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- // Copyright 2014 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_ACTION_HANDLER_REGISTRY_H_
- #define UI_ACCESSIBILITY_AX_ACTION_HANDLER_REGISTRY_H_
- #include <cstdint>
- #include <map>
- #include <utility>
- #include "base/observer_list.h"
- #include "ui/accessibility/ax_action_handler.h"
- #include "ui/accessibility/ax_base_export.h"
- #include "ui/accessibility/ax_tree_id.h"
- namespace base {
- template <typename T, typename O>
- class NoDestructor;
- } // namespace base
- namespace ui {
- class AXActionHandlerBase;
- // An observer is informed of all automation actions.
- class AXActionHandlerObserver : public base::CheckedObserver {
- public:
- // This method is intended to route actions to their final destinations. The
- // routing is asynchronous and we do not know which observers intend to
- // respond to which actions -- so we forward all actions to all observers.
- // Only the observer that owns the unique |tree_id| will perform the action.
- virtual void PerformAction(const ui::AXActionData& action_data) = 0;
- };
- // This class generates and saves a runtime id for an accessibility tree.
- // It provides a few distinct forms of generating an id:
- // - from a frame id (which consists of a process and routing id)
- // - from a backing |AXActionHandlerBase| object
- //
- // The first form allows underlying instances to change but refer to the same
- // frame.
- // The second form allows this registry to track the object for later retrieval.
- class AX_BASE_EXPORT AXActionHandlerRegistry final {
- public:
- using FrameID = std::pair<int, int>;
- // Get the single instance of this class.
- static AXActionHandlerRegistry* GetInstance();
- virtual ~AXActionHandlerRegistry();
- AXActionHandlerRegistry(const AXActionHandlerRegistry&) = delete;
- AXActionHandlerRegistry& operator=(const AXActionHandlerRegistry&) = delete;
- // Gets the frame id based on an ax tree id.
- FrameID GetFrameID(const AXTreeID& ax_tree_id);
- // Gets an ax tree id from a frame id.
- AXTreeID GetAXTreeID(FrameID frame_id);
- // Retrieve an |AXActionHandlerBase| based on an ax tree id.
- AXActionHandlerBase* GetActionHandler(AXTreeID ax_tree_id);
- // Removes an ax tree id, and its associated delegate and frame id (if it
- // exists).
- void RemoveAXTreeID(AXTreeID ax_tree_id);
- // Associate a frame id with an ax tree id.
- void SetFrameIDForAXTreeID(const FrameID& frame_id,
- const AXTreeID& ax_tree_id);
- void AddObserver(AXActionHandlerObserver* observer);
- void RemoveObserver(AXActionHandlerObserver* observer);
- // Calls PerformAction on all observers.
- void PerformAction(const ui::AXActionData& action_data);
- private:
- friend base::NoDestructor<AXActionHandlerRegistry, std::nullptr_t>;
- // Allows registration of tree ids meant to be internally by AXActionHandler*.
- // These typically involve the creation of a new tree id.
- friend AXActionHandler;
- friend AXActionHandlerBase;
- AXActionHandlerRegistry();
- // Get or create a ax tree id keyed on |handler|.
- AXTreeID GetOrCreateAXTreeID(AXActionHandlerBase* handler);
- // Set a mapping between an AXTreeID and AXActionHandlerBase explicitly.
- void SetAXTreeID(const AXTreeID& ax_tree_id,
- AXActionHandlerBase* action_handler);
- // Maps an accessibility tree to its frame via ids.
- std::map<AXTreeID, FrameID> ax_tree_to_frame_id_map_;
- // Maps frames to an accessibility tree via ids.
- std::map<FrameID, AXTreeID> frame_to_ax_tree_id_map_;
- // Maps an id to its handler.
- std::map<AXTreeID, AXActionHandlerBase*> id_to_action_handler_;
- // Tracks all observers.
- base::ObserverList<AXActionHandlerObserver> observers_;
- };
- } // namespace ui
- #endif // UI_ACCESSIBILITY_AX_ACTION_HANDLER_REGISTRY_H_
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