Add support for direct fields

instant-xml-macros/src/de.rs

@@ -196,9 +196,15 @@ fn deserialize_struct(
     // Common values
     let mut declare_values = TokenStream::new();
     let mut return_val = TokenStream::new();
+    let mut direct = TokenStream::new();
 
     let mut borrowed = BTreeSet::new();
     for (index, field) in fields.named.iter().enumerate() {
+        if !direct.is_empty() {
+            return syn::Error::new(field.span(), "direct field must be the last")
+                .into_compile_error();
+        }
+
         let field_meta = match FieldMeta::from_field(field, &container_meta) {
             Ok(meta) => meta,
             Err(err) => return err.into_compile_error(),
@@ -216,6 +222,7 @@ fn deserialize_struct(
             &mut return_val,
             tokens,
             &mut borrowed,
+            &mut direct,
             field_meta,
             &container_meta,
         );
@@ -299,6 +306,7 @@ fn deserialize_struct(
                                 }
                             }
                         }
+                        #direct
                         node => return Err(Error::UnexpectedNode(format!("{:?}", node))),
                     }
                 }
@@ -323,6 +331,7 @@ fn named_field(
     return_val: &mut TokenStream,
     tokens: &mut Tokens,
     borrowed: &mut BTreeSet<syn::Lifetime>,
+    direct: &mut TokenStream,
     mut field_meta: FieldMeta,
     container_meta: &ContainerMeta,
 ) -> Result<(), syn::Error> {
@@ -353,19 +362,21 @@ fn named_field(
     discard_lifetimes(&mut no_lifetime_type, borrowed, field_meta.borrow, true);
 
     let enum_name = Ident::new(&format!("__Value{index}"), Span::call_site());
-    tokens.r#enum.extend(quote!(#enum_name,));
+    if !field_meta.direct {
+        tokens.r#enum.extend(quote!(#enum_name,));
 
-    if !tokens.branches.is_empty() {
-        tokens.branches.extend(quote!(else));
+        if !tokens.branches.is_empty() {
+            tokens.branches.extend(quote!(else));
+        }
+        tokens.branches.extend(quote!(
+            if <#no_lifetime_type as FromXml>::KIND.matches(id, Id { ns: #ns, name: #field_tag })
+        ));
+
+        tokens.branches.extend(match field_meta.attribute {
+            true => quote!({ __Attributes::#enum_name }),
+            false => quote!({ __Elements::#enum_name }),
+        });
     }
-    tokens.branches.extend(quote!(
-        if <#no_lifetime_type as FromXml>::KIND.matches(id, Id { ns: #ns, name: #field_tag })
-    ));
-
-    tokens.branches.extend(match field_meta.attribute {
-        true => quote!({ __Attributes::#enum_name }),
-        false => quote!({ __Elements::#enum_name }),
-    });
 
     declare_values.extend(quote!(
         let mut #enum_name: Option<#no_lifetime_type> = None;
@@ -386,12 +397,26 @@ fn named_field(
 
     if !field_meta.attribute {
         if let Some(with) = deserialize_with {
+            if field_meta.direct {
+                return Err(syn::Error::new(
+                    field.span(),
+                    "direct attribute is not supported deserialization functions",
+                ));
+            }
+
             tokens.r#match.extend(quote!(
                 __Elements::#enum_name => {
                     let mut nested = deserializer.nested(data);
                     #with(&mut nested, &mut #enum_name)?;
                 },
             ));
+        } else if field_meta.direct {
+            direct.extend(quote!(
+                Node::Text(text) => {
+                    let mut nested = deserializer.for_node(Node::Text(text));
+                    FromXml::deserialize(&mut nested, &mut #enum_name)?;
+                }
+            ));
         } else {
             tokens.r#match.extend(quote!(
                 __Elements::#enum_name => match <#no_lifetime_type as FromXml>::KIND {
@@ -408,6 +433,13 @@ fn named_field(
             ));
         }
     } else {
+        if field_meta.direct {
+            return Err(syn::Error::new(
+                field.span(),
+                "direct attribute is not supported for attribute fields",
+            ));
+        }
+
         if let Some(with) = deserialize_with {
             tokens.r#match.extend(quote!(
                 __Attributes::#enum_name => {

instant-xml-macros/src/lib.rs

@@ -108,6 +108,7 @@ impl<'input> ContainerMeta<'input> {
 struct FieldMeta {
     attribute: bool,
     borrow: bool,
+    direct: bool,
     ns: NamespaceMeta,
     tag: TokenStream,
     serialize_with: Option<Literal>,
@@ -129,6 +130,7 @@ impl FieldMeta {
             match item {
                 MetaItem::Attribute => meta.attribute = true,
                 MetaItem::Borrow => meta.borrow = true,
+                MetaItem::Direct => meta.direct = true,
                 MetaItem::Ns(ns) => meta.ns = ns,
                 MetaItem::Rename(lit) => meta.tag = quote!(#lit),
                 MetaItem::SerializeWith(lit) => meta.serialize_with = Some(lit),

instant-xml-macros/src/meta.rs

@@ -295,6 +295,9 @@ pub(crate) fn meta_items(attrs: &[syn::Attribute]) -> Vec<(MetaItem, Span)> {
                 } else if id == "borrow" {
                     items.push((MetaItem::Borrow, span));
                     MetaState::Comma
+                } else if id == "direct" {
+                    items.push((MetaItem::Direct, span));
+                    MetaState::Comma
                 } else if id == "ns" {
                     MetaState::Ns
                 } else if id == "rename" {
@@ -477,6 +480,7 @@ impl fmt::Debug for Namespace {
 pub(crate) enum MetaItem {
     Attribute,
     Borrow,
+    Direct,
     Ns(NamespaceMeta),
     Rename(Literal),
     Mode(Mode),

instant-xml-macros/src/ser.rs

@@ -277,19 +277,6 @@ fn named_field(
         }
     };
 
-    if let Some(with) = field_meta.serialize_with {
-        let path = with.to_string();
-        let path = syn::parse_str::<syn::Path>(path.trim_matches('"')).map_err(|err| {
-            syn::Error::new(
-                with.span(),
-                format!("failed to parse serialize_with as path: {err}"),
-            )
-        })?;
-
-        body.extend(quote!(#path(&self.#field_name, serializer)?;));
-        return Ok(());
-    }
-
     let tag = field_meta.tag;
     let default_ns = match &meta.ns.uri {
         Some(ns) => quote!(#ns),
@@ -297,6 +284,13 @@ fn named_field(
     };
 
     if field_meta.attribute {
+        if field_meta.direct {
+            return Err(syn::Error::new(
+                field.span(),
+                "direct attribute is not supported on attributes",
+            ));
+        }
+
         let (ns, error) = match &field_meta.ns.uri {
             Some(Namespace::Path(path)) => match path.get_ident() {
                 Some(prefix) => match &meta.ns.prefixes.get(&prefix.to_string()) {
@@ -344,9 +338,33 @@ fn named_field(
 
     let mut no_lifetime_type = field.ty.clone();
     discard_lifetimes(&mut no_lifetime_type, borrowed, false, true);
-    body.extend(quote!(
-        self.#field_name.serialize(Some(::instant_xml::Id { ns: #ns, name: #tag }), serializer)?;
-    ));
+    if let Some(with) = field_meta.serialize_with {
+        if field_meta.direct {
+            return Err(syn::Error::new(
+                field.span(),
+                "direct serialization is not supported with `serialize_with`",
+            ));
+        }
+
+        let path = with.to_string();
+        let path = syn::parse_str::<syn::Path>(path.trim_matches('"')).map_err(|err| {
+            syn::Error::new(
+                with.span(),
+                format!("failed to parse serialize_with as path: {err}"),
+            )
+        })?;
+
+        body.extend(quote!(#path(&self.#field_name, serializer)?;));
+        return Ok(());
+    } else if field_meta.direct {
+        body.extend(quote!(
+            self.#field_name.serialize(None, serializer)?;
+        ));
+    } else {
+        body.extend(quote!(
+            self.#field_name.serialize(Some(::instant_xml::Id { ns: #ns, name: #tag }), serializer)?;
+        ));
+    }
 
     Ok(())
 }

instant-xml/tests/direct.rs

@@ -0,0 +1,23 @@
+use similar_asserts::assert_eq;
+
+use instant_xml::{from_str, to_string, FromXml, ToXml};
+
+#[derive(Debug, Eq, FromXml, PartialEq, ToXml)]
+struct Foo {
+    #[xml(attribute)]
+    flag: bool,
+    #[xml(direct)]
+    inner: String,
+}
+
+#[test]
+fn direct() {
+    let v = Foo {
+        flag: true,
+        inner: "hello".to_string(),
+    };
+    let xml = "<Foo flag=\"true\">hello</Foo>";
+
+    assert_eq!(to_string(&v).unwrap(), xml);
+    assert_eq!(from_str::<Foo>(xml), Ok(v));
+}