Add MutableAppContext::keystrokes_for_action

This can be used to lookup keystrokes that will dispatch an action based on the currently focused view. There might be multiple, but we return the first found, meaning the most recently added bindings matching that action for the closest view to the focused view in the hierarchy.

crates/gpui/src/keymap.rs

@@ -30,9 +30,9 @@ pub struct Keymap {
 }
 
 pub struct Binding {
-    keystrokes: Vec<Keystroke>,
+    keystrokes: SmallVec<[Keystroke; 2]>,
     action: Box<dyn Action>,
-    context: Option<ContextPredicate>,
+    context_predicate: Option<ContextPredicate>,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]
@@ -146,7 +146,11 @@ impl Matcher {
         let mut retain_pending = false;
         for binding in self.keymap.bindings.iter().rev() {
             if binding.keystrokes.starts_with(&pending.keystrokes)
-                && binding.context.as_ref().map(|c| c.eval(cx)).unwrap_or(true)
+                && binding
+                    .context_predicate
+                    .as_ref()
+                    .map(|c| c.eval(cx))
+                    .unwrap_or(true)
             {
                 if binding.keystrokes.len() == pending.keystrokes.len() {
                     self.pending.remove(&view_id);
@@ -165,6 +169,24 @@ impl Matcher {
             MatchResult::None
         }
     }
+
+    pub fn keystrokes_for_action(
+        &self,
+        action: &dyn Action,
+        cx: &Context,
+    ) -> Option<SmallVec<[Keystroke; 2]>> {
+        for binding in self.keymap.bindings.iter().rev() {
+            if binding.action.id() == action.id()
+                && binding
+                    .context_predicate
+                    .as_ref()
+                    .map_or(true, |predicate| predicate.eval(cx))
+            {
+                return Some(binding.keystrokes.clone());
+            }
+        }
+        todo!()
+    }
 }
 
 impl Default for Matcher {
@@ -236,7 +258,7 @@ impl Binding {
         Ok(Self {
             keystrokes,
             action,
-            context,
+            context_predicate: context,
         })
     }