use boost::async instead of std::async as ~boost::async is nonblocking

configure.ac

@@ -143,6 +143,17 @@ PKG_CHECK_MODULES([ICU], [icu-uc], [
 	)
 ], [[]])
 
+dnl =============================
+dnl = checking for boost.thread =
+dnl =============================
+AC_DEFINE([BOOST_THREAD_VERSION], [3], [require boost.thread v3])
+AC_CHECK_HEADERS([boost/thread.hpp], ,
+	AC_MSG_ERROR([boost/thread.hpp is missing or your boost version is too old (boost.thread v3 is required)])
+)
+AC_CHECK_LIB(boost_thread$BOOST_LIB_SUFFIX, main, LIBS="$LIBS -lboost_thread$BOOST_LIB_SUFFIX",
+	AC_MSG_ERROR([no boost.thread library found])
+)
+
 dnl ================================
 dnl = checking for various headers =
 dnl ================================

src/lastfm.cpp

@@ -52,11 +52,8 @@ std::wstring Lastfm::title()
 
 void Lastfm::update()
 {
-	if (m_worker.valid()
-	    && m_worker.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
-	{
+	if (m_worker.valid() && m_worker.is_ready())
 		getResult();
-	}
 }
 
 void Lastfm::switchTo()
@@ -85,5 +82,5 @@ void Lastfm::getResult()
 	w.flush();
 	w.refresh();
 	// reset m_worker so it's no longer valid
-	m_worker = std::future<LastFm::Service::Result>();
+	m_worker = boost::BOOST_THREAD_FUTURE<LastFm::Service::Result>();
 }

src/lastfm.h

@@ -23,7 +23,7 @@
 
 #include "config.h"
 
-#include <future>
+#include <boost/thread/future.hpp>
 #include <memory>
 
 #include "interfaces.h"
@@ -55,8 +55,9 @@ struct Lastfm: Screen<NC::Scrollpad>, Tabbable
 			return;
 
 		m_service = std::shared_ptr<ServiceT>(service);
-		m_worker = std::async(std::launch::async,
-		                      std::bind(&LastFm::Service::fetch, m_service));
+		m_worker = boost::async(
+			boost::launch::async,
+			std::bind(&LastFm::Service::fetch, m_service));
 
 		w.clear();
 		w << "Fetching information...";
@@ -70,7 +71,7 @@ private:
 	std::wstring m_title;
 	
 	std::shared_ptr<LastFm::Service> m_service;
-	std::future<LastFm::Service::Result> m_worker;
+	boost::BOOST_THREAD_FUTURE<LastFm::Service::Result> m_worker;
 };
 
 extern Lastfm *myLastfm;

src/lyrics.cpp

@@ -25,6 +25,7 @@
 #include <cerrno>
 #include <cstring>
 #include <fstream>
+#include <thread>
 
 #include "browser.h"
 #include "charset.h"
@@ -213,7 +214,7 @@ void Lyrics::update()
 			m_refresh_window = true;
 		}
 
-		if (m_worker.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
+		if (m_worker.is_ready())
 		{
 			auto lyrics = m_worker.get();
 			if (lyrics)
@@ -279,8 +280,8 @@ void Lyrics::fetch(const MPD::Song &s)
 		else
 		{
 			m_shared_buffer = std::make_shared<Shared<NC::Buffer>>();
-			m_worker = std::async(
-				std::launch::async,
+			m_worker = boost::async(
+				boost::launch::async,
 				std::bind(downloadLyrics, m_song, m_shared_buffer, m_fetcher));
 		}
 	}
@@ -422,5 +423,5 @@ boost::optional<std::string> Lyrics::tryTakeConsumerMessage()
 void Lyrics::clearWorker()
 {
 	m_shared_buffer.reset();
-	m_worker = std::future<boost::optional<std::string>>();
+	m_worker = boost::BOOST_THREAD_FUTURE<boost::optional<std::string>>();
 }

src/lyrics.h

@@ -22,7 +22,7 @@
 #define NCMPCPP_LYRICS_H
 
 #include <boost/optional.hpp>
-#include <future>
+#include <boost/thread/future.hpp>
 #include <memory>
 #include <queue>
 
@@ -96,7 +96,7 @@ private:
 
 	MPD::Song m_song;
 	LyricsFetcher *m_fetcher;
-	std::future<boost::optional<std::string>> m_worker;
+	boost::BOOST_THREAD_FUTURE<boost::optional<std::string>> m_worker;
 
 	Shared<ConsumerState> m_consumer_state;
 };