117 lines
2.8 KiB
C++
117 lines
2.8 KiB
C++
/* Copyright (C) 2009 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef INCLUDED_OBSERVABLE
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#define INCLUDED_OBSERVABLE
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/*
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Wrapper around Boost.Signals to make watching objects for changes more convenient.
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General usage:
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Observable<int> variable_to_be_watched;
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...
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class Thing {
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ObservableScopedConnection m_Conn;
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Thing() {
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m_Conn = variable_to_be_watched.RegisterObserver(OnChange);
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}
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void OnChange(const int& var) {
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do_something_with(var);
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}
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}
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...
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variable_to_be_watched.NotifyObservers();
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*/
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#include <boost/signals.hpp>
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#include <boost/bind.hpp>
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typedef boost::signals::connection ObservableConnection;
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typedef boost::signals::scoped_connection ObservableScopedConnection;
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template <typename T> class Observable : public T
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{
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public:
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Observable() {}
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template <typename T1>
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explicit Observable(const T1& a1) : T(a1) {}
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template <typename T1, typename T2>
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explicit Observable(T1& a1, T2 a2) : T(a1, a2) {}
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template<typename C> ObservableConnection RegisterObserver(int order, void (C::*callback) (const T&), C* obj)
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{
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return m_Signal.connect(order, boost::bind(std::mem_fun(callback), obj, _1));
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}
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ObservableConnection RegisterObserver(int order, void (*callback) (const T&))
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{
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return m_Signal.connect(order, callback);
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}
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void RemoveObserver(const ObservableConnection& conn)
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{
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conn.disconnect();
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}
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void NotifyObservers()
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{
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m_Signal(*this);
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}
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// Use when an object is changing something that it's also observing,
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// because it already knows about the change and doesn't need to be notified
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// again (particularly since that may cause infinite loops).
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void NotifyObserversExcept(ObservableConnection& conn)
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{
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if (conn.blocked())
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{
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// conn is already blocked and won't see anything
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NotifyObservers();
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}
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else
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{
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// Temporarily disable conn
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conn.block();
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NotifyObservers();
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conn.unblock();
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}
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}
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Observable<T>* operator=(const T& rhs)
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{
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*dynamic_cast<T*>(this) = rhs;
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return this;
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}
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private:
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boost::signal<void (const T&)> m_Signal;
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};
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class ObservableScopedConnections
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{
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public:
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void Add(const ObservableConnection& conn);
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~ObservableScopedConnections();
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private:
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std::vector<ObservableConnection> m_Conns;
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};
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#endif // INCLUDED_OBSERVABLE
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