// Copyright 2011 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 CC_TREES_TREE_SYNCHRONIZER_H_
#define CC_TREES_TREE_SYNCHRONIZER_H_

#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "cc/base/cc_export.h"
#include "cc/base/scoped_ptr_hash_map.h"

namespace cc {

class LayerImpl;
class LayerTreeImpl;
class Layer;

class CC_EXPORT TreeSynchronizer {
 public:
  // Accepts a Layer tree and returns a reference to a LayerImpl tree that
  // duplicates the structure of the Layer tree, reusing the LayerImpls in the
  // tree provided by old_layer_impl_root if possible.
  static scoped_ptr<LayerImpl> SynchronizeTrees(
      Layer* layer_root,
      scoped_ptr<LayerImpl> old_layer_impl_root,
      LayerTreeImpl* tree_impl);
  static scoped_ptr<LayerImpl> SynchronizeTrees(
      LayerImpl* layer_root,
      scoped_ptr<LayerImpl> old_layer_impl_root,
      LayerTreeImpl* tree_impl);

  // Pushes properties from a Layer or LayerImpl tree to a structurally
  // equivalent LayerImpl tree.
  static void PushProperties(Layer* layer_root,
                             LayerImpl* layer_impl_root);
  static void PushProperties(LayerImpl* layer_root, LayerImpl* layer_impl_root);

 private:
  TreeSynchronizer();  // Not instantiable.

  static void SetNumDependentsNeedPushProperties(Layer* layer, size_t num);
  static void SetNumDependentsNeedPushProperties(LayerImpl* layer, size_t num);

  template <typename LayerType>
  static void PushPropertiesInternal(
      LayerType* layer,
      LayerImpl* layer_impl,
      size_t* num_dependents_need_push_properties_for_parent);

  DISALLOW_COPY_AND_ASSIGN(TreeSynchronizer);
};

}  // namespace cc

#endif  // CC_TREES_TREE_SYNCHRONIZER_H_