replace poll thread with async future

common/SoapyMDNSEndpointAvahi.cpp

@@ -14,7 +14,7 @@
 #include <cstdlib> //atoi
 #include <cstdio> //snprintf
 #include <mutex>
-#include <thread>
+#include <future>
 #include <tuple>
 #include <map>
 
@@ -48,7 +48,7 @@ struct SoapyMDNSEndpointData
  SoapyMDNSEndpointData(void);
  ~SoapyMDNSEndpointData(void);
  AvahiSimplePoll *simplePoll;
- std::thread *pollThread;
+ std::shared_future<int> pollTask;
  AvahiClient *client;
  AvahiEntryGroup *group;
  AvahiServiceBrowser *browser;
@@ -83,7 +83,6 @@ static void clientCallback(AvahiClient *c, AvahiClientState state, void *userdat
 
 SoapyMDNSEndpointData::SoapyMDNSEndpointData(void):
  simplePoll(nullptr),
- pollThread(nullptr),
  client(nullptr),
  group(nullptr),
  browser(nullptr),
@@ -109,11 +108,7 @@ SoapyMDNSEndpointData::SoapyMDNSEndpointData(void):
 SoapyMDNSEndpointData::~SoapyMDNSEndpointData(void)
 {
  if (simplePoll != nullptr) avahi_simple_poll_quit(simplePoll);
- if (pollThread != nullptr)
- {
- pollThread->join();
- delete pollThread;
- }
+ if (pollTask.valid()) pollTask.wait();
  if (browser != nullptr) avahi_service_browser_free(browser);
  if (group != nullptr) avahi_entry_group_free(group);
  if (client != nullptr) avahi_client_free(client);
@@ -234,7 +229,7 @@ void SoapyMDNSEndpoint::registerService(const std::string &uuid, const std::stri
  return;
  }
 
- _impl->pollThread = new std::thread(&avahi_simple_poll_loop, _impl->simplePoll);
+ _impl->pollTask = std::async(std::launch::async, &avahi_simple_poll_loop, _impl->simplePoll);
 }
 
 /***********************************************************************
@@ -255,9 +250,9 @@ void SoapyMDNSEndpointData::add_result(
  const auto ipVer = avahiProtocolToIpVer(protocol);
  const auto addr = (protocol == AVAHI_PROTO_INET6)? (host + "%" + std::to_string(interface)):host;
  const auto serverURL = SoapyURL("tcp", addr, std::to_string(port)).toString();
- SoapySDR::logf(SOAPY_SDR_DEBUG, "SoapyMDNSEndpoint discovered %s [%s] IPv%d", serverURL.c_str(), uuid.c_str(), ipVer);
- auto key = SoapyMDNSEndpointData::ResultKey(interface, protocol, name, type, domain);
- auto value = SoapyMDNSEndpointData::ResultValue(uuid, ipVer, serverURL);
+ SoapySDR::logf(SOAPY_SDR_DEBUG, "SoapyMDNS discovered %s [%s] IPv%d", serverURL.c_str(), uuid.c_str(), ipVer);
+ auto key = ResultKey(interface, protocol, name, type, domain);
+ auto value = ResultValue(uuid, ipVer, serverURL);
  std::lock_guard<std::recursive_mutex> l(mutex);
  results[key] = value;
 }
@@ -269,7 +264,7 @@ void SoapyMDNSEndpointData::remove_result(
  const std::string &type,
  const std::string &domain)
 {
- auto key = SoapyMDNSEndpointData::ResultKey(interface, protocol, name, type, domain);
+ auto key = ResultKey(interface, protocol, name, type, domain);
  std::string uuid;
  int ipVer;
  std::string serverURL;
@@ -280,7 +275,7 @@ void SoapyMDNSEndpointData::remove_result(
  std::tie(uuid, ipVer, serverURL) = it->second;
  results.erase(it);
  }
- SoapySDR::logf(SOAPY_SDR_DEBUG, "SoapyMDNSEndpoint removed %s [%s] IPv%d", serverURL.c_str(), uuid.c_str(), ipVer);
+ SoapySDR::logf(SOAPY_SDR_DEBUG, "SoapyMDNS removed %s [%s] IPv%d", serverURL.c_str(), uuid.c_str(), ipVer);
 }
 
 static void resolverCallback(
@@ -408,7 +403,7 @@ std::map<std::string, std::map<int, std::string>> SoapyMDNSEndpoint::getServerUR
  }
 
  //run in background for subsequent calls
- _impl->pollThread = new std::thread(&avahi_simple_poll_loop, _impl->simplePoll);
+ _impl->pollTask = std::async(std::launch::async, &avahi_simple_poll_loop, _impl->simplePoll);
 
  getResults:
  std::map<std::string, std::map<int, std::string>> uuidToUrl;