1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/components/places/nsMaybeWeakPtr.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,105 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsMaybeWeakPtr_h_
1.10 +#define nsMaybeWeakPtr_h_
1.11 +
1.12 +#include "nsCOMPtr.h"
1.13 +#include "nsWeakReference.h"
1.14 +#include "nsTArray.h"
1.15 +#include "nsCycleCollectionNoteChild.h"
1.16 +
1.17 +// nsMaybeWeakPtr is a helper object to hold a strong-or-weak reference
1.18 +// to the template class. It's pretty minimal, but sufficient.
1.19 +
1.20 +class nsMaybeWeakPtr_base
1.21 +{
1.22 +protected:
1.23 + // Returns an addref'd pointer to the requested interface
1.24 + void* GetValueAs(const nsIID& iid) const;
1.25 +
1.26 + nsCOMPtr<nsISupports> mPtr;
1.27 +};
1.28 +
1.29 +template<class T>
1.30 +class nsMaybeWeakPtr : private nsMaybeWeakPtr_base
1.31 +{
1.32 +public:
1.33 + nsMaybeWeakPtr(nsISupports *ref) { mPtr = ref; }
1.34 + nsMaybeWeakPtr(const nsCOMPtr<nsIWeakReference> &ref) { mPtr = ref; }
1.35 + nsMaybeWeakPtr(const nsCOMPtr<T> &ref) { mPtr = ref; }
1.36 +
1.37 + bool operator==(const nsMaybeWeakPtr<T> &other) const {
1.38 + return mPtr == other.mPtr;
1.39 + }
1.40 +
1.41 + operator const nsCOMPtr<T>() const { return GetValue(); }
1.42 +
1.43 +protected:
1.44 + const nsCOMPtr<T> GetValue() const {
1.45 + return nsCOMPtr<T>(dont_AddRef(static_cast<T*>
1.46 + (GetValueAs(NS_GET_TEMPLATE_IID(T)))));
1.47 + }
1.48 +};
1.49 +
1.50 +// nsMaybeWeakPtrArray is an array of MaybeWeakPtr objects, that knows how to
1.51 +// grab a weak reference to a given object if requested. It only allows a
1.52 +// given object to appear in the array once.
1.53 +
1.54 +typedef nsTArray< nsMaybeWeakPtr<nsISupports> > isupports_array_type;
1.55 +nsresult NS_AppendWeakElementBase(isupports_array_type *aArray,
1.56 + nsISupports *aElement, bool aWeak);
1.57 +nsresult NS_RemoveWeakElementBase(isupports_array_type *aArray,
1.58 + nsISupports *aElement);
1.59 +
1.60 +template<class T>
1.61 +class nsMaybeWeakPtrArray : public nsTArray< nsMaybeWeakPtr<T> >
1.62 +{
1.63 +public:
1.64 + nsresult AppendWeakElement(T *aElement, bool aOwnsWeak)
1.65 + {
1.66 + return NS_AppendWeakElementBase(
1.67 + reinterpret_cast<isupports_array_type*>(this), aElement, aOwnsWeak);
1.68 + }
1.69 +
1.70 + nsresult RemoveWeakElement(T *aElement)
1.71 + {
1.72 + return NS_RemoveWeakElementBase(
1.73 + reinterpret_cast<isupports_array_type*>(this), aElement);
1.74 + }
1.75 +};
1.76 +
1.77 +template <typename T>
1.78 +inline void
1.79 +ImplCycleCollectionUnlink(nsMaybeWeakPtrArray<T>& aField)
1.80 +{
1.81 + aField.Clear();
1.82 +}
1.83 +
1.84 +template <typename E>
1.85 +inline void
1.86 +ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
1.87 + nsMaybeWeakPtrArray<E>& aField,
1.88 + const char* aName,
1.89 + uint32_t aFlags = 0)
1.90 +{
1.91 + aFlags |= CycleCollectionEdgeNameArrayFlag;
1.92 + size_t length = aField.Length();
1.93 + for (size_t i = 0; i < length; ++i) {
1.94 + CycleCollectionNoteChild(aCallback, aField[i].get(), aName, aFlags);
1.95 + }
1.96 +}
1.97 +
1.98 +// Call a method on each element in the array, but only if the element is
1.99 +// non-null.
1.100 +
1.101 +#define ENUMERATE_WEAKARRAY(array, type, method) \
1.102 + for (uint32_t array_idx = 0; array_idx < array.Length(); ++array_idx) { \
1.103 + const nsCOMPtr<type> &e = array.ElementAt(array_idx); \
1.104 + if (e) \
1.105 + e->method; \
1.106 + }
1.107 +
1.108 +#endif
