Cache.h

/*
 * AUI Framework - Declarative UI toolkit for modern C++20
 * Copyright (C) 2020-2024 Alex2772 and Contributors
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
#pragma once
 
#include "AUI/Common/AString.h"
#include "AUI/Common/AMap.h"
#include "AUI/Common/SharedPtr.h"
#include "AUI/Thread/AMutex.h"
 
template<typename T, typename Container, typename K = AString>
class Cache {
private:
    AMap<K, _<T>> mContainer;
    AMutex mSync;
 
protected:
    virtual _<T> load(const K& key) = 0;
 
    virtual bool isShouldBeCached(const K& key, const _<T>& image) {
        return true;
    }
 
public:
 
    static _<T> get(const K& key) {
        Cache& i = Container::inst();
        {
            std::unique_lock lock(i.mSync);
            if (auto i = Container::inst().mContainer.contains(key)) {
                return i->second;
            }
        }
        auto value = i.load(key);
        if (i.isShouldBeCached(key, value)) {
            put(key, value);
        }
        return value;
    }
 
    static void put(const K& key, _<T> value) {
        std::unique_lock lock(Container::inst().mSync);
        Container::inst().mContainer[key] = value;
    }
 
    static void cleanup() {
        std::unique_lock lock(Container::inst().mSync);
        Container::inst().mContainer.clear();
    }
};