ceph/src/boost/libs/fiber/src/barrier.cpp

   1
   2 //          Copyright Oliver Kowalke 2013.
   3 // Distributed under the Boost Software License, Version 1.0.
   4 //    (See accompanying file LICENSE_1_0.txt or copy at
   5 //          http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #include "boost/fiber/barrier.hpp"
   8
   9 #include <mutex>
  10 #include <system_error>
  11
  12 #include "boost/fiber/exceptions.hpp"
  13
  14 #ifdef BOOST_HAS_ABI_HEADERS
  15 #  include BOOST_ABI_PREFIX
  16 #endif
  17
  18 namespace boost {
  19 namespace fibers {
  20
  21 barrier::barrier( std::size_t initial) :
  22         initial_{ initial },
  23         current_{ initial_ } {
  24     if ( 0 == initial) {
  25         throw fiber_error( std::make_error_code( std::errc::invalid_argument),
  26                            "boost fiber: zero initial barrier count");
  27     }
  28 }
  29
  30 bool
  31 barrier::wait() {
  32         std::unique_lock< mutex > lk( mtx_);
  33         const bool cycle = cycle_;
  34         if ( 0 == --current_) {
  35                 cycle_ = ! cycle_;
  36                 current_ = initial_;
  37         lk.unlock(); // no pessimization
  38                 cond_.notify_all();
  39                 return true;
  40         } else {
  41         cond_.wait( lk, [&](){ return cycle != cycle_; });
  42         }
  43         return false;
  44 }
  45
  46 }}
  47
  48 #ifdef BOOST_HAS_ABI_HEADERS
  49 #  include BOOST_ABI_SUFFIX
  50 #endif