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/*
* Copyright 2002, The libsigc++ Development Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#ifndef _SIGC_TRACKABLE_HPP_
#define _SIGC_TRACKABLE_HPP_
#include <list>
#include <sigc++config.h>
namespace sigc {
namespace internal {
typedef void* (*func_destroy_notify) (void* data);
/** Destroy notification callback.
* A destroy notification callback consists of a data pointer and a
* function pointer. The function is executed from the owning callback
* list (of type sigc::internal::trackable_callback_list) when its parent
* object (of type sigc::trackable) is destroyed or overwritten.
*/
struct SIGC_API trackable_callback
{
void* data_;
func_destroy_notify func_;
trackable_callback(void* data, func_destroy_notify func) noexcept
: data_(data), func_(func) {}
};
/** Callback list.
* A callback list holds an STL list of callbacks of type
* trackable_callback. Callbacks are added and removed with
* add_callback(), remove_callback() and clear(). The callbacks
* are invoked from clear() and from the destructor.
*/
struct SIGC_API trackable_callback_list
{
/** Add a callback function.
* @param data Data that will be sent as a parameter to teh callback function.
* @param func The callback function.
*
*/
void add_callback(void* data, func_destroy_notify func);
/** Remove the callback which has this data associated with it.
* @param data The data that was given as a parameter to add_callback().
*/
void remove_callback(void* data);
/** This invokes all of the callback functions.
*/
void clear();
trackable_callback_list()
: clearing_(false) {}
trackable_callback_list(const trackable_callback_list& src) = delete;
trackable_callback_list& operator=(const trackable_callback_list& src) = delete;
trackable_callback_list(trackable_callback_list&& src) = delete;
trackable_callback_list& operator=(trackable_callback_list&& src) = delete;
/** This invokes all of the callback functions.
*/
~trackable_callback_list();
private:
typedef std::list<trackable_callback> callback_list;
callback_list callbacks_;
bool clearing_;
};
} /* namespace internal */
/** Base class for objects with auto-disconnection.
* trackable must be inherited when objects shall automatically
* invalidate slots referring to them on destruction.
* A slot built from a member function of a trackable derived
* type installs a callback that is invoked when the trackable object
* is destroyed or overwritten.
*
* add_destroy_notify_callback() and remove_destroy_notify_callback()
* can be used to manually install and remove callbacks when
* notification of the object dying is needed.
*
* notify_callbacks() invokes and removes all previously installed
* callbacks and can therefore be used to disconnect from all signals.
*
* Note that there is no virtual destructor. Don't use @p trackable*
* as pointer type for managing your data or the destructors of
* your derived types won't be called when deleting your objects.
*
* @ingroup signal
*/
struct SIGC_API trackable
{
// Concerning noexcept specifications:
// libsigc++ does not have complete control of what happens when notify_callbacks()
// is called. It may throw an exception. A method that calls notify_callbacks()
// shall not be declared noexcept.
trackable() noexcept;
trackable(const trackable& src) noexcept;
trackable(trackable&& src);
trackable& operator=(const trackable& src);
trackable& operator=(trackable&& src);
~trackable();
/*virtual ~trackable() {} */ /* we would need a virtual dtor for users
who insist on using "trackable*" as
pointer type for their own derived objects */
typedef internal::func_destroy_notify func_destroy_notify;
/** Add a callback that is executed (notified) when the trackable object is detroyed.
* @param data Passed into func upon notification.
* @param func Callback executed upon destruction of the object.
*/
void add_destroy_notify_callback(void* data, func_destroy_notify func) const;
/** Remove a callback previously installed with add_destroy_notify_callback().
* The callback is not executed.
* @param data Parameter passed into previous call to add_destroy_notify_callback().
*/
void remove_destroy_notify_callback(void* data) const;
/// Execute and remove all previously installed callbacks.
void notify_callbacks();
#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
/* The callbacks are held in a list of type trackable_callback_list.
* This list is allocated dynamically when the first callback is added.
*/
internal::trackable_callback_list* callback_list() const;
mutable internal::trackable_callback_list* callback_list_;
#endif
};
} /* namespace sigc */
#endif /* _SIGC_TRACKABLE_HPP_ */
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