fix: Implement setting values on macOS (#615)

Author: httnn

platforms/macos/src/node.rs

@@ -23,8 +23,8 @@ use objc2::{
 };
 use objc2_app_kit::*;
 use objc2_foundation::{
-    ns_string, NSArray, NSCopying, NSInteger, NSNumber, NSObject, NSPoint, NSRange, NSRect,
-    NSString,
+    ns_string, NSArray, NSCopying, NSInteger, NSNumber, NSObject, NSObjectProtocol, NSPoint,
+    NSRange, NSRect, NSString,
 };
 use std::rc::{Rc, Weak};
 
@@ -357,6 +357,13 @@ impl NodeWrapper<'_> {
     }
 }
 
+// derived from objc2 0.6 `AnyObject::downcast_ref`
+// TODO: can be removed after updating objc2 to 0.6 which has `AnyObject::downcast_ref`
+fn downcast_ref<T: ClassType>(obj: &NSObject) -> Option<&T> {
+    obj.is_kind_of::<T>()
+        .then(|| unsafe { &*(obj as *const NSObject).cast::<T>() })
+}
+
 pub(crate) struct PlatformNodeIvars {
     context: Weak<Context>,
     node_id: NodeId,
@@ -548,9 +555,24 @@ declare_class!(
         }
 
         #[method(setAccessibilityValue:)]
-        fn set_value(&self, _value: &NSObject) {
-            // This isn't yet implemented. See the comment on this selector
-            // in `is_selector_allowed`.
+        fn set_value(&self, value: &NSObject) {
+            if let Some(string) = downcast_ref::<NSString>(value) {
+                self.resolve_with_context(|node, context| {
+                    context.do_action(ActionRequest {
+                        action: Action::SetValue,
+                        target: node.id(),
+                        data: Some(ActionData::Value(string.to_string().into())),
+                    });
+                });
+            } else if let Some(number) = downcast_ref::<NSNumber>(value) {
+                self.resolve_with_context(|node, context| {
+                    context.do_action(ActionRequest {
+                        action: Action::SetValue,
+                        target: node.id(),
+                        data: Some(ActionData::NumericValue(number.doubleValue())),
+                    });
+                });
+            }
         }
 
         #[method_id(accessibilityMinValue)]
@@ -1024,11 +1046,7 @@ declare_class!(
                     return node.supports_text_ranges();
                 }
                 if selector == sel!(setAccessibilityValue:) {
-                    // Our implementation of this currently does nothing,
-                    // and it's not clear if VoiceOver ever actually uses it,
-                    // but it must be allowed for editable text in order to get
-                    // the expected VoiceOver behavior.
-                    return node.supports_text_ranges() && !node.is_read_only();
+                    return (node.supports_text_ranges() && !node.is_read_only()) || node.supports_action(Action::SetValue, &filter);
                 }
                 if selector == sel!(isAccessibilitySelected) {
                     let wrapper = NodeWrapper(node);