gitweb: generate parent..current URLs

If use_pathinfo is enabled, href now creates links that contain paths in
the form $project/$action/oldhash:/oldname..newhash:/newname for actions
that use hash_parent etc.

If any of the filename contains two consecutive dots, it's kept as a CGI
parameter since the resulting path would otherwise be ambiguous.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Acked-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -766,6 +766,7 @@ (%)
 		# try to put as many parameters as possible in PATH_INFO:
 		#   - project name
 		#   - action
+		#   - hash_parent or hash_parent_base:/file_parent
 		#   - hash or hash_base:/filename
 
 		# When the script is the root DirectoryIndex for the domain,
@@ -785,17 +786,36 @@ (%)
 			delete $params{'action'};
 		}
 
-		# Finally, we put either hash_base:/file_name or hash
+		# Next, we put hash_parent_base:/file_parent..hash_base:/file_name,
+		# stripping nonexistent or useless pieces
+		$href .= "/" if ($params{'hash_base'} || $params{'hash_parent_base'}
+			|| $params{'hash_parent'} || $params{'hash'});
 		if (defined $params{'hash_base'}) {
-			$href .= "/".esc_url($params{'hash_base'});
-			if (defined $params{'file_name'}) {
+			if (defined $params{'hash_parent_base'}) {
+				$href .= esc_url($params{'hash_parent_base'});
+				# skip the file_parent if it's the same as the file_name
+				delete $params{'file_parent'} if $params{'file_parent'} eq $params{'file_name'};
+				if (defined $params{'file_parent'} && $params{'file_parent'} !~ /\.\./) {
+					$href .= ":/".esc_url($params{'file_parent'});
+					delete $params{'file_parent'};
+				}
+				$href .= "..";
+				delete $params{'hash_parent'};
+				delete $params{'hash_parent_base'};
+			} elsif (defined $params{'hash_parent'}) {
+				$href .= esc_url($params{'hash_parent'}). "..";
+				delete $params{'hash_parent'};
+			}
+
+			$href .= esc_url($params{'hash_base'});
+			if (defined $params{'file_name'} && $params{'file_name'} !~ /\.\./) {
 				$href .= ":/".esc_url($params{'file_name'});
 				delete $params{'file_name'};
 			}
 			delete $params{'hash'};
 			delete $params{'hash_base'};
 		} elsif (defined $params{'hash'}) {
-			$href .= "/".esc_url($params{'hash'});
+			$href .= esc_url($params{'hash'});
 			delete $params{'hash'};
 		}
 	}