56 lines
901 B
C++
56 lines
901 B
C++
/*
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* \brief Pointer that can be dereferenced only when valid
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* \author Martin Stein
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* \date 2017-03-08
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*/
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/*
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* Copyright (C) 2016-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _POINTER_H_
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#define _POINTER_H_
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/* Genode includes */
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#include <base/exception.h>
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namespace Net { template <typename> class Pointer; }
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template <typename T>
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class Net::Pointer
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{
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private:
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T *_ptr;
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public:
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struct Valid : Genode::Exception { };
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struct Invalid : Genode::Exception { };
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Pointer() : _ptr(nullptr) { }
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T &deref() const
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{
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if (_ptr == nullptr) {
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throw Invalid(); }
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return *_ptr;
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}
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void set(T &ptr)
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{
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if (_ptr != nullptr) {
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throw Valid(); }
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_ptr = &ptr;
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}
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void unset() { _ptr = nullptr; }
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};
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#endif /* _POINTER_H_ */
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