ui/accessibility/ax_tree_source.h

// Copyright 2013 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 UI_ACCESSIBILITY_AX_TREE_SOURCE_H_
#define UI_ACCESSIBILITY_AX_TREE_SOURCE_H_

#include "ui/accessibility/ax_node_data.h"

namespace ui {

// An AXTreeSource is an abstract interface for a serializable
// accessibility tree. The tree may be in some other format or
// may be computed dynamically, but maintains the properties that
// it's a strict tree, it has a unique id for each node, and all
// of the accessibility information about a node can be serialized
// as an AXNodeData. This is the primary interface to use when
// an accessibility tree will be sent over an IPC before being
// consumed.
template<class AXNodeSource>
class AX_EXPORT AXTreeSource {
 public:
  virtual ~AXTreeSource() {}
  virtual AXNodeSource* GetFromId(int32 id) const = 0;
  virtual int32 GetId(const AXNodeSource* node) const = 0;
  virtual int GetChildCount(const AXNodeSource* node) const = 0;
  virtual AXNodeSource* GetChildAtIndex(const AXNodeSource* node, int index)
      const = 0;

  // Returns the id of this node's parent, or 0 if it doesn't have a parent.
  virtual int32 GetParentId(const AXNodeSource* node) const = 0;

  // Serialize one node in the tree.
  virtual void SerializeNode(
      const AXNodeSource* node, AXNodeData* out_data) const = 0;

 protected:
  AXTreeSource() {}
};

}  // namespace ui

#endif  // UI_ACCESSIBILITY_AX_TREE_SOURCE_H_