resourcecache.hpp

#ifndef BRAEBURN_RESOURCECACHE_HPP
#define BRAEBURN_RESOURCECACHE_HPP

#include <memory>
#include <string>
#include <unordered_map>
#include <typeindex>

namespace braeburn {

class ResourceCache {
public:
    template <typename T>
    std::shared_ptr<T> get(const std::string& name) const {
        auto& factory = cache_map.at(typeid(T));
        auto& wptr = factory.cache[name];
        auto ptr = wptr.lock();
        if (!ptr) {
            ptr = factory.create(name);
            wptr = ptr;
        }
        return std::static_pointer_cast<T>(ptr);
    }

    template <typename T>
    void enable(std::function<std::shared_ptr<void>(const std::string&)> create) {
        cache_map.emplace(typeid(T),Factory{{},std::move(create)});
    }

private:
    struct Factory {
        mutable std::unordered_map<std::string,std::weak_ptr<void>> cache;
        std::function<std::shared_ptr<void>(const std::string&)> create;
    };

    std::unordered_map<std::type_index, Factory> cache_map;
};

} // namespace braeburn

#endif // BRAEBURN_RESOURCECACHE_HPP