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50eb249b57
A number of places depend on RefPtr.h providing this function. When we s/RefPtr/nsRefPtr/, such places still need to be able to see this function. Moving it to nsRefPtr.h makes it still visible before we switch (since RefPtr.h includes nsRefPtr.h), and after we switch (since every place that #includes RefPtr.h will now be #including nsRefPtr.h).
616 lines
14 KiB
C++
616 lines
14 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_nsRefPtr_h
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#define mozilla_nsRefPtr_h
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#include "mozilla/AlreadyAddRefed.h"
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#include "mozilla/Assertions.h"
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#include "mozilla/Attributes.h"
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/*****************************************************************************/
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// template <class T> class nsRefPtrGetterAddRefs;
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class nsCOMPtr_helper;
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namespace mozilla {
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template<class T> class OwningNonNull;
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template<class T> class RefPtr;
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} // namespace mozilla
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template <class T>
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class nsRefPtr
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{
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private:
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void
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assign_with_AddRef(T* aRawPtr)
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{
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if (aRawPtr) {
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AddRefTraits<T>::AddRef(aRawPtr);
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}
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assign_assuming_AddRef(aRawPtr);
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}
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void
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assign_assuming_AddRef(T* aNewPtr)
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{
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T* oldPtr = mRawPtr;
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mRawPtr = aNewPtr;
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if (oldPtr) {
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AddRefTraits<T>::Release(oldPtr);
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}
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}
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private:
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T* MOZ_OWNING_REF mRawPtr;
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public:
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typedef T element_type;
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~nsRefPtr()
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{
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if (mRawPtr) {
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AddRefTraits<T>::Release(mRawPtr);
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}
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}
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// Constructors
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nsRefPtr()
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: mRawPtr(0)
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// default constructor
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{
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}
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nsRefPtr(const nsRefPtr<T>& aSmartPtr)
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: mRawPtr(aSmartPtr.mRawPtr)
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// copy-constructor
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{
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if (mRawPtr) {
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AddRefTraits<T>::AddRef(mRawPtr);
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}
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}
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nsRefPtr(nsRefPtr<T>&& aRefPtr)
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: mRawPtr(aRefPtr.mRawPtr)
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{
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aRefPtr.mRawPtr = nullptr;
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}
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// construct from a raw pointer (of the right type)
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MOZ_IMPLICIT nsRefPtr(T* aRawPtr)
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: mRawPtr(aRawPtr)
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{
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if (mRawPtr) {
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AddRefTraits<T>::AddRef(mRawPtr);
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}
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}
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template <typename I>
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MOZ_IMPLICIT nsRefPtr(already_AddRefed<I>& aSmartPtr)
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: mRawPtr(aSmartPtr.take())
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// construct from |already_AddRefed|
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{
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}
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template <typename I>
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MOZ_IMPLICIT nsRefPtr(already_AddRefed<I>&& aSmartPtr)
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: mRawPtr(aSmartPtr.take())
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// construct from |otherRefPtr.forget()|
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{
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}
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template <typename I>
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MOZ_IMPLICIT nsRefPtr(const nsRefPtr<I>& aSmartPtr)
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: mRawPtr(aSmartPtr.get())
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// copy-construct from a smart pointer with a related pointer type
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{
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if (mRawPtr) {
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AddRefTraits<T>::AddRef(mRawPtr);
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}
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}
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template <typename I>
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MOZ_IMPLICIT nsRefPtr(nsRefPtr<I>&& aSmartPtr)
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: mRawPtr(aSmartPtr.forget().take())
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// construct from |Move(nsRefPtr<SomeSubclassOfT>)|.
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{
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}
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MOZ_IMPLICIT nsRefPtr(const nsCOMPtr_helper& aHelper);
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// Defined in OwningNonNull.h
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template<class U>
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MOZ_IMPLICIT nsRefPtr(const mozilla::OwningNonNull<U>& aOther);
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// Defined in RefPtr.h
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template<class U>
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MOZ_IMPLICIT nsRefPtr(mozilla::RefPtr<U>&& aOther);
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// Assignment operators
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nsRefPtr<T>&
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operator=(const nsRefPtr<T>& aRhs)
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// copy assignment operator
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{
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assign_with_AddRef(aRhs.mRawPtr);
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return *this;
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}
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template <typename I>
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nsRefPtr<T>&
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operator=(const nsRefPtr<I>& aRhs)
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// assign from an nsRefPtr of a related pointer type
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{
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assign_with_AddRef(aRhs.get());
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return *this;
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}
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nsRefPtr<T>&
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operator=(T* aRhs)
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// assign from a raw pointer (of the right type)
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{
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assign_with_AddRef(aRhs);
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return *this;
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}
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template <typename I>
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nsRefPtr<T>&
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operator=(already_AddRefed<I>& aRhs)
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// assign from |already_AddRefed|
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{
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assign_assuming_AddRef(aRhs.take());
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return *this;
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}
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template <typename I>
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nsRefPtr<T>&
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operator=(already_AddRefed<I> && aRhs)
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// assign from |otherRefPtr.forget()|
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{
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assign_assuming_AddRef(aRhs.take());
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return *this;
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}
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nsRefPtr<T>& operator=(const nsCOMPtr_helper& aHelper);
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nsRefPtr<T>&
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operator=(nsRefPtr<T> && aRefPtr)
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{
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assign_assuming_AddRef(aRefPtr.mRawPtr);
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aRefPtr.mRawPtr = nullptr;
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return *this;
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}
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// Defined in OwningNonNull.h
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template<class U>
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nsRefPtr<T>&
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operator=(const mozilla::OwningNonNull<U>& aOther);
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// Defined in RefPtr.h
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template<class U>
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nsRefPtr<T>&
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operator=(mozilla::RefPtr<U>&& aOther);
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// Other pointer operators
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void
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swap(nsRefPtr<T>& aRhs)
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// ...exchange ownership with |aRhs|; can save a pair of refcount operations
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{
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T* temp = aRhs.mRawPtr;
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aRhs.mRawPtr = mRawPtr;
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mRawPtr = temp;
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}
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void
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swap(T*& aRhs)
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// ...exchange ownership with |aRhs|; can save a pair of refcount operations
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{
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T* temp = aRhs;
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aRhs = mRawPtr;
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mRawPtr = temp;
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}
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already_AddRefed<T>
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forget()
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// return the value of mRawPtr and null out mRawPtr. Useful for
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// already_AddRefed return values.
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{
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T* temp = 0;
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swap(temp);
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return already_AddRefed<T>(temp);
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}
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template <typename I>
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void
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forget(I** aRhs)
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// Set the target of aRhs to the value of mRawPtr and null out mRawPtr.
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// Useful to avoid unnecessary AddRef/Release pairs with "out"
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// parameters where aRhs bay be a T** or an I** where I is a base class
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// of T.
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{
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MOZ_ASSERT(aRhs, "Null pointer passed to forget!");
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*aRhs = mRawPtr;
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mRawPtr = 0;
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}
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T*
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get() const
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/*
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Prefer the implicit conversion provided automatically by |operator T*() const|.
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Use |get()| to resolve ambiguity or to get a castable pointer.
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*/
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{
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return const_cast<T*>(mRawPtr);
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}
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operator T*() const
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#ifdef MOZ_HAVE_REF_QUALIFIERS
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&
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#endif
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/*
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...makes an |nsRefPtr| act like its underlying raw pointer type whenever it
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is used in a context where a raw pointer is expected. It is this operator
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that makes an |nsRefPtr| substitutable for a raw pointer.
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Prefer the implicit use of this operator to calling |get()|, except where
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necessary to resolve ambiguity.
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*/
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{
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return get();
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}
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#ifdef MOZ_HAVE_REF_QUALIFIERS
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// Don't allow implicit conversion of temporary nsRefPtr to raw pointer,
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// because the refcount might be one and the pointer will immediately become
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// invalid.
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operator T*() const && = delete;
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// These are needed to avoid the deleted operator above. XXX Why is operator!
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// needed separately? Shouldn't the compiler prefer using the non-deleted
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// operator bool instead of the deleted operator T*?
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explicit operator bool() const { return !!mRawPtr; }
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bool operator!() const { return !mRawPtr; }
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#endif
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T*
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operator->() const MOZ_NO_ADDREF_RELEASE_ON_RETURN
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{
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MOZ_ASSERT(mRawPtr != 0,
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"You can't dereference a NULL nsRefPtr with operator->().");
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return get();
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}
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template <typename R, typename... Args>
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class Proxy
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{
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typedef R (T::*member_function)(Args...);
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T* mRawPtr;
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member_function mFunction;
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public:
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Proxy(T* aRawPtr, member_function aFunction)
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: mRawPtr(aRawPtr),
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mFunction(aFunction)
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{
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}
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template<typename... ActualArgs>
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R operator()(ActualArgs&&... aArgs)
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{
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return ((*mRawPtr).*mFunction)(mozilla::Forward<ActualArgs>(aArgs)...);
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}
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};
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template <typename R, typename... Args>
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Proxy<R, Args...> operator->*(R (T::*aFptr)(Args...)) const
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{
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MOZ_ASSERT(mRawPtr != 0,
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"You can't dereference a NULL nsRefPtr with operator->*().");
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return Proxy<R, Args...>(get(), aFptr);
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}
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nsRefPtr<T>*
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get_address()
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// This is not intended to be used by clients. See |address_of|
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// below.
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{
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return this;
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}
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const nsRefPtr<T>*
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get_address() const
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// This is not intended to be used by clients. See |address_of|
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// below.
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{
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return this;
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}
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public:
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T&
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operator*() const
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{
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MOZ_ASSERT(mRawPtr != 0,
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"You can't dereference a NULL nsRefPtr with operator*().");
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return *get();
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}
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T**
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StartAssignment()
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{
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assign_assuming_AddRef(0);
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return reinterpret_cast<T**>(&mRawPtr);
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}
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private:
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// This helper class makes |nsRefPtr<const T>| possible by casting away
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// the constness from the pointer when calling AddRef() and Release().
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//
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// This is necessary because AddRef() and Release() implementations can't
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// generally expected to be const themselves (without heavy use of |mutable|
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// and |const_cast| in their own implementations).
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//
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// This should be sound because while |nsRefPtr<const T>| provides a
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// const view of an object, the object itself should not be const (it
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// would have to be allocated as |new const T| or similar to be const).
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template<class U>
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struct AddRefTraits
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{
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static void AddRef(U* aPtr) {
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aPtr->AddRef();
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}
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static void Release(U* aPtr) {
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aPtr->Release();
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}
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};
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template<class U>
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struct AddRefTraits<const U>
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{
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static void AddRef(const U* aPtr) {
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const_cast<U*>(aPtr)->AddRef();
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}
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static void Release(const U* aPtr) {
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const_cast<U*>(aPtr)->Release();
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}
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};
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};
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class nsCycleCollectionTraversalCallback;
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template <typename T>
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void
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CycleCollectionNoteChild(nsCycleCollectionTraversalCallback& aCallback,
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T* aChild, const char* aName, uint32_t aFlags);
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template <typename T>
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inline void
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ImplCycleCollectionUnlink(nsRefPtr<T>& aField)
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{
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aField = nullptr;
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}
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template <typename T>
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inline void
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ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
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nsRefPtr<T>& aField,
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const char* aName,
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uint32_t aFlags = 0)
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{
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CycleCollectionNoteChild(aCallback, aField.get(), aName, aFlags);
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}
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template <class T>
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inline nsRefPtr<T>*
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address_of(nsRefPtr<T>& aPtr)
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{
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return aPtr.get_address();
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}
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template <class T>
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inline const nsRefPtr<T>*
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address_of(const nsRefPtr<T>& aPtr)
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{
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return aPtr.get_address();
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}
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template <class T>
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class nsRefPtrGetterAddRefs
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/*
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...
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This class is designed to be used for anonymous temporary objects in the
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argument list of calls that return COM interface pointers, e.g.,
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nsRefPtr<IFoo> fooP;
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...->GetAddRefedPointer(getter_AddRefs(fooP))
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DO NOT USE THIS TYPE DIRECTLY IN YOUR CODE. Use |getter_AddRefs()| instead.
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When initialized with a |nsRefPtr|, as in the example above, it returns
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a |void**|, a |T**|, or an |nsISupports**| as needed, that the
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outer call (|GetAddRefedPointer| in this case) can fill in.
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This type should be a nested class inside |nsRefPtr<T>|.
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*/
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{
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public:
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explicit
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nsRefPtrGetterAddRefs(nsRefPtr<T>& aSmartPtr)
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: mTargetSmartPtr(aSmartPtr)
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{
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// nothing else to do
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}
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operator void**()
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{
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return reinterpret_cast<void**>(mTargetSmartPtr.StartAssignment());
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}
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operator T**()
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{
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return mTargetSmartPtr.StartAssignment();
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}
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T*&
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operator*()
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{
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return *(mTargetSmartPtr.StartAssignment());
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}
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private:
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nsRefPtr<T>& mTargetSmartPtr;
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};
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template <class T>
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inline nsRefPtrGetterAddRefs<T>
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getter_AddRefs(nsRefPtr<T>& aSmartPtr)
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/*
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Used around a |nsRefPtr| when
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...makes the class |nsRefPtrGetterAddRefs<T>| invisible.
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*/
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{
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return nsRefPtrGetterAddRefs<T>(aSmartPtr);
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}
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// Comparing two |nsRefPtr|s
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template <class T, class U>
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inline bool
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operator==(const nsRefPtr<T>& aLhs, const nsRefPtr<U>& aRhs)
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{
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return static_cast<const T*>(aLhs.get()) == static_cast<const U*>(aRhs.get());
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}
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template <class T, class U>
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inline bool
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operator!=(const nsRefPtr<T>& aLhs, const nsRefPtr<U>& aRhs)
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{
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return static_cast<const T*>(aLhs.get()) != static_cast<const U*>(aRhs.get());
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}
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// Comparing an |nsRefPtr| to a raw pointer
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template <class T, class U>
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inline bool
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operator==(const nsRefPtr<T>& aLhs, const U* aRhs)
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{
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return static_cast<const T*>(aLhs.get()) == static_cast<const U*>(aRhs);
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}
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template <class T, class U>
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inline bool
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operator==(const U* aLhs, const nsRefPtr<T>& aRhs)
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{
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return static_cast<const U*>(aLhs) == static_cast<const T*>(aRhs.get());
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}
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template <class T, class U>
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inline bool
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operator!=(const nsRefPtr<T>& aLhs, const U* aRhs)
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{
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return static_cast<const T*>(aLhs.get()) != static_cast<const U*>(aRhs);
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}
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template <class T, class U>
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inline bool
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operator!=(const U* aLhs, const nsRefPtr<T>& aRhs)
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{
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return static_cast<const U*>(aLhs) != static_cast<const T*>(aRhs.get());
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}
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template <class T, class U>
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inline bool
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operator==(const nsRefPtr<T>& aLhs, U* aRhs)
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{
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return static_cast<const T*>(aLhs.get()) == const_cast<const U*>(aRhs);
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}
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template <class T, class U>
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inline bool
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operator==(U* aLhs, const nsRefPtr<T>& aRhs)
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{
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return const_cast<const U*>(aLhs) == static_cast<const T*>(aRhs.get());
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}
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template <class T, class U>
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inline bool
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operator!=(const nsRefPtr<T>& aLhs, U* aRhs)
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{
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return static_cast<const T*>(aLhs.get()) != const_cast<const U*>(aRhs);
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}
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template <class T, class U>
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inline bool
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operator!=(U* aLhs, const nsRefPtr<T>& aRhs)
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{
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return const_cast<const U*>(aLhs) != static_cast<const T*>(aRhs.get());
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}
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// Comparing an |nsRefPtr| to |nullptr|
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template <class T>
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inline bool
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operator==(const nsRefPtr<T>& aLhs, decltype(nullptr))
|
|
{
|
|
return aLhs.get() == nullptr;
|
|
}
|
|
|
|
template <class T>
|
|
inline bool
|
|
operator==(decltype(nullptr), const nsRefPtr<T>& aRhs)
|
|
{
|
|
return nullptr == aRhs.get();
|
|
}
|
|
|
|
template <class T>
|
|
inline bool
|
|
operator!=(const nsRefPtr<T>& aLhs, decltype(nullptr))
|
|
{
|
|
return aLhs.get() != nullptr;
|
|
}
|
|
|
|
template <class T>
|
|
inline bool
|
|
operator!=(decltype(nullptr), const nsRefPtr<T>& aRhs)
|
|
{
|
|
return nullptr != aRhs.get();
|
|
}
|
|
|
|
/*****************************************************************************/
|
|
|
|
template <class T>
|
|
inline already_AddRefed<T>
|
|
do_AddRef(T*&& aObj)
|
|
{
|
|
nsRefPtr<T> ref(aObj);
|
|
return ref.forget();
|
|
}
|
|
|
|
namespace mozilla {
|
|
|
|
/**
|
|
* Helper function to be able to conveniently write things like:
|
|
*
|
|
* already_AddRefed<T>
|
|
* f(...)
|
|
* {
|
|
* return MakeAndAddRef<T>(...);
|
|
* }
|
|
*/
|
|
template<typename T, typename... Args>
|
|
already_AddRefed<T>
|
|
MakeAndAddRef(Args&&... aArgs)
|
|
{
|
|
nsRefPtr<T> p(new T(Forward<Args>(aArgs)...));
|
|
return p.forget();
|
|
}
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif /* mozilla_nsRefPtr_h */
|