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/***
This file is part of snapcast
Copyright (C) 2014-2024 Johannes Pohl
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
***/
#pragma once
// 3rd party headers
#include <boost/algorithm/hex.hpp>
#include <boost/uuid/detail/md5.hpp>
// standard headers
#include <map>
#include <mutex>
#include <optional>
#include <string>
/// Image cache, used to store current album art per stream
class ImageCache
{
public:
/// @return singleton to the image cache
static ImageCache& instance()
{
static ImageCache instance_;
return instance_;
}
/// Store the base64 encoded @p image for @p key (the session that stores the image) in the cache
/// @return url of the cached image (md5 of key + image data) appended with @p extension
std::string setImage(const std::string& key, std::string image, const std::string& extension)
{
if (image.empty())
{
clear(key);
return "";
}
using boost::uuids::detail::md5;
md5 hash;
md5::digest_type digest;
hash.process_bytes(key.data(), key.size());
hash.process_bytes(image.data(), image.size());
hash.get_digest(digest);
std::string filename;
const auto* intDigest = reinterpret_cast<const int*>(&digest);
boost::algorithm::hex_lower(intDigest, intDigest + (sizeof(md5::digest_type) / sizeof(int)), std::back_inserter(filename));
auto ext = extension;
if (ext.find('.') == 0)
ext = ext.substr(1);
filename += "." + ext;
std::lock_guard<std::mutex> lock(mutex_);
key_to_url_[key] = filename;
url_to_data_[filename] = std::move(image);
return filename;
};
/// Clear image for @p key (the stream session's name)
void clear(const std::string& key)
{
std::lock_guard<std::mutex> lock(mutex_);
auto iter = key_to_url_.find(key);
if (iter != key_to_url_.end())
{
auto url = *iter;
auto url_iter = url_to_data_.find(url.second);
if (url_iter != url_to_data_.end())
url_to_data_.erase(url_iter);
key_to_url_.erase(iter);
}
}
/// @return base64 encoded image for url (the one returned by "setImage")
std::optional<std::string> getImage(const std::string& url)
{
std::lock_guard<std::mutex> lock(mutex_);
auto iter = url_to_data_.find(url);
if (iter == url_to_data_.end())
return std::nullopt;
else
return iter->second;
}
private:
ImageCache() = default;
~ImageCache() = default;
std::map<std::string, std::string> key_to_url_;
std::map<std::string, std::string> url_to_data_;
std::mutex mutex_;
};
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