Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: // (C) Copyright 2013 Vicente J. Botet Escriba
Chris@16: 
Chris@16: #ifndef BOOST_THREAD_COMPLETION_LATCH_HPP
Chris@16: #define BOOST_THREAD_COMPLETION_LATCH_HPP
Chris@16: 
Chris@16: #include <boost/thread/detail/config.hpp>
Chris@16: #include <boost/thread/detail/delete.hpp>
Chris@16: #include <boost/thread/detail/counter.hpp>
Chris@16: 
Chris@16: #include <boost/thread/mutex.hpp>
Chris@16: #include <boost/thread/lock_types.hpp>
Chris@16: #include <boost/thread/condition_variable.hpp>
Chris@16: #include <boost/chrono/duration.hpp>
Chris@16: #include <boost/chrono/time_point.hpp>
Chris@16: #include <boost/assert.hpp>
Chris@101: //#include <boost/thread/detail/nullary_function.hpp>
Chris@101: #include <boost/thread/csbl/functional.hpp>
Chris@16: 
Chris@16: #include <boost/config/abi_prefix.hpp>
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16:   namespace thread_detail
Chris@16:   {
Chris@16:     void noop()
Chris@16:     {
Chris@16:     }
Chris@16:   }
Chris@16:   class completion_latch
Chris@16:   {
Chris@16:   public:
Chris@16:     /// the implementation defined completion function type
Chris@101:     //typedef detail::nullary_function<void()> completion_function;
Chris@101:     typedef csbl::function<void()> completion_function;
Chris@16:     /// noop completion function factory
Chris@16:     static completion_function noop()
Chris@16:     {
Chris@16:       return completion_function(&thread_detail::noop);
Chris@16:     }
Chris@16: 
Chris@16:   private:
Chris@16:     struct around_wait;
Chris@16:     friend struct around_wait;
Chris@16:     struct around_wait
Chris@16:     {
Chris@16:       completion_latch &that_;
Chris@16:       boost::unique_lock<boost::mutex> &lk_;
Chris@16:       around_wait(completion_latch &that, boost::unique_lock<boost::mutex> &lk)
Chris@16:       : that_(that), lk_(lk)
Chris@16:       {
Chris@16:         that_.leavers_.cond_.wait(lk, detail::counter_is_zero(that_.leavers_));
Chris@16:         that_.waiters_.inc_and_notify_all();
Chris@16:         that_.leavers_.cond_.wait(lk, detail::counter_is_not_zero(that_.leavers_));
Chris@16:       }
Chris@16:       ~around_wait()
Chris@16:       {
Chris@16:         that_.waiters_.dec_and_notify_all();
Chris@16:       }
Chris@16:     };
Chris@16: 
Chris@16:     bool count_down(unique_lock<mutex> &lk)
Chris@16:     {
Chris@16:       BOOST_ASSERT(count_ > 0);
Chris@16:       if (--count_ == 0)
Chris@16:       {
Chris@16:         waiters_.cond_.wait(lk, detail::counter_is_not_zero(waiters_));
Chris@16:         leavers_.assign_and_notify_all(waiters_);
Chris@16:         count_.cond_.notify_all();
Chris@16:         waiters_.cond_.wait(lk, detail::counter_is_zero(waiters_));
Chris@16:         leavers_.assign_and_notify_all(0);
Chris@16:         lk.unlock();
Chris@16:         funct_();
Chris@16:         return true;
Chris@16:       }
Chris@16:       return false;
Chris@16:     }
Chris@16: 
Chris@16:   public:
Chris@16:     BOOST_THREAD_NO_COPYABLE( completion_latch )
Chris@16: 
Chris@16:     /// Constructs a latch with a given count.
Chris@16:     completion_latch(std::size_t count) :
Chris@16:       count_(count), funct_(noop()), waiters_(0), leavers_(0)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     /// Constructs a latch with a given count and a completion function.
Chris@16:     template <typename F>
Chris@16:     completion_latch(std::size_t count, BOOST_THREAD_RV_REF(F) funct) :
Chris@16:     count_(count),
Chris@16:     funct_(boost::move(funct)),
Chris@16:     waiters_(0),
Chris@16:     leavers_(0)
Chris@16:     {
Chris@16:     }
Chris@16:     template <typename F>
Chris@16:     completion_latch(std::size_t count, void(*funct)()) :
Chris@16:       count_(count), funct_(funct), waiters_(0), leavers_(0)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     ///
Chris@16:     ~completion_latch()
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     /// Blocks until the latch has counted down to zero.
Chris@16:     void wait()
Chris@16:     {
Chris@16:       boost::unique_lock<boost::mutex> lk(mutex_);
Chris@16:       around_wait aw(*this, lk);
Chris@16:       count_.cond_.wait(lk, detail::counter_is_zero(count_));
Chris@16:     }
Chris@16: 
Chris@16:     /// @return true if the internal counter is already 0, false otherwise
Chris@16:     bool try_wait()
Chris@16:     {
Chris@16:       boost::unique_lock<boost::mutex> lk(mutex_);
Chris@16:       around_wait aw(*this, lk);
Chris@16:       return (count_ == 0);
Chris@16:     }
Chris@16: 
Chris@16:     /// try to wait for a specified amount of time
Chris@16:     /// @return whether there is a timeout or not.
Chris@16:     template <class Rep, class Period>
Chris@16:     cv_status wait_for(const chrono::duration<Rep, Period>& rel_time)
Chris@16:     {
Chris@16:       boost::unique_lock<boost::mutex> lk(mutex_);
Chris@16:       around_wait aw(*this, lk);
Chris@16:       return count_.cond_.wait_for(lk, rel_time, detail::counter_is_zero(count_))
Chris@16:               ? cv_status::no_timeout
Chris@16:               : cv_status::timeout;
Chris@16:     }
Chris@16: 
Chris@16:     /// try to wait until the specified time_point is reached
Chris@16:     /// @return whether there is a timeout or not.
Chris@16:     template <class Clock, class Duration>
Chris@16:     cv_status wait_until(const chrono::time_point<Clock, Duration>& abs_time)
Chris@16:     {
Chris@16:       boost::unique_lock<boost::mutex> lk(mutex_);
Chris@16:       around_wait aw(*this, lk);
Chris@16:       return count_.cond_.wait_until(lk, abs_time, detail::counter_is_zero(count_))
Chris@16:           ? cv_status::no_timeout
Chris@16:           : cv_status::timeout;
Chris@16:     }
Chris@16: 
Chris@16:     /// Decrement the count and notify anyone waiting if we reach zero.
Chris@16:     /// @Requires count must be greater than 0
Chris@16:     void count_down()
Chris@16:     {
Chris@16:       unique_lock<mutex> lk(mutex_);
Chris@16:       count_down(lk);
Chris@16:     }
Chris@16:     void signal()
Chris@16:     {
Chris@16:       count_down();
Chris@16:     }
Chris@16: 
Chris@16:     /// Decrement the count and notify anyone waiting if we reach zero.
Chris@16:     /// Blocks until the latch has counted down to zero.
Chris@16:     /// @Requires count must be greater than 0
Chris@16:     void count_down_and_wait()
Chris@16:     {
Chris@16:       boost::unique_lock<boost::mutex> lk(mutex_);
Chris@16:       if (count_down(lk))
Chris@16:       {
Chris@16:         return;
Chris@16:       }
Chris@16:       around_wait aw(*this, lk);
Chris@16:       count_.cond_.wait(lk, detail::counter_is_zero(count_));
Chris@16:     }
Chris@16:     void sync()
Chris@16:     {
Chris@16:       count_down_and_wait();
Chris@16:     }
Chris@16: 
Chris@16:     /// Reset the counter
Chris@16:     /// #Requires This method may only be invoked when there are no other threads currently inside the count_down_and_wait() method.
Chris@16:     void reset(std::size_t count)
Chris@16:     {
Chris@16:       boost::lock_guard<boost::mutex> lk(mutex_);
Chris@16:       //BOOST_ASSERT(count_ == 0);
Chris@16:       count_ = count;
Chris@16:     }
Chris@16: 
Chris@16:     /// Resets the latch with the new completion function.
Chris@16:     /// The next time the internal count reaches 0, this function will be invoked.
Chris@16:     /// This completion function may only be invoked when there are no other threads
Chris@16:     /// currently inside the count_down and wait related functions.
Chris@16:     /// It may also be invoked from within the registered completion function.
Chris@16:     /// @Returns the old completion function if any or noop if
Chris@16: 
Chris@16: #ifdef BOOST_NO_CXX11_HDR_FUNCTIONAL
Chris@16:     template <typename F>
Chris@16:     completion_function then(BOOST_THREAD_RV_REF(F) funct)
Chris@16:     {
Chris@16:       boost::lock_guard<boost::mutex> lk(mutex_);
Chris@16:       completion_function tmp(funct_);
Chris@16:       funct_ = boost::move(funct);
Chris@16:       return tmp;
Chris@16:     }
Chris@16: #endif
Chris@16:     completion_function then(void(*funct)())
Chris@16:     {
Chris@16:       boost::lock_guard<boost::mutex> lk(mutex_);
Chris@16:       completion_function tmp(funct_);
Chris@16:       funct_ = completion_function(funct);
Chris@16:       return tmp;
Chris@16:     }
Chris@16: 
Chris@16:   private:
Chris@16:     mutex mutex_;
Chris@16:     detail::counter count_;
Chris@16:     completion_function funct_;
Chris@16:     detail::counter waiters_;
Chris@16:     detail::counter leavers_;
Chris@16:   };
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/config/abi_suffix.hpp>
Chris@16: 
Chris@16: #endif