tenfourfox/gfx/layers/apz/util/ActiveElementManager.h
Cameron Kaiser c9b2922b70 hello FPR
2017-04-19 00:56:45 -07:00

104 lines
3.0 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_layers_ActiveElementManager_h
#define mozilla_layers_ActiveElementManager_h
#include "nsCOMPtr.h"
#include "nsISupportsImpl.h"
class CancelableTask;
namespace mozilla {
namespace dom {
class Element;
class EventTarget;
} // namespace dom
namespace layers {
/**
* Manages setting and clearing the ':active' CSS pseudostate in the presence
* of touch input.
*/
class ActiveElementManager {
~ActiveElementManager();
public:
NS_INLINE_DECL_REFCOUNTING(ActiveElementManager)
ActiveElementManager();
/**
* Specify the target of a touch. Typically this should be called right
* after HandleTouchStart(), but in cases where the APZ needs to wait for
* a content response the HandleTouchStart() may be delayed, in which case
* this function can be called first.
* |aTarget| may be nullptr.
*/
void SetTargetElement(dom::EventTarget* aTarget);
/**
* Handle a touch-start state notification from APZ. This notification
* may be delayed until after touch listeners have responded to the APZ.
* @param aCanBePan whether the touch can be a pan
*/
void HandleTouchStart(bool aCanBePan);
/**
* Clear the active element.
*/
void ClearActivation();
/**
* Handle a touch-end or touch-cancel event.
* @param aWasClick whether the touch was a click
*/
void HandleTouchEndEvent(bool aWasClick);
/**
* Handle a touch-end state notification from APZ. This notification may be
* delayed until after touch listeners have responded to the APZ.
*/
void HandleTouchEnd();
/**
* @return true iff the currently active element (or one of its ancestors)
* actually had a style for the :active pseudo-class. The currently active
* element is the root element if no other elements are active.
*/
bool ActiveElementUsesStyle() const;
private:
/**
* The target of the first touch point in the current touch block.
*/
nsCOMPtr<dom::Element> mTarget;
/**
* Whether the current touch block can be a pan. Set in HandleTouchStart().
*/
bool mCanBePan;
/**
* Whether mCanBePan has been set for the current touch block.
* We need to keep track of this to allow HandleTouchStart() and
* SetTargetElement() to be called in either order.
*/
bool mCanBePanSet;
/**
* A task for calling SetActive() after a timeout.
*/
CancelableTask* mSetActiveTask;
/**
* See ActiveElementUsesStyle() documentation.
*/
bool mActiveElementUsesStyle;
// Helpers
void TriggerElementActivation();
void SetActive(dom::Element* aTarget);
void ResetActive();
void ResetTouchBlockState();
void SetActiveTask(dom::Element* aTarget);
void CancelTask();
};
} // namespace layers
} // namespace mozilla
#endif /* mozilla_layers_ActiveElementManager_h */