feat(display): input routed via display server to focused app; input Subscribe; uses caps badged + Delegate

crates/servers/display-server/src/tests/focus.rs

@@ -0,0 +1,36 @@
+use crate::focus::Focus;
+
+const KEY: [usize; 4] = [1, 9, b'a' as usize, 0];
+
+#[test]
+fn only_the_app_in_focus_gets_events() {
+    let mut f: Focus<u8> = Focus::new();
+    assert_eq!(f.push(KEY), None, "nobody to give it to");
+    f.subscribe(1, 10);
+    assert_eq!(f.push(KEY), Some(10));
+    assert_eq!(f.poll(2), None);
+    assert_eq!(f.poll(1), Some(KEY));
+    assert_eq!(f.poll(1), None);
+}
+
+#[test]
+fn a_new_subscriber_takes_focus_and_the_old_queue_is_dropped() {
+    let mut f: Focus<u8> = Focus::new();
+    f.subscribe(1, 10);
+    f.push(KEY);
+    f.subscribe(2, 20);
+    assert_eq!(f.poll(1), None);
+    assert_eq!(f.poll(2), None);
+    assert_eq!(f.push(KEY), Some(20));
+    assert_eq!(f.poll(2), Some(KEY));
+}
+
+#[test]
+fn a_full_queue_drops_the_oldest() {
+    let mut f: Focus<u8> = Focus::new();
+    f.subscribe(1, 10);
+    for i in 0..40 {
+        f.push([1, 9, i, 0]);
+    }
+    assert_eq!(f.poll(1), Some([1, 9, 8, 0]));
+}

crates/servers/display-server/src/tests/mod.rs

@@ -1,2 +1,3 @@
+mod focus;
 mod protocol;
 mod server;