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EXPERIMENT: reference visitor
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as described in #1 (comment)
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@scottlamb
scottlamb committed Dec 15, 2021
1 parent ca51ec1 commit 7dc1737
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Showing 5 changed files with 181 additions and 288 deletions.
2 changes: 1 addition & 1 deletion static-xml-derive/src/common.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -477,7 +477,7 @@ impl<'a> ElementStruct<'a> {
.filter_map(|f| {
if matches!(f.mode, ElementFieldMode::Flatten) {
let ident = &f.inner.ident;
Some(quote_spanned! { f.inner.ident.span() => &mut self.#ident })
Some(quote_spanned! { f.inner.ident.span() => &mut self.out.#ident })
} else {
None
}
Expand Down
197 changes: 74 additions & 123 deletions static-xml-derive/src/deserialize.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,15 +13,14 @@ fn visitor_field_definitions(struct_: &ElementStruct) -> Vec<TokenStream> {
struct_
.fields
.iter()
.map(|field| {
let field_name = field.inner.ident.as_ref().unwrap();
let ty = &field.inner.ty;
.filter_map(|field| {
let span = field.inner.span();
let field_present = format_ident!("{}_present", &field.inner.ident.as_ref().unwrap());
match field.mode {
ElementFieldMode::Text => quote! { _text_buf: String },
_ => {
let trait_ = field.mode.quote_deserialize_trait();
quote_spanned! { field.inner.span() => #field_name: <#ty as #trait_>::Builder }
}
ElementFieldMode::Text => None,
_ => Some(quote_spanned! {span=>
#field_present: bool
}),
}
})
.collect()
Expand All @@ -31,52 +30,41 @@ fn visitor_initializers(struct_: &ElementStruct) -> Vec<TokenStream> {
struct_
.fields
.iter()
.map(|field| {
let field_name = field.inner.ident.as_ref().unwrap();
let ty = &field.inner.ty;
.filter_map(|field| {
let span = field.inner.span();
let field_present = format_ident!("{}_present", &field.inner.ident.as_ref().unwrap());
match field.mode {
ElementFieldMode::Text => quote! { _text_buf: String::new() },
_ => {
let trait_ = field.mode.quote_deserialize_trait();
quote_spanned! {
field.inner.span() => #field_name: <#ty as #trait_>::init()
}
}
ElementFieldMode::Text => None,
_ => Some(quote_spanned! {span=>
#field_present: false
}),
}
})
.collect()
}

fn value_fields_from_visitor(struct_: &ElementStruct) -> Vec<TokenStream> {
struct_.fields.iter().map(|field| {
let field_name = field.inner.ident.as_ref().unwrap();
fn finalize_visitor_fields(struct_: &ElementStruct) -> Vec<TokenStream> {
struct_.fields.iter().filter_map(|field| {
let span = field.inner.span();
let field_present = format_ident!("{}_present", &field.inner.ident.as_ref().unwrap());
let ty = &field.inner.ty;
let default = if field.default {
quote! { Some(Default::default) }
} else {
quote! { None }
};
match field.mode {
ElementFieldMode::Element { sorted_elements_pos: p } => {
quote_spanned! {
field.inner.span() => #field_name: <#ty as ::static_xml::de::DeserializeField>::finalize(self.#field_name, &ELEMENTS[#p], #default)?
}
}
ElementFieldMode::Attribute { sorted_attributes_pos: p } => {
quote_spanned! {
field.inner.span() => #field_name: <#ty as ::static_xml::de::DeserializeAttr>::finalize(self.#field_name, &ATTRIBUTES[#p], #default)?
}
}
ElementFieldMode::Flatten => {
quote_spanned! {
field.inner.span() => #field_name: <#ty as ::static_xml::de::DeserializeFlatten>::finalize(self.#field_name)?
}
ElementFieldMode::Element { sorted_elements_pos: p } if !field.default => {
Some(quote_spanned! {span=>
<#ty as ::static_xml::de::DeserializeField>::finalize(self.#field_present, &ELEMENTS[#p])?;
})
}
ElementFieldMode::Text => {
quote_spanned! {
field.inner.span() => #field_name: <#ty as ::static_xml::de::ParseText>::parse(self._text_buf)?
}
ElementFieldMode::Attribute { sorted_attributes_pos: p } if !field.default => {
Some(quote_spanned! {span=>
<#ty as ::static_xml::de::DeserializeAttr>::finalize(self.#field_present, &ATTRIBUTES[#p])?;
})
}
/*ElementFieldMode::Flatten if !field.default => {
Some(quote_spanned! {span=>
<#ty as ::static_xml::de::DeserializeFlatten>::finalize(self.#field_present)?;
})
}*/
_ => None
}
}).collect()
}
Expand Down Expand Up @@ -104,10 +92,11 @@ fn attribute_match_branches(struct_: &ElementStruct) -> Vec<TokenStream> {
.enumerate()
.map(|(i, &p)| {
let field = &struct_.fields[p];
let field_present = format_ident!("{}_present", &field.inner.ident.as_ref().unwrap());
let ident = field.inner.ident.as_ref().unwrap();
quote! {
Some(#i) => {
::static_xml::de::DeserializeAttrBuilder::attr(&mut self.#ident, name, value)?;
::static_xml::de::DeserializeAttr::attr(&mut self.out.#ident, &mut self.#field_present, name, value)?;
Ok(None)
}
}
Expand All @@ -122,11 +111,12 @@ fn element_match_branches(struct_: &ElementStruct) -> Vec<TokenStream> {
.enumerate()
.map(|(i, &p)| {
let field = &struct_.fields[p];
let field_present = format_ident!("{}_present", &field.inner.ident.as_ref().unwrap());
let ident = field.inner.ident.as_ref().unwrap();
let span = ident.span();
quote_spanned! {span=>
Some(#i) => {
::static_xml::de::DeserializeFieldBuilder::element(&mut self.#ident, child)?;
::static_xml::de::DeserializeField::element(&mut self.out.#ident, &mut self.#field_present, child)?;
return Ok(None)
}
}
Expand All @@ -142,67 +132,30 @@ fn do_struct(struct_: &ElementStruct) -> TokenStream {

let ident = &struct_.input.ident;
let (impl_generics, ty_generics, where_clause) = struct_.input.generics.split_for_impl();
let (visitor_type, visitor_defs, finalize, self_asserts);
if struct_.attr.direct {
visitor_type = struct_.input.ident.clone();
visitor_defs = struct_
.fields
.iter()
.filter_map(|f| {
let fident = f.inner.ident.as_ref().unwrap();
let span = fident.span();
let ty = &f.inner.ty;
let assert_ident = format_ident!("{}_{}_Assertion", ident, fident);
let trait_ = match f.mode {
ElementFieldMode::Attribute { .. } => {
quote! { ::static_xml::de::DeserializeAttrBuilder }
}
ElementFieldMode::Element { .. } => {
quote! { ::static_xml::de::DeserializeFieldBuilder }
}
_ => return None,
};
Some(quote_spanned! {span=>
// https://docs.rs/quote/1.0.10/quote/macro.quote_spanned.html#example
#[allow(non_camel_case_types)]
struct #assert_ident where #ty: #trait_;
})
})
.collect();
finalize = quote! { Ok(builder) };
let assert_ident = format_ident!("{}_Assertion", ident);
self_asserts = quote_spanned! {ident.span()=>
// https://docs.rs/quote/1.0.10/quote/macro.quote_spanned.html#example
#[allow(non_camel_case_types)]
struct #assert_ident where #ident: Default;
};
} else {
visitor_type = format_ident!("{}Visitor", &struct_.input.ident);
let visitor_field_definitions = visitor_field_definitions(&struct_);
let visitor_initializers = visitor_initializers(&struct_);
let value_fields_from_visitor = value_fields_from_visitor(&struct_);
visitor_defs = quote! {
pub struct #visitor_type {
#(#visitor_field_definitions, )*
};

impl Default for #visitor_type {
fn default() -> Self {
Self {
#(#visitor_initializers, )*
}
let visitor_type = format_ident!("{}Visitor", &struct_.input.ident);
let visitor_field_definitions = visitor_field_definitions(&struct_);
let visitor_initializers = visitor_initializers(&struct_);
let finalize_visitor_fields = finalize_visitor_fields(&struct_);
let visitor_defs = quote! {
pub struct #visitor_type<'out> {
out: &'out mut #ident,
#(#visitor_field_definitions, )*
}

impl<'out> #visitor_type<'out> {
fn new(out: &'out mut #ident) -> Self {
Self {
out,
#(#visitor_initializers, )*
}
}

impl #visitor_type {
fn finalize(self) -> Result<#ident, ::static_xml::de::VisitorError> {
Ok(#ident { #(#value_fields_from_visitor, )* })
}
fn finalize(self) -> Result<(), ::static_xml::de::VisitorError> {
#(#finalize_visitor_fields)*
Ok(())
}
};
finalize = quote! { builder.finalize() };
self_asserts = TokenStream::new();
}
}
};
let flatten_fields = struct_.quote_flatten_fields();
let (attribute_fallthrough, element_fallthrough);
if flatten_fields.is_empty() {
Expand Down Expand Up @@ -236,10 +189,9 @@ fn do_struct(struct_: &ElementStruct) -> TokenStream {
const ATTRIBUTES: &[::static_xml::ExpandedNameRef] = &[#(#attributes,)*];
const ELEMENTS: &[::static_xml::ExpandedNameRef] = &[#(#elements,)*];

#self_asserts;
#visitor_defs;
#visitor_defs

impl ::static_xml::de::ElementVisitor for #visitor_type {
impl<'out> ::static_xml::de::ElementVisitor for #visitor_type<'out> {
fn element<'a>(
&mut self,
child: ::static_xml::de::ElementReader<'a>,
Expand Down Expand Up @@ -269,13 +221,15 @@ fn do_struct(struct_: &ElementStruct) -> TokenStream {
fn deserialize(
element: ::static_xml::de::ElementReader<'_>,
) -> Result<Self, ::static_xml::de::VisitorError> {
let mut builder = #visitor_type::default();
let mut out = <#ident as Default>::default();
let mut builder = #visitor_type::new(&mut out);
element.read_to(&mut builder)?;
#finalize
builder.finalize()?;
Ok(out)
}
}

impl #impl_generics ::static_xml::de::DeserializeFlatten for #ident #ty_generics
/*impl #impl_generics ::static_xml::de::DeserializeFlatten for #ident #ty_generics
#where_clause {
type Builder = #visitor_type;
Expand All @@ -286,11 +240,11 @@ fn do_struct(struct_: &ElementStruct) -> TokenStream {
fn finalize(builder: Self::Builder) -> Result<Self, ::static_xml::de::VisitorError> {
#finalize
}
}
}*/
}
}

fn do_enum_indirect(enum_: &ElementEnum) -> TokenStream {
/*fn do_enum_indirect(enum_: &ElementEnum) -> TokenStream {
let ident = &enum_.input.ident;
let elements: Vec<_> = enum_
.variants
Expand Down Expand Up @@ -426,7 +380,7 @@ fn do_enum_indirect(enum_: &ElementEnum) -> TokenStream {
// can't derive DeserializeFlatten for Option<#ident> and Vec<#ident> because of the
// orphan rule. :-(
}
}
}*/

fn do_enum_direct(enum_: &ElementEnum) -> TokenStream {
let ident = &enum_.input.ident;
Expand All @@ -449,13 +403,10 @@ fn do_enum_direct(enum_: &ElementEnum) -> TokenStream {
Some(ty) => {
quote_spanned! {
vident.span() => Some(#i) => {
let mut builder = <#ty as ::static_xml::de::DeserializeField>::init();
::static_xml::de::DeserializeFieldBuilder::element(&mut builder, child)?;
*self = #ident::#vident(<#ty as ::static_xml::de::DeserializeField>::finalize(
builder,
&ELEMENTS[#i], // unused?
Some(|| unreachable!()),
)?);
let mut builder = <#ty as Default>::default();
let mut present = false;
::static_xml::de::DeserializeField::element(&mut builder, &mut present, child)?;
*self = #ident::#vident(builder);
}
}
}
Expand Down Expand Up @@ -506,11 +457,11 @@ pub(crate) fn derive(errors: &Errors, input: syn::DeriveInput) -> Result<TokenSt
match input.data {
Data::Enum(ref data) => {
let enum_ = ElementEnum::new(&errors, &input, data);
if enum_.attr.direct {
//if enum_.attr.direct {
Ok(do_enum_direct(&enum_))
} else {
Ok(do_enum_indirect(&enum_))
}
//} else {
// Ok(do_enum_indirect(&enum_))
//}
}
Data::Struct(ref data) => ElementStruct::new(&errors, &input, data).map(|s| do_struct(&s)),
_ => {
Expand Down
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