add default variant
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Jean-Marie Mineau
parent
ae1c3e20ac
commit
7557022900
GPG key ID:
B66AEEDA9B645AD2
2 changed files with 240 additions and 21 deletions
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@ -17,7 +17,7 @@ use syn::{
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/// the type of the repeated data `D`, the type of the symbole at the end of the list `U`, and
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/// the specific value of the symbole at the end of the list `end`.
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///
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/// For example, we can deserialize a Vec<u8> until we find 0x0000:
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/// For example, we can deserialize a `Vec<u8>` until we find `0x0000`:
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///
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/// `[0, 1, 2, 3, 0, 0]` would be serialized as `vec![0, 1, 2, 3]`
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///
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@ -42,9 +42,57 @@ use syn::{
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/// );
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/// ```
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///
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/// ## Enum
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/// ## Enums
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///
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/// TODO
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/// Enums are a litle tricky.
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/// To distinguish the enum variant, there binary representation must be prefixed by
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/// the serialization of a specific type. This type is the same for the whole enum,
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/// and is defined with `prefix_type`, e.g. `#[prefix_type(u8)]`.
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///
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/// Each variant (except the default one) must define the prefix they match with `prefix`,
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/// e.g. `#[prefix(0x42)]`.
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///
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/// An enum can define ONE variant as the default variant. This variant is a catch all,
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/// and MUST be have named field or unnamed field (no unit variant!) and:
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/// - The first field of named fields variant must be named `prefix` and of the type
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/// `prefix_type`.
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/// - The first field of unnamed fields variant must be of the type `prefix_type`.
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///
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/// The first field of the default variant store the prefix of the variant.
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///
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/// ```
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/// pub use androscalpel_serializer::*;
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///
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/// #[derive(Serializable, PartialEq, Debug)]
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/// #[prefix_type(u8)]
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/// enum Example {
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/// #[prefix(0)]
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/// Zero,
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/// #[prefix(1)]
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/// One(u32),
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/// #[prefix(2)]
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/// Two { a: u16, b: u32 },
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/// #[default_variant]
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/// Dft(u8, u32)
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/// }
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///
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/// assert_eq!(
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/// Example::deserialize_from_slice(&[0u8]).unwrap(),
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/// Example::Zero
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/// );
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/// assert_eq!(
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/// Example::deserialize_from_slice(&[1u8, 0x01u8, 0x23u8, 0x45, 0x67]).unwrap(),
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/// Example::One(0x01234567)
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/// );
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/// assert_eq!(
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/// Example::deserialize_from_slice(&[2u8, 0xFEu8, 0xDCu8, 0x01u8, 0x23u8, 0x45, 0x67]).unwrap(),
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/// Example::Two { a: 0xFEDC, b: 0x01234567 }
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/// );
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/// assert_eq!(
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/// Example::deserialize_from_slice(&[42u8, 0x01u8, 0x23u8, 0x45, 0x67]).unwrap(),
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/// Example::Dft(42, 0x01234567)
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/// );
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/// ```
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///
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/// ## Prefix and suffix
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///
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@ -68,7 +116,7 @@ use syn::{
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/// ```
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///
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///
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#[proc_macro_derive(Serializable, attributes(until, prefix, prefix_type, suffix))]
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#[proc_macro_derive(Serializable, attributes(until, prefix, prefix_type, suffix, default_variant))]
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pub fn derive_serializable(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
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let input = parse_macro_input!(input as DeriveInput);
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let name = input.ident;
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@ -165,6 +213,7 @@ struct ParamsField {
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#[derive(Default)]
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struct ParamsVariant {
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pub prefix: Option<PrefixParamsVariant>,
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pub default_variant: Option<()>,
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}
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impl ParamsStruct {
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@ -224,6 +273,9 @@ impl ParamsVariant {
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Meta::List(MetaList { path, .. }) if path.is_ident("prefix_type") => {
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panic!("Variant cannot take the attribut 'prefix_type'")
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}
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Meta::Path(path) if path.is_ident("default_variant") => {
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params.default_variant = Some(());
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}
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_ => (),
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}
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}
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@ -327,10 +379,16 @@ fn get_implem_size(data: &Data, params: &ParamsStruct) -> TokenStream {
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let recurse = data.variants.iter().map(|v| {
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let ident = &v.ident;
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let params = ParamsVariant::parse(&v.attrs);
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let prefix = params.prefix.expect(
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"Cannot derive Serializable for variant without the #[prefix(val)] attribute",
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);
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let PrefixParamsVariant(val) = prefix;
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// let prefix = params.prefix.expect(
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// "Cannot derive Serializable for variant without the #[prefix(val)] attribute",
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// );
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// let PrefixParamsVariant(val) = prefix;
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let prefix_quote = match params {
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ParamsVariant {prefix: Some(PrefixParamsVariant(val)), default_variant: None } => quote_spanned! { v.span() => <#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) },
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ParamsVariant {prefix: None, default_variant: Some(()) } => quote! { 0 }, // The prefix is in the first field
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ParamsVariant {prefix: None, default_variant: None } => panic!("Cannot derive Serializable for variant without the #[prefix(val)] or #[default_variant] attribute"),
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ParamsVariant {prefix: Some(_), default_variant: Some(()) } => panic! ("A variant cannot be the default one and specify a prefix value"),
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};
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let match_ = get_enum_match(v);
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let body = match v.fields {
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Fields::Named(ref fields) => {
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@ -339,7 +397,8 @@ fn get_implem_size(data: &Data, params: &ParamsStruct) -> TokenStream {
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get_implem_size_for_field(f, quote! { *#name })
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});
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quote_spanned! { v.span() =>
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<#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) #(+#recurse )*
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//<#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) #(+#recurse )*
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#prefix_quote #(+#recurse )*
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}
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}
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Fields::Unnamed(ref fields) => {
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@ -348,10 +407,12 @@ fn get_implem_size(data: &Data, params: &ParamsStruct) -> TokenStream {
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get_implem_size_for_field(f, quote! { *#ident })
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});
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quote_spanned! { v.span() =>
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<#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) #(+#recurse )*
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//<#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) #(+#recurse )*
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#prefix_quote #(+#recurse )*
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}
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}
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Fields::Unit => quote! { <#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) },
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//Fields::Unit => quote! { <#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) },
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Fields::Unit => quote! { #prefix_quote },
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};
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quote_spanned! { v.span() =>
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@ -447,19 +508,40 @@ fn get_implem_serialize(data: &Data, params: &ParamsStruct) -> TokenStream {
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let recurse = data.variants.iter().map(|v| {
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let ident = &v.ident;
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let params = ParamsVariant::parse(&v.attrs);
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let prefix = params.prefix.expect(
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"Cannot derive Serializable for variant without the #[prefix(val)] attribute",
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);
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let PrefixParamsVariant(val) = prefix;
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//let prefix = params.prefix.expect(
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// "Cannot derive Serializable for variant without the #[prefix(val)] attribute",
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//);
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//let PrefixParamsVariant(val) = prefix;
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let prefix_quote = match params {
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ParamsVariant {prefix: Some(PrefixParamsVariant(val)), default_variant: None } => quote_spanned! { v.span() => <#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?; },
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ParamsVariant {prefix: None, default_variant: Some(()) } => quote! {},
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ParamsVariant {prefix: None, default_variant: None } => panic!("Cannot derive Serializable for variant without the #[prefix(val)] or #[default_variant] attribute"),
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ParamsVariant {prefix: Some(_), default_variant: Some(()) } => panic! ("A variant cannot be the default one and specify a prefix value"),
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};
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let match_ = get_enum_match(v);
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let body = match v.fields {
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Fields::Named(ref fields) => {
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if params.default_variant.is_some() && fields
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.named
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.first()
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.unwrap()
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.ident
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.as_ref()
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.expect(
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"Default variant must have a least one field for the prefix"
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) != "prefix" {
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panic!(
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"The first field of a named field variant must be named `prefix` and of the type of the prefix of the enum"
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);
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}
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let recurse = fields.named.iter().map(|f| {
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let name = &f.ident;
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get_implem_serialize_for_field(f, quote! { *#name })
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});
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quote_spanned! { v.span() =>
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<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
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//<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
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#prefix_quote
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#(#recurse)*
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}
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}
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@ -469,12 +551,14 @@ fn get_implem_serialize(data: &Data, params: &ParamsStruct) -> TokenStream {
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get_implem_serialize_for_field(f, quote! { *#ident })
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});
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quote_spanned! { v.span() =>
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<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
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//<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
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#prefix_quote
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#(#recurse)*
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}
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}
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Fields::Unit => quote! {
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<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
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//<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
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#prefix_quote
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},
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};
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@ -601,6 +685,10 @@ fn get_implem_deserialize(data: &Data, params: &ParamsStruct) -> TokenStream {
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let recurse = data.variants.iter().map(|v| {
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let v_ident = &v.ident;
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let v_params = ParamsVariant::parse(&v.attrs);
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// Serialization of default value at the end
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if v_params.default_variant.is_some() {
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return quote! {};
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}
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let PrefixParamsVariant(val) = v_params.prefix.expect(
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"Cannot derive Serializable for variant without the #[prefix(val)] attribute",
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);
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@ -634,13 +722,63 @@ fn get_implem_deserialize(data: &Data, params: &ParamsStruct) -> TokenStream {
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},
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}
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});
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let mut default_variant = None;
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for v in &data.variants {
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let v_params = ParamsVariant::parse(&v.attrs);
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if v_params.default_variant.is_some() && v_params.prefix.is_some() {
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panic!("A variant cannot be both the default variant and check a prefix value");
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}
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if v_params.default_variant.is_some() && default_variant.is_some() {
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panic!("An enum can only have one variant marked as `default_variant`");
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}
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if v_params.default_variant.is_some() {
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default_variant = Some(v);
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}
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}
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let default_quote = match default_variant {
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None => quote! {
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Err(androscalpel_serializer::Error::SerializationError(format!(
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"Found prefix {:?} that did not match any variant.", prefix
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)))
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},
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Some(v) => {
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let v_ident = &v.ident;
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match v.fields {
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Fields::Named(ref fields) => {
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// Skip 1 because the first field is the prefix
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// TODO: check first field name is `prefix`?
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let recurse = fields.named.iter().skip(1).map(|f| {
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let name = &f.ident;
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get_implem_deserialize_for_field(f, quote! { #name: })
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});
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quote_spanned! { v.span() =>
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return Ok(Self::#v_ident {prefix, #(#recurse)*});
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}
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}
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Fields::Unnamed(ref fields) => {
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let recurse = fields
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.unnamed
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.iter()
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.skip(1)
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.map(|f| get_implem_deserialize_for_field(f, quote! {}));
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quote_spanned! { v.span() =>
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return Ok(Self::#v_ident (prefix, #(#recurse)*));
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}
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}
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Fields::Unit => quote_spanned! { v.span() =>
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return Ok(Self::#v_ident);
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},
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}
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}
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};
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quote! {
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let prefix = <#prefix_ty as androscalpel_serializer::Serializable>::deserialize(input)?;
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#(#recurse)*
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Err(androscalpel_serializer::Error::SerializationError(format!(
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"Found prefix {:?} that did not match any variant.", prefix
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)))
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//Err(androscalpel_serializer::Error::SerializationError(format!(
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// "Found prefix {:?} that did not match any variant.", prefix
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//)))
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#default_quote
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}
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}
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Data::Union(_) => unimplemented!(),
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