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 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is mozilla.org code.
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 * The Initial Developer of the Original Code is
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 * Contributor(s):
 *
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#ifndef nsIEventStateManager_h__
#define nsIEventStateManager_h__

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

class nsIContent;
class nsIDocument;
class nsPresContext;
class nsIDOMEvent;
class nsIFrame;
class nsIView;
class nsIWidget;
class imgIContainer;

/*
 * Event state manager interface.
 */
#define NS_IEVENTSTATEMANAGER_IID \
{0x69ab5b16, 0x6690, 0x42fc, \
  { 0xa9, 0xe5, 0xa3, 0xb4, 0xf8, 0x0f, 0xcb, 0xa6 } }

#define NS_EVENT_NEEDS_FRAME(event) (!NS_IS_ACTIVATION_EVENT(event))

class nsIEventStateManager : public nsISupports {

public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IEVENTSTATEMANAGER_IID)

  NS_IMETHOD Init() = 0;

  NS_IMETHOD PreHandleEvent(nsPresContext* aPresContext, 
                            nsEvent *aEvent, 
                            nsIFrame* aTargetFrame,
                            nsEventStatus* aStatus,
                            nsIView* aView) = 0;

  NS_IMETHOD PostHandleEvent(nsPresContext* aPresContext, 
                             nsEvent *aEvent, 
                             nsIFrame* aTargetFrame,
                             nsEventStatus* aStatus,
                             nsIView* aView) = 0;

  NS_IMETHOD SetPresContext(nsPresContext* aPresContext) = 0;
  NS_IMETHOD ClearFrameRefs(nsIFrame* aFrame) = 0;

  NS_IMETHOD GetEventTarget(nsIFrame **aFrame) = 0;
  NS_IMETHOD GetEventTargetContent(nsEvent* aEvent, nsIContent** aContent) = 0;

  /**
   * Returns the content state of aContent.
   * @param aContent      The control whose state is requested.
   * @param aFollowLabels Whether to reflect a label's content state on its
   *                      associated control. If aFollowLabels is true and
   *                      aContent is a control which has a label that has the 
   *                      hover or active content state set, GetContentState
   *                      will pretend that those states are also set on aContent.
   * @return              The content state.
   */
  virtual nsEventStates GetContentState(nsIContent *aContent,
                                        PRBool aFollowLabels = PR_FALSE) = 0;

  /**
   * Notify that the given NS_EVENT_STATE_* bit has changed for this content.
   * @param aContent Content which has changed states.  This may be null to
   *                 indicate that nothing is in this state anymore.
   * @param aState   One of NS_EVENT_STATE_ACTIVE, NS_EVENT_STATE_HOVER,
   *                 NS_EVENT_STATE_DRAGOVER, NS_EVENT_STATE_URLTARGET.  Don't
   *                 pass anything else!  Passing in a state object that has
   *                 more than one of those states set is not supported.
   * @return  Whether the content was able to change all states. Returns PR_FALSE
   *                  if a resulting DOM event causes the content node passed in
   *                  to not change states. Note, the frame for the content may
   *                  change as a result of the content state change, because of
   *                  frame reconstructions that may occur, but this does not
   *                  affect the return value.
   */
  virtual PRBool SetContentState(nsIContent *aContent, nsEventStates aState) = 0;

  NS_IMETHOD ContentRemoved(nsIDocument* aDocument, nsIContent* aContent) = 0;
  NS_IMETHOD EventStatusOK(nsGUIEvent* aEvent, PRBool *aOK) = 0;

  // Access Key Registration

  /**
   * Register accesskey on the given element. When accesskey is activated then
   * the element will be notified via nsIContent::PerformAccesskey() method.
   *
   * @param  aContent  the given element
   * @param  aKey      accesskey
   */
  NS_IMETHOD RegisterAccessKey(nsIContent* aContent, PRUint32 aKey) = 0;

  /**
   * Unregister accesskey for the given element.
   *
   * @param  aContent  the given element
   * @param  aKey      accesskey
   */
  NS_IMETHOD UnregisterAccessKey(nsIContent* aContent, PRUint32 aKey) = 0;

  /**
   * Get accesskey registered on the given element or 0 if there is none.
   *
   * @param  aContent  the given element
   * @param  aKey      registered accesskey
   * @return           NS_OK
   */
  NS_IMETHOD GetRegisteredAccessKey(nsIContent* aContent, PRUint32* aKey) = 0;

  NS_IMETHOD SetCursor(PRInt32 aCursor, imgIContainer* aContainer,
                       PRBool aHaveHotspot, float aHotspotX, float aHotspotY,
                       nsIWidget* aWidget, PRBool aLockCursor) = 0;

  NS_IMETHOD NotifyDestroyPresContext(nsPresContext* aPresContext) = 0;
  
  /**
   * Returns true if the current code is being executed as a result of user input.
   * This includes timers or anything else that is initiated from user input.
   * However, mouse hover events are not counted as user input, nor are
   * page load events. If this method is called from asynchronously executed code,
   * such as during layout reflows, it will return false.
   */
  NS_IMETHOD_(PRBool) IsHandlingUserInputExternal() = 0;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsIEventStateManager, NS_IEVENTSTATEMANAGER_IID)

#endif // nsIEventStateManager_h__
