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- // Copyright 2022 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_MANAGER_BASE_H_
- #define UI_ACCESSIBILITY_AX_TREE_MANAGER_BASE_H_
- #include <memory>
- #include "base/containers/flat_map.h"
- #include "third_party/abseil-cpp/absl/types/optional.h"
- #include "ui/accessibility/ax_export.h"
- #include "ui/accessibility/ax_node_data.h"
- #include "ui/accessibility/ax_tree.h"
- #include "ui/accessibility/ax_tree_data.h"
- #include "ui/accessibility/ax_tree_id.h"
- #include "ui/accessibility/ax_tree_update.h"
- namespace ui {
- class AXNode;
- // A class that owns an accessibility tree and manages its connections to other
- // accessibility trees. Each accessibility tree could be connected to one parent
- // tree and multiple child trees, the whole collection essentially being a
- // forest of trees representing user interface elements. Each tree is typically
- // backed by a rendering surface.
- //
- // This class is movable but not copyable.
- class AX_EXPORT AXTreeManagerBase final {
- public:
- // Returns the manager of the tree with the given ID, if any.
- static AXTreeManagerBase* GetManager(const AXTreeID& tree_id);
- // Returns the node identified by the given `tree_id` and `node_id`. This
- // allows for callers to access nodes outside of their own tree.
- static AXNode* GetNodeFromTree(const AXTreeID& tree_id,
- const AXNodeID& node_id);
- // This default constructor does not create an empty accessibility tree. Call
- // `SetTree` if you need to manage a specific tree.
- AXTreeManagerBase();
- explicit AXTreeManagerBase(std::unique_ptr<AXTree> tree);
- explicit AXTreeManagerBase(const AXTreeUpdate& initial_state);
- virtual ~AXTreeManagerBase();
- AXTreeManagerBase(const AXTreeManagerBase&) = delete;
- AXTreeManagerBase& operator=(const AXTreeManagerBase&) = delete;
- AXTreeManagerBase(AXTreeManagerBase&& manager);
- AXTreeManagerBase& operator=(AXTreeManagerBase&& manager);
- // Returns a pointer to the managed tree, if any.
- AXTree* GetTree() const;
- // Takes ownership of a new accessibility tree and returns the one that is
- // currently being managed. It is considered an error to pass an empty
- // unique_ptr for `tree`. If no tree is currently being managed, returns an
- // empty unique_ptr.
- std::unique_ptr<AXTree> SetTree(std::unique_ptr<AXTree> tree);
- std::unique_ptr<AXTree> SetTree(const AXTreeUpdate& initial_state);
- // Detaches the managed tree, if any.
- std::unique_ptr<AXTree> ReleaseTree();
- // Returns a snapshot of the managed tree by serializing it into an
- // `AXTreeUpdate`.
- AXTreeUpdate SnapshotTree() const;
- // Tries to update the managed tree by unserializing and applying the provided
- // `update`. Returns a boolean value indicating success or failure.
- bool ApplyTreeUpdate(const AXTreeUpdate& update);
- // Returns the ID of the managed tree.
- //
- // Note that tree IDs are expensive to copy, hence the use of a const
- // reference.
- const AXTreeID& GetTreeID() const;
- // Returns the ID of the parent tree.
- //
- // Note that tree IDs are expensive to copy, hence the use of a const
- // reference.
- const AXTreeID& GetParentTreeID() const;
- // Returns the managed tree's data.
- const AXTreeData& GetTreeData() const;
- // Returns the node identified with the given `node_id).
- AXNode* GetNode(const AXNodeID& node_id) const;
- // Returns the rootnode of the managed tree. The rootnode could be nullptr
- // during some `AXTreeObserver` callbacks.
- AXNode* GetRoot() const;
- // Returns the rootnode of the child tree hosted at `host_node_id`. The
- // rootnode could be nullptr during some `AXTreeObserver` callbacks.
- AXNode* GetRootOfChildTree(const AXNodeID& host_node_id) const;
- AXNode* GetRootOfChildTree(const AXNode& host_node) const;
- // If this tree has a parent tree, returns the node in the parent tree that
- // is hosting the current tree.
- AXNode* GetHostNode() const;
- // Attaches the given child tree to the given host node. Returns a boolean
- // indicating success or failure.
- bool AttachChildTree(const AXNodeID& host_node_id,
- AXTreeManagerBase& child_manager);
- bool AttachChildTree(AXNode& host_node, AXTreeManagerBase& child_manager);
- // Creates a child tree based on `initial_state` and attaches it to the given
- // host node. Returns the child tree's manager if successful.
- absl::optional<AXTreeManagerBase> AttachChildTree(
- const AXNodeID& host_node_id,
- const AXTreeUpdate& initial_state);
- absl::optional<AXTreeManagerBase> AttachChildTree(
- AXNode& host_node,
- const AXTreeUpdate& initial_state);
- // Detaches the child tree hosted by the given host node, returning a pointer
- // to its manager.
- AXTreeManagerBase* DetachChildTree(const AXNodeID& host_node_id);
- AXTreeManagerBase* DetachChildTree(AXNode& host_node);
- private:
- static base::flat_map<AXTreeID, AXTreeManagerBase*>&
- GetTreeManagerMapInstance();
- std::unique_ptr<AXTree> tree_;
- };
- } // namespace ui
- #endif // UI_ACCESSIBILITY_AX_TREE_MANAGER_BASE_H_
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