Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit trailer: streamline trailer item create and add (63ab3f3)
   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 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 | ($rc >> 8));
  46}
  47
  48sub exit_cleanup
  49{
  50        my ($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 | ($status >> 8));
  58}
  59
  60sub use_wt_file
  61{
  62        my ($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, $wt_sha1);
  72}
  73
  74sub changed_files
  75{
  76        my ($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 { $_ => 1 } @files;
  99}
 100
 101sub setup_dir_diff
 102{
 103        my ($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[$i] =~ /^::/) {
 125                        warn << 'EOF';
 126Combined diff formats ('-c' and '--cc') are not supported in
 127directory diff mode ('-d' and '--dir-diff').
 128EOF
 129                        exit(1);
 130                }
 131
 132                my ($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
 280sub 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
 302sub 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
 380sub 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, $rc);
 443        }
 444}
 445
 446sub file_diff
 447{
 448        my ($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
 470main();