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-rw-r--r--xpcom/ds/nsObserverList.cpp92
1 files changed, 92 insertions, 0 deletions
diff --git a/xpcom/ds/nsObserverList.cpp b/xpcom/ds/nsObserverList.cpp
new file mode 100644
index 0000000000..ba3eaaa2aa
--- /dev/null
+++ b/xpcom/ds/nsObserverList.cpp
@@ -0,0 +1,92 @@
+/* -*- 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/. */
+
+#include "nsObserverList.h"
+
+#include "mozilla/ResultExtensions.h"
+#include "nsCOMArray.h"
+#include "xpcpublic.h"
+
+nsresult nsObserverList::AddObserver(nsIObserver* anObserver, bool ownsWeak) {
+ NS_ASSERTION(anObserver, "Null input");
+
+ MOZ_TRY(mObservers.AppendWeakElement(anObserver, ownsWeak));
+ return NS_OK;
+}
+
+nsresult nsObserverList::RemoveObserver(nsIObserver* anObserver) {
+ NS_ASSERTION(anObserver, "Null input");
+
+ MOZ_TRY(mObservers.RemoveWeakElement(anObserver));
+ return NS_OK;
+}
+
+void nsObserverList::GetObserverList(nsISimpleEnumerator** anEnumerator) {
+ RefPtr<nsObserverEnumerator> e(new nsObserverEnumerator(this));
+ e.forget(anEnumerator);
+}
+
+nsCOMArray<nsIObserver> nsObserverList::ReverseCloneObserverArray() {
+ nsCOMArray<nsIObserver> array;
+ array.SetCapacity(mObservers.Length());
+
+ // XXX This could also use RemoveElementsBy if we lifted the promise to fill
+ // aArray in reverse order. Although there shouldn't be anyone explicitly
+ // relying on the order, changing this might cause subtle problems, so we
+ // better leave it as it is.
+
+ for (int32_t i = mObservers.Length() - 1; i >= 0; --i) {
+ nsCOMPtr<nsIObserver> observer = mObservers[i].GetValue();
+ if (observer) {
+ array.AppendElement(observer.forget());
+ } else {
+ // the object has gone away, remove the weakref
+ mObservers.RemoveElementAt(i);
+ }
+ }
+
+ return array;
+}
+
+void nsObserverList::AppendStrongObservers(nsCOMArray<nsIObserver>& aArray) {
+ aArray.SetCapacity(aArray.Length() + mObservers.Length());
+
+ for (int32_t i = mObservers.Length() - 1; i >= 0; --i) {
+ if (!mObservers[i].IsWeak()) {
+ nsCOMPtr<nsIObserver> observer = mObservers[i].GetValue();
+ aArray.AppendObject(observer);
+ }
+ }
+}
+
+void nsObserverList::NotifyObservers(nsISupports* aSubject, const char* aTopic,
+ const char16_t* someData) {
+ const nsCOMArray<nsIObserver> observers = ReverseCloneObserverArray();
+
+ for (int32_t i = 0; i < observers.Count(); ++i) {
+ observers[i]->Observe(aSubject, aTopic, someData);
+ }
+}
+
+nsObserverEnumerator::nsObserverEnumerator(nsObserverList* aObserverList)
+ : mIndex(0), mObservers(aObserverList->ReverseCloneObserverArray()) {}
+
+NS_IMETHODIMP
+nsObserverEnumerator::HasMoreElements(bool* aResult) {
+ *aResult = (mIndex < mObservers.Count());
+ return NS_OK;
+}
+
+NS_IMETHODIMP
+nsObserverEnumerator::GetNext(nsISupports** aResult) {
+ if (mIndex == mObservers.Count()) {
+ return NS_ERROR_FAILURE;
+ }
+
+ NS_ADDREF(*aResult = mObservers[mIndex]);
+ ++mIndex;
+ return NS_OK;
+}