move gpui-components to ui crate

crates/ui/src/focusable.rs

@@ -0,0 +1,40 @@
+use gpui::{FocusHandle, ViewContext};
+
+/// A trait for views that can cycle focus between its children.
+///
+/// This will provide a default implementation for the `cycle_focus` method that will cycle focus.
+///
+/// You should implement the `cycle_focus_handles` method to return a list of focus handles that
+/// should be cycled, and the cycle will follow the order of the list.
+pub trait FocusableCycle {
+    /// Returns a list of focus handles that should be cycled.
+    fn cycle_focus_handles(&self, cx: &mut ViewContext<Self>) -> Vec<FocusHandle>
+    where
+        Self: Sized;
+
+    /// Cycles focus between the focus handles returned by `cycle_focus_handles`.
+    /// If `is_next` is `true`, it will cycle to the next focus handle, otherwise it will cycle to prev.
+    fn cycle_focus(&self, is_next: bool, cx: &mut ViewContext<Self>)
+    where
+        Self: Sized,
+    {
+        let focused_handle = cx.focused();
+        let handles = self.cycle_focus_handles(cx);
+        let handles = if is_next {
+            handles
+        } else {
+            handles.into_iter().rev().collect()
+        };
+
+        let fallback_handle = handles[0].clone();
+        let target_focus_handle = handles
+            .into_iter()
+            .skip_while(|handle| Some(handle) != focused_handle.as_ref())
+            .skip(1)
+            .next()
+            .unwrap_or(fallback_handle);
+
+        target_focus_handle.focus(cx);
+        cx.stop_propagation();
+    }
+}