blob: d733df9fd1dd3012b00d556f669e2b59e55c0f29 [file] [log] [blame]
// 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 <stdint.h>
#include <set>
#include "base/containers/hash_tables.h"
#include "ui/accessibility/ax_export.h"
#include "ui/accessibility/ax_node_data.h"
#include "ui/accessibility/ax_tree_data.h"
#include "ui/accessibility/ax_tree_update.h"
namespace ui {
class AXNode;
class AXTree;
struct AXTreeUpdateState;
// Used when you want to be notified when changes happen to the tree.
//
// Some of the notifications are called in the middle of an update operation.
// Be careful, as the tree may be in an inconsistent state at this time;
// don't walk the parents and children at this time:
// OnNodeWillBeDeleted
// OnSubtreeWillBeDeleted
// OnNodeWillBeReparented
// OnSubtreeWillBeReparented
// OnNodeCreated
// OnNodeReparented
// OnNodeChanged
//
// In addition, one additional notification is fired at the end of an
// atomic update, and it provides a vector of nodes that were added or
// changed, for final postprocessing:
// OnAtomicUpdateFinished
//
class AX_EXPORT AXTreeDelegate {
public:
AXTreeDelegate();
virtual ~AXTreeDelegate();
// Called before a node's data gets updated.
virtual void OnNodeDataWillChange(AXTree* tree,
const AXNodeData& old_node_data,
const AXNodeData& new_node_data) = 0;
// Individual callbacks for every attribute of AXNodeData that can change.
virtual void OnRoleChanged(AXTree* tree,
AXNode* node,
AXRole old_role,
AXRole new_role) {}
virtual void OnStateChanged(AXTree* tree,
AXNode* node,
AXState state,
bool new_value) {}
virtual void OnStringAttributeChanged(AXTree* tree,
AXNode* node,
AXStringAttribute attr,
const std::string& old_value,
const std::string& new_value) {}
virtual void OnIntAttributeChanged(AXTree* tree,
AXNode* node,
AXIntAttribute attr,
int32_t old_value,
int32_t new_value) {}
virtual void OnFloatAttributeChanged(AXTree* tree,
AXNode* node,
AXFloatAttribute attr,
float old_value,
float new_value) {}
virtual void OnBoolAttributeChanged(AXTree* tree,
AXNode* node,
AXBoolAttribute attr,
bool new_value) {}
virtual void OnIntListAttributeChanged(
AXTree* tree,
AXNode* node,
AXIntListAttribute attr,
const std::vector<int32_t>& old_value,
const std::vector<int32_t>& new_value) {}
virtual void OnStringListAttributeChanged(
AXTree* tree,
AXNode* node,
AXStringListAttribute attr,
const std::vector<std::string>& old_value,
const std::vector<std::string>& new_value) {}
// Called when tree data changes.
virtual void OnTreeDataChanged(AXTree* tree,
const ui::AXTreeData& old_data,
const ui::AXTreeData& new_data) = 0;
// Called just before a node is deleted. Its id and data will be valid,
// but its links to parents and children are invalid. This is called
// in the middle of an update, the tree may be in an invalid state!
virtual void OnNodeWillBeDeleted(AXTree* tree, AXNode* node) = 0;
// Same as OnNodeWillBeDeleted, but only called once for an entire subtree.
// This is called in the middle of an update, the tree may be in an
// invalid state!
virtual void OnSubtreeWillBeDeleted(AXTree* tree, AXNode* node) = 0;
// Called just before a node is deleted for reparenting. See
// |OnNodeWillBeDeleted| for additional information.
virtual void OnNodeWillBeReparented(AXTree* tree, AXNode* node) = 0;
// Called just before a subtree is deleted for reparenting. See
// |OnSubtreeWillBeDeleted| for additional information.
virtual void OnSubtreeWillBeReparented(AXTree* tree, AXNode* node) = 0;
// Called immediately after a new node is created. The tree may be in
// the middle of an update, don't walk the parents and children now.
virtual void OnNodeCreated(AXTree* tree, AXNode* node) = 0;
// Called immediately after a node is reparented. The tree may be in the
// middle of an update, don't walk the parents and children now.
virtual void OnNodeReparented(AXTree* tree, AXNode* node) = 0;
// Called when a node changes its data or children. The tree may be in
// the middle of an update, don't walk the parents and children now.
virtual void OnNodeChanged(AXTree* tree, AXNode* node) = 0;
enum ChangeType {
NODE_CREATED,
SUBTREE_CREATED,
NODE_CHANGED,
NODE_REPARENTED,
SUBTREE_REPARENTED
};
struct Change {
Change(AXNode* node, ChangeType type) {
this->node = node;
this->type = type;
}
AXNode* node;
ChangeType type;
};
// Called at the end of the update operation. Every node that was added
// or changed will be included in |changes|, along with an enum indicating
// the type of change - either (1) a node was created, (2) a node was created
// and it's the root of a new subtree, or (3) a node was changed. Finally,
// a bool indicates if the root of the tree was changed or not.
virtual void OnAtomicUpdateFinished(AXTree* tree,
bool root_changed,
const std::vector<Change>& changes) = 0;
};
// 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 void SetDelegate(AXTreeDelegate* delegate);
AXTreeDelegate* delegate() const { return delegate_; }
AXNode* root() const { return root_; }
const AXTreeData& data() const { return data_; }
// Returns the AXNode with the given |id| if it is part of this AXTree.
AXNode* GetFromId(int32_t id) const;
// Returns true on success. If it returns false, it's a fatal error
// and this tree should be destroyed, and the source of the tree update
// should not be trusted any longer.
virtual bool Unserialize(const AXTreeUpdate& update);
virtual void UpdateData(const AXTreeData& data);
// Convert any rectangle from the local coordinate space of one node in
// the tree, to bounds in the coordinate space of the tree.
// If set, updates |offscreen| boolean to be true if the node is offscreen
// relative to its rootWebArea. Callers should initialize |offscreen|
// to false: this method may get called multiple times in a row and
// |offscreen| will be propagated.
// If |clip_bounds| is true, result bounds will be clipped.
gfx::RectF RelativeToTreeBounds(const AXNode* node,
gfx::RectF node_bounds,
bool* offscreen = nullptr,
bool clip_bounds = true) const;
// Get the bounds of a node in the coordinate space of the tree.
// If set, updates |offscreen| boolean to be true if the node is offscreen
// relative to its rootWebArea. Callers should initialize |offscreen|
// to false: this method may get called multiple times in a row and
// |offscreen| will be propagated.
// If |clip_bounds| is true, result bounds will be clipped.
gfx::RectF GetTreeBounds(const AXNode* node,
bool* offscreen = nullptr,
bool clip_bounds = true) const;
// Given a node ID attribute (one where IsNodeIdIntAttribute is true),
// and a destination node ID, return a set of all source node IDs that
// have that relationship attribute between them and the destination.
std::set<int32_t> GetReverseRelations(AXIntAttribute attr,
int32_t dst_id) const;
// Given a node ID list attribute (one where
// IsNodeIdIntListAttribute is true), and a destination node ID,
// return a set of all source node IDs that have that relationship
// attribute between them and the destination.
std::set<int32_t> GetReverseRelations(AXIntListAttribute attr,
int32_t dst_id) const;
// Return a multi-line indented string representation, for logging.
std::string ToString() const;
// A string describing the error from an unsuccessful Unserialize,
// for testing and debugging.
const std::string& error() const { return error_; }
int size() { return static_cast<int>(id_map_.size()); }
private:
AXNode* CreateNode(AXNode* parent,
int32_t id,
int32_t index_in_parent,
AXTreeUpdateState* update_state);
// This is called from within Unserialize(), it returns true on success.
bool UpdateNode(const AXNodeData& src,
bool is_new_root,
AXTreeUpdateState* update_state);
void CallNodeChangeCallbacks(AXNode* node, const AXNodeData& new_data);
void UpdateReverseRelations(AXNode* node, const AXNodeData& new_data);
void OnRootChanged();
// Notify the delegate that the subtree rooted at |node| will be destroyed,
// then call DestroyNodeAndSubtree on it.
void DestroySubtree(AXNode* node, AXTreeUpdateState* update_state);
// 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, AXTreeUpdateState* update_state);
// 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_t>& new_child_ids,
AXTreeUpdateState* update_state);
// 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_t>& new_child_ids,
std::vector<AXNode*>* new_children,
AXTreeUpdateState* update_state);
AXTreeDelegate* delegate_ = nullptr;
AXNode* root_ = nullptr;
base::hash_map<int32_t, AXNode*> id_map_;
std::string error_;
AXTreeData data_;
// Map from an int attribute (if IsNodeIdIntAttribute is true) to
// a reverse mapping from target nodes to source nodes.
std::map<AXIntAttribute, std::map<int32_t, std::set<int32_t>>>
int_reverse_relations_;
// Map from an int list attribute (if IsNodeIdIntListAttribute is true) to
// a reverse mapping from target nodes to source nodes.
std::map<AXIntListAttribute, std::map<int32_t, std::set<int32_t>>>
intlist_reverse_relations_;
};
} // namespace ui
#endif // UI_ACCESSIBILITY_AX_TREE_H_