From 057ef1d83ba263fb2adf1aa86f8e281ab0065c43 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Fri, 8 Apr 2016 00:15:32 +0200
Subject: Refactoring to finally get rid of MessageHandler/Receiver in favor of
 the new Settings mechanism.

---
 src/notifier.h | 163 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 src/notifier.h

(limited to 'src/notifier.h')

diff --git a/src/notifier.h b/src/notifier.h
new file mode 100644
index 0000000..ff59741
--- /dev/null
+++ b/src/notifier.h
@@ -0,0 +1,163 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            notifier.h
+ *
+ *  Thu Sep  3 15:48:39 CEST 2015
+ *  Copyright 2015 Bent Bisballe Nyeng
+ *  deva@aasimon.org
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo 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 DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <functional>
+#include <vector>
+#include <map>
+#include <set>
+#include <memory>
+
+namespace aux
+{
+	template<int>
+	struct placeholder
+	{
+	};
+}
+
+namespace std
+{
+	template<int N>
+	struct is_placeholder<aux::placeholder<N>>
+		: integral_constant<int, N+1>
+	{
+	};
+}
+
+namespace aux
+{
+	// std::integer_sequence introduced in C++14 so remove this once we start requiring that.
+
+	template<int... Ns>
+	struct int_sequence
+	{
+	};
+
+	template<int N, int... Ns>
+	struct gen_int_sequence
+		: gen_int_sequence<N-1, N-1, Ns...>
+	{
+	};
+
+	template<int... Ns>
+	struct gen_int_sequence<0, Ns...>
+		: int_sequence<Ns...>
+	{
+	};
+};
+
+
+//namespace GUI {
+
+class Listener;
+class NotifierBase {
+public:
+	virtual void disconnect(Listener* object) {}
+};
+
+class Listener {
+public:
+	virtual ~Listener()
+	{
+		for(auto signal : signals)
+		{
+			signal->disconnect(this);
+		}
+	}
+
+	void registerNotifier(NotifierBase* signal)
+	{
+		signals.insert(signal);
+	}
+
+	void unregisterNotifier(NotifierBase* signal)
+	{
+		signals.erase(signal);
+	}
+
+private:
+	std::set<NotifierBase*> signals;
+};
+
+template<typename... Args>
+class Notifier : public NotifierBase {
+public:
+	Notifier() {}
+
+	//! \brief When dtor is called it will automatically disconnect all its listeners.
+	~Notifier()
+	{
+		for(auto& slot : slots)
+		{
+			slot.first->unregisterNotifier(this);
+		}
+	}
+
+	using callback_type = std::function<void(Args...)>;
+
+	//! \brief Connect object to this Notifier.
+	template<typename O, typename F>
+	void connect(O* p, const F& fn)
+	{
+		slots[p] = std::move(construct_mem_fn(fn, p, aux::gen_int_sequence<sizeof...(Args)>{}));
+		if(p && dynamic_cast<Listener*>(p))
+		{
+			dynamic_cast<Listener*>(p)->registerNotifier(this);
+		}
+	}
+
+	//! \brief Disconnect object from this Notifier.
+	void disconnect(Listener* object)
+	{
+		slots.erase(object);
+	}
+
+	//! \brief Activate this notifier by pretending it is a function.
+	//! Example: Notifier<int> foo; foo(42);
+	void operator()(Args... args)
+	{
+		for(auto& slot : slots)
+		{
+			slot.second(args...);
+		}
+	}
+
+private:
+	std::map<Listener*, callback_type> slots;
+
+	template<typename F, typename O, int... Ns>
+	callback_type construct_mem_fn(const F& fn, O* p, aux::int_sequence<Ns...>) const
+	{
+		return std::bind(fn, p, aux::placeholder<Ns>{}...);
+	}
+
+};
+
+//} // GUI::
+
+#define CONNECT(SRC, SIG, TAR, SLO) (SRC)->SIG.connect(TAR, SLO)
-- 
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