Add a ScancodeStream based on the SCANCODE_QUEUE

Cargo.lock

@@ -25,6 +25,7 @@ dependencies = [
  "bootloader",
  "conquer-once",
  "crossbeam-queue",
+ "futures-util",
  "lazy_static",
  "linked_list_allocator",
  "pc-keyboard",
@@ -86,6 +87,29 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "futures-core"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f25592f769825e89b92358db00d26f965761e094951ac44d3663ef25b7ac464a"
+
+[[package]]
+name = "futures-task"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b0a34e53cf6cdcd0178aa573aed466b646eb3db769570841fda0c7ede375a27"
+
+[[package]]
+name = "futures-util"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22766cf25d64306bedf0384da004d05c9974ab104fcc4528f1236181c18004c5"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "pin-utils",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -128,6 +152,12 @@ dependencies = [
  "cpuio",
 ]
 
+[[package]]
+name = "pin-utils"
+version = "0.1.0-alpha.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5894c618ce612a3fa23881b152b608bafb8c56cfc22f434a3ba3120b40f7b587"
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"

Cargo.toml

@@ -35,6 +35,11 @@ features = ["alloc"]
 version = "0.2.0"
 default-features = false
 
+[dependencies.futures-util]
+version = "0.3.4"
+default-features = false
+features = ["alloc"]
+
 [package.metadata.bootimage]
 test-args = [
     "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio",

src/task/keyboard.rs

@@ -1,6 +1,11 @@
 use crate::println;
 use conquer_once::spin::OnceCell;
+use core::{
+    pin::Pin,
+    task::{Context, Poll},
+};
 use crossbeam_queue::ArrayQueue;
+use futures_util::stream::Stream;
 
 static SCANCODE_QUEUE: OnceCell<ArrayQueue<u8>> = OnceCell::uninit();
 
@@ -16,3 +21,28 @@ pub(crate) fn add_scancode(scancode: u8) {
         println!("WARNING: scancode queue uninitialized");
     }
 }
+
+pub struct ScancodeStream {
+    _private: (),
+}
+
+impl ScancodeStream {
+    pub fn new() -> Self {
+        SCANCODE_QUEUE
+            .try_init_once(|| ArrayQueue::new(100))
+            .expect("ScancodeStream::new should only be called once");
+        ScancodeStream { _private: () }
+    }
+}
+
+impl Stream for ScancodeStream {
+    type Item = u8;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<u8>> {
+        let queue = SCANCODE_QUEUE.try_get().expect("not initialized");
+        match queue.pop() {
+            Ok(scancode) => Poll::Ready(Some(scancode)),
+            Err(crossbeam_queue::PopError) => Poll::Pending,
+        }
+    }
+}