add request topic cache; refactor req/rep center.

lichao

2021-04-02 dc12826dd61ce18fac3a9561c5843d30a0cf9660

 src/reqrep.cpp

@@ -155,8 +155,7 @@

bool SocketRequest::QueryRPCTopic(const std::string &topic, bhome::msg::BHAddress &addr, const int timeout_ms)
{
   if (tmp_cache_.first == topic) {
      addr = tmp_cache_.second;
   if (topic_cache_.Find(topic, addr)) {
      return true;
   }

@@ -167,9 +166,12 @@
         DataProcQueryTopicReply reply;
         if (reply.ParseFromString(result.body())) {
            addr = reply.address();
            tmp_cache_.first = topic;
            tmp_cache_.second = addr;
            return !addr.mq_id().empty();
            if (addr.mq_id().empty()) {
               return false;
            } else {
               topic_cache_.Update(topic, addr);
               return true;
            }
         }
      }
   } else {