boost之第三方线程池

简介

其是模板类，支持future，下载地址为threadpool，基实现是基于pimpl即pool_core_type

结构

SchedulingPolicy调度策略有：fifo_scheduler,lifo_scheduler,prio_scheduler
SchedulingPolicy关闭策略有：wait_for_all_tasks,wait_for_active_tasks,immediately
SizePolicyController线程池大小控制器策略有：empty_controller,resize_controller
SizePolicy大小策略有： static_size
task适配器类型有：prio_task_func,looped_task_func和支持future的future_impl_task_func

支持future

schedule：首先创建future_impl，然后根据future_impl创建future和future_impl_task_func，同时返回future

template<class Pool, class Function>
typename disable_if < is_void< typename result_of< Function() >::type >,future< typename result_of< Function() >::type >
>::type
schedule(Pool& pool, const Function& task)
{typedef typename result_of< Function() >::type future_result_type;// create future impl and futureshared_ptr<detail::future_impl<future_result_type> > impl(new detail::future_impl<future_result_type>);future <future_result_type> res(impl);// schedule future implpool.schedule(detail::future_impl_task_func<detail::future_impl, Function>(task, impl));// return futurereturn res;
}

线程池适配器

有两类函数模板，其中的一个是对象要求有run方法，另外一个就是要求是pool中的task类型

 template<typename Pool, typename Runnable>bool schedule(Pool& pool, shared_ptr<Runnable> const & obj){	return pool->schedule(bind(&Runnable::run, obj));}	template<typename Pool>typename enable_if < is_void< typename result_of< typename Pool::task_type() >::type >,bool>::typeschedule(Pool& pool, typename Pool::task_type const & task){	return pool.schedule(task);}	template<typename Pool>typename enable_if < is_void< typename result_of< typename Pool::task_type() >::type >,bool>::typeschedule(shared_ptr<Pool> const pool, typename Pool::task_type const & task){	return pool->schedule(task);}	

工作线程worker_thread

create_and_attach：静态方法，用于创建worker_thread

static void create_and_attach(shared_ptr<pool_type> const & pool){shared_ptr<worker_thread> worker(new worker_thread(pool));if(worker){worker->m_thread.reset(new boost::thread(bind(&worker_thread::run, worker)));}}

run：工作线程的执行体

void run()
{ scope_guard notify_exception(bind(&worker_thread::died_unexpectedly, this));while(m_pool->execute_task()) {}notify_exception.disable();m_pool->worker_destructed(this->shared_from_this());
}

当在执行execute_task异常退出时会执行notify_exception即died_unexpectedly

scope_guard

用于在工作线程异常退出时执行退出对应的操作

在析构时，执行m_function

~scope_guard()
{if(m_is_active && m_function){m_function();}
}

locking_ptr

对指针对象的安全操作，主要用于future_impl的线程安全操作

构造函数中上锁，析构函数中解锁

locking_ptr(volatile T& obj, const volatile Mutex& mtx): m_obj(const_cast<T*>(&obj)), m_mutex(*const_cast<Mutex*>(&mtx)){   // Lock mutexm_mutex.lock();}/// Destructor.~locking_ptr(){ // Unlock mutexm_mutex.unlock();}

operator*获取指针所指的对象，operator->获取对象指针

T& operator*() const{    return *m_obj;    }/*! Returns a pointer to the stored instance.* \return The instance's pointer.*/T* operator->() const{   return m_obj;   }