void instance::write(buffer_type& buf,
message_type operation,
uint32_t* payload_len,
uint64_t operation_data,
const node_id& source_node,
const node_id& dest_node,
actor_id source_actor,
actor_id dest_actor,
payload_writer* pw) {
if (! pw) {
binary_serializer bs{std::back_inserter(buf), &get_namespace()};
source_node.serialize(bs);
dest_node.serialize(bs);
bs.write(source_actor)
.write(dest_actor)
.write(uint32_t{0})
.write(static_cast<uint32_t>(operation))
.write(operation_data);
} else {
// reserve space in the buffer to write the payload later on
auto wr_pos = static_cast<ptrdiff_t>(buf.size());
char placeholder[basp::header_size];
buf.insert(buf.end(), std::begin(placeholder), std::end(placeholder));
auto pl_pos = buf.size();
{ // lifetime scope of first serializer (write payload)
binary_serializer bs1{std::back_inserter(buf), &get_namespace()};
(*pw)(bs1);
}
// write broker message to the reserved space
binary_serializer bs2{buf.begin() + wr_pos, &get_namespace()};
auto plen = static_cast<uint32_t>(buf.size() - pl_pos);
source_node.serialize(bs2);
dest_node.serialize(bs2);
bs2.write(source_actor)
.write(dest_actor)
.write(plen)
.write(static_cast<uint32_t>(operation))
.write(operation_data);
if (payload_len)
*payload_len = plen;
}
}
