1 : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* ***** BEGIN LICENSE BLOCK *****
3 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 : *
5 : * The contents of this file are subject to the Mozilla Public License Version
6 : * 1.1 (the "License"); you may not use this file except in compliance with
7 : * the License. You may obtain a copy of the License at
8 : * http://www.mozilla.org/MPL/
9 : *
10 : * Software distributed under the License is distributed on an "AS IS" basis,
11 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 : * for the specific language governing rights and limitations under the
13 : * License.
14 : *
15 : * The Original Code is Places code.
16 : *
17 : * The Initial Developer of the Original Code is
18 : * Google Inc.
19 : * Portions created by the Initial Developer are Copyright (C) 2005
20 : * the Initial Developer. All Rights Reserved.
21 : *
22 : * Contributor(s):
23 : * Brian Ryner <bryner@brianryner.com> (original author)
24 : *
25 : * Alternatively, the contents of this file may be used under the terms of
26 : * either the GNU General Public License Version 2 or later (the "GPL"), or
27 : * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 : * in which case the provisions of the GPL or the LGPL are applicable instead
29 : * of those above. If you wish to allow use of your version of this file only
30 : * under the terms of either the GPL or the LGPL, and not to allow others to
31 : * use your version of this file under the terms of the MPL, indicate your
32 : * decision by deleting the provisions above and replace them with the notice
33 : * and other provisions required by the GPL or the LGPL. If you do not delete
34 : * the provisions above, a recipient may use your version of this file under
35 : * the terms of any one of the MPL, the GPL or the LGPL.
36 : *
37 : * ***** END LICENSE BLOCK ***** */
38 :
39 : #ifndef nsMaybeWeakPtr_h_
40 : #define nsMaybeWeakPtr_h_
41 :
42 : #include "nsCOMPtr.h"
43 : #include "nsWeakReference.h"
44 : #include "nsTArray.h"
45 :
46 : // nsMaybeWeakPtr is a helper object to hold a strong-or-weak reference
47 : // to the template class. It's pretty minimal, but sufficient.
48 :
49 : class nsMaybeWeakPtr_base
50 15796 : {
51 : protected:
52 : // Returns an addref'd pointer to the requested interface
53 : void* GetValueAs(const nsIID& iid) const;
54 :
55 : nsCOMPtr<nsISupports> mPtr;
56 : };
57 :
58 : template<class T>
59 : class nsMaybeWeakPtr : private nsMaybeWeakPtr_base
60 7898 : {
61 : public:
62 2592 : nsMaybeWeakPtr(nsISupports *ref) { mPtr = ref; }
63 2407 : nsMaybeWeakPtr(const nsCOMPtr<nsIWeakReference> &ref) { mPtr = ref; }
64 2899 : nsMaybeWeakPtr(const nsCOMPtr<T> &ref) { mPtr = ref; }
65 :
66 6418 : bool operator==(const nsMaybeWeakPtr<T> &other) const {
67 6418 : return mPtr == other.mPtr;
68 : }
69 :
70 14583 : operator const nsCOMPtr<T>() const { return GetValue(); }
71 :
72 : protected:
73 14583 : const nsCOMPtr<T> GetValue() const {
74 : return nsCOMPtr<T>(dont_AddRef(static_cast<T*>
75 14583 : (GetValueAs(NS_GET_TEMPLATE_IID(T)))));
76 : }
77 : };
78 :
79 : // nsMaybeWeakPtrArray is an array of MaybeWeakPtr objects, that knows how to
80 : // grab a weak reference to a given object if requested. It only allows a
81 : // given object to appear in the array once.
82 :
83 : typedef nsTArray< nsMaybeWeakPtr<nsISupports> > isupports_array_type;
84 : nsresult NS_AppendWeakElementBase(isupports_array_type *aArray,
85 : nsISupports *aElement, bool aWeak);
86 : nsresult NS_RemoveWeakElementBase(isupports_array_type *aArray,
87 : nsISupports *aElement);
88 :
89 : template<class T>
90 : class nsMaybeWeakPtrArray : public nsTArray< nsMaybeWeakPtr<T> >
91 4532 : {
92 : public:
93 1480 : nsresult AppendWeakElement(T *aElement, bool aOwnsWeak)
94 : {
95 : return NS_AppendWeakElementBase(
96 1480 : reinterpret_cast<isupports_array_type*>(this), aElement, aOwnsWeak);
97 : }
98 :
99 1211 : nsresult RemoveWeakElement(T *aElement)
100 : {
101 : return NS_RemoveWeakElementBase(
102 1211 : reinterpret_cast<isupports_array_type*>(this), aElement);
103 : }
104 : };
105 :
106 : // Call a method on each element in the array, but only if the element is
107 : // non-null.
108 :
109 : #define ENUMERATE_WEAKARRAY(array, type, method) \
110 : for (PRUint32 array_idx = 0; array_idx < array.Length(); ++array_idx) { \
111 : const nsCOMPtr<type> &e = array.ElementAt(array_idx); \
112 : if (e) \
113 : e->method; \
114 : }
115 :
116 : #endif
|