ceph/src/boost/boost/interprocess/sync/spin/interprocess_barrier.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2006. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/interprocess for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10
  11 #include<boost/interprocess/exceptions.hpp>
  12 #include <boost/interprocess/sync/scoped_lock.hpp>
  13
  14 #ifndef BOOST_CONFIG_HPP
  15 #  include <boost/config.hpp>
  16 #endif
  17 #
  18 #if defined(BOOST_HAS_PRAGMA_ONCE)
  19 #  pragma once
  20 #endif
  21
  22 namespace boost {
  23 namespace interprocess {
  24
  25 inline barrier::barrier(unsigned int count)
  26    : m_threshold(count), m_count(count), m_generation(0)
  27 {
  28    if (count == 0)
  29       throw std::invalid_argument("count cannot be zero.");
  30 }
  31
  32 inline barrier::~barrier(){}
  33
  34 inline bool barrier::wait()
  35 {
  36    scoped_lock<interprocess_mutex> lock(m_mutex);
  37    unsigned int gen = m_generation;
  38
  39    if (--m_count == 0){
  40       m_generation++;
  41       m_count = m_threshold;
  42       m_cond.notify_all();
  43       return true;
  44    }
  45
  46    while (gen == m_generation){
  47       m_cond.wait(lock);
  48    }
  49    return false;
  50 }
  51
  52 }  //namespace interprocess {
  53 }  //namespace boost {