| /* |
| * Copyright (C) 2014, 2015 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifndef AsyncTask_h |
| #define AsyncTask_h |
| |
| #include "BAssert.h" |
| #include "Inline.h" |
| #include "Mutex.h" |
| #include "Sizes.h" |
| #include <atomic> |
| #include <condition_variable> |
| #include <thread> |
| |
| namespace bmalloc { |
| |
| template<typename Object, typename Function> |
| class AsyncTask { |
| public: |
| AsyncTask(Object&, const Function&); |
| ~AsyncTask(); |
| |
| bool willRun() { return m_state == State::Run; } |
| void run(); |
| |
| bool willRunSoon() { return m_state > State::Sleep; } |
| void runSoon(); |
| |
| private: |
| enum class State { Sleep, Run, RunSoon }; |
| |
| void runSlowCase(); |
| void runSoonSlowCase(); |
| |
| static void threadEntryPoint(AsyncTask*); |
| void threadRunLoop(); |
| |
| std::atomic<State> m_state; |
| |
| Mutex m_conditionMutex; |
| std::condition_variable_any m_condition; |
| |
| std::thread m_thread; |
| |
| Object& m_object; |
| Function m_function; |
| }; |
| |
| template<typename Object, typename Function> |
| AsyncTask<Object, Function>::AsyncTask(Object& object, const Function& function) |
| : m_state(State::Sleep) |
| , m_condition() |
| , m_thread(std::thread(&AsyncTask::threadEntryPoint, this)) |
| , m_object(object) |
| , m_function(function) |
| { |
| } |
| |
| template<typename Object, typename Function> |
| AsyncTask<Object, Function>::~AsyncTask() |
| { |
| // We'd like to mark our destructor deleted but C++ won't allow it because |
| // we are an automatic member of Heap. |
| RELEASE_BASSERT(0); |
| } |
| |
| template<typename Object, typename Function> |
| void AsyncTask<Object, Function>::run() |
| { |
| m_state = State::Run; |
| |
| std::lock_guard<Mutex> lock(m_conditionMutex); |
| m_condition.notify_all(); |
| } |
| |
| template<typename Object, typename Function> |
| void AsyncTask<Object, Function>::runSoon() |
| { |
| m_state = State::RunSoon; |
| |
| std::lock_guard<Mutex> lock(m_conditionMutex); |
| m_condition.notify_all(); |
| } |
| |
| template<typename Object, typename Function> |
| void AsyncTask<Object, Function>::threadEntryPoint(AsyncTask* asyncTask) |
| { |
| #if BOS(DARWIN) |
| pthread_set_qos_class_self_np(QOS_CLASS_USER_INTERACTIVE, 0); |
| #endif |
| |
| asyncTask->threadRunLoop(); |
| } |
| |
| template<typename Object, typename Function> |
| void AsyncTask<Object, Function>::threadRunLoop() |
| { |
| // This loop ratchets downward from most active to least active state. While |
| // we ratchet downward, any other thread may reset our state. |
| |
| // We require any state change while we are sleeping to signal to our |
| // condition variable and wake us up. |
| |
| while (1) { |
| if (m_state == State::Sleep) { |
| std::unique_lock<Mutex> lock(m_conditionMutex); |
| m_condition.wait(lock, [&]() { return m_state != State::Sleep; }); |
| } |
| |
| if (m_state == State::RunSoon) { |
| std::unique_lock<Mutex> lock(m_conditionMutex); |
| m_condition.wait_for(lock, asyncTaskSleepDuration, [&]() { return m_state != State::RunSoon; }); |
| } |
| |
| m_state = State::Sleep; |
| (m_object.*m_function)(); |
| } |
| } |
| |
| } // namespace bmalloc |
| |
| #endif // AsyncTask_h |