value_source_binding.hpp

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#pragma once

 
#include <memory>
 
#include <pulp/view/value_source.hpp>
 
namespace pulp::view {
 
class View;
class FrameClock;

class FrameClockBinding {
public:
    using Tick = bool (*)(void* context, float dt);
 
    FrameClockBinding(View& owner, Tick tick, void* context);
    ~FrameClockBinding();
 
    FrameClockBinding(const FrameClockBinding&) = delete;
    FrameClockBinding& operator=(const FrameClockBinding&) = delete;

    void set_wanted(bool wanted) { wanted_ = wanted; }
    bool wanted() const { return wanted_; }

    void refresh();

    void stop();
 
    bool subscribed() const { return sub_id_ != -1; }
    FrameClock* subscribed_clock() const { return subscribed_clock_; }
    View& owner() const { return owner_; }
 
private:
    friend class View;

    bool on_frame(float dt);
 
    View& owner_;
    Tick tick_;
    void* context_;
    FrameClockBinding* next_ = nullptr;      // owner's intrusive enrolment list
    bool wanted_ = false;                    // owner has something to read
    int sub_id_ = -1;                        // FrameClock subscription id, -1 = none
    FrameClock* subscribed_clock_ = nullptr; // cached for unsubscribe
};

class MeterSourceBinding {
public:
    explicit MeterSourceBinding(View& owner)
        : binding_(owner, &MeterSourceBinding::tick, this) {}

    void set_source(std::shared_ptr<MeterSource> source, int channel);

    void set_active(bool active);
    bool active() const { return active_; }

    void refresh() { binding_.refresh(); }
    void stop() { binding_.stop(); }

    const MeterFrame& frame() const { return frame_; }
 
    bool has_source() const { return static_cast<bool>(source_); }
    int channel() const { return channel_; }
    bool subscribed() const { return binding_.subscribed(); }
    FrameClock* subscribed_clock() const { return binding_.subscribed_clock(); }
 
private:
    static bool tick(void* context, float dt);
    void update_wanted() { binding_.set_wanted(source_ && active_); }
 
    FrameClockBinding binding_;
    std::shared_ptr<MeterSource> source_;
    int channel_ = 0;
    bool active_ = true;
    MeterFrame frame_{};
};

class ScalarSourceBinding {
public:
    explicit ScalarSourceBinding(View& owner)
        : binding_(owner, &ScalarSourceBinding::tick, this) {}

    void set_source(std::shared_ptr<ScalarSource> source);

    void set_active(bool active);
    bool active() const { return active_; }
 
    void refresh() { binding_.refresh(); }
    void stop() { binding_.stop(); }

    float value() const { return value_; }
 
    bool has_source() const { return static_cast<bool>(source_); }
    bool subscribed() const { return binding_.subscribed(); }
    FrameClock* subscribed_clock() const { return binding_.subscribed_clock(); }
 
private:
    static bool tick(void* context, float dt);
    void update_wanted() { binding_.set_wanted(source_ && active_); }
 
    FrameClockBinding binding_;
    std::shared_ptr<ScalarSource> source_;
    bool active_ = true;
    float value_ = 0.0f;
};
 
} // namespace pulp::view