Implement a ScancodeStream type

src/task/keyboard.rs

@@ -1,4 +1,47 @@
 use conquer_once::spin::OnceCell;
 use crossbeam_queue::ArrayQueue;
+use futures_util::stream::{Stream, StreamExt};
+use core::{pin::Pin, task::{Context, Poll}};
+use pc_keyboard::{layouts, DecodedKey, HandleControl, Keyboard, ScancodeSet1};
+use crate::print;
 
 static SCANCODE_QUEUE: OnceCell<ArrayQueue<u8>> = OnceCell::uninit();
+
+pub struct ScancodeStream;
+
+impl ScancodeStream {
+    pub fn new() -> Self {
+        SCANCODE_QUEUE.try_init_once(|| ArrayQueue::new(100))
+            .expect("ScancodeStream::new should only be called once");
+        ScancodeStream
+    }
+
+    pub async fn print_keypresses(mut self) {
+        let mut keyboard = Keyboard::new(layouts::Us104Key, ScancodeSet1, HandleControl::Ignore);
+
+        while let Some(scancode) = self.next().await {
+            if let Ok(Some(key_event)) = keyboard.add_byte(scancode) {
+                if let Some(key) = keyboard.process_keyevent(key_event) {
+                    match key {
+                        DecodedKey::Unicode(character) => print!("{}", character),
+                        DecodedKey::RawKey(key) => print!("{:?}", key),
+                    }
+                }
+            }
+        }
+    }
+}
+
+impl Stream for ScancodeStream {
+    type Item = u8;
+
+    fn poll_next(self: Pin<&mut Self>, context: &mut Context) -> Poll<Option<u8>> {
+        let queue = SCANCODE_QUEUE
+            .try_get()
+            .expect("scancode queue not initialized");
+        match queue.pop() {
+            Ok(scancode) => Poll::Ready(Some(scancode)),
+            Err(crossbeam_queue::PopError) => Poll::Pending,
+        }
+    }
+}