parsers: add starttls XSOs

parsers/src/starttls.rs

@@ -0,0 +1,68 @@
+// Copyright (c) 2018 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use xso::{AsXml, FromXml};
+
+use crate::ns;
+
+/// Request to start TLS.
+#[derive(FromXml, AsXml, PartialEq, Debug, Clone)]
+#[xml(namespace = ns::TLS, name = "starttls")]
+pub struct Request;
+
+/// Information that TLS may now commence.
+#[derive(FromXml, AsXml, PartialEq, Debug, Clone)]
+#[xml(namespace = ns::TLS, name = "proceed")]
+pub struct Proceed;
+
+/// Stream feature for StartTLS
+///
+/// Used in [`crate::stream_features::StreamFeatures`].
+#[derive(FromXml, AsXml, PartialEq, Debug, Clone)]
+#[xml(namespace = ns::TLS, name = "starttls")]
+pub struct StartTls {
+    /// Marker for mandatory StartTLS.
+    // TODO: replace with `#[xml(flag)]` once we have it
+    #[xml(child(default))]
+    pub required: Option<RequiredStartTls>,
+}
+
+/// Marker for mandatory StartTLS.
+#[derive(FromXml, AsXml, PartialEq, Debug, Clone)]
+#[xml(namespace = ns::TLS, name = "required")]
+pub struct RequiredStartTls;
+
+/// Enum which allows parsing/serialising any STARTTLS element.
+#[derive(FromXml, AsXml, Debug, Clone)]
+#[xml()]
+pub enum Nonza {
+    /// Request to start TLS
+    #[xml(transparent)]
+    Request(Request),
+
+    /// Information that TLS may now commence
+    #[xml(transparent)]
+    Proceed(Proceed),
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[cfg(target_pointer_width = "32")]
+    #[test]
+    fn test_size() {
+        assert_size!(RequiredStartTls, 0);
+        assert_size!(StartTls, 1);
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[test]
+    fn test_size() {
+        assert_size!(RequiredStartTls, 0);
+        assert_size!(StartTls, 1);
+    }
+}