ui/accessibility/ax_tree_source.h

   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
  12 namespace 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.
  22 template<typename AXNodeSource>
  23 class 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_