test-runner: Add example of using the Input protocol

uefi-test-runner/examples/input.rs

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#![no_main]
+#![no_std]
+
+use uefi::proto::console::text::{Input, Key, ScanCode};
+use uefi::{Result, ResultExt, Status, boot, entry, println, system};
+
+fn read_keyboard_events(input: &mut Input) -> Result {
+    loop {
+        println!("waiting for key press...");
+
+        // Pause until a keyboard event occurs.
+        let mut events = [input.wait_for_key_event().unwrap()];
+        boot::wait_for_event(&mut events).discard_errdata()?;
+
+        match input.read_key()? {
+            Some(Key::Printable(key)) => {
+                println!("key '{key}' was pressed");
+            }
+
+            // Exit the loop when the escape key is pressed.
+            Some(Key::Special(ScanCode::ESCAPE)) => {
+                break;
+            }
+            _ => {}
+        }
+    }
+
+    Ok(())
+}
+
+#[entry]
+fn main() -> Status {
+    system::with_stdin(|input| read_keyboard_events(input).status())
+}