Chris@102: // Copyright (C) 2014 Vicente J. Botet Escriba
Chris@102: //
Chris@102: //  Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@102: //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@102: //
Chris@102: // 2014/01 Vicente J. Botet Escriba
Chris@102: //    first implementation of a thread_executor.
Chris@102: 
Chris@102: #ifndef BOOST_THREAD_THREAD_EXECUTOR_HPP
Chris@102: #define BOOST_THREAD_THREAD_EXECUTOR_HPP
Chris@102: 
Chris@102: #include <boost/thread/detail/config.hpp>
Chris@102: #include <boost/thread/detail/delete.hpp>
Chris@102: #include <boost/thread/detail/move.hpp>
Chris@102: #include <boost/thread/executors/work.hpp>
Chris@102: #include <boost/thread/executors/executor.hpp>
Chris@102: #include <boost/thread/thread_only.hpp>
Chris@102: #include <boost/thread/scoped_thread.hpp>
Chris@102: #include <boost/thread/csbl/vector.hpp>
Chris@102: 
Chris@102: #include <boost/config/abi_prefix.hpp>
Chris@102: 
Chris@102: namespace boost
Chris@102: {
Chris@102: namespace executors
Chris@102: {
Chris@102:   class thread_executor
Chris@102:   {
Chris@102:   public:
Chris@102:     /// type-erasure to store the works to do
Chris@102:     typedef  executors::work work;
Chris@102:     bool closed_;
Chris@102:     typedef scoped_thread<> thread_t;
Chris@102:     typedef csbl::vector<thread_t> threads_type;
Chris@102:     threads_type threads_;
Chris@102:     mutable mutex mtx_;
Chris@102: 
Chris@102:     /**
Chris@102:      * Effects: try to execute one task.
Chris@102:      * Returns: whether a task has been executed.
Chris@102:      * Throws: whatever the current task constructor throws or the task() throws.
Chris@102:      */
Chris@102:     bool try_executing_one()
Chris@102:     {
Chris@102:       return false;
Chris@102:     }
Chris@102: 
Chris@102:   public:
Chris@102:     /// thread_executor is not copyable.
Chris@102:     BOOST_THREAD_NO_COPYABLE(thread_executor)
Chris@102: 
Chris@102:     /**
Chris@102:      * \b Effects: creates a inline executor that runs closures immediately.
Chris@102:      *
Chris@102:      * \b Throws: Nothing.
Chris@102:      */
Chris@102:     thread_executor()
Chris@102:     : closed_(false)
Chris@102:     {
Chris@102:     }
Chris@102:     /**
Chris@102:      * \b Effects: Waits for closures (if any) to complete, then joins and destroys the threads.
Chris@102:      *
Chris@102:      * \b Synchronization: The completion of all the closures happen before the completion of the \c thread_executor destructor.
Chris@102:      */
Chris@102:     ~thread_executor()
Chris@102:     {
Chris@102:       // signal to all the worker thread that there will be no more submissions.
Chris@102:       close();
Chris@102:       // all the scoped threads will join before destroying
Chris@102:     }
Chris@102: 
Chris@102:     /**
Chris@102:      * \b Effects: close the \c thread_executor for submissions.
Chris@102:      * The loop will work until there is no more closures to run.
Chris@102:      */
Chris@102:     void close()
Chris@102:     {
Chris@102:       lock_guard<mutex> lk(mtx_);
Chris@102:       closed_ = true;
Chris@102:     }
Chris@102: 
Chris@102:     /**
Chris@102:      * \b Returns: whether the pool is closed for submissions.
Chris@102:      */
Chris@102:     bool closed(lock_guard<mutex>& )
Chris@102:     {
Chris@102:       return closed_;
Chris@102:     }
Chris@102:     bool closed()
Chris@102:     {
Chris@102:       lock_guard<mutex> lk(mtx_);
Chris@102:       return closed(lk);
Chris@102:     }
Chris@102: 
Chris@102:     /**
Chris@102:      * \b Requires: \c Closure is a model of \c Callable(void()) and a model of \c CopyConstructible/MoveConstructible.
Chris@102:      *
Chris@102:      * \b Effects: The specified \c closure will be scheduled for execution at some point in the future.
Chris@102:      * If invoked closure throws an exception the \c thread_executor will call \c std::terminate, as is the case with threads.
Chris@102:      *
Chris@102:      * \b Synchronization: completion of \c closure on a particular thread happens before destruction of thread's thread local variables.
Chris@102:      *
Chris@102:      * \b Throws: \c sync_queue_is_closed if the thread pool is closed.
Chris@102:      * Whatever exception that can be throw while storing the closure.
Chris@102:      */
Chris@102: 
Chris@102: #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
Chris@102:     template <typename Closure>
Chris@102:     void submit(Closure & closure)
Chris@102:     {
Chris@102:       lock_guard<mutex> lk(mtx_);
Chris@102:       if (closed(lk))  BOOST_THROW_EXCEPTION( sync_queue_is_closed() );
Chris@102:       threads_.reserve(threads_.size() + 1);
Chris@102:       thread th(closure);
Chris@102:       threads_.push_back(thread_t(boost::move(th)));
Chris@102:     }
Chris@102: #endif
Chris@102:     void submit(void (*closure)())
Chris@102:     {
Chris@102:       lock_guard<mutex> lk(mtx_);
Chris@102:       if (closed(lk))  BOOST_THROW_EXCEPTION( sync_queue_is_closed() );
Chris@102:       threads_.reserve(threads_.size() + 1);
Chris@102:       thread th(closure);
Chris@102:       threads_.push_back(thread_t(boost::move(th)));
Chris@102:     }
Chris@102: 
Chris@102:     template <typename Closure>
Chris@102:     void submit(BOOST_THREAD_FWD_REF(Closure) closure)
Chris@102:     {
Chris@102:       lock_guard<mutex> lk(mtx_);
Chris@102:       if (closed(lk))  BOOST_THROW_EXCEPTION( sync_queue_is_closed() );
Chris@102:       threads_.reserve(threads_.size() + 1);
Chris@102:       thread th(boost::forward<Closure>(closure));
Chris@102:       threads_.push_back(thread_t(boost::move(th)));
Chris@102:     }
Chris@102: 
Chris@102:     /**
Chris@102:      * \b Requires: This must be called from an scheduled task.
Chris@102:      *
Chris@102:      * \b Effects: reschedule functions until pred()
Chris@102:      */
Chris@102:     template <typename Pred>
Chris@102:     bool reschedule_until(Pred const&)
Chris@102:     {
Chris@102:       return false;
Chris@102:     }
Chris@102: 
Chris@102:   };
Chris@102: }
Chris@102: using executors::thread_executor;
Chris@102: }
Chris@102: 
Chris@102: #include <boost/config/abi_suffix.hpp>
Chris@102: 
Chris@102: #endif