MotionManager.h

Go to the documentation of this file.

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_DEVICES_IOS_MOTION_MANAGER_H
#define META_OCEAN_DEVICES_IOS_MOTION_MANAGER_H
 
#include "ocean/devices/ios/IOS.h"
 
#include "ocean/base/Callback.h"
#include "ocean/base/Lock.h"
#include "ocean/base/Singleton.h"
 
#include <CoreMotion/CoreMotion.h>
 
namespace Ocean
{
 
namespace Devices
{
 
namespace IOS
{
 
/**
 * This class implements a simple wrapper for the CMMotionManager object as an application must not create more than one instance of a CMMotionManager object.
 * This class is implemented as a singleton and the actual CMMotionManager object can be set explicitly (if already existing in the application), or will be created automatically.<br>
 * The manager is thread-safe.
 * @ingroup devicesios
 */
class OCEAN_DEVICES_IOS_EXPORT MotionManager : public Singleton<MotionManager>
{
    friend class Singleton<MotionManager>;
 
    public:
 
        /**
         * Definition of a listener id for a registered callbacks.
         */
        typedef unsigned int ListenerId;
 
        /**
         * Definition of a callback function to subscribe for new device motion samples.
         */
        typedef Callback<void, CMDeviceMotion*> DeviceMotionCallback;
 
    protected:
 
        /**
         * Type of an unordered map mapping listener ids to callback functions.
         */
        typedef std::unordered_map<ListenerId, DeviceMotionCallback> DeviceMotionListenerMap;
 
    public:
 
        /**
         * Returns the instance of the CMMotionManager object hold by this singleton.
         * In the case the object hasn't been set explicitly an object will be created the first time this function is called.
         * @return The CMMotionManager object
         * @see setObject();
         */
        CMMotionManager* object();
 
        /**
         * Sets the instance of the CMMotionManager object explicitly as the application holds the instance already.
         * Do not call this function twice.
         * @param object The CMMotionManager object to be set explicitly, must be valid
         * @return True, if this singleton does not hold an own object already and if the provided object is valids
         */
        bool setObject(CMMotionManager* object);
 
        /**
         * Register a new listener.
         * @param callback Callback function that occurs each time a new DeviceMotion sample is provided
         * @return Unique id for the registered callback
         */
        ListenerId addListener(const DeviceMotionCallback& callback);
 
        /**
         * Unregister a given listener.
         * @param listenerId Id returned from addListener, must be valid
         */
        void removeListener(const ListenerId listenerId);
 
        /**
         * Returns an invalid listener id.
         * @return Invalid listener id
         */
        static constexpr inline ListenerId invalidListenerId();
 
    protected:
 
        /**
         * Protected default constructor.
         */
        MotionManager() = default;
 
        /**
         * Internally starts the main DeviceMotion callback with CMMotionMap.
         */
        void start();
 
    protected:
 
        /// The instance of the CMMotionManager object this singleton is responsible for.
        CMMotionManager* motionManager_ = nullptr;
 
        /// Map storing the set of registered listeners.
        DeviceMotionListenerMap deviceMotionListenerMap_;
 
        /// Counter used to produce a new id when addListener is called.
        unsigned int nextListenerId_ = invalidListenerId();
 
        /// The manager's lock.
        Lock lock_;
};
 
inline constexpr MotionManager::ListenerId MotionManager::invalidListenerId()
{
    return 0u;
}
 
}
 
}
 
}
 
#endif // META_OCEAN_DEVICES_IOS_MOTION_MANAGER_H