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Copyright 2018-2022, Barcelona Supercomputing Center (BSC), Spain
Copyright 2015-2022, Johannes Gutenberg Universitaet Mainz, Germany
This software was partially supported by the
EC H2020 funded project NEXTGenIO (Project ID: 671951, www.nextgenio.eu).
This software was partially supported by the
ADA-FS project under the SPPEXA project funded by the DFG.
This file is part of GekkoFS.
GekkoFS 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.
GekkoFS 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 GekkoFS. If not, see <https://www.gnu.org/licenses/>.
SPDX-License-Identifier: GPL-3.0-or-later
*/
/**
* @brief Class declaration for MetadataDB class which uses RocksDB and provides
* a single instance within the daemon.
*/
#ifndef GEKKOFS_METADATA_DB_HPP
#define GEKKOFS_METADATA_DB_HPP
#include <daemon/backend/exceptions.hpp>
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#include <tuple>
#include <daemon/backend/metadata/metadata_backend.hpp>
#include <daemon/backend/metadata/rocksdb_backend.hpp>
#include <daemon/backend/metadata/parallax_backend.hpp>
std::string path_;
std::shared_ptr<spdlog::logger> log_;
std::unique_ptr<AbstractMetadataBackend> backend_;
public:
MetadataDB(const std::string& path, const std::string_view database);
/**
* @brief Gets the KV store value for a key.
* @param key KV store key
* @return KV store value
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
[[nodiscard]] std::string
get(const std::string& key) const;
/**
* @brief Puts an entry into the KV store.
* @param key KV store key
* @param val KV store value
* @throws DBException
*/
void
put(const std::string& key, const std::string& val);
/**
* @brief Puts an entry into the KV store if it doesn't exist.
* @param key KV store key
* @param val KV store value
* @throws DBException on failure, ExistException if entry already exists
*/
void
put_no_exist(const std::string& key, const std::string& val);
/**
* @brief Removes an entry from the KV store.
* @param key KV store key
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
remove(const std::string& key);
/**
* @brief Checks for existence of an entry.
* @param key KV store key
* @return true if exists
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
bool
exists(const std::string& key);
/**
* Updates a metadata entry atomically and also allows to change keys.
* @param old_key KV store key to be replaced
* @param new_key new KV store key
* @param val KV store value
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
update(const std::string& old_key, const std::string& new_key,
const std::string& val);
/**
* @brief Increases only the size part of the metadata entry via a RocksDB
* Operand.
* @param key KV store key
* @param size new size for entry
* @param append
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
increase_size(const std::string& key, size_t size, bool append);
/**
* @brief Decreases only the size part of the metadata entry via a RocksDB
* Operand/
* @param key KV store key
* @param size new size for entry
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
decrease_size(const std::string& key, size_t size);
/**
* @brief Return all file names and modes for the first-level entries of the
* given directory.
* @param dir directory prefix string
* @return vector of pair <std::string name, bool is_dir>,
* where name is the name of the entries and is_dir
* is true in the case the entry is a directory.
*/
[[nodiscard]] std::vector<std::pair<std::string, bool>>
get_dirents(const std::string& dir) const;
/**
* @brief Return all file names and modes for the first-level entries of the
* given directory including their sizes and creation time.
* @param dir directory prefix string
* @return vector of pair <std::string name, bool is_dir - size - ctime>,
* where name is the name of the entries and is_dir
* is true in the case the entry is a directory.
*/
[[nodiscard]] std::vector<std::tuple<std::string, bool, size_t, time_t>>
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get_dirents_extended(const std::string& dir) const;
/**
* @brief Iterate over complete database, note ONLY used for debugging and
* is therefore unused.
*/
#endif // GEKKOFS_METADATA_DB_HPP