New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/drape_frontend/message_acceptor.hpp

@@ -0,0 +1,49 @@
+#pragma once
+
+#include "drape_frontend/message_queue.hpp"
+
+#include "drape/pointers.hpp"
+
+#include <atomic>
+#include <mutex>
+#include <functional>
+
+namespace df
+{
+class Message;
+
+class MessageAcceptor
+{
+protected:
+  MessageAcceptor();
+  virtual ~MessageAcceptor() = default;
+
+  virtual void AcceptMessage(ref_ptr<Message> message) = 0;
+
+  /// Must be called by subclass on message target thread
+  bool ProcessSingleMessage(bool waitForMessage = true);
+
+  void CancelMessageWaiting();
+
+  void CloseQueue();
+
+  bool IsInInfinityWaiting() const;
+
+#ifdef DEBUG_MESSAGE_QUEUE
+  bool IsQueueEmpty() const;
+  size_t GetQueueSize() const;
+#endif
+
+  void EnableMessageFiltering(MessageQueue::FilterMessageFn && filter);
+  void DisableMessageFiltering();
+  void InstantMessageFilter(MessageQueue::FilterMessageFn && filter);
+
+private:
+  friend class ThreadsCommutator;
+
+  void PostMessage(drape_ptr<Message> && message, MessagePriority priority);
+
+  MessageQueue m_messageQueue;
+  std::atomic<bool> m_infinityWaiting;
+};
+}  // namespace df