127 lines
3.4 KiB
C++
127 lines
3.4 KiB
C++
/*
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* Copyright (C) 2013-2020 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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#include <objc/runtime.h>
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#include <type_traits>
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#include <wtf/RetainPtr.h>
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#include <wtf/spi/cocoa/objcSPI.h>
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// Because ARC enablement is a compile-time choice, and we compile this header
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// both ways, we need a separate copy of our code when ARC is enabled.
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#if __has_feature(objc_arc)
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#define WeakObjCPtr WeakObjCPtrArc
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#endif
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namespace WTF {
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template<typename T> class WeakObjCPtr {
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public:
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using ValueType = typename std::remove_pointer<T>::type;
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WeakObjCPtr() = default;
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WeakObjCPtr(ValueType *ptr)
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#if __has_feature(objc_arc)
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: m_weakReference(ptr)
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#endif
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{
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#if !__has_feature(objc_arc)
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objc_initWeak(&m_weakReference, ptr);
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#endif
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}
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#if !__has_feature(objc_arc)
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WeakObjCPtr(const WeakObjCPtr& other)
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{
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objc_copyWeak(&m_weakReference, &other.m_weakReference);
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}
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WeakObjCPtr(WeakObjCPtr&& other)
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{
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objc_moveWeak(&m_weakReference, &other.m_weakReference);
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}
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~WeakObjCPtr()
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{
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objc_destroyWeak(&m_weakReference);
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}
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#endif
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WeakObjCPtr& operator=(ValueType *ptr)
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{
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#if __has_feature(objc_arc)
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m_weakReference = ptr;
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#else
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objc_storeWeak(&m_weakReference, ptr);
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#endif
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return *this;
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}
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bool operator!() const
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{
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return !get();
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}
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RetainPtr<ValueType> get() const;
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ValueType *getAutoreleased() const
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{
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#if __has_feature(objc_arc)
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return static_cast<ValueType *>(m_weakReference);
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#else
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return static_cast<ValueType *>(objc_loadWeak(&m_weakReference));
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#endif
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}
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explicit operator ValueType *() const { return getAutoreleased(); }
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private:
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#if __has_feature(objc_arc)
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mutable __weak id m_weakReference { nullptr };
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#else
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mutable id m_weakReference { nullptr };
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#endif
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};
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#ifdef __OBJC__
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template<typename T>
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RetainPtr<typename WeakObjCPtr<T>::ValueType> WeakObjCPtr<T>::get() const
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{
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#if __has_feature(objc_arc)
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return static_cast<typename WeakObjCPtr<T>::ValueType *>(m_weakReference);
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#else
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return adoptNS(objc_loadWeakRetained(&m_weakReference));
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#endif
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}
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#endif
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} // namespace WTF
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using WTF::WeakObjCPtr;
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