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/*
* Copyright 2002 - 2016, 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++/functors/slot_base.h>
#include <sigc++/weak_raw_ptr.h>
namespace sigc
{
/** Convenience class for safe disconnection.
*
* This may be used to disconnect the referred slot at any time (disconnect()).
* @ref sigc::signal_with_accumulator::connect() "sigc::signal::connect()" and
* @ref sigc::signal_with_accumulator::connect_first() "sigc::signal::connect_first()"
* return a %sigc::connection.
*
* @code
* sigc::connection conn = sig.connect(sigc::mem_fun(a, &A::foo));
* @endcode
*
* 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()).
*
* sigc::connection doesnʼt disconnect the slot automatically upon destruction.
* You do not need to keep the sigc::connection object to retain the connection
* of the slot to the signal. See also @ref sigc::scoped_connection, which does
* disconnect automatically when the connection object is destroyed or replaced.
*
* @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 object.
* @param slot The slot to operate on.
*/
explicit connection(slot_base& slot);
/** Overrides this connection object copying another one.
* @param src The connection object to make a copy from.
*/
connection& operator=(const connection& src);
~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();
/** Returns whether the connection is still active.
* @return @p true if the connection is still active.
*/
explicit operator bool() const noexcept;
private:
void set_slot(const sigc::internal::weak_raw_ptr<slot_base>& sl);
/* Referred slot. Set to nullptr when the referred slot is deleted.
* A value of nullptr indicates an "empty" connection.
*/
sigc::internal::weak_raw_ptr<slot_base> slot_;
};
} /* namespace sigc */
#endif /* SIGC_CONNECTION_HPP */
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