1// Copyright 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef UI_ACCESSIBILITY_AX_TREE_SOURCE_H_
6#define UI_ACCESSIBILITY_AX_TREE_SOURCE_H_
7
8#include <vector>
9
10#include "ui/accessibility/ax_node_data.h"
11
12namespace ui {
13
14// An AXTreeSource is an abstract interface for a serializable
15// accessibility tree. The tree may be in some other format or
16// may be computed dynamically, but maintains the properties that
17// it's a strict tree, it has a unique id for each node, and all
18// of the accessibility information about a node can be serialized
19// as an AXNodeData. This is the primary interface to use when
20// an accessibility tree will be sent over an IPC before being
21// consumed.
22template<typename AXNodeSource>
23class AXTreeSource {
24 public:
25  virtual ~AXTreeSource() {}
26
27  // Get the root of the tree.
28  virtual AXNodeSource GetRoot() const = 0;
29
30  // Get a node by its id. If no node by that id exists in the tree, return a
31  // null node, i.e. one that will return false if you call IsValid on it.
32  virtual AXNodeSource GetFromId(int32 id) const = 0;
33
34  // Return the id of a node. All ids must be positive integers.
35  virtual int32 GetId(AXNodeSource node) const = 0;
36
37  // Append all children of |node| to |out_children|.
38  virtual void GetChildren(AXNodeSource node,
39                           std::vector<AXNodeSource>* out_children) const = 0;
40
41  // Get the parent of |node|.
42  virtual AXNodeSource GetParent(AXNodeSource node) const = 0;
43
44  // Returns true if |node| is valid, and false if it's a null pointer or a
45  // node object representing the null pointer.
46  virtual bool IsValid(AXNodeSource node) const = 0;
47
48  // Returns true if two nodes are equal.
49  virtual bool IsEqual(AXNodeSource node1,
50                       AXNodeSource node2) const = 0;
51
52  // Return a AXNodeSource representing null.
53  virtual AXNodeSource GetNull() const = 0;
54
55  // Serialize one node in the tree.
56  virtual void SerializeNode(AXNodeSource node, AXNodeData* out_data) const = 0;
57
58 protected:
59  AXTreeSource() {}
60};
61
62}  // namespace ui
63
64#endif  // UI_ACCESSIBILITY_AX_TREE_SOURCE_H_
65