IXWebSocket/ixwebsocket/IXDNSLookup.h

76 lines
2.3 KiB
C++

/*
* IXDNSLookup.h
* Author: Benjamin Sergeant
* Copyright (c) 2018 Machine Zone, Inc. All rights reserved.
*
* Resolve a hostname+port to a struct addrinfo obtained with getaddrinfo
* Does this in a background thread so that it can be cancelled, since
* getaddrinfo is a blocking call, and we don't want to block the main thread on Mobile.
*/
#pragma once
#include "IXCancellationRequest.h"
#include <atomic>
#include <condition_variable>
#include <set>
#include <string>
#include <thread>
#include <memory>
struct addrinfo;
namespace ix
{
class DNSLookup : public std::enable_shared_from_this<DNSLookup>
{
public:
DNSLookup(const std::string& hostname, int port, int64_t wait = DNSLookup::kDefaultWait);
~DNSLookup() = default;
struct addrinfo* resolve(std::string& errMsg,
const CancellationRequest& isCancellationRequested,
bool blocking = false);
private:
struct addrinfo* resolveAsync(std::string& errMsg,
const CancellationRequest& isCancellationRequested);
struct addrinfo* resolveBlocking(std::string& errMsg,
const CancellationRequest& isCancellationRequested);
static struct addrinfo* getAddrInfo(const std::string& hostname,
int port,
std::string& errMsg);
void run(std::weak_ptr<DNSLookup> self, const std::string& hostname, int port); // thread runner
void setHostname(const std::string& hostname);
const std::string& getHostname();
void setErrMsg(const std::string& errMsg);
const std::string& getErrMsg();
void setRes(struct addrinfo* addr);
struct addrinfo* getRes();
std::string _hostname;
std::mutex _hostnameMutex;
int _port;
int64_t _wait;
struct addrinfo* _res;
std::mutex _resMutex;
std::string _errMsg;
std::mutex _errMsgMutex;
std::atomic<bool> _done;
std::thread _thread;
std::condition_variable _condition;
std::mutex _conditionVariableMutex;
const static int64_t kDefaultWait;
};
} // namespace ix