boost/interprocess/sync/shm/named_condition.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2011. 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)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTERPROCESS_SHM_NAMED_CONDITION_HPP
#define BOOST_INTERPROCESS_SHM_NAMED_CONDITION_HPP
#if (defined _MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/static_assert.hpp>
#include <boost/interprocess/detail/type_traits.hpp>
#include <boost/interprocess/creation_tags.hpp>
#include <boost/interprocess/exceptions.hpp>
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/sync/interprocess_condition.hpp>
#include <boost/interprocess/detail/managed_open_or_create_impl.hpp>
#include <boost/interprocess/detail/posix_time_types_wrk.hpp>
#include <boost/interprocess/sync/shm/named_creation_functor.hpp>
#include <boost/interprocess/sync/named_mutex.hpp>
#include <boost/interprocess/permissions.hpp>
#if defined (BOOST_INTERPROCESS_NAMED_MUTEX_USES_POSIX_SEMAPHORES)
#include <boost/interprocess/sync/interprocess_mutex.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#endif
//!\file
//!Describes process-shared variables interprocess_condition class
namespace boost {
namespace interprocess {
namespace ipcdetail {
/// @cond
class interprocess_tester;
/// @endcond
//! A global condition variable that can be created by name.
//! This condition variable is designed to work with named_mutex and
//! can't be placed in shared memory or memory mapped files.
class shm_named_condition
{
/// @cond
//Non-copyable
shm_named_condition();
shm_named_condition(const shm_named_condition &);
shm_named_condition &operator=(const shm_named_condition &);
/// @endcond
public:
//!Creates a global condition with a name.
//!If the condition can't be created throws interprocess_exception
shm_named_condition(create_only_t create_only, const char *name, const permissions &perm = permissions());
//!Opens or creates a global condition with a name.
//!If the condition is created, this call is equivalent to
//!shm_named_condition(create_only_t, ... )
//!If the condition is already created, this call is equivalent
//!shm_named_condition(open_only_t, ... )
//!Does not throw
shm_named_condition(open_or_create_t open_or_create, const char *name, const permissions &perm = permissions());
//!Opens a global condition with a name if that condition is previously
//!created. If it is not previously created this function throws
//!interprocess_exception.
shm_named_condition(open_only_t open_only, const char *name);
//!Destroys *this and indicates that the calling process is finished using
//!the resource. The destructor function will deallocate
//!any system resources allocated by the system for use by this process for
//!this resource. The resource can still be opened again calling
//!the open constructor overload. To erase the resource from the system
//!use remove().
~shm_named_condition();
//!If there is a thread waiting on *this, change that
//!thread's state to ready. Otherwise there is no effect.*/
void notify_one();
//!Change the state of all threads waiting on *this to ready.
//!If there are no waiting threads, notify_all() has no effect.
void notify_all();
//!Releases the lock on the named_mutex object associated with lock, blocks
//!the current thread of execution until readied by a call to
//!this->notify_one() or this->notify_all(), and then reacquires the lock.
template <typename L>
void wait(L& lock);
//!The same as:
//!while (!pred()) wait(lock)
template <typename L, typename Pr>
void wait(L& lock, Pr pred);
//!Releases the lock on the named_mutex object associated with lock, blocks
//!the current thread of execution until readied by a call to
//!this->notify_one() or this->notify_all(), or until time abs_time is reached,
//!and then reacquires the lock.
//!Returns: false if time abs_time is reached, otherwise true.
template <typename L>
bool timed_wait(L& lock, const boost::posix_time::ptime &abs_time);
//!The same as: while (!pred()) {
//! if (!timed_wait(lock, abs_time)) return pred();
//! } return true;
template <typename L, typename Pr>
bool timed_wait(L& lock, const boost::posix_time::ptime &abs_time, Pr pred);
//!Erases a named condition from the system.
//!Returns false on error. Never throws.
static bool remove(const char *name);
/// @cond
private:
struct condition_holder
{
interprocess_condition cond_;
//If named_mutex is implemented using semaphores
//we need to store an additional mutex
#if defined (BOOST_INTERPROCESS_NAMED_MUTEX_USES_POSIX_SEMAPHORES)
interprocess_mutex mutex_;
#endif
};
interprocess_condition *condition() const
{ return &static_cast<condition_holder*>(m_shmem.get_user_address())->cond_; }
template <class Lock>
class lock_inverter
{
Lock &l_;
public:
lock_inverter(Lock &l)
: l_(l)
{}
void lock() { l_.unlock(); }
void unlock() { l_.lock(); }
};
//If named mutex uses POSIX semaphores, then the shm based condition variable
//must use it's internal lock to wait, as sem_t does not store a pthread_mutex_t
//instance needed by pthread_mutex_cond_t
#if defined (BOOST_INTERPROCESS_NAMED_MUTEX_USES_POSIX_SEMAPHORES)
interprocess_mutex *mutex() const
{ return &static_cast<condition_holder*>(m_shmem.get_user_address())->mutex_; }
template <class Lock>
void do_wait(Lock& lock)
{
//shm_named_condition only works with named_mutex
BOOST_STATIC_ASSERT((is_convertible<typename Lock::mutex_type&, named_mutex&>::value == true));
//lock internal before unlocking external to avoid race with a notifier
scoped_lock<interprocess_mutex> internal_lock(*this->mutex());
lock_inverter<Lock> inverted_lock(lock);
scoped_lock<lock_inverter<Lock> > external_unlock(inverted_lock);
//unlock internal first to avoid deadlock with near simultaneous waits
scoped_lock<interprocess_mutex> internal_unlock;
internal_lock.swap(internal_unlock);
this->condition()->wait(internal_unlock);
}
template <class Lock>
bool do_timed_wait(Lock& lock, const boost::posix_time::ptime &abs_time)
{
//shm_named_condition only works with named_mutex
BOOST_STATIC_ASSERT((is_convertible<typename Lock::mutex_type&, named_mutex&>::value == true));
//lock internal before unlocking external to avoid race with a notifier
scoped_lock<interprocess_mutex> internal_lock(*this->mutex(), abs_time);
if(!internal_lock) return false;
lock_inverter<Lock> inverted_lock(lock);
scoped_lock<lock_inverter<Lock> > external_unlock(inverted_lock);
//unlock internal first to avoid deadlock with near simultaneous waits
scoped_lock<interprocess_mutex> internal_unlock;
internal_lock.swap(internal_unlock);
return this->condition()->timed_wait(internal_unlock, abs_time);
}
#else //defined (BOOST_INTERPROCESS_NAMED_MUTEX_USES_POSIX_SEMAPHORES)
template<class Lock>
class lock_wrapper
{
typedef void (lock_wrapper::*unspecified_bool_type)();
public:
typedef interprocess_mutex mutex_type;
lock_wrapper(Lock &l)
: l_(l)
{}
mutex_type* mutex() const
{ return l_.mutex()->mutex(); }
void lock() { l_.lock(); }
void unlock() { l_.unlock(); }
operator unspecified_bool_type() const
{ return l_ ? &lock_wrapper::lock : 0; }
private:
Lock &l_;
};
#endif //defined (BOOST_INTERPROCESS_NAMED_MUTEX_USES_POSIX_SEMAPHORES)
friend class boost::interprocess::ipcdetail::interprocess_tester;
void dont_close_on_destruction();
managed_open_or_create_impl<shared_memory_object> m_shmem;
template <class T, class Arg> friend class boost::interprocess::ipcdetail::named_creation_functor;
typedef boost::interprocess::ipcdetail::named_creation_functor<condition_holder> construct_func_t;
/// @endcond
};
/// @cond
inline shm_named_condition::~shm_named_condition()
{}
inline shm_named_condition::shm_named_condition(create_only_t, const char *name, const permissions &perm)
: m_shmem (create_only
,name
,sizeof(condition_holder) +
managed_open_or_create_impl<shared_memory_object>::
ManagedOpenOrCreateUserOffset
,read_write
,0
,construct_func_t(DoCreate)
,perm)
{}
inline shm_named_condition::shm_named_condition(open_or_create_t, const char *name, const permissions &perm)
: m_shmem (open_or_create
,name
,sizeof(condition_holder) +
managed_open_or_create_impl<shared_memory_object>::
ManagedOpenOrCreateUserOffset
,read_write
,0
,construct_func_t(DoOpenOrCreate)
,perm)
{}
inline shm_named_condition::shm_named_condition(open_only_t, const char *name)
: m_shmem (open_only
,name
,read_write
,0
,construct_func_t(DoOpen))
{}
inline void shm_named_condition::dont_close_on_destruction()
{ interprocess_tester::dont_close_on_destruction(m_shmem); }
#if defined(BOOST_INTERPROCESS_NAMED_MUTEX_USES_POSIX_SEMAPHORES)
inline void shm_named_condition::notify_one()
{
scoped_lock<interprocess_mutex> internal_lock(*this->mutex());
this->condition()->notify_one();
}
inline void shm_named_condition::notify_all()
{
scoped_lock<interprocess_mutex> internal_lock(*this->mutex());
this->condition()->notify_all();
}
template <typename L>
inline void shm_named_condition::wait(L& lock)
{
if (!lock)
throw lock_exception();
this->do_wait(lock);
}
template <typename L, typename Pr>
inline void shm_named_condition::wait(L& lock, Pr pred)
{
if (!lock)
throw lock_exception();
while (!pred())
this->do_wait(lock);
}
template <typename L>
inline bool shm_named_condition::timed_wait
(L& lock, const boost::posix_time::ptime &abs_time)
{
if(abs_time == boost::posix_time::pos_infin){
this->wait(lock);
return true;
}
if (!lock)
throw lock_exception();
return this->do_timed_wait(lock, abs_time);
}
template <typename L, typename Pr>
inline bool shm_named_condition::timed_wait
(L& lock, const boost::posix_time::ptime &abs_time, Pr pred)
{
if(abs_time == boost::posix_time::pos_infin){
this->wait(lock, pred);
return true;
}
if (!lock)
throw lock_exception();
while (!pred()){
if(!this->do_timed_wait(lock, abs_time)){
return pred();
}
}
return true;
}
#else
inline void shm_named_condition::notify_one()
{ this->condition()->notify_one(); }
inline void shm_named_condition::notify_all()
{ this->condition()->notify_all(); }
template <typename L>
inline void shm_named_condition::wait(L& lock)
{
lock_wrapper<L> newlock(lock);
this->condition()->wait(newlock);
}
template <typename L, typename Pr>
inline void shm_named_condition::wait(L& lock, Pr pred)
{
lock_wrapper<L> newlock(lock);
this->condition()->wait(newlock, pred);
}
template <typename L>
inline bool shm_named_condition::timed_wait
(L& lock, const boost::posix_time::ptime &abs_time)
{
lock_wrapper<L> newlock(lock);
return this->condition()->timed_wait(newlock, abs_time);
}
template <typename L, typename Pr>
inline bool shm_named_condition::timed_wait
(L& lock, const boost::posix_time::ptime &abs_time, Pr pred)
{
lock_wrapper<L> newlock(lock);
return this->condition()->timed_wait(newlock, abs_time, pred);
}
#endif
inline bool shm_named_condition::remove(const char *name)
{ return shared_memory_object::remove(name); }
/// @endcond
} //namespace ipcdetail
} //namespace interprocess
} //namespace boost
#include <boost/interprocess/detail/config_end.hpp>
#endif // BOOST_INTERPROCESS_SHM_NAMED_CONDITION_HPP