// Copyright 2013 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_SOURCE_H_ #define UI_ACCESSIBILITY_AX_TREE_SOURCE_H_ #include #include #include #include "base/notreached.h" #include "third_party/skia/include/core/SkBitmap.h" #include "ui/accessibility/ax_node_data.h" #include "ui/accessibility/ax_tree_data.h" #include "ui/accessibility/ax_tree_source_observer.h" namespace ui { // An AXTreeSource is an abstract interface for a serializable // accessibility tree. The tree may be in some other format or // may be computed dynamically, but maintains the properties that // it's a strict tree, it has a unique id for each node, and all // of the accessibility information about a node can be serialized // as an AXNodeData. This is the primary interface to use when // an accessibility tree will be sent over an IPC before being // consumed. template class AXTreeSource { public: virtual ~AXTreeSource() = default; // Get the tree data and returns true if there is any data to copy. virtual bool GetTreeData(AXTreeData* data) const = 0; // Get the root of the tree. virtual AXNodeSource GetRoot() const = 0; // Get a node by its id. If no node by that id exists in the tree, return a // null node, i.e. one that will return false if you call IsValid on it. virtual AXNodeSource GetFromId(AXNodeID id) const = 0; // Return the id of a node. All ids must be positive integers; 0 is not a // valid ID. IDs are unique only across the current tree source, not across // tree sources. virtual AXNodeID GetId(AXNodeSource node) const = 0; // Append all children of |node| to |out_children|. virtual void GetChildren(AXNodeSource node, std::vector* out_children) const = 0; // Get the parent of |node|. virtual AXNodeSource GetParent(AXNodeSource node) const = 0; // Returns true if |node| is valid, and false if it's a null pointer or a // node object representing the null pointer. virtual bool IsValid(AXNodeSource node) const = 0; // Returns true if |node| is an ignored node virtual bool IsIgnored(AXNodeSource node) const = 0; // Returns true if two nodes are equal. virtual bool IsEqual(AXNodeSource node1, AXNodeSource node2) const = 0; // Return a AXNodeSource representing null. virtual AXNodeSource GetNull() const = 0; // Serialize one node in the tree. virtual void SerializeNode(AXNodeSource node, AXNodeData* out_data) const = 0; // Return a string useful for debugging a node. virtual std::string GetDebugString(AXNodeSource node) const { AXNodeData node_data; SerializeNode(node, &node_data); return node_data.ToString(); } // This is called by AXTreeSerializer when it serializes a tree and // discovers that a node previously in the tree is no longer part of // the tree. It can be used to allow an AXTreeSource to keep a cache // indexed by node ID and delete nodes when they're no longer needed. virtual void SerializerClearedNode(AXNodeID node_id) {} // The following methods should be overridden in order to add or remove an // `AXTreeSourceObserver`, which is notified when nodes are added, removed or // updated in this tree source. virtual void AddObserver(ui::AXTreeSourceObserver* observer) { NOTIMPLEMENTED(); } virtual void RemoveObserver( ui::AXTreeSourceObserver* observer) { NOTIMPLEMENTED(); } protected: AXTreeSource() {} }; } // namespace ui #endif // UI_ACCESSIBILITY_AX_TREE_SOURCE_H_