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