Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit Update draft release notes to 1.8.2 (2f19ada)
   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 File::Basename qw(dirname);
  17use File::Copy;
  18use File::Compare;
  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 find_worktree
  41{
  42        my ($repo) = @_;
  43
  44        # Git->repository->wc_path() does not honor changes to the working
  45        # tree location made by $ENV{GIT_WORK_TREE} or the 'core.worktree'
  46        # config variable.
  47        my $worktree;
  48        my $env_worktree = $ENV{GIT_WORK_TREE};
  49        my $core_worktree = Git::config('core.worktree');
  50
  51        if (defined($env_worktree) and (length($env_worktree) > 0)) {
  52                $worktree = $env_worktree;
  53        } elsif (defined($core_worktree) and (length($core_worktree) > 0)) {
  54                $worktree = $core_worktree;
  55        } else {
  56                $worktree = $repo->wc_path();
  57        }
  58
  59        return $worktree;
  60}
  61
  62sub filter_tool_scripts
  63{
  64        my ($tools) = @_;
  65        if (-d $_) {
  66                if ($_ ne ".") {
  67                        # Ignore files in subdirectories
  68                        $File::Find::prune = 1;
  69                }
  70        } else {
  71                if ((-f $_) && ($_ ne "defaults")) {
  72                        push(@$tools, $_);
  73                }
  74        }
  75}
  76
  77sub print_tool_help
  78{
  79        my ($cmd, @found, @notfound, @tools);
  80        my $gitpath = Git::exec_path();
  81
  82        find(sub { filter_tool_scripts(\@tools) }, "$gitpath/mergetools");
  83
  84        foreach my $tool (@tools) {
  85                $cmd  = "TOOL_MODE=diff";
  86                $cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
  87                $cmd .= " && get_merge_tool_path $tool >/dev/null 2>&1";
  88                $cmd .= " && can_diff >/dev/null 2>&1";
  89                if (system('sh', '-c', $cmd) == 0) {
  90                        push(@found, $tool);
  91                } else {
  92                        push(@notfound, $tool);
  93                }
  94        }
  95
  96        print << 'EOF';
  97'git difftool --tool=<tool>' may be set to one of the following:
  98EOF
  99        print "\t$_\n" for (sort(@found));
 100
 101        print << 'EOF';
 102
 103The following tools are valid, but not currently available:
 104EOF
 105        print "\t$_\n" for (sort(@notfound));
 106
 107        print << 'EOF';
 108
 109NOTE: Some of the tools listed above only work in a windowed
 110environment. If run in a terminal-only session, they will fail.
 111EOF
 112        exit(0);
 113}
 114
 115sub exit_cleanup
 116{
 117        my ($tmpdir, $status) = @_;
 118        my $errno = $!;
 119        rmtree($tmpdir);
 120        if ($status and $errno) {
 121                my ($package, $file, $line) = caller();
 122                warn "$file line $line: $errno\n";
 123        }
 124        exit($status | ($status >> 8));
 125}
 126
 127sub setup_dir_diff
 128{
 129        my ($repo, $workdir, $symlinks) = @_;
 130
 131        # Run the diff; exit immediately if no diff found
 132        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 133        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 134        # by Git->repository->command*.
 135        my $repo_path = $repo->repo_path();
 136        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
 137        my $diffrepo = Git->repository(%repo_args);
 138
 139        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 140        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 141        exit(0) unless defined($diffrtn);
 142
 143        # Build index info for left and right sides of the diff
 144        my $submodule_mode = '160000';
 145        my $symlink_mode = '120000';
 146        my $null_mode = '0' x 6;
 147        my $null_sha1 = '0' x 40;
 148        my $lindex = '';
 149        my $rindex = '';
 150        my %submodule;
 151        my %symlink;
 152        my @working_tree = ();
 153        my @rawdiff = split('\0', $diffrtn);
 154
 155        my $i = 0;
 156        while ($i < $#rawdiff) {
 157                if ($rawdiff[$i] =~ /^::/) {
 158                        warn << 'EOF';
 159Combined diff formats ('-c' and '--cc') are not supported in
 160directory diff mode ('-d' and '--dir-diff').
 161EOF
 162                        exit(1);
 163                }
 164
 165                my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 166                        split(' ', substr($rawdiff[$i], 1));
 167                my $src_path = $rawdiff[$i + 1];
 168                my $dst_path;
 169
 170                if ($status =~ /^[CR]/) {
 171                        $dst_path = $rawdiff[$i + 2];
 172                        $i += 3;
 173                } else {
 174                        $dst_path = $src_path;
 175                        $i += 2;
 176                }
 177
 178                if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 179                        $submodule{$src_path}{left} = $lsha1;
 180                        if ($lsha1 ne $rsha1) {
 181                                $submodule{$dst_path}{right} = $rsha1;
 182                        } else {
 183                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 184                        }
 185                        next;
 186                }
 187
 188                if ($lmode eq $symlink_mode) {
 189                        $symlink{$src_path}{left} =
 190                                $diffrepo->command_oneline('show', "$lsha1");
 191                }
 192
 193                if ($rmode eq $symlink_mode) {
 194                        $symlink{$dst_path}{right} =
 195                                $diffrepo->command_oneline('show', "$rsha1");
 196                }
 197
 198                if ($lmode ne $null_mode and $status !~ /^C/) {
 199                        $lindex .= "$lmode $lsha1\t$src_path\0";
 200                }
 201
 202                if ($rmode ne $null_mode) {
 203                        if ($rsha1 ne $null_sha1) {
 204                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 205                        } else {
 206                                push(@working_tree, $dst_path);
 207                        }
 208                }
 209        }
 210
 211        # Setup temp directories
 212        my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
 213        my $ldir = "$tmpdir/left";
 214        my $rdir = "$tmpdir/right";
 215        mkpath($ldir) or exit_cleanup($tmpdir, 1);
 216        mkpath($rdir) or exit_cleanup($tmpdir, 1);
 217
 218        # If $GIT_DIR is not set prior to calling 'git update-index' and
 219        # 'git checkout-index', then those commands will fail if difftool
 220        # is called from a directory other than the repo root.
 221        my $must_unset_git_dir = 0;
 222        if (not defined($ENV{GIT_DIR})) {
 223                $must_unset_git_dir = 1;
 224                $ENV{GIT_DIR} = $repo_path;
 225        }
 226
 227        # Populate the left and right directories based on each index file
 228        my ($inpipe, $ctx);
 229        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 230        ($inpipe, $ctx) =
 231                $repo->command_input_pipe(qw(update-index -z --index-info));
 232        print($inpipe $lindex);
 233        $repo->command_close_pipe($inpipe, $ctx);
 234
 235        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 236        exit_cleanup($tmpdir, $rc) if $rc != 0;
 237
 238        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 239        ($inpipe, $ctx) =
 240                $repo->command_input_pipe(qw(update-index -z --index-info));
 241        print($inpipe $rindex);
 242        $repo->command_close_pipe($inpipe, $ctx);
 243
 244        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 245        exit_cleanup($tmpdir, $rc) if $rc != 0;
 246
 247        # If $GIT_DIR was explicitly set just for the update/checkout
 248        # commands, then it should be unset before continuing.
 249        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 250        delete($ENV{GIT_INDEX_FILE});
 251
 252        # Changes in the working tree need special treatment since they are
 253        # not part of the index
 254        for my $file (@working_tree) {
 255                my $dir = dirname($file);
 256                unless (-d "$rdir/$dir") {
 257                        mkpath("$rdir/$dir") or
 258                        exit_cleanup($tmpdir, 1);
 259                }
 260                if ($symlinks) {
 261                        symlink("$workdir/$file", "$rdir/$file") or
 262                        exit_cleanup($tmpdir, 1);
 263                } else {
 264                        copy("$workdir/$file", "$rdir/$file") or
 265                        exit_cleanup($tmpdir, 1);
 266
 267                        my $mode = stat("$workdir/$file")->mode;
 268                        chmod($mode, "$rdir/$file") or
 269                        exit_cleanup($tmpdir, 1);
 270                }
 271        }
 272
 273        # Changes to submodules require special treatment. This loop writes a
 274        # temporary file to both the left and right directories to show the
 275        # change in the recorded SHA1 for the submodule.
 276        for my $path (keys %submodule) {
 277                my $ok;
 278                if (defined($submodule{$path}{left})) {
 279                        $ok = write_to_file("$ldir/$path",
 280                                "Subproject commit $submodule{$path}{left}");
 281                }
 282                if (defined($submodule{$path}{right})) {
 283                        $ok = write_to_file("$rdir/$path",
 284                                "Subproject commit $submodule{$path}{right}");
 285                }
 286                exit_cleanup($tmpdir, 1) if not $ok;
 287        }
 288
 289        # Symbolic links require special treatment. The standard "git diff"
 290        # shows only the link itself, not the contents of the link target.
 291        # This loop replicates that behavior.
 292        for my $path (keys %symlink) {
 293                my $ok;
 294                if (defined($symlink{$path}{left})) {
 295                        $ok = write_to_file("$ldir/$path",
 296                                        $symlink{$path}{left});
 297                }
 298                if (defined($symlink{$path}{right})) {
 299                        $ok = write_to_file("$rdir/$path",
 300                                        $symlink{$path}{right});
 301                }
 302                exit_cleanup($tmpdir, 1) if not $ok;
 303        }
 304
 305        return ($ldir, $rdir, $tmpdir, @working_tree);
 306}
 307
 308sub write_to_file
 309{
 310        my $path = shift;
 311        my $value = shift;
 312
 313        # Make sure the path to the file exists
 314        my $dir = dirname($path);
 315        unless (-d "$dir") {
 316                mkpath("$dir") or return 0;
 317        }
 318
 319        # If the file already exists in that location, delete it.  This
 320        # is required in the case of symbolic links.
 321        unlink($path);
 322
 323        open(my $fh, '>', $path) or return 0;
 324        print($fh $value);
 325        close($fh);
 326
 327        return 1;
 328}
 329
 330sub main
 331{
 332        # parse command-line options. all unrecognized options and arguments
 333        # are passed through to the 'git diff' command.
 334        my %opts = (
 335                difftool_cmd => undef,
 336                dirdiff => undef,
 337                extcmd => undef,
 338                gui => undef,
 339                help => undef,
 340                prompt => undef,
 341                symlinks => $^O ne 'cygwin' &&
 342                                $^O ne 'MSWin32' && $^O ne 'msys',
 343                tool_help => undef,
 344        );
 345        GetOptions('g|gui!' => \$opts{gui},
 346                'd|dir-diff' => \$opts{dirdiff},
 347                'h' => \$opts{help},
 348                'prompt!' => \$opts{prompt},
 349                'y' => sub { $opts{prompt} = 0; },
 350                'symlinks' => \$opts{symlinks},
 351                'no-symlinks' => sub { $opts{symlinks} = 0; },
 352                't|tool:s' => \$opts{difftool_cmd},
 353                'tool-help' => \$opts{tool_help},
 354                'x|extcmd:s' => \$opts{extcmd});
 355
 356        if (defined($opts{help})) {
 357                usage(0);
 358        }
 359        if (defined($opts{tool_help})) {
 360                print_tool_help();
 361        }
 362        if (defined($opts{difftool_cmd})) {
 363                if (length($opts{difftool_cmd}) > 0) {
 364                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 365                } else {
 366                        print "No <tool> given for --tool=<tool>\n";
 367                        usage(1);
 368                }
 369        }
 370        if (defined($opts{extcmd})) {
 371                if (length($opts{extcmd}) > 0) {
 372                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 373                } else {
 374                        print "No <cmd> given for --extcmd=<cmd>\n";
 375                        usage(1);
 376                }
 377        }
 378        if ($opts{gui}) {
 379                my $guitool = Git::config('diff.guitool');
 380                if (length($guitool) > 0) {
 381                        $ENV{GIT_DIFF_TOOL} = $guitool;
 382                }
 383        }
 384
 385        # In directory diff mode, 'git-difftool--helper' is called once
 386        # to compare the a/b directories.  In file diff mode, 'git diff'
 387        # will invoke a separate instance of 'git-difftool--helper' for
 388        # each file that changed.
 389        if (defined($opts{dirdiff})) {
 390                dir_diff($opts{extcmd}, $opts{symlinks});
 391        } else {
 392                file_diff($opts{prompt});
 393        }
 394}
 395
 396sub dir_diff
 397{
 398        my ($extcmd, $symlinks) = @_;
 399        my $rc;
 400        my $error = 0;
 401        my $repo = Git->repository();
 402        my $workdir = find_worktree($repo);
 403        my ($a, $b, $tmpdir, @worktree) =
 404                setup_dir_diff($repo, $workdir, $symlinks);
 405
 406        if (defined($extcmd)) {
 407                $rc = system($extcmd, $a, $b);
 408        } else {
 409                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 410                $rc = system('git', 'difftool--helper', $a, $b);
 411        }
 412        # If the diff including working copy files and those
 413        # files were modified during the diff, then the changes
 414        # should be copied back to the working tree.
 415        # Do not copy back files when symlinks are used and the
 416        # external tool did not replace the original link with a file.
 417        for my $file (@worktree) {
 418                next if $symlinks && -l "$b/$file";
 419                next if ! -f "$b/$file";
 420
 421                my $diff = compare("$b/$file", "$workdir/$file");
 422                if ($diff == 0) {
 423                        next;
 424                } elsif ($diff == -1) {
 425                        my $errmsg = "warning: Could not compare ";
 426                        $errmsg += "'$b/$file' with '$workdir/$file'\n";
 427                        warn $errmsg;
 428                        $error = 1;
 429                } elsif ($diff == 1) {
 430                        my $mode = stat("$b/$file")->mode;
 431                        copy("$b/$file", "$workdir/$file") or
 432                        exit_cleanup($tmpdir, 1);
 433
 434                        chmod($mode, "$workdir/$file") or
 435                        exit_cleanup($tmpdir, 1);
 436                }
 437        }
 438        if ($error) {
 439                warn "warning: Temporary files exist in '$tmpdir'.\n";
 440                warn "warning: You may want to cleanup or recover these.\n";
 441                exit(1);
 442        } else {
 443                exit_cleanup($tmpdir, $rc);
 444        }
 445}
 446
 447sub file_diff
 448{
 449        my ($prompt) = @_;
 450
 451        if (defined($prompt)) {
 452                if ($prompt) {
 453                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 454                } else {
 455                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 456                }
 457        }
 458
 459        $ENV{GIT_PAGER} = '';
 460        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 461
 462        # ActiveState Perl for Win32 does not implement POSIX semantics of
 463        # exec* system call. It just spawns the given executable and finishes
 464        # the starting program, exiting with code 0.
 465        # system will at least catch the errors returned by git diff,
 466        # allowing the caller of git difftool better handling of failures.
 467        my $rc = system('git', 'diff', @ARGV);
 468        exit($rc | ($rc >> 8));
 469}
 470
 471main();