Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit oneway_merge(): only lstat() when told to update worktree (686b2de)
   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
  26my @tools;
  27my @working_tree;
  28my $rc;
  29my $repo = Git->repository();
  30my $repo_path = $repo->repo_path();
  31
  32sub usage
  33{
  34        my $exitcode = shift;
  35        print << 'USAGE';
  36usage: git difftool [-t|--tool=<tool>] [--tool-help]
  37                    [-x|--extcmd=<cmd>]
  38                    [-g|--gui] [--no-gui]
  39                    [--prompt] [-y|--no-prompt]
  40                    [-d|--dir-diff]
  41                    ['git diff' options]
  42USAGE
  43        exit($exitcode);
  44}
  45
  46sub find_worktree
  47{
  48        # Git->repository->wc_path() does not honor changes to the working
  49        # tree location made by $ENV{GIT_WORK_TREE} or the 'core.worktree'
  50        # config variable.
  51        my $worktree;
  52        my $env_worktree = $ENV{GIT_WORK_TREE};
  53        my $core_worktree = Git::config('core.worktree');
  54
  55        if (defined($env_worktree) and (length($env_worktree) > 0)) {
  56                $worktree = $env_worktree;
  57        } elsif (defined($core_worktree) and (length($core_worktree) > 0)) {
  58                $worktree = $core_worktree;
  59        } else {
  60                $worktree = $repo->wc_path();
  61        }
  62
  63        return $worktree;
  64}
  65
  66my $workdir = find_worktree();
  67
  68sub filter_tool_scripts
  69{
  70        if (-d $_) {
  71                if ($_ ne ".") {
  72                        # Ignore files in subdirectories
  73                        $File::Find::prune = 1;
  74                }
  75        } else {
  76                if ((-f $_) && ($_ ne "defaults")) {
  77                        push(@tools, $_);
  78                }
  79        }
  80}
  81
  82sub print_tool_help
  83{
  84        my ($cmd, @found, @notfound);
  85        my $gitpath = Git::exec_path();
  86
  87        find(\&filter_tool_scripts, "$gitpath/mergetools");
  88
  89        foreach my $tool (@tools) {
  90                $cmd  = "TOOL_MODE=diff";
  91                $cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
  92                $cmd .= " && get_merge_tool_path $tool >/dev/null 2>&1";
  93                $cmd .= " && can_diff >/dev/null 2>&1";
  94                if (system('sh', '-c', $cmd) == 0) {
  95                        push(@found, $tool);
  96                } else {
  97                        push(@notfound, $tool);
  98                }
  99        }
 100
 101        print "'git difftool --tool=<tool>' may be set to one of the following:\n";
 102        print "\t$_\n" for (sort(@found));
 103
 104        print "\nThe following tools are valid, but not currently available:\n";
 105        print "\t$_\n" for (sort(@notfound));
 106
 107        print "\nNOTE: Some of the tools listed above only work in a windowed\n";
 108        print "environment. If run in a terminal-only session, they will fail.\n";
 109
 110        exit(0);
 111}
 112
 113sub setup_dir_diff
 114{
 115        # Run the diff; exit immediately if no diff found
 116        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
 117        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
 118        # by Git->repository->command*.
 119        my $diffrepo = Git->repository(Repository => $repo_path, WorkingCopy => $workdir);
 120        my $diffrtn = $diffrepo->command_oneline('diff', '--raw', '--no-abbrev', '-z', @ARGV);
 121        exit(0) if (length($diffrtn) == 0);
 122
 123        # Setup temp directories
 124        my $tmpdir = tempdir('git-diffall.XXXXX', CLEANUP => 1, TMPDIR => 1);
 125        my $ldir = "$tmpdir/left";
 126        my $rdir = "$tmpdir/right";
 127        mkpath($ldir) or die $!;
 128        mkpath($rdir) or die $!;
 129
 130        # Build index info for left and right sides of the diff
 131        my $submodule_mode = '160000';
 132        my $symlink_mode = '120000';
 133        my $null_mode = '0' x 6;
 134        my $null_sha1 = '0' x 40;
 135        my $lindex = '';
 136        my $rindex = '';
 137        my %submodule;
 138        my %symlink;
 139        my @rawdiff = split('\0', $diffrtn);
 140
 141        my $i = 0;
 142        while ($i < $#rawdiff) {
 143                if ($rawdiff[$i] =~ /^::/) {
 144                        print "Combined diff formats ('-c' and '--cc') are not supported in directory diff mode.\n";
 145                        exit(1);
 146                }
 147
 148                my ($lmode, $rmode, $lsha1, $rsha1, $status) = split(' ', substr($rawdiff[$i], 1));
 149                my $src_path = $rawdiff[$i + 1];
 150                my $dst_path;
 151
 152                if ($status =~ /^[CR]/) {
 153                        $dst_path = $rawdiff[$i + 2];
 154                        $i += 3;
 155                } else {
 156                        $dst_path = $src_path;
 157                        $i += 2;
 158                }
 159
 160                if (($lmode eq $submodule_mode) or ($rmode eq $submodule_mode)) {
 161                        $submodule{$src_path}{left} = $lsha1;
 162                        if ($lsha1 ne $rsha1) {
 163                                $submodule{$dst_path}{right} = $rsha1;
 164                        } else {
 165                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 166                        }
 167                        next;
 168                }
 169
 170                if ($lmode eq $symlink_mode) {
 171                        $symlink{$src_path}{left} = $diffrepo->command_oneline('show', "$lsha1");
 172                }
 173
 174                if ($rmode eq $symlink_mode) {
 175                        $symlink{$dst_path}{right} = $diffrepo->command_oneline('show', "$rsha1");
 176                }
 177
 178                if (($lmode ne $null_mode) and ($status !~ /^C/)) {
 179                        $lindex .= "$lmode $lsha1\t$src_path\0";
 180                }
 181
 182                if ($rmode ne $null_mode) {
 183                        if ($rsha1 ne $null_sha1) {
 184                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 185                        } else {
 186                                push(@working_tree, $dst_path);
 187                        }
 188                }
 189        }
 190
 191        # If $GIT_DIR is not set prior to calling 'git update-index' and
 192        # 'git checkout-index', then those commands will fail if difftool
 193        # is called from a directory other than the repo root.
 194        my $must_unset_git_dir = 0;
 195        if (not defined($ENV{GIT_DIR})) {
 196                $must_unset_git_dir = 1;
 197                $ENV{GIT_DIR} = $repo_path;
 198        }
 199
 200        # Populate the left and right directories based on each index file
 201        my ($inpipe, $ctx);
 202        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 203        ($inpipe, $ctx) = $repo->command_input_pipe(qw/update-index -z --index-info/);
 204        print($inpipe $lindex);
 205        $repo->command_close_pipe($inpipe, $ctx);
 206        $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 207        exit($rc | ($rc >> 8)) if ($rc != 0);
 208
 209        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 210        ($inpipe, $ctx) = $repo->command_input_pipe(qw/update-index -z --index-info/);
 211        print($inpipe $rindex);
 212        $repo->command_close_pipe($inpipe, $ctx);
 213        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 214        exit($rc | ($rc >> 8)) if ($rc != 0);
 215
 216        # If $GIT_DIR was explicitly set just for the update/checkout
 217        # commands, then it should be unset before continuing.
 218        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 219        delete($ENV{GIT_INDEX_FILE});
 220
 221        # Changes in the working tree need special treatment since they are
 222        # not part of the index
 223        for my $file (@working_tree) {
 224                my $dir = dirname($file);
 225                unless (-d "$rdir/$dir") {
 226                        mkpath("$rdir/$dir") or die $!;
 227                }
 228                copy("$workdir/$file", "$rdir/$file") or die $!;
 229                chmod(stat("$workdir/$file")->mode, "$rdir/$file") or die $!;
 230        }
 231
 232        # Changes to submodules require special treatment. This loop writes a
 233        # temporary file to both the left and right directories to show the
 234        # change in the recorded SHA1 for the submodule.
 235        for my $path (keys %submodule) {
 236                if (defined($submodule{$path}{left})) {
 237                        write_to_file("$ldir/$path", "Subproject commit $submodule{$path}{left}");
 238                }
 239                if (defined($submodule{$path}{right})) {
 240                        write_to_file("$rdir/$path", "Subproject commit $submodule{$path}{right}");
 241                }
 242        }
 243
 244        # Symbolic links require special treatment. The standard "git diff"
 245        # shows only the link itself, not the contents of the link target.
 246        # This loop replicates that behavior.
 247        for my $path (keys %symlink) {
 248                if (defined($symlink{$path}{left})) {
 249                        write_to_file("$ldir/$path", $symlink{$path}{left});
 250                }
 251                if (defined($symlink{$path}{right})) {
 252                        write_to_file("$rdir/$path", $symlink{$path}{right});
 253                }
 254        }
 255
 256        return ($ldir, $rdir);
 257}
 258
 259sub write_to_file
 260{
 261        my $path = shift;
 262        my $value = shift;
 263
 264        # Make sure the path to the file exists
 265        my $dir = dirname($path);
 266        unless (-d "$dir") {
 267                mkpath("$dir") or die $!;
 268        }
 269
 270        # If the file already exists in that location, delete it.  This
 271        # is required in the case of symbolic links.
 272        unlink("$path");
 273
 274        open(my $fh, '>', "$path") or die $!;
 275        print($fh $value);
 276        close($fh);
 277}
 278
 279# parse command-line options. all unrecognized options and arguments
 280# are passed through to the 'git diff' command.
 281my ($difftool_cmd, $dirdiff, $extcmd, $gui, $help, $prompt, $tool_help);
 282GetOptions('g|gui!' => \$gui,
 283        'd|dir-diff' => \$dirdiff,
 284        'h' => \$help,
 285        'prompt!' => \$prompt,
 286        'y' => sub { $prompt = 0; },
 287        't|tool:s' => \$difftool_cmd,
 288        'tool-help' => \$tool_help,
 289        'x|extcmd:s' => \$extcmd);
 290
 291if (defined($help)) {
 292        usage(0);
 293}
 294if (defined($tool_help)) {
 295        print_tool_help();
 296}
 297if (defined($difftool_cmd)) {
 298        if (length($difftool_cmd) > 0) {
 299                $ENV{GIT_DIFF_TOOL} = $difftool_cmd;
 300        } else {
 301                print "No <tool> given for --tool=<tool>\n";
 302                usage(1);
 303        }
 304}
 305if (defined($extcmd)) {
 306        if (length($extcmd) > 0) {
 307                $ENV{GIT_DIFFTOOL_EXTCMD} = $extcmd;
 308        } else {
 309                print "No <cmd> given for --extcmd=<cmd>\n";
 310                usage(1);
 311        }
 312}
 313if ($gui) {
 314        my $guitool = '';
 315        $guitool = Git::config('diff.guitool');
 316        if (length($guitool) > 0) {
 317                $ENV{GIT_DIFF_TOOL} = $guitool;
 318        }
 319}
 320
 321# In directory diff mode, 'git-difftool--helper' is called once
 322# to compare the a/b directories.  In file diff mode, 'git diff'
 323# will invoke a separate instance of 'git-difftool--helper' for
 324# each file that changed.
 325if (defined($dirdiff)) {
 326        my ($a, $b) = setup_dir_diff();
 327        if (defined($extcmd)) {
 328                $rc = system($extcmd, $a, $b);
 329        } else {
 330                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 331                $rc = system('git', 'difftool--helper', $a, $b);
 332        }
 333
 334        exit($rc | ($rc >> 8)) if ($rc != 0);
 335
 336        # If the diff including working copy files and those
 337        # files were modified during the diff, then the changes
 338        # should be copied back to the working tree
 339        for my $file (@working_tree) {
 340                if (-e "$b/$file" && compare("$b/$file", "$workdir/$file")) {
 341                        copy("$b/$file", "$workdir/$file") or die $!;
 342                        chmod(stat("$b/$file")->mode, "$workdir/$file") or die $!;
 343                }
 344        }
 345} else {
 346        if (defined($prompt)) {
 347                if ($prompt) {
 348                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 349                } else {
 350                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 351                }
 352        }
 353
 354        $ENV{GIT_PAGER} = '';
 355        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 356
 357        # ActiveState Perl for Win32 does not implement POSIX semantics of
 358        # exec* system call. It just spawns the given executable and finishes
 359        # the starting program, exiting with code 0.
 360        # system will at least catch the errors returned by git diff,
 361        # allowing the caller of git difftool better handling of failures.
 362        my $rc = system('git', 'diff', @ARGV);
 363        exit($rc | ($rc >> 8));
 364}