ceph/src/boost/boost/interprocess/sync/detail/common_algorithms.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2012-2013. 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 #ifndef BOOST_INTERPROCESS_SYNC_DETAIL_COMMON_ALGORITHMS_HPP
  12 #define BOOST_INTERPROCESS_SYNC_DETAIL_COMMON_ALGORITHMS_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 #include <boost/interprocess/detail/config_begin.hpp>
  23 #include <boost/interprocess/detail/workaround.hpp>
  24
  25 #include <boost/interprocess/sync/spin/wait.hpp>
  26 #include <boost/interprocess/detail/timed_utils.hpp>
  27
  28 namespace boost {
  29 namespace interprocess {
  30 namespace ipcdetail {
  31
  32 template<class MutexType, class TimePoint>
  33 bool try_based_timed_lock(MutexType &m, const TimePoint &abs_time)
  34 {
  35    //Same as lock()
  36    if(is_pos_infinity(abs_time)){
  37       m.lock();
  38       return true;
  39    }
  40    //Always try to lock to achieve POSIX guarantees:
  41    // "Under no circumstance shall the function fail with a timeout if the mutex
  42    //  can be locked immediately. The validity of the abs_timeout parameter need not
  43    //  be checked if the mutex can be locked immediately."
  44    else if(m.try_lock()){
  45       return true;
  46    }
  47    else{
  48       spin_wait swait;
  49       while(microsec_clock<TimePoint>::universal_time() < abs_time){
  50          if(m.try_lock()){
  51             return true;
  52          }
  53          swait.yield();
  54       }
  55       return false;
  56    }
  57 }
  58
  59 template<class MutexType>
  60 void try_based_lock(MutexType &m)
  61 {
  62    if(!m.try_lock()){
  63       spin_wait swait;
  64       do{
  65          if(m.try_lock()){
  66             break;
  67          }
  68          else{
  69             swait.yield();
  70          }
  71       }
  72       while(1);
  73    }
  74 }
  75
  76 template<class MutexType>
  77 void timeout_when_locking_aware_lock(MutexType &m)
  78 {
  79    #ifdef BOOST_INTERPROCESS_ENABLE_TIMEOUT_WHEN_LOCKING
  80       if (!m.timed_lock(microsec_clock<ustime>::universal_time()
  81            + usduration_milliseconds(BOOST_INTERPROCESS_TIMEOUT_WHEN_LOCKING_DURATION_MS)))
  82       {
  83          throw interprocess_exception(timeout_when_locking_error
  84                                      , "Interprocess mutex timeout when locking. Possible deadlock: "
  85                                        "owner died without unlocking?");
  86       }
  87    #else
  88       m.lock();
  89    #endif
  90 }
  91
  92 }  //namespace ipcdetail
  93 }  //namespace interprocess
  94 }  //namespace boost
  95
  96 #include <boost/interprocess/detail/config_end.hpp>
  97
  98 #endif   //BOOST_INTERPROCESS_SYNC_DETAIL_COMMON_ALGORITHMS_HPP