ui/compositor/layer

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This source file includes following definitions.
GetAnimationContainer
adding_animations_
CreateDefaultAnimator
CreateImplicitAnimator
GetTransitionDuration
SetDelegate
StartAnimation
ScheduleAnimation
StartTogether
ScheduleTogether
SchedulePauseForProperties
IsAnimatingProperty
StopAnimatingProperty
AddObserver
RemoveObserver
OnThreadedAnimationStarted
ProgressAnimation
ProgressAnimationToEnd
HasAnimation
Step
SetStartTime
GetTimerInterval
StopAnimatingInternal
UpdateAnimationState
RemoveAnimation
FinishAnimation
FinishAnyAnimationWithZeroDuration
ClearAnimations
GetRunningAnimation
AddToQueueIfNotPresent
RemoveAllAnimationsWithACommonProperty
ImmediatelySetNewTarget
ImmediatelyAnimateToNewTarget
EnqueueNewAnimation
ReplaceQueuedAnimations
ProcessQueue
StartSequenceImmediately
GetTargetValue
OnScheduled
SetTransitionDuration
ClearAnimationsInternal
PurgeDeletedAnimations
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/compositor/layer_animator.h"

#include "base/debug/trace_event.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "cc/animation/animation_id_provider.h"
#include "cc/output/begin_frame_args.h"
#include "ui/compositor/compositor.h"
#include "ui/compositor/layer.h"
#include "ui/compositor/layer_animation_delegate.h"
#include "ui/compositor/layer_animation_observer.h"
#include "ui/compositor/layer_animation_sequence.h"
#include "ui/gfx/animation/animation_container.h"
#include "ui/gfx/frame_time.h"

#define SAFE_INVOKE_VOID(function, running_anim, ...) \
    if (running_anim.is_sequence_alive()) \
      function(running_anim.sequence(), ##__VA_ARGS__)
#define SAFE_INVOKE_BOOL(function, running_anim) \
    ((running_anim.is_sequence_alive()) \
        ? function(running_anim.sequence()) \
        : false)
#define SAFE_INVOKE_PTR(function, running_anim) \
    ((running_anim.is_sequence_alive()) \
        ? function(running_anim.sequence()) \
        : NULL)

namespace ui {

class LayerAnimator;

namespace {

const int kDefaultTransitionDurationMs = 120;
const int kTimerIntervalMs = 10;

// Returns the AnimationContainer we're added to.
gfx::AnimationContainer* GetAnimationContainer() {
  static gfx::AnimationContainer* container = NULL;
  if (!container) {
    container = new gfx::AnimationContainer();
    container->AddRef();
  }
  return container;
}

}  // namespace

// LayerAnimator public --------------------------------------------------------

LayerAnimator::LayerAnimator(base::TimeDelta transition_duration)
    : delegate_(NULL),
      preemption_strategy_(IMMEDIATELY_SET_NEW_TARGET),
      is_transition_duration_locked_(false),
      transition_duration_(transition_duration),
      tween_type_(gfx::Tween::LINEAR),
      is_started_(false),
      disable_timer_for_test_(false),
      adding_animations_(false) {
}

LayerAnimator::~LayerAnimator() {
  for (size_t i = 0; i < running_animations_.size(); ++i) {
    if (running_animations_[i].is_sequence_alive())
      running_animations_[i].sequence()->OnAnimatorDestroyed();
  }
  ClearAnimationsInternal();
  delegate_ = NULL;
}

// static
LayerAnimator* LayerAnimator::CreateDefaultAnimator() {
  return new LayerAnimator(base::TimeDelta::FromMilliseconds(0));
}

// static
LayerAnimator* LayerAnimator::CreateImplicitAnimator() {
  return new LayerAnimator(
      base::TimeDelta::FromMilliseconds(kDefaultTransitionDurationMs));
}

// This macro provides the implementation for the setter and getter (well,
// the getter of the target value) for an animated property. For example,
// it is used for the implementations of SetTransform and GetTargetTransform.
// It is worth noting that SetFoo avoids invoking the usual animation machinery
// if the transition duration is zero -- in this case we just set the property
// on the layer animation delegate immediately.
#define ANIMATED_PROPERTY(type, property, name, member_type, member)  \
void LayerAnimator::Set##name(type value) {                           \
  base::TimeDelta duration = GetTransitionDuration();                 \
  if (duration == base::TimeDelta() && delegate() &&                  \
      (preemption_strategy_ != ENQUEUE_NEW_ANIMATION)) {              \
    StopAnimatingProperty(LayerAnimationElement::property);           \
    delegate()->Set##name##FromAnimation(value);                      \
    return;                                                           \
  }                                                                   \
  scoped_ptr<LayerAnimationElement> element(                          \
      LayerAnimationElement::Create##name##Element(value, duration)); \
  element->set_tween_type(tween_type_);                               \
  StartAnimation(new LayerAnimationSequence(element.release()));      \
}                                                                     \
                                                                      \
member_type LayerAnimator::GetTarget##name() const {                  \
  LayerAnimationElement::TargetValue target(delegate());              \
  GetTargetValue(&target);                                            \
  return target.member;                                               \
}

ANIMATED_PROPERTY(
    const gfx::Transform&, TRANSFORM, Transform, gfx::Transform, transform);
ANIMATED_PROPERTY(const gfx::Rect&, BOUNDS, Bounds, gfx::Rect, bounds);
ANIMATED_PROPERTY(float, OPACITY, Opacity, float, opacity);
ANIMATED_PROPERTY(bool, VISIBILITY, Visibility, bool, visibility);
ANIMATED_PROPERTY(float, BRIGHTNESS, Brightness, float, brightness);
ANIMATED_PROPERTY(float, GRAYSCALE, Grayscale, float, grayscale);
ANIMATED_PROPERTY(SkColor, COLOR, Color, SkColor, color);

base::TimeDelta LayerAnimator::GetTransitionDuration() const {
  return transition_duration_;
}

void LayerAnimator::SetDelegate(LayerAnimationDelegate* delegate) {
  delegate_ = delegate;
}

void LayerAnimator::StartAnimation(LayerAnimationSequence* animation) {
  scoped_refptr<LayerAnimator> retain(this);
  OnScheduled(animation);
  if (!StartSequenceImmediately(animation)) {
    // Attempt to preempt a running animation.
    switch (preemption_strategy_) {
      case IMMEDIATELY_SET_NEW_TARGET:
        ImmediatelySetNewTarget(animation);
        break;
      case IMMEDIATELY_ANIMATE_TO_NEW_TARGET:
        ImmediatelyAnimateToNewTarget(animation);
        break;
      case ENQUEUE_NEW_ANIMATION:
        EnqueueNewAnimation(animation);
        break;
      case REPLACE_QUEUED_ANIMATIONS:
        ReplaceQueuedAnimations(animation);
        break;
      case BLEND_WITH_CURRENT_ANIMATION: {
        // TODO(vollick) Add support for blended sequences and use them here.
        NOTIMPLEMENTED();
        break;
      }
    }
  }
  FinishAnyAnimationWithZeroDuration();
  UpdateAnimationState();
}

void LayerAnimator::ScheduleAnimation(LayerAnimationSequence* animation) {
  scoped_refptr<LayerAnimator> retain(this);
  OnScheduled(animation);
  if (is_animating()) {
    animation_queue_.push_back(make_linked_ptr(animation));
    ProcessQueue();
  } else {
    StartSequenceImmediately(animation);
  }
  UpdateAnimationState();
}

void LayerAnimator::StartTogether(
    const std::vector<LayerAnimationSequence*>& animations) {
  scoped_refptr<LayerAnimator> retain(this);
  if (preemption_strategy_ == IMMEDIATELY_SET_NEW_TARGET) {
    std::vector<LayerAnimationSequence*>::const_iterator iter;
    for (iter = animations.begin(); iter != animations.end(); ++iter) {
      StartAnimation(*iter);
    }
    return;
  }

  adding_animations_ = true;
  if (!is_animating()) {
    if (GetAnimationContainer()->is_running())
      last_step_time_ = GetAnimationContainer()->last_tick_time();
    else
      last_step_time_ = gfx::FrameTime::Now();
  }

  // Collect all the affected properties.
  LayerAnimationElement::AnimatableProperties animated_properties =
      LayerAnimationElement::UNKNOWN;

  std::vector<LayerAnimationSequence*>::const_iterator iter;
  for (iter = animations.begin(); iter != animations.end(); ++iter)
    animated_properties |= (*iter)->properties();

  // Starting a zero duration pause that affects all the animated properties
  // will prevent any of the sequences from animating until there are no
  // running animations that affect any of these properties, as well as
  // handle preemption strategy.
  StartAnimation(new LayerAnimationSequence(
      LayerAnimationElement::CreatePauseElement(animated_properties,
                                                base::TimeDelta())));

  bool wait_for_group_start = false;
  for (iter = animations.begin(); iter != animations.end(); ++iter)
    wait_for_group_start |= (*iter)->IsFirstElementThreaded();

  int group_id = cc::AnimationIdProvider::NextGroupId();

  // These animations (provided they don't animate any common properties) will
  // now animate together if trivially scheduled.
  for (iter = animations.begin(); iter != animations.end(); ++iter) {
    (*iter)->set_animation_group_id(group_id);
    (*iter)->set_waiting_for_group_start(wait_for_group_start);
    ScheduleAnimation(*iter);
  }

  adding_animations_ = false;
  UpdateAnimationState();
}


void LayerAnimator::ScheduleTogether(
    const std::vector<LayerAnimationSequence*>& animations) {
  scoped_refptr<LayerAnimator> retain(this);

  // Collect all the affected properties.
  LayerAnimationElement::AnimatableProperties animated_properties =
      LayerAnimationElement::UNKNOWN;

  std::vector<LayerAnimationSequence*>::const_iterator iter;
  for (iter = animations.begin(); iter != animations.end(); ++iter)
    animated_properties |= (*iter)->properties();

  // Scheduling a zero duration pause that affects all the animated properties
  // will prevent any of the sequences from animating until there are no
  // running animations that affect any of these properties.
  ScheduleAnimation(new LayerAnimationSequence(
      LayerAnimationElement::CreatePauseElement(animated_properties,
                                                base::TimeDelta())));

  bool wait_for_group_start = false;
  for (iter = animations.begin(); iter != animations.end(); ++iter)
    wait_for_group_start |= (*iter)->IsFirstElementThreaded();

  int group_id = cc::AnimationIdProvider::NextGroupId();

  // These animations (provided they don't animate any common properties) will
  // now animate together if trivially scheduled.
  for (iter = animations.begin(); iter != animations.end(); ++iter) {
    (*iter)->set_animation_group_id(group_id);
    (*iter)->set_waiting_for_group_start(wait_for_group_start);
    ScheduleAnimation(*iter);
  }

  UpdateAnimationState();
}

void LayerAnimator::SchedulePauseForProperties(
    base::TimeDelta duration,
    LayerAnimationElement::AnimatableProperties properties_to_pause) {
  ScheduleAnimation(new ui::LayerAnimationSequence(
                        ui::LayerAnimationElement::CreatePauseElement(
                            properties_to_pause, duration)));
}

bool LayerAnimator::IsAnimatingProperty(
    LayerAnimationElement::AnimatableProperty property) const {
  for (AnimationQueue::const_iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    if ((*queue_iter)->properties() & property)
      return true;
  }
  return false;
}

void LayerAnimator::StopAnimatingProperty(
    LayerAnimationElement::AnimatableProperty property) {
  scoped_refptr<LayerAnimator> retain(this);
  while (true) {
    // GetRunningAnimation purges deleted animations before searching, so we are
    // guaranteed to find a live animation if any is returned at all.
    RunningAnimation* running = GetRunningAnimation(property);
    if (!running)
      break;
    // As was mentioned above, this sequence must be alive.
    DCHECK(running->is_sequence_alive());
    FinishAnimation(running->sequence(), false);
  }
}

void LayerAnimator::AddObserver(LayerAnimationObserver* observer) {
  if (!observers_.HasObserver(observer))
    observers_.AddObserver(observer);
}

void LayerAnimator::RemoveObserver(LayerAnimationObserver* observer) {
  observers_.RemoveObserver(observer);
  // Remove the observer from all sequences as well.
  for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    (*queue_iter)->RemoveObserver(observer);
  }
}

void LayerAnimator::OnThreadedAnimationStarted(
    const cc::AnimationEvent& event) {
  LayerAnimationElement::AnimatableProperty property =
    LayerAnimationElement::ToAnimatableProperty(event.target_property);

  RunningAnimation* running = GetRunningAnimation(property);
  if (!running)
    return;
  DCHECK(running->is_sequence_alive());

  if (running->sequence()->animation_group_id() != event.group_id)
    return;

  running->sequence()->OnThreadedAnimationStarted(event);
  if (!running->sequence()->waiting_for_group_start())
    return;

  base::TimeTicks start_time = base::TimeTicks::FromInternalValue(
      event.monotonic_time * base::Time::kMicrosecondsPerSecond);

  running->sequence()->set_waiting_for_group_start(false);

  // The call to GetRunningAnimation made above already purged deleted
  // animations, so we are guaranteed that all the animations we iterate
  // over now are alive.
  for (RunningAnimations::iterator iter = running_animations_.begin();
       iter != running_animations_.end(); ++iter) {
    // Ensure that each sequence is only Started once, regardless of the
    // number of sequences in the group that have threaded first elements.
    if (((*iter).sequence()->animation_group_id() == event.group_id) &&
        !(*iter).sequence()->IsFirstElementThreaded() &&
        (*iter).sequence()->waiting_for_group_start()) {
      (*iter).sequence()->set_start_time(start_time);
      (*iter).sequence()->set_waiting_for_group_start(false);
      (*iter).sequence()->Start(delegate());
    }
  }
}

// LayerAnimator protected -----------------------------------------------------

void LayerAnimator::ProgressAnimation(LayerAnimationSequence* sequence,
                                      base::TimeTicks now) {
  if (!delegate() || sequence->waiting_for_group_start())
    return;

  sequence->Progress(now, delegate());
}

void LayerAnimator::ProgressAnimationToEnd(LayerAnimationSequence* sequence) {
  if (!delegate())
    return;

  sequence->ProgressToEnd(delegate());
}

bool LayerAnimator::HasAnimation(LayerAnimationSequence* sequence) const {
  for (AnimationQueue::const_iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    if ((*queue_iter).get() == sequence)
      return true;
  }
  return false;
}

// LayerAnimator private -------------------------------------------------------

void LayerAnimator::Step(base::TimeTicks now) {
  TRACE_EVENT0("ui", "LayerAnimator::Step");
  scoped_refptr<LayerAnimator> retain(this);

  last_step_time_ = now;

  PurgeDeletedAnimations();

  // We need to make a copy of the running animations because progressing them
  // and finishing them may indirectly affect the collection of running
  // animations.
  RunningAnimations running_animations_copy = running_animations_;
  for (size_t i = 0; i < running_animations_copy.size(); ++i) {
    if (!SAFE_INVOKE_BOOL(HasAnimation, running_animations_copy[i]))
      continue;

    if (running_animations_copy[i].sequence()->IsFinished(now)) {
      SAFE_INVOKE_VOID(FinishAnimation, running_animations_copy[i], false);
    } else {
      SAFE_INVOKE_VOID(ProgressAnimation, running_animations_copy[i], now);
    }
  }
}

void LayerAnimator::SetStartTime(base::TimeTicks start_time) {
  // Do nothing.
}

base::TimeDelta LayerAnimator::GetTimerInterval() const {
  return base::TimeDelta::FromMilliseconds(kTimerIntervalMs);
}

void LayerAnimator::StopAnimatingInternal(bool abort) {
  scoped_refptr<LayerAnimator> retain(this);
  while (is_animating()) {
    // We're going to attempt to finish the first running animation. Let's
    // ensure that it's valid.
    PurgeDeletedAnimations();

    // If we've purged all running animations, attempt to start one up.
    if (running_animations_.empty())
      ProcessQueue();

    DCHECK(!running_animations_.empty());

    // Still no luck, let's just bail and clear all animations.
    if (running_animations_.empty()) {
      ClearAnimationsInternal();
      break;
    }

    SAFE_INVOKE_VOID(FinishAnimation, running_animations_[0], abort);
  }
}

void LayerAnimator::UpdateAnimationState() {
  if (disable_timer_for_test_)
    return;

  const bool should_start = is_animating();
  if (should_start && !is_started_)
    GetAnimationContainer()->Start(this);
  else if (!should_start && is_started_)
    GetAnimationContainer()->Stop(this);

  is_started_ = should_start;
}

LayerAnimationSequence* LayerAnimator::RemoveAnimation(
    LayerAnimationSequence* sequence) {
  linked_ptr<LayerAnimationSequence> to_return;

  bool is_running = false;

  // First remove from running animations
  for (RunningAnimations::iterator iter = running_animations_.begin();
       iter != running_animations_.end(); ++iter) {
    if ((*iter).sequence() == sequence) {
      running_animations_.erase(iter);
      is_running = true;
      break;
    }
  }

  // Then remove from the queue
  for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    if ((*queue_iter) == sequence) {
      to_return = *queue_iter;
      animation_queue_.erase(queue_iter);
      break;
    }
  }

  if (!to_return.get() ||
      !to_return->waiting_for_group_start() ||
      !to_return->IsFirstElementThreaded())
    return to_return.release();

  // The removed sequence may have been responsible for making other sequences
  // wait for a group start. If no other sequences in the group have a
  // threaded first element, the group no longer needs the additional wait.
  bool is_wait_still_needed = false;
  int group_id = to_return->animation_group_id();
  for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    if (((*queue_iter)->animation_group_id() == group_id) &&
        (*queue_iter)->IsFirstElementThreaded()) {
      is_wait_still_needed = true;
      break;
    }
  }

  if (is_wait_still_needed)
    return to_return.release();

  for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    if ((*queue_iter)->animation_group_id() == group_id &&
        (*queue_iter)->waiting_for_group_start()) {
      (*queue_iter)->set_waiting_for_group_start(false);
      if (is_running) {
        (*queue_iter)->set_start_time(last_step_time_);
        (*queue_iter)->Start(delegate());
      }
    }
  }
  return to_return.release();
}

void LayerAnimator::FinishAnimation(
    LayerAnimationSequence* sequence, bool abort) {
  scoped_refptr<LayerAnimator> retain(this);
  scoped_ptr<LayerAnimationSequence> removed(RemoveAnimation(sequence));
  if (abort)
    sequence->Abort(delegate());
  else
    ProgressAnimationToEnd(sequence);
  ProcessQueue();
  UpdateAnimationState();
}

void LayerAnimator::FinishAnyAnimationWithZeroDuration() {
  scoped_refptr<LayerAnimator> retain(this);
  // Special case: if we've started a 0 duration animation, just finish it now
  // and get rid of it. We need to make a copy because Progress may indirectly
  // cause new animations to start running.
  RunningAnimations running_animations_copy = running_animations_;
  for (size_t i = 0; i < running_animations_copy.size(); ++i) {
    if (!SAFE_INVOKE_BOOL(HasAnimation, running_animations_copy[i]))
      continue;

    if (running_animations_copy[i].sequence()->IsFinished(
          running_animations_copy[i].sequence()->start_time())) {
      SAFE_INVOKE_VOID(ProgressAnimationToEnd, running_animations_copy[i]);
      scoped_ptr<LayerAnimationSequence> removed(
          SAFE_INVOKE_PTR(RemoveAnimation, running_animations_copy[i]));
    }
  }
  ProcessQueue();
  UpdateAnimationState();
}

void LayerAnimator::ClearAnimations() {
  scoped_refptr<LayerAnimator> retain(this);
  ClearAnimationsInternal();
}

LayerAnimator::RunningAnimation* LayerAnimator::GetRunningAnimation(
    LayerAnimationElement::AnimatableProperty property) {
  PurgeDeletedAnimations();
  for (RunningAnimations::iterator iter = running_animations_.begin();
       iter != running_animations_.end(); ++iter) {
    if ((*iter).sequence()->properties() & property)
      return &(*iter);
  }
  return NULL;
}

void LayerAnimator::AddToQueueIfNotPresent(LayerAnimationSequence* animation) {
  // If we don't have the animation in the queue yet, add it.
  bool found_sequence = false;
  for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter) {
    if ((*queue_iter) == animation) {
      found_sequence = true;
      break;
    }
  }

  if (!found_sequence)
    animation_queue_.push_front(make_linked_ptr(animation));
}

void LayerAnimator::RemoveAllAnimationsWithACommonProperty(
    LayerAnimationSequence* sequence, bool abort) {
  // For all the running animations, if they animate the same property,
  // progress them to the end and remove them. Note, Aborting or Progressing
  // animations may affect the collection of running animations, so we need to
  // operate on a copy.
  RunningAnimations running_animations_copy = running_animations_;
  for (size_t i = 0; i < running_animations_copy.size(); ++i) {
    if (!SAFE_INVOKE_BOOL(HasAnimation, running_animations_copy[i]))
      continue;

    if (running_animations_copy[i].sequence()->HasConflictingProperty(
            sequence->properties())) {
      scoped_ptr<LayerAnimationSequence> removed(
          SAFE_INVOKE_PTR(RemoveAnimation, running_animations_copy[i]));
      if (abort)
        running_animations_copy[i].sequence()->Abort(delegate());
      else
        SAFE_INVOKE_VOID(ProgressAnimationToEnd, running_animations_copy[i]);
    }
  }

  // Same for the queued animations that haven't been started. Again, we'll
  // need to operate on a copy.
  std::vector<base::WeakPtr<LayerAnimationSequence> > sequences;
  for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
       queue_iter != animation_queue_.end(); ++queue_iter)
    sequences.push_back((*queue_iter)->AsWeakPtr());

  for (size_t i = 0; i < sequences.size(); ++i) {
    if (!sequences[i].get() || !HasAnimation(sequences[i].get()))
      continue;

    if (sequences[i]->HasConflictingProperty(sequence->properties())) {
      scoped_ptr<LayerAnimationSequence> removed(
          RemoveAnimation(sequences[i].get()));
      if (abort)
        sequences[i]->Abort(delegate());
      else
        ProgressAnimationToEnd(sequences[i].get());
    }
  }
}

void LayerAnimator::ImmediatelySetNewTarget(LayerAnimationSequence* sequence) {
  // Need to detect if our sequence gets destroyed.
  base::WeakPtr<LayerAnimationSequence> weak_sequence_ptr =
      sequence->AsWeakPtr();

  const bool abort = false;
  RemoveAllAnimationsWithACommonProperty(sequence, abort);
  if (!weak_sequence_ptr.get())
    return;

  LayerAnimationSequence* removed = RemoveAnimation(sequence);
  DCHECK(removed == NULL || removed == sequence);
  if (!weak_sequence_ptr.get())
    return;

  ProgressAnimationToEnd(sequence);
  if (!weak_sequence_ptr.get())
    return;

  delete sequence;
}

void LayerAnimator::ImmediatelyAnimateToNewTarget(
    LayerAnimationSequence* sequence) {
  // Need to detect if our sequence gets destroyed.
  base::WeakPtr<LayerAnimationSequence> weak_sequence_ptr =
      sequence->AsWeakPtr();

  const bool abort = true;
  RemoveAllAnimationsWithACommonProperty(sequence, abort);
  if (!weak_sequence_ptr.get())
    return;

  AddToQueueIfNotPresent(sequence);
  if (!weak_sequence_ptr.get())
    return;

  StartSequenceImmediately(sequence);
}

void LayerAnimator::EnqueueNewAnimation(LayerAnimationSequence* sequence) {
  // It is assumed that if there was no conflicting animation, we would
  // not have been called. No need to check for a collision; just
  // add to the queue.
  animation_queue_.push_back(make_linked_ptr(sequence));
  ProcessQueue();
}

void LayerAnimator::ReplaceQueuedAnimations(LayerAnimationSequence* sequence) {
  // Need to detect if our sequence gets destroyed.
  base::WeakPtr<LayerAnimationSequence> weak_sequence_ptr =
      sequence->AsWeakPtr();

  // Remove all animations that aren't running. Note: at each iteration i is
  // incremented or an element is removed from the queue, so
  // animation_queue_.size() - i is always decreasing and we are always making
  // progress towards the loop terminating.
  for (size_t i = 0; i < animation_queue_.size();) {
    if (!weak_sequence_ptr.get())
      break;

    PurgeDeletedAnimations();

    bool is_running = false;
    for (RunningAnimations::const_iterator iter = running_animations_.begin();
         iter != running_animations_.end(); ++iter) {
      if ((*iter).sequence() == animation_queue_[i].get()) {
        is_running = true;
        break;
      }
    }

    if (!is_running)
      delete RemoveAnimation(animation_queue_[i].get());
    else
      ++i;
  }
  animation_queue_.push_back(make_linked_ptr(sequence));
  ProcessQueue();
}

void LayerAnimator::ProcessQueue() {
  bool started_sequence = false;
  do {
    started_sequence = false;
    // Build a list of all currently animated properties.
    LayerAnimationElement::AnimatableProperties animated =
        LayerAnimationElement::UNKNOWN;
    for (RunningAnimations::const_iterator iter = running_animations_.begin();
         iter != running_animations_.end(); ++iter) {
      if (!(*iter).is_sequence_alive())
        continue;

      animated |= (*iter).sequence()->properties();
    }

    // Try to find an animation that doesn't conflict with an animated
    // property or a property that will be animated before it. Note: starting
    // the animation may indirectly cause more animations to be started, so we
    // need to operate on a copy.
    std::vector<base::WeakPtr<LayerAnimationSequence> > sequences;
    for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
         queue_iter != animation_queue_.end(); ++queue_iter)
      sequences.push_back((*queue_iter)->AsWeakPtr());

    for (size_t i = 0; i < sequences.size(); ++i) {
      if (!sequences[i].get() || !HasAnimation(sequences[i].get()))
        continue;

      if (!sequences[i]->HasConflictingProperty(animated)) {
        StartSequenceImmediately(sequences[i].get());
        started_sequence = true;
        break;
      }

      // Animation couldn't be started. Add its properties to the collection so
      // that we don't start a conflicting animation. For example, if our queue
      // has the elements { {T,B}, {B} } (that is, an element that animates both
      // the transform and the bounds followed by an element that animates the
      // bounds), and we're currently animating the transform, we can't start
      // the first element because it animates the transform, too. We cannot
      // start the second element, either, because the first element animates
      // bounds too, and needs to go first.
      animated |= sequences[i]->properties();
    }

    // If we started a sequence, try again. We may be able to start several.
  } while (started_sequence);
}

bool LayerAnimator::StartSequenceImmediately(LayerAnimationSequence* sequence) {
  PurgeDeletedAnimations();

  // Ensure that no one is animating one of the sequence's properties already.
  for (RunningAnimations::const_iterator iter = running_animations_.begin();
       iter != running_animations_.end(); ++iter) {
    if ((*iter).sequence()->HasConflictingProperty(sequence->properties()))
      return false;
  }

  // All clear, actually start the sequence. Note: base::TimeTicks::Now has
  // a resolution that can be as bad as 15ms. If this causes glitches in the
  // animations, this can be switched to HighResNow() (animation uses Now()
  // internally).
  // All LayerAnimators share the same AnimationContainer. Use the
  // last_tick_time() from there to ensure animations started during the same
  // event complete at the same time.
  base::TimeTicks start_time;
  if (is_animating() || adding_animations_)
    start_time = last_step_time_;
  else if (GetAnimationContainer()->is_running())
    start_time = GetAnimationContainer()->last_tick_time();
  else
    start_time = gfx::FrameTime::Now();

  if (!sequence->animation_group_id())
    sequence->set_animation_group_id(cc::AnimationIdProvider::NextGroupId());
  if (!sequence->waiting_for_group_start() ||
      sequence->IsFirstElementThreaded()) {
    sequence->set_start_time(start_time);
    sequence->Start(delegate());
  }
  running_animations_.push_back(
      RunningAnimation(sequence->AsWeakPtr()));

  // Need to keep a reference to the animation.
  AddToQueueIfNotPresent(sequence);

  // Ensure that animations get stepped at their start time.
  Step(start_time);

  return true;
}

void LayerAnimator::GetTargetValue(
    LayerAnimationElement::TargetValue* target) const {
  for (AnimationQueue::const_iterator iter = animation_queue_.begin();
       iter != animation_queue_.end(); ++iter) {
    (*iter)->GetTargetValue(target);
  }
}

void LayerAnimator::OnScheduled(LayerAnimationSequence* sequence) {
  if (observers_.might_have_observers()) {
    ObserverListBase<LayerAnimationObserver>::Iterator it(observers_);
    LayerAnimationObserver* obs;
    while ((obs = it.GetNext()) != NULL) {
      sequence->AddObserver(obs);
    }
  }
  sequence->OnScheduled();
}

void LayerAnimator::SetTransitionDuration(base::TimeDelta duration) {
  if (is_transition_duration_locked_)
    return;
  transition_duration_ = duration;
}

void LayerAnimator::ClearAnimationsInternal() {
  PurgeDeletedAnimations();

  // Abort should never affect the set of running animations, but just in case
  // clients are badly behaved, we will use a copy of the running animations.
  RunningAnimations running_animations_copy = running_animations_;
  for (size_t i = 0; i < running_animations_copy.size(); ++i) {
    if (!SAFE_INVOKE_BOOL(HasAnimation, running_animations_copy[i]))
      continue;

    scoped_ptr<LayerAnimationSequence> removed(
        RemoveAnimation(running_animations_copy[i].sequence()));
    if (removed.get())
      removed->Abort(delegate());
  }
  // This *should* have cleared the list of running animations.
  DCHECK(running_animations_.empty());
  running_animations_.clear();
  animation_queue_.clear();
  UpdateAnimationState();
}

void LayerAnimator::PurgeDeletedAnimations() {
  for (size_t i = 0; i < running_animations_.size();) {
    if (!running_animations_[i].is_sequence_alive())
      running_animations_.erase(running_animations_.begin() + i);
    else
      i++;
  }
}

LayerAnimator::RunningAnimation::RunningAnimation(
    const base::WeakPtr<LayerAnimationSequence>& sequence)
    : sequence_(sequence) {
}

LayerAnimator::RunningAnimation::~RunningAnimation() { }

}  // namespace ui
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root/ui/compositor/layer_animator.cc

DEFINITIONS
