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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * 1.1 (the "License"); you may not use this file except in compliance with
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 *
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
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 * Contributor(s):
 *
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 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#ifndef nsIEventListenerManager_h__
#define nsIEventListenerManager_h__

#include "nsEvent.h"
#include "nsISupports.h"

class nsPresContext;
class nsIDOMEventListener;
class nsIScriptContext;
class nsIDOMEventTarget;
class nsIDOMEventGroup;
class nsIAtom;
class nsPIDOMEventTarget;

/*
 * Event listener manager interface.
 */
#define NS_IEVENTLISTENERMANAGER_IID \
{ 0xadfdc265, 0xea1c, 0x4c0b, \
  { 0x91, 0xca, 0x37, 0x67, 0x2c, 0x83, 0x92, 0x1f } }

class nsIEventListenerManager : public nsISupports {

public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IEVENTLISTENERMANAGER_IID)

  nsIEventListenerManager() : mMayHavePaintEventListener(PR_FALSE),
    mMayHaveMutationListeners(PR_FALSE),
    mNoListenerForEvent(0)
  {}

  /**
  * Sets events listeners of all types.
  * @param an event listener
  */
  NS_IMETHOD AddEventListenerByIID(nsIDOMEventListener *aListener,
                                   const nsIID& aIID, PRInt32 flags) = 0;

  /**
  * Removes events listeners of all types.
  * @param an event listener
  */
  NS_IMETHOD RemoveEventListenerByIID(nsIDOMEventListener *aListener,
                                      const nsIID& aIID, PRInt32 flags) = 0;

  /**
  * Sets events listeners of all types.
  * @param an event listener
  */
  NS_IMETHOD AddEventListenerByType(nsIDOMEventListener *aListener,
                                    const nsAString& type,
                                    PRInt32 flags,
                                    nsIDOMEventGroup* aEvtGrp) = 0;

  /**
  * Removes events listeners of all types.
  * @param an event listener
  */
  NS_IMETHOD RemoveEventListenerByType(nsIDOMEventListener *aListener,
                                       const nsAString& type,
                                       PRInt32 flags,
                                       nsIDOMEventGroup* aEvtGrp) = 0;

  /**
  * Creates a script event listener for the given script object with
  * name aName and function body aFunc.
  * @param an event listener
  */
  NS_IMETHOD AddScriptEventListener(nsISupports *aObject,
                                    nsIAtom *aName,
                                    const nsAString& aFunc,
                                    PRUint32 aLanguage,
                                    PRBool aDeferCompilation,
                                    PRBool aPermitUntrustedEvents) = 0;


  NS_IMETHOD RemoveScriptEventListener(nsIAtom *aName) = 0;

  /**
  * Registers an event listener that already exists on the given
  * script object with the event listener manager. If the event
  * listener is registerd from chrome code, the event listener will
  * only ever receive trusted events.
  * @param the name of an event listener
  */
  NS_IMETHOD RegisterScriptEventListener(nsIScriptContext *aContext,
                                         void *aScopeObject,
                                         nsISupports *aObject,
                                         nsIAtom* aName) = 0;

  /**
  * Compiles any event listeners that already exists on the given
  * script object for a given event type.
  * @param an event listener */
  NS_IMETHOD CompileScriptEventListener(nsIScriptContext *aContext,
                                        void *aScopeObject,
                                        nsISupports *aObject,
                                        nsIAtom* aName,
                                        PRBool *aDidCompile) = 0;

  /**
  * Causes a check for event listeners and processing by them if they exist.
  * Event flags live in nsGUIEvent.h
  * @param an event listener
  */
  NS_IMETHOD HandleEvent(nsPresContext* aPresContext,
                         nsEvent* aEvent,
                         nsIDOMEvent** aDOMEvent,
                         nsPIDOMEventTarget* aCurrentTarget,
                         PRUint32 aFlags,
                         nsEventStatus* aEventStatus) = 0;

  /**
  * Tells the event listener manager that its target (which owns it) is
  * no longer using it (and could go away).
  *
  * It also clears the weak pointer set by the call to
  * |SetListenerTarget|.
  */
  NS_IMETHOD Disconnect() = 0;

  /**
  * Tells the event listener manager what its target is.  This must be
  * followed by a call to |Disconnect| before the target is destroyed.
  */
  NS_IMETHOD SetListenerTarget(nsISupports* aTarget) = 0;

  /**
  * Allows us to quickly determine if we have mutation listeners registered.
  */
  NS_IMETHOD HasMutationListeners(PRBool* aListener) = 0;

  /**
  * Gets the EventGroup registered for use by system event listeners.
  * This is a special EventGroup which is used in the secondary DOM Event
  * Loop pass for evaluation of system event listeners.
  */
  NS_IMETHOD GetSystemEventGroupLM(nsIDOMEventGroup** aGroup) = 0;

  /**
   * Allows us to quickly determine whether we have unload or beforeunload
   * listeners registered.
   */
  virtual PRBool HasUnloadListeners() = 0;

  /**
   * Returns the mutation bits depending on which mutation listeners are
   * registered to this listener manager.
   * @note If a listener is an nsIDOMMutationListener, all possible mutation
   *       event bits are returned. All bits are also returned if one of the
   *       event listeners is registered to handle DOMSubtreeModified events.
   */
  virtual PRUint32 MutationListenerBits() = 0;

  /**
   * Returns PR_TRUE if there is at least one event listener for aEventName.
   */
  virtual PRBool HasListenersFor(const nsAString& aEventName) = 0;

  /**
   * Returns PR_TRUE if there is at least one event listener.
   */
  virtual PRBool HasListeners() = 0;


  /**
   * Returns PR_TRUE if there may be a paint event listener registered,
   * PR_FALSE if there definitely isn't.
   */
  PRBool MayHavePaintEventListener() { return mMayHavePaintEventListener; }

protected:
  PRUint32 mMayHavePaintEventListener : 1;
  PRUint32 mMayHaveMutationListeners : 1;
  // These two member variables are used to cache the information
  // about the last event which was handled but for which event listener manager
  // didn't have event listeners.
  PRUint32 mNoListenerForEvent : 30;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsIEventListenerManager,
                              NS_IEVENTLISTENERMANAGER_IID)

nsresult
NS_NewEventListenerManager(nsIEventListenerManager** aInstancePtrResult);

#endif // nsIEventListenerManager_h__
