git-svn: make --repack work consistently between fetch and multi-fetch

Since fetch reforks itself at most every 1000 revisions, we
need to update the counter in the parent process to have a
working count if we set our repack interval to be > ~1000
revisions.  multi-fetch has always done this correctly
because of an extra process; now fetch uses the extra process;
as well.

While we're at it, only compile the $sha1 regex that checks for
repacking once.
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

git-svn.perl

@@ -102,7 +102,7 @@
 );
 
 my %cmd = (
-	fetch => [ \&fetch, "Download new revisions from SVN",
+	fetch => [ \&cmd_fetch, "Download new revisions from SVN",
 			{ 'revision|r=s' => \$_revision, %fc_opts } ],
 	init => [ \&init, "Initialize a repo for tracking" .
 			  " (requires URL argument)",
@@ -293,6 +293,10 @@ sub init {
 	setup_git_svn();
 }
 
+sub cmd_fetch {
+	fetch_child_id($GIT_SVN, @_);
+}
+
 sub fetch {
 	check_upgrade_needed();
 	$SVN_URL ||= file_to_s("$GIT_SVN_DIR/info/url");
@@ -836,7 +840,6 @@ sub fetch_child_id {
 	my $ref = "$GIT_DIR/refs/remotes/$id";
 	defined(my $pid = open my $fh, '-|') or croak $!;
 	if (!$pid) {
-		$_repack = undef;
 		$GIT_SVN = $ENV{GIT_SVN_ID} = $id;
 		init_vars();
 		fetch(@_);
@@ -844,7 +847,7 @@ sub fetch_child_id {
 	}
 	while (<$fh>) {
 		print $_;
-		check_repack() if (/^r\d+ = $sha1/);
+		check_repack() if (/^r\d+ = $sha1/o);
 	}
 	close $fh or croak $?;
 }
@@ -1407,7 +1410,6 @@ sub git_commit {
 
 	# this output is read via pipe, do not change:
 	print "r$log_msg->{revision} = $commit\n";
-	check_repack();
 	return $commit;
 }