Fix namespace serialization of the Element type

xsd-parser-types/src/xml/element.rs

@@ -10,7 +10,7 @@ use quick_xml::{
     name::QName,
 };
 
-use crate::misc::format_utf8_slice;
+use crate::misc::{format_utf8_slice, Namespace, NamespacePrefix};
 
 #[cfg(feature = "quick-xml")]
 use crate::quick_xml::{
@@ -93,6 +93,29 @@ impl<'a> Element<'a> {
 
         self
     }
+
+    /// Add a namespace to the namespace context of this element.
+    ///
+    /// This will not add a namespace attribute to the element itself. It only
+    /// tells the serializer that this namespace must be valid in the context of
+    /// this element. If the namespace is not already declared in a parent element,
+    /// a suitable `xmlns` attribute will be added automatically.
+    ///
+    /// If you want to add a namespace declaration attribute to the element in
+    /// any case, use the [`Element::attribute`] method instead.
+    #[must_use]
+    pub fn namespace<P, N>(mut self, prefix: P, namespace: N) -> Self
+    where
+        P: Into<Cow<'a, [u8]>>,
+        N: Into<Cow<'a, [u8]>>,
+    {
+        let mut namespaces = self.namespaces.into_owned();
+        namespaces.insert(prefix.into().into(), namespace.into().into());
+
+        self.namespaces = namespaces.into_shared();
+
+        self
+    }
 }
 
 impl Debug for Element<'_> {
@@ -172,6 +195,7 @@ impl<'ser, 'el> ElementSerializer<'ser, 'el> {
         Self::Start { name, element }
     }
 
+    #[allow(clippy::too_many_lines)]
     fn next_item(&mut self, helper: &mut SerializeHelper) -> Result<Option<Event<'ser>>, Error> {
         loop {
             match replace(self, Self::Done) {
@@ -183,9 +207,19 @@ impl<'ser, 'el> ElementSerializer<'ser, 'el> {
                     });
 
                     let mut start = BytesStart::new(element_name);
+
+                    helper.begin_ns_scope();
+                    for (prefix, ns) in &**element.namespaces {
+                        let prefix = NamespacePrefix::new(prefix.0.clone().into_owned());
+                        let ns = Namespace::new(ns.0.clone().into_owned());
+                        helper.write_xmlns(&mut start, Some(&prefix), &ns);
+                    }
+
                     start.extend_attributes(attributes);
 
                     let event = if element.values.is_empty() {
+                        helper.end_ns_scope();
+
                         Event::Empty(start)
                     } else {
                         let values = element.values.iter();
@@ -206,6 +240,8 @@ impl<'ser, 'el> ElementSerializer<'ser, 'el> {
                     let end = BytesEnd::new(element_name);
                     let event = Event::End(end);
 
+                    helper.end_ns_scope();
+
                     return Ok(Some(event));
                 }
                 Self::NextValue {

xsd-parser-types/src/xml/namespaces.rs

@@ -12,12 +12,18 @@ use crate::misc::format_utf8_slice;
 #[derive(Default, Debug, Clone, Eq, PartialEq)]
 pub struct Namespaces<'a>(pub HashMap<Key<'a>, Value<'a>>);
 
-impl Namespaces<'_> {
+impl<'a> Namespaces<'a> {
     /// Create a new [`Namespaces`] instance.
     #[must_use]
     pub fn new() -> Self {
         Self::default()
     }
+
+    /// Convert this list into a shared version ([`NamespacesShared`]).
+    #[must_use]
+    pub fn into_shared(self) -> NamespacesShared<'a> {
+        NamespacesShared::new(self)
+    }
 }
 
 impl<'a> Deref for Namespaces<'a> {
@@ -81,6 +87,12 @@ impl<'a> From<&'a [u8]> for Key<'a> {
     }
 }
 
+impl<'a> From<Cow<'a, [u8]>> for Key<'a> {
+    fn from(value: Cow<'a, [u8]>) -> Self {
+        Self(value)
+    }
+}
+
 impl Deref for Key<'_> {
     type Target = [u8];
 
@@ -146,6 +158,24 @@ impl Borrow<[u8]> for Value<'_> {
     }
 }
 
+impl From<Vec<u8>> for Value<'static> {
+    fn from(value: Vec<u8>) -> Self {
+        Self(Cow::Owned(value))
+    }
+}
+
+impl<'a> From<&'a [u8]> for Value<'a> {
+    fn from(value: &'a [u8]) -> Self {
+        Self(Cow::Borrowed(value))
+    }
+}
+
+impl<'a> From<Cow<'a, [u8]>> for Value<'a> {
+    fn from(value: Cow<'a, [u8]>) -> Self {
+        Self(value)
+    }
+}
+
 /// Represents a shared list of namespaces.
 ///
 /// This is useful to not store the same map again and again. Is uses an [`Arc`]

xsd-parser/tests/feature/any/example/default.xml

@@ -6,7 +6,7 @@
     <tns:Name>def</tns:Name>
   </tns:Choice>
   <tns:Choice>
-    <AnyElement2 />
+    <AnyElement2 xmlns:anyNs="http://example.com/anyNs" />
   </tns:Choice>
   <tns:Choice>
     <AnotherElement2 />

xsd-parser/tests/feature/any/mod.rs

@@ -80,7 +80,12 @@ macro_rules! test_obj {
                 },
                 ChoiceType {
                     any_attribute: AnyAttributes::default(),
-                    content: ChoiceTypeContent::Any(Element::default().name(b"AnyElement2")),
+                    content: ChoiceTypeContent::Any(
+                        Element::default()
+                            .name(b"AnyElement2")
+                            .namespace(b"tns", b"http://example.com")
+                            .namespace(b"anyNs", b"http://example.com/anyNs"),
+                    ),
                 },
                 ChoiceType {
                     any_attribute: AnyAttributes::default(),