gecko-dev/toolkit/components/places/nsMaybeWeakPtr.h
Michael Wu d2b70213ac Bug 675553 - Switch from PRBool to bool on a CLOSED TREE , r=bsmedberg,khuey,bz,cjones
--HG--
rename : tools/trace-malloc/bloatblame.c => tools/trace-malloc/bloatblame.cpp
2011-09-28 23:19:26 -07:00

117 lines
4.2 KiB
C++

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