Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit Merge branch 'jt/fetch-no-redundant-tag-fetch-map' into maint (8ee6fc9)
   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 | ($status >> 8));
  58}
  59
  60sub use_wt_file
  61{
  62        my ($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, $wt_sha1);
  72}
  73
  74sub changed_files
  75{
  76        my ($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 { $_ => 1 } @files;
  99}
 100
 101sub setup_dir_diff
 102{
 103        my ($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[$i] =~ /^::/) {
 131                        warn << 'EOF';
 132Combined diff formats ('-c' and '--cc') are not supported in
 133directory diff mode ('-d' and '--dir-diff').
 134EOF
 135                        exit(1);
 136                }
 137
 138                my ($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
 288sub 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
 310sub 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
 388sub 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, $rc);
 452        }
 453}
 454
 455sub file_diff
 456{
 457        my ($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
 479main();