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- /* Thread pool
- Copyright (C) 2019-2022 Free Software Foundation, Inc.
- This file is part of GDB.
- This program 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.
- This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
- #ifndef GDBSUPPORT_THREAD_POOL_H
- #define GDBSUPPORT_THREAD_POOL_H
- #include <queue>
- #include <thread>
- #include <vector>
- #include <functional>
- #include <mutex>
- #include <condition_variable>
- #include <future>
- #include "gdbsupport/gdb_optional.h"
- namespace gdb
- {
- /* A thread pool.
- There is a single global thread pool, see g_thread_pool. Tasks can
- be submitted to the thread pool. They will be processed in worker
- threads as time allows. */
- class thread_pool
- {
- public:
- /* The sole global thread pool. */
- static thread_pool *g_thread_pool;
- ~thread_pool ();
- DISABLE_COPY_AND_ASSIGN (thread_pool);
- /* Set the thread count of this thread pool. By default, no threads
- are created -- the thread count must be set first. */
- void set_thread_count (size_t num_threads);
- /* Return the number of executing threads. */
- size_t thread_count () const
- {
- return m_thread_count;
- }
- /* Post a task to the thread pool. A future is returned, which can
- be used to wait for the result. */
- std::future<void> post_task (std::function<void ()> &&func);
- private:
- thread_pool () = default;
- /* The callback for each worker thread. */
- void thread_function ();
- /* The current thread count. */
- size_t m_thread_count = 0;
- /* A convenience typedef for the type of a task. */
- typedef std::packaged_task<void ()> task;
- /* The tasks that have not been processed yet. An optional is used
- to represent a task. If the optional is empty, then this means
- that the receiving thread should terminate. If the optional is
- non-empty, then it is an actual task to evaluate. */
- std::queue<optional<task>> m_tasks;
- /* A condition variable and mutex that are used for communication
- between the main thread and the worker threads. */
- std::condition_variable m_tasks_cv;
- std::mutex m_tasks_mutex;
- };
- }
- #endif /* GDBSUPPORT_THREAD_POOL_H */
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