1 files changed, 93 insertions, 0 deletions
diff --git a/xpcom/ds/nsObserverList.cpp b/xpcom/ds/nsObserverList.cpp
new file mode 100644
index 0000000000..4f21c4fcc9
--- /dev/null
+++ b/xpcom/ds/nsObserverList.cpp
@@ -0,0 +1,93 @@
+/* -*- 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 "mozilla/Try.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;
+}