implement Signature and Marshal for params::Variant

rustbus/src/params/types.rs

@@ -1,4 +1,4 @@
-use crate::signature;
+use crate::{signature, wire::marshal::traits::SignatureBuffer, Marshal, Signature, Unmarshal};
 
 /// The Types a message can have as parameters
 /// There are From<T> impls for most of the Base ones
@@ -213,3 +213,42 @@ impl<'a, 'e> Container<'a, 'e> {
         signature::Type::Container(sig)
     }
 }
+
+impl Signature for Variant<'_, '_> {
+    fn signature() -> signature::Type {
+        signature::Type::Container(signature::Container::Variant)
+    }
+    fn alignment() -> usize {
+        Variant::signature().get_alignment()
+    }
+    #[inline]
+    fn sig_str(s_buf: &mut SignatureBuffer) {
+        s_buf.push_static("v");
+    }
+    fn has_sig(sig: &str) -> bool {
+        sig.starts_with('v')
+    }
+}
+impl Marshal for Variant<'_, '_> {
+    fn marshal(
+        &self,
+        ctx: &mut crate::wire::marshal::MarshalContext,
+    ) -> Result<(), crate::wire::errors::MarshalError> {
+        let mut sig = String::new();
+        self.sig.to_str(&mut sig);
+        if sig.len() > 255 {
+            let sig_err = crate::signature::Error::SignatureTooLong;
+            return Err(sig_err.into());
+        }
+        debug_assert!(crate::params::validation::validate_signature(&sig).is_ok());
+        crate::wire::util::write_signature(&sig, ctx.buf);
+        crate::wire::marshal::container::marshal_param(&self.value, ctx)
+    }
+}
+impl<'buf, 'fds> Unmarshal<'buf, 'fds> for Variant<'buf, 'fds> {
+    fn unmarshal(
+        ctx: &mut crate::wire::unmarshal::UnmarshalContext<'fds, 'buf>,
+    ) -> crate::wire::unmarshal::UnmarshalResult<Self> {
+        crate::wire::unmarshal::container::unmarshal_variant(ctx)
+    }
+}

rustbus/src/tests/verify_marshalling.rs

@@ -296,4 +296,16 @@ fn verify_variant_marshalling() {
     // signature ++ padding ++ 32u8
     assert_eq!(ctx.buf, &[1, b'y', 0, 32]);
     ctx.buf.clear();
+
+    let param = crate::params::Param::Base(crate::params::Base::Byte(16));
+    let v = crate::params::Variant {
+        sig: crate::signature::Type::Base(crate::signature::Base::Byte),
+        value: param,
+    };
+
+    v.marshal(ctx).unwrap();
+
+    // signature ++ padding ++ 16u8
+    assert_eq!(ctx.buf, &[1, b'y', 0, 16]);
+    ctx.buf.clear();
 }