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