fix: Add list box support to the platform adapters

Author: DataTriny

platforms/macos/README.md

@@ -1,3 +1,7 @@
 # AccessKit macOS adapter
 
 This is the macOS adapter for [AccessKit](https://accesskit.dev/). It exposes an AccessKit accessibility tree through the Cocoa `NSAccessibility` protocol.
+
+## Known issues
+
+- The selected state of ListBox items is not reported ([#520](https://github.com/AccessKit/accesskit/issues/520))

platforms/macos/src/event.rs

@@ -137,6 +137,7 @@ pub(crate) struct EventGenerator {
     context: Rc<Context>,
     events: Vec<QueuedEvent>,
     text_changed: HashSet<NodeId>,
+    selected_rows_changed: HashSet<NodeId>,
 }
 
 impl EventGenerator {
@@ -145,6 +146,7 @@ impl EventGenerator {
             context,
             events: Vec::new(),
             text_changed: HashSet::new(),
+            selected_rows_changed: HashSet::new(),
         }
     }
 
@@ -181,6 +183,30 @@ impl EventGenerator {
             self.insert_text_change_if_needed_parent(node);
         }
     }
+
+    fn enqueue_selected_rows_change_if_needed_parent(&mut self, node: Node) {
+        if !node.is_container_with_selectable_children() {
+            return;
+        }
+        let id = node.id();
+        if self.selected_rows_changed.contains(&id) {
+            return;
+        }
+        self.events.push(QueuedEvent::Generic {
+            node_id: id,
+            notification: unsafe { NSAccessibilitySelectedRowsChangedNotification },
+        });
+        self.selected_rows_changed.insert(id);
+    }
+
+    fn enqueue_selected_rows_change_if_needed(&mut self, node: &Node) {
+        if !node.is_item_like() {
+            return;
+        }
+        if let Some(node) = node.selection_container(&filter) {
+            self.enqueue_selected_rows_change_if_needed_parent(node);
+        }
+    }
 }
 
 impl TreeChangeHandler for EventGenerator {
@@ -189,6 +215,9 @@ impl TreeChangeHandler for EventGenerator {
         if filter(node) != FilterResult::Include {
             return;
         }
+        if let Some(true) = node.is_selected() {
+            self.enqueue_selected_rows_change_if_needed(node);
+        }
         if node.value().is_some() && node.live() != Live::Off {
             self.events
                 .push(QueuedEvent::live_region_announcement(node));
@@ -199,7 +228,14 @@ impl TreeChangeHandler for EventGenerator {
         if old_node.raw_value() != new_node.raw_value() {
             self.insert_text_change_if_needed(new_node);
         }
+        let old_node_was_filtered_out = filter(old_node) != FilterResult::Include;
         if filter(new_node) != FilterResult::Include {
+            if !old_node_was_filtered_out
+                && old_node.is_item_like()
+                && old_node.is_selected() == Some(true)
+            {
+                self.enqueue_selected_rows_change_if_needed(old_node);
+            }
             return;
         }
         let node_id = new_node.id();
@@ -230,11 +266,17 @@ impl TreeChangeHandler for EventGenerator {
             && new_node.live() != Live::Off
             && (new_node.value() != old_node.value()
                 || new_node.live() != old_node.live()
-                || filter(old_node) != FilterResult::Include)
+                || old_node_was_filtered_out)
         {
             self.events
                 .push(QueuedEvent::live_region_announcement(new_node));
         }
+        if new_node.is_item_like()
+            && (new_node.is_selected() != old_node.is_selected()
+                || (old_node_was_filtered_out && new_node.is_selected() == Some(true)))
+        {
+            self.enqueue_selected_rows_change_if_needed(new_node);
+        }
     }
 
     fn focus_moved(&mut self, _old_node: Option<&Node>, new_node: Option<&Node>) {
@@ -248,6 +290,9 @@ impl TreeChangeHandler for EventGenerator {
 
     fn node_removed(&mut self, node: &Node) {
         self.insert_text_change_if_needed(node);
+        if let Some(true) = node.is_selected() {
+            self.enqueue_selected_rows_change_if_needed(node);
+        }
         self.events.push(QueuedEvent::NodeDestroyed(node.id()));
     }
 }

platforms/macos/src/node.rs

@@ -411,6 +411,22 @@ declare_class!(
             self.children_internal()
         }
 
+        #[method_id(accessibilitySelectedChildren)]
+        fn selected_children(&self) -> Option<Id<NSArray<PlatformNode>>> {
+            self.resolve_with_context(|node, context| {
+                if !node.is_container_with_selectable_children() {
+                    return None;
+                }
+                let platform_nodes = node
+                    .items(filter)
+                    .filter(|item| item.is_selected() == Some(true))
+                    .map(|child| context.get_or_create_platform_node(child.id()))
+                    .collect::<Vec<Id<PlatformNode>>>();
+                Some(NSArray::from_vec(platform_nodes))
+            })
+            .flatten()
+        }
+
         #[method(accessibilityFrame)]
         fn frame(&self) -> NSRect {
             self.resolve_with_context(|node, context| {
@@ -814,6 +830,75 @@ declare_class!(
                 .unwrap_or(false)
         }
 
+        #[method(isAccessibilitySelected)]
+        fn is_selected(&self) -> bool {
+            self.resolve(|node| node.is_selected()).flatten().unwrap_or(false)
+        }
+
+        #[method(setAccessibilitySelected:)]
+        fn set_selected(&self, selected: bool) {
+            self.resolve_with_context(|node, context| {
+                if !node.is_clickable() || !node.is_selectable() {
+                    return;
+                }
+                if node.is_selected() == Some(selected) {
+                    return;
+                }
+                context.do_action(ActionRequest {
+                    action: Action::Click,
+                    target: node.id(),
+                    data: None,
+                });
+            });
+        }
+
+        #[method_id(accessibilityRows)]
+        fn rows(&self) -> Option<Id<NSArray<PlatformNode>>> {
+            self.resolve_with_context(|node, context| {
+                if !node.is_container_with_selectable_children() {
+                    return None;
+                }
+                let platform_nodes = node
+                    .items(filter)
+                    .map(|child| context.get_or_create_platform_node(child.id()))
+                    .collect::<Vec<Id<PlatformNode>>>();
+                Some(NSArray::from_vec(platform_nodes))
+            })
+            .flatten()
+        }
+
+        #[method_id(accessibilitySelectedRows)]
+        fn selected_rows(&self) -> Option<Id<NSArray<PlatformNode>>> {
+            self.resolve_with_context(|node, context| {
+                if !node.is_container_with_selectable_children() {
+                    return None;
+                }
+                let platform_nodes = node
+                    .items(filter)
+                    .filter(|item| item.is_selected() == Some(true))
+                    .map(|child| context.get_or_create_platform_node(child.id()))
+                    .collect::<Vec<Id<PlatformNode>>>();
+                Some(NSArray::from_vec(platform_nodes))
+            })
+            .flatten()
+        }
+
+        #[method(accessibilityPerformPick)]
+        fn pick(&self) -> bool {
+            self.resolve_with_context(|node, context| {
+                let selectable = node.is_clickable() && node.is_selectable();
+                if selectable {
+                    context.do_action(ActionRequest {
+                        action: Action::Click,
+                        target: node.id(),
+                        data: None,
+                    });
+                }
+                selectable
+            })
+            .unwrap_or(false)
+        }
+
         #[method(isAccessibilitySelectorAllowed:)]
         fn is_selector_allowed(&self, selector: Sel) -> bool {
             self.resolve(|node| {
@@ -850,9 +935,23 @@ declare_class!(
                     // the expected VoiceOver behavior.
                     return node.supports_text_ranges() && !node.is_read_only();
                 }
+                if selector == sel!(isAccessibilitySelected) {
+                    return node.is_selectable();
+                }
+                if selector == sel!(accessibilityRows)
+                    || selector == sel!(accessibilitySelectedRows)
+                {
+                    return node.is_container_with_selectable_children()
+                }
+                if selector == sel!(setAccessibilitySelected:)
+                    || selector == sel!(accessibilityPerformPick)
+                {
+                    return node.is_clickable() && node.is_selectable();
+                }
                 selector == sel!(accessibilityParent)
                     || selector == sel!(accessibilityChildren)
                     || selector == sel!(accessibilityChildrenInNavigationOrder)
+                    || selector == sel!(accessibilitySelectedChildren)
                     || selector == sel!(accessibilityFrame)
                     || selector == sel!(accessibilityRole)
                     || selector == sel!(accessibilitySubrole)

platforms/unix/src/atspi/bus.rs

@@ -119,6 +119,13 @@ impl Bus {
             )
             .await?;
         }
+        if new_interfaces.contains(Interface::Selection) {
+            self.register_interface(
+                &path,
+                SelectionInterface::new(bus_name.clone(), node.clone()),
+            )
+            .await?;
+        }
         if new_interfaces.contains(Interface::Text) {
             self.register_interface(&path, TextInterface::new(node.clone()))
                 .await?;
@@ -164,6 +171,10 @@ impl Bus {
             self.unregister_interface::<ComponentInterface>(&path)
                 .await?;
         }
+        if old_interfaces.contains(Interface::Selection) {
+            self.unregister_interface::<SelectionInterface>(&path)
+                .await?;
+        }
         if old_interfaces.contains(Interface::Text) {
             self.unregister_interface::<TextInterface>(&path).await?;
         }
@@ -206,6 +217,7 @@ impl Bus {
             ObjectEvent::CaretMoved(_) => "TextCaretMoved",
             ObjectEvent::ChildAdded(_, _) | ObjectEvent::ChildRemoved(_) => "ChildrenChanged",
             ObjectEvent::PropertyChanged(_) => "PropertyChange",
+            ObjectEvent::SelectionChanged => "SelectionChanged",
             ObjectEvent::StateChanged(_, _) => "StateChanged",
             ObjectEvent::TextInserted { .. } | ObjectEvent::TextRemoved { .. } => "TextChanged",
             ObjectEvent::TextSelectionChanged => "TextSelectionChanged",
@@ -285,6 +297,10 @@ impl Bus {
                 };
                 self.emit_event(target, interface, signal, body).await
             }
+            ObjectEvent::SelectionChanged => {
+                self.emit_event(target, interface, signal, EventBodyBorrowed::default())
+                    .await
+            }
             ObjectEvent::StateChanged(state, value) => {
                 let mut body = EventBodyBorrowed::default();
                 body.kind = state.to_static_str();

platforms/unix/src/atspi/interfaces/mod.rs

@@ -7,6 +7,7 @@ mod accessible;
 mod action;
 mod application;
 mod component;
+mod selection;
 mod text;
 mod value;
 
@@ -31,5 +32,6 @@ pub(crate) use accessible::*;
 pub(crate) use action::*;
 pub(crate) use application::*;
 pub(crate) use component::*;
+pub(crate) use selection::*;
 pub(crate) use text::*;
 pub(crate) use value::*;

platforms/unix/src/atspi/interfaces/selection.rs

@@ -0,0 +1,82 @@
+// Copyright 2024 The AccessKit Authors. All rights reserved.
+// Licensed under the Apache License, Version 2.0 (found in
+// the LICENSE-APACHE file) or the MIT license (found in
+// the LICENSE-MIT file), at your option.
+
+use accesskit_atspi_common::PlatformNode;
+use zbus::{fdo, interface, names::OwnedUniqueName};
+
+use crate::atspi::{ObjectId, OwnedObjectAddress};
+
+pub(crate) struct SelectionInterface {
+    bus_name: OwnedUniqueName,
+    node: PlatformNode,
+}
+
+impl SelectionInterface {
+    pub fn new(bus_name: OwnedUniqueName, node: PlatformNode) -> Self {
+        Self { bus_name, node }
+    }
+
+    fn map_error(&self) -> impl '_ + FnOnce(accesskit_atspi_common::Error) -> fdo::Error {
+        |error| crate::util::map_error_from_node(&self.node, error)
+    }
+}
+
+#[interface(name = "org.a11y.atspi.Selection")]
+impl SelectionInterface {
+    #[zbus(property)]
+    fn n_selected_children(&self) -> fdo::Result<i32> {
+        self.node.n_selected_children().map_err(self.map_error())
+    }
+
+    fn get_selected_child(&self, selected_child_index: i32) -> fdo::Result<(OwnedObjectAddress,)> {
+        let child = self
+            .node
+            .selected_child(map_child_index(selected_child_index)?)
+            .map_err(self.map_error())?
+            .map(|child| ObjectId::Node {
+                adapter: self.node.adapter_id(),
+                node: child,
+            });
+        Ok(super::optional_object_address(&self.bus_name, child))
+    }
+
+    fn select_child(&self, child_index: i32) -> fdo::Result<bool> {
+        self.node
+            .select_child(map_child_index(child_index)?)
+            .map_err(self.map_error())
+    }
+
+    fn deselect_selected_child(&self, selected_child_index: i32) -> fdo::Result<bool> {
+        self.node
+            .deselect_selected_child(map_child_index(selected_child_index)?)
+            .map_err(self.map_error())
+    }
+
+    fn is_child_selected(&self, child_index: i32) -> fdo::Result<bool> {
+        self.node
+            .is_child_selected(map_child_index(child_index)?)
+            .map_err(self.map_error())
+    }
+
+    fn select_all(&self) -> fdo::Result<bool> {
+        self.node.select_all().map_err(self.map_error())
+    }
+
+    fn clear_selection(&self) -> fdo::Result<bool> {
+        self.node.clear_selection().map_err(self.map_error())
+    }
+
+    fn deselect_child(&self, child_index: i32) -> fdo::Result<bool> {
+        self.node
+            .deselect_child(map_child_index(child_index)?)
+            .map_err(self.map_error())
+    }
+}
+
+fn map_child_index(index: i32) -> fdo::Result<usize> {
+    index
+        .try_into()
+        .map_err(|_| fdo::Error::InvalidArgs("Index can't be negative.".into()))
+}