Change AXTreeDelegate into AXTreeObserver.
It was awkward that BrowserAccessibilityManager and
AutomationAXTreeWrapper had to inherit from AXEventGenerator.
Now they can each own an AXEventGenerator but also be
AXTreeObservers, themselves.
[email protected]
Bug: none
Change-Id: Iac577b5ddcca892e809a9c02ce38d193297ecb80
Reviewed-on: https://chromium-review.googlesource.com/c/1357831
Reviewed-by: Dominic Mazzoni <[email protected]>
Reviewed-by: David Tseng <[email protected]>
Commit-Queue: Dominic Mazzoni <[email protected]>
Cr-Commit-Position: refs/heads/master@{#615728}diff --git a/ui/accessibility/ax_tree.h b/ui/accessibility/ax_tree.h
index c01aa3cb..c2b0d80 100644
--- a/ui/accessibility/ax_tree.h
+++ b/ui/accessibility/ax_tree.h
@@ -10,6 +10,7 @@
#include <set>
#include "base/containers/hash_tables.h"
+#include "base/observer_list.h"
#include "ui/accessibility/ax_export.h"
#include "ui/accessibility/ax_node.h"
#include "ui/accessibility/ax_node_data.h"
@@ -20,138 +21,9 @@
class AXTableInfo;
class AXTree;
+class AXTreeObserver;
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,
- ax::mojom::Role old_role,
- ax::mojom::Role new_role) {}
- virtual void OnStateChanged(AXTree* tree,
- AXNode* node,
- ax::mojom::State state,
- bool new_value) {}
- virtual void OnStringAttributeChanged(AXTree* tree,
- AXNode* node,
- ax::mojom::StringAttribute attr,
- const std::string& old_value,
- const std::string& new_value) {}
- virtual void OnIntAttributeChanged(AXTree* tree,
- AXNode* node,
- ax::mojom::IntAttribute attr,
- int32_t old_value,
- int32_t new_value) {}
- virtual void OnFloatAttributeChanged(AXTree* tree,
- AXNode* node,
- ax::mojom::FloatAttribute attr,
- float old_value,
- float new_value) {}
- virtual void OnBoolAttributeChanged(AXTree* tree,
- AXNode* node,
- ax::mojom::BoolAttribute attr,
- bool new_value) {}
- virtual void OnIntListAttributeChanged(
- AXTree* tree,
- AXNode* node,
- ax::mojom::IntListAttribute attr,
- const std::vector<int32_t>& old_value,
- const std::vector<int32_t>& new_value) {}
- virtual void OnStringListAttributeChanged(
- AXTree* tree,
- AXNode* node,
- ax::mojom::StringListAttribute 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.
@@ -170,8 +42,11 @@
explicit AXTree(const AXTreeUpdate& initial_state);
virtual ~AXTree();
- virtual void SetDelegate(AXTreeDelegate* delegate);
- AXTreeDelegate* delegate() const { return delegate_; }
+ void AddObserver(AXTreeObserver* observer);
+ bool HasObserver(AXTreeObserver* observer);
+ void RemoveObserver(const AXTreeObserver* observer);
+
+ base::ObserverList<AXTreeObserver>& observers() { return observers_; }
AXNode* root() const { return root_; }
@@ -327,7 +202,7 @@
std::vector<AXNode*>* new_children,
AXTreeUpdateState* update_state);
- AXTreeDelegate* delegate_ = nullptr;
+ base::ObserverList<AXTreeObserver> observers_;
AXNode* root_ = nullptr;
base::hash_map<int32_t, AXNode*> id_map_;
std::string error_;
