[PATCHv3] 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.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
---
 gitweb/gitweb.perl |   26 ++++++++++++++++++++++++--
 1 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 75d4178..7b4f2d3 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -560,7 +560,9 @@ 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/action/branch:filename" or "project.git/action/branch:dir/"
 		# we could use git_get_type(branch:pathname), but it needs $git_dir
@@ -569,7 +571,11 @@ 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);
@@ -579,6 +585,22 @@ sub evaluate_path_info {
 		$hash      ||= validate_refname($refname);
 		$hash_base ||= validate_refname($refname);
 	}
+	# the parent part might be missing the pathname, in which case we use the $file_name, if present
+	if (defined $parentrefname) {
+		$hash_parent_base ||= validate_refname($parentrefname);
+		if ($parentpathname) {
+			$parentpathname =~ s,^/+,,;
+			$parentpathname =~ s,/$,,;
+			$file_parent ||= validate_pathname($parentpathname);
+		} else {
+			$file_parent ||= $file_name
+		}
+		if (defined $file_parent) {
+			$hash_parent ||= git_get_hash_by_path($hash_parent_base, $file_parent);
+		} else {
+			$hash_parent ||= validate_refname($parentrefname);
+		}
+	}
 }
 evaluate_path_info();
 
-- 
1.5.6.5