[PATCH 02/36] lei_store: use per-machine refname as git HEAD

[Eric Wong <e@80x24.org>]

It may be helpful to identify the source of messages
and perhaps avoid conflicting history.

On the other hand, this may be a terrible idea for users who
move portable storage (e.g. USB sticks) across computers...
---
 lib/PublicInbox/Import.pm   | 10 ++++++----
 lib/PublicInbox/LeiStore.pm | 21 ++++++++++++++++++++-
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index 7258e848..60cff9c2 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -463,16 +463,18 @@ EOD
 EOC
 
 sub init_bare {
-	my ($dir) = @_; # or self
+	my ($dir, $head) = @_; # or self
 	$dir = $dir->{git}->{git_dir} if ref($dir);
 	require File::Path;
 	File::Path::mkpath([ map { "$dir/$_" } qw(objects/info refs/heads) ]);
 	$INIT_FILES[1] //= 'ref: '.default_branch."\n";
-	for (my $i = 0; $i < @INIT_FILES; $i++) {
-		my $f = $dir.'/'.$INIT_FILES[$i++];
+	my @fn_contents = @INIT_FILES;
+	$fn_contents[1] = "ref: refs/heads/$head\n" if defined $head;
+	while (my ($fn, $contents) = splice(@fn_contents, 0, 2)) {
+		my $f = $dir.'/'.$fn;
 		next if -f $f;
 		open my $fh, '>', $f or die "open $f: $!";
-		print $fh $INIT_FILES[$i] or die "print $f: $!";
+		print $fh $contents or die "print $f: $!";
 		close $fh or die "close $f: $!";
 	}
 }
diff --git a/lib/PublicInbox/LeiStore.pm b/lib/PublicInbox/LeiStore.pm
index 553adbc8..a17c7bab 100644
--- a/lib/PublicInbox/LeiStore.pm
+++ b/lib/PublicInbox/LeiStore.pm
@@ -60,6 +60,24 @@ sub git_ident ($) {
 		('lei user', 'x@example.com')
 }
 
+# We will support users combining storage across multiple machines
+# somehow.  Use per-machine refnames to make it easy-to-identify
+# where a message came from
+sub host_head () {
+	state $h = do {
+		my $x = PublicInbox::ExtSearchIdx::host_ident;
+		# Similar rules found in git.git/remote.c::valid_remote_nick
+		# and git.git/refs.c::check_refname_component
+		$x =~ s!(?:\.lock|/)+\z!!gs; # must not end with ".lock" or "/"
+		$x =~ tr/././s; # no dot-dot, collapse them
+		$x =~ s/@\{/\@-/gs;
+		$x =~ s/\A\./-/s;
+		# no "*", ":", "?", "[", "\", "^", "~", SP, TAB; "]" is OK
+		$x =~ tr^a-zA-Z0-9!"#$%&'()+,\-.;<=>@]_`{|}^-^c;
+		$x
+	};
+}
+
 sub importer {
 	my ($self) = @_;
 	my $max;
@@ -78,8 +96,8 @@ sub importer {
 	while (1) {
 		my $latest = "$pfx/$max.git";
 		my $old = -e $latest;
+		PublicInbox::Import::init_bare($latest, host_head);
 		my $git = PublicInbox::Git->new($latest);
-		PublicInbox::Import::init_bare({ git => $git });
 		$git->qx(qw(config core.sharedRepository 0600)) if !$old;
 		my $packed_bytes = $git->packed_bytes;
 		my $unpacked_bytes = $packed_bytes / $self->packing_factor;
@@ -92,6 +110,7 @@ sub importer {
 		$im->{bytes_added} = int($packed_bytes / $self->packing_factor);
 		$im->{lock_path} = undef;
 		$im->{path_type} = 'v2';
+		$im->{'ref'} = host_head;
 		return $im;
 	}
 }