Add a service to announce multiplayer rooms to web service; Add the abiltiy to receive a list of all announced rooms from web service

src/core/announce_multiplayer_session.h

@@ -0,0 +1,71 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <atomic>
+#include <functional>
+#include <memory>
+#include <set>
+#include <thread>
+#include "common/announce_multiplayer_room.h"
+#include "common/common_types.h"
+
+namespace Core {
+
+/**
+ * Instruments AnnounceMultiplayerRoom::Backend.
+ * Creates a thread that regularly updates the room information and submits them
+ * An async get of room information is also possible
+ */
+class AnnounceMultiplayerSession : NonCopyable {
+public:
+    AnnounceMultiplayerSession();
+    ~AnnounceMultiplayerSession();
+
+    /**
+     * Allows to bind a function that will get called if the announce encounters an error
+     * @param function The function that gets called
+     * @return A handle that can be used the unbind the function
+     */
+    std::shared_ptr<std::function<void(const Common::WebResult&)>> BindErrorCallback(
+        std::function<void(const Common::WebResult&)> function);
+
+    /**
+     * Unbind a function from the error callbacks
+     * @param handle The handle for the function that should get unbind
+     */
+    void UnbindErrorCallback(std::shared_ptr<std::function<void(const Common::WebResult&)>> handle);
+
+    /**
+     * Starts the announce of a room to web services
+     */
+    void Start();
+
+    /**
+     * Stops the announce to web services
+     */
+    void Stop();
+
+    /**
+     *  Returns a list of all room information the backend got
+     * @param func A function that gets executed when the async get finished, e.g. a signal
+     * @return a list of rooms received from the web service
+     */
+    std::future<AnnounceMultiplayerRoom::RoomList> GetRoomList(std::function<void()> func);
+
+private:
+    std::atomic<bool> announce{false};
+    std::atomic<bool> finished{true};
+    std::mutex callback_mutex;
+    std::set<std::shared_ptr<std::function<void(const Common::WebResult&)>>> error_callbacks;
+    std::unique_ptr<std::thread> announce_multiplayer_thread;
+
+    std::unique_ptr<AnnounceMultiplayerRoom::Backend>
+        backend; ///< Backend interface that logs fields
+
+    void AnnounceMultiplayerLoop();
+};
+
+} // namespace Core