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62 lines
1.6 KiB
C++
62 lines
1.6 KiB
C++
#pragma once
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#include <cstdint>
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#include <thread>
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#include <mutex>
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#include <condition_variable>
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#include <functional>
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#include <queue>
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#include <vector>
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/** Very simple thread pool similar to boost::threadpool.
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* Advantages:
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* - catches exceptions and rethrows on wait.
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*/
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class ThreadPool
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{
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private:
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using Job = std::function<void()>;
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public:
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/// Size is constant, all threads are created immediately.
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ThreadPool(size_t m_size);
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/// Add new job. Locks until free thread in pool become available or exception in one of threads was thrown.
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/// If an exception in some thread was thrown, method silently returns, and exception will be rethrown only on call to 'wait' function.
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void schedule(Job job);
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/// Wait for all currently active jobs to be done.
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/// You may call schedule and wait many times in arbitary order.
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/// If any thread was throw an exception, first exception will be rethrown from this method,
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/// and exception will be cleared.
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void wait();
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/// Waits for all threads. Doesn't rethrow exceptions (use 'wait' method to rethrow exceptions).
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/// You should not destroy object while calling schedule or wait methods from another threads.
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~ThreadPool();
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size_t size() const { return m_size; }
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/// Returns number of active jobs.
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size_t active() const;
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private:
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mutable std::mutex mutex;
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std::condition_variable has_free_thread;
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std::condition_variable has_new_job_or_shutdown;
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const size_t m_size;
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size_t active_jobs = 0;
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bool shutdown = false;
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std::queue<Job> jobs;
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std::vector<std::thread> threads;
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std::exception_ptr first_exception;
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void worker();
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};
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