";
 464                        $errmsg .= "warning: Working tree file has been left.\n";
 465                        $errmsg .= "warning:\n";
 466                        warn $errmsg;
 467                        $error = 1;
 468                } elsif (exists $tmp_modified{$file}) {
 469                        my $mode = stat("$b/$file")->mode;
 470                        copy("$b/$file", "$workdir/$file") or
 471                        exit_cleanup($tmpdir, 1);
 472
 473                        chmod($mode, "$workdir/$file") or
 474                        exit_cleanup($tmpdir, 1);
 475                }
 476        }
 477        if ($error) {
 478                warn "warning: Temporary files exist in '$tmpdir'.\n";
 479                warn "warning: You may want to cleanup or recover these.\n";
 480                exit(1);
 481        } else {
 482                exit_cleanup($tmpdir, $rc);
 483        }
 484}
 485
 486sub file_diff
 487{
 488        my ($prompt) = @_;
 489
 490        if (defined($prompt)) {
 491                if ($prompt) {
 492                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 493                } else {
 494                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 495                }
 496        }
 497
 498        $ENV{GIT_PAGER} = '';
 499        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 500
 501        # ActiveState Perl for Win32 does not implement POSIX semantics of
 502        # exec* system call. It just spawns the given executable and finishes
 503        # the starting program, exiting with code 0.
 504        # system will at least catch the errors returned by git diff,
 505        # allowing the caller of git difftool better handling of failures.
 506        my $rc = system('git', 'diff', @ARGV);
 507        exit($rc | ($rc >> 8));
 508}
 509
 510main();