boost/signals/trackable.hpp
// Boost.Signals library
// Copyright Douglas Gregor 2001-2004. 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_SIGNALS_TRACKABLE_HPP
#define BOOST_SIGNALS_TRACKABLE_HPP
#include <boost/type_traits.hpp>
#include <boost/signals/connection.hpp>
#include <boost/ref.hpp>
#include <boost/utility/addressof.hpp>
#include <list>
#include <vector>
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_PREFIX
#endif
namespace boost {
namespace BOOST_SIGNALS_NAMESPACE {
// Base class for "trackable" objects that can be tracked when they are
// bound in slot target functions. When a trackable object is destroyed,
// the signal/slot connections are disconnected automatically.
class BOOST_SIGNALS_DECL trackable {
private:
static void signal_disconnected(void* obj, void* data);
friend class detail::signal_base_impl;
friend class detail::slot_base;
void signal_connected(connection, BOOST_SIGNALS_NAMESPACE::detail::bound_object&) const;
protected:
trackable() : connected_signals(), dying(false) {}
trackable(const trackable&) : connected_signals(), dying(false) {}
~trackable();
trackable& operator=(const trackable&)
{
dying = true;
connected_signals.clear();
dying = false;
return *this;
}
private:
typedef std::list<connection> connection_list;
typedef connection_list::iterator connection_iterator;
// List of connections that this object is part of
mutable connection_list connected_signals;
// True when the object is being destroyed
mutable bool dying;
};
namespace detail {
template<bool Cond> struct truth {};
// A visitor that adds each trackable object to a vector
class bound_objects_visitor {
public:
bound_objects_visitor(std::vector<const trackable*>& v) :
bound_objects(v)
{
}
template<typename T>
void operator()(const T& t) const
{
decode(t, 0);
}
private:
// decode() decides between a reference wrapper and anything else
template<typename T>
void decode(const reference_wrapper<T>& t, int) const
{
add_if_trackable(t.get_pointer());
}
template<typename T>
void decode(const T& t, long) const
{
typedef truth<(is_pointer<T>::value)> is_a_pointer;
maybe_get_pointer(t, is_a_pointer());
}
// maybe_get_pointer() decides between a pointer and a non-pointer
template<typename T>
void maybe_get_pointer(const T& t, truth<true>) const
{
add_if_trackable(t);
}
template<typename T>
void maybe_get_pointer(const T& t, truth<false>) const
{
// Take the address of this object, because the object itself may be
// trackable
add_if_trackable(boost::addressof(t));
}
// add_if_trackable() adds trackable objects to the list of bound objects
inline void add_if_trackable(const trackable* b) const
{
if (b) {
bound_objects.push_back(b);
}
}
inline void add_if_trackable(const void*) const { }
template<typename R>
inline void add_if_trackable(R (*)()) const { }
template<typename R, typename T1>
inline void add_if_trackable(R (*)(T1)) const { }
template<typename R, typename T1, typename T2>
inline void add_if_trackable(R (*)(T1, T2)) const { }
template<typename R, typename T1, typename T2, typename T3>
inline void add_if_trackable(R (*)(T1, T2, T3)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4>
inline void add_if_trackable(R (*)(T1, T2, T3, T4)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4,
typename T5>
inline void add_if_trackable(R (*)(T1, T2, T3, T4, T5)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4,
typename T5, typename T6>
inline void add_if_trackable(R (*)(T1, T2, T3, T4, T5, T6)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4,
typename T5, typename T6, typename T7>
inline void add_if_trackable(R (*)(T1, T2, T3, T4, T5, T6, T7)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4,
typename T5, typename T6, typename T7, typename T8>
inline void
add_if_trackable(R (*)(T1, T2, T3, T4, T5, T6, T7, T8)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4,
typename T5, typename T6, typename T7, typename T8, typename T9>
inline void
add_if_trackable(R (*)(T1, T2, T3, T4, T5, T6, T7, T8, T9)) const { }
template<typename R, typename T1, typename T2, typename T3, typename T4,
typename T5, typename T6, typename T7, typename T8, typename T9,
typename T10>
inline void
add_if_trackable(R (*)(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10)) const { }
std::vector<const trackable*>& bound_objects;
};
} // end namespace detail
} // end namespace BOOST_SIGNALS_NAMESPACE
} // end namespace boost
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_SUFFIX
#endif
#endif // BOOST_SIGNALS_TRACKABLE_HPP