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