+
+ # next, handle the 'parent' part, if present
+ if (defined $parentrefname) {
+ # a missing pathspec defaults to the 'current' filename, allowing e.g.
+ # someproject/blobdiff/oldrev..newrev:/filename
+ if ($parentpathname) {
+ $parentpathname =~ s,^/+,,;
+ $parentpathname =~ s,/$,,;
+ $input_params{'file_parent'} ||= $parentpathname;
+ } else {
+ $input_params{'file_parent'} ||= $input_params{'file_name'};
+ }
+ # we assume that hash_parent_base is wanted if a path was specified,
+ # or if the action wants hash_base instead of hash
+ if (defined $input_params{'file_parent'} ||
+ grep { $_ eq $input_params{'action'} } @wants_base) {
+ $input_params{'hash_parent_base'} ||= $parentrefname;
+ } else {
+ $input_params{'hash_parent'} ||= $parentrefname;
+ }
+ }