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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /dom/base/nsStubDocumentObserver.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'dom/base/nsStubDocumentObserver.h')
-rw-r--r--dom/base/nsStubDocumentObserver.h35
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diff --git a/dom/base/nsStubDocumentObserver.h b/dom/base/nsStubDocumentObserver.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * nsStubDocumentObserver is an implementation of the nsIDocumentObserver
+ * interface (except for the methods on nsISupports) that is intended to be
+ * used as a base class within the content/layout library. All methods do
+ * nothing.
+ */
+
+#ifndef nsStubDocumentObserver_h_
+#define nsStubDocumentObserver_h_
+
+#include "nsIDocumentObserver.h"
+
+/**
+ * There are two advantages to inheriting from nsStubDocumentObserver
+ * rather than directly from nsIDocumentObserver:
+ * 1. smaller compiled code size (since there's no need for the code
+ * for the empty virtual function implementations for every
+ * nsIDocumentObserver implementation)
+ * 2. the performance of document's loop over observers benefits from
+ * the fact that more of the functions called are the same (which
+ * can reduce instruction cache misses and perhaps improve branch
+ * prediction)
+ */
+class nsStubDocumentObserver : public nsIDocumentObserver {
+public:
+ NS_DECL_NSIDOCUMENTOBSERVER
+};
+
+#endif /* !defined(nsStubDocumentObserver_h_) */