private static boolean packageMatch(
     DescriptorProtos.FileDescriptorProto fileDescriptorProto, String packageName) {
   // Its a match iff
   // 1. package name specified as part of message type matches the package name of
   // FileDescriptorProto
   // 2. No package specified as part of message type and no package name specified in
   // FileDescriptorProto
   boolean packageMatch = false;
   if (packageName != null && packageName.equals(fileDescriptorProto.getPackage())) {
     packageMatch = true;
   } else if (packageName == null && !fileDescriptorProto.hasPackage()) {
     packageMatch = true;
   }
   return packageMatch;
 }