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);
+		}
+	}
+}