Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit difftool: ignore symbolic links in use_wt_file (cfe2d4b)
   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        # Git->repository->wc_path() does not honor changes to the working
  43        # tree location made by $ENV{GIT_WORK_TREE} or the 'core.worktree'
  44        # config variable.
  45        return Git::command_oneline('rev-parse', '--show-toplevel');
  46}
  47
  48sub print_tool_help
  49{
  50        # See the comment at the bottom of file_diff() for the reason behind
  51        # using system() followed by exit() instead of exec().
  52        my $rc = system(qw(git mergetool --tool-help=diff));
  53        exit($rc | ($rc >> 8));
  54}
  55
  56sub exit_cleanup
  57{
  58        my ($tmpdir, $status) = @_;
  59        my $errno = $!;
  60        rmtree($tmpdir);
  61        if ($status and $errno) {
  62                my ($package, $file, $line) = caller();
  63                warn "$file line $line: $errno\n";
  64        }
  65        exit($status | ($status >> 8));
  66}
  67
  68sub use_wt_file
  69{
  70        my ($repo, $workdir, $file, $sha1) = @_;
  71        my $null_sha1 = '0' x 40;
  72
  73        if (-l "$workdir/$file" || ! -e _) {
  74                return (0, $null_sha1);
  75        }
  76
  77        my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
  78        my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
  79        return ($use, $wt_sha1);
  80}
  81
  82sub changed_files
  83{
  84        my ($repo_path, $index, $worktree) = @_;
  85        $ENV{GIT_INDEX_FILE} = $index;
  86        $ENV{GIT_WORK_TREE} = $worktree;
  87        my $must_unset_git_dir = 0;
  88        if (not defined($ENV{GIT_DIR})) {
  89                $must_unset_git_dir = 1;
  90                $ENV{GIT_DIR} = $repo_path;
  91        }
  92
  93        my @refreshargs = qw/update-index --really-refresh -q --unmerged/;
  94        my @gitargs = qw/diff-files --name-only -z/;
  95        try {
  96                Git::command_oneline(@refreshargs);
  97        } catch Git::Error::Command with {};
  98
  99        my $line = Git::command_oneline(@gitargs);
 100        my @files;
 101        if (defined $line) {
 102                @files = split('\0', $line);
 103        } else {
 104                @files = ();
 105        }
 106
 107        delete($ENV{GIT_INDEX_FILE});
 108        delete($ENV{GIT_WORK_TREE});
 109        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 110
 111        return map { $_ => 1 } @files;
 112}
 113
 114sub setup_dir_diff
 115{
 116        my ($repo, $workdir, $symlinks) = @_;
 117
 118        # Run the diff; exit immediately if no diff found
 119        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 120        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 121        # by Git->repository->command*.
 122        my $repo_path = $repo->repo_path();
 123        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
 124        my $diffrepo = Git->repository(%repo_args);
 125
 126        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 127        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 128        exit(0) unless defined($diffrtn);
 129
 130        # Build index info for left and right sides of the diff
 131        my $submodule_mode = '160000';
 132        my $symlink_mode = '120000';
 133        my $null_mode = '0' x 6;
 134        my $null_sha1 = '0' x 40;
 135        my $lindex = '';
 136        my $rindex = '';
 137        my $wtindex = '';
 138        my %submodule;
 139        my %symlink;
 140        my @working_tree = ();
 141        my @rawdiff = split('\0', $diffrtn);
 142
 143        my $i = 0;
 144        while ($i < $#rawdiff) {
 145                if ($rawdiff[$i] =~ /^::/) {
 146                        warn << 'EOF';
 147Combined diff formats ('-c' and '--cc') are not supported in
 148directory diff mode ('-d' and '--dir-diff').
 149EOF
 150                        exit(1);
 151                }
 152
 153                my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 154                        split(' ', substr($rawdiff[$i], 1));
 155                my $src_path = $rawdiff[$i + 1];
 156                my $dst_path;
 157
 158                if ($status =~ /^[CR]/) {
 159                        $dst_path = $rawdiff[$i + 2];
 160                        $i += 3;
 161                } else {
 162                        $dst_path = $src_path;
 163                        $i += 2;
 164                }
 165
 166                if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 167                        $submodule{$src_path}{left} = $lsha1;
 168                        if ($lsha1 ne $rsha1) {
 169                                $submodule{$dst_path}{right} = $rsha1;
 170                        } else {
 171                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 172                        }
 173                        next;
 174                }
 175
 176                if ($lmode eq $symlink_mode) {
 177                        $symlink{$src_path}{left} =
 178                                $diffrepo->command_oneline('show', "$lsha1");
 179                }
 180
 181                if ($rmode eq $symlink_mode) {
 182                        $symlink{$dst_path}{right} =
 183                                $diffrepo->command_oneline('show', "$rsha1");
 184                }
 185
 186                if ($lmode ne $null_mode and $status !~ /^C/) {
 187                        $lindex .= "$lmode $lsha1\t$src_path\0";
 188                }
 189
 190                if ($rmode ne $null_mode) {
 191                        my ($use, $wt_sha1) = use_wt_file($repo, $workdir,
 192                                                          $dst_path, $rsha1);
 193                        if ($use) {
 194                                push @working_tree, $dst_path;
 195                                $wtindex .= "$rmode $wt_sha1\t$dst_path\0";
 196                        } else {
 197                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 198                        }
 199                }
 200        }
 201
 202        # Setup temp directories
 203        my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
 204        my $ldir = "$tmpdir/left";
 205        my $rdir = "$tmpdir/right";
 206        mkpath($ldir) or exit_cleanup($tmpdir, 1);
 207        mkpath($rdir) or exit_cleanup($tmpdir, 1);
 208
 209        # If $GIT_DIR is not set prior to calling 'git update-index' and
 210        # 'git checkout-index', then those commands will fail if difftool
 211        # is called from a directory other than the repo root.
 212        my $must_unset_git_dir = 0;
 213        if (not defined($ENV{GIT_DIR})) {
 214                $must_unset_git_dir = 1;
 215                $ENV{GIT_DIR} = $repo_path;
 216        }
 217
 218        # Populate the left and right directories based on each index file
 219        my ($inpipe, $ctx);
 220        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 221        ($inpipe, $ctx) =
 222                $repo->command_input_pipe(qw(update-index -z --index-info));
 223        print($inpipe $lindex);
 224        $repo->command_close_pipe($inpipe, $ctx);
 225
 226        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 227        exit_cleanup($tmpdir, $rc) if $rc != 0;
 228
 229        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 230        ($inpipe, $ctx) =
 231                $repo->command_input_pipe(qw(update-index -z --index-info));
 232        print($inpipe $rindex);
 233        $repo->command_close_pipe($inpipe, $ctx);
 234
 235        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 236        exit_cleanup($tmpdir, $rc) if $rc != 0;
 237
 238        $ENV{GIT_INDEX_FILE} = "$tmpdir/wtindex";
 239        ($inpipe, $ctx) =
 240                $repo->command_input_pipe(qw(update-index --info-only -z --index-info));
 241        print($inpipe $wtindex);
 242        $repo->command_close_pipe($inpipe, $ctx);
 243
 244        # If $GIT_DIR was explicitly set just for the update/checkout
 245        # commands, then it should be unset before continuing.
 246        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 247        delete($ENV{GIT_INDEX_FILE});
 248
 249        # Changes in the working tree need special treatment since they are
 250        # not part of the index. Remove any trailing slash from $workdir
 251        # before starting to avoid double slashes in symlink targets.
 252        $workdir =~ s|/$||;
 253        for my $file (@working_tree) {
 254                my $dir = dirname($file);
 255                unless (-d "$rdir/$dir") {
 256                        mkpath("$rdir/$dir") or
 257                        exit_cleanup($tmpdir, 1);
 258                }
 259                if ($symlinks) {
 260                        symlink("$workdir/$file", "$rdir/$file") or
 261                        exit_cleanup($tmpdir, 1);
 262                } else {
 263                        copy("$workdir/$file", "$rdir/$file") or
 264                        exit_cleanup($tmpdir, 1);
 265
 266                        my $mode = stat("$workdir/$file")->mode;
 267                        chmod($mode, "$rdir/$file") or
 268                        exit_cleanup($tmpdir, 1);
 269                }
 270        }
 271
 272        # Changes to submodules require special treatment. This loop writes a
 273        # temporary file to both the left and right directories to show the
 274        # change in the recorded SHA1 for the submodule.
 275        for my $path (keys %submodule) {
 276                my $ok;
 277                if (defined($submodule{$path}{left})) {
 278                        $ok = write_to_file("$ldir/$path",
 279                                "Subproject commit $submodule{$path}{left}");
 280                }
 281                if (defined($submodule{$path}{right})) {
 282                        $ok = write_to_file("$rdir/$path",
 283                                "Subproject commit $submodule{$path}{right}");
 284                }
 285                exit_cleanup($tmpdir, 1) if not $ok;
 286        }
 287
 288        # Symbolic links require special treatment. The standard "git diff"
 289        # shows only the link itself, not the contents of the link target.
 290        # This loop replicates that behavior.
 291        for my $path (keys %symlink) {
 292                my $ok;
 293                if (defined($symlink{$path}{left})) {
 294                        $ok = write_to_file("$ldir/$path",
 295                                        $symlink{$path}{left});
 296                }
 297                if (defined($symlink{$path}{right})) {
 298                        $ok = write_to_file("$rdir/$path",
 299                                        $symlink{$path}{right});
 300                }
 301                exit_cleanup($tmpdir, 1) if not $ok;
 302        }
 303
 304        return ($ldir, $rdir, $tmpdir, @working_tree);
 305}
 306
 307sub write_to_file
 308{
 309        my $path = shift;
 310        my $value = shift;
 311
 312        # Make sure the path to the file exists
 313        my $dir = dirname($path);
 314        unless (-d "$dir") {
 315                mkpath("$dir") or return 0;
 316        }
 317
 318        # If the file already exists in that location, delete it.  This
 319        # is required in the case of symbolic links.
 320        unlink($path);
 321
 322        open(my $fh, '>', $path) or return 0;
 323        print($fh $value);
 324        close($fh);
 325
 326        return 1;
 327}
 328
 329sub main
 330{
 331        # parse command-line options. all unrecognized options and arguments
 332        # are passed through to the 'git diff' command.
 333        my %opts = (
 334                difftool_cmd => undef,
 335                dirdiff => undef,
 336                extcmd => undef,
 337                gui => undef,
 338                help => undef,
 339                prompt => undef,
 340                symlinks => $^O ne 'cygwin' &&
 341                                $^O ne 'MSWin32' && $^O ne 'msys',
 342                tool_help => undef,
 343                trust_exit_code => undef,
 344        );
 345        GetOptions('g|gui!' => \$opts{gui},
 346                'd|dir-diff' => \$opts{dirdiff},
 347                'h' => \$opts{help},
 348                'prompt!' => \$opts{prompt},
 349                'y' => sub { $opts{prompt} = 0; },
 350                'symlinks' => \$opts{symlinks},
 351                'no-symlinks' => sub { $opts{symlinks} = 0; },
 352                't|tool:s' => \$opts{difftool_cmd},
 353                'tool-help' => \$opts{tool_help},
 354                'trust-exit-code' => \$opts{trust_exit_code},
 355                'no-trust-exit-code' => sub { $opts{trust_exit_code} = 0; },
 356                'x|extcmd:s' => \$opts{extcmd});
 357
 358        if (defined($opts{help})) {
 359                usage(0);
 360        }
 361        if (defined($opts{tool_help})) {
 362                print_tool_help();
 363        }
 364        if (defined($opts{difftool_cmd})) {
 365                if (length($opts{difftool_cmd}) > 0) {
 366                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 367                } else {
 368                        print "No <tool> given for --tool=<tool>\n";
 369                        usage(1);
 370                }
 371        }
 372        if (defined($opts{extcmd})) {
 373                if (length($opts{extcmd}) > 0) {
 374                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 375                } else {
 376                        print "No <cmd> given for --extcmd=<cmd>\n";
 377                        usage(1);
 378                }
 379        }
 380        if ($opts{gui}) {
 381                my $guitool = Git::config('diff.guitool');
 382                if (defined($guitool) && length($guitool) > 0) {
 383                        $ENV{GIT_DIFF_TOOL} = $guitool;
 384                }
 385        }
 386
 387        if (!defined $opts{trust_exit_code}) {
 388                $opts{trust_exit_code} = Git::config_bool('difftool.trustExitCode');
 389        }
 390        if ($opts{trust_exit_code}) {
 391                $ENV{GIT_DIFFTOOL_TRUST_EXIT_CODE} = 'true';
 392        } else {
 393                $ENV{GIT_DIFFTOOL_TRUST_EXIT_CODE} = 'false';
 394        }
 395
 396        # In directory diff mode, 'git-difftool--helper' is called once
 397        # to compare the a/b directories.  In file diff mode, 'git diff'
 398        # will invoke a separate instance of 'git-difftool--helper' for
 399        # each file that changed.
 400        if (defined($opts{dirdiff})) {
 401                dir_diff($opts{extcmd}, $opts{symlinks});
 402        } else {
 403                file_diff($opts{prompt});
 404        }
 405}
 406
 407sub dir_diff
 408{
 409        my ($extcmd, $symlinks) = @_;
 410        my $rc;
 411        my $error = 0;
 412        my $repo = Git->repository();
 413        my $workdir = find_worktree();
 414        my ($a, $b, $tmpdir, @worktree) =
 415                setup_dir_diff($repo, $workdir, $symlinks);
 416
 417        if (defined($extcmd)) {
 418                $rc = system($extcmd, $a, $b);
 419        } else {
 420                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 421                $rc = system('git', 'difftool--helper', $a, $b);
 422        }
 423        # If the diff including working copy files and those
 424        # files were modified during the diff, then the changes
 425        # should be copied back to the working tree.
 426        # Do not copy back files when symlinks are used and the
 427        # external tool did not replace the original link with a file.
 428        #
 429        # These hashes are loaded lazily since they aren't needed
 430        # in the common case of --symlinks and the difftool updating
 431        # files through the symlink.
 432        my %wt_modified;
 433        my %tmp_modified;
 434        my $indices_loaded = 0;
 435
 436        for my $file (@worktree) {
 437                next if $symlinks && -l "$b/$file";
 438                next if ! -f "$b/$file";
 439
 440                if (!$indices_loaded) {
 441                        %wt_modified = changed_files($repo->repo_path(),
 442                                "$tmpdir/wtindex", "$workdir");
 443                        %tmp_modified = changed_files($repo->repo_path(),
 444                                "$tmpdir/wtindex", "$b");
 445                        $indices_loaded = 1;
 446                }
 447
 448                if (exists $wt_modified{$file} and exists $tmp_modified{$file}) {
 449                        my $errmsg = "warning: Both files modified: ";
 450                        $errmsg .= "'$workdir/$file' and '$b/$file'.\n";
 451                        $errmsg .= "warning: Working tree file has been left.\n";
 452                        $errmsg .= "warning:\n";
 453                        warn $errmsg;
 454                        $error = 1;
 455                } elsif (exists $tmp_modified{$file}) {
 456                        my $mode = stat("$b/$file")->mode;
 457                        copy("$b/$file", "$workdir/$file") or
 458                        exit_cleanup($tmpdir, 1);
 459
 460                        chmod($mode, "$workdir/$file") or
 461                        exit_cleanup($tmpdir, 1);
 462                }
 463        }
 464        if ($error) {
 465                warn "warning: Temporary files exist in '$tmpdir'.\n";
 466                warn "warning: You may want to cleanup or recover these.\n";
 467                exit(1);
 468        } else {
 469                exit_cleanup($tmpdir, $rc);
 470        }
 471}
 472
 473sub file_diff
 474{
 475        my ($prompt) = @_;
 476
 477        if (defined($prompt)) {
 478                if ($prompt) {
 479                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 480                } else {
 481                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 482                }
 483        }
 484
 485        $ENV{GIT_PAGER} = '';
 486        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 487
 488        # ActiveState Perl for Win32 does not implement POSIX semantics of
 489        # exec* system call. It just spawns the given executable and finishes
 490        # the starting program, exiting with code 0.
 491        # system will at least catch the errors returned by git diff,
 492        # allowing the caller of git difftool better handling of failures.
 493        my $rc = system('git', 'diff', @ARGV);
 494        exit($rc | ($rc >> 8));
 495}
 496
 497main();