77 lines
2.0 KiB
C++
77 lines
2.0 KiB
C++
/*
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* Copyright (C) 2023 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <optional>
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#include <set>
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#include <string>
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#include "common/libs/fs/shared_fd.h"
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#include "common/libs/utils/result.h"
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namespace cuttlefish {
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enum class InUseState : char {
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kInUse = 'I',
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kNotInUse = 'N',
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};
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// Replicates tempfile.gettempdir() in Python
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std::string TempDir();
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namespace cvd_impl {
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// This class is not thread safe.
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class LockFile {
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friend class LockFileManager;
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public:
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const auto& LockFilePath() const { return lock_file_path_; }
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Result<InUseState> Status() const;
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Result<void> Status(InUseState);
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// to put this into a set
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bool operator<(const LockFile& other) const;
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private:
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LockFile(SharedFD fd, const std::string& lock_file_path);
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SharedFD fd_;
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const std::string lock_file_path_;
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};
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class LockFileManager {
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public:
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LockFileManager() = default;
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Result<LockFile> AcquireLock(const std::string& lock_file_path);
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Result<std::set<LockFile>> AcquireLocks(
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const std::set<std::string>& lock_file_paths);
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Result<std::optional<LockFile>> TryAcquireLock(
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const std::string& lock_file_path);
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Result<std::set<LockFile>> TryAcquireLocks(
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const std::set<std::string>& lock_file_paths);
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// Best-effort attempt to find a free instance id.
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Result<std::optional<LockFile>> TryAcquireUnusedLock();
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static Result<SharedFD> OpenLockFile(const std::string& file_path);
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};
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} // namespace cvd_impl
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} // namespace cuttlefish
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