refactor: pass ALPN around as &str

src/net/tls.rs

@@ -8,7 +8,7 @@ use crate::net::session::SessionStream;
 pub async fn wrap_tls<'a>(
     strict_tls: bool,
     hostname: &str,
-    alpn: &[&str],
+    alpn: &str,
     stream: impl SessionStream + 'static,
 ) -> Result<impl SessionStream + 'a> {
     if strict_tls {
@@ -19,9 +19,14 @@ pub async fn wrap_tls<'a>(
         // We use native_tls because it accepts 1024-bit RSA keys.
         // Rustls does not support them even if
         // certificate checks are disabled: <https://github.com/rustls/rustls/issues/234>.
+        let alpns = if alpn.is_empty() {
+            Box::from([])
+        } else {
+            Box::from([alpn])
+        };
         let tls = async_native_tls::TlsConnector::new()
             .min_protocol_version(Some(async_native_tls::Protocol::Tlsv12))
-            .request_alpns(alpn)
+            .request_alpns(&alpns)
             .danger_accept_invalid_hostnames(true)
             .danger_accept_invalid_certs(true);
         let tls_stream = tls.connect(hostname, stream).await?;
@@ -32,7 +37,7 @@ pub async fn wrap_tls<'a>(
 
 pub async fn wrap_rustls<'a>(
     hostname: &str,
-    alpn: &[&str],
+    alpn: &str,
     stream: impl SessionStream + 'a,
 ) -> Result<impl SessionStream + 'a> {
     let mut root_cert_store = tokio_rustls::rustls::RootCertStore::empty();
@@ -41,7 +46,11 @@ pub async fn wrap_rustls<'a>(
     let mut config = tokio_rustls::rustls::ClientConfig::builder()
         .with_root_certificates(root_cert_store)
         .with_no_client_auth();
-    config.alpn_protocols = alpn.iter().map(|s| s.as_bytes().to_vec()).collect();
+    config.alpn_protocols = if alpn.is_empty() {
+        vec![]
+    } else {
+        vec![alpn.as_bytes().to_vec()]
+    };
 
     let tls = tokio_rustls::TlsConnector::from(Arc::new(config));
     let name = rustls_pki_types::ServerName::try_from(hostname)?.to_owned();