1 // Copyright 2016 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_COMBINER_H_ 6 #define UI_ACCESSIBILITY_AX_TREE_COMBINER_H_ 7 8 #include <vector> 9 10 #include "ui/accessibility/ax_export.h" 11 #include "ui/accessibility/ax_tree_id_registry.h" 12 #include "ui/accessibility/ax_tree_update.h" 13 14 namespace ui { 15 16 // This helper class takes multiple accessibility trees that reference each 17 // other via tree IDs, and combines them into a single accessibility tree 18 // that spans all of them. 19 // 20 // Since node IDs are relative to each ID, it has to renumber all of the IDs 21 // and update all of the attributes that reference IDs of other nodes to 22 // ensure they point to the right node. 23 // 24 // It also makes sure the final combined tree points to the correct focused 25 // node across all of the trees based on the focused tree ID of the root tree. 26 class AX_EXPORT AXTreeCombiner { 27 public: 28 AXTreeCombiner(); 29 ~AXTreeCombiner(); 30 31 void AddTree(const AXTreeUpdate& tree, bool is_root); 32 bool Combine(); 33 combined()34 const AXTreeUpdate& combined() { return combined_; } 35 36 private: 37 int32_t MapId(AXTreeID tree_id, int32_t node_id); 38 39 void ProcessTree(const AXTreeUpdate* tree); 40 41 std::vector<ui::AXTreeUpdate> trees_; 42 AXTreeID root_tree_id_; 43 int32_t next_id_ = 1; 44 std::map<AXTreeID, const AXTreeUpdate*> tree_id_map_; 45 std::map<std::pair<AXTreeID, int32_t>, int32_t> tree_id_node_id_map_; 46 AXTreeUpdate combined_; 47 }; 48 49 50 } // namespace ui 51 52 #endif // UI_ACCESSIBILITY_AX_TREE_COMBINER_H_ 53