feat(libkos): add fs, display, input service client modules with newtypes

crates/libkos/src/input.rs

@@ -0,0 +1,63 @@
+use types::bounded::CapSlot;
+use crate::syscall;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Key {
+    Up,
+    Down,
+    Left,
+    Right,
+    Enter,
+    Escape,
+    Space,
+    Backspace,
+    Tab,
+    Char(u8),
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum InputEvent {
+    KeyDown(Key),
+    KeyUp(Key),
+}
+
+fn decode_key(kind: usize, extra: usize) -> Option<Key> {
+    match kind {
+        0 => Some(Key::Up),
+        1 => Some(Key::Down),
+        2 => Some(Key::Left),
+        3 => Some(Key::Right),
+        4 => Some(Key::Enter),
+        5 => Some(Key::Escape),
+        6 => Some(Key::Space),
+        7 => Some(Key::Backspace),
+        8 => Some(Key::Tab),
+        9 => Some(Key::Char(extra as u8)),
+        _ => None,
+    }
+}
+
+pub fn poll_event(ep: CapSlot) -> Option<InputEvent> {
+    syscall::send(ep, 0, 0, 0, 0);
+    let (tag, kind, extra, _) = syscall::receive(ep);
+    match tag {
+        0 => None,
+        1 => decode_key(kind, extra).map(InputEvent::KeyDown),
+        2 => decode_key(kind, extra).map(InputEvent::KeyUp),
+        _ => None,
+    }
+}
+
+pub fn drain_events(ep: CapSlot) -> Option<InputEvent> {
+    let mut last = None;
+    loop {
+        match poll_event(ep) {
+            None => return last,
+            Some(ev) => {
+                if matches!(ev, InputEvent::KeyDown(_)) {
+                    last = Some(ev);
+                }
+            }
+        }
+    }
+}