Add ThreadBackgroundSleep helper class

openVulkanoCpp/Base/ThreadBackgroundSleep.cpp

@@ -0,0 +1,47 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include "ThreadBackgroundSleep.hpp"
+#include "Logger.hpp"
+#include "AppEvents.hpp"
+
+namespace openVulkanoCpp
+{
+	ThreadBackgroundSleep ThreadBackgroundSleep::INSTANCE;
+
+	ThreadBackgroundSleep::ThreadBackgroundSleep()
+	{
+		m_resignHandler = AppEvents::OnWillResignActive += [this]() { m_inBackground = true;  };
+		m_resumeHandler = AppEvents::OnDidBecomeActive  += [this]() { Resume(); };
+	}
+
+	ThreadBackgroundSleep::~ThreadBackgroundSleep()
+	{
+		AppEvents::OnWillResignActive -= m_resignHandler;
+		AppEvents::OnDidBecomeActive -= m_resumeHandler;
+		Resume();
+	}
+
+	void ThreadBackgroundSleep::Resume()
+	{
+		{
+			std::unique_lock lock(m_mutex);
+			m_inBackground = false;
+		}
+		m_condVar.notify_all();
+	}
+
+	void ThreadBackgroundSleep::CheckForBackground(std::string_view taskName)
+	{
+		if (m_inBackground)
+		{
+			Logger::MANAGER->info("Sleep {}, because app has been sent to background.", taskName);
+			std::unique_lock l(m_mutex);
+			m_condVar.wait(l, [this]{ return !m_inBackground; });
+			Logger::MANAGER->info("Resume {}, app is no longer in background.", taskName);
+		}
+	}
+}

openVulkanoCpp/Base/ThreadBackgroundSleep.hpp

@@ -0,0 +1,34 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <condition_variable>
+#include <mutex>
+#include <string_view>
+
+namespace openVulkanoCpp
+{
+	class IEventHandler;
+
+	class ThreadBackgroundSleep final
+	{
+		std::mutex m_mutex;
+		std::condition_variable m_condVar;
+		bool m_inBackground = false;
+		IEventHandler* m_resignHandler = nullptr;
+		IEventHandler* m_resumeHandler = nullptr;
+
+	public:
+		static ThreadBackgroundSleep INSTANCE;
+
+		ThreadBackgroundSleep();
+
+		~ThreadBackgroundSleep();
+
+		void Resume();
+
+		void CheckForBackground(std::string_view taskName);
+	};
+}