tls: update to std-future (#1224)

tokio-tls/examples/download-rust-lang.rs

@@ -1,32 +1,28 @@
-#![deny(warnings, rust_2018_idioms)]
+// #![deny(warnings, rust_2018_idioms)]
+#![feature(async_await)]
 
-use futures::Future;
 use native_tls::TlsConnector;
-use std::io;
+use std::error::Error;
 use std::net::ToSocketAddrs;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::TcpStream;
-use tokio::runtime::Runtime;
-use tokio_io;
 use tokio_tls;
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let runtime = Runtime::new()?;
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     let addr = "www.rust-lang.org:443"
         .to_socket_addrs()?
         .next()
         .ok_or("failed to resolve www.rust-lang.org")?;
 
-    let socket = TcpStream::connect(&addr);
+    let socket = TcpStream::connect(&addr).await?;
     let cx = TlsConnector::builder().build()?;
     let cx = tokio_tls::TlsConnector::from(cx);
 
-    let tls_handshake = socket.and_then(move |socket| {
-        cx.connect("www.rust-lang.org", socket)
-            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
-    });
-    let request = tls_handshake.and_then(|socket| {
-        tokio_io::io::write_all(
-            socket,
+    let mut socket = cx.connect("www.rust-lang.org", socket).await?;
+
+    socket
+        .write_all(
             "\
              GET / HTTP/1.0\r\n\
              Host: www.rust-lang.org\r\n\
@@ -34,10 +30,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
              "
             .as_bytes(),
         )
-    });
-    let response = request.and_then(|(socket, _)| tokio_io::io::read_to_end(socket, Vec::new()));
+        .await?;
 
-    let (_, data) = runtime.block_on(response)?;
-    println!("{}", String::from_utf8_lossy(&data));
+    let mut data = Vec::new();
+    socket.read_to_end(&mut data).await?;
+
+    // println!("data: {:?}", &data);
+    println!("{}", String::from_utf8_lossy(&data[..]));
     Ok(())
 }