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109 lines
3 KiB
C++
109 lines
3 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program 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 3 of the License, or
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* (at your option) any later version.
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*
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* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef ULTIMA4_CORE_OBSERVABLE_H
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#define ULTIMA4_CORE_OBSERVABLE_H
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#include "ultima/ultima4/core/observer.h"
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#include "ultima/shared/std/containers.h"
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namespace Ultima {
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namespace Ultima4 {
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/**
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* Classes can report updates to a list of decoupled Observers by
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* extending this class.
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*
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* The O class parameter should be a pointer to the class of the
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* observable itself, so it can be passed in a typesafe manner to the
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* observers update method.
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*
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* The A class can be any additional information to pass to observers.
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* Observables that don't need to pass an argument when they update
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* observers should use the default "NoArg" class for the second
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* template parameter and pass nullptr to notifyObservers.
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*/
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template <class O, class A = NoArg *>
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class Observable {
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public:
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Observable() : _changed(false) {}
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void addObserver(Observer<O, A> *o) {
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typename Std::vector< Observer<O, A> *>::iterator i;
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i = Common::find(_observers.begin(), _observers.end(), o);
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if (i == _observers.end())
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_observers.push_back(o);
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}
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int countObservers() const {
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return _observers.size();
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}
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void deleteObserver(Observer<O, A> *o) {
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typename Std::vector< Observer<O, A> *>::iterator i;
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i = Common::find(_observers.begin(), _observers.end(), o);
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if (i != _observers.end())
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_observers.erase(i);
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}
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void deleteObservers() {
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_observers.clear();
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}
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bool hasChanged() const {
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return _changed;
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}
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void notifyObservers(A arg) {
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if (!_changed)
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return;
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// vector iterators are invalidated if erase is called, so a copy
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// is used to prevent problems if the observer removes itself (or
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// otherwise changes the observer list)
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typename Std::vector< Observer<O, A> *> tmp = _observers;
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typename Std::vector< Observer<O, A> *>::iterator i;
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clearChanged();
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for (i = tmp.begin(); i != tmp.end(); i++) {
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Observer<O, A> *observer = *i;
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observer->update(static_cast<O>(this), arg);
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}
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}
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protected:
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void clearChanged() {
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_changed = false;
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}
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void setChanged() {
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_changed = true;
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}
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private:
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bool _changed;
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Std::vector< Observer<O, A> *> _observers;
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};
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} // End of namespace Ultima4
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} // End of namespace Ultima
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#endif
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