InputAPZContext.h - mozsearch

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/* -*- 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_layers_InputAPZContext_h

#define mozilla_layers_InputAPZContext_h

#include "mozilla/EventForwards.h"

#include "mozilla/layers/ScrollableLayerGuid.h"

namespace mozilla {

namespace layers {

// InputAPZContext is used to communicate various pieces of information

// around the codebase without having to plumb it through lots of functions

// and codepaths. Conceptually it is attached to a WidgetInputEvent that is

// relevant to APZ.

//

// There are two types of information bits propagated using this class. One

// type is propagated "downwards" (from a process entry point like nsBaseWidget

// or BrowserChild) into deeper code that is run during complicated operations

// like event dispatch. The other type is information that is propagated

// "upwards", from the deeper code back to the entry point.

class MOZ_STACK_CLASS InputAPZContext {

 private:

  // State that is propagated downwards from InputAPZContext creation into

  // "deeper" code.

  static ScrollableLayerGuid sGuid;

  static uint64_t sBlockId;

  static nsEventStatus sApzResponse;

  static bool sPendingLayerization;

  // State that is set in deeper code and propagated upwards.

  static bool sRoutedToChildProcess;

  // True if the WidgetInputEvent was dropped (which means the event wasn't

  // dispatched) on the main-thread.

  static bool sDropped;

 public:

  // Functions to access downwards-propagated data

  static ScrollableLayerGuid GetTargetLayerGuid();

  static uint64_t GetInputBlockId();

  static nsEventStatus GetApzResponse();

  static bool HavePendingLayerization();

  // Functions to access upwards-propagated data

  static bool WasRoutedToChildProcess();

  static bool WasDropped();

  // Constructor sets the data to be propagated downwards

  InputAPZContext(const ScrollableLayerGuid& aGuid, const uint64_t& aBlockId,

                  const nsEventStatus& aApzResponse,

                  bool aPendingLayerization = false);

  ~InputAPZContext();

  // Functions to set data to be propagated upwards

  static void SetRoutedToChildProcess();

  static void SetDropped();

 private:

  ScrollableLayerGuid mOldGuid;

  uint64_t mOldBlockId;

  nsEventStatus mOldApzResponse;

  bool mOldPendingLayerization;

  bool mOldRoutedToChildProcess;

  bool mOldDropped;

};

}  // namespace layers

}  // namespace mozilla

#endif /* mozilla_layers_InputAPZContext_h */