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livetrax/libs/pbd/pbd/signals.h

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3.4 KiB
C++

/*
Copyright (C) 2009-2012 Paul Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __pbd_signals_h__
#define __pbd_signals_h__
#include <list>
#include <map>
#ifdef nil
#undef nil
#endif
#include <glibmm/threads.h>
#include <boost/noncopyable.hpp>
#include <boost/bind.hpp>
#include <boost/bind/protect.hpp>
#include <boost/function.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/optional.hpp>
#include "pbd/libpbd_visibility.h"
#include "pbd/event_loop.h"
namespace PBD {
class LIBPBD_API Connection;
class LIBPBD_API SignalBase
{
public:
virtual ~SignalBase () {}
virtual void disconnect (boost::shared_ptr<Connection>) = 0;
protected:
Glib::Threads::Mutex _mutex;
};
class LIBPBD_API Connection : public boost::enable_shared_from_this<Connection>
{
public:
Connection (SignalBase* b) : _signal (b) {}
void disconnect ()
{
Glib::Threads::Mutex::Lock lm (_mutex);
if (_signal) {
_signal->disconnect (shared_from_this ());
_signal = 0;
}
}
void signal_going_away ()
{
Glib::Threads::Mutex::Lock lm (_mutex);
_signal = 0;
}
private:
Glib::Threads::Mutex _mutex;
SignalBase* _signal;
};
template<typename R>
class /*LIBPBD_API*/ OptionalLastValue
{
public:
typedef boost::optional<R> result_type;
template <typename Iter>
result_type operator() (Iter first, Iter last) const {
result_type r;
while (first != last) {
r = *first;
++first;
}
return r;
}
};
typedef boost::shared_ptr<Connection> UnscopedConnection;
class LIBPBD_API ScopedConnection
{
public:
ScopedConnection () {}
ScopedConnection (UnscopedConnection c) : _c (c) {}
~ScopedConnection () {
disconnect ();
}
void disconnect ()
{
if (_c) {
_c->disconnect ();
}
}
ScopedConnection& operator= (UnscopedConnection const & o)
{
if (_c == o) {
return *this;
}
disconnect ();
_c = o;
return *this;
}
private:
UnscopedConnection _c;
};
class LIBPBD_API ScopedConnectionList : public boost::noncopyable
{
public:
ScopedConnectionList();
virtual ~ScopedConnectionList ();
void add_connection (const UnscopedConnection& c);
void drop_connections ();
private:
/* this class is not copyable */
ScopedConnectionList(const ScopedConnectionList&);
/* Even though our signals code is thread-safe, this additional list of
scoped connections needs to be protected in 2 cases:
(1) (unlikely) we make a connection involving a callback on the
same object from 2 threads. (wouldn't that just be appalling
programming style?)
(2) where we are dropping connections in one thread and adding
one from another.
*/
Glib::Threads::Mutex _lock;
typedef std::list<ScopedConnection*> ConnectionList;
ConnectionList _list;
};
#include "pbd/signals_generated.h"
} /* namespace */
#endif /* __pbd_signals_h__ */