c25bc0c046
Change-Id: I52e22bf5e68809d6787d2d135b6a35384cf79391 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/168785 Reviewed-by: Michael Meeks <michael.meeks@collabora.com> Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com> (cherry picked from commit c7ff8768db58aaee5ce0acbabe97faeaf450f017) Reviewed-on: https://gerrit.libreoffice.org/c/core/+/172329 Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com> Tested-by: Jenkins
121 lines
3.8 KiB
C++
121 lines
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#ifndef INCLUDED_COMPHELPER_THREADPOOL_HXX
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#define INCLUDED_COMPHELPER_THREADPOOL_HXX
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#include <sal/config.h>
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#include <rtl/ref.hxx>
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#include <comphelper/comphelperdllapi.h>
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#include <mutex>
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#include <condition_variable>
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#include <cstddef>
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#include <vector>
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#include <memory>
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namespace comphelper
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{
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class ThreadTaskTag;
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class COMPHELPER_DLLPUBLIC ThreadTask
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{
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friend class ThreadPool;
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friend struct std::default_delete<ThreadTask>;
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std::shared_ptr<ThreadTaskTag> mpTag;
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/// execute this task
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void exec();
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protected:
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/// override to get your task performed by the pool
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virtual void doWork() = 0;
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/// once pushed ThreadTasks are destroyed by the pool
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virtual ~ThreadTask() {}
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public:
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ThreadTask(std::shared_ptr<ThreadTaskTag> pTag);
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};
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/// A very basic thread-safe thread pool implementation
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class COMPHELPER_DLLPUBLIC ThreadPool final
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{
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public:
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/// returns a pointer to a shared pool with optimal thread
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/// count for the CPU
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static ThreadPool& getSharedOptimalPool();
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static std::shared_ptr<ThreadTaskTag> createThreadTaskTag();
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static bool isTaskTagDone(const std::shared_ptr<ThreadTaskTag>&);
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/// returns a configurable max-concurrency
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/// limit to avoid spawning an unnecessarily
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/// large number of threads on high-core boxes.
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/// MAX_CONCURRENCY env. var. controls the cap.
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static std::size_t getPreferredConcurrency();
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ThreadPool( std::size_t nWorkers );
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~ThreadPool();
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/// push a new task onto the work queue
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void pushTask( std::unique_ptr<ThreadTask> pTask);
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/** Wait until all queued tasks associated with the tag are completed
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@param bJoin - if set call joinThreadsIfIdle() at the end
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*/
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void waitUntilDone(const std::shared_ptr<ThreadTaskTag>&, bool bJoin =
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#if defined EMSCRIPTEN
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false
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#else
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true
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#endif
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);
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/// join all threads if there are no tasks presently.
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/// return false if !isIdle()
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bool joinThreadsIfIdle();
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/// return true if there are no queued or worked-on tasks
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bool isIdle() const { return maTasks.empty() && mnBusyWorkers == 0; };
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/// return the number of live worker threads
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sal_Int32 getWorkerCount() const { return mnMaxWorkers; }
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/// wait until all work is completed, then join all threads
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void shutdown();
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private:
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ThreadPool(const ThreadPool&) = delete;
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ThreadPool& operator=(const ThreadPool&) = delete;
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class ThreadWorker;
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friend class ThreadWorker;
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/** Pop a work task
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@param bWait - if set wait until task present or termination
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@return a new task to perform, or NULL if list empty or terminated
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*/
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std::unique_ptr<ThreadTask> popWorkLocked( std::unique_lock< std::mutex > & rGuard, bool bWait );
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void shutdownLocked(std::unique_lock<std::mutex>&);
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void incBusyWorker();
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void decBusyWorker();
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/// signalled when all in-progress tasks are complete
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std::mutex maMutex;
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std::condition_variable maTasksChanged;
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bool mbTerminate;
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std::size_t const mnMaxWorkers;
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std::size_t mnBusyWorkers;
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std::vector< std::unique_ptr<ThreadTask> > maTasks;
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std::vector< rtl::Reference< ThreadWorker > > maWorkers;
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};
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} // namespace comphelper
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#endif // INCLUDED_COMPHELPER_THREADPOOL_HXX
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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