git-difftool.perl

   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
  13 use 5.008;
  14 use strict;
  15 use warnings;
  16 use Error qw(:try);
  17 use File::Basename qw(dirname);
  18 use File::Copy;
  19 use File::Find;
  20 use File::stat;
  21 use File::Path qw(mkpath rmtree);
  22 use File::Temp qw(tempdir);
  23 use Getopt::Long qw(:config pass_through);
  24 use Git;
  25 use Git::I18N;
  26
  27 sub usage
  28 {
  29         my $exitcode = shift;
  30         print << 'USAGE';
  31 usage: git difftool [-t|--tool=<tool>] [--tool-help]
  32                     [-x|--extcmd=<cmd>]
  33                     [-g|--gui] [--no-gui]
  34                     [--prompt] [-y|--no-prompt]
  35                     [-d|--dir-diff]
  36                     ['git diff' options]
  37 USAGE
  38         exit($exitcode);
  39 }
  40
  41 sub print_tool_help
  42 {
  43         # See the comment at the bottom of file_diff() for the reason behind
  44         # using system() followed by exit() instead of exec().
  45         my $rc = system(qw(git mergetool --tool-help=diff));
  46         exit($rc | ($rc >> 8));
  47 }
  48
  49 sub exit_cleanup
  50 {
  51         my ($tmpdir, $status) = @_;
  52         my $errno = $!;
  53         rmtree($tmpdir);
  54         if ($status and $errno) {
  55                 my ($package, $file, $line) = caller();
  56                 warn "$file line $line: $errno\n";
  57         }
  58         exit($status | ($status >> 8));
  59 }
  60
  61 sub use_wt_file
  62 {
  63         my ($workdir, $file, $sha1) = @_;
  64         my $null_sha1 = '0' x 40;
  65
  66         if (-l "$workdir/$file" || ! -e _) {
  67                 return (0, $null_sha1);
  68         }
  69
  70         my $wt_sha1 = Git::command_oneline('hash-object', "$workdir/$file");
  71         my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
  72         return ($use, $wt_sha1);
  73 }
  74
  75 sub changed_files
  76 {
  77         my ($repo_path, $index, $worktree) = @_;
  78         $ENV{GIT_INDEX_FILE} = $index;
  79
  80         my @gitargs = ('--git-dir', $repo_path, '--work-tree', $worktree);
  81         my @refreshargs = (
  82                 @gitargs, 'update-index',
  83                 '--really-refresh', '-q', '--unmerged');
  84         try {
  85                 Git::command_oneline(@refreshargs);
  86         } catch Git::Error::Command with {};
  87
  88         my @diffargs = (@gitargs, 'diff-files', '--name-only', '-z');
  89         my $line = Git::command_oneline(@diffargs);
  90         my @files;
  91         if (defined $line) {
  92                 @files = split('\0', $line);
  93         } else {
  94                 @files = ();
  95         }
  96
  97         delete($ENV{GIT_INDEX_FILE});
  98
  99         return map { $_ => 1 } @files;
 100 }
 101
 102 sub setup_dir_diff
 103 {
 104         my ($workdir, $symlinks) = @_;
 105         my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 106         my $diffrtn = Git::command_oneline(@gitargs);
 107         exit(0) unless defined($diffrtn);
 108
 109         # Build index info for left and right sides of the diff
 110         my $submodule_mode = '160000';
 111         my $symlink_mode = '120000';
 112         my $null_mode = '0' x 6;
 113         my $null_sha1 = '0' x 40;
 114         my $lindex = '';
 115         my $rindex = '';
 116         my $wtindex = '';
 117         my %submodule;
 118         my %symlink;
 119         my @working_tree = ();
 120         my %working_tree_dups = ();
 121         my @rawdiff = split('\0', $diffrtn);
 122
 123         my $i = 0;
 124         while ($i < $#rawdiff) {
 125                 if ($rawdiff[$i] =~ /^::/) {
 126                         warn __ <<'EOF';
 127 Combined diff formats ('-c' and '--cc') are not supported in
 128 directory diff mode ('-d' and '--dir-diff').
 129 EOF
 130                         exit(1);
 131                 }
 132
 133                 my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 134                         split(' ', substr($rawdiff[$i], 1));
 135                 my $src_path = $rawdiff[$i + 1];
 136                 my $dst_path;
 137
 138                 if ($status =~ /^[CR]/) {
 139                         $dst_path = $rawdiff[$i + 2];
 140                         $i += 3;
 141                 } else {
 142                         $dst_path = $src_path;
 143                         $i += 2;
 144                 }
 145
 146                 if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 147                         $submodule{$src_path}{left} = $lsha1;
 148                         if ($lsha1 ne $rsha1) {
 149                                 $submodule{$dst_path}{right} = $rsha1;
 150                         } else {
 151                                 $submodule{$dst_path}{right} = "$rsha1-dirty";
 152                         }
 153                         next;
 154                 }
 155
 156                 if ($lmode eq $symlink_mode) {
 157                         $symlink{$src_path}{left} =
 158                                 Git::command_oneline('show', $lsha1);
 159                 }
 160
 161                 if ($rmode eq $symlink_mode) {
 162                         $symlink{$dst_path}{right} =
 163                                 Git::command_oneline('show', $rsha1);
 164                 }
 165
 166                 if ($lmode ne $null_mode and $status !~ /^C/) {
 167                         $lindex .= "$lmode $lsha1\t$src_path\0";
 168                 }
 169
 170                 if ($rmode ne $null_mode) {
 171                         # Avoid duplicate working_tree entries
 172                         if ($working_tree_dups{$dst_path}++) {
 173                                 next;
 174                         }
 175                         my ($use, $wt_sha1) =
 176                                 use_wt_file($workdir, $dst_path, $rsha1);
 177                         if ($use) {
 178                                 push @working_tree, $dst_path;
 179                                 $wtindex .= "$rmode $wt_sha1\t$dst_path\0";
 180                         } else {
 181                                 $rindex .= "$rmode $rsha1\t$dst_path\0";
 182                         }
 183                 }
 184         }
 185
 186         # Setup temp directories
 187         my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
 188         my $ldir = "$tmpdir/left";
 189         my $rdir = "$tmpdir/right";
 190         mkpath($ldir) or exit_cleanup($tmpdir, 1);
 191         mkpath($rdir) or exit_cleanup($tmpdir, 1);
 192
 193         # Populate the left and right directories based on each index file
 194         my ($inpipe, $ctx);
 195         $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 196         ($inpipe, $ctx) =
 197                 Git::command_input_pipe('update-index', '-z', '--index-info');
 198         print($inpipe $lindex);
 199         Git::command_close_pipe($inpipe, $ctx);
 200
 201         my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 202         exit_cleanup($tmpdir, $rc) if $rc != 0;
 203
 204         $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 205         ($inpipe, $ctx) =
 206                 Git::command_input_pipe('update-index', '-z', '--index-info');
 207         print($inpipe $rindex);
 208         Git::command_close_pipe($inpipe, $ctx);
 209
 210         $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 211         exit_cleanup($tmpdir, $rc) if $rc != 0;
 212
 213         $ENV{GIT_INDEX_FILE} = "$tmpdir/wtindex";
 214         ($inpipe, $ctx) =
 215                 Git::command_input_pipe('update-index', '--info-only', '-z', '--index-info');
 216         print($inpipe $wtindex);
 217         Git::command_close_pipe($inpipe, $ctx);
 218
 219         # If $GIT_DIR was explicitly set just for the update/checkout
 220         # commands, then it should be unset before continuing.
 221         delete($ENV{GIT_INDEX_FILE});
 222
 223         # Changes in the working tree need special treatment since they are
 224         # not part of the index. Remove any trailing slash from $workdir
 225         # before starting to avoid double slashes in symlink targets.
 226         $workdir =~ s|/$||;
 227         for my $file (@working_tree) {
 228                 my $dir = dirname($file);
 229                 unless (-d "$rdir/$dir") {
 230                         mkpath("$rdir/$dir") or
 231                         exit_cleanup($tmpdir, 1);
 232                 }
 233                 if ($symlinks) {
 234                         symlink("$workdir/$file", "$rdir/$file") or
 235                         exit_cleanup($tmpdir, 1);
 236                 } else {
 237                         copy("$workdir/$file", "$rdir/$file") or
 238                         exit_cleanup($tmpdir, 1);
 239
 240                         my $mode = stat("$workdir/$file")->mode;
 241                         chmod($mode, "$rdir/$file") or
 242                         exit_cleanup($tmpdir, 1);
 243                 }
 244         }
 245
 246         # Changes to submodules require special treatment. This loop writes a
 247         # temporary file to both the left and right directories to show the
 248         # change in the recorded SHA1 for the submodule.
 249         for my $path (keys %submodule) {
 250                 my $ok = 0;
 251                 if (defined($submodule{$path}{left})) {
 252                         $ok = write_to_file("$ldir/$path",
 253                                 "Subproject commit $submodule{$path}{left}");
 254                 }
 255                 if (defined($submodule{$path}{right})) {
 256                         $ok = write_to_file("$rdir/$path",
 257                                 "Subproject commit $submodule{$path}{right}");
 258                 }
 259                 exit_cleanup($tmpdir, 1) if not $ok;
 260         }
 261
 262         # Symbolic links require special treatment. The standard "git diff"
 263         # shows only the link itself, not the contents of the link target.
 264         # This loop replicates that behavior.
 265         for my $path (keys %symlink) {
 266                 my $ok = 0;
 267                 if (defined($symlink{$path}{left})) {
 268                         $ok = write_to_file("$ldir/$path",
 269                                         $symlink{$path}{left});
 270                 }
 271                 if (defined($symlink{$path}{right})) {
 272                         $ok = write_to_file("$rdir/$path",
 273                                         $symlink{$path}{right});
 274                 }
 275                 exit_cleanup($tmpdir, 1) if not $ok;
 276         }
 277
 278         return ($ldir, $rdir, $tmpdir, @working_tree);
 279 }
 280
 281 sub write_to_file
 282 {
 283         my $path = shift;
 284         my $value = shift;
 285
 286         # Make sure the path to the file exists
 287         my $dir = dirname($path);
 288         unless (-d "$dir") {
 289                 mkpath("$dir") or return 0;
 290         }
 291
 292         # If the file already exists in that location, delete it.  This
 293         # is required in the case of symbolic links.
 294         unlink($path);
 295
 296         open(my $fh, '>', $path) or return 0;
 297         print($fh $value);
 298         close($fh);
 299
 300         return 1;
 301 }
 302
 303 sub main
 304 {
 305         # parse command-line options. all unrecognized options and arguments
 306         # are passed through to the 'git diff' command.
 307         my %opts = (
 308                 difftool_cmd => undef,
 309                 dirdiff => undef,
 310                 extcmd => undef,
 311                 gui => undef,
 312                 help => undef,
 313                 prompt => undef,
 314                 symlinks => $^O ne 'cygwin' &&
 315                                 $^O ne 'MSWin32' && $^O ne 'msys',
 316                 tool_help => undef,
 317                 trust_exit_code => undef,
 318         );
 319         GetOptions('g|gui!' => \$opts{gui},
 320                 'd|dir-diff' => \$opts{dirdiff},
 321                 'h' => \$opts{help},
 322                 'prompt!' => \$opts{prompt},
 323                 'y' => sub { $opts{prompt} = 0; },
 324                 'symlinks' => \$opts{symlinks},
 325                 'no-symlinks' => sub { $opts{symlinks} = 0; },
 326                 't|tool:s' => \$opts{difftool_cmd},
 327                 'tool-help' => \$opts{tool_help},
 328                 'trust-exit-code' => \$opts{trust_exit_code},
 329                 'no-trust-exit-code' => sub { $opts{trust_exit_code} = 0; },
 330                 'x|extcmd:s' => \$opts{extcmd});
 331
 332         if (defined($opts{help})) {
 333                 usage(0);
 334         }
 335         if (defined($opts{tool_help})) {
 336                 print_tool_help();
 337         }
 338         if (defined($opts{difftool_cmd})) {
 339                 if (length($opts{difftool_cmd}) > 0) {
 340                         $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 341                 } else {
 342                         print __("No <tool> given for --tool=<tool>\n");
 343                         usage(1);
 344                 }
 345         }
 346         if (defined($opts{extcmd})) {
 347                 if (length($opts{extcmd}) > 0) {
 348                         $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 349                 } else {
 350                         print __("No <cmd> given for --extcmd=<cmd>\n");
 351                         usage(1);
 352                 }
 353         }
 354         if ($opts{gui}) {
 355                 my $guitool = Git::config('diff.guitool');
 356                 if (defined($guitool) && length($guitool) > 0) {
 357                         $ENV{GIT_DIFF_TOOL} = $guitool;
 358                 }
 359         }
 360
 361         if (!defined $opts{trust_exit_code}) {
 362                 $opts{trust_exit_code} = Git::config_bool('difftool.trustExitCode');
 363         }
 364         if ($opts{trust_exit_code}) {
 365                 $ENV{GIT_DIFFTOOL_TRUST_EXIT_CODE} = 'true';
 366         } else {
 367                 $ENV{GIT_DIFFTOOL_TRUST_EXIT_CODE} = 'false';
 368         }
 369
 370         # In directory diff mode, 'git-difftool--helper' is called once
 371         # to compare the a/b directories.  In file diff mode, 'git diff'
 372         # will invoke a separate instance of 'git-difftool--helper' for
 373         # each file that changed.
 374         if (defined($opts{dirdiff})) {
 375                 dir_diff($opts{extcmd}, $opts{symlinks});
 376         } else {
 377                 file_diff($opts{prompt});
 378         }
 379 }
 380
 381 sub dir_diff
 382 {
 383         my ($extcmd, $symlinks) = @_;
 384         my $rc;
 385         my $error = 0;
 386         my $repo = Git->repository();
 387         my $repo_path = $repo->repo_path();
 388         my $workdir = $repo->wc_path();
 389         my ($a, $b, $tmpdir, @worktree) = setup_dir_diff($workdir, $symlinks);
 390
 391         if (defined($extcmd)) {
 392                 $rc = system($extcmd, $a, $b);
 393         } else {
 394                 $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 395                 $rc = system('git', 'difftool--helper', $a, $b);
 396         }
 397         # If the diff including working copy files and those
 398         # files were modified during the diff, then the changes
 399         # should be copied back to the working tree.
 400         # Do not copy back files when symlinks are used and the
 401         # external tool did not replace the original link with a file.
 402         #
 403         # These hashes are loaded lazily since they aren't needed
 404         # in the common case of --symlinks and the difftool updating
 405         # files through the symlink.
 406         my %wt_modified;
 407         my %tmp_modified;
 408         my $indices_loaded = 0;
 409
 410         for my $file (@worktree) {
 411                 next if $symlinks && -l "$b/$file";
 412                 next if ! -f "$b/$file";
 413
 414                 if (!$indices_loaded) {
 415                         %wt_modified = changed_files(
 416                                 $repo_path, "$tmpdir/wtindex", $workdir);
 417                         %tmp_modified = changed_files(
 418                                 $repo_path, "$tmpdir/wtindex", $b);
 419                         $indices_loaded = 1;
 420                 }
 421
 422                 if (exists $wt_modified{$file} and exists $tmp_modified{$file}) {
 423                         warn sprintf(__(
 424                                 "warning: Both files modified:\n" .
 425                                 "'%s/%s' and '%s/%s'.\n" .
 426                                 "warning: Working tree file has been left.\n" .
 427                                 "warning:\n"), $workdir, $file, $b, $file);
 428                         $error = 1;
 429                 } elsif (exists $tmp_modified{$file}) {
 430                         my $mode = stat("$b/$file")->mode;
 431                         copy("$b/$file", "$workdir/$file") or
 432                         exit_cleanup($tmpdir, 1);
 433
 434                         chmod($mode, "$workdir/$file") or
 435                         exit_cleanup($tmpdir, 1);
 436                 }
 437         }
 438         if ($error) {
 439                 warn sprintf(__(
 440                         "warning: Temporary files exist in '%s'.\n" .
 441                         "warning: You may want to cleanup or recover these.\n"), $tmpdir);
 442                 exit(1);
 443         } else {
 444                 exit_cleanup($tmpdir, $rc);
 445         }
 446 }
 447
 448 sub file_diff
 449 {
 450         my ($prompt) = @_;
 451
 452         if (defined($prompt)) {
 453                 if ($prompt) {
 454                         $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 455                 } else {
 456                         $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 457                 }
 458         }
 459
 460         $ENV{GIT_PAGER} = '';
 461         $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 462
 463         # ActiveState Perl for Win32 does not implement POSIX semantics of
 464         # exec* system call. It just spawns the given executable and finishes
 465         # the starting program, exiting with code 0.
 466         # system will at least catch the errors returned by git diff,
 467         # allowing the caller of git difftool better handling of failures.
 468         my $rc = system('git', 'diff', @ARGV);
 469         exit($rc | ($rc >> 8));
 470 }
 471
 472 main();