1 files changed, 292 insertions, 0 deletions
diff --git a/dom/events/EventDispatcher.h b/dom/events/EventDispatcher.h
new file mode 100644
index 0000000000..3c754033db
--- /dev/null
+++ b/dom/events/EventDispatcher.h
@@ -0,0 +1,292 @@
+/* -*- 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/. */
+
+#ifdef MOZILLA_INTERNAL_API
+#ifndef mozilla_EventDispatcher_h_
+#define mozilla_EventDispatcher_h_
+
+#include "mozilla/EventForwards.h"
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+
+// Microsoft's API Name hackery sucks
+#undef CreateEvent
+
+class nsIContent;
+class nsIDOMEvent;
+class nsPresContext;
+
+template<class E> class nsCOMArray;
+
+namespace mozilla {
+namespace dom {
+class Event;
+class EventTarget;
+} // namespace dom
+
+/**
+ * About event dispatching:
+ * When either EventDispatcher::Dispatch or
+ * EventDispatcher::DispatchDOMEvent is called an event target chain is
+ * created. EventDispatcher creates the chain by calling PreHandleEvent 
+ * on each event target and the creation continues until either the mCanHandle
+ * member of the EventChainPreVisitor object is false or the mParentTarget
+ * does not point to a new target. The event target chain is created in the
+ * heap.
+ *
+ * If the event needs retargeting, mEventTargetAtParent must be set in
+ * PreHandleEvent.
+ *
+ * The capture, target and bubble phases of the event dispatch are handled
+ * by iterating through the event target chain. Iteration happens twice,
+ * first for the default event group and then for the system event group.
+ * While dispatching the event for the system event group PostHandleEvent
+ * is called right after calling event listener for the current event target.
+ */
+
+class EventChainVisitor
+{
+public:
+  EventChainVisitor(nsPresContext* aPresContext,
+                    WidgetEvent* aEvent,
+                    nsIDOMEvent* aDOMEvent,
+                    nsEventStatus aEventStatus = nsEventStatus_eIgnore)
+    : mPresContext(aPresContext)
+    , mEvent(aEvent)
+    , mDOMEvent(aDOMEvent)
+    , mEventStatus(aEventStatus)
+    , mItemFlags(0)
+  {
+  }
+
+  /**
+   * The prescontext, possibly nullptr.
+   */
+  nsPresContext* const  mPresContext;
+
+  /**
+   * The WidgetEvent which is being dispatched. Never nullptr.
+   */
+  WidgetEvent* const mEvent;
+
+  /**
+   * The DOM Event assiciated with the mEvent. Possibly nullptr if a DOM Event
+   * is not (yet) created.
+   */
+  nsIDOMEvent*          mDOMEvent;
+
+  /**
+   * The status of the event.
+   * @see nsEventStatus.h
+   */
+  nsEventStatus         mEventStatus;
+
+  /**
+   * Bits for items in the event target chain.
+   * Set in PreHandleEvent() and used in PostHandleEvent().
+   *
+   * @note These bits are different for each item in the event target chain.
+   *       It is up to the Pre/PostHandleEvent implementation to decide how to
+   *       use these bits.
+   *
+   * @note Using uint16_t because that is used also in EventTargetChainItem.
+   */
+  uint16_t              mItemFlags;
+
+  /**
+   * Data for items in the event target chain.
+   * Set in PreHandleEvent() and used in PostHandleEvent().
+   *
+   * @note This data is different for each item in the event target chain.
+   *       It is up to the Pre/PostHandleEvent implementation to decide how to
+   *       use this.
+   */
+  nsCOMPtr<nsISupports> mItemData;
+};
+
+class EventChainPreVisitor : public EventChainVisitor
+{
+public:
+  EventChainPreVisitor(nsPresContext* aPresContext,
+                       WidgetEvent* aEvent,
+                       nsIDOMEvent* aDOMEvent,
+                       nsEventStatus aEventStatus,
+                       bool aIsInAnon)
+    : EventChainVisitor(aPresContext, aEvent, aDOMEvent, aEventStatus)
+    , mCanHandle(true)
+    , mAutomaticChromeDispatch(true)
+    , mForceContentDispatch(false)
+    , mRelatedTargetIsInAnon(false)
+    , mOriginalTargetIsInAnon(aIsInAnon)
+    , mWantsWillHandleEvent(false)
+    , mMayHaveListenerManager(true)
+    , mParentTarget(nullptr)
+    , mEventTargetAtParent(nullptr)
+  {
+  }
+
+  void Reset()
+  {
+    mItemFlags = 0;
+    mItemData = nullptr;
+    mCanHandle = true;
+    mAutomaticChromeDispatch = true;
+    mForceContentDispatch = false;
+    mWantsWillHandleEvent = false;
+    mMayHaveListenerManager = true;
+    mParentTarget = nullptr;
+    mEventTargetAtParent = nullptr;
+  }
+
+  /**
+   * Member that must be set in PreHandleEvent by event targets. If set to false,
+   * indicates that this event target will not be handling the event and
+   * construction of the event target chain is complete. The target that sets
+   * mCanHandle to false is NOT included in the event target chain.
+   */
+  bool                  mCanHandle;
+
+  /**
+   * If mCanHandle is false and mAutomaticChromeDispatch is also false
+   * event will not be dispatched to the chrome event handler.
+   */
+  bool                  mAutomaticChromeDispatch;
+
+  /**
+   * If mForceContentDispatch is set to true,
+   * content dispatching is not disabled for this event target.
+   * FIXME! This is here for backward compatibility. Bug 329119
+   */
+  bool                  mForceContentDispatch;
+
+  /**
+   * true if it is known that related target is or is a descendant of an
+   * element which is anonymous for events.
+   */
+  bool                  mRelatedTargetIsInAnon;
+
+  /**
+   * true if the original target of the event is inside anonymous content.
+   * This is set before calling PreHandleEvent on event targets.
+   */
+  bool                  mOriginalTargetIsInAnon;
+
+  /**
+   * Whether or not nsIDOMEventTarget::WillHandleEvent will be
+   * called. Default is false;
+   */
+  bool                  mWantsWillHandleEvent;
+
+  /**
+   * If it is known that the current target doesn't have a listener manager
+   * when PreHandleEvent is called, set this to false.
+   */
+  bool                  mMayHaveListenerManager;
+
+  /**
+   * Parent item in the event target chain.
+   */
+  dom::EventTarget* mParentTarget;
+
+  /**
+   * If the event needs to be retargeted, this is the event target,
+   * which should be used when the event is handled at mParentTarget.
+   */
+  dom::EventTarget* mEventTargetAtParent;
+
+  /**
+   * An array of destination insertion points that need to be inserted
+   * into the event path of nodes that are distributed by the
+   * web components distribution algorithm.
+   */
+  nsTArray<nsIContent*> mDestInsertionPoints;
+};
+
+class EventChainPostVisitor : public mozilla::EventChainVisitor
+{
+public:
+  explicit EventChainPostVisitor(EventChainVisitor& aOther)
+    : EventChainVisitor(aOther.mPresContext, aOther.mEvent,
+                        aOther.mDOMEvent, aOther.mEventStatus)
+  {
+  }
+};
+
+/**
+ * If an EventDispatchingCallback object is passed to Dispatch,
+ * its HandleEvent method is called after handling the default event group,
+ * before handling the system event group.
+ * This is used in nsPresShell.
+ */
+class MOZ_STACK_CLASS EventDispatchingCallback
+{
+public:
+  virtual void HandleEvent(EventChainPostVisitor& aVisitor) = 0;
+};
+
+/**
+ * The generic class for event dispatching.
+ * Must not be used outside Gecko!
+ */
+class EventDispatcher
+{
+public:
+  /**
+   * aTarget should QI to EventTarget.
+   * If the target of aEvent is set before calling this method, the target of 
+   * aEvent is used as the target (unless there is event
+   * retargeting) and the originalTarget of the DOM Event.
+   * aTarget is always used as the starting point for constructing the event
+   * target chain, no matter what the value of aEvent->mTarget is.
+   * In other words, aEvent->mTarget is only a property of the event and it has
+   * nothing to do with the construction of the event target chain.
+   * Neither aTarget nor aEvent is allowed to be nullptr.
+   *
+   * If aTargets is non-null, event target chain will be created, but
+   * event won't be handled. In this case aEvent->mMessage should be
+   * eVoidEvent.
+   * @note Use this method when dispatching a WidgetEvent.
+   */
+  static nsresult Dispatch(nsISupports* aTarget,
+                           nsPresContext* aPresContext,
+                           WidgetEvent* aEvent,
+                           nsIDOMEvent* aDOMEvent = nullptr,
+                           nsEventStatus* aEventStatus = nullptr,
+                           EventDispatchingCallback* aCallback = nullptr,
+                           nsTArray<dom::EventTarget*>* aTargets = nullptr);
+
+  /**
+   * Dispatches an event.
+   * If aDOMEvent is not nullptr, it is used for dispatching
+   * (aEvent can then be nullptr) and (if aDOMEvent is not |trusted| already),
+   * the |trusted| flag is set based on the UniversalXPConnect capability.
+   * Otherwise this works like EventDispatcher::Dispatch.
+   * @note Use this method when dispatching nsIDOMEvent.
+   */
+  static nsresult DispatchDOMEvent(nsISupports* aTarget,
+                                   WidgetEvent* aEvent,
+                                   nsIDOMEvent* aDOMEvent,
+                                   nsPresContext* aPresContext,
+                                   nsEventStatus* aEventStatus);
+
+  /**
+   * Creates a DOM Event.  Returns null if the event type is unsupported.
+   */
+  static already_AddRefed<dom::Event> CreateEvent(dom::EventTarget* aOwner,
+                                                  nsPresContext* aPresContext,
+                                                  WidgetEvent* aEvent,
+                                                  const nsAString& aEventType);
+
+  /**
+   * Called at shutting down.
+   */
+  static void Shutdown();
+};
+
+} // namespace mozilla
+
+#endif // mozilla_EventDispatcher_h_
+#endif