boost/signals2/detail/slot_call_iterator.hpp
// Boost.Signals2 library
// Copyright Douglas Gregor 2001-2004.
// Copyright Frank Mori Hess 2007-2008.
// Use, modification and
// distribution is subject to 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)
// For more information, see http://www.boost.org
#ifndef BOOST_SIGNALS2_SLOT_CALL_ITERATOR_HPP
#define BOOST_SIGNALS2_SLOT_CALL_ITERATOR_HPP
#include <boost/assert.hpp>
#include <boost/aligned_storage.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/optional.hpp>
#include <boost/scoped_ptr.hpp>
#include <boost/signals2/connection.hpp>
#include <boost/signals2/slot_base.hpp>
#include <boost/signals2/detail/auto_buffer.hpp>
#include <boost/signals2/detail/unique_lock.hpp>
#include <boost/weak_ptr.hpp>
namespace boost {
namespace signals2 {
namespace detail {
template<typename ResultType, typename Function>
class slot_call_iterator_cache
{
public:
slot_call_iterator_cache(const Function &f):
f(f),
connected_slot_count(0),
disconnected_slot_count(0)
{}
optional<ResultType> result;
typedef auto_buffer<boost::shared_ptr<void>, store_n_objects<10> > tracked_ptrs_type;
tracked_ptrs_type tracked_ptrs;
Function f;
unsigned connected_slot_count;
unsigned disconnected_slot_count;
};
// Generates a slot call iterator. Essentially, this is an iterator that:
// - skips over disconnected slots in the underlying list
// - calls the connected slots when dereferenced
// - caches the result of calling the slots
template<typename Function, typename Iterator, typename ConnectionBody>
class slot_call_iterator_t
: public boost::iterator_facade<slot_call_iterator_t<Function, Iterator, ConnectionBody>,
typename Function::result_type,
boost::single_pass_traversal_tag,
typename Function::result_type const&>
{
typedef boost::iterator_facade<slot_call_iterator_t<Function, Iterator, ConnectionBody>,
typename Function::result_type,
boost::single_pass_traversal_tag,
typename Function::result_type const&>
inherited;
typedef typename Function::result_type result_type;
friend class boost::iterator_core_access;
public:
slot_call_iterator_t(Iterator iter_in, Iterator end_in,
slot_call_iterator_cache<result_type, Function> &c):
iter(iter_in), end(end_in),
cache(&c), callable_iter(end_in)
{
lock_next_callable();
}
typename inherited::reference
dereference() const
{
if (!cache->result) {
try
{
cache->result.reset(cache->f(*iter));
}
catch(expired_slot &)
{
(*iter)->disconnect();
throw;
}
}
return cache->result.get();
}
void increment()
{
++iter;
lock_next_callable();
cache->result.reset();
}
bool equal(const slot_call_iterator_t& other) const
{
return iter == other.iter;
}
private:
typedef unique_lock<connection_body_base> lock_type;
void lock_next_callable() const
{
if(iter == callable_iter)
{
return;
}
for(;iter != end; ++iter)
{
lock_type lock(**iter);
cache->tracked_ptrs.clear();
(*iter)->nolock_grab_tracked_objects(std::back_inserter(cache->tracked_ptrs));
if((*iter)->nolock_nograb_connected())
{
++cache->connected_slot_count;
}else
{
++cache->disconnected_slot_count;
}
if((*iter)->nolock_nograb_blocked() == false)
{
callable_iter = iter;
break;
}
}
if(iter == end)
{
callable_iter = end;
}
}
mutable Iterator iter;
Iterator end;
slot_call_iterator_cache<result_type, Function> *cache;
mutable Iterator callable_iter;
};
} // end namespace detail
} // end namespace BOOST_SIGNALS_NAMESPACE
} // end namespace boost
#endif // BOOST_SIGNALS2_SLOT_CALL_ITERATOR_HPP