From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- xpcom/glue/nsIWeakReferenceUtils.h | 102 +++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 xpcom/glue/nsIWeakReferenceUtils.h (limited to 'xpcom/glue/nsIWeakReferenceUtils.h') diff --git a/xpcom/glue/nsIWeakReferenceUtils.h b/xpcom/glue/nsIWeakReferenceUtils.h new file mode 100644 index 000000000..1c84e00df --- /dev/null +++ b/xpcom/glue/nsIWeakReferenceUtils.h @@ -0,0 +1,102 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef nsIWeakReferenceUtils_h__ +#define nsIWeakReferenceUtils_h__ + +#include "nsCOMPtr.h" +#include "nsIWeakReference.h" + +typedef nsCOMPtr nsWeakPtr; + +/** + * + */ + +// a type-safe shortcut for calling the |QueryReferent()| member function +// T must inherit from nsIWeakReference, but the cast may be ambiguous. +template +inline nsresult +CallQueryReferent(T* aSource, DestinationType** aDestination) +{ + NS_PRECONDITION(aSource, "null parameter"); + NS_PRECONDITION(aDestination, "null parameter"); + + return aSource->QueryReferent(NS_GET_TEMPLATE_IID(DestinationType), + reinterpret_cast(aDestination)); +} + + +class MOZ_STACK_CLASS nsQueryReferent final : public nsCOMPtr_helper +{ +public: + nsQueryReferent(nsIWeakReference* aWeakPtr, nsresult* aError) + : mWeakPtr(aWeakPtr) + , mErrorPtr(aError) + { + } + + virtual nsresult NS_FASTCALL operator()(const nsIID& aIID, void**) const + override; + +private: + nsIWeakReference* MOZ_NON_OWNING_REF mWeakPtr; + nsresult* mErrorPtr; +}; + +inline const nsQueryReferent +do_QueryReferent(nsIWeakReference* aRawPtr, nsresult* aError = 0) +{ + return nsQueryReferent(aRawPtr, aError); +} + + +/** + * Deprecated, use |do_GetWeakReference| instead. + */ +extern nsIWeakReference* NS_GetWeakReference(nsISupports*, + nsresult* aResult = 0); + +/** + * |do_GetWeakReference| is a convenience function that bundles up all the work needed + * to get a weak reference to an arbitrary object, i.e., the |QueryInterface|, test, and + * call through to |GetWeakReference|, and put it into your |nsCOMPtr|. + * It is specifically designed to cooperate with |nsCOMPtr| (or |nsWeakPtr|) like so: + * |nsWeakPtr myWeakPtr = do_GetWeakReference(aPtr);|. + */ +inline already_AddRefed +do_GetWeakReference(nsISupports* aRawPtr, nsresult* aError = 0) +{ + return dont_AddRef(NS_GetWeakReference(aRawPtr, aError)); +} + +inline void +do_GetWeakReference(nsIWeakReference* aRawPtr, nsresult* aError = 0) +{ + // This signature exists solely to _stop_ you from doing a bad thing. + // Saying |do_GetWeakReference()| on a weak reference itself, + // is very likely to be a programmer error. +} + +template +inline void +do_GetWeakReference(already_AddRefed&) +{ + // This signature exists solely to _stop_ you from doing the bad thing. + // Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by + // someone else is an automatic leak. See . +} + +template +inline void +do_GetWeakReference(already_AddRefed&, nsresult*) +{ + // This signature exists solely to _stop_ you from doing the bad thing. + // Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by + // someone else is an automatic leak. See . +} + +#endif -- cgit v1.2.3