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https://github.com/libretro/scummvm.git
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ec24687ce4
Adding @defgroup and @ingroup doxygen tags into all headers in the common folder that contain doxygen blocks. This improves the structure, readability, and findability of information in the resulting output. This commit targets purely structure and does not deal with the content of the currently existing doxygen documentation.
118 lines
3.1 KiB
C++
118 lines
3.1 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
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#ifndef COMMON_SINGLETON_H
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#define COMMON_SINGLETON_H
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#include "common/noncopyable.h"
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namespace Common {
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/**
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* @defgroup common_singleton Singleton
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* @ingroup common
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*
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* @brief API for managing singletons.
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*
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* @{
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*/
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/**
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* Generic template base class for implementing the singleton design pattern.
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*/
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template<class T>
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class Singleton : NonCopyable {
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private:
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Singleton<T>(const Singleton<T> &);
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Singleton<T> &operator=(const Singleton<T> &);
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/**
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* The default object factory used by the template class Singleton.
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* By specialising this template function, one can make a singleton use a
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* custom object factory. For example, to support encapsulation, your
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* singleton class might be pure virtual (or "abstract" in Java terminology),
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* and you specialise makeInstance to return an instance of a subclass.
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*/
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//template<class T>
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#if defined(__WINS__)
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//FIXME verify if __WINS__ needs this still
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public:
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#endif
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static T *makeInstance() {
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return new T();
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}
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static void destroyInstance() {
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delete _singleton;
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_singleton = 0;
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}
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public:
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static bool hasInstance() {
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return _singleton != 0;
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}
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static T& instance() {
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// TODO: We aren't thread safe. For now we ignore it since the
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// only thing using this singleton template is the config manager,
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// and that is first instantiated long before any threads.
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// TODO: We don't leak, but the destruction order is nevertheless
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// semi-random. If we use multiple singletons, the destruction
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// order might become an issue. There are various approaches
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// to solve that problem, but for now this is sufficient
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if (!_singleton)
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_singleton = T::makeInstance();
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return *_singleton;
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}
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static void destroy() {
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T::destroyInstance();
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}
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protected:
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Singleton<T>() { }
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#ifdef __SYMBIAN32__
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virtual ~Singleton() { }
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#else
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virtual ~Singleton<T>() { }
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#endif
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typedef T SingletonBaseType;
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static T *_singleton;
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};
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/**
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* Note that you need to use this macro from the Common namespace.
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*
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* This is because C++ requires initial explicit specialization
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* to be placed in the same namespace as the template.
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*/
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#define DECLARE_SINGLETON(T) \
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template<> T *Singleton<T>::_singleton = 0
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/** @} */
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} // End of namespace Common
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#endif
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