mirror of
https://github.com/mozilla/gecko-dev.git
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489 lines
12 KiB
C++
489 lines
12 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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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 nsHtml5RefPtr_h___
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#define nsHtml5RefPtr_h___
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#include "nsIThread.h"
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template <class T>
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class nsHtml5RefPtrReleaser : public nsRunnable
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{
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private:
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T* mPtr;
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public:
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nsHtml5RefPtrReleaser(T* aPtr)
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: mPtr(aPtr)
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{}
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NS_IMETHODIMP Run()
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{
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mPtr->Release();
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return NS_OK;
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}
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};
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// template <class T> class nsHtml5RefPtrGetterAddRefs;
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/**
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* Like nsRefPtr except release is proxied to the main thread. Mostly copied
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* from nsRefPtr.
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*/
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template <class T>
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class nsHtml5RefPtr
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{
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private:
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void
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assign_with_AddRef( T* rawPtr )
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{
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if ( rawPtr )
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rawPtr->AddRef();
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assign_assuming_AddRef(rawPtr);
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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* newPtr )
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{
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T* oldPtr = mRawPtr;
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mRawPtr = newPtr;
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if ( oldPtr )
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release(oldPtr);
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}
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void
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release( T* aPtr )
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{
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nsCOMPtr<nsIRunnable> releaser = new nsHtml5RefPtrReleaser<T>(aPtr);
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if (NS_FAILED(NS_DispatchToMainThread(releaser)))
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{
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NS_WARNING("Failed to dispatch releaser event.");
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}
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}
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private:
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T* mRawPtr;
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public:
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typedef T element_type;
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~nsHtml5RefPtr()
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{
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if ( mRawPtr )
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release(mRawPtr);
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}
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// Constructors
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nsHtml5RefPtr()
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: mRawPtr(0)
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// default constructor
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{
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}
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nsHtml5RefPtr( const nsHtml5RefPtr<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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nsHtml5RefPtr( T* 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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if ( mRawPtr )
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mRawPtr->AddRef();
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}
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nsHtml5RefPtr( const already_AddRefed<T>& aSmartPtr )
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: mRawPtr(aSmartPtr.mRawPtr)
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// construct from |dont_AddRef(expr)|
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{
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}
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// Assignment operators
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nsHtml5RefPtr<T>&
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operator=( const nsHtml5RefPtr<T>& rhs )
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// copy assignment operator
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{
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assign_with_AddRef(rhs.mRawPtr);
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return *this;
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}
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nsHtml5RefPtr<T>&
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operator=( T* rhs )
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// assign from a raw pointer (of the right type)
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{
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assign_with_AddRef(rhs);
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return *this;
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}
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nsHtml5RefPtr<T>&
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operator=( const already_AddRefed<T>& rhs )
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// assign from |dont_AddRef(expr)|
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{
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assign_assuming_AddRef(rhs.mRawPtr);
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return *this;
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}
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// Other pointer operators
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void
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swap( nsHtml5RefPtr<T>& rhs )
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// ...exchange ownership with |rhs|; can save a pair of refcount operations
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{
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T* temp = rhs.mRawPtr;
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rhs.mRawPtr = mRawPtr;
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mRawPtr = temp;
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}
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void
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swap( T*& rhs )
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// ...exchange ownership with |rhs|; can save a pair of refcount operations
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{
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T* temp = rhs;
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rhs = 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 temp;
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}
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template <typename I>
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void
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forget( I** rhs)
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// Set the target of rhs 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 rhs 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(rhs, "Null pointer passed to forget!");
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*rhs = 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 |nsHtml5RefPtr| 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 |nsHtml5RefPtr| 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
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{
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NS_PRECONDITION(mRawPtr != 0, "You can't dereference a NULL nsHtml5RefPtr with operator->().");
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return get();
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}
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nsHtml5RefPtr<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 nsHtml5RefPtr<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, "You can't dereference a NULL nsHtml5RefPtr 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_assuming_AddRef(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
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nsHtml5RefPtr<T>*
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address_of( nsHtml5RefPtr<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
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const nsHtml5RefPtr<T>*
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address_of( const nsHtml5RefPtr<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 nsHtml5RefPtrGetterAddRefs
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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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nsHtml5RefPtr<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 |nsHtml5RefPtr|, 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 |nsHtml5RefPtr<T>|.
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*/
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{
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public:
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explicit
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nsHtml5RefPtrGetterAddRefs( nsHtml5RefPtr<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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nsHtml5RefPtr<T>& mTargetSmartPtr;
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};
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template <class T>
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inline
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nsHtml5RefPtrGetterAddRefs<T>
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getter_AddRefs( nsHtml5RefPtr<T>& aSmartPtr )
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/*
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Used around a |nsHtml5RefPtr| when
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...makes the class |nsHtml5RefPtrGetterAddRefs<T>| invisible.
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*/
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{
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return nsHtml5RefPtrGetterAddRefs<T>(aSmartPtr);
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}
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// Comparing two |nsHtml5RefPtr|s
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template <class T, class U>
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inline
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bool
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operator==( const nsHtml5RefPtr<T>& lhs, const nsHtml5RefPtr<U>& rhs )
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{
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return static_cast<const T*>(lhs.get()) == static_cast<const U*>(rhs.get());
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}
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template <class T, class U>
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inline
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bool
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operator!=( const nsHtml5RefPtr<T>& lhs, const nsHtml5RefPtr<U>& rhs )
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{
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return static_cast<const T*>(lhs.get()) != static_cast<const U*>(rhs.get());
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}
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// Comparing an |nsHtml5RefPtr| to a raw pointer
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template <class T, class U>
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inline
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bool
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operator==( const nsHtml5RefPtr<T>& lhs, const U* rhs )
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{
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return static_cast<const T*>(lhs.get()) == static_cast<const U*>(rhs);
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}
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template <class T, class U>
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inline
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bool
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operator==( const U* lhs, const nsHtml5RefPtr<T>& rhs )
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{
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return static_cast<const U*>(lhs) == static_cast<const T*>(rhs.get());
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}
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template <class T, class U>
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inline
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bool
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operator!=( const nsHtml5RefPtr<T>& lhs, const U* rhs )
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{
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return static_cast<const T*>(lhs.get()) != static_cast<const U*>(rhs);
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}
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template <class T, class U>
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inline
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bool
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operator!=( const U* lhs, const nsHtml5RefPtr<T>& rhs )
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{
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return static_cast<const U*>(lhs) != static_cast<const T*>(rhs.get());
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}
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// To avoid ambiguities caused by the presence of builtin |operator==|s
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// creating a situation where one of the |operator==| defined above
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// has a better conversion for one argument and the builtin has a
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// better conversion for the other argument, define additional
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// |operator==| without the |const| on the raw pointer.
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// See bug 65664 for details.
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#ifndef NSCAP_DONT_PROVIDE_NONCONST_OPEQ
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template <class T, class U>
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inline
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bool
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operator==( const nsHtml5RefPtr<T>& lhs, U* rhs )
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{
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return static_cast<const T*>(lhs.get()) == const_cast<const U*>(rhs);
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}
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template <class T, class U>
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inline
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bool
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operator==( U* lhs, const nsHtml5RefPtr<T>& rhs )
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{
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return const_cast<const U*>(lhs) == static_cast<const T*>(rhs.get());
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}
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template <class T, class U>
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inline
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bool
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operator!=( const nsHtml5RefPtr<T>& lhs, U* rhs )
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{
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return static_cast<const T*>(lhs.get()) != const_cast<const U*>(rhs);
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}
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template <class T, class U>
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inline
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bool
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operator!=( U* lhs, const nsHtml5RefPtr<T>& rhs )
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{
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return const_cast<const U*>(lhs) != static_cast<const T*>(rhs.get());
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}
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#endif
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// Comparing an |nsHtml5RefPtr| to |0|
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template <class T>
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inline
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bool
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operator==( const nsHtml5RefPtr<T>& lhs, NSCAP_Zero* rhs )
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// specifically to allow |smartPtr == 0|
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{
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return static_cast<const void*>(lhs.get()) == reinterpret_cast<const void*>(rhs);
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}
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template <class T>
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inline
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bool
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operator==( NSCAP_Zero* lhs, const nsHtml5RefPtr<T>& rhs )
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// specifically to allow |0 == smartPtr|
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{
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return reinterpret_cast<const void*>(lhs) == static_cast<const void*>(rhs.get());
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}
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template <class T>
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inline
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bool
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operator!=( const nsHtml5RefPtr<T>& lhs, NSCAP_Zero* rhs )
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// specifically to allow |smartPtr != 0|
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{
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return static_cast<const void*>(lhs.get()) != reinterpret_cast<const void*>(rhs);
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}
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template <class T>
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inline
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bool
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operator!=( NSCAP_Zero* lhs, const nsHtml5RefPtr<T>& rhs )
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// specifically to allow |0 != smartPtr|
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{
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return reinterpret_cast<const void*>(lhs) != static_cast<const void*>(rhs.get());
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}
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#ifdef HAVE_CPP_TROUBLE_COMPARING_TO_ZERO
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// We need to explicitly define comparison operators for `int'
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// because the compiler is lame.
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template <class T>
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inline
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bool
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operator==( const nsHtml5RefPtr<T>& lhs, int rhs )
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// specifically to allow |smartPtr == 0|
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{
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return static_cast<const void*>(lhs.get()) == reinterpret_cast<const void*>(rhs);
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}
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template <class T>
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inline
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bool
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operator==( int lhs, const nsHtml5RefPtr<T>& rhs )
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// specifically to allow |0 == smartPtr|
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{
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return reinterpret_cast<const void*>(lhs) == static_cast<const void*>(rhs.get());
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}
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#endif // !defined(HAVE_CPP_TROUBLE_COMPARING_TO_ZERO)
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#endif // !defined(nsHtml5RefPtr_h___)
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