904 lines
31 KiB
Plaintext
904 lines
31 KiB
Plaintext
#ifndef BOOST_THREAD_WIN32_SHARED_MUTEX_HPP
|
|
#define BOOST_THREAD_WIN32_SHARED_MUTEX_HPP
|
|
|
|
// (C) Copyright 2006-8 Anthony Williams
|
|
// (C) Copyright 2011-2012 Vicente J. Botet Escriba
|
|
//
|
|
// 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/thread/thread_time.hpp>
|
|
#ifdef BOOST_THREAD_USES_CHRONO
|
|
#include <boost/chrono/system_clocks.hpp>
|
|
#include <boost/chrono/ceil.hpp>
|
|
#endif
|
|
#include <boost/thread/detail/delete.hpp>
|
|
|
|
#include <boost/config/abi_prefix.hpp>
|
|
|
|
namespace boost
|
|
{
|
|
class shared_mutex
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
void release_shared_waiters(state_data old_state)
|
|
{
|
|
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:
|
|
BOOST_THREAD_NO_COPYABLE(shared_mutex)
|
|
shared_mutex()
|
|
{
|
|
semaphores[unlock_sem]=detail::win32::create_anonymous_semaphore(0,LONG_MAX);
|
|
semaphores[exclusive_sem]=detail::win32::create_anonymous_semaphore_nothrow(0,LONG_MAX);
|
|
if (!semaphores[exclusive_sem])
|
|
{
|
|
detail::win32::release_semaphore(semaphores[unlock_sem],LONG_MAX);
|
|
boost::throw_exception(thread_resource_error());
|
|
}
|
|
upgrade_sem=detail::win32::create_anonymous_semaphore_nothrow(0,LONG_MAX);
|
|
if (!upgrade_sem)
|
|
{
|
|
detail::win32::release_semaphore(semaphores[unlock_sem],LONG_MAX);
|
|
detail::win32::release_semaphore(semaphores[exclusive_sem],LONG_MAX);
|
|
boost::throw_exception(thread_resource_error());
|
|
}
|
|
state_data state_={0,0,0,0,0,0};
|
|
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()
|
|
{
|
|
|
|
#if defined BOOST_THREAD_USES_DATETIME
|
|
BOOST_VERIFY(timed_lock_shared(::boost::detail::get_system_time_sentinel()));
|
|
#else
|
|
BOOST_VERIFY(try_lock_shared_until(chrono::steady_clock::now()));
|
|
#endif
|
|
}
|
|
|
|
#if defined BOOST_THREAD_USES_DATETIME
|
|
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::WaitForSingleObjectEx(semaphores[unlock_sem],::boost::detail::get_milliseconds_until(wait_until), 0);
|
|
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);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef BOOST_THREAD_USES_CHRONO
|
|
template <class Rep, class Period>
|
|
bool try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time)
|
|
{
|
|
return try_lock_shared_until(chrono::steady_clock::now() + rel_time);
|
|
}
|
|
template <class Clock, class Duration>
|
|
bool try_lock_shared_until(const chrono::time_point<Clock, Duration>& t)
|
|
{
|
|
using namespace chrono;
|
|
system_clock::time_point s_now = system_clock::now();
|
|
typename Clock::time_point c_now = Clock::now();
|
|
return try_lock_shared_until(s_now + ceil<system_clock::duration>(t - c_now));
|
|
}
|
|
template <class Duration>
|
|
bool try_lock_shared_until(const chrono::time_point<chrono::system_clock, Duration>& t)
|
|
{
|
|
using namespace chrono;
|
|
typedef time_point<chrono::system_clock, chrono::system_clock::duration> sys_tmpt;
|
|
return try_lock_shared_until(sys_tmpt(chrono::ceil<chrono::system_clock::duration>(t.time_since_epoch())));
|
|
}
|
|
bool try_lock_shared_until(const chrono::time_point<chrono::system_clock, chrono::system_clock::duration>& tp)
|
|
{
|
|
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;
|
|
}
|
|
|
|
chrono::system_clock::time_point n = chrono::system_clock::now();
|
|
unsigned long res;
|
|
if (tp>n) {
|
|
chrono::milliseconds rel_time= chrono::ceil<chrono::milliseconds>(tp-n);
|
|
res=detail::win32::WaitForSingleObjectEx(semaphores[unlock_sem],
|
|
static_cast<unsigned long>(rel_time.count()), 0);
|
|
} else {
|
|
res=detail::win32::timeout;
|
|
}
|
|
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);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
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()
|
|
{
|
|
|
|
#if defined BOOST_THREAD_USES_DATETIME
|
|
BOOST_VERIFY(timed_lock(::boost::detail::get_system_time_sentinel()));
|
|
#else
|
|
BOOST_VERIFY(try_lock_until(chrono::steady_clock::now()));
|
|
#endif
|
|
}
|
|
|
|
#if defined BOOST_THREAD_USES_DATETIME
|
|
template<typename TimeDuration>
|
|
bool timed_lock(TimeDuration const & relative_time)
|
|
{
|
|
return timed_lock(get_system_time()+relative_time);
|
|
}
|
|
#endif
|
|
|
|
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;
|
|
}
|
|
|
|
|
|
#if defined BOOST_THREAD_USES_DATETIME
|
|
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;
|
|
}
|
|
#ifndef UNDER_CE
|
|
const bool wait_all = true;
|
|
#else
|
|
const bool wait_all = false;
|
|
#endif
|
|
unsigned long const wait_res=detail::win32::WaitForMultipleObjectsEx(2,semaphores,wait_all,::boost::detail::get_milliseconds_until(wait_until), 0);
|
|
if(wait_res==detail::win32::timeout)
|
|
{
|
|
for(;;)
|
|
{
|
|
bool must_notify = false;
|
|
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;
|
|
must_notify = true;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
new_state.exclusive=true;
|
|
}
|
|
|
|
state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state);
|
|
if (must_notify)
|
|
{
|
|
BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[unlock_sem],1,0)!=0);
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
#endif
|
|
#ifdef BOOST_THREAD_USES_CHRONO
|
|
template <class Rep, class Period>
|
|
bool try_lock_for(const chrono::duration<Rep, Period>& rel_time)
|
|
{
|
|
return try_lock_until(chrono::steady_clock::now() + rel_time);
|
|
}
|
|
template <class Clock, class Duration>
|
|
bool try_lock_until(const chrono::time_point<Clock, Duration>& t)
|
|
{
|
|
using namespace chrono;
|
|
system_clock::time_point s_now = system_clock::now();
|
|
typename Clock::time_point c_now = Clock::now();
|
|
return try_lock_until(s_now + ceil<system_clock::duration>(t - c_now));
|
|
}
|
|
template <class Duration>
|
|
bool try_lock_until(const chrono::time_point<chrono::system_clock, Duration>& t)
|
|
{
|
|
using namespace chrono;
|
|
typedef time_point<chrono::system_clock, chrono::system_clock::duration> sys_tmpt;
|
|
return try_lock_until(sys_tmpt(chrono::ceil<chrono::system_clock::duration>(t.time_since_epoch())));
|
|
}
|
|
bool try_lock_until(const chrono::time_point<chrono::system_clock, chrono::system_clock::duration>& tp)
|
|
{
|
|
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;
|
|
}
|
|
#ifndef UNDER_CE
|
|
const bool wait_all = true;
|
|
#else
|
|
const bool wait_all = false;
|
|
#endif
|
|
|
|
chrono::system_clock::time_point n = chrono::system_clock::now();
|
|
unsigned long wait_res;
|
|
if (tp>n) {
|
|
chrono::milliseconds rel_time= chrono::ceil<chrono::milliseconds>(tp-chrono::system_clock::now());
|
|
wait_res=detail::win32::WaitForMultipleObjectsEx(2,semaphores,wait_all,
|
|
static_cast<unsigned long>(rel_time.count()), 0);
|
|
} else {
|
|
wait_res=detail::win32::timeout;
|
|
}
|
|
if(wait_res==detail::win32::timeout)
|
|
{
|
|
for(;;)
|
|
{
|
|
bool must_notify = false;
|
|
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;
|
|
must_notify = true;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
new_state.exclusive=true;
|
|
}
|
|
|
|
state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state);
|
|
if (must_notify)
|
|
{
|
|
BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[unlock_sem],1,0)!=0);
|
|
}
|
|
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);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
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::WaitForSingleObjectEx(semaphores[unlock_sem],detail::win32::infinite, 0));
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
new_state.shared_waiting=0;
|
|
if(last_reader)
|
|
{
|
|
if(new_state.exclusive_waiting)
|
|
{
|
|
--new_state.exclusive_waiting;
|
|
new_state.exclusive_waiting_blocked=false;
|
|
}
|
|
}
|
|
|
|
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);
|
|
}
|
|
else {
|
|
release_shared_waiters(old_state);
|
|
}
|
|
// #7720
|
|
//else {
|
|
// 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::WaitForSingleObjectEx(upgrade_sem,detail::win32::infinite, 0));
|
|
}
|
|
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);
|
|
}
|
|
// bool try_unlock_upgrade_and_lock()
|
|
// {
|
|
// return false;
|
|
// }
|
|
//#ifdef BOOST_THREAD_USES_CHRONO
|
|
// template <class Rep, class Period>
|
|
// bool
|
|
// try_unlock_upgrade_and_lock_for(
|
|
// const chrono::duration<Rep, Period>& rel_time)
|
|
// {
|
|
// return try_unlock_upgrade_and_lock_until(
|
|
// chrono::steady_clock::now() + rel_time);
|
|
// }
|
|
// template <class Clock, class Duration>
|
|
// bool
|
|
// try_unlock_upgrade_and_lock_until(
|
|
// const chrono::time_point<Clock, Duration>& abs_time)
|
|
// {
|
|
// return false;
|
|
// }
|
|
//#endif
|
|
|
|
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);
|
|
}
|
|
|
|
};
|
|
typedef shared_mutex upgrade_mutex;
|
|
|
|
}
|
|
|
|
#include <boost/config/abi_suffix.hpp>
|
|
|
|
#endif
|