/*!
* The callback for less relation filter
*/
virtual filter on_less_relation(attribute_name const& name, string_type const& arg)
{
BOOST_LOG_THROW_DESCR_PARAMS(parse_error, "The less attribute value relation is not supported", (name));
BOOST_LOG_UNREACHABLE_RETURN(filter());
}
//! Finds or creates a semaphore with zero counter
interprocess_condition_variable::semaphore_info* interprocess_condition_variable::get_unused_semaphore()
{
// Be optimistic, check the current semaphore first
if (m_current_semaphore && m_current_semaphore->m_semaphore.is_zero_count())
{
mark_unused(*m_current_semaphore);
return m_current_semaphore;
}
const tick_count_clock::time_point now = tick_count_clock::now();
semaphore_info_list::iterator it = m_semaphore_info_list.begin(), end = m_semaphore_info_list.end();
while (it != end)
{
if (is_overflow_less(m_next_semaphore_id, it->m_id) || m_next_semaphore_id == it->m_id)
m_next_semaphore_id = it->m_id + 1u;
if (it->m_semaphore.is_zero_count())
{
semaphore_info& info = *it;
mark_unused(info);
return &info;
}
else if (it->check_non_zero_timeout(now))
{
// The semaphore is non-zero for too long. A blocked process must have crashed. Close it.
m_semaphore_info_set.erase(m_semaphore_info_set.iterator_to(*it));
m_semaphore_info_list.erase_and_dispose(it++, boost::checked_deleter< semaphore_info >());
}
else
{
++it;
}
}
// No semaphore found, create a new one
for (uint32_t semaphore_id = m_next_semaphore_id, semaphore_id_end = semaphore_id - 1u; semaphore_id != semaphore_id_end; ++semaphore_id)
{
interprocess_semaphore sem;
try
{
generate_semaphore_name(semaphore_id);
sem.create_or_open(m_semaphore_name.c_str(), m_perms);
if (!sem.is_zero_count())
continue;
}
catch (...)
{
// Ignore errors, try the next one
continue;
}
semaphore_info* p = NULL;
semaphore_info_set::insert_commit_data insert_state;
std::pair< semaphore_info_set::iterator, bool > res = m_semaphore_info_set.insert_check(semaphore_id, semaphore_info::order_by_id(), insert_state);
if (res.second)
{
p = new semaphore_info(semaphore_id);
p->m_semaphore.swap(sem);
res.first = m_semaphore_info_set.insert_commit(*p, insert_state);
m_semaphore_info_list.push_back(*p);
}
else
{
// Some of our currently open semaphores must have been released by another thread
p = &*res.first;
mark_unused(*p);
}
m_next_semaphore_id = semaphore_id + 1u;
return p;
}
BOOST_LOG_THROW_DESCR(limitation_error, "Too many semaphores are actively used for an interprocess condition variable");
BOOST_LOG_UNREACHABLE_RETURN(NULL);
}
/*!
* The callback for custom relation filter
*/
virtual filter on_custom_relation(attribute_name const& name, string_type const& rel, string_type const& arg)
{
BOOST_LOG_THROW_DESCR_PARAMS(parse_error, "The custom attribute value relation \"" + boost::log::aux::to_narrow(arg) + "\" is not supported", (name));
BOOST_LOG_UNREACHABLE_RETURN(filter());
}
