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#ifndef BOOST_THREAD_PTHREAD_SHARED_MUTEX_HPP
#define BOOST_THREAD_PTHREAD_SHARED_MUTEX_HPP
// (C) Copyright 2006-8 Anthony Williams
// (C) Copyright 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/bind.hpp>
#include <boost/static_assert.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/condition_variable.hpp>
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
#include <boost/thread/detail/thread_interruption.hpp>
#endif
#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:
class state_data
{
public:
state_data () :
shared_count(0),
exclusive(false),
upgrade(false),
exclusive_waiting_blocked(false)
{}
void assert_free() const
{
BOOST_ASSERT( ! exclusive );
BOOST_ASSERT( ! upgrade );
BOOST_ASSERT( shared_count==0 );
}
void assert_locked() const
{
BOOST_ASSERT( exclusive );
BOOST_ASSERT( shared_count==0 );
BOOST_ASSERT( ! upgrade );
}
void assert_lock_shared () const
{
BOOST_ASSERT( ! exclusive );
BOOST_ASSERT( shared_count>0 );
//BOOST_ASSERT( (! upgrade) || (shared_count>1));
// if upgraded there are at least 2 threads sharing the mutex,
// except when unlock_upgrade_and_lock has decreased the number of readers but has not taken yet exclusive ownership.
}
void assert_lock_upgraded () const
{
BOOST_ASSERT( ! exclusive );
BOOST_ASSERT( upgrade );
BOOST_ASSERT( shared_count>0 );
}
void assert_lock_not_upgraded () const
{
BOOST_ASSERT( ! upgrade );
}
bool can_lock () const
{
return ! (shared_count || exclusive);
}
void lock ()
{
exclusive = true;
}
void unlock ()
{
exclusive = false;
exclusive_waiting_blocked = false;
}
bool can_lock_shared () const
{
return ! (exclusive || exclusive_waiting_blocked);
}
bool no_shared () const
{
return shared_count==0;
}
bool one_shared () const
{
return shared_count==1;
}
void lock_shared ()
{
++shared_count;
}
void unlock_shared ()
{
--shared_count;
}
void lock_upgrade ()
{
++shared_count;
upgrade=true;
}
bool can_lock_upgrade () const
{
return ! (exclusive || exclusive_waiting_blocked || upgrade);
}
void unlock_upgrade ()
{
upgrade=false;
--shared_count;
}
//private:
unsigned shared_count;
bool exclusive;
bool upgrade;
bool exclusive_waiting_blocked;
};
state_data state;
boost::mutex state_change;
boost::condition_variable shared_cond;
boost::condition_variable exclusive_cond;
boost::condition_variable upgrade_cond;
void release_waiters()
{
exclusive_cond.notify_one();
shared_cond.notify_all();
}
public:
BOOST_THREAD_NO_COPYABLE(shared_mutex)
shared_mutex()
{
}
~shared_mutex()
{
}
void lock_shared()
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
shared_cond.wait(lk, boost::bind(&state_data::can_lock_shared, boost::ref(state)));
state.lock_shared();
}
bool try_lock_shared()
{
boost::unique_lock<boost::mutex> lk(state_change);
if(!state.can_lock_shared())
{
return false;
}
state.lock_shared();
return true;
}
#if defined BOOST_THREAD_USES_DATETIME
bool timed_lock_shared(system_time const& timeout)
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
if(!shared_cond.timed_wait(lk, timeout, boost::bind(&state_data::can_lock_shared, boost::ref(state))))
{
return false;
}
state.lock_shared();
return true;
}
template<typename TimeDuration>
bool timed_lock_shared(TimeDuration const & relative_time)
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
if(!shared_cond.timed_wait(lk, relative_time, boost::bind(&state_data::can_lock_shared, boost::ref(state))))
{
return false;
}
state.lock_shared();
return true;
}
#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>& 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);
if(!shared_cond.wait_until(lk, abs_time, boost::bind(&state_data::can_lock_shared, boost::ref(state))))
{
return false;
}
state.lock_shared();
return true;
}
#endif
void unlock_shared()
{
boost::unique_lock<boost::mutex> lk(state_change);
state.assert_lock_shared();
state.unlock_shared();
if (state.no_shared())
{
if (state.upgrade)
{
// As there is a thread doing a unlock_upgrade_and_lock that is waiting for state.no_shared()
// avoid other threads to lock, lock_upgrade or lock_shared, so only this thread is notified.
state.upgrade=false;
state.exclusive=true;
//lk.unlock();
upgrade_cond.notify_one();
}
else
{
state.exclusive_waiting_blocked=false;
//lk.unlock();
}
release_waiters();
}
}
void lock()
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
state.exclusive_waiting_blocked=true;
exclusive_cond.wait(lk, boost::bind(&state_data::can_lock, boost::ref(state)));
state.exclusive=true;
}
#if defined BOOST_THREAD_USES_DATETIME
bool timed_lock(system_time const& timeout)
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
state.exclusive_waiting_blocked=true;
if(!exclusive_cond.timed_wait(lk, timeout, boost::bind(&state_data::can_lock, boost::ref(state))))
{
state.exclusive_waiting_blocked=false;
release_waiters();
return false;
}
state.exclusive=true;
return true;
}
template<typename TimeDuration>
bool timed_lock(TimeDuration const & relative_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.exclusive_waiting_blocked=true;
if(!exclusive_cond.timed_wait(lk, relative_time, boost::bind(&state_data::can_lock, boost::ref(state))))
{
state.exclusive_waiting_blocked=false;
release_waiters();
return false;
}
state.exclusive=true;
return true;
}
#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>& 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.exclusive_waiting_blocked=true;
if(!exclusive_cond.wait_until(lk, abs_time, boost::bind(&state_data::can_lock, boost::ref(state))))
{
state.exclusive_waiting_blocked=false;
release_waiters();
return false;
}
state.exclusive=true;
return true;
}
#endif
bool try_lock()
{
boost::unique_lock<boost::mutex> lk(state_change);
if(!state.can_lock())
{
return false;
}
state.exclusive=true;
return true;
}
void unlock()
{
boost::unique_lock<boost::mutex> lk(state_change);
state.assert_locked();
state.exclusive=false;
state.exclusive_waiting_blocked=false;
state.assert_free();
release_waiters();
}
void lock_upgrade()
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
shared_cond.wait(lk, boost::bind(&state_data::can_lock_upgrade, boost::ref(state)));
state.lock_shared();
state.upgrade=true;
}
#if defined BOOST_THREAD_USES_DATETIME
bool timed_lock_upgrade(system_time const& timeout)
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
if(!shared_cond.timed_wait(lk, timeout, boost::bind(&state_data::can_lock_upgrade, boost::ref(state))))
{
return false;
}
state.lock_shared();
state.upgrade=true;
return true;
}
template<typename TimeDuration>
bool timed_lock_upgrade(TimeDuration const & relative_time)
{
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
boost::this_thread::disable_interruption do_not_disturb;
#endif
boost::unique_lock<boost::mutex> lk(state_change);
if(!shared_cond.timed_wait(lk, relative_time, boost::bind(&state_data::can_lock_upgrade, boost::ref(state))))
{
return false;
}
state.lock_shared();
state.upgrade=true;
return true;
}
#endif
#ifdef BOOST_THREAD_USES_CHRONO
template <class Rep, class Period>
bool try_lock_upgrade_for(const chrono::duration<Rep, Period>& rel_time)
{
return try_lock_upgrade_until(chrono::steady_clock::now() + rel_time);
}
template <class Clock, class Duration>
bool try_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);
if(!shared_cond.wait_until(lk, abs_time, boost::bind(&state_data::can_lock_upgrade, boost::ref(state))))
{
return false;
}
state.lock_shared();
state.upgrade=true;
return true;
}
#endif
bool try_lock_upgrade()
{
boost::unique_lock<boost::mutex> lk(state_change);
if(!state.can_lock_upgrade())
{
return false;
}
state.lock_shared();
state.upgrade=true;
state.assert_lock_upgraded();
return true;
}
void unlock_upgrade()
{
boost::unique_lock<boost::mutex> lk(state_change);
//state.upgrade=false;
state.unlock_upgrade();
if(state.no_shared())
{
state.exclusive_waiting_blocked=false;
release_waiters();
} else {
shared_cond.notify_all();
}
}
// Upgrade <-> Exclusive
void unlock_upgrade_and_lock()
{
#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_upgraded();
state.unlock_shared();
upgrade_cond.wait(lk, boost::bind(&state_data::no_shared, boost::ref(state)));
state.upgrade=false;
state.exclusive=true;
state.assert_locked();
}
void unlock_and_lock_upgrade()
{
boost::unique_lock<boost::mutex> lk(state_change);
state.assert_locked();
state.exclusive=false;
state.upgrade=true;
state.lock_shared();
state.exclusive_waiting_blocked=false;
state.assert_lock_upgraded();
release_waiters();
}
bool try_unlock_upgrade_and_lock()
{
boost::unique_lock<boost::mutex> lk(state_change);
state.assert_lock_upgraded();
if( !state.exclusive
&& !state.exclusive_waiting_blocked
&& state.upgrade
&& state.shared_count==1)
{
state.shared_count=0;
state.exclusive=true;
state.upgrade=false;
state.assert_locked();
return true;
}
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)
{
#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_upgraded();
if(!shared_cond.wait_until(lk, abs_time, boost::bind(&state_data::one_shared, boost::ref(state))))
{
return false;
}
state.upgrade=false;
state.exclusive=true;
state.exclusive_waiting_blocked=false;
state.shared_count=0;
return true;
}
#endif
// Shared <-> Exclusive
void unlock_and_lock_shared()
{
boost::unique_lock<boost::mutex> lk(state_change);
state.assert_locked();
state.exclusive=false;
state.lock_shared();
state.exclusive_waiting_blocked=false;
release_waiters();
}
#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(!shared_cond.wait_until(lk, abs_time, boost::bind(&state_data::one_shared, boost::ref(state))))
{
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.can_lock_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(!exclusive_cond.wait_until(lk, abs_time, boost::bind(&state_data::can_lock_upgrade, boost::ref(state))))
{
return false;
}
state.upgrade=true;
return true;
}
#endif
#endif
};
typedef shared_mutex upgrade_mutex;
}
#include <boost/config/abi_suffix.hpp>
#endif
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