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 ( BOOST_UNLIKELY( 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 std::size_t cycle = cycle_;
  34     if ( 0 == --current_) {
  35         ++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