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// Copyright Contributors to the DNF5 project.
// Copyright Contributors to the libdnf project.
// SPDX-License-Identifier: LGPL-2.1-or-later
//
// This file is part of libdnf: https://github.com/rpm-software-management/libdnf/
//
// Libdnf is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 2.1 of the License, or
// (at your option) any later version.
//
// Libdnf 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with libdnf. If not, see <https://www.gnu.org/licenses/>.
#ifndef LIBDNF5_UTILS_LOCKER_HPP
#define LIBDNF5_UTILS_LOCKER_HPP
#include "libdnf5/common/impl_ptr.hpp"
#include "libdnf5/defs.h"
#include <filesystem>
namespace libdnf5::utils {
enum class LIBDNF_API LockAccess { READ, WRITE };
enum class LIBDNF_API LockBlocking { NON_BLOCKING, BLOCKING };
/// Object for implementing a simple file mutex mechanism
/// or checking read/write access on a given path.
class LIBDNF_API Locker {
public:
/// Create a Locker object at a given path
Locker(const std::filesystem::path & path, bool keep_file = false);
~Locker();
Locker(const Locker &) = delete;
Locker & operator=(const Locker &) = delete;
Locker(Locker &&) noexcept;
Locker & operator=(Locker &&) noexcept;
/// @brief Acquire a read or write lock on a given file path, either blocking or non-blocking.
/// @return True if lock acquisition was successful, otherwise false
/// @throws libdnf5::SystemError if an unexpected error occurs when checking the lock state, like insufficient privileges
bool lock(LockAccess type, LockBlocking blocking);
/// @brief Try to acquire read lock on a given file path
/// @return True if lock acquisition was successful, otherwise false
/// @throws libdnf5::SystemError if an unexpected error occurs when checking the lock state, like insufficient privileges
bool read_lock();
/// @brief Try to acquire write lock on a given file path
/// @return True if lock acquisition was successful, otherwise false
/// @throws libdnf5::SystemError if an unexpected error occurs when checking the lock state, like insufficient privileges
bool write_lock();
/// @brief Unlock the existing lock and remove the underlying lock file
/// @throws libdnf5::SystemError if an unexpected error occurs when unlocking
void unlock();
/// @brief Open the file but don't acquire a lock yet. Useful for checking permissions.
/// @throws libdnf5::SystemError if an unexpected error occurs when opening the file
void open_file(LockAccess type);
/// @brief Get the path being locked
const std::filesystem::path & get_path() const noexcept;
private:
class LIBDNF_LOCAL Impl;
ImplPtr<Impl> p_impl;
};
} // namespace libdnf5::utils
#endif // LIBDNF5_UTILS_LOCKER_HPP
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