VideoCommon: Clean up and eliminate the mutex in AsyncRequests using WaitableSPSCQueue.

Source/Core/VideoCommon/AsyncRequests.cpp

@@ -3,8 +3,6 @@
 
 #include "VideoCommon/AsyncRequests.h"
 
-#include <mutex>
-
 #include "Core/System.h"
 
 #include "VideoCommon/Fifo.h"
@@ -16,33 +14,25 @@ AsyncRequests AsyncRequests::s_singleton;
 
 AsyncRequests::AsyncRequests() = default;
 
-void AsyncRequests::PullEventsInternal()
+void AsyncRequests::PullEvents()
 {
+  if (m_queue.Empty())
+    return;
+
   // This is only called if the queue isn't empty.
   // So just flush the pipeline to get accurate results.
   g_vertex_manager->Flush();
 
-  std::unique_lock<std::mutex> lock(m_mutex);
-  m_empty.Set();
-
-  while (!m_queue.empty())
+  while (!m_queue.Empty())
   {
-    Event e = std::move(m_queue.front());
-    lock.unlock();
-    std::invoke(e);
-    lock.lock();
-
-    m_queue.pop();
+    std::invoke(std::move(m_queue.Front()));
+    m_queue.Pop();
   }
-
-  m_cond.notify_one();
 }
 
 void AsyncRequests::QueueEvent(Event&& event)
 {
-  m_empty.Clear();
-
-  m_queue.push(std::move(event));
+  m_queue.Push(std::move(event));
 
   auto& system = Core::System::GetInstance();
   system.GetFifo().RunGpu();
@@ -50,12 +40,10 @@ void AsyncRequests::QueueEvent(Event&& event)
 
 void AsyncRequests::WaitForEmptyQueue()
 {
-  std::unique_lock<std::mutex> lock(m_mutex);
-  m_cond.wait(lock, [this] { return m_queue.empty(); });
+  m_queue.WaitForEmpty();
 }
 
 void AsyncRequests::SetPassthrough(bool enable)
 {
-  std::unique_lock<std::mutex> lock(m_mutex);
   m_passthrough = enable;
 }