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/***************************************************************************
* lib/io/request_with_waiters.cpp
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2002 Roman Dementiev <dementiev@mpi-sb.mpg.de>
* Copyright (C) 2008 Andreas Beckmann <beckmann@cs.uni-frankfurt.de>
*
* 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 <stxxl/bits/common/mutex.h>
#include <stxxl/bits/common/onoff_switch.h>
#include <stxxl/bits/io/request_with_waiters.h>
#include <stxxl/bits/parallel.h>
#include <algorithm>
#include <functional>
STXXL_BEGIN_NAMESPACE
bool request_with_waiters::add_waiter(onoff_switch* sw)
{
// this lock needs to be obtained before poll(), otherwise a race
// condition might occur: the state might change and notify_waiters()
// could be called between poll() and insert() resulting in waiter sw
// never being notified
scoped_mutex_lock lock(m_waiters_mutex);
if (poll()) // request already finished
{
return true;
}
m_waiters.insert(sw);
return false;
}
void request_with_waiters::delete_waiter(onoff_switch* sw)
{
scoped_mutex_lock lock(m_waiters_mutex);
m_waiters.erase(sw);
}
void request_with_waiters::notify_waiters()
{
scoped_mutex_lock lock(m_waiters_mutex);
std::for_each(m_waiters.begin(),
m_waiters.end(),
std::mem_fun(&onoff_switch::on)
_STXXL_FORCE_SEQUENTIAL);
}
size_t request_with_waiters::num_waiters()
{
scoped_mutex_lock lock(m_waiters_mutex);
return m_waiters.size();
}
STXXL_END_NAMESPACE
// vim: et:ts=4:sw=4
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