| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // |
| // This file defines the AsyncDNS class. AsyncDNS is used by processes resolve |
| // DNS addresses asynchronously. Currently, we use libevent's evdns mechanism |
| // underneath but its conceavable to use other implementations. Right now the |
| // only implementation is for http clients. |
| // |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #ifndef ASYNCDNS_H_ |
| #define ASYNCDNS_H_ |
| |
| #include <functional> |
| #include <vector> |
| #include "network/event_loop.h" |
| #include "basics/basics.h" |
| |
| // Forward declaration |
| struct evdns_base; |
| |
| /* |
| * AsyncDNS class definition |
| */ |
| class AsyncDNS { |
| public: |
| // User supplied callbacks are supplied with a status upon invokation. |
| enum Status { |
| // Uknown event happened. This in theory should not happen |
| OK = 0, |
| // A file descriptor is ready for read |
| NOTOK, |
| }; |
| |
| struct Result { |
| Status status_; |
| std::vector<sp_int32> addr_; |
| }; |
| |
| // Constructor/Destructor |
| explicit AsyncDNS(std::shared_ptr<EventLoop> eventLoop); |
| ~AsyncDNS(); |
| |
| // The main interface function. |
| // Resolve the address |
| sp_int32 Resolve(const sp_string& _address, VCallback<Result> _cb); |
| |
| //! Accessor function |
| struct evdns_base* dns() { |
| return dns_; |
| } |
| |
| private: |
| // The underlying dispatcher that we wrap around. |
| struct evdns_base* dns_; |
| }; |
| |
| #endif // ASYNCDNS_H_ |