kev/Drawer/Module/GeoSigmaDraw/Signal.h

#pragma once

#include <functional>
#include <vector>
#include <unordered_map>
#include <atomic>
#include <mutex>
#include <memory>
#include "ScopedConnection.h"

/**
 * Signal <EFBFBD>࣬<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>¼<EFBFBD>֪ͨ
 * <EFBFBD>̰߳<EFBFBD>ȫ<EFBFBD><EFBFBD>֧<EFBFBD><EFBFBD> RAII <EFBFBD><EFBFBD><EFBFBD>ӹ<EFBFBD><EFBFBD><EFBFBD>
 */
template <typename... Args>
class Signal
{
public:
    using Listener = std::function<void(Args...)>;
    using Token = size_t;

    Signal() : m_impl(std::make_shared<Impl>()) {}

    // <20><><EFBFBD><EFBFBD><EFBFBD>ƶ<EFBFBD>
    Signal(Signal&&) = default;
    Signal& operator=(Signal&&) = default;

    // <20><>ֹ<EFBFBD><D6B9><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD>ײ<EFBFBD><D7B2><EFBFBD> shared_ptr<74><72><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ᵼ<EFBFBD><E1B5BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD> Signal <20><><EFBFBD><EFBFBD>ͬһ<CDAC><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>б<EFBFBD><D0B1><EFBFBD>ͨ<EFBFBD><CDA8><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ԥ<EFBFBD>ڣ<EFBFBD>
    Signal(const Signal&) = delete;
    Signal& operator=(const Signal&) = delete;

    /**
     * @brief <EFBFBD><EFBFBD><EFBFBD>Ӽ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
     */
    Token Connect(Listener listener)
    {
        std::lock_guard lock(m_impl->mutex);
        Token token = ++m_impl->tokenCounter;
        m_impl->listeners.emplace(token, std::move(listener));
        return token;
    }

    /**
     * @brief <EFBFBD>Ƴ<EFBFBD>ָ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƶļ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
     */
    bool Disconnect(Token token)
    {
        std::lock_guard lock(m_impl->mutex);
        return m_impl->listeners.erase(token) > 0; // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƴд<C6B4>ͷ<EFBFBD><CDB7><EFBFBD>ֵ
    }

    /**
     * @brief RAII <EFBFBD>汾<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӻ<EFBFBD><EFBFBD><EFBFBD>
     */
    [[nodiscard]]
    ScopedConnection ConnectScoped(Listener listener)
    {
        Token token = Connect(std::move(listener));

        // ʹ<><CAB9> weak_ptr <20><><EFBFBD><EFBFBD>ѭ<EFBFBD><D1AD><EFBFBD><EFBFBD><EFBFBD>ã<EFBFBD><C3A3><EFBFBD><EFBFBD><EFBFBD>ֹҰָ<D2B0><D6B8><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
        std::weak_ptr<Impl> weakImpl = m_impl;

        return ScopedConnection([weakImpl, token]()
            {
                // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> weak_ptr<74><72><EFBFBD><EFBFBD><EFBFBD><EFBFBD> Signal <20>Ѿ<EFBFBD><D1BE><EFBFBD><EFBFBD><EFBFBD><EFBFBD>٣<EFBFBD>lock <20>᷵<EFBFBD>ؿ<EFBFBD>ָ<EFBFBD><D6B8>
                if (auto impl = weakImpl.lock())
                {
                    impl->Remove(token);
                }
            });
    }

    /**
     * @brief ֪ͨ<EFBFBD><EFBFBD><EFBFBD>м<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
     */
    void Emit(Args... args)
    {
        std::vector<Listener> listenersSnapshot;

        {
            std::lock_guard lock(m_impl->mutex);
            if (m_impl->listeners.empty())
            {
                return;
            }

            // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>գ<EFBFBD><D5A3><EFBFBD><EFBFBD>ص<EFBFBD><D8B5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ִ<EFBFBD><D6B4>
            // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ص<EFBFBD><D8B5>е<EFBFBD><D0B5><EFBFBD> Connect/Disconnect<63><74><EFBFBD>͵<EFBFBD><CDB5><EFBFBD><EFBFBD><EFBFBD>ʧЧ
            listenersSnapshot.reserve(m_impl->listeners.size());
            for (const auto& [token, listener] : m_impl->listeners)
            {
                listenersSnapshot.push_back(listener);
            }
        }

        for (const auto& listener : listenersSnapshot)
        {
            listener(args...);
        }
    }

    /**
     * @brief <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>м<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
     */
    void Clear()
    {
        std::lock_guard lock(m_impl->mutex);
        m_impl->listeners.clear();
    }

private:
    // <20>ڲ<EFBFBD>ʵ<EFBFBD><CAB5><EFBFBD>࣬<EFBFBD><E0A3AC> shared_ptr <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
    struct Impl
    {
        std::mutex mutex;
        std::unordered_map<Token, Listener> listeners;
        std::atomic_size_t tokenCounter{ 0 };

        void Remove(Token token)
        {
            std::lock_guard lock(mutex);
            listeners.erase(token);
        }
    };

    std::shared_ptr<Impl> m_impl;
};