use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
pub const SERVICE_NAME: &str = "com.apple.preboardservice_v2";
const MAX_PLIST_SIZE: usize = 4 * 1024 * 1024;
#[derive(Debug, thiserror::Error)]
pub enum PreboardError {
#[error("IO error: {0}")]
Io(#[from] std::io::Error),
#[error("plist error: {0}")]
Plist(String),
}
pub struct PreboardClient<S> {
stream: S,
}
impl<S: AsyncRead + AsyncWrite + Unpin> PreboardClient<S> {
pub fn new(stream: S) -> Self {
Self { stream }
}
pub async fn create_stashbag(
&mut self,
manifest: plist::Dictionary,
) -> Result<plist::Dictionary, PreboardError> {
self.send_command("CreateStashbag", manifest).await
}
pub async fn commit_stashbag(
&mut self,
manifest: plist::Dictionary,
) -> Result<plist::Dictionary, PreboardError> {
self.send_command("CommitStashbag", manifest).await
}
async fn send_command(
&mut self,
command: &str,
manifest: plist::Dictionary,
) -> Result<plist::Dictionary, PreboardError> {
let request = plist::Dictionary::from_iter([
(
"Command".to_string(),
plist::Value::String(command.to_string()),
),
("Manifest".to_string(), plist::Value::Dictionary(manifest)),
]);
send_plist(&mut self.stream, &plist::Value::Dictionary(request)).await?;
recv_plist(&mut self.stream).await
}
}
async fn send_plist<S: AsyncWrite + Unpin>(
stream: &mut S,
value: &plist::Value,
) -> Result<(), PreboardError> {
let mut buf = Vec::new();
plist::to_writer_xml(&mut buf, value).map_err(|e| PreboardError::Plist(e.to_string()))?;
stream.write_all(&(buf.len() as u32).to_be_bytes()).await?;
stream.write_all(&buf).await?;
stream.flush().await?;
Ok(())
}
async fn recv_plist<S: AsyncRead + Unpin>(
stream: &mut S,
) -> Result<plist::Dictionary, PreboardError> {
let mut len_buf = [0u8; 4];
stream.read_exact(&mut len_buf).await?;
let len = u32::from_be_bytes(len_buf) as usize;
if len > MAX_PLIST_SIZE {
return Err(PreboardError::Plist(format!(
"plist length {len} exceeds max {MAX_PLIST_SIZE}"
)));
}
let mut buf = vec![0u8; len];
stream.read_exact(&mut buf).await?;
plist::from_bytes(&buf).map_err(|e| PreboardError::Plist(e.to_string()))
}
#[cfg(test)]
mod tests {
use std::pin::Pin;
use std::task::{Context, Poll};
use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
use super::*;
struct MockStream {
read_buf: Vec<u8>,
written: Vec<u8>,
read_pos: usize,
}
impl MockStream {
fn with_response(value: plist::Value) -> Self {
let mut payload = Vec::new();
plist::to_writer_xml(&mut payload, &value).unwrap();
let mut read_buf = Vec::new();
read_buf.extend_from_slice(&(payload.len() as u32).to_be_bytes());
read_buf.extend_from_slice(&payload);
Self {
read_buf,
written: Vec::new(),
read_pos: 0,
}
}
}
impl AsyncRead for MockStream {
fn poll_read(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<std::io::Result<()>> {
let remaining = self.read_buf.len().saturating_sub(self.read_pos);
if remaining == 0 {
return Poll::Ready(Err(std::io::Error::new(
std::io::ErrorKind::UnexpectedEof,
"no more test data",
)));
}
let to_copy = remaining.min(buf.remaining());
let start = self.read_pos;
let end = start + to_copy;
buf.put_slice(&self.read_buf[start..end]);
self.read_pos = end;
Poll::Ready(Ok(()))
}
}
impl AsyncWrite for MockStream {
fn poll_write(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<std::io::Result<usize>> {
self.written.extend_from_slice(buf);
Poll::Ready(Ok(buf.len()))
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
Poll::Ready(Ok(()))
}
fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
Poll::Ready(Ok(()))
}
}
#[tokio::test]
async fn create_stashbag_sends_manifest() {
let response = plist::Value::Dictionary(plist::Dictionary::new());
let mut stream = MockStream::with_response(response);
let mut client = PreboardClient::new(&mut stream);
client
.create_stashbag(plist::Dictionary::from_iter([(
"Example".to_string(),
plist::Value::Boolean(true),
)]))
.await
.unwrap();
let len = u32::from_be_bytes(stream.written[..4].try_into().unwrap()) as usize;
let payload = &stream.written[4..4 + len];
let dict: plist::Dictionary = plist::from_bytes(payload).unwrap();
assert_eq!(dict["Command"].as_string(), Some("CreateStashbag"));
assert_eq!(
dict["Manifest"]
.as_dictionary()
.and_then(|m| m.get("Example"))
.and_then(plist::Value::as_boolean),
Some(true)
);
}
#[tokio::test]
async fn recv_plist_rejects_oversized_frame() {
let mut read_buf = ((MAX_PLIST_SIZE as u32) + 1).to_be_bytes().to_vec();
read_buf.extend_from_slice(b"ignored");
let mut stream = MockStream {
read_buf,
written: Vec::new(),
read_pos: 0,
};
let err = recv_plist(&mut stream).await.unwrap_err();
assert!(matches!(err, PreboardError::Plist(message) if message.contains("exceeds max")));
}
}