[PATCH 4/7] gitweb: Add parse_rev_list for later use

[Jakub Narebski <jnareb@gmail.com>]

Add parse_rev_list to generate _parsed_ list of revisions, combining
getting the list of revisions, and parsing of individual revisions
into one subroutine.  It is to avoid code like below

	open my $fd, "-|", git_cmd(), "rev-list", $limit, $hash
		or die_error(undef, "Open git-rev-list failed");
	my @revlist = map { chomp; $_ } <$fd>;

	...

	foreach my $commit (@revlist) {
		my %co = parse_commit($commit);

where parse_commit subroutine calls git-rev-list with '--max-count=1'
to parse individual commit.  Using parse_rev_list will avoid
unnecessary forks.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
 gitweb/gitweb.perl |   29 +++++++++++++++++++++++++++++
 1 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 2191853..8aeca52 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -1125,6 +1125,35 @@ sub git_get_refs_list {
 	return \@reflist;
 }
 
+# To use only one invocation of git-rev-list, instead of getting
+# the list of revisions and then using git-rev-list per revision
+# to parse individual commits.
+#
+# parse_rev_list parameters are passed to git-rev-list, so they should
+# include at least starting revision; just in case we default to HEAD
+sub parse_rev_list {
+	my @rev_opts = @_;
+	my @revlist;
+
+	@rev_opts = ("HEAD") unless @rev_opts;
+
+	local $/ = "\0";
+	open my $fd, "-|", git_cmd(), "rev-list", "--header", "--parents", @rev_opts
+		or return \@revlist;
+
+	while (my $revinfo = <$fd>) {
+		chomp $revinfo;
+		my @commit_lines = split '\n', $revinfo;
+		my %co = parse_commit(undef, \@commit_lines);
+
+		push @revlist, \%co;
+	}
+
+	close $fd;
+
+	return wantarray ? @revlist : \@revlist;
+}
+
 ## ----------------------------------------------------------------------
 ## filesystem-related functions
 
-- 
1.4.2