Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit difftool: Wrap long lines for readability (a4cd5be)
   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);
  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$_\n" for (sort(@notfound));
 106
 107        print << 'EOF';
 108
 109NOTE: Some of the tools listed above only work in a windowed
 110environment. If run in a terminal-only session, they will fail.
 111EOF
 112        exit(0);
 113}
 114
 115sub setup_dir_diff
 116{
 117        my ($repo, $workdir, $symlinks) = @_;
 118
 119        # Run the diff; exit immediately if no diff found
 120        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 121        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 122        # by Git->repository->command*.
 123        my $repo_path = $repo->repo_path();
 124        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
 125        my $diffrepo = Git->repository(%repo_args);
 126
 127        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 128        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 129        exit(0) if (length($diffrtn) == 0);
 130
 131        # Setup temp directories
 132        my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 1, TMPDIR => 1);
 133        my $ldir = "$tmpdir/left";
 134        my $rdir = "$tmpdir/right";
 135        mkpath($ldir) or die $!;
 136        mkpath($rdir) or die $!;
 137
 138        # Build index info for left and right sides of the diff
 139        my $submodule_mode = '160000';
 140        my $symlink_mode = '120000';
 141        my $null_mode = '0' x 6;
 142        my $null_sha1 = '0' x 40;
 143        my $lindex = '';
 144        my $rindex = '';
 145        my %submodule;
 146        my %symlink;
 147        my @working_tree = ();
 148        my @rawdiff = split('\0', $diffrtn);
 149
 150        my $i = 0;
 151        while ($i < $#rawdiff) {
 152                if ($rawdiff[$i] =~ /^::/) {
 153                        warn << 'EOF';
 154Combined diff formats ('-c' and '--cc') are not supported in
 155directory diff mode ('-d' and '--dir-diff').
 156EOF
 157                        exit(1);
 158                }
 159
 160                my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 161                        split(' ', substr($rawdiff[$i], 1));
 162                my $src_path = $rawdiff[$i + 1];
 163                my $dst_path;
 164
 165                if ($status =~ /^[CR]/) {
 166                        $dst_path = $rawdiff[$i + 2];
 167                        $i += 3;
 168                } else {
 169                        $dst_path = $src_path;
 170                        $i += 2;
 171                }
 172
 173                if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 174                        $submodule{$src_path}{left} = $lsha1;
 175                        if ($lsha1 ne $rsha1) {
 176                                $submodule{$dst_path}{right} = $rsha1;
 177                        } else {
 178                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 179                        }
 180                        next;
 181                }
 182
 183                if ($lmode eq $symlink_mode) {
 184                        $symlink{$src_path}{left} =
 185                                $diffrepo->command_oneline('show', "$lsha1");
 186                }
 187
 188                if ($rmode eq $symlink_mode) {
 189                        $symlink{$dst_path}{right} =
 190                                $diffrepo->command_oneline('show', "$rsha1");
 191                }
 192
 193                if ($lmode ne $null_mode and $status !~ /^C/) {
 194                        $lindex .= "$lmode $lsha1\t$src_path\0";
 195                }
 196
 197                if ($rmode ne $null_mode) {
 198                        if ($rsha1 ne $null_sha1) {
 199                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 200                        } else {
 201                                push(@working_tree, $dst_path);
 202                        }
 203                }
 204        }
 205
 206        # If $GIT_DIR is not set prior to calling 'git update-index' and
 207        # 'git checkout-index', then those commands will fail if difftool
 208        # is called from a directory other than the repo root.
 209        my $must_unset_git_dir = 0;
 210        if (not defined($ENV{GIT_DIR})) {
 211                $must_unset_git_dir = 1;
 212                $ENV{GIT_DIR} = $repo_path;
 213        }
 214
 215        # Populate the left and right directories based on each index file
 216        my ($inpipe, $ctx);
 217        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 218        ($inpipe, $ctx) =
 219                $repo->command_input_pipe(qw(update-index -z --index-info));
 220        print($inpipe $lindex);
 221        $repo->command_close_pipe($inpipe, $ctx);
 222        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 223        exit($rc | ($rc >> 8)) if ($rc != 0);
 224
 225        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 226        ($inpipe, $ctx) =
 227                $repo->command_input_pipe(qw(update-index -z --index-info));
 228        print($inpipe $rindex);
 229        $repo->command_close_pipe($inpipe, $ctx);
 230        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 231        exit($rc | ($rc >> 8)) if ($rc != 0);
 232
 233        # If $GIT_DIR was explicitly set just for the update/checkout
 234        # commands, then it should be unset before continuing.
 235        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 236        delete($ENV{GIT_INDEX_FILE});
 237
 238        # Changes in the working tree need special treatment since they are
 239        # not part of the index
 240        for my $file (@working_tree) {
 241                my $dir = dirname($file);
 242                unless (-d "$rdir/$dir") {
 243                        mkpath("$rdir/$dir") or die $!;
 244                }
 245                if ($symlinks) {
 246                        symlink("$workdir/$file", "$rdir/$file") or die $!;
 247                } else {
 248                        copy("$workdir/$file", "$rdir/$file") or die $!;
 249                        my $mode = stat("$workdir/$file")->mode;
 250                        chmod($mode, "$rdir/$file") or die $!;
 251                }
 252        }
 253
 254        # Changes to submodules require special treatment. This loop writes a
 255        # temporary file to both the left and right directories to show the
 256        # change in the recorded SHA1 for the submodule.
 257        for my $path (keys %submodule) {
 258                if (defined($submodule{$path}{left})) {
 259                        write_to_file("$ldir/$path", "Subproject commit $submodule{$path}{left}");
 260                }
 261                if (defined($submodule{$path}{right})) {
 262                        write_to_file("$rdir/$path", "Subproject commit $submodule{$path}{right}");
 263                }
 264        }
 265
 266        # Symbolic links require special treatment. The standard "git diff"
 267        # shows only the link itself, not the contents of the link target.
 268        # This loop replicates that behavior.
 269        for my $path (keys %symlink) {
 270                if (defined($symlink{$path}{left})) {
 271                        write_to_file("$ldir/$path", $symlink{$path}{left});
 272                }
 273                if (defined($symlink{$path}{right})) {
 274                        write_to_file("$rdir/$path", $symlink{$path}{right});
 275                }
 276        }
 277
 278        return ($ldir, $rdir, @working_tree);
 279}
 280
 281sub write_to_file
 282{
 283        my $path = shift;
 284        my $value = shift;
 285
 286        # Make sure the path to the file exists
 287        my $dir = dirname($path);
 288        unless (-d "$dir") {
 289                mkpath("$dir") or die $!;
 290        }
 291
 292        # If the file already exists in that location, delete it.  This
 293        # is required in the case of symbolic links.
 294        unlink("$path");
 295
 296        open(my $fh, '>', "$path") or die $!;
 297        print($fh $value);
 298        close($fh);
 299}
 300
 301sub main
 302{
 303        # parse command-line options. all unrecognized options and arguments
 304        # are passed through to the 'git diff' command.
 305        my %opts = (
 306                difftool_cmd => undef,
 307                dirdiff => undef,
 308                extcmd => undef,
 309                gui => undef,
 310                help => undef,
 311                prompt => undef,
 312                symlinks => $^O ne 'MSWin32' && $^O ne 'msys',
 313                tool_help => undef,
 314        );
 315        GetOptions('g|gui!' => \$opts{gui},
 316                'd|dir-diff' => \$opts{dirdiff},
 317                'h' => \$opts{help},
 318                'prompt!' => \$opts{prompt},
 319                'y' => sub { $opts{prompt} = 0; },
 320                'symlinks' => \$opts{symlinks},
 321                'no-symlinks' => sub { $opts{symlinks} = 0; },
 322                't|tool:s' => \$opts{difftool_cmd},
 323                'tool-help' => \$opts{tool_help},
 324                'x|extcmd:s' => \$opts{extcmd});
 325
 326        if (defined($opts{help})) {
 327                usage(0);
 328        }
 329        if (defined($opts{tool_help})) {
 330                print_tool_help();
 331        }
 332        if (defined($opts{difftool_cmd})) {
 333                if (length($opts{difftool_cmd}) > 0) {
 334                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 335                } else {
 336                        print "No <tool> given for --tool=<tool>\n";
 337                        usage(1);
 338                }
 339        }
 340        if (defined($opts{extcmd})) {
 341                if (length($opts{extcmd}) > 0) {
 342                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 343                } else {
 344                        print "No <cmd> given for --extcmd=<cmd>\n";
 345                        usage(1);
 346                }
 347        }
 348        if ($opts{gui}) {
 349                my $guitool = Git::config('diff.guitool');
 350                if (length($guitool) > 0) {
 351                        $ENV{GIT_DIFF_TOOL} = $guitool;
 352                }
 353        }
 354
 355        # In directory diff mode, 'git-difftool--helper' is called once
 356        # to compare the a/b directories.  In file diff mode, 'git diff'
 357        # will invoke a separate instance of 'git-difftool--helper' for
 358        # each file that changed.
 359        if (defined($opts{dirdiff})) {
 360                dir_diff($opts{extcmd}, $opts{symlinks});
 361        } else {
 362                file_diff($opts{prompt});
 363        }
 364}
 365
 366sub dir_diff
 367{
 368        my ($extcmd, $symlinks) = @_;
 369
 370        my $rc;
 371        my $repo = Git->repository();
 372
 373        my $workdir = find_worktree($repo);
 374        my ($a, $b, @worktree) = setup_dir_diff($repo, $workdir, $symlinks);
 375        if (defined($extcmd)) {
 376                $rc = system($extcmd, $a, $b);
 377        } else {
 378                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 379                $rc = system('git', 'difftool--helper', $a, $b);
 380        }
 381
 382        exit($rc | ($rc >> 8)) if ($rc != 0);
 383
 384        # If the diff including working copy files and those
 385        # files were modified during the diff, then the changes
 386        # should be copied back to the working tree.
 387        # Do not copy back files when symlinks are used and the
 388        # external tool did not replace the original link with a file.
 389        for my $file (@worktree) {
 390                next if $symlinks && -l "$b/$file";
 391                next if ! -f "$b/$file";
 392
 393                my $diff = compare("$b/$file", "$workdir/$file");
 394                if ($diff == 0) {
 395                        next;
 396                } elsif ($diff == -1) {
 397                        my $errmsg = "warning: Could not compare ";
 398                        $errmsg += "'$b/$file' with '$workdir/$file'\n";
 399                        warn $errmsg;
 400                } elsif ($diff == 1) {
 401                        copy("$b/$file", "$workdir/$file") or die $!;
 402                        my $mode = stat("$b/$file")->mode;
 403                        chmod($mode, "$workdir/$file") or die $!;
 404                }
 405        }
 406        exit(0);
 407}
 408
 409sub file_diff
 410{
 411        my ($prompt) = @_;
 412
 413        if (defined($prompt)) {
 414                if ($prompt) {
 415                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 416                } else {
 417                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 418                }
 419        }
 420
 421        $ENV{GIT_PAGER} = '';
 422        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 423
 424        # ActiveState Perl for Win32 does not implement POSIX semantics of
 425        # exec* system call. It just spawns the given executable and finishes
 426        # the starting program, exiting with code 0.
 427        # system will at least catch the errors returned by git diff,
 428        # allowing the caller of git difftool better handling of failures.
 429        my $rc = system('git', 'diff', @ARGV);
 430        exit($rc | ($rc >> 8));
 431}
 432
 433main();