message: refactor: net: avoid duplicate map lookups to `mapLocalHost`
diff: @@ -194,8 +194,8 @@ CAddress GetLocalAddress(const CNetAddr *paddrPeer, ServiceFlags nLocalServices)
  static int GetnScore(const CService& addr)
  {
  LOCK(cs_mapLocalHost);
  - if (mapLocalHost.count(addr) == 0) return 0;
  - return mapLocalHost[addr].nScore;
  + const auto it = mapLocalHost.find(addr);
  + return (it != mapLocalHost.end()) ? it->second.nScore : 0;
  }
  // Is our peer's addrLocal potentially useful as an external IP source?
  @@ -247,10 +247,10 @@ bool AddLocal(const CService& addr, int nScore)
  {
  LOCK(cs_mapLocalHost);
  - bool fAlready = mapLocalHost.count(addr) > 0;
  - LocalServiceInfo &info = mapLocalHost[addr];
  - if (!fAlready || nScore >= info.nScore) {
  - info.nScore = nScore + (fAlready ? 1 : 0);
  + const auto [it, is_newly_added] = mapLocalHost.emplace(addr, LocalServiceInfo());
  + LocalServiceInfo &info = it->second;
  + if (is_newly_added || nScore >= info.nScore) {
  + info.nScore = nScore + (is_newly_added ? 0 : 1);
  info.nPort = addr.GetPort();
  }
  }
  @@ -291,13 +291,11 @@ bool IsReachable(const CNetAddr &addr)
  /** vote for a local address */
  bool SeenLocal(const CService& addr)
  -{
  {
  LOCK(cs_mapLocalHost);
  - if (mapLocalHost.count(addr) == 0)
  - return false;
  - mapLocalHost[addr].nScore++;
  - }
  + const auto it = mapLocalHost.find(addr);
  + if (it == mapLocalHost.end()) return false;
  + ++it->second.nScore;
  return true;
  }
  