Scheduler.h

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/*
 * 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_BASE_SCHEDULER_H
#define META_OCEAN_BASE_SCHEDULER_H
 
#include "ocean/base/Base.h"
#include "ocean/base/Callback.h"
#include "ocean/base/Singleton.h"
#include "ocean/base/Thread.h"
 
#include <map>
 
namespace Ocean
{
 
/**
 * This class represents a round robin scheduler.
 * The scheduler is based on one single thread and executes all registered functions in a round robin manner.<br>
 * The registered functions are called with high frequency (e.g., each 10-50 ms).<br>
 * A registered function should return immediately so that a high call frequency for all registered function can be ensured.
 * @see ThreadPool, TaskQueue.
 * @ingroup base
 */
class OCEAN_BASE_EXPORT Scheduler :
    public Singleton<Scheduler>,
    protected Thread
{
    friend class Singleton<Scheduler>;
 
    public:
 
        /**
         * Definition of a callback function.
         */
        using Callback = Ocean::Callback<void>;
 
    private:
 
        /**
         * Definition of a callback pair holding a callback function and an active flag.
         */
        using Callbacks = ConcurrentCallbacks<Callback>;
 
    public:
 
        /**
         * Registers a scheduler function.
         * Each registered function must be unregistered by the caller if the scheduler event is not needed anymore.
         * @param callback Callback function to register
         * @see unregisterFunction().
         */
        void registerFunction(const Callback& callback);
 
        /**
         * Unregisters a scheduler function.
         * This function may be called from a registered scheduler function.
         * @param callback Callback function to unregister
         * @see registerFunction().
         */
        void unregisterFunction(const Callback& callback);
 
    protected:
 
        /**
         * Creates a new scheduler.
         */
        Scheduler();
 
        /**
         * Destructs a scheduler.
         */
        virtual ~Scheduler();
 
        /**
         * Derived thread run function.
         */
        virtual void threadRun();
 
    protected:
 
        /// Scheduler callbacks.
        Callbacks callbacks;
};
 
}
 
#endif // META_OCEAN_BASE_SCHEDULER_H