gecko-dev/xpcom/base/nsCycleCollectionNoteChild.h

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/* -*- 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/. */
// This header will be included by headers that define refpointer and array
// classes in order to specialize CC helpers such as ImplCycleCollectionTraverse
// for them.
#ifndef nsCycleCollectionNoteChild_h__
#define nsCycleCollectionNoteChild_h__
#include "nsCycleCollectionTraversalCallback.h"
#include "mozilla/Likely.h"
#include "mozilla/TypeTraits.h"
enum { CycleCollectionEdgeNameArrayFlag = 1 };
// Just a helper for appending "[i]". Didn't want to pull in string headers
// here.
void CycleCollectionNoteEdgeNameImpl(
nsCycleCollectionTraversalCallback& aCallback, const char* aName,
uint32_t aFlags = 0);
// Should be inlined so that in the no-debug-info case this is just a simple
// if().
MOZ_ALWAYS_INLINE void CycleCollectionNoteEdgeName(
nsCycleCollectionTraversalCallback& aCallback, const char* aName,
uint32_t aFlags = 0) {
if (MOZ_UNLIKELY(aCallback.WantDebugInfo())) {
CycleCollectionNoteEdgeNameImpl(aCallback, aName, aFlags);
}
}
#define NS_CYCLE_COLLECTION_INNERCLASS cycleCollection
#define NS_CYCLE_COLLECTION_INNERNAME _cycleCollectorGlobal
#define NS_CYCLE_COLLECTION_PARTICIPANT(_class) \
_class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()
template <typename T>
nsISupports* ToSupports(
T* aPtr, typename T::NS_CYCLE_COLLECTION_INNERCLASS* aDummy = 0) {
return T::NS_CYCLE_COLLECTION_INNERCLASS::Upcast(aPtr);
}
// The default implementation of this class template is empty, because it
// should never be used: see the partial specializations below.
template <typename T, bool IsXPCOM = mozilla::IsBaseOf<nsISupports, T>::value>
struct CycleCollectionNoteChildImpl {};
template <typename T>
struct CycleCollectionNoteChildImpl<T, true> {
static void Run(nsCycleCollectionTraversalCallback& aCallback, T* aChild) {
aCallback.NoteXPCOMChild(ToSupports(aChild));
}
};
template <typename T>
struct CycleCollectionNoteChildImpl<T, false> {
static void Run(nsCycleCollectionTraversalCallback& aCallback, T* aChild) {
aCallback.NoteNativeChild(aChild, NS_CYCLE_COLLECTION_PARTICIPANT(T));
}
};
// We declare CycleCollectionNoteChild in 3-argument and 4-argument variants,
// rather than using default arguments, so that forward declarations work
// regardless of header inclusion order.
template <typename T>
inline void CycleCollectionNoteChild(
nsCycleCollectionTraversalCallback& aCallback, T* aChild, const char* aName,
uint32_t aFlags) {
CycleCollectionNoteEdgeName(aCallback, aName, aFlags);
CycleCollectionNoteChildImpl<T>::Run(aCallback, aChild);
}
template <typename T>
inline void CycleCollectionNoteChild(
nsCycleCollectionTraversalCallback& aCallback, T* aChild,
const char* aName) {
CycleCollectionNoteChild(aCallback, aChild, aName, 0);
}
#endif // nsCycleCollectionNoteChild_h__