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// 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_H_
#define UI_ACCESSIBILITY_AX_TREE_H_
#include "base/containers/hash_tables.h"
#include "ui/accessibility/ax_export.h"
#include "ui/accessibility/ax_tree.h"
#include "ui/accessibility/ax_tree_update.h"
namespace ui {
class AXNode;
// AXTree is a live, managed tree of AXNode objects that can receive
// updates from another AXTreeSource via AXTreeUpdates, and it can be
// used as a source for sending updates to another client tree.
// It's designed to be subclassed to implement support for native
// accessibility APIs on a specific platform.
class AX_EXPORT AXTree {
public:
AXTree();
explicit AXTree(const AXTreeUpdate& initial_state);
virtual ~AXTree();
virtual AXNode* GetRoot() const;
virtual AXNode* GetFromId(int32 id) const;
virtual bool Unserialize(const AXTreeUpdate& update);
protected:
// Subclasses can override this to use a subclass of AXNode.
virtual AXNode* CreateNode(AXNode* parent, int32 id, int32 index_in_parent);
// This is called from within Unserialize(), it returns true on success.
// Subclasses can override this to do additional processing.
virtual bool UpdateNode(const AXNodeData& src);
// Subclasses can override this to do special behavior when the root changes.
virtual void OnRootChanged();
private:
// Convenience function to create a node and call Initialize on it.
AXNode* CreateAndInitializeNode(
AXNode* parent, int32 id, int32 index_in_parent);
// Call Destroy() on |node|, and delete it from the id map, and then
// call recursively on all nodes in its subtree.
void DestroyNodeAndSubtree(AXNode* node);
// Iterate over the children of |node| and for each child, destroy the
// child and its subtree if its id is not in |new_child_ids|. Returns
// true on success, false on fatal error.
bool DeleteOldChildren(AXNode* node,
const std::vector<int32> new_child_ids);
// Iterate over |new_child_ids| and populate |new_children| with
// pointers to child nodes, reusing existing nodes already in the tree
// if they exist, and creating otherwise. Reparenting is disallowed, so
// if the id already exists as the child of another node, that's an
// error. Returns true on success, false on fatal error.
bool CreateNewChildVector(AXNode* node,
const std::vector<int32> new_child_ids,
std::vector<AXNode*>* new_children);
AXNode* root_;
base::hash_map<int32, AXNode*> id_map_;
};
} // namespace ui
#endif // UI_ACCESSIBILITY_AX_TREE_H_