OpenMW/components/misc/guarded.hpp

#ifndef OPENMW_COMPONENTS_MISC_GUARDED_H
#define OPENMW_COMPONENTS_MISC_GUARDED_H

#include <condition_variable>
#include <memory>
#include <mutex>
#include <type_traits>

namespace Misc
{
    template <class T>
    class Locked
    {
    public:
        Locked(std::mutex& mutex, std::remove_reference_t<T>& value)
            : mLock(mutex)
            , mValue(value)
        {
        }

        std::remove_reference_t<T>& get() const { return mValue.get(); }

        std::remove_reference_t<T>* operator->() const { return &get(); }

        std::remove_reference_t<T>& operator*() const { return get(); }

    private:
        std::unique_lock<std::mutex> mLock;
        std::reference_wrapper<std::remove_reference_t<T>> mValue;
    };

    template <class T>
    class ScopeGuarded
    {
    public:
        ScopeGuarded()
            : mMutex()
            , mValue()
        {
        }

        ScopeGuarded(const T& value)
            : mMutex()
            , mValue(value)
        {
        }

        ScopeGuarded(T&& value)
            : mMutex()
            , mValue(std::move(value))
        {
        }

        template <class... Args>
        ScopeGuarded(Args&&... args)
            : mMutex()
            , mValue(std::forward<Args>(args)...)
        {
        }

        ScopeGuarded(const ScopeGuarded& other)
            : mMutex()
            , mValue(other.lock().get())
        {
        }

        ScopeGuarded(ScopeGuarded&& other)
            : mMutex()
            , mValue(std::move(other.lock().get()))
        {
        }

        Locked<T> lock() { return Locked<T>(mMutex, mValue); }

        Locked<const T> lockConst() const { return Locked<const T>(mMutex, mValue); }

        template <class Predicate>
        void wait(std::condition_variable& cv, Predicate&& predicate)
        {
            std::unique_lock<std::mutex> lock(mMutex);
            cv.wait(lock, [&] { return predicate(mValue); });
        }

    private:
        mutable std::mutex mMutex;
        T mValue;
    };
}

#endif