/*
 * Copyright 2011, Ingo Weinhold, ingo_weinhold@gmx.de.
 * Distributed under the terms of the MIT License.
 */
#ifndef _KERNEL_DPC_H
#define _KERNEL_DPC_H


#include <sys/cdefs.h>

#include <KernelExport.h>

#include <util/DoublyLinkedList.h>

#include <condition_variable.h>


namespace BKernel {


class DPCQueue;


class DPCCallback : public DoublyLinkedListLinkImpl<DPCCallback> {
public:
                                                                DPCCallback();
        virtual                                         ~DPCCallback();

        virtual void                            DoDPC(DPCQueue* queue) = 0;

private:
                        friend class DPCQueue;

private:
                        DPCQueue*                       fInQueue;
};


class FunctionDPCCallback : public DPCCallback {
public:
                                                                FunctionDPCCallback(DPCQueue* owner);

                        void                            SetTo(void (*function)(void*), void* argument);

        virtual void                            DoDPC(DPCQueue* queue);

private:
                        DPCQueue*                       fOwner;
                        void                            (*fFunction)(void*);
                        void*                           fArgument;
};


class DPCQueue {
public:
                                                                DPCQueue();
                                                                ~DPCQueue();

        static  DPCQueue*                       DefaultQueue(int priority);

                        status_t                        Init(const char* name, int32 priority,
                                                                        uint32 reservedSlots);
                        void                            Close(bool cancelPending);

                        status_t                        Add(DPCCallback* callback);
                        status_t                        Add(void (*function)(void*), void* argument);
                        bool                            Cancel(DPCCallback* callback);

                        thread_id                       Thread() const
                                                                        { return fThreadID; }

public:
                        // conceptually package private
                        void                            Recycle(FunctionDPCCallback* callback);

private:
                        typedef DoublyLinkedList<DPCCallback> CallbackList;

private:
        static  status_t                        _ThreadEntry(void* data);
                        status_t                        _Thread();

                        bool                            _IsClosed() const
                                                                        { return fThreadID < 0; }

private:
                        spinlock                        fLock;
                        thread_id                       fThreadID;
                        CallbackList            fCallbacks;
                        CallbackList            fUnusedFunctionCallbacks;
                        ConditionVariable       fPendingCallbacksCondition;
                        DPCCallback*            fCallbackInProgress;
                        ConditionVariable*      fCallbackDoneCondition;
};


}       // namespace BKernel


using BKernel::DPCCallback;
using BKernel::DPCQueue;
using BKernel::FunctionDPCCallback;


__BEGIN_DECLS

void            dpc_init();

__END_DECLS


#endif  // _KERNEL_DPC_H