mirror of
https://github.com/mozilla/gecko-dev.git
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554 lines
12 KiB
C++
554 lines
12 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 nsRefPtr_h
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#define nsRefPtr_h
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#include "mozilla/AlreadyAddRefed.h"
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#include "mozilla/Attributes.h"
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#include "nsDebug.h"
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#include "nsISupportsUtils.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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namespace dom {
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template<class T> class OwningNonNull;
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} // namespace dom
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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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aRawPtr->AddRef();
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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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begin_assignment()
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{
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assign_assuming_AddRef(0);
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return reinterpret_cast<void**>(&mRawPtr);
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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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oldPtr->Release();
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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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mRawPtr->Release();
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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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mRawPtr->AddRef();
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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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mRawPtr->AddRef();
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}
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}
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template <typename I>
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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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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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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::dom::OwningNonNull<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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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::dom::OwningNonNull<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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NS_ASSERTION(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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/*
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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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T*
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operator->() const MOZ_NO_ADDREF_RELEASE_ON_RETURN
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{
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NS_PRECONDITION(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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// This operator is needed for gcc <= 4.0.* and for Sun Studio; it
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// causes internal compiler errors for some MSVC versions. (It's not
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// clear to me whether it should be needed.)
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#ifndef _MSC_VER
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template <class U, class V>
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U&
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operator->*(U V::* aMember)
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{
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NS_PRECONDITION(mRawPtr != 0,
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"You can't dereference a NULL nsRefPtr with operator->*().");
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return get()->*aMember;
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}
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#endif
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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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NS_PRECONDITION(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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};
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template <class T>
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nsRefPtr<T>::nsRefPtr(const nsCOMPtr_helper& aHelper)
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{
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void* newRawPtr;
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if (NS_FAILED(aHelper(NS_GET_TEMPLATE_IID(T), &newRawPtr))) {
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newRawPtr = 0;
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}
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mRawPtr = static_cast<T*>(newRawPtr);
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}
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template <class T>
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nsRefPtr<T>&
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nsRefPtr<T>::operator=(const nsCOMPtr_helper& aHelper)
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{
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void* newRawPtr;
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if (NS_FAILED(aHelper(NS_GET_TEMPLATE_IID(T), &newRawPtr))) {
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newRawPtr = 0;
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}
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assign_assuming_AddRef(static_cast<T*>(newRawPtr));
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return *this;
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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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namespace detail {
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class nsRefPtrZero;
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}
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// Comparing an |nsRefPtr| to |0|
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template <class T>
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inline bool
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operator==(const nsRefPtr<T>& aLhs, ::detail::nsRefPtrZero* aRhs)
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// specifically to allow |smartPtr == 0|
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{
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return static_cast<const void*>(aLhs.get()) == reinterpret_cast<const void*>(aRhs);
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}
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template <class T>
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inline bool
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operator==(::detail::nsRefPtrZero* aLhs, const nsRefPtr<T>& aRhs)
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// specifically to allow |0 == smartPtr|
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{
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return reinterpret_cast<const void*>(aLhs) == static_cast<const void*>(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 nsRefPtr<T>& aLhs, ::detail::nsRefPtrZero* aRhs)
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// specifically to allow |smartPtr != 0|
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{
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return static_cast<const void*>(aLhs.get()) != reinterpret_cast<const void*>(aRhs);
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}
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template <class T>
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inline bool
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operator!=(::detail::nsRefPtrZero* aLhs, const nsRefPtr<T>& aRhs)
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// specifically to allow |0 != smartPtr|
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{
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return reinterpret_cast<const void*>(aLhs) != static_cast<const void*>(aRhs.get());
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}
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template <class SourceType, class DestinationType>
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inline nsresult
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CallQueryInterface(nsRefPtr<SourceType>& aSourcePtr, DestinationType** aDestPtr)
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{
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return CallQueryInterface(aSourcePtr.get(), aDestPtr);
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}
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/*****************************************************************************/
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template <class T>
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inline already_AddRefed<T>
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do_AddRef(T*&& aObj)
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{
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nsRefPtr<T> ref(aObj);
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return ref.forget();
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}
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#endif // !defined(nsRefPtr_h)
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