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