delayed_controls.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2020, Raspberry Pi Ltd
 *
 * Helper to deal with controls that take effect with a delay
 */

#pragma once

#include <stdint.h>
#include <unordered_map>

#include <libcamera/controls.h>

namespace libcamera {

class V4L2Device;

class DelayedControls
{
public:
    struct ControlParams {
        unsigned int delay;
        bool priorityWrite;
    };

    DelayedControls(V4L2Device *device,
            const std::unordered_map<uint32_t, ControlParams> &controlParams);

    void reset();

    bool push(const ControlList &controls);
    ControlList get(uint32_t sequence);

    void applyControls(uint32_t sequence);

private:
    class Info : public ControlValue
    {
    public:
        Info()
            : updated(false)
        {
        }

        Info(const ControlValue &v, bool updated_ = true)
            : ControlValue(v), updated(updated_)
        {
        }

        bool updated;
    };

    /* \todo Make the listSize configurable at instance creation time. */
    static constexpr int listSize = 16;
    class ControlRingBuffer : public std::array<Info, listSize>
    {
    public:
        Info &operator[](unsigned int index)
        {
            return std::array<Info, listSize>::operator[](index % listSize);
        }

        const Info &operator[](unsigned int index) const
        {
            return std::array<Info, listSize>::operator[](index % listSize);
        }
    };

    V4L2Device *device_;
    /* \todo Evaluate if we should index on ControlId * or unsigned int */
    std::unordered_map<const ControlId *, ControlParams> controlParams_;
    unsigned int maxDelay_;

    uint32_t queueCount_;
    uint32_t writeCount_;
    /* \todo Evaluate if we should index on ControlId * or unsigned int */
    std::unordered_map<const ControlId *, ControlRingBuffer> values_;
};

} /* namespace libcamera */