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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_CONNECTION_HPP_
#define _SIGC_CONNECTION_HPP_
#include <sigc++config.h>
#include <sigc++/signal.h>
namespace sigc {
/** Convinience class for safe disconnection.
* Iterators must not be used beyond the lifetime of the list
* they work on. A connection object can be created from a
* slot list iterator and may safely be used to disconnect
* the referred slot at any time (disconnect()). If the slot
* has already been destroyed, disconnect() does nothing. empty() or
* operator bool() can be used to test whether the connection is
* still active. The connection can be blocked (block(), unblock()).
*
* This is possible because the connection object gets notified
* when the referred slot dies (notify()).
*
* @ingroup signal
*/
struct SIGC_API connection
{
/** Constructs an empty connection object. */
connection() noexcept;
/** Constructs a connection object copying an existing one.
* @param c The connection object to make a copy from.
*/
connection(const connection& c);
/** Constructs a connection object from a slot list iterator.
* @param it The slot list iterator to take the slot from.
*/
template <typename T_slot>
connection(const slot_iterator<T_slot>& it) : slot_(&(*it))
{ if (slot_) slot_->add_destroy_notify_callback(this, ¬ify); }
/** Constructs a connection object from a slot object.
* This is only useful if you create your own slot list.
* @param sl The slot to operate on.
*/
explicit connection(slot_base& sl);
/** Overrides this connection object copying another one.
* @param c The connection object to make a copy from.
*/
connection& operator=(const connection& c);
/** Overrides this connection object with another slot list iterator.
* @param it The new slot list iterator to take the slot from.
*/
template <typename T_slot>
connection& operator=(const slot_iterator<T_slot>& it)
{ set_slot(&(*it)); return *this; }
~connection();
/** Returns whether the connection is still active.
* @return @p false if the connection is still active.
*/
bool empty() const noexcept;
/** Returns whether the connection is still active.
* @return @p true if the connection is still active.
*/
bool connected() const noexcept;
/** Returns whether the connection is blocked.
* @return @p true if the connection is blocked.
*/
bool blocked() const noexcept;
/** Sets or unsets the blocking state of this connection.
* See slot_base::block() for details.
* @param should_block Indicates whether the blocking state should be set or unset.
* @return @p true if the connection has been in blocking state before.
*/
bool block(bool should_block = true) noexcept;
/** Unsets the blocking state of this connection.
* @return @p true if the connection has been in blocking state before.
*/
bool unblock() noexcept;
/// Disconnects the referred slot.
void disconnect();
//TODO: When we can break API and ABI, make operator bool() const
/** Returns whether the connection is still active.
* @return @p true if the connection is still active.
*/
explicit operator bool() noexcept;
/** Callback that is executed when the referred slot is destroyed.
* @param data The connection object notified (@p this).
*/
static void* notify(void* data);
private:
void set_slot(slot_base* sl);
/* Referred slot. Set to zero from notify().
* A value of zero indicates an "empty" connection.
*/
slot_base* slot_;
};
} /* namespace sigc */
#endif /* _SIGC_TRACKABLE_HPP_ */
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