Add Caps Lock support (#30470)

Closes #21700

Release Notes:

- Added caps lock support and show a warning if the user is entering an
SSH password with Caps Lock enabled

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: 张小白 <364772080@qq.com>

crates/gpui/src/platform/linux/x11/client.rs

@@ -1,3 +1,4 @@
+use crate::Capslock;
 use core::str;
 use std::{
     cell::RefCell,
@@ -203,8 +204,11 @@ pub struct X11ClientState {
     pub(crate) ximc: Option<X11rbClient<Rc<XCBConnection>>>,
     pub(crate) xim_handler: Option<XimHandler>,
     pub modifiers: Modifiers,
+    pub capslock: Capslock,
     // TODO: Can the other updates to `modifiers` be removed so that this is unnecessary?
+    // capslock logic was done analog to modifiers
     pub last_modifiers_changed_event: Modifiers,
+    pub last_capslock_changed_event: Capslock,
 
     pub(crate) compose_state: Option<xkbc::compose::State>,
     pub(crate) pre_edit_text: Option<String>,
@@ -473,7 +477,9 @@ impl X11Client {
 
         X11Client(Rc::new(RefCell::new(X11ClientState {
             modifiers: Modifiers::default(),
+            capslock: Capslock::default(),
             last_modifiers_changed_event: Modifiers::default(),
+            last_capslock_changed_event: Capslock::default(),
             event_loop: Some(event_loop),
             loop_handle: handle,
             common,
@@ -961,17 +967,25 @@ impl X11Client {
                 };
 
                 let modifiers = Modifiers::from_xkb(&state.xkb);
-                if state.last_modifiers_changed_event == modifiers {
+                let capslock = Capslock::from_xkb(&state.xkb);
+                if state.last_modifiers_changed_event == modifiers
+                    && state.last_capslock_changed_event == capslock
+                {
                     drop(state);
                 } else {
                     let focused_window_id = state.keyboard_focused_window?;
                     state.modifiers = modifiers;
                     state.last_modifiers_changed_event = modifiers;
+                    state.capslock = capslock;
+                    state.last_capslock_changed_event = capslock;
                     drop(state);
 
                     let focused_window = self.get_window(focused_window_id)?;
                     focused_window.handle_input(PlatformInput::ModifiersChanged(
-                        ModifiersChangedEvent { modifiers },
+                        ModifiersChangedEvent {
+                            modifiers,
+                            capslock,
+                        },
                     ));
                 }
 

crates/gpui/src/platform/linux/x11/window.rs

@@ -1215,6 +1215,17 @@ impl PlatformWindow for X11Window {
             .unwrap_or_default()
     }
 
+    fn capslock(&self) -> crate::Capslock {
+        self.0
+            .state
+            .borrow()
+            .client
+            .0
+            .upgrade()
+            .map(|ref_cell| ref_cell.borrow().capslock)
+            .unwrap_or_default()
+    }
+
     fn set_input_handler(&mut self, input_handler: PlatformInputHandler) {
         self.0.state.borrow_mut().input_handler = Some(input_handler);
     }