1 files changed, 107 insertions, 0 deletions
diff --git a/dom/events/AsyncEventDispatcher.h b/dom/events/AsyncEventDispatcher.h
new file mode 100644
index 000000000..094e764b6
--- /dev/null
+++ b/dom/events/AsyncEventDispatcher.h
@@ -0,0 +1,107 @@
+/* -*- 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/. */
+
+#ifndef mozilla_AsyncEventDispatcher_h_
+#define mozilla_AsyncEventDispatcher_h_
+
+#include "mozilla/Attributes.h"
+#include "nsCOMPtr.h"
+#include "nsIDocument.h"
+#include "nsIDOMEvent.h"
+#include "nsString.h"
+#include "nsThreadUtils.h"
+
+class nsINode;
+
+namespace mozilla {
+
+/**
+ * Use AsyncEventDispatcher to fire a DOM event that requires safe a stable DOM.
+ * For example, you may need to fire an event from within layout, but
+ * want to ensure that the event handler doesn't mutate the DOM at
+ * the wrong time, in order to avoid resulting instability.
+ */
+
+class AsyncEventDispatcher : public CancelableRunnable
+{
+public:
+  /**
+   * If aOnlyChromeDispatch is true, the event is dispatched to only
+   * chrome node. In that case, if aTarget is already a chrome node,
+   * the event is dispatched to it, otherwise the dispatch path starts
+   * at the first chrome ancestor of that target.
+   */
+  AsyncEventDispatcher(nsINode* aTarget, const nsAString& aEventType,
+                       bool aBubbles, bool aOnlyChromeDispatch)
+    : mTarget(aTarget)
+    , mEventType(aEventType)
+    , mBubbles(aBubbles)
+    , mOnlyChromeDispatch(aOnlyChromeDispatch)
+  {
+  }
+
+  AsyncEventDispatcher(dom::EventTarget* aTarget, const nsAString& aEventType,
+                       bool aBubbles)
+    : mTarget(aTarget)
+    , mEventType(aEventType)
+    , mBubbles(aBubbles)
+  {
+  }
+
+  AsyncEventDispatcher(dom::EventTarget* aTarget, nsIDOMEvent* aEvent)
+    : mTarget(aTarget)
+    , mEvent(aEvent)
+  {
+  }
+
+  AsyncEventDispatcher(dom::EventTarget* aTarget, WidgetEvent& aEvent);
+
+  NS_IMETHOD Run() override;
+  nsresult Cancel() override;
+  nsresult PostDOMEvent();
+  void RunDOMEventWhenSafe();
+
+  nsCOMPtr<dom::EventTarget> mTarget;
+  nsCOMPtr<nsIDOMEvent> mEvent;
+  nsString              mEventType;
+  bool                  mBubbles = false;
+  bool                  mOnlyChromeDispatch = false;
+  bool                  mCanceled = false;
+};
+
+class LoadBlockingAsyncEventDispatcher final : public AsyncEventDispatcher
+{
+public:
+  LoadBlockingAsyncEventDispatcher(nsINode* aEventNode,
+                                   const nsAString& aEventType,
+                                   bool aBubbles, bool aDispatchChromeOnly)
+    : AsyncEventDispatcher(aEventNode, aEventType,
+                           aBubbles, aDispatchChromeOnly)
+    , mBlockedDoc(aEventNode->OwnerDoc())
+  {
+    if (mBlockedDoc) {
+      mBlockedDoc->BlockOnload();
+    }
+  }
+
+  LoadBlockingAsyncEventDispatcher(nsINode* aEventNode, nsIDOMEvent* aEvent)
+    : AsyncEventDispatcher(aEventNode, aEvent)
+    , mBlockedDoc(aEventNode->OwnerDoc())
+  {
+    if (mBlockedDoc) {
+      mBlockedDoc->BlockOnload();
+    }
+  }
+
+  ~LoadBlockingAsyncEventDispatcher();
+
+private:
+  nsCOMPtr<nsIDocument> mBlockedDoc;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_AsyncEventDispatcher_h_