66 lines
2.5 KiB
C
66 lines
2.5 KiB
C
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/*
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* Copyright (C) 2017 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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namespace WTF {
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// A UnsafePointer<> can be used to hold a pointer whose lifetime is not guaranteed
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// and where the dereferencing of that pointer is therefore unsafe. Once assigned
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// to an UnsafePoniter<>, the pointer itself cannot be extracted from the class, but
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// the class can still be used to test for pointer equality.
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template<typename T>
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class UnsafePointer {
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public:
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typedef typename std::remove_pointer<T>::type ValueType;
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typedef ValueType* PtrType;
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UnsafePointer() : m_pointer(nullptr) { }
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UnsafePointer(PtrType pointer) : m_pointer(pointer) { }
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bool operator==(PtrType pointer) const { return pointer == m_pointer; }
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bool operator!=(PtrType pointer) const { return pointer != m_pointer; }
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operator bool() const { return m_pointer; }
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private:
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PtrType m_pointer;
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};
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template<typename T>
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bool operator==(typename UnsafePointer<T>::PtrType barePointer, const UnsafePointer<T>& unsafePointer)
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{
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return unsafePointer == barePointer;
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}
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template<typename T>
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bool operator!=(typename UnsafePointer<T>::PtrType barePointer, const UnsafePointer<T>& unsafePointer)
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{
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return unsafePointer != barePointer;
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}
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} // namespace WTF
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using WTF::UnsafePointer;
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