VideoCommon: use a new async event system for efb access

Source/Core/VideoCommon/AsyncRequests.cpp

@@ -0,0 +1,88 @@
+#include "VideoCommon/AsyncRequests.h"
+#include "VideoCommon/RenderBase.h"
+
+AsyncRequests AsyncRequests::s_singleton;
+
+AsyncRequests::AsyncRequests()
+: m_enable(false)
+{
+}
+
+void AsyncRequests::PullEventsInternal()
+{
+	std::unique_lock<std::mutex> lock(m_mutex);
+	m_empty.store(true);
+
+	while (!m_queue.empty())
+	{
+		const Event& e = m_queue.front();
+
+		lock.unlock();
+		HandleEvent(e);
+		lock.lock();
+
+		m_queue.pop();
+	}
+
+	if (m_wake_me_up_again)
+	{
+		m_wake_me_up_again = false;
+		m_cond.notify_all();
+	}
+}
+
+void AsyncRequests::PushEvent(const AsyncRequests::Event& event, bool blocking)
+{
+	std::unique_lock<std::mutex> lock(m_mutex);
+	m_empty.store(false);
+	m_wake_me_up_again |= blocking;
+
+	if (!m_enable)
+		return;
+
+	m_queue.push(event);
+
+	if (blocking)
+	{
+		m_cond.wait(lock, [this]{return m_queue.empty();});
+	}
+}
+
+void AsyncRequests::SetEnable(bool enable)
+{
+	std::unique_lock<std::mutex> lock(m_mutex);
+	m_enable = enable;
+
+	if (!enable)
+	{
+		// flush the queue on disabling
+		while (!m_queue.empty())
+			m_queue.pop();
+		if (m_wake_me_up_again)
+			m_cond.notify_all();
+	}
+}
+
+void AsyncRequests::HandleEvent(const AsyncRequests::Event& e)
+{
+	switch (e.type)
+	{
+		case Event::EFB_POKE_COLOR:
+			g_renderer->AccessEFB(POKE_COLOR, e.efb_poke.x, e.efb_poke.y, e.efb_poke.data);
+			break;
+
+		case Event::EFB_POKE_Z:
+			g_renderer->AccessEFB(POKE_Z, e.efb_poke.x, e.efb_poke.y, e.efb_poke.data);
+			break;
+
+		case Event::EFB_PEEK_COLOR:
+			*e.efb_peek.data = g_renderer->AccessEFB(PEEK_COLOR, e.efb_peek.x, e.efb_peek.y, 0);
+			break;
+
+		case Event::EFB_PEEK_Z:
+			*e.efb_peek.data = g_renderer->AccessEFB(PEEK_Z, e.efb_peek.x, e.efb_peek.y, 0);
+			break;
+
+	}
+}
+