mirror of
https://github.com/mozilla/gecko-dev.git
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455 lines
9.5 KiB
C++
455 lines
9.5 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 nsAutoPtr_h
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#define nsAutoPtr_h
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#include "nsCOMPtr.h"
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#include "mozilla/RefPtr.h"
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#include "mozilla/TypeTraits.h"
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#include "nsCycleCollectionNoteChild.h"
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#include "mozilla/MemoryReporting.h"
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/*****************************************************************************/
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// template <class T> class nsAutoPtrGetterTransfers;
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template <class T>
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class nsAutoPtr
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{
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private:
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static_assert(!mozilla::IsScalar<T>::value, "If you are using "
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"nsAutoPtr to hold an array, use UniquePtr<T[]> instead");
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void**
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begin_assignment()
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{
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assign(0);
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return reinterpret_cast<void**>(&mRawPtr);
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}
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void
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assign(T* aNewPtr)
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{
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T* oldPtr = mRawPtr;
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if (aNewPtr && aNewPtr == oldPtr) {
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NS_RUNTIMEABORT("Logic flaw in the caller");
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}
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mRawPtr = aNewPtr;
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delete oldPtr;
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}
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// |class Ptr| helps us prevent implicit "copy construction"
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// through |operator T*() const| from a |const nsAutoPtr<T>|
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// because two implicit conversions in a row aren't allowed.
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// It still allows assignment from T* through implicit conversion
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// from |T*| to |nsAutoPtr<T>::Ptr|
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class Ptr
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{
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public:
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MOZ_IMPLICIT Ptr(T* aPtr)
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: mPtr(aPtr)
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{
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}
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operator T*() const
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{
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return mPtr;
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}
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private:
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T* MOZ_NON_OWNING_REF mPtr;
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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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~nsAutoPtr()
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{
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delete mRawPtr;
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}
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// Constructors
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nsAutoPtr()
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: mRawPtr(0)
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// default constructor
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{
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}
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MOZ_IMPLICIT nsAutoPtr(Ptr aRawPtr)
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: mRawPtr(aRawPtr)
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// construct from a raw pointer (of the right type)
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{
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}
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// This constructor shouldn't exist; we should just use the &&
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// constructor.
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nsAutoPtr(nsAutoPtr<T>& aSmartPtr)
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: mRawPtr(aSmartPtr.forget())
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// Construct by transferring ownership from another smart pointer.
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{
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}
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template <typename I>
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MOZ_IMPLICIT nsAutoPtr(nsAutoPtr<I>& aSmartPtr)
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: mRawPtr(aSmartPtr.forget())
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// Construct by transferring ownership from another smart pointer.
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{
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}
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nsAutoPtr(nsAutoPtr<T>&& aSmartPtr)
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: mRawPtr(aSmartPtr.forget())
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// Construct by transferring ownership from another smart pointer.
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{
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}
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template <typename I>
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MOZ_IMPLICIT nsAutoPtr(nsAutoPtr<I>&& aSmartPtr)
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: mRawPtr(aSmartPtr.forget())
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// Construct by transferring ownership from another smart pointer.
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{
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}
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// Assignment operators
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nsAutoPtr<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(aRhs);
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return *this;
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}
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nsAutoPtr<T>& operator=(nsAutoPtr<T>& aRhs)
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// assign by transferring ownership from another smart pointer.
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{
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assign(aRhs.forget());
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return *this;
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}
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template <typename I>
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nsAutoPtr<T>& operator=(nsAutoPtr<I>& aRhs)
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// assign by transferring ownership from another smart pointer.
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{
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assign(aRhs.forget());
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return *this;
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}
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nsAutoPtr<T>& operator=(nsAutoPtr<T>&& aRhs)
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{
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assign(aRhs.forget());
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return *this;
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}
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template <typename I>
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nsAutoPtr<T>& operator=(nsAutoPtr<I>&& aRhs)
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{
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assign(aRhs.forget());
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return *this;
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}
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// Other pointer operators
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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
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|operator T*() const|. Use |get()| _only_ to resolve
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ambiguity.
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*/
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{
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return mRawPtr;
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}
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operator T*() const
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/*
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...makes an |nsAutoPtr| act like its underlying raw pointer
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type whenever it is used in a context where a raw pointer
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is expected. It is this operator that makes an |nsAutoPtr|
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substitutable for a raw pointer.
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Prefer the implicit use of this operator to calling |get()|,
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except where 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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T*
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forget()
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{
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T* temp = mRawPtr;
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mRawPtr = 0;
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return temp;
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}
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T*
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operator->() const
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{
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NS_PRECONDITION(mRawPtr != 0,
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"You can't dereference a NULL nsAutoPtr 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 C, typename... Args>
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Proxy<R, Args...> operator->*(R (C::*aFptr)(Args...)) const
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{
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NS_PRECONDITION(mRawPtr != 0,
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"You can't dereference a NULL nsAutoPtr with operator->*().");
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return Proxy<R, Args...>(get(), aFptr);
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}
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nsAutoPtr<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 nsAutoPtr<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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NS_PRECONDITION(mRawPtr != 0,
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"You can't dereference a NULL nsAutoPtr 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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#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
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return reinterpret_cast<T**>(begin_assignment());
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#else
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assign(0);
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return reinterpret_cast<T**>(&mRawPtr);
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#endif
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}
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};
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template <class T>
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inline nsAutoPtr<T>*
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address_of(nsAutoPtr<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 nsAutoPtr<T>*
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address_of(const nsAutoPtr<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 nsAutoPtrGetterTransfers
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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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nsAutoPtr<IFoo> fooP;
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...->GetTransferedPointer(getter_Transfers(fooP))
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DO NOT USE THIS TYPE DIRECTLY IN YOUR CODE. Use |getter_Transfers()| instead.
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When initialized with a |nsAutoPtr|, 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 (|GetTransferedPointer| in this case) can fill in.
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This type should be a nested class inside |nsAutoPtr<T>|.
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*/
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{
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public:
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explicit
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nsAutoPtrGetterTransfers(nsAutoPtr<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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nsAutoPtr<T>& mTargetSmartPtr;
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};
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template <class T>
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inline nsAutoPtrGetterTransfers<T>
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getter_Transfers(nsAutoPtr<T>& aSmartPtr)
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/*
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Used around a |nsAutoPtr| when
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...makes the class |nsAutoPtrGetterTransfers<T>| invisible.
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*/
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{
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return nsAutoPtrGetterTransfers<T>(aSmartPtr);
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}
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// Comparing two |nsAutoPtr|s
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template <class T, class U>
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inline bool
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operator==(const nsAutoPtr<T>& aLhs, const nsAutoPtr<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 nsAutoPtr<T>& aLhs, const nsAutoPtr<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 |nsAutoPtr| 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 nsAutoPtr<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 nsAutoPtr<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 nsAutoPtr<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 nsAutoPtr<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 nsAutoPtr<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 nsAutoPtr<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 nsAutoPtr<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 nsAutoPtr<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 |nsAutoPtr| to |nullptr|
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template <class T>
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inline bool
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operator==(const nsAutoPtr<T>& aLhs, decltype(nullptr))
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{
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return aLhs.get() == nullptr;
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}
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template <class T>
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inline bool
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operator==(decltype(nullptr), const nsAutoPtr<T>& aRhs)
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{
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return nullptr == aRhs.get();
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}
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template <class T>
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inline bool
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operator!=(const nsAutoPtr<T>& aLhs, decltype(nullptr))
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{
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return aLhs.get() != nullptr;
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}
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template <class T>
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inline bool
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operator!=(decltype(nullptr), const nsAutoPtr<T>& aRhs)
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{
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return nullptr != aRhs.get();
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}
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/*****************************************************************************/
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#endif // !defined(nsAutoPtr_h)
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