| #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 |