552 lines
16 KiB
C++
552 lines
16 KiB
C++
#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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#include <boost/thread/detail/thread_interruption.hpp>
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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/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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struct state_data
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{
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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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state_data state_={0,0,0,0};
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state=state_;
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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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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while(state.exclusive || state.exclusive_waiting_blocked)
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{
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shared_cond.wait(lk);
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}
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++state.shared_count;
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}
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bool try_lock_shared()
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{
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boost::mutex::scoped_lock lk(state_change);
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if(state.exclusive || state.exclusive_waiting_blocked)
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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.shared_count;
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return true;
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}
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}
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bool timed_lock_shared(system_time const& timeout)
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{
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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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while(state.exclusive || state.exclusive_waiting_blocked)
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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.shared_count;
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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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#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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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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.shared_count;
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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::mutex::scoped_lock lk(state_change);
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bool const last_reader=!--state.shared_count;
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if(last_reader)
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{
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if(state.upgrade)
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{
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state.upgrade=false;
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state.exclusive=true;
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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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}
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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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock 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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bool timed_lock(system_time const& timeout)
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{
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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock 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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#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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock 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::mutex::scoped_lock 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::mutex::scoped_lock lk(state_change);
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state.exclusive=false;
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state.exclusive_waiting_blocked=false;
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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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock 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.shared_count;
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state.upgrade=true;
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}
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bool timed_lock_upgrade(system_time const& timeout)
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{
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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock 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.shared_count;
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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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#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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock 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.shared_count;
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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::mutex::scoped_lock 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.shared_count;
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state.upgrade=true;
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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::mutex::scoped_lock lk(state_change);
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state.upgrade=false;
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bool const last_reader=!--state.shared_count;
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if(last_reader)
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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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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--state.shared_count;
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while(state.shared_count)
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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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}
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void unlock_and_lock_upgrade()
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{
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boost::mutex::scoped_lock lk(state_change);
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state.exclusive=false;
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state.upgrade=true;
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++state.shared_count;
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state.exclusive_waiting_blocked=false;
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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::mutex::scoped_lock lk(state_change);
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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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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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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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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::mutex::scoped_lock lk(state_change);
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state.exclusive=false;
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++state.shared_count;
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state.exclusive_waiting_blocked=false;
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release_waiters();
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}
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#ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS
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bool try_unlock_shared_and_lock()
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{
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boost::mutex::scoped_lock lk(state_change);
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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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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_shared_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_shared_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_shared_and_lock_until(
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const chrono::time_point<Clock, Duration>& abs_time)
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{
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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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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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#endif
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// Shared <-> Upgrade
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void unlock_upgrade_and_lock_shared()
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{
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boost::mutex::scoped_lock lk(state_change);
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state.upgrade=false;
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state.exclusive_waiting_blocked=false;
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release_waiters();
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}
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#ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS
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bool try_unlock_shared_and_lock_upgrade()
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{
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boost::mutex::scoped_lock lk(state_change);
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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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)
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{
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state.upgrade=true;
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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_shared_and_lock_upgrade_for(
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const chrono::duration<Rep, Period>& rel_time)
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{
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return try_unlock_shared_and_lock_upgrade_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_shared_and_lock_upgrade_until(
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const chrono::time_point<Clock, Duration>& abs_time)
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{
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boost::this_thread::disable_interruption do_not_disturb;
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boost::mutex::scoped_lock lk(state_change);
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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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)
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{
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for (;;)
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{
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cv_status status = exclusive_cond.wait_until(lk,abs_time);
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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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)
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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=true;
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return true;
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}
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#endif
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#endif
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};
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typedef shared_mutex upgrade_mutex;
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}
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#include <boost/config/abi_suffix.hpp>
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#endif
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