Adjust the type arrangement on ManagedViews (#3354)

Made the trait into a blanket-trait impl if you have it's two
constituent pieces (FocusableView and EventEmitter) to remove the
duplicated method. I also changed the struct to an enum for aesthetic
reasons (EventType::EventName feels self documenting to me) and added
some new `cx` APIs utilizing our new powers of dismissal.

Release Notes:

- N/A

crates/gpui2/src/app/async_context.rs

@@ -1,6 +1,6 @@
 use crate::{
     AnyView, AnyWindowHandle, AppCell, AppContext, BackgroundExecutor, Context, FocusableView,
-    ForegroundExecutor, Model, ModelContext, Render, Result, Task, View, ViewContext,
+    ForegroundExecutor, Manager, Model, ModelContext, Render, Result, Task, View, ViewContext,
     VisualContext, WindowContext, WindowHandle,
 };
 use anyhow::{anyhow, Context as _};
@@ -320,4 +320,13 @@ impl VisualContext for AsyncWindowContext {
             view.read(cx).focus_handle(cx).clone().focus(cx);
         })
     }
+
+    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
+    where
+        V: crate::ManagedView,
+    {
+        self.window.update(self, |_, cx| {
+            view.update(cx, |_, cx| cx.emit(Manager::Dismiss))
+        })
+    }
 }

crates/gpui2/src/app/test_context.rs

@@ -579,6 +579,17 @@ impl<'a> VisualContext for VisualTestContext<'a> {
             })
             .unwrap()
     }
+
+    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
+    where
+        V: crate::ManagedView,
+    {
+        self.window
+            .update(self.cx, |_, cx| {
+                view.update(cx, |_, cx| cx.emit(crate::Manager::Dismiss))
+            })
+            .unwrap()
+    }
 }
 
 impl AnyWindowHandle {

crates/gpui2/src/gpui2.rs

@@ -141,6 +141,10 @@ pub trait VisualContext: Context {
     fn focus_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
     where
         V: FocusableView;
+
+    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
+    where
+        V: ManagedView;
 }
 
 pub trait Entity<T>: Sealed {

crates/gpui2/src/window.rs

@@ -193,17 +193,12 @@ pub trait FocusableView: Render {
 
 /// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 /// where the lifecycle of the view is handled by another view.
-pub trait ManagedView: Render {
-    fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
-}
+pub trait ManagedView: FocusableView + EventEmitter<Manager> {}
 
-pub struct Dismiss;
-impl<T: ManagedView> EventEmitter<Dismiss> for T {}
+impl<M: FocusableView + EventEmitter<Manager>> ManagedView for M {}
 
-impl<T: ManagedView> FocusableView for T {
-    fn focus_handle(&self, cx: &AppContext) -> FocusHandle {
-        self.focus_handle(cx)
-    }
+pub enum Manager {
+    Dismiss,
 }
 
 // Holds the state for a specific window.
@@ -1582,6 +1577,13 @@ impl VisualContext for WindowContext<'_> {
             view.focus_handle(cx).clone().focus(cx);
         })
     }
+
+    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
+    where
+        V: ManagedView,
+    {
+        self.update_view(view, |_, cx| cx.emit(Manager::Dismiss))
+    }
 }
 
 impl<'a> std::ops::Deref for WindowContext<'a> {
@@ -2275,6 +2277,13 @@ impl<'a, V: 'static> ViewContext<'a, V> {
     {
         self.defer(|view, cx| view.focus_handle(cx).focus(cx))
     }
+
+    pub fn dismiss_self(&mut self)
+    where
+        V: ManagedView,
+    {
+        self.defer(|_, cx| cx.emit(Manager::Dismiss))
+    }
 }
 
 impl<V> Context for ViewContext<'_, V> {
@@ -2354,6 +2363,10 @@ impl<V: 'static> VisualContext for ViewContext<'_, V> {
     fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
         self.window_cx.focus_view(view)
     }
+
+    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
+        self.window_cx.dismiss_view(view)
+    }
 }
 
 impl<'a, V> std::ops::Deref for ViewContext<'a, V> {