/* -*- 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_PendingAnimationTracker_h

#define mozilla_dom_PendingAnimationTracker_h

#include "mozilla/dom/Animation.h"

#include "nsCycleCollectionParticipant.h"

#include "nsIDocument.h"

#include "nsTHashtable.h"

class nsIFrame;

namespace mozilla {

class PendingAnimationTracker final

{

public:

  explicit PendingAnimationTracker(nsIDocument* aDocument)

    : mDocument(aDocument)

  { }

  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(PendingAnimationTracker)

  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(PendingAnimationTracker)

  void AddPlayPending(dom::Animation& aAnimation)

  {

    // We'd like to assert here that IsWaitingToPause(aAnimation) is false but

    // if |aAnimation| was tracked here as a pause-pending animation when it was

    // removed from |mDocument|, then re-attached to |mDocument|, and then

    // played again, we could end up here with IsWaitingToPause returning true.

    //

    // However, that should be harmless since all it means is that we'll call

    // Animation::TriggerOnNextTick or Animation::TriggerNow twice, both of

    // which will handle the redundant call gracefully.

    AddPending(aAnimation, mPlayPendingSet);

    mHasPlayPendingGeometricAnimations = CheckState::Indeterminate;

  }

  void RemovePlayPending(dom::Animation& aAnimation)

  {

    RemovePending(aAnimation, mPlayPendingSet);

    mHasPlayPendingGeometricAnimations = CheckState::Indeterminate;

  }

  bool IsWaitingToPlay(const dom::Animation& aAnimation) const

  {

    return IsWaiting(aAnimation, mPlayPendingSet);

  }

  void AddPausePending(dom::Animation& aAnimation)

  {

    // As with AddPausePending, we'd like to assert that

    // IsWaitingToPlay(aAnimation) is false but there are some circumstances

    // where this can be true. Fortunately adding the animation to both pending

    // sets should be harmless.

    AddPending(aAnimation, mPausePendingSet);

  }

  void RemovePausePending(dom::Animation& aAnimation)

  {

    RemovePending(aAnimation, mPausePendingSet);

  }

  bool IsWaitingToPause(const dom::Animation& aAnimation) const

  {

    return IsWaiting(aAnimation, mPausePendingSet);

  }

  void TriggerPendingAnimationsOnNextTick(const TimeStamp& aReadyTime);

  void TriggerPendingAnimationsNow();

  bool HasPendingAnimations() const {

    return mPlayPendingSet.Count() > 0 || mPausePendingSet.Count() > 0;

  }

  /**

   * Looks amongst the set of play-pending animations, and, if there are

   * animations that affect geometric properties, notifies all play-pending

   * animations so that they can be synchronized, if needed.

   */

  void MarkAnimationsThatMightNeedSynchronization();

private:

  ~PendingAnimationTracker() { }

  bool HasPlayPendingGeometricAnimations();

  void EnsurePaintIsScheduled();

  typedef nsTHashtable<nsRefPtrHashKey<dom::Animation>> AnimationSet;

  void AddPending(dom::Animation& aAnimation, AnimationSet& aSet);

  void RemovePending(dom::Animation& aAnimation, AnimationSet& aSet);

  bool IsWaiting(const dom::Animation& aAnimation,

                 const AnimationSet& aSet) const;

  AnimationSet mPlayPendingSet;

  AnimationSet mPausePendingSet;

  nsCOMPtr<nsIDocument> mDocument;

  enum class CheckState {

    Indeterminate,

    Absent,

    Present

  };

  CheckState mHasPlayPendingGeometricAnimations = CheckState::Indeterminate;

};

} // namespace mozilla

#endif // mozilla_dom_PendingAnimationTracker_h