Only use a single documentation popup (#1241)

helix-term/src/commands.rs

@@ -5130,9 +5130,13 @@ fn hover(cx: &mut Context) {
                 // skip if contents empty
 
                 let contents = ui::Markdown::new(contents, editor.syn_loader.clone());
-                let popup = Popup::new(contents);
+                let popup = Popup::new("documentation", contents);
+                if let Some(doc_popup) = compositor.find_id("documentation") {
+                    *doc_popup = popup;
+                } else {
                     compositor.push(Box::new(popup));
                 }
+            }
         },
     );
 }

helix-term/src/compositor.rs

@@ -64,6 +64,10 @@ pub trait Component: Any + AnyComponent {
     fn type_name(&self) -> &'static str {
         std::any::type_name::<Self>()
     }
+
+    fn id(&self) -> Option<&'static str> {
+        None
+    }
 }
 
 use anyhow::Error;
@@ -184,6 +188,14 @@ impl Compositor {
             .find(|component| component.type_name() == type_name)
             .and_then(|component| component.as_any_mut().downcast_mut())
     }
+
+    pub fn find_id<T: 'static>(&mut self, id: &'static str) -> Option<&mut T> {
+        let type_name = std::any::type_name::<T>();
+        self.layers
+            .iter_mut()
+            .find(|component| component.type_name() == type_name && component.id() == Some(id))
+            .and_then(|component| component.as_any_mut().downcast_mut())
+    }
 }
 
 // View casting, taken straight from Cursive

helix-term/src/ui/completion.rs

@@ -168,7 +168,7 @@ impl Completion {
                 }
             };
         });
-        let popup = Popup::new(menu);
+        let popup = Popup::new("completion", menu);
         let mut completion = Self {
             popup,
             start_offset,

helix-term/src/ui/popup.rs

@@ -16,15 +16,17 @@ pub struct Popup<T: Component> {
     position: Option<Position>,
     size: (u16, u16),
     scroll: usize,
+    id: &'static str,
 }
 
 impl<T: Component> Popup<T> {
-    pub fn new(contents: T) -> Self {
+    pub fn new(id: &'static str, contents: T) -> Self {
         Self {
             contents,
             position: None,
             size: (0, 0),
             scroll: 0,
+            id,
         }
     }
 
@@ -143,4 +145,8 @@ impl<T: Component> Component for Popup<T> {
 
         self.contents.render(area, surface, cx);
     }
+
+    fn id(&self) -> Option<&'static str> {
+        Some(self.id)
+    }
 }