87 lines
2.6 KiB
C++
87 lines
2.6 KiB
C++
/*
|
|
* Copyright 2016 The Cartographer Authors
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef CARTOGRAPHER_COMMON_THREAD_POOL_H_
|
|
#define CARTOGRAPHER_COMMON_THREAD_POOL_H_
|
|
|
|
#include <deque>
|
|
#include <functional>
|
|
#include <memory>
|
|
#include <thread>
|
|
#include <vector>
|
|
|
|
#include "absl/container/flat_hash_map.h"
|
|
#include "absl/synchronization/mutex.h"
|
|
#include "cartographer/common/task.h"
|
|
|
|
namespace cartographer {
|
|
namespace common {
|
|
|
|
class Task;
|
|
|
|
class ThreadPoolInterface {
|
|
public:
|
|
ThreadPoolInterface() {}
|
|
virtual ~ThreadPoolInterface() {}
|
|
virtual std::weak_ptr<Task> Schedule(std::unique_ptr<Task> task) = 0;
|
|
|
|
protected:
|
|
void Execute(Task* task);
|
|
void SetThreadPool(Task* task);
|
|
|
|
private:
|
|
friend class Task;
|
|
|
|
virtual void NotifyDependenciesCompleted(Task* task) = 0;
|
|
};
|
|
|
|
// A fixed number of threads working on tasks. Adding a task does not block.
|
|
// Tasks may be added whether or not their dependencies are completed.
|
|
// When all dependencies of a task are completed, it is queued up for execution
|
|
// in a background thread. The queue must be empty before calling the
|
|
// destructor. The thread pool will then wait for the currently executing work
|
|
// items to finish and then destroy the threads.
|
|
class ThreadPool : public ThreadPoolInterface {
|
|
public:
|
|
explicit ThreadPool(int num_threads);
|
|
~ThreadPool();
|
|
|
|
ThreadPool(const ThreadPool&) = delete;
|
|
ThreadPool& operator=(const ThreadPool&) = delete;
|
|
|
|
// When the returned weak pointer is expired, 'task' has certainly completed,
|
|
// so dependants no longer need to add it as a dependency.
|
|
std::weak_ptr<Task> Schedule(std::unique_ptr<Task> task)
|
|
LOCKS_EXCLUDED(mutex_) override;
|
|
|
|
private:
|
|
void DoWork();
|
|
|
|
void NotifyDependenciesCompleted(Task* task) LOCKS_EXCLUDED(mutex_) override;
|
|
|
|
absl::Mutex mutex_;
|
|
bool running_ GUARDED_BY(mutex_) = true;
|
|
std::vector<std::thread> pool_ GUARDED_BY(mutex_);
|
|
std::deque<std::shared_ptr<Task>> task_queue_ GUARDED_BY(mutex_);
|
|
absl::flat_hash_map<Task*, std::shared_ptr<Task>> tasks_not_ready_
|
|
GUARDED_BY(mutex_);
|
|
};
|
|
|
|
} // namespace common
|
|
} // namespace cartographer
|
|
|
|
#endif // CARTOGRAPHER_COMMON_THREAD_POOL_H_
|