Index: gecko-sdk/idl/nsIPrefBranch2.idl |
=================================================================== |
--- gecko-sdk/idl/nsIPrefBranch2.idl (revision 0) |
+++ gecko-sdk/idl/nsIPrefBranch2.idl (revision 0) |
@@ -0,0 +1,114 @@ |
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
+/* ***** BEGIN LICENSE BLOCK ***** |
+ * Version: NPL 1.1/GPL 2.0/LGPL 2.1 |
+ * |
+ * The contents of this file are subject to the Netscape 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/NPL/ |
+ * |
+ * 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 Mozilla Communicator client code. |
+ * |
+ * The Initial Developer of the Original Code is |
+ * Netscape Communications Corporation. |
+ * Portions created by the Initial Developer are Copyright (C) 1998 |
+ * the Initial Developer. All Rights Reserved. |
+ * |
+ * Contributor(s): |
+ * Alec Flett <alecf@netscape.com> |
+ * Brian Nesse <bnesse@netscape.com> |
+ * Benjamin Smedberg <benjamin@smedbergs.us> |
+ * |
+ * 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 NPL, 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 NPL, the GPL or the LGPL. |
+ * |
+ * ***** END LICENSE BLOCK ***** */ |
+ |
+#include "nsIPrefBranch.idl" |
+ |
+interface nsIObserver; |
+ |
+/** |
+ * nsIPrefBranch2 allows clients to observe changes to pref values. |
+ * |
+ * @status FROZEN |
+ * @see nsIPrefBranch |
+ */ |
+[scriptable, uuid(74567534-eb94-4b1c-8f45-389643bfc555)] |
+interface nsIPrefBranch2 : nsIPrefBranch |
+{ |
+ /** |
+ * Add a preference change observer. On preference changes, the following |
+ * arguments will be passed to the nsIObserver.observe() method: |
+ * aSubject - The nsIPrefBranch object (this) |
+ * aTopic - The string defined by NS_PREFBRANCH_PREFCHANGE_TOPIC_ID |
+ * aData - The preference which has changed |
+ * |
+ * @param aDomain The preference on which to listen for changes. This can |
+ * be the name of an entire branch to observe. |
+ * e.g. Holding the "root" prefbranch and calling |
+ * addObserver("foo.bar.", ...) will observe changes to |
+ * foo.bar.baz and foo.bar.bzip |
+ * @param aObserver The object to be notified if the preference changes. |
+ * @param aHoldWeak true Hold a weak reference to |aObserver|. The object |
+ * must implement the nsISupportsWeakReference |
+ * interface or this will fail. |
+ * false Hold a strong reference to |aObserver|. |
+ * |
+ * @note |
+ * Registering as a preference observer can open an object to potential |
+ * cyclical references which will cause memory leaks. These cycles generally |
+ * occur because an object both registers itself as an observer (causing the |
+ * branch to hold a reference to the observer) and holds a reference to the |
+ * branch object for the purpose of getting/setting preference values. There |
+ * are 3 approaches which have been implemented in an attempt to avoid these |
+ * situations. |
+ * 1) The nsPrefBranch object supports nsISupportsWeakReference. Any consumer |
+ * may hold a weak reference to it instead of a strong one. |
+ * 2) The nsPrefBranch object listens for xpcom-shutdown and frees all of the |
+ * objects currently in its observer list. This insures that long lived |
+ * objects (services for example) will be freed correctly. |
+ * 3) The observer can request to be held as a weak reference when it is |
+ * registered. This insures that shorter lived objects (say one tied to an |
+ * open window) will not fall into the cyclical reference trap. |
+ * |
+ * @see nsIObserver |
+ * @see removeObserver |
+ */ |
+ void addObserver(in string aDomain, in nsIObserver aObserver, |
+ in boolean aHoldWeak); |
+ |
+ /** |
+ * Remove a preference change observer. |
+ * |
+ * @param aDomain The preference which is being observed for changes. |
+ * @param aObserver An observer previously registered with addObserver(). |
+ * |
+ * @see nsIObserver |
+ * @see addObserver |
+ */ |
+ void removeObserver(in string aDomain, in nsIObserver aObserver); |
+}; |
+ |
+%{C++ |
+ |
+/** |
+ * Notification sent when a preference changes. |
+ */ |
+#define NS_PREFBRANCH_PREFCHANGE_TOPIC_ID "nsPref:changed" |
+ |
+%} |
Property changes on: gecko-sdk\idl\nsIPrefBranch2.idl |
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Added: svn:eol-style |
+ LF |