ax_tree_id.h

Go to the documentation of this file.

// Copyright 2018 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_ID_H_
#define UI_ACCESSIBILITY_AX_TREE_ID_H_
 
#include <string>
 
#include "ax_base_export.h"
#include "ax_enums.h"
#include "base/no_destructor.h"
#include "base/simple_token.h"
 
namespace ui {
 
// A unique ID representing an accessibility tree.
class AX_BASE_EXPORT AXTreeID {
 public:
  // Create an Unknown AXTreeID.
  AXTreeID();
 
  // Copy constructor.
  AXTreeID(const AXTreeID& other);
 
  // Create a new unique AXTreeID.
  static AXTreeID CreateNewAXTreeID();
 
  // Unserialize an AXTreeID from a string. This is used so that tree IDs
  // can be stored compactly as a string attribute in an AXNodeData, and
  // so that AXTreeIDs can be passed to JavaScript bindings in the
  // automation API.
  static AXTreeID FromString(const std::string& string);
 
  // Convenience method to unserialize an AXTreeID from an SimpleToken.
  static AXTreeID FromToken(const base::SimpleToken& token);
 
  AXTreeID& operator=(const AXTreeID& other);
 
  std::string ToString() const;
 
  ax::mojom::AXTreeIDType type() const { return type_; }
  const std::optional<base::SimpleToken>& token() const { return token_; }
 
  bool operator==(const AXTreeID& rhs) const;
  bool operator!=(const AXTreeID& rhs) const;
  bool operator<(const AXTreeID& rhs) const;
  bool operator<=(const AXTreeID& rhs) const;
  bool operator>(const AXTreeID& rhs) const;
  bool operator>=(const AXTreeID& rhs) const;
 
 private:
  explicit AXTreeID(ax::mojom::AXTreeIDType type);
  explicit AXTreeID(const std::string& string);
 
  friend class base::NoDestructor<AXTreeID>;
  friend void swap(AXTreeID& first, AXTreeID& second);
 
  ax::mojom::AXTreeIDType type_;
  std::optional<base::SimpleToken> token_ = std::nullopt;
};
 
// For use in std::unordered_map.
struct AX_BASE_EXPORT AXTreeIDHash {
  size_t operator()(const ui::AXTreeID& tree_id) const;
};
 
AX_BASE_EXPORT std::ostream& operator<<(std::ostream& stream,
                                        const AXTreeID& value);
 
// The value to use when an AXTreeID is unknown.
AX_BASE_EXPORT extern const AXTreeID& AXTreeIDUnknown();
 
}  // namespace ui
 
#endif  // UI_ACCESSIBILITY_AX_TREE_ID_H_