dom/animation/AnimationTimeline.h
author Tim Huang <tihuang@mozilla.com>
Thu, 31 Aug 2017 11:14:14 +0800
changeset 453921 b2f55468b241f28678dc5e35e19eb3b5781a1c5c
parent 344503 c62fb7ec8761aca772df9cc5e709e1b2ffd57549
child 482472 8beb2cbc6b2538a51f5bbc8f91fee17091fa93ba
permissions -rw-r--r--
Bug 1222285 - Part 2: Making the keyboard events of modifier keys been suppressed when 'privacy.resistFingerprinting' is true. r=arthuredelstein,masayuki This patch makes 'Shift', 'Alt', 'Contorl' and 'AltGraph' been suppressed for content when fingerprinting resistance is enabled. Chrome can still get these events. The reason behind this is that websites can still observe key combinations to tell which keyboard layout is using even we spoof the keyboardEvent.code, keyboardEvent.keyCode and modifier states. For example, the AZERTY France keyboard, the digit keys of it requires the user press the Shift key. So, it is easy to differentiate AZERTY and QWERTY keyboard by observing whether a Shift key generates its own before the digit keys. There are similar issues for 'Alt' and 'AltGraph' as well. MozReview-Commit-ID: 3CwCgvey4lK

/* -*- 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_dom_AnimationTimeline_h
#define mozilla_dom_AnimationTimeline_h

#include "nsISupports.h"
#include "nsWrapperCache.h"
#include "nsCycleCollectionParticipant.h"
#include "js/TypeDecls.h"
#include "mozilla/AnimationUtils.h"
#include "mozilla/Attributes.h"
#include "nsHashKeys.h"
#include "nsIGlobalObject.h"
#include "nsTHashtable.h"

// GetCurrentTime is defined in winbase.h as zero argument macro forwarding to
// GetTickCount().
#ifdef GetCurrentTime
#undef GetCurrentTime
#endif

namespace mozilla {
namespace dom {

class Animation;

class AnimationTimeline
  : public nsISupports
  , public nsWrapperCache
{
public:
  explicit AnimationTimeline(nsIGlobalObject* aWindow)
    : mWindow(aWindow)
  {
    MOZ_ASSERT(mWindow);
  }

protected:
  virtual ~AnimationTimeline()
  {
    mAnimationOrder.clear();
  }

public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(AnimationTimeline)

  nsIGlobalObject* GetParentObject() const { return mWindow; }

  // AnimationTimeline methods
  virtual Nullable<TimeDuration> GetCurrentTime() const = 0;

  // Wrapper functions for AnimationTimeline DOM methods when called from
  // script.
  Nullable<double> GetCurrentTimeAsDouble() const {
    return AnimationUtils::TimeDurationToDouble(GetCurrentTime());
  }

  /**
   * Returns true if the times returned by GetCurrentTime() are convertible
   * to and from wallclock-based TimeStamp (e.g. from TimeStamp::Now()) values
   * using ToTimelineTime() and ToTimeStamp().
   *
   * Typically this is true, but it will be false in the case when this
   * timeline has no refresh driver or is tied to a refresh driver under test
   * control.
   */
  virtual bool TracksWallclockTime() const = 0;

  /**
   * Converts a TimeStamp to the equivalent value in timeline time.
   * Note that when TracksWallclockTime() is false, there is no correspondence
   * between timeline time and wallclock time. In such a case, passing a
   * timestamp from TimeStamp::Now() to this method will not return a
   * meaningful result.
   */
  virtual Nullable<TimeDuration> ToTimelineTime(const TimeStamp&
                                                  aTimeStamp) const = 0;

  virtual TimeStamp ToTimeStamp(const TimeDuration& aTimelineTime) const = 0;

  /**
   * Inform this timeline that |aAnimation| which is or was observing the
   * timeline, has been updated. This serves as both the means to associate
   * AND disassociate animations with a timeline. The timeline itself will
   * determine if it needs to begin, continue or stop tracking this animation.
   */
  virtual void NotifyAnimationUpdated(Animation& aAnimation);

  /**
   * Returns true if any CSS animations, CSS transitions or Web animations are
   * currently associated with this timeline.  As soon as an animation is
   * applied to an element it is associated with the timeline even if it has a
   * delayed start, so this includes animations that may not be active for some
   * time.
   */
  bool HasAnimations() const {
    return !mAnimations.IsEmpty();
  }

  virtual void RemoveAnimation(Animation* aAnimation);

protected:
  nsCOMPtr<nsIGlobalObject> mWindow;

  // Animations observing this timeline
  //
  // We store them in (a) a hashset for quick lookup, and (b) an array
  // to maintain a fixed sampling order.
  //
  // The hashset keeps a strong reference to each animation since
  // dealing with addref/release with LinkedList is difficult.
  typedef nsTHashtable<nsRefPtrHashKey<dom::Animation>> AnimationSet;
  AnimationSet mAnimations;
  LinkedList<dom::Animation> mAnimationOrder;
};

} // namespace dom
} // namespace mozilla

#endif // mozilla_dom_AnimationTimeline_h