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/*
* Copyright (C) 2013-2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <objc/runtime.h>
#include <type_traits>
#include <wtf/RetainPtr.h>
#include <wtf/spi/cocoa/objcSPI.h>
// Because ARC enablement is a compile-time choice, and we compile this header
// both ways, we need a separate copy of our code when ARC is enabled.
#if __has_feature(objc_arc)
#define WeakObjCPtr WeakObjCPtrArc
#endif
namespace WTF {
template<typename T> class WeakObjCPtr {
public:
using ValueType = typename std::remove_pointer<T>::type;
WeakObjCPtr() = default;
WeakObjCPtr(ValueType *ptr)
#if __has_feature(objc_arc)
: m_weakReference(ptr)
#endif
{
#if !__has_feature(objc_arc)
objc_initWeak(&m_weakReference, ptr);
#endif
}
#if !__has_feature(objc_arc)
WeakObjCPtr(const WeakObjCPtr& other)
{
objc_copyWeak(&m_weakReference, &other.m_weakReference);
}
WeakObjCPtr(WeakObjCPtr&& other)
{
objc_moveWeak(&m_weakReference, &other.m_weakReference);
}
~WeakObjCPtr()
{
objc_destroyWeak(&m_weakReference);
}
#endif
WeakObjCPtr& operator=(ValueType *ptr)
{
#if __has_feature(objc_arc)
m_weakReference = ptr;
#else
objc_storeWeak(&m_weakReference, (id)ptr);
#endif
return *this;
}
bool operator!() const { return !get(); }
explicit operator bool() const { return !!get(); }
RetainPtr<ValueType> get() const;
ValueType *getAutoreleased() const
{
#if __has_feature(objc_arc)
return static_cast<ValueType *>(m_weakReference);
#else
return static_cast<ValueType *>(objc_loadWeak(&m_weakReference));
#endif
}
explicit operator ValueType *() const { return getAutoreleased(); }
private:
#if __has_feature(objc_arc)
mutable __weak id m_weakReference { nullptr };
#else
mutable id m_weakReference { nullptr };
#endif
};
template<typename T> WeakObjCPtr(T) -> WeakObjCPtr<std::remove_pointer_t<T>>;
#ifdef __OBJC__
template<typename T>
RetainPtr<typename WeakObjCPtr<T>::ValueType> WeakObjCPtr<T>::get() const
{
#if __has_feature(objc_arc)
return static_cast<typename WeakObjCPtr<T>::ValueType *>(m_weakReference);
#else
return adoptNS(objc_loadWeakRetained(&m_weakReference));
#endif
}
#endif
} // namespace WTF
using WTF::WeakObjCPtr;
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