1 /* 2 * Copyright 2008 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef RTC_BASE_ASYNC_RESOLVER_H_ 12 #define RTC_BASE_ASYNC_RESOLVER_H_ 13 14 #if defined(WEBRTC_POSIX) 15 #include <sys/socket.h> 16 #elif WEBRTC_WIN 17 #include <winsock2.h> // NOLINT 18 #endif 19 20 #include <vector> 21 22 #include "api/sequence_checker.h" 23 #include "api/task_queue/pending_task_safety_flag.h" 24 #include "rtc_base/async_resolver_interface.h" 25 #include "rtc_base/event.h" 26 #include "rtc_base/ip_address.h" 27 #include "rtc_base/socket_address.h" 28 #include "rtc_base/system/no_unique_address.h" 29 #include "rtc_base/system/rtc_export.h" 30 #include "rtc_base/thread.h" 31 #include "rtc_base/thread_annotations.h" 32 33 namespace rtc { 34 35 // AsyncResolver will perform async DNS resolution, signaling the result on 36 // the SignalDone from AsyncResolverInterface when the operation completes. 37 // 38 // This class is thread-compatible, and all methods and destruction needs to 39 // happen from the same rtc::Thread, except for Destroy which is allowed to 40 // happen on another context provided it's not happening concurrently to another 41 // public API call, and is the last access to the object. 42 class RTC_EXPORT AsyncResolver : public AsyncResolverInterface { 43 public: 44 AsyncResolver(); 45 ~AsyncResolver() override; 46 47 void Start(const SocketAddress& addr) override; 48 void Start(const SocketAddress& addr, int family) override; 49 bool GetResolvedAddress(int family, SocketAddress* addr) const override; 50 int GetError() const override; 51 void Destroy(bool wait) override; 52 53 const std::vector<IPAddress>& addresses() const; 54 55 private: 56 // Fwd decl. 57 struct State; 58 59 void ResolveDone(std::vector<IPAddress> addresses, int error) 60 RTC_EXCLUSIVE_LOCKS_REQUIRED(sequence_checker_); 61 void MaybeSelfDestruct(); 62 63 SocketAddress addr_ RTC_GUARDED_BY(sequence_checker_); 64 std::vector<IPAddress> addresses_ RTC_GUARDED_BY(sequence_checker_); 65 int error_ RTC_GUARDED_BY(sequence_checker_); 66 bool recursion_check_ = 67 false; // Protects against SignalDone calling into Destroy. 68 bool destroy_called_ = false; 69 scoped_refptr<State> state_; 70 RTC_NO_UNIQUE_ADDRESS webrtc::SequenceChecker sequence_checker_; 71 }; 72 73 } // namespace rtc 74 75 #endif // RTC_BASE_ASYNC_RESOLVER_H_ 76