// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef DEVICE_REQUEST_H
#define DEVICE_REQUEST_H

#include "magma_util/macros.h"
#include "magma_util/status.h"
#include "platform_event.h"
#include <memory>

template <class Processor> class DeviceRequest {
public:
    virtual ~DeviceRequest() {}

    class Reply {
    public:
        Reply() : status_(MAGMA_STATUS_OK), event_(magma::PlatformEvent::Create())
        {
            DASSERT(event_);
        }

        void Signal(magma::Status status)
        {
            status_ = status;
            event_->Signal();
        }

        magma::Status Wait()
        {
            event_->Wait();
            return status_;
        }

    private:
        magma::Status status_;
        std::unique_ptr<magma::PlatformEvent> event_;
    };

    std::shared_ptr<Reply> GetReply()
    {
        if (!reply_)
            reply_ = std::shared_ptr<Reply>(new Reply());
        return reply_;
    }

    void ProcessAndReply(Processor* processor)
    {
        magma::Status status = Process(processor);

        if (reply_)
            reply_->Signal(status);
    }

protected:
    virtual magma::Status Process(Processor* processor) { return MAGMA_STATUS_OK; }

private:
    std::shared_ptr<Reply> reply_;
};

#endif