unplugged-system/device/google/cuttlefish/host/commands/cvd/instance_lock.h

74 lines
2.1 KiB
C++

/*
* Copyright (C) 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <set>
#include <string>
#include <fruit/fruit.h>
#include "host/commands/cvd/lock_file.h"
namespace cuttlefish {
// This class is not thread safe.
class InstanceLockFile {
friend class InstanceLockFileManager;
using LockFile = cvd_impl::LockFile;
public:
int Instance() const;
Result<InUseState> Status() const;
Result<void> Status(InUseState);
bool operator<(const InstanceLockFile&) const;
private:
InstanceLockFile(LockFile&& lock_file, const int instance_num);
LockFile lock_file_;
const int instance_num_;
};
class InstanceLockFileManager {
using LockFile = cvd_impl::LockFile;
using LockFileManager = cvd_impl::LockFileManager;
public:
INJECT(InstanceLockFileManager());
Result<InstanceLockFile> AcquireLock(int instance_num);
Result<std::set<InstanceLockFile>> AcquireLocks(const std::set<int>& nums);
Result<std::optional<InstanceLockFile>> TryAcquireLock(int instance_num);
Result<std::set<InstanceLockFile>> TryAcquireLocks(const std::set<int>& nums);
// Best-effort attempt to find a free instance id.
Result<std::optional<InstanceLockFile>> TryAcquireUnusedLock();
Result<std::vector<InstanceLockFile>> LockAllAvailable();
private:
/*
* Generate value to initialize
*/
Result<std::set<int>> FindPotentialInstanceNumsFromNetDevices();
static Result<std::string> LockFilePath(int instance_num);
std::optional<std::set<int>> all_instance_nums_;
LockFileManager lock_file_manager_;
};
} // namespace cuttlefish