[PATCH 1/2] gitweb: parse parent..current syntax from pathinfo

[Giuseppe Bilotta <giuseppe.bilotta@gmail.com>]

This makes it possible to use an URL such as
$project/somebranch..otherbranch:/filename to get a diff between
different version of a file. Paths like
$project/$action/somebranch:/somefile..otherbranch:/otherfile are parsed
as well.
---

This patch and the next apply on top of my previous two
gitweb pathinfo patches. 

I realize that these patches of mine coming through in burst
can get pretty annoying, but I honestly wasn't planning of
making so many changes to the path info feature. So let me
know if it's better to resend the patches in a series.

Hopefully, with this patch and the next the series should be
complete, as most commands will now be able to get all of
their parameters from the path without using CGI parameters.

 gitweb/gitweb.perl |   22 ++++++++++++++++++++--
 1 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 9e90017..8364b71 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -578,7 +578,9 @@ sub evaluate_path_info {
 		$action  = undef;
 	}
 
-	my ($refname, $pathname) = split(/:/, $path_info, 2);
+	$path_info =~ /^((.+?)(:(.+))?\.\.)?(.+?)(:(.+))?$/;
+	my ($parentrefname, $parentpathname, $refname, $pathname) = (
+		$2, $4, $5, $7);
 	if (defined $pathname) {
 		# we got "project.git/branch:filename" or "project.git/branch:dir/"
 		# we could use git_get_type(branch:pathname), but it needs $git_dir
@@ -587,11 +589,27 @@ sub evaluate_path_info {
 			$action  ||= "tree";
 			$pathname =~ s,/$,,;
 		} else {
-			$action  ||= "blob_plain";
+			if ($parentrefname) {
+				$action ||= "blobdiff_plain";
+			} else {
+				$action  ||= "blob_plain";
+			}
 		}
 		$hash_base ||= validate_refname($refname);
 		$file_name ||= validate_pathname($pathname);
 		$hash      ||= git_get_hash_by_path($hash_base, $file_name);
+
+		if ($parentrefname) {
+			$hash_parent_base ||= validate_refname($parentrefname);
+			if ($parentpathname) {
+				$parentpathname =~ s,^/+,,;
+				$parentpathname =~ s,/$,,;
+				$file_parent ||= validate_pathname($parentpathname);
+			} else {
+				$file_parent ||= $file_name
+			}
+			$hash_parent ||= git_get_hash_by_path($hash_parent_base, $file_parent);
+		}
 	} elsif (defined $refname) {
 		# we got "project.git/branch"
 		$action    ||= "shortlog";
-- 
1.5.6.3