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/*
* Copyright (C) 2005-2018 Team Kodi
* This file is part of Kodi - https://kodi.tv
*
* SPDX-License-Identifier: GPL-2.0-or-later
* See LICENSES/README.md for more information.
*/
#pragma once
#include "threads/CriticalSection.h"
#include <atomic>
#include <vector>
class Observable;
class ObservableMessageJob;
typedef enum
{
ObservableMessageNone,
ObservableMessagePeripheralsChanged,
ObservableMessageSettingsChanged,
ObservableMessageButtonMapsChanged,
// Used for example when the subtitle alignment position change
ObservableMessagePositionChanged,
ObservableMessageGamePortsChanged,
ObservableMessageGameAgentsChanged,
} ObservableMessage;
class Observer
{
public:
Observer() = default;
virtual ~Observer() = default;
/*!
* @brief Process a message from an observable.
* @param obs The observable that sends the message.
* @param msg The message.
*/
virtual void Notify(const Observable &obs, const ObservableMessage msg) = 0;
};
class Observable
{
friend class ObservableMessageJob;
public:
Observable() = default;
virtual ~Observable() = default;
virtual Observable &operator=(const Observable &observable);
/*!
* @brief Register an observer.
* @param obs The observer to register.
*/
virtual void RegisterObserver(Observer *obs);
/*!
* @brief Unregister an observer.
* @param obs The observer to unregister.
*/
virtual void UnregisterObserver(Observer *obs);
/*!
* @brief Send a message to all observers when m_bObservableChanged is true.
* @param message The message to send.
*/
virtual void NotifyObservers(const ObservableMessage message = ObservableMessageNone);
/*!
* @brief Mark an observable changed.
* @param bSetTo True to mark the observable changed, false to mark it as unchanged.
*/
virtual void SetChanged(bool bSetTo = true);
/*!
* @brief Check whether this observable is being observed by an observer.
* @param obs The observer to check.
* @return True if this observable is being observed by the given observer, false otherwise.
*/
virtual bool IsObserving(const Observer &obs) const;
protected:
/*!
* @brief Send a message to all observer when m_bObservableChanged is true.
* @param obs The observer that sends the message.
* @param message The message to send.
*/
void SendMessage(const ObservableMessage message);
std::atomic<bool> m_bObservableChanged{false}; /*!< true when the observable is marked as changed, false otherwise */
std::vector<Observer *> m_observers; /*!< all observers */
mutable CCriticalSection m_obsCritSection; /*!< mutex */
};
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