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mojo/services/view_manager/animation_runner.h

+// Copyright 2014 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.
+
+#ifndef SERVICES_VIEW_MANAGER_ANIMATION_RUNNER_H_
+#define SERVICES_VIEW_MANAGER_ANIMATION_RUNNER_H_
+
+#include <algorithm>
+#include <map>
+#include <set>
+#include <vector>
+
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/observer_list.h"
+#include "base/time/time.h"
+
+namespace mojo {
+class AnimationGroup;
+}
+
+namespace view_manager {
+
+class AnimationRunnerObserver;
+class ScheduledAnimationGroup;
+class ServerView;
+
+// AnimationRunner is responsible for maintaing and running a set of animations.
+// The animations are represented as a set of AnimationGroups. New animations
+// are scheduled by way of Schedule(). A |view| may only have one animation
+// running at a time. Schedule()ing a new animation for a view already animating
+// implicitly cancels the current animation for the view. Animations progress
+// by way of the Tick() function.
+class AnimationRunner {
+ public:
+  using AnimationId = uint32_t;
+  using ViewAndAnimationPair =
+      std::pair<ServerView*, const mojo::AnimationGroup*>;
+
+  explicit AnimationRunner(base::TimeTicks now);
+  ~AnimationRunner();
+
+  void AddObserver(AnimationRunnerObserver* observer);
+  void RemoveObserver(AnimationRunnerObserver* observer);
+
+  // Schedules animations. If any of the groups are not valid no animations are
+  // scheuled and 0 is returned. If there is an existing animation in progress
+  // for any of the views it is canceled and any properties that were animating
+  // but are no longer animating are set to their target value.
+  AnimationId Schedule(const std::vector<ViewAndAnimationPair>& views,
+                       base::TimeTicks now);
+
+  // Cancels an animation scheduled by an id that was previously returned from
+  // Schedule().
+  void CancelAnimation(AnimationId id);
+
+  // Cancels the animation scheduled for |view|. Does nothing if there is no
+  // animation scheduled for |view|. This does not change |view|. That is, any
+  // in progress animations are stopped.
+  void CancelAnimationForView(ServerView* view);
+
+  // Advance the animations updating values appropriately.
+  void Tick(base::TimeTicks time);
+
+  // Returns true if there are animations currently scheduled.
+  bool HasAnimations() const { return !view_to_animation_map_.empty(); }
+
+  // Returns true if the animation identified by |id| is valid and animating.
+  bool IsAnimating(AnimationId id) const {
+    return id_to_views_map_.count(id) > 0;
+  }
+
+  // Returns the views that are currently animating for |id|. Returns an empty
+  // set if |id| does not identify a valid animation.
+  std::set<ServerView*> GetViewsAnimating(AnimationId id) {
+    return IsAnimating(id) ? id_to_views_map_.find(id)->second
+                           : std::set<ServerView*>();
+  }
+
+ private:
+  enum CancelSource {
+    // Cancel is the result of scheduling another animation for the view.
+    CANCEL_SOURCE_SCHEDULE,
+
+    // Cancel originates from an explicit call to cancel.
+    CANCEL_SOURCE_CANCEL,
+  };
+
+  using ViewToAnimationMap =
+      base::ScopedPtrHashMap<ServerView*, ScheduledAnimationGroup>;
+  using IdToViewsMap = std::map<AnimationId, std::set<ServerView*>>;
+
+  void CancelAnimationForViewImpl(ServerView* view, CancelSource source);
+
+  // Removes |view| from both |view_to_animation_map_| and |id_to_views_map_|.
+  // Returns true if there are no more views animating with the animation id
+  // the view is associated with.
+  bool RemoveViewFromMaps(ServerView* view);
+
+  AnimationId next_id_;
+
+  base::TimeTicks last_tick_time_;
+
+  ObserverList<AnimationRunnerObserver> observers_;
+
+  ViewToAnimationMap view_to_animation_map_;
+
+  IdToViewsMap id_to_views_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(AnimationRunner);
+};
+
+}  // namespace view_manager
+
+#endif  // SERVICES_VIEW_MANAGER_ANIMATION_RUNNER_H_