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lms/src/libs/services/artwork/impl/ImageCache.hpp
T

72 lines
2.1 KiB
C++

/*
* Copyright (C) 2015 Emeric Poupon
*
* This file is part of LMS.
*
* LMS is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* LMS is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with LMS. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <atomic>
#include <cassert>
#include <memory>
#include <optional>
#include <shared_mutex>
#include <unordered_map>
#include "database/ArtworkId.hpp"
#include "image/IEncodedImage.hpp"
namespace lms::artwork
{
class ImageCache
{
public:
ImageCache(std::size_t maxCacheSize);
struct EntryDesc
{
db::ArtworkId id;
std::optional<std::size_t> size;
bool operator==(const EntryDesc& other) const = default;
};
std::size_t getMaxCacheSize() const { return _maxCacheSize; }
void addImage(const EntryDesc& entryDesc, std::shared_ptr<image::IEncodedImage> image);
std::shared_ptr<image::IEncodedImage> getImage(const EntryDesc& entryDesc) const;
void flush();
private:
const std::size_t _maxCacheSize;
mutable std::shared_mutex _mutex;
struct EntryHasher
{
std::size_t operator()(const EntryDesc& entry) const
{
assert(entry.size); // should not cache unresized images
return std::hash<db::ArtworkId>{}(entry.id) ^ std::hash<std::size_t>{}(*entry.size);
}
};
std::unordered_map<EntryDesc, std::shared_ptr<image::IEncodedImage>, EntryHasher> _cache;
std::size_t _cacheSize{};
mutable std::atomic<std::size_t> _cacheMisses;
mutable std::atomic<std::size_t> _cacheHits;
};
} // namespace lms::artwork