[PATCHv4] 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 3e5b2b7..89e360f 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -534,7 +534,9 @@ if ($path_info && !defined $action) {
 
 # we can now parse ref and pathnames in PATH_INFO
 if ($path_info) {
-	my ($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 $git_dir
@@ -543,7 +545,11 @@ if ($path_info) {
 			$input_params{'action'} ||= "tree";
 			$pathname =~ s,/$,,;
 		} else {
-			$input_params{'action'}  ||= "blob_plain";
+			if ($parentrefname) {
+				$input_params{'action'} ||= "blobdiff_plain";
+			} else {
+				$input_params{'action'} ||= "blob_plain";
+			}
 		}
 		$input_params{'hash_base'} ||= $refname;
 		$input_params{'file_name'} ||= $pathname;
@@ -553,6 +559,22 @@ if ($path_info) {
 		$input_params{'hash'}      ||= $refname;
 		$input_params{'hash_base'} ||= $refname;
 	}
+	# the parent part might be missing the pathname, in which case we use the $file_name, if present
+	if (defined $parentrefname) {
+		$input_params{'hash_parent_base'} ||= $parentrefname;
+		if ($parentpathname) {
+			$parentpathname =~ s,^/+,,;
+			$parentpathname =~ s,/$,,;
+			$input_params{'file_parent'} ||= $parentpathname;
+		} else {
+			$input_params{'file_parent'} ||= $input_params{'file_name'};
+		}
+		if (defined $input_params{'file_parent'}) {
+			$input_params{'hash_parent'} ||= git_get_hash_by_path($input_params{'hash_parent_base'}, $input_params{'file_parent'});
+		} else {
+			$input_params{'hash_parent'} ||= $parentrefname;
+		}
+	}
 }
 
 # and now the rest of the validation
-- 
1.5.6.5