winit-core/window: add Window::request_ime_update

Allow updating IME state atomically to make it easier for platforms
where it's atomic by its nature, like Wayland. The old API is marked
as deprecated and is routed to the new atomic API.

Co-authored-by: dcz <gilapfco.dcz@porcupinefactory.org>

winit-appkit/src/view.rs

@@ -21,6 +21,7 @@ use winit_core::event::{
     PointerKind, PointerSource, TouchPhase, WindowEvent,
 };
 use winit_core::keyboard::{Key, KeyCode, KeyLocation, ModifiersState, NamedKey};
+use winit_core::window::ImeCapabilities;
 
 use super::app_state::AppState;
 use super::cursor::{default_cursor, invisible_cursor};
@@ -124,7 +125,7 @@ pub struct ViewState {
     /// True iff the application wants IME events.
     ///
     /// Can be set using `set_ime_allowed`
-    ime_allowed: Cell<bool>,
+    ime_capabilities: Cell<Option<ImeCapabilities>>,
 
     /// True if the current key event should be forwarded
     /// to the application, even during IME
@@ -456,7 +457,7 @@ define_class!(
             // we must send the `KeyboardInput` event during IME if it triggered
             // `doCommandBySelector`. (doCommandBySelector means that the keyboard input
             // is not handled by IME and should be handled by the application)
-            if self.ivars().ime_allowed.get() {
+            if self.ivars().ime_capabilities.get().is_some() {
                 let events_for_nsview = NSArray::from_slice(&[&*event]);
                 unsafe { self.interpretKeyEvents(&events_for_nsview) };
 
@@ -797,7 +798,7 @@ impl WinitView {
             tracking_rect: Default::default(),
             ime_state: Default::default(),
             input_source: Default::default(),
-            ime_allowed: Default::default(),
+            ime_capabilities: Default::default(),
             forward_key_to_app: Default::default(),
             marked_text: Default::default(),
             accepts_first_mouse,
@@ -859,12 +860,13 @@ impl WinitView {
         }
     }
 
-    pub(super) fn set_ime_allowed(&self, ime_allowed: bool) {
-        if self.ivars().ime_allowed.get() == ime_allowed {
+    pub(super) fn set_ime_allowed(&self, capabilities: Option<ImeCapabilities>) {
+        if self.ivars().ime_capabilities.get().is_some() {
             return;
         }
-        self.ivars().ime_allowed.set(ime_allowed);
-        if self.ivars().ime_allowed.get() {
+        self.ivars().ime_capabilities.set(capabilities);
+
+        if capabilities.is_some() {
             return;
         }
 
@@ -877,6 +879,10 @@ impl WinitView {
         }
     }
 
+    pub(super) fn ime_capabilities(&self) -> Option<ImeCapabilities> {
+        self.ivars().ime_capabilities.get()
+    }
+
     pub(super) fn set_ime_cursor_area(&self, position: NSPoint, size: NSSize) {
         self.ivars().ime_position.set(position);
         self.ivars().ime_size.set(size);