frame_mailbox.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright The KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef RHI_FRAME_MAILBOX_H
#define RHI_FRAME_MAILBOX_H
 
#include <rhi/frame_packet.h>
 
#include <atomic>
#include <memory>
 
 
namespace KIGFX
{

class FRAME_MAILBOX
{
public:
    FRAME_MAILBOX() = default;
 
    ~FRAME_MAILBOX()
    {
        delete m_pending.load( std::memory_order_acquire );
    }
 
    FRAME_MAILBOX( const FRAME_MAILBOX& ) = delete;
    FRAME_MAILBOX& operator=( const FRAME_MAILBOX& ) = delete;

    std::unique_ptr<FRAME_PACKET> Submit( std::unique_ptr<FRAME_PACKET> aPacket )
    {
        if( aPacket )
        {
            aPacket->bufferGeneration = std::min( aPacket->staticDrawDesc.bufferGeneration,
                                                  aPacket->dynamicDrawDesc.bufferGeneration );
        }
 
        if( aPacket )
            m_pendingInputSerial.store( aPacket->inputSerial, std::memory_order_release );
 
        FRAME_PACKET* old = m_pending.exchange( aPacket.release(), std::memory_order_acq_rel );
        return std::unique_ptr<FRAME_PACKET>( old );
    }

    std::unique_ptr<FRAME_PACKET> Load()
    {
        std::unique_ptr<FRAME_PACKET> packet( m_pending.exchange( nullptr, std::memory_order_acq_rel ) );

        if( packet )
            m_consumedGeneration.store( packet->bufferGeneration, std::memory_order_release );
 
        return packet;
    }

    uint64_t ConsumedBufferGeneration() const
    {
        return m_consumedGeneration.load( std::memory_order_acquire );
    }

    uint64_t PendingInputSerial() const
    {
        return m_pendingInputSerial.load( std::memory_order_acquire );
    }
 
private:
    std::atomic<FRAME_PACKET*> m_pending{ nullptr };
    std::atomic<uint64_t>      m_consumedGeneration{ 0 };
    std::atomic<uint64_t>      m_pendingInputSerial{ 0 };
};
 
 
} // namespace KIGFX
 
 
#endif // RHI_FRAME_MAILBOX_H