mirror of
https://github.com/mozilla/gecko-dev.git
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117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Places code.
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*
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* The Initial Developer of the Original Code is
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* Google Inc.
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* Portions created by the Initial Developer are Copyright (C) 2005
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Brian Ryner <bryner@brianryner.com> (original author)
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsMaybeWeakPtr_h_
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#define nsMaybeWeakPtr_h_
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#include "nsCOMPtr.h"
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#include "nsWeakReference.h"
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#include "nsTArray.h"
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// nsMaybeWeakPtr is a helper object to hold a strong-or-weak reference
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// to the template class. It's pretty minimal, but sufficient.
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class nsMaybeWeakPtr_base
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{
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protected:
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// Returns an addref'd pointer to the requested interface
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void* GetValueAs(const nsIID& iid) const;
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nsCOMPtr<nsISupports> mPtr;
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};
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template<class T>
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class nsMaybeWeakPtr : private nsMaybeWeakPtr_base
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{
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public:
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nsMaybeWeakPtr(nsISupports *ref) { mPtr = ref; }
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nsMaybeWeakPtr(const nsCOMPtr<nsIWeakReference> &ref) { mPtr = ref; }
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nsMaybeWeakPtr(const nsCOMPtr<T> &ref) { mPtr = ref; }
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bool operator==(const nsMaybeWeakPtr<T> &other) const {
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return mPtr == other.mPtr;
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}
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operator const nsCOMPtr<T>() const { return GetValue(); }
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protected:
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const nsCOMPtr<T> GetValue() const {
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return nsCOMPtr<T>(dont_AddRef(static_cast<T*>
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(GetValueAs(NS_GET_TEMPLATE_IID(T)))));
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}
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};
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// nsMaybeWeakPtrArray is an array of MaybeWeakPtr objects, that knows how to
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// grab a weak reference to a given object if requested. It only allows a
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// given object to appear in the array once.
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typedef nsTArray< nsMaybeWeakPtr<nsISupports> > isupports_array_type;
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nsresult NS_AppendWeakElementBase(isupports_array_type *aArray,
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nsISupports *aElement, bool aWeak);
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nsresult NS_RemoveWeakElementBase(isupports_array_type *aArray,
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nsISupports *aElement);
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template<class T>
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class nsMaybeWeakPtrArray : public nsTArray< nsMaybeWeakPtr<T> >
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{
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public:
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nsresult AppendWeakElement(T *aElement, bool aOwnsWeak)
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{
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return NS_AppendWeakElementBase(
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reinterpret_cast<isupports_array_type*>(this), aElement, aOwnsWeak);
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}
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nsresult RemoveWeakElement(T *aElement)
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{
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return NS_RemoveWeakElementBase(
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reinterpret_cast<isupports_array_type*>(this), aElement);
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}
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};
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// Call a method on each element in the array, but only if the element is
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// non-null.
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#define ENUMERATE_WEAKARRAY(array, type, method) \
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for (PRUint32 array_idx = 0; array_idx < array.Length(); ++array_idx) { \
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const nsCOMPtr<type> &e = array.ElementAt(array_idx); \
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if (e) \
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e->method; \
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}
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#endif
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