Andrew's git - gitweb.git/blob

   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 print_tool_help
  63{
  64        my $cmd = 'TOOL_MODE=diff';
  65        $cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
  66        $cmd .= ' && show_tool_help';
  67
  68        # See the comment at the bottom of file_diff() for the reason behind
  69        # using system() followed by exit() instead of exec().
  70        my $rc = system('sh', '-c', $cmd);
  71        exit($rc | ($rc >> 8));
  72}
  73
  74sub exit_cleanup
  75{
  76        my ($tmpdir, $status) = @_;
  77        my $errno = $!;
  78        rmtree($tmpdir);
  79        if ($status and $errno) {
  80                my ($package, $file, $line) = caller();
  81                warn "$file line $line: $errno\n";
  82        }
  83        exit($status | ($status >> 8));
  84}
  85
  86sub use_wt_file
  87{
  88        my ($repo, $workdir, $file, $sha1, $symlinks) = @_;
  89        my $null_sha1 = '0' x 40;
  90
  91        if ($sha1 eq $null_sha1) {
  92                return 1;
  93        } elsif (not $symlinks) {
  94                return 0;
  95        }
  96
  97        my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
  98        return $sha1 eq $wt_sha1;
  99}
 100
 101sub setup_dir_diff
 102{
 103        my ($repo, $workdir, $symlinks) = @_;
 104
 105        # Run the diff; exit immediately if no diff found
 106        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 107        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 108        # by Git->repository->command*.
 109        my $repo_path = $repo->repo_path();
 110        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
 111        my $diffrepo = Git->repository(%repo_args);
 112
 113        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 114        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 115        exit(0) unless defined($diffrtn);
 116
 117        # Build index info for left and right sides of the diff
 118        my $submodule_mode = '160000';
 119        my $symlink_mode = '120000';
 120        my $null_mode = '0' x 6;
 121        my $null_sha1 = '0' x 40;
 122        my $lindex = '';
 123        my $rindex = '';
 124        my %submodule;
 125        my %symlink;
 126        my @working_tree = ();
 127        my @rawdiff = split('\0', $diffrtn);
 128
 129        my $i = 0;
 130        while ($i < $#rawdiff) {
 131                if ($rawdiff[$i] =~ /^::/) {
 132                        warn << 'EOF';
 133Combined diff formats ('-c' and '--cc') are not supported in
 134directory diff mode ('-d' and '--dir-diff').
 135EOF
 136                        exit(1);
 137                }
 138
 139                my ($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                                $diffrepo->command_oneline('show', "$lsha1");
 165                }
 166
 167                if ($rmode eq $symlink_mode) {
 168                        $symlink{$dst_path}{right} =
 169                                $diffrepo->command_oneline('show', "$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 $null_mode) {
 177                        if (use_wt_file($repo, $workdir, $dst_path, $rsha1, $symlinks)) {
 178                                push(@working_tree, $dst_path);
 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        # If $GIT_DIR is not set prior to calling 'git update-index' and
 193        # 'git checkout-index', then those commands will fail if difftool
 194        # is called from a directory other than the repo root.
 195        my $must_unset_git_dir = 0;
 196        if (not defined($ENV{GIT_DIR})) {
 197                $must_unset_git_dir = 1;
 198                $ENV{GIT_DIR} = $repo_path;
 199        }
 200
 201        # Populate the left and right directories based on each index file
 202        my ($inpipe, $ctx);
 203        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 204        ($inpipe, $ctx) =
 205                $repo->command_input_pipe(qw(update-index -z --index-info));
 206        print($inpipe $lindex);
 207        $repo->command_close_pipe($inpipe, $ctx);
 208
 209        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 210        exit_cleanup($tmpdir, $rc) if $rc != 0;
 211
 212        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 213        ($inpipe, $ctx) =
 214                $repo->command_input_pipe(qw(update-index -z --index-info));
 215        print($inpipe $rindex);
 216        $repo->command_close_pipe($inpipe, $ctx);
 217
 218        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 219        exit_cleanup($tmpdir, $rc) if $rc != 0;
 220
 221        # If $GIT_DIR was explicitly set just for the update/checkout
 222        # commands, then it should be unset before continuing.
 223        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 224        delete($ENV{GIT_INDEX_FILE});
 225
 226        # Changes in the working tree need special treatment since they are
 227        # not part of the index. Remove any trailing slash from $workdir
 228        # before starting to avoid double slashes in symlink targets.
 229        $workdir =~ s|/$||;
 230        for my $file (@working_tree) {
 231                my $dir = dirname($file);
 232                unless (-d "$rdir/$dir") {
 233                        mkpath("$rdir/$dir") or
 234                        exit_cleanup($tmpdir, 1);
 235                }
 236                if ($symlinks) {
 237                        symlink("$workdir/$file", "$rdir/$file") or
 238                        exit_cleanup($tmpdir, 1);
 239                } else {
 240                        copy("$workdir/$file", "$rdir/$file") or
 241                        exit_cleanup($tmpdir, 1);
 242
 243                        my $mode = stat("$workdir/$file")->mode;
 244                        chmod($mode, "$rdir/$file") or
 245                        exit_cleanup($tmpdir, 1);
 246                }
 247        }
 248
 249        # Changes to submodules require special treatment. This loop writes a
 250        # temporary file to both the left and right directories to show the
 251        # change in the recorded SHA1 for the submodule.
 252        for my $path (keys %submodule) {
 253                my $ok;
 254                if (defined($submodule{$path}{left})) {
 255                        $ok = write_to_file("$ldir/$path",
 256                                "Subproject commit $submodule{$path}{left}");
 257                }
 258                if (defined($submodule{$path}{right})) {
 259                        $ok = write_to_file("$rdir/$path",
 260                                "Subproject commit $submodule{$path}{right}");
 261                }
 262                exit_cleanup($tmpdir, 1) if not $ok;
 263        }
 264
 265        # Symbolic links require special treatment. The standard "git diff"
 266        # shows only the link itself, not the contents of the link target.
 267        # This loop replicates that behavior.
 268        for my $path (keys %symlink) {
 269                my $ok;
 270                if (defined($symlink{$path}{left})) {
 271                        $ok = write_to_file("$ldir/$path",
 272                                        $symlink{$path}{left});
 273                }
 274                if (defined($symlink{$path}{right})) {
 275                        $ok = write_to_file("$rdir/$path",
 276                                        $symlink{$path}{right});
 277                }
 278                exit_cleanup($tmpdir, 1) if not $ok;
 279        }
 280
 281        return ($ldir, $rdir, $tmpdir, @working_tree);
 282}
 283
 284sub write_to_file
 285{
 286        my $path = shift;
 287        my $value = shift;
 288
 289        # Make sure the path to the file exists
 290        my $dir = dirname($path);
 291        unless (-d "$dir") {
 292                mkpath("$dir") or return 0;
 293        }
 294
 295        # If the file already exists in that location, delete it.  This
 296        # is required in the case of symbolic links.
 297        unlink($path);
 298
 299        open(my $fh, '>', $path) or return 0;
 300        print($fh $value);
 301        close($fh);
 302
 303        return 1;
 304}
 305
 306sub main
 307{
 308        # parse command-line options. all unrecognized options and arguments
 309        # are passed through to the 'git diff' command.
 310        my %opts = (
 311                difftool_cmd => undef,
 312                dirdiff => undef,
 313                extcmd => undef,
 314                gui => undef,
 315                help => undef,
 316                prompt => undef,
 317                symlinks => $^O ne 'cygwin' &&
 318                                $^O ne 'MSWin32' && $^O ne 'msys',
 319                tool_help => undef,
 320        );
 321        GetOptions('g|gui!' => \$opts{gui},
 322                'd|dir-diff' => \$opts{dirdiff},
 323                'h' => \$opts{help},
 324                'prompt!' => \$opts{prompt},
 325                'y' => sub { $opts{prompt} = 0; },
 326                'symlinks' => \$opts{symlinks},
 327                'no-symlinks' => sub { $opts{symlinks} = 0; },
 328                't|tool:s' => \$opts{difftool_cmd},
 329                'tool-help' => \$opts{tool_help},
 330                'x|extcmd:s' => \$opts{extcmd});
 331
 332        if (defined($opts{help})) {
 333                usage(0);
 334        }
 335        if (defined($opts{tool_help})) {
 336                print_tool_help();
 337        }
 338        if (defined($opts{difftool_cmd})) {
 339                if (length($opts{difftool_cmd}) > 0) {
 340                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 341                } else {
 342                        print "No <tool> given for --tool=<tool>\n";
 343                        usage(1);
 344                }
 345        }
 346        if (defined($opts{extcmd})) {
 347                if (length($opts{extcmd}) > 0) {
 348                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 349                } else {
 350                        print "No <cmd> given for --extcmd=<cmd>\n";
 351                        usage(1);
 352                }
 353        }
 354        if ($opts{gui}) {
 355                my $guitool = Git::config('diff.guitool');
 356                if (defined($guitool) && length($guitool) > 0) {
 357                        $ENV{GIT_DIFF_TOOL} = $guitool;
 358                }
 359        }
 360
 361        # In directory diff mode, 'git-difftool--helper' is called once
 362        # to compare the a/b directories.  In file diff mode, 'git diff'
 363        # will invoke a separate instance of 'git-difftool--helper' for
 364        # each file that changed.
 365        if (defined($opts{dirdiff})) {
 366                dir_diff($opts{extcmd}, $opts{symlinks});
 367        } else {
 368                file_diff($opts{prompt});
 369        }
 370}
 371
 372sub dir_diff
 373{
 374        my ($extcmd, $symlinks) = @_;
 375        my $rc;
 376        my $error = 0;
 377        my $repo = Git->repository();
 378        my $workdir = find_worktree($repo);
 379        my ($a, $b, $tmpdir, @worktree) =
 380                setup_dir_diff($repo, $workdir, $symlinks);
 381
 382        if (defined($extcmd)) {
 383                $rc = system($extcmd, $a, $b);
 384        } else {
 385                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 386                $rc = system('git', 'difftool--helper', $a, $b);
 387        }
 388        # If the diff including working copy files and those
 389        # files were modified during the diff, then the changes
 390        # should be copied back to the working tree.
 391        # Do not copy back files when symlinks are used and the
 392        # external tool did not replace the original link with a file.
 393        for my $file (@worktree) {
 394                next if $symlinks && -l "$b/$file";
 395                next if ! -f "$b/$file";
 396
 397                my $diff = compare("$b/$file", "$workdir/$file");
 398                if ($diff == 0) {
 399                        next;
 400                } elsif ($diff == -1) {
 401                        my $errmsg = "warning: Could not compare ";
 402                        $errmsg += "'$b/$file' with '$workdir/$file'\n";
 403                        warn $errmsg;
 404                        $error = 1;
 405                } elsif ($diff == 1) {
 406                        my $mode = stat("$b/$file")->mode;
 407                        copy("$b/$file", "$workdir/$file") or
 408                        exit_cleanup($tmpdir, 1);
 409
 410                        chmod($mode, "$workdir/$file") or
 411                        exit_cleanup($tmpdir, 1);
 412                }
 413        }
 414        if ($error) {
 415                warn "warning: Temporary files exist in '$tmpdir'.\n";
 416                warn "warning: You may want to cleanup or recover these.\n";
 417                exit(1);
 418        } else {
 419                exit_cleanup($tmpdir, $rc);
 420        }
 421}
 422
 423sub file_diff
 424{
 425        my ($prompt) = @_;
 426
 427        if (defined($prompt)) {
 428                if ($prompt) {
 429                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 430                } else {
 431                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 432                }
 433        }
 434
 435        $ENV{GIT_PAGER} = '';
 436        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 437
 438        # ActiveState Perl for Win32 does not implement POSIX semantics of
 439        # exec* system call. It just spawns the given executable and finishes
 440        # the starting program, exiting with code 0.
 441        # system will at least catch the errors returned by git diff,
 442        # allowing the caller of git difftool better handling of failures.
 443        my $rc = system('git', 'diff', @ARGV);
 444        exit($rc | ($rc >> 8));
 445}
 446
 447main();