717 lines
22 KiB
Plaintext
717 lines
22 KiB
Plaintext
#ifndef BOOST_THREAD_PTHREAD_SHARED_MUTEX_HPP
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#define BOOST_THREAD_PTHREAD_SHARED_MUTEX_HPP
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// (C) Copyright 2006-8 Anthony Williams
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// (C) Copyright 2012 Vicente J. Botet Escriba
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <boost/assert.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/thread/mutex.hpp>
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#include <boost/thread/condition_variable.hpp>
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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#include <boost/thread/detail/thread_interruption.hpp>
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#endif
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#ifdef BOOST_THREAD_USES_CHRONO
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#include <boost/chrono/system_clocks.hpp>
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#include <boost/chrono/ceil.hpp>
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#endif
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#include <boost/thread/detail/delete.hpp>
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#include <boost/assert.hpp>
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#include <boost/config/abi_prefix.hpp>
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namespace boost
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{
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class shared_mutex
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{
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private:
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class state_data
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{
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public:
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state_data () :
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shared_count(0),
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exclusive(false),
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upgrade(false),
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exclusive_waiting_blocked(false)
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{}
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void assert_free() const
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{
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BOOST_ASSERT( ! exclusive );
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BOOST_ASSERT( ! upgrade );
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BOOST_ASSERT( shared_count==0 );
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}
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void assert_locked() const
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{
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BOOST_ASSERT( exclusive );
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BOOST_ASSERT( shared_count==0 );
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BOOST_ASSERT( ! upgrade );
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}
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void assert_lock_shared () const
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{
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BOOST_ASSERT( ! exclusive );
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BOOST_ASSERT( shared_count>0 );
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//BOOST_ASSERT( (! upgrade) || (shared_count>1));
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// if upgraded there are at least 2 threads sharing the mutex,
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// except when unlock_upgrade_and_lock has decreased the number of readers but has not taken yet exclusive ownership.
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}
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void assert_lock_upgraded () const
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{
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BOOST_ASSERT( ! exclusive );
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BOOST_ASSERT( upgrade );
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BOOST_ASSERT( shared_count>0 );
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}
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void assert_lock_not_upgraded () const
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{
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BOOST_ASSERT( ! upgrade );
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}
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bool can_lock () const
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{
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return ! (shared_count || exclusive);
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}
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void exclusive_blocked (bool blocked)
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{
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exclusive_waiting_blocked = blocked;
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}
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void lock ()
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{
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exclusive = true;
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}
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void unlock ()
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{
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exclusive = false;
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exclusive_waiting_blocked = false;
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}
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bool can_lock_shared () const
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{
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return ! (exclusive || exclusive_waiting_blocked);
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}
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bool more_shared () const
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{
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return shared_count > 0 ;
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}
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unsigned get_shared_count () const
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{
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return shared_count ;
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}
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unsigned lock_shared ()
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{
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return ++shared_count;
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}
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void unlock_shared ()
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{
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--shared_count;
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}
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bool unlock_shared_downgrades()
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{
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if (upgrade) {
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upgrade=false;
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exclusive=true;
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return true;
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} else {
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exclusive_waiting_blocked=false;
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return false;
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}
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}
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void lock_upgrade ()
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{
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++shared_count;
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upgrade=true;
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}
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bool can_lock_upgrade () const
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{
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return ! (exclusive || exclusive_waiting_blocked || upgrade);
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}
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void unlock_upgrade ()
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{
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upgrade=false;
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--shared_count;
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}
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//private:
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unsigned shared_count;
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bool exclusive;
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bool upgrade;
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bool exclusive_waiting_blocked;
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};
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state_data state;
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boost::mutex state_change;
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boost::condition_variable shared_cond;
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boost::condition_variable exclusive_cond;
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boost::condition_variable upgrade_cond;
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void release_waiters()
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{
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exclusive_cond.notify_one();
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shared_cond.notify_all();
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}
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public:
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BOOST_THREAD_NO_COPYABLE(shared_mutex)
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shared_mutex()
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{
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}
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~shared_mutex()
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{
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}
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void lock_shared()
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(!state.can_lock_shared())
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{
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shared_cond.wait(lk);
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}
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state.lock_shared();
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}
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bool try_lock_shared()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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if(!state.can_lock_shared())
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{
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return false;
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}
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state.lock_shared();
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return true;
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}
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#if defined BOOST_THREAD_USES_DATETIME
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bool timed_lock_shared(system_time const& timeout)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(!state.can_lock_shared())
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{
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if(!shared_cond.timed_wait(lk,timeout))
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{
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return false;
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}
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}
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state.lock_shared();
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return true;
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}
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template<typename TimeDuration>
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bool timed_lock_shared(TimeDuration const & relative_time)
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{
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return timed_lock_shared(get_system_time()+relative_time);
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}
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#endif
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#ifdef BOOST_THREAD_USES_CHRONO
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template <class Rep, class Period>
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bool try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time)
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{
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return try_lock_shared_until(chrono::steady_clock::now() + rel_time);
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}
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template <class Clock, class Duration>
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bool try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(!state.can_lock_shared())
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//while(state.exclusive || state.exclusive_waiting_blocked)
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{
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if(cv_status::timeout==shared_cond.wait_until(lk,abs_time))
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{
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return false;
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}
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}
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state.lock_shared();
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return true;
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}
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#endif
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void unlock_shared()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_lock_shared();
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state.unlock_shared();
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if (! state.more_shared())
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{
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if (state.upgrade)
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{
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// As there is a thread doing a unlock_upgrade_and_lock that is waiting for ! state.more_shared()
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// avoid other threads to lock, lock_upgrade or lock_shared, so only this thread is notified.
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state.upgrade=false;
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state.exclusive=true;
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//lk.unlock();
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upgrade_cond.notify_one();
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}
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else
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{
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state.exclusive_waiting_blocked=false;
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//lk.unlock();
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}
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release_waiters();
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}
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}
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void lock()
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while (state.shared_count || state.exclusive)
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{
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state.exclusive_waiting_blocked=true;
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exclusive_cond.wait(lk);
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}
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state.exclusive=true;
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}
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#if defined BOOST_THREAD_USES_DATETIME
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bool timed_lock(system_time const& timeout)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(state.shared_count || state.exclusive)
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{
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state.exclusive_waiting_blocked=true;
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if(!exclusive_cond.timed_wait(lk,timeout))
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{
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if(state.shared_count || state.exclusive)
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{
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state.exclusive_waiting_blocked=false;
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release_waiters();
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return false;
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}
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break;
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}
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}
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state.exclusive=true;
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return true;
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}
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template<typename TimeDuration>
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bool timed_lock(TimeDuration const & relative_time)
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{
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return timed_lock(get_system_time()+relative_time);
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}
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#endif
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#ifdef BOOST_THREAD_USES_CHRONO
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template <class Rep, class Period>
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time)
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{
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return try_lock_until(chrono::steady_clock::now() + rel_time);
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}
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template <class Clock, class Duration>
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(state.shared_count || state.exclusive)
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{
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state.exclusive_waiting_blocked=true;
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if(cv_status::timeout == exclusive_cond.wait_until(lk,abs_time))
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{
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if(state.shared_count || state.exclusive)
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{
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state.exclusive_waiting_blocked=false;
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release_waiters();
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return false;
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}
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break;
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}
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}
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state.exclusive=true;
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return true;
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}
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#endif
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bool try_lock()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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if(state.shared_count || state.exclusive)
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{
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return false;
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}
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else
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{
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state.exclusive=true;
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return true;
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}
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}
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void unlock()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_locked();
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state.exclusive=false;
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state.exclusive_waiting_blocked=false;
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state.assert_free();
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release_waiters();
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}
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void lock_upgrade()
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(state.exclusive || state.exclusive_waiting_blocked || state.upgrade)
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{
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shared_cond.wait(lk);
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}
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state.lock_shared();
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state.upgrade=true;
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}
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#if defined BOOST_THREAD_USES_DATETIME
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bool timed_lock_upgrade(system_time const& timeout)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(state.exclusive || state.exclusive_waiting_blocked || state.upgrade)
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{
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if(!shared_cond.timed_wait(lk,timeout))
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{
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if(state.exclusive || state.exclusive_waiting_blocked || state.upgrade)
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{
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return false;
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}
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break;
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}
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}
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state.lock_shared();
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state.upgrade=true;
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return true;
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}
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template<typename TimeDuration>
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bool timed_lock_upgrade(TimeDuration const & relative_time)
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{
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return timed_lock_upgrade(get_system_time()+relative_time);
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}
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#endif
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#ifdef BOOST_THREAD_USES_CHRONO
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template <class Rep, class Period>
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bool try_lock_upgrade_for(const chrono::duration<Rep, Period>& rel_time)
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{
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return try_lock_upgrade_until(chrono::steady_clock::now() + rel_time);
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}
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template <class Clock, class Duration>
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bool try_lock_upgrade_until(const chrono::time_point<Clock, Duration>& abs_time)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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while(state.exclusive || state.exclusive_waiting_blocked || state.upgrade)
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{
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if(cv_status::timeout == shared_cond.wait_until(lk,abs_time))
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{
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if(state.exclusive || state.exclusive_waiting_blocked || state.upgrade)
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{
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return false;
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}
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break;
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}
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}
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state.lock_shared();
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state.upgrade=true;
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return true;
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}
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#endif
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bool try_lock_upgrade()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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if(state.exclusive || state.exclusive_waiting_blocked || state.upgrade)
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{
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return false;
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}
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else
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{
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state.lock_shared();
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state.upgrade=true;
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state.assert_lock_upgraded();
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return true;
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}
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}
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void unlock_upgrade()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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//state.upgrade=false;
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state.unlock_upgrade();
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if(! state.more_shared() )
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{
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state.exclusive_waiting_blocked=false;
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release_waiters();
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} else {
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shared_cond.notify_all();
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}
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}
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// Upgrade <-> Exclusive
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void unlock_upgrade_and_lock()
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_lock_upgraded();
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state.unlock_shared();
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while (state.more_shared())
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{
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upgrade_cond.wait(lk);
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}
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state.upgrade=false;
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state.exclusive=true;
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state.assert_locked();
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}
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void unlock_and_lock_upgrade()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_locked();
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state.exclusive=false;
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state.upgrade=true;
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state.lock_shared();
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state.exclusive_waiting_blocked=false;
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state.assert_lock_upgraded();
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release_waiters();
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}
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bool try_unlock_upgrade_and_lock()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_lock_upgraded();
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if( !state.exclusive
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&& !state.exclusive_waiting_blocked
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&& state.upgrade
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&& state.shared_count==1)
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{
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state.shared_count=0;
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state.exclusive=true;
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state.upgrade=false;
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state.assert_locked();
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return true;
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}
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return false;
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}
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#ifdef BOOST_THREAD_USES_CHRONO
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template <class Rep, class Period>
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bool
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try_unlock_upgrade_and_lock_for(
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const chrono::duration<Rep, Period>& rel_time)
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{
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return try_unlock_upgrade_and_lock_until(
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chrono::steady_clock::now() + rel_time);
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}
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template <class Clock, class Duration>
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bool
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try_unlock_upgrade_and_lock_until(
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const chrono::time_point<Clock, Duration>& abs_time)
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{
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#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
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boost::this_thread::disable_interruption do_not_disturb;
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#endif
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_lock_upgraded();
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if (state.shared_count != 1)
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{
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for (;;)
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{
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cv_status status = shared_cond.wait_until(lk,abs_time);
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if (state.shared_count == 1)
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break;
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if(status == cv_status::timeout)
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return false;
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}
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}
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state.upgrade=false;
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state.exclusive=true;
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state.exclusive_waiting_blocked=false;
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state.shared_count=0;
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return true;
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}
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#endif
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// Shared <-> Exclusive
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void unlock_and_lock_shared()
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{
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boost::unique_lock<boost::mutex> lk(state_change);
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state.assert_locked();
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state.exclusive=false;
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state.lock_shared();
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state.exclusive_waiting_blocked=false;
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release_waiters();
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}
|
|
|
|
#ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS
|
|
bool try_unlock_shared_and_lock()
|
|
{
|
|
boost::unique_lock<boost::mutex> lk(state_change);
|
|
state.assert_lock_shared();
|
|
if( !state.exclusive
|
|
&& !state.exclusive_waiting_blocked
|
|
&& !state.upgrade
|
|
&& state.shared_count==1)
|
|
{
|
|
state.shared_count=0;
|
|
state.exclusive=true;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
#ifdef BOOST_THREAD_USES_CHRONO
|
|
template <class Rep, class Period>
|
|
bool
|
|
try_unlock_shared_and_lock_for(
|
|
const chrono::duration<Rep, Period>& rel_time)
|
|
{
|
|
return try_unlock_shared_and_lock_until(
|
|
chrono::steady_clock::now() + rel_time);
|
|
}
|
|
template <class Clock, class Duration>
|
|
bool
|
|
try_unlock_shared_and_lock_until(
|
|
const chrono::time_point<Clock, Duration>& abs_time)
|
|
{
|
|
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
|
|
boost::this_thread::disable_interruption do_not_disturb;
|
|
#endif
|
|
boost::unique_lock<boost::mutex> lk(state_change);
|
|
state.assert_lock_shared();
|
|
if (state.shared_count != 1)
|
|
{
|
|
for (;;)
|
|
{
|
|
cv_status status = shared_cond.wait_until(lk,abs_time);
|
|
if (state.shared_count == 1)
|
|
break;
|
|
if(status == cv_status::timeout)
|
|
return false;
|
|
}
|
|
}
|
|
state.upgrade=false;
|
|
state.exclusive=true;
|
|
state.exclusive_waiting_blocked=false;
|
|
state.shared_count=0;
|
|
return true;
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
// Shared <-> Upgrade
|
|
void unlock_upgrade_and_lock_shared()
|
|
{
|
|
boost::unique_lock<boost::mutex> lk(state_change);
|
|
state.assert_lock_upgraded();
|
|
state.upgrade=false;
|
|
state.exclusive_waiting_blocked=false;
|
|
release_waiters();
|
|
}
|
|
|
|
#ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS
|
|
bool try_unlock_shared_and_lock_upgrade()
|
|
{
|
|
boost::unique_lock<boost::mutex> lk(state_change);
|
|
state.assert_lock_shared();
|
|
if( !state.exclusive
|
|
&& !state.exclusive_waiting_blocked
|
|
&& !state.upgrade
|
|
)
|
|
{
|
|
state.upgrade=true;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
#ifdef BOOST_THREAD_USES_CHRONO
|
|
template <class Rep, class Period>
|
|
bool
|
|
try_unlock_shared_and_lock_upgrade_for(
|
|
const chrono::duration<Rep, Period>& rel_time)
|
|
{
|
|
return try_unlock_shared_and_lock_upgrade_until(
|
|
chrono::steady_clock::now() + rel_time);
|
|
}
|
|
template <class Clock, class Duration>
|
|
bool
|
|
try_unlock_shared_and_lock_upgrade_until(
|
|
const chrono::time_point<Clock, Duration>& abs_time)
|
|
{
|
|
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
|
|
boost::this_thread::disable_interruption do_not_disturb;
|
|
#endif
|
|
boost::unique_lock<boost::mutex> lk(state_change);
|
|
state.assert_lock_shared();
|
|
if( state.exclusive
|
|
|| state.exclusive_waiting_blocked
|
|
|| state.upgrade
|
|
)
|
|
{
|
|
for (;;)
|
|
{
|
|
cv_status status = exclusive_cond.wait_until(lk,abs_time);
|
|
if( ! state.exclusive
|
|
&& ! state.exclusive_waiting_blocked
|
|
&& ! state.upgrade
|
|
)
|
|
break;
|
|
if(status == cv_status::timeout)
|
|
return false;
|
|
}
|
|
}
|
|
state.upgrade=true;
|
|
return true;
|
|
}
|
|
#endif
|
|
#endif
|
|
};
|
|
|
|
typedef shared_mutex upgrade_mutex;
|
|
}
|
|
|
|
#include <boost/config/abi_suffix.hpp>
|
|
|
|
#endif
|