117 lines
3.0 KiB
C++
117 lines
3.0 KiB
C++
/************************************************************************************
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*
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* D++, A Lightweight C++ library for Discord
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*
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* SPDX-License-Identifier: Apache-2.0
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* Copyright 2021 Craig Edwards and D++ contributors
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* (https://github.com/brainboxdotcc/DPP/graphs/contributors)
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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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************************************************************************************/
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#pragma once
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#include <thread>
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#include <queue>
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#include <vector>
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#include <condition_variable>
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#include <mutex>
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#include <functional>
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namespace dpp {
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/**
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* @brief A work unit is a lambda executed in the thread pool
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*/
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using work_unit = std::function<void()>;
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/**
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* @brief A task within a thread pool. A simple lambda that accepts no parameters and returns void.
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*/
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struct DPP_EXPORT thread_pool_task {
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/**
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* @brief Task priority, lower value is higher priority
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*/
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int priority;
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/**
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* @brief Work unit to execute as the task
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*/
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work_unit function;
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};
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/**
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* @brief Compares two thread pool tasks by priority
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*/
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struct DPP_EXPORT thread_pool_task_comparator {
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/**
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* @brief Compare two tasks
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* @param a first task
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* @param b second task
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* @return true if a > b
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*/
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bool operator()(const thread_pool_task &a, const thread_pool_task &b) const {
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return a.priority > b.priority;
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};
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};
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/**
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* @brief A thread pool contains 1 or more worker threads which accept thread_pool_task lambadas
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* into a queue, which is processed in-order by whichever thread is free.
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*/
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struct DPP_EXPORT thread_pool {
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/**
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* @brief Threads that comprise the thread pool
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*/
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std::vector<std::thread> threads;
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/**
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* @brief Priority queue of tasks to be executed
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*/
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std::priority_queue<thread_pool_task, std::vector<thread_pool_task>, thread_pool_task_comparator> tasks;
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/**
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* @brief Mutex for accessing the priority queue
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*/
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std::mutex queue_mutex;
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/**
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* @brief Condition variable to notify for new tasks to run
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*/
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std::condition_variable cv;
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/**
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* @brief True if the thread pool is due to stop
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*/
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bool stop{false};
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/**
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* @brief Create a new priority thread pool
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* @param creator creating cluster (for logging)
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* @param num_threads number of threads in the pool
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*/
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explicit thread_pool(class cluster* creator, size_t num_threads = std::thread::hardware_concurrency());
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/**
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* @brief Destroy the thread pool
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*/
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~thread_pool();
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/**
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* @brief Enqueue a new task to the thread pool
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* @param task task to enqueue
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*/
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void enqueue(thread_pool_task task);
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};
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} |