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Diffstat (limited to 'kdecore/kstaticdeleter.h')
| -rw-r--r-- | kdecore/kstaticdeleter.h | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/kdecore/kstaticdeleter.h b/kdecore/kstaticdeleter.h new file mode 100644 index 000000000..ee3e5755c --- /dev/null +++ b/kdecore/kstaticdeleter.h @@ -0,0 +1,139 @@ +/* + * This file is part of the KDE Libraries + * Copyright (C) 2000 Stephan Kulow <coolo@kde.org> + * 2001 KDE Team + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public License + * along with this library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301, USA. + * + */ + +#ifndef _KSTATIC_DELETER_H_ +#define _KSTATIC_DELETER_H_ + +#include <kglobal.h> + +/** + * Static deleters are used to manage static resources. They can register + * themselves with KGlobal. KGlobal will call destructObject() when + * KGlobal::deleteStaticDeleters() is called or when it the process + * finishes. + * + * @see KStaticDeleter + * @see KGlobal::registerStaticDeleter() + * @see KGlobal::unregisterStaticDeleter() + * @see KGlobal::deleteStaticDeleters() + */ +class KDECORE_EXPORT KStaticDeleterBase { +public: + virtual ~KStaticDeleterBase() { } + /** + * Should destruct the resources managed by this KStaticDeleterBase. + * Usually you also want to call it in your destructor. + * @see KGlobal::deleteStaticDeleters() + */ + virtual void destructObject(); +}; + +/** + * Little helper class to clean up static objects that are + * held as pointer. + * When the library is unloaded, or the app terminated, all static deleters + * are destroyed, which in turn destroys those static objects properly. + * There are some rules which you should accept in the KStaticDeleter managed + * class: + * @li Don't rely on the global reference variable in the destructor of the + * object, it will be '0' at destruction time. + * @li Don't rely on other KStaticDeleter managed objects in the destructor + * of the object, because it may be destroyed before your destructor get called. + * This one can be tricky, because you might not know that you actually use a + * KStaticDeleter managed class. So try to keep your destructor simple. + * + * A typical use is + * \code + * static KStaticDeleter<MyClass> sd; + * + * MyClass &MyClass::self() { + * if (!_self) { sd.setObject(_self, new MyClass()); } + * return *_self; + * } + * \endcode + */ +template<class type> class KStaticDeleter : public KStaticDeleterBase { +public: + KStaticDeleter() { deleteit = 0; globalReference = 0; array = false; } + /** + * Sets the object to delete and registers the object to be + * deleted to KGlobal. If the given object is 0, the former + * registration is unregistered. + * @param obj the object to delete + * @param isArray tells the destructor to delete an array instead of an object + * @deprecated See the other setObject variant. + **/ + KDE_DEPRECATED type *setObject( type *obj, bool isArray = false) { + deleteit = obj; + globalReference = 0; + array = isArray; + if (obj) + KGlobal::registerStaticDeleter(this); + else + KGlobal::unregisterStaticDeleter(this); + return obj; + } + /** + * Sets the object to delete and registers the object to be + * deleted to KGlobal. If the given object is 0, the former + * registration is unregistered. + * @param globalRef the static pointer where this object is stored + * This pointer will be reset to 0 after deletion of the object. + * @param obj the object to delete + * @param isArray tells the destructor to delete an array instead of an object + **/ + type *setObject( type* & globalRef, type *obj, bool isArray = false) { + globalReference = &globalRef; + deleteit = obj; + array = isArray; + if (obj) + KGlobal::registerStaticDeleter(this); + else + KGlobal::unregisterStaticDeleter(this); + globalRef = obj; + return obj; + } + + /** + * Destructs the object. This has the same effect as deleting + * the KStaticDeleter. + */ + virtual void destructObject() { + if (globalReference) + *globalReference = 0; + if (array) + delete [] deleteit; + else + delete deleteit; + deleteit = 0; + } + virtual ~KStaticDeleter() { + KGlobal::unregisterStaticDeleter(this); + destructObject(); + } +private: + type *deleteit; + type **globalReference; + bool array; +}; + +#endif |