qswiki/cache/mapcache.h

#ifndef MAPCACHE_H
#define MAPCACHE_H
#include <map>
#include <set>
#include <shared_mutex>
#include <optional>
#include <string>
#include "icache.h"

/* Thread-Safe Key-Value store */
template <class T> class MapCache
{
  private:
	std::unordered_map<std::string, T> cache;
	mutable std::shared_mutex sharedMutex;

  public:
	std::optional<T> find(const std::string &key) const
	{
		std::shared_lock<std::shared_mutex> lock(this->sharedMutex);
		auto it = this->cache.find(key);
		if(it != this->cache.end())
		{
			return it->second;
		}
		return {};
	}
	void set(const std::string &key, const T &val)
	{
		std::lock_guard<std::shared_mutex> lock{sharedMutex};
		this->cache[key] = val;
	}
	void clear()
	{
		std::lock_guard<std::shared_mutex> lock{sharedMutex};
		this->cache.clear();
	}

	void remove(const std::string &key)
	{
		std::lock_guard<std::shared_mutex> lock{sharedMutex};
		this->cache.erase(key);
	}

	void removePrefix(const std::string &key)
	{
		std::lock_guard<std::shared_mutex> lock{sharedMutex};
		std::erase_if(this->cache, [key](const auto &item)
		{
			auto const& [k, v] = item;
			return k.starts_with(std::string_view(key));
		});
	}

};


class StringCache : public MapCache<std::string>, public ICache
{
	virtual std::optional<std::string> get(std::string_view key) const override
	{
		return MapCache<std::string>::find(std::string(key));
	}

	virtual void put(std::string_view key, std::string val) override
	{
		MapCache<std::string>::set(std::string(key), val);
	}

	virtual void remove(std::string_view key) override
	{
		MapCache<std::string>::remove(std::string(key));
	}

	virtual void removePrefix(std::string_view prefix)
	{
		MapCache<std::string>::removePrefix(std::string(prefix));
	}

	virtual void clear() override
	{
		MapCache<std::string>::clear();
	}

};

#endif // MAPCACHE_H