[PATCH/RFC] git-svn: New flag to add a file in empty directories

From

Ray Chen <rchen@cs.umd.edu>

Date

May 17, 2011, 22:00 UTC

Message-ID

<1305669635-10861-1-git-send-email-rchen@cs.umd.edu>

Signed-off-by: Ray Chen <rchen@cs.umd.edu>
---

 git-svn.perl |   91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/git-svn.perl b/git-svn.perl
index 0fd2fd2..64a4607 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -89,6 +89,7 @@ my ($_stdin, $_help, $_edit,
 	$_prefix, $_no_checkout, $_url, $_verbose,
 	$_git_format, $_commit_url, $_tag, $_merge_info);
 $Git::SVN::_follow_parent = 1;
+$SVN::Git::Fetcher::_placeholder_filename = ".gitignore";
 $_q ||= 0;
 my %remote_opts = ( 'username=s' => \$Git::SVN::Prompt::_username,
                     'config-dir=s' => \$Git::SVN::Ra::config_dir,
@@ -134,11 +135,19 @@ my %cmt_opts = ( 'edit|e' => \$_edit,
 my %cmd = (
 	fetch => [ \&cmd_fetch, "Download new revisions from SVN",
 			{ 'revision|r=s' => \$_revision,
+			  'preserve-empty-dirs' =>
+				\$SVN::Git::Fetcher::_preserve_empty_dirs,
+			  'placeholder-filename=s' =>
+				\$SVN::Git::Fetcher::_placeholder_filename,
 			  'fetch-all|all' => \$_fetch_all,
 			  'parent|p' => \$_fetch_parent,
 			   %fc_opts } ],
 	clone => [ \&cmd_clone, "Initialize and fetch revisions",
 			{ 'revision|r=s' => \$_revision,
+			  'preserve-empty-dirs' =>
+				\$SVN::Git::Fetcher::_preserve_empty_dirs,
+			  'placeholder-filename=s' =>
+				\$SVN::Git::Fetcher::_placeholder_filename,
 			   %fc_opts, %init_opts } ],
 	init => [ \&cmd_init, "Initialize a repo for tracking" .
 			  " (requires URL argument)",
@@ -4076,12 +4085,12 @@ sub _read_password {
 }
 
 package SVN::Git::Fetcher;
-use vars qw/@ISA/;
+use vars qw/@ISA $_ignore_regex $_preserve_empty_dirs $_placeholder_filename/;
 use strict;
 use warnings;
 use Carp qw/croak/;
+use File::Basename qw/dirname/;
 use IO::File qw//;
-use vars qw/$_ignore_regex/;
 
 # file baton members: path, mode_a, mode_b, pool, fh, blob, base
 sub new {
@@ -4100,6 +4109,7 @@ sub new {
 	$self->{file_prop} = {};
 	$self->{absent_dir} = {};
 	$self->{absent_file} = {};
+	$self->{deleted_gpath} = [];
 	$self->{gii} = $git_svn->tmp_index_do(sub { Git::IndexInfo->new });
 	$self->{pathnameencoding} = Git::config('svn.pathnameencoding');
 	$self;
@@ -4223,6 +4233,7 @@ sub delete_entry {
 		$self->{gii}->remove($gpath);
 		print "\tD\t$gpath\n" unless $::_q;
 	}
+	push @{$self->{deleted_gpath}}, $gpath;
 	$self->{empty}->{$path} = 0;
 	undef;
 }
@@ -4273,6 +4284,7 @@ sub add_directory {
 			chomp;
 			$self->{gii}->remove($_);
 			print "\tD\t$_\n" unless $::_q;
+			push @{$self->{deleted_gpath}}, $gpath;
 		}
 		command_close_pipe($ls, $ctx);
 		$self->{empty}->{$path} = 0;
@@ -4443,12 +4455,87 @@ sub abort_edit {
 
 sub close_edit {
 	my $self = shift;
+
+	if ($_preserve_empty_dirs) {
+		my @empty_dirs;
+
+		# Any entry flagged as empty that also has an associated
+		# dir_prop represents a newly created empty directory.
+		foreach my $i (keys %{$self->{empty}}) {
+			push @empty_dirs, $i if exists $self->{dir_prop}->{$i};
+		}
+
+		# Search for directories that have become empty due subsequent
+		# file deletes.
+		push @empty_dirs, $self->find_empty_directories();
+
+		# Finally, add a placeholder file to each empty directory.
+		$self->add_placeholder_file($_) foreach (@empty_dirs);
+	}
+
 	$self->{git_commit_ok} = 1;
 	$self->{nr} = $self->{gii}->{nr};
 	delete $self->{gii};
 	$self->SUPER::close_edit(@_);
 }
 
+sub find_empty_directories {
+	my ($self) = @_;
+	my @empty_dirs;
+	my %dirs = map { dirname($_) => 1 } @{$self->{deleted_gpath}};
+
+	foreach my $dir (sort keys %dirs) {
+		next if $dir eq ".";
+
+		# If there have been any additions to this directory, there is
+		# no reason to check if it is empty.
+		my $skip_added = 0;
+		foreach my $t (qw/dir_prop file_prop/) {
+			foreach my $path (keys %{ $self->{$t} }) {
+				if (exists $self->{$t}->{dirname($path)}) {
+					$skip_added = 1;
+					last;
+				}
+			}
+			last if $skip_added;
+		}
+		next if $skip_added;
+
+		# Use `git ls-tree` to get the filenames of this directory
+		# that existed prior to this particular commit.
+		my $ls = command('ls-tree', '-z', '--name-only',
+				 $self->{c}, "$dir/");
+		my %files = map { $_ => 1 } split(/\0/, $ls);
+
+		# Remove the filenames that were deleted during this commit.
+		delete $files{$_} foreach (@{$self->{deleted_gpath}});
+
+		# Report the directory if there are no filenames left.
+		push @empty_dirs, $dir unless (scalar %files);
+	}
+	@empty_dirs;
+}
+
+sub add_placeholder_file {
+	my ($self, $dir) = @_;
+	my $path = "$dir/$_placeholder_filename";
+	my $gpath = $self->git_path($path);
+
+	my $fh = $::_repository->temp_acquire($gpath);
+	my $hash = $::_repository->hash_and_insert_object(Git::temp_path($fh));
+	Git::temp_release($fh, 1);
+	$self->{gii}->update('100644', $hash, $gpath) or croak $!;
+
+	# The following two lines don't seem to be necessary, but I'm not
+	# familiar enough with SVN properties to know if correctness is
+	# compromised without them.
+#	$self->{file_prop}->{$path} = $self->{dir_prop}->{$dir};
+#	$self->add_file($path, { 'path' => $dir }, undef, '-1');
+
+	# The directory should no longer be considered empty.
+	delete $self->{empty}->{$dir} if exists $self->{empty}->{$dir};
+}
+
 package SVN::Git::Editor;
 use vars qw/@ISA $_rmdir $_cp_similarity $_find_copies_harder $_rename_limit/;
 use strict;

-- 
1.7.5.1