From 05777be57026a90b91dcc7ffc624f48acc0e759a Mon Sep 17 00:00:00 2001
From: Alessandro Ghedini <alessandro@ghedini.me>
Date: Thu, 7 Nov 2019 15:02:01 +0000
Subject: [PATCH] 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                |  2 +-
 examples/http3-server.rs |  4 ++--
 examples/server.rs       |  2 +-
 src/ffi.rs               |  6 +++---
 src/lib.rs               | 16 +++++++++-------
 5 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index 3a28be24dc..6955b21818 100644
--- a/README.md
+++ b/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
diff --git a/examples/http3-server.rs b/examples/http3-server.rs
index c6f234aa70..2f17224679 100644
--- a/examples/http3-server.rs
+++ b/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, .. },
diff --git a/examples/server.rs b/examples/server.rs
index 692b02633d..2436fef391 100644
--- a/examples/server.rs
+++ b/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>,
 }
diff --git a/src/ffi.rs b/src/ffi.rs
index ba4f7ca4d4..d3df0923bd 100644
--- a/src/ffi.rs
+++ b/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(),
     }
diff --git a/src/lib.rs b/src/lib.rs
index fbd8879f53..e549ba4872 100644
--- a/src/lib.rs
+++ b/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 {
@@ -900,7 +902,7 @@ 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)
     }
@@ -908,13 +910,13 @@ impl Connection {
     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 {