pin Connection

Due to the fact that we store a pointer to the Connection object inside
its own Handshake context, Connection objects cannot be moved (which is
why we return a boxed object from its constructor). Using Pin on it
makes the compiler enforce this.

Fixes #45.

README.md

@@ -207,7 +207,7 @@ be linked directly into C/C++ applications.
 Building
 --------
 
-quiche requires Rust 1.38 or later to build. The latest stable Rust release can
+quiche requires Rust 1.39 or later to build. The latest stable Rust release can
 be installed using [rustup](https://rustup.rs/).
 
 Once the Rust build environment is setup, the quiche source code can be fetched

examples/http3-server.rs

@@ -62,7 +62,7 @@ struct PartialResponse {
 }
 
 struct Client {
- conn: Box<quiche::Connection>,
+ conn: std::pin::Pin<Box<quiche::Connection>>,
 
  http3_conn: Option<quiche::h3::Connection>,
 
@@ -367,7 +367,7 @@ fn main() {
  loop {
  let http3_conn = client.http3_conn.as_mut().unwrap();
 
- match http3_conn.poll(client.conn.as_mut()) {
+ match http3_conn.poll(&mut client.conn) {
  Ok((
  stream_id,
  quiche::h3::Event::Headers { list, .. },

examples/server.rs

@@ -64,7 +64,7 @@ struct PartialResponse {
 }
 
 struct Client {
- conn: Box<quiche::Connection>,
+ conn: std::pin::Pin<Box<quiche::Connection>>,
 
  partial_responses: HashMap<u64, PartialResponse>,
 }

src/ffi.rs

@@ -296,7 +296,7 @@ pub extern fn quiche_accept(
  };
 
  match accept(scid, odcid, config) {
- Ok(c) => Box::into_raw(c),
+ Ok(c) => Box::into_raw(Pin::into_inner(c)),
 
  Err(_) => ptr::null_mut(),
  }
@@ -316,7 +316,7 @@ pub extern fn quiche_connect(
  let scid = unsafe { slice::from_raw_parts(scid, scid_len) };
 
  match connect(server_name, scid, config) {
- Ok(c) => Box::into_raw(c),
+ Ok(c) => Box::into_raw(Pin::into_inner(c)),
 
  Err(_) => ptr::null_mut(),
  }
@@ -373,7 +373,7 @@ pub extern fn quiche_conn_new_with_tls(
  let tls = unsafe { tls::Handshake::from_ptr(ssl) };
 
  match Connection::with_tls(scid, odcid, config, tls, is_server) {
- Ok(c) => Box::into_raw(c),
+ Ok(c) => Box::into_raw(Pin::into_inner(c)),
 
  Err(_) => ptr::null_mut(),
  }

src/lib.rs

@@ -239,6 +239,8 @@ extern crate log;
 use std::cmp;
 use std::time;
 
+use std::pin::Pin;
+
 /// The current QUIC wire version.
 pub const PROTOCOL_VERSION: u32 = 0xff00_0017;
 
@@ -771,7 +773,7 @@ pub struct Connection {
 /// ```
 pub fn accept(
  scid: &[u8], odcid: Option<&[u8]>, config: &mut Config,
-) -> Result<Box<Connection>> {
+) -> Result<Pin<Box<Connection>>> {
  let conn = Connection::new(scid, odcid, config, true)?;
 
  Ok(conn)
@@ -794,7 +796,7 @@ pub fn accept(
 /// ```
 pub fn connect(
  server_name: Option<&str>, scid: &[u8], config: &mut Config,
-) -> Result<Box<Connection>> {
+) -> Result<Pin<Box<Connection>>> {
  let conn = Connection::new(scid, None, config, false)?;
 
  if let Some(server_name) = server_name {
@@ -900,21 +902,21 @@ pub fn retry(
 impl Connection {
  fn new(
  scid: &[u8], odcid: Option<&[u8]>, config: &mut Config, is_server: bool,
- ) -> Result<Box<Connection>> {
+ ) -> Result<Pin<Box<Connection>>> {
  let tls = config.tls_ctx.new_handshake()?;
  Connection::with_tls(scid, odcid, config, tls, is_server)
  }
 
  fn with_tls(
  scid: &[u8], odcid: Option<&[u8]>, config: &mut Config,
  tls: tls::Handshake, is_server: bool,
- ) -> Result<Box<Connection>> {
+ ) -> Result<Pin<Box<Connection>>> {
  let max_rx_data = config.local_transport_params.initial_max_data;
 
  let scid_as_hex: Vec<String> =
  scid.iter().map(|b| format!("{:02x}", b)).collect();
 
- let mut conn = Box::new(Connection {
+ let mut conn = Box::pin(Connection {
  version: config.version,
 
  dcid: Vec::new(),
@@ -3167,8 +3169,8 @@ pub mod testing {
  use super::*;
 
  pub struct Pipe {
- pub client: Box<Connection>,
- pub server: Box<Connection>,
+ pub client: Pin<Box<Connection>>,
+ pub server: Pin<Box<Connection>>,
  }
 
  impl Pipe {