add flatten support for root elements (Enum and Structs)

yaserde/tests/ser_flatten.rs

@@ -0,0 +1,68 @@
+#[macro_use]
+extern crate yaserde_derive;
+
+use std::io::Write;
+use yaserde::ser::to_string;
+use yaserde::YaSerialize;
+
+macro_rules! convert_and_validate {
+  ($model: expr, $content: expr) => {
+    let data: Result<String, String> = to_string(&$model);
+    assert_eq!(
+      data,
+      Ok(
+        String::from($content)
+          .split("\n")
+          .map(|s| s.trim())
+          .collect::<String>()
+      )
+    );
+  };
+}
+
+#[test]
+fn ser_root_flatten_struct() {
+
+  #[derive(YaSerialize, PartialEq, Debug)]
+  #[yaserde(flatten)]
+  pub struct Content {
+    binary_data: String,
+    string_data: String,
+  }
+
+  let model = Content{
+    binary_data: "binary".to_string(),
+    string_data: "string".to_string(),
+  };
+  let content = r#"<?xml version="1.0" encoding="utf-8"?><binary_data>binary</binary_data><string_data>string</string_data>"#;
+  convert_and_validate!(model, content);
+}
+
+#[test]
+fn ser_root_flatten_enum() {
+  #[derive(YaSerialize, PartialEq, Debug)]
+  #[yaserde(flatten)]
+  pub enum Content {
+    Binary(Binary),
+    Data(Data),
+  }
+
+  #[derive(YaSerialize, PartialEq, Debug)]
+  pub struct Binary {
+    binary_data: String,
+  }
+
+  #[derive(YaSerialize, PartialEq, Debug)]
+  pub struct Data {
+    string_data: String,
+  }
+
+  let model = Content::Binary(Binary{binary_data: "binary".to_string()});
+  let content = r#"<?xml version="1.0" encoding="utf-8"?><Binary><binary_data>binary</binary_data></Binary>"#;
+  convert_and_validate!(model, content);
+
+
+  let model = Content::Data(Data{string_data: "string".to_string()});
+  let content = r#"<?xml version="1.0" encoding="utf-8"?><Data><string_data>string</string_data></Data>"#;
+  convert_and_validate!(model, content);
+}

yaserde_derive/src/ser/expand_enum.rs

@@ -1,7 +1,6 @@
 use crate::attribute::*;
 use crate::field_type::*;
 use proc_macro2::TokenStream;
-use std::collections::BTreeMap;
 use syn::spanned::Spanned;
 use syn::DataEnum;
 use syn::Fields;
@@ -11,8 +10,7 @@ pub fn serialize(
   data_enum: &DataEnum,
   name: &Ident,
   root: &str,
-  namespaces: &BTreeMap<String, String>,
-  default_namespace: &Option<String>,
+  root_attributes: &YaSerdeAttribute,
 ) -> TokenStream {
   let write_enum_content: TokenStream = data_enum
     .variants
@@ -224,10 +222,10 @@ pub fn serialize(
     .filter_map(|x| x)
     .collect();
 
-  let add_namespaces: TokenStream = namespaces
+  let add_namespaces: TokenStream = root_attributes.namespaces
     .iter()
     .map(|(prefix, namespace)| {
-      if let Some(dn) = default_namespace {
+      if let Some(dn) = &root_attributes.default_namespace {
         if dn == prefix {
           return Some(quote!(
             .default_ns(#namespace)
@@ -241,6 +239,8 @@ pub fn serialize(
     .filter_map(|x| x)
     .collect();
 
+  let flatten = root_attributes.flatten;
+
   quote! {
     use xml::writer::XmlEvent;
 
@@ -250,7 +250,7 @@ pub fn serialize(
         -> Result<(), String> {
         let skip = writer.skip_start_end();
 
-        if !skip {
+        if !#flatten && !skip {
           if let Some(label) = writer.get_start_event_name() {
             let struct_start_event = XmlEvent::start_element(label.as_ref());
             writer.write(struct_start_event).map_err(|e| e.to_string())?;
@@ -264,7 +264,7 @@ pub fn serialize(
           #write_enum_content
         }
 
-        if !skip {
+        if !#flatten && !skip {
           let struct_end_event = XmlEvent::end_element();
           writer.write(struct_end_event).map_err(|e| e.to_string())?;
         }

yaserde_derive/src/ser/expand_struct.rs

@@ -2,7 +2,6 @@ use crate::attribute::*;
 use crate::field_type::*;
 use crate::ser::element::*;
 use proc_macro2::TokenStream;
-use std::collections::BTreeMap;
 use std::string::ToString;
 use syn::spanned::Spanned;
 use syn::DataStruct;
@@ -12,8 +11,7 @@ pub fn serialize(
   data_struct: &DataStruct,
   name: &Ident,
   root: &str,
-  namespaces: &BTreeMap<String, String>,
-  default_namespace: &Option<String>,
+  root_attributes: &YaSerdeAttribute,
 ) -> TokenStream {
   let build_attributes: TokenStream = data_struct
     .fields
@@ -26,7 +24,7 @@ pub fn serialize(
 
       let label = &field.ident;
 
-      let label_name = build_label_name(&field, &field_attrs, default_namespace);
+      let label_name = build_label_name(&field, &field_attrs, &root_attributes.default_namespace);
 
       get_field_type(field).and_then(|f| match f {
         FieldType::FieldTypeString
@@ -205,10 +203,10 @@ pub fn serialize(
     .filter_map(|x| x)
     .collect();
 
-  let add_namespaces: TokenStream = namespaces
+  let add_namespaces: TokenStream = root_attributes.namespaces
     .iter()
     .map(|(prefix, namespace)| {
-      if let Some(dn) = default_namespace {
+      if let Some(dn) = &root_attributes.default_namespace {
         if dn == prefix {
           return Some(quote!(
             .default_ns(#namespace)
@@ -239,7 +237,7 @@ pub fn serialize(
         ));
       }
 
-      let label_name = build_label_name(&field, &field_attrs, default_namespace);
+      let label_name = build_label_name(&field, &field_attrs, &root_attributes.default_namespace);
       let conditions = condition_generator(label, &field_attrs);
 
       get_field_type(field).and_then(|f| match f {
@@ -381,6 +379,8 @@ pub fn serialize(
     .filter_map(|x| x)
     .collect();
 
+  let flatten = root_attributes.flatten;
+
   quote! {
     use xml::writer::XmlEvent;
 
@@ -390,7 +390,7 @@ pub fn serialize(
         -> Result<(), String> {
         let skip = writer.skip_start_end();
 
-        if !skip {
+        if !#flatten && !skip {
           let yaserde_label = writer.get_start_event_name().unwrap_or_else(|| #root.to_string());
           let struct_start_event = XmlEvent::start_element(yaserde_label.as_ref())#add_namespaces;
           #build_attributes
@@ -399,7 +399,7 @@ pub fn serialize(
 
         #struct_inspector
 
-        if !skip {
+        if !#flatten && !skip {
           let struct_end_event = XmlEvent::end_element();
           writer.write(struct_end_event).map_err(|e| e.to_string())?;
         }

yaserde_derive/src/ser/mod.rs

@@ -2,7 +2,7 @@ pub mod element;
 pub mod expand_enum;
 pub mod expand_struct;
 
-use crate::attribute;
+use crate::attribute::YaSerdeAttribute;
 use proc_macro2::TokenStream;
 use syn;
 use syn::Ident;
@@ -12,13 +12,13 @@ pub fn expand_derive_serialize(ast: &syn::DeriveInput) -> Result<TokenStream, St
   let attrs = &ast.attrs;
   let data = &ast.data;
 
-  let root_attrs = attribute::YaSerdeAttribute::parse(attrs);
+  let root_attrs = YaSerdeAttribute::parse(attrs);
   let root = root_attrs.clone().root.unwrap_or_else(|| name.to_string());
 
   let prefix = if root_attrs.default_namespace == root_attrs.prefix {
     "".to_string()
   } else {
-    root_attrs
+    root_attrs.clone()
       .prefix
       .map_or("".to_string(), |prefix| prefix + ":")
   };
@@ -30,15 +30,13 @@ pub fn expand_derive_serialize(ast: &syn::DeriveInput) -> Result<TokenStream, St
       data_struct,
       name,
       &root,
-      &root_attrs.namespaces,
-      &root_attrs.default_namespace,
+      &root_attrs,
     ),
     syn::Data::Enum(ref data_enum) => expand_enum::serialize(
       data_enum,
       name,
       &root,
-      &root_attrs.namespaces,
-      &root_attrs.default_namespace,
+      &root_attrs,
     ),
     syn::Data::Union(ref _data_union) => unimplemented!(),
   };