| #ifndef BOOST_THREAD_WIN32_SHARED_MUTEX_HPP | |
| #define BOOST_THREAD_WIN32_SHARED_MUTEX_HPP | |
| // (C) Copyright 2006-8 Anthony Williams | |
| // | |
| // Distributed under the Boost Software License, Version 1.0. (See | |
| // accompanying file LICENSE_1_0.txt or copy at | |
| // http://www.boost.org/LICENSE_1_0.txt) | |
| #include <boost/assert.hpp> | |
| #include <boost/detail/interlocked.hpp> | |
| #include <boost/thread/win32/thread_primitives.hpp> | |
| #include <boost/static_assert.hpp> | |
| #include <limits.h> | |
| #include <boost/utility.hpp> | |
| #include <boost/thread/thread_time.hpp> | |
| #include <boost/config/abi_prefix.hpp> | |
| namespace boost | |
| { | |
| class shared_mutex | |
| { | |
| private: | |
| shared_mutex(shared_mutex const&); | |
| shared_mutex& operator=(shared_mutex const&); | |
| private: | |
| struct state_data | |
| { | |
| unsigned shared_count:11, | |
| shared_waiting:11, | |
| exclusive:1, | |
| upgrade:1, | |
| exclusive_waiting:7, | |
| exclusive_waiting_blocked:1; | |
| friend bool operator==(state_data const& lhs,state_data const& rhs) | |
| { | |
| return *reinterpret_cast<unsigned const*>(&lhs)==*reinterpret_cast<unsigned const*>(&rhs); | |
| } | |
| }; | |
| template<typename T> | |
| T interlocked_compare_exchange(T* target,T new_value,T comparand) | |
| { | |
| BOOST_STATIC_ASSERT(sizeof(T)==sizeof(long)); | |
| long const res=BOOST_INTERLOCKED_COMPARE_EXCHANGE(reinterpret_cast<long*>(target), | |
| *reinterpret_cast<long*>(&new_value), | |
| *reinterpret_cast<long*>(&comparand)); | |
| return *reinterpret_cast<T const*>(&res); | |
| } | |
| enum | |
| { | |
| unlock_sem = 0, | |
| exclusive_sem = 1 | |
| }; | |
| state_data state; | |
| detail::win32::handle semaphores[2]; | |
| detail::win32::handle upgrade_sem; | |
| void release_waiters(state_data old_state) | |
| { | |
| if(old_state.exclusive_waiting) | |
| { | |
| BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[exclusive_sem],1,0)!=0); | |
| } | |
| if(old_state.shared_waiting || old_state.exclusive_waiting) | |
| { | |
| BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[unlock_sem],old_state.shared_waiting + (old_state.exclusive_waiting?1:0),0)!=0); | |
| } | |
| } | |
| public: | |
| shared_mutex() | |
| { | |
| semaphores[unlock_sem]=detail::win32::create_anonymous_semaphore(0,LONG_MAX); | |
| semaphores[exclusive_sem]=detail::win32::create_anonymous_semaphore(0,LONG_MAX); | |
| upgrade_sem=detail::win32::create_anonymous_semaphore(0,LONG_MAX); | |
| state_data state_={0}; | |
| state=state_; | |
| } | |
| ~shared_mutex() | |
| { | |
| detail::win32::CloseHandle(upgrade_sem); | |
| detail::win32::CloseHandle(semaphores[unlock_sem]); | |
| detail::win32::CloseHandle(semaphores[exclusive_sem]); | |
| } | |
| bool try_lock_shared() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(!new_state.exclusive && !new_state.exclusive_waiting_blocked) | |
| { | |
| ++new_state.shared_count; | |
| if(!new_state.shared_count) | |
| { | |
| return false; | |
| } | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| return !(old_state.exclusive| old_state.exclusive_waiting_blocked); | |
| } | |
| void lock_shared() | |
| { | |
| BOOST_VERIFY(timed_lock_shared(::boost::detail::get_system_time_sentinel())); | |
| } | |
| template<typename TimeDuration> | |
| bool timed_lock_shared(TimeDuration const & relative_time) | |
| { | |
| return timed_lock_shared(get_system_time()+relative_time); | |
| } | |
| bool timed_lock_shared(boost::system_time const& wait_until) | |
| { | |
| for(;;) | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.exclusive || new_state.exclusive_waiting_blocked) | |
| { | |
| ++new_state.shared_waiting; | |
| if(!new_state.shared_waiting) | |
| { | |
| boost::throw_exception(boost::lock_error()); | |
| } | |
| } | |
| else | |
| { | |
| ++new_state.shared_count; | |
| if(!new_state.shared_count) | |
| { | |
| boost::throw_exception(boost::lock_error()); | |
| } | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| if(!(old_state.exclusive| old_state.exclusive_waiting_blocked)) | |
| { | |
| return true; | |
| } | |
| unsigned long const res=detail::win32::WaitForSingleObject(semaphores[unlock_sem],::boost::detail::get_milliseconds_until(wait_until)); | |
| if(res==detail::win32::timeout) | |
| { | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.exclusive || new_state.exclusive_waiting_blocked) | |
| { | |
| if(new_state.shared_waiting) | |
| { | |
| --new_state.shared_waiting; | |
| } | |
| } | |
| else | |
| { | |
| ++new_state.shared_count; | |
| if(!new_state.shared_count) | |
| { | |
| return false; | |
| } | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| if(!(old_state.exclusive| old_state.exclusive_waiting_blocked)) | |
| { | |
| return true; | |
| } | |
| return false; | |
| } | |
| BOOST_ASSERT(res==0); | |
| } | |
| } | |
| void unlock_shared() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| bool const last_reader=!--new_state.shared_count; | |
| if(last_reader) | |
| { | |
| if(new_state.upgrade) | |
| { | |
| new_state.upgrade=false; | |
| new_state.exclusive=true; | |
| } | |
| else | |
| { | |
| if(new_state.exclusive_waiting) | |
| { | |
| --new_state.exclusive_waiting; | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| new_state.shared_waiting=0; | |
| } | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| if(last_reader) | |
| { | |
| if(old_state.upgrade) | |
| { | |
| BOOST_VERIFY(detail::win32::ReleaseSemaphore(upgrade_sem,1,0)!=0); | |
| } | |
| else | |
| { | |
| release_waiters(old_state); | |
| } | |
| } | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| } | |
| void lock() | |
| { | |
| BOOST_VERIFY(timed_lock(::boost::detail::get_system_time_sentinel())); | |
| } | |
| template<typename TimeDuration> | |
| bool timed_lock(TimeDuration const & relative_time) | |
| { | |
| return timed_lock(get_system_time()+relative_time); | |
| } | |
| bool try_lock() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.shared_count || new_state.exclusive) | |
| { | |
| return false; | |
| } | |
| else | |
| { | |
| new_state.exclusive=true; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| return true; | |
| } | |
| bool timed_lock(boost::system_time const& wait_until) | |
| { | |
| for(;;) | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.shared_count || new_state.exclusive) | |
| { | |
| ++new_state.exclusive_waiting; | |
| if(!new_state.exclusive_waiting) | |
| { | |
| boost::throw_exception(boost::lock_error()); | |
| } | |
| new_state.exclusive_waiting_blocked=true; | |
| } | |
| else | |
| { | |
| new_state.exclusive=true; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| if(!old_state.shared_count && !old_state.exclusive) | |
| { | |
| return true; | |
| } | |
| unsigned long const wait_res=detail::win32::WaitForMultipleObjects(2,semaphores,true,::boost::detail::get_milliseconds_until(wait_until)); | |
| if(wait_res==detail::win32::timeout) | |
| { | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.shared_count || new_state.exclusive) | |
| { | |
| if(new_state.exclusive_waiting) | |
| { | |
| if(!--new_state.exclusive_waiting) | |
| { | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| } | |
| } | |
| else | |
| { | |
| new_state.exclusive=true; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| if(!old_state.shared_count && !old_state.exclusive) | |
| { | |
| return true; | |
| } | |
| return false; | |
| } | |
| BOOST_ASSERT(wait_res<2); | |
| } | |
| } | |
| void unlock() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| new_state.exclusive=false; | |
| if(new_state.exclusive_waiting) | |
| { | |
| --new_state.exclusive_waiting; | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| new_state.shared_waiting=0; | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| release_waiters(old_state); | |
| } | |
| void lock_upgrade() | |
| { | |
| for(;;) | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.exclusive || new_state.exclusive_waiting_blocked || new_state.upgrade) | |
| { | |
| ++new_state.shared_waiting; | |
| if(!new_state.shared_waiting) | |
| { | |
| boost::throw_exception(boost::lock_error()); | |
| } | |
| } | |
| else | |
| { | |
| ++new_state.shared_count; | |
| if(!new_state.shared_count) | |
| { | |
| boost::throw_exception(boost::lock_error()); | |
| } | |
| new_state.upgrade=true; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| if(!(old_state.exclusive|| old_state.exclusive_waiting_blocked|| old_state.upgrade)) | |
| { | |
| return; | |
| } | |
| BOOST_VERIFY(!detail::win32::WaitForSingleObject(semaphores[unlock_sem],detail::win32::infinite)); | |
| } | |
| } | |
| bool try_lock_upgrade() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| if(new_state.exclusive || new_state.exclusive_waiting_blocked || new_state.upgrade) | |
| { | |
| return false; | |
| } | |
| else | |
| { | |
| ++new_state.shared_count; | |
| if(!new_state.shared_count) | |
| { | |
| return false; | |
| } | |
| new_state.upgrade=true; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| return true; | |
| } | |
| void unlock_upgrade() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| new_state.upgrade=false; | |
| bool const last_reader=!--new_state.shared_count; | |
| if(last_reader) | |
| { | |
| if(new_state.exclusive_waiting) | |
| { | |
| --new_state.exclusive_waiting; | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| new_state.shared_waiting=0; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| if(last_reader) | |
| { | |
| release_waiters(old_state); | |
| } | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| } | |
| void unlock_upgrade_and_lock() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| bool const last_reader=!--new_state.shared_count; | |
| if(last_reader) | |
| { | |
| new_state.upgrade=false; | |
| new_state.exclusive=true; | |
| } | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| if(!last_reader) | |
| { | |
| BOOST_VERIFY(!detail::win32::WaitForSingleObject(upgrade_sem,detail::win32::infinite)); | |
| } | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| } | |
| void unlock_and_lock_upgrade() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| new_state.exclusive=false; | |
| new_state.upgrade=true; | |
| ++new_state.shared_count; | |
| if(new_state.exclusive_waiting) | |
| { | |
| --new_state.exclusive_waiting; | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| new_state.shared_waiting=0; | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| release_waiters(old_state); | |
| } | |
| void unlock_and_lock_shared() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| new_state.exclusive=false; | |
| ++new_state.shared_count; | |
| if(new_state.exclusive_waiting) | |
| { | |
| --new_state.exclusive_waiting; | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| new_state.shared_waiting=0; | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| release_waiters(old_state); | |
| } | |
| void unlock_upgrade_and_lock_shared() | |
| { | |
| state_data old_state=state; | |
| for(;;) | |
| { | |
| state_data new_state=old_state; | |
| new_state.upgrade=false; | |
| if(new_state.exclusive_waiting) | |
| { | |
| --new_state.exclusive_waiting; | |
| new_state.exclusive_waiting_blocked=false; | |
| } | |
| new_state.shared_waiting=0; | |
| state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); | |
| if(current_state==old_state) | |
| { | |
| break; | |
| } | |
| old_state=current_state; | |
| } | |
| release_waiters(old_state); | |
| } | |
| }; | |
| } | |
| #include <boost/config/abi_suffix.hpp> | |
| #endif |