Wrap an atomic value that always reflects a juce::Value for use in the audio thread

AtomicValue.h

#pragma once

#include <atomic>
#include <juce_data_structures/juce_data_structures.h>

template<typename ValueType>
class AtomicValue
{
  public:
    AtomicValue()
    {
        variantValue.addListener (&setter);
    }

    AtomicValue (juce::Value& value) : variantValue (value)
    {
        variantValue.addListener (&setter);
    }

    void attachTo (const juce::Value& value)
    {
        variantValue.referTo (value);
        atomicValue.store (ValueType (variantValue.getValue()));
    }

    ValueType get() { return atomicValue.load(); }

    void set (ValueType newValue)
    {
        variantValue.getValue() = newValue;
    }

    struct Setter : public juce::Value::Listener
    {
        Setter (std::atomic<ValueType>& atomic) : atomicValue (atomic) {}
        void valueChanged (juce::Value& value) override { atomicValue.store (ValueType (value.getValue())); }
        std::atomic<ValueType>& atomicValue;
    };

  private:
    std::atomic<ValueType> atomicValue;
    Setter                 setter { atomicValue };
    juce::Value            variantValue;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AtomicValue)
};

/* 
// Use:
AtomicValue<double> something;

juce::ValueTree tree {"Foo"};
something.attachTo (tree.getPropertyAsValue("something", nullptr));

// optional attach controls to the same value
slider.getValueObject().referTo (tree.getPropertyAsValue("something", nullptr));

// In Audio processing:
auto s = something.get(); // returns a double

*/