androscalpel/androscalpel_serializer_derive/src/lib.rs
2023-12-12 11:25:33 +01:00

790 lines
31 KiB
Rust

use proc_macro2::TokenStream;
use quote::{format_ident, quote, quote_spanned};
use syn::parse::{Parse, ParseStream};
use syn::spanned::Spanned;
use syn::{
parse_macro_input, Attribute, Data, DeriveInput, Field, Fields, Ident, Index, Meta, MetaList,
Token, Type, Variant,
};
/// Derive the type Serializable.
///
/// For simple case, it is just a concatenation of the Serializable fields.
///
/// ## Until
///
/// For list of data, we can serialize data until we find some specific data. To do so we need
/// the type of the repeated data `D`, the type of the symbole at the end of the list `U`, and
/// the specific value of the symbole at the end of the list `end`.
///
/// For example, we can deserialize a `Vec<u8>` until we find `0x0000`:
///
/// `[0, 1, 2, 3, 0, 0]` would be serialized as `vec![0, 1, 2, 3]`
///
/// In this example, `D` is `u8`, `U` is `u16` and `end` is `0x0000`.
///
/// To define a field using this method, the type of field must implement the trait
/// `SerializableUntil<D, U>`, `D` and `U` must implement `Serializable`, and the field
/// must be marked with the attribute `#[until(D, U, end)]`:
///
/// ```
/// pub use androscalpel_serializer::*;
///
/// #[derive(Serializable, PartialEq, Debug)]
/// struct Example {
/// #[until(u8, u16, 0)]
/// a: Vec<u8>,
/// }
///
/// assert_eq!(
/// Example::deserialize_from_slice(&[0, 1, 2, 3, 0, 0]).unwrap(),
/// Example { a: vec![0, 1, 2, 3] }
/// );
/// ```
///
/// ## Enums
///
/// Enums are a litle tricky.
/// To distinguish the enum variant, there binary representation must be prefixed by
/// the serialization of a specific type. This type is the same for the whole enum,
/// and is defined with `prefix_type`, e.g. `#[prefix_type(u8)]`.
///
/// Each variant (except the default one) must define the prefix they match with `prefix`,
/// e.g. `#[prefix(0x42)]`.
///
/// An enum can define ONE variant as the default variant. This variant is a catch all,
/// and MUST be have named field or unnamed field (no unit variant!) and:
/// - The first field of named fields variant must be named `prefix` and of the type
/// `prefix_type`.
/// - The first field of unnamed fields variant must be of the type `prefix_type`.
///
/// The first field of the default variant store the prefix of the variant.
///
/// ```
/// pub use androscalpel_serializer::*;
///
/// #[derive(Serializable, PartialEq, Debug)]
/// #[prefix_type(u8)]
/// enum Example {
/// #[prefix(0)]
/// Zero,
/// #[prefix(1)]
/// One(u32),
/// #[prefix(2)]
/// Two { a: u16, b: u32 },
/// #[default_variant]
/// Dft(u8, u32)
/// }
///
/// assert_eq!(
/// Example::deserialize_from_slice(&[0u8]).unwrap(),
/// Example::Zero
/// );
/// assert_eq!(
/// Example::deserialize_from_slice(&[1u8, 0x67, 0x45, 0x23u8, 0x01u8]).unwrap(),
/// Example::One(0x01234567)
/// );
/// assert_eq!(
/// Example::deserialize_from_slice(&[2u8, 0xDCu8, 0xFEu8, 0x67, 0x45, 0x23u8, 0x01u8]).unwrap(),
/// Example::Two { a: 0xFEDC, b: 0x01234567 }
/// );
/// assert_eq!(
/// Example::deserialize_from_slice(&[42u8, 0x67, 0x45, 0x23u8, 0x01u8]).unwrap(),
/// Example::Dft(42, 0x01234567)
/// );
/// ```
///
/// ## Prefix and suffix
///
/// To define a constant prefix before a serialised field or suffixe after, use `#[prefix(<prefix>)]`
/// and `#[suffix(<suffix>)]`. The prefix/suffix must be `u8`s `Iterator`.
///
/// ```
/// pub use androscalpel_serializer::*;
///
/// #[derive(Serializable, PartialEq, Debug)]
/// struct Example {
/// #[prefix([0x42])]
/// #[suffix([0x66, 0x66])]
/// a: u32,
/// }
///
/// assert_eq!(
/// Example::deserialize_from_slice(&[0x42, 3, 2, 1, 0, 0x66, 0x66]).unwrap(),
/// Example { a: 0x00010203 }
/// );
/// ```
///
///
#[proc_macro_derive(
Serializable,
attributes(until, prefix, prefix_type, suffix, default_variant)
)]
pub fn derive_serializable(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = input.ident;
let params = ParamsStruct::parse(&input.attrs);
let implem_serialize = get_implem_serialize(&input.data, &params);
let implem_deserialize = get_implem_deserialize(&input.data, &params);
let implem_size = get_implem_size(&input.data, &params);
let expanded = quote! {
impl androscalpel_serializer::Serializable for #name {
#[allow(clippy::single_element_loop, clippy::let_and_return)]
fn serialize(&self, output: &mut dyn std::io::Write) -> androscalpel_serializer::Result<()> {
#implem_serialize
}
#[allow(clippy::single_element_loop, clippy::let_and_return, clippy::needless_return)]
fn deserialize(input: &mut dyn androscalpel_serializer::ReadSeek) -> androscalpel_serializer::Result<Self> {
#implem_deserialize
}
#[allow(clippy::identity_op)]
fn size(&self) -> usize {
#implem_size
}
}
};
proc_macro::TokenStream::from(expanded)
}
/// Parsed Parameters for the `#[until(D, U, end)]` attribute.
/// `D` is the type of the repeated data, `U` is the type of `end`,
/// `end` is the object that mark the end of the repetition of `U`s.
struct UntilParams(Ident, Ident, TokenStream);
impl Parse for UntilParams {
fn parse(input: ParseStream) -> syn::Result<Self> {
let data_type = input.parse()?;
input.parse::<Token![,]>()?;
let end_type = input.parse()?;
input.parse::<Token![,]>()?;
let until = input.parse()?;
Ok(Self(data_type, end_type, until))
}
}
/// Parsed Parameters for the `#[prefix(val)]` attribute of an enum variant.
struct PrefixParamsVariant(TokenStream);
impl Parse for PrefixParamsVariant {
fn parse(input: ParseStream) -> syn::Result<Self> {
let value = input.parse()?;
Ok(Self(value))
}
}
/// Parsed Parameters for the `#[prefix_type(T)]` attribute.
struct PrefixTypeParams(TokenStream);
impl Parse for PrefixTypeParams {
fn parse(input: ParseStream) -> syn::Result<Self> {
let data_type = input.parse()?;
Ok(Self(data_type))
}
}
/// All the attributes parameters for a struct/enum
#[derive(Default)]
struct ParamsStruct {
pub prefix_type: Option<PrefixTypeParams>,
}
/// Parsed Parameters for the `#[prefix(val)]` attribute of an struct field.
struct PrefixParamsField(TokenStream);
impl Parse for PrefixParamsField {
fn parse(input: ParseStream) -> syn::Result<Self> {
let value = input.parse()?;
Ok(Self(value))
}
}
/// Parsed Parameters for the `#[suffix(val)]` attribute of an struct field.
struct SuffixParamsField(TokenStream);
impl Parse for SuffixParamsField {
fn parse(input: ParseStream) -> syn::Result<Self> {
let value = input.parse()?;
Ok(Self(value))
}
}
/// All the attributes parameters for a field
#[derive(Default)]
struct ParamsField {
pub until: Option<UntilParams>,
pub prefix: Option<PrefixParamsField>,
pub suffix: Option<SuffixParamsField>,
}
/// All the attributes parameters for a variant
#[derive(Default)]
struct ParamsVariant {
pub prefix: Option<PrefixParamsVariant>,
pub default_variant: Option<()>,
}
impl ParamsStruct {
fn parse(attrs: &[Attribute]) -> Self {
let mut params = ParamsStruct::default();
for attr in attrs {
match &attr.meta {
Meta::List(MetaList { path, .. }) if path.is_ident("until") => {
panic!("Structur/Enum cannot take the attribut 'until'")
}
Meta::List(MetaList { path, .. }) if path.is_ident("prefix") => {
panic!("Structur/Enum cannot take the attribut 'prefix'")
}
Meta::List(MetaList { path, tokens, .. }) if path.is_ident("prefix_type") => {
params.prefix_type = Some(syn::parse2(tokens.clone()).unwrap());
}
_ => (),
}
}
params
}
}
impl ParamsField {
fn parse(attrs: &[Attribute]) -> Self {
let mut params = ParamsField::default();
for attr in attrs {
match &attr.meta {
Meta::List(MetaList { path, tokens, .. }) if path.is_ident("until") => {
params.until = Some(syn::parse2(tokens.clone()).unwrap())
}
Meta::List(MetaList { path, tokens, .. }) if path.is_ident("prefix") => {
params.prefix = Some(syn::parse2(tokens.clone()).unwrap())
}
Meta::List(MetaList { path, tokens, .. }) if path.is_ident("suffix") => {
params.suffix = Some(syn::parse2(tokens.clone()).unwrap())
}
Meta::List(MetaList { path, .. }) if path.is_ident("prefix_type") => {
panic!("Fields cannot take the attribut 'prefix_type'")
}
_ => (),
}
}
params
}
}
impl ParamsVariant {
fn parse(attrs: &[Attribute]) -> Self {
let mut params = ParamsVariant::default();
for attr in attrs {
match &attr.meta {
Meta::List(MetaList { path, .. }) if path.is_ident("until") => {
panic!("Variant cannot take the attribut 'until'")
}
Meta::List(MetaList { path, tokens, .. }) if path.is_ident("prefix") => {
params.prefix = Some(syn::parse2(tokens.clone()).unwrap());
}
Meta::List(MetaList { path, .. }) if path.is_ident("prefix_type") => {
panic!("Variant cannot take the attribut 'prefix_type'")
}
Meta::Path(path) if path.is_ident("default_variant") => {
params.default_variant = Some(());
}
_ => (),
}
}
params
}
}
/// Return the match statement an enum variant.
fn get_enum_match(variant: &Variant) -> TokenStream {
match variant.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
quote! { #name }
});
quote_spanned! { variant.span() =>
{#(#recurse,)*}
}
}
Fields::Unnamed(ref fields) => {
let names: Vec<_> = fields
.unnamed
.iter()
.enumerate()
.map(|(i, _)| format_ident!("field{}", i))
.collect();
quote_spanned! { variant.span() =>
(#(#names,)*)
}
}
Fields::Unit => quote! {},
}
}
/// Return the implementation of the computation of [`androscalpel_serializer::Serializable::size`]
/// for a specific field `f` accessible using `field_ref`.
fn get_implem_size_for_field(f: &Field, field_ref: TokenStream) -> TokenStream {
let params = ParamsField::parse(&f.attrs);
let prefix_stream = if let Some(PrefixParamsField(ref stream)) = params.prefix {
quote_spanned! { f.span() =>
#stream.iter().collect::<Vec<_>>().len()
}
} else {
quote_spanned! { f.span() => 0 }
};
let suffix_stream = if let Some(SuffixParamsField(ref stream)) = params.suffix {
quote_spanned! { f.span() =>
#stream.iter().collect::<Vec<_>>().len()
}
} else {
quote_spanned! { f.span() => 0 }
};
let main_stream = match (&f.ty, params) {
(
_,
ParamsField {
until: Some(UntilParams(d, u, until)),
..
},
) => quote_spanned! { f.span() =>
androscalpel_serializer::SerializableUntil::<#d, #u>::size(&#field_ref, #until)
},
(Type::Array(_), ParamsField { until: None, .. }) => quote_spanned! { f.span() =>
#field_ref.iter().map(androscalpel_serializer::Serializable::size).sum::<usize>()
},
(_, ParamsField { until: None, .. }) => quote_spanned! { f.span() =>
androscalpel_serializer::Serializable::size(&#field_ref)
},
};
quote_spanned! { f.span() => #prefix_stream + #main_stream + #suffix_stream }
}
/// Return the implementation of the [`androscalpel_serializer::Serializable::size`].
fn get_implem_size(data: &Data, params: &ParamsStruct) -> TokenStream {
match *data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
get_implem_size_for_field(f, quote! { self.#name })
});
quote! {
0 #(+ #recurse)*
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().enumerate().map(|(i, f)| {
let index = Index::from(i);
get_implem_size_for_field(f, quote! { self.#index })
});
quote! {
0 #(+ #recurse)*
}
}
Fields::Unit => quote!(0),
},
Data::Enum(ref data) => {
let PrefixTypeParams(prefix_ty) = params.prefix_type.as_ref().expect(
"Cannot derive Serializable for an enum without the #[prefix_type(T)] attribute",
);
let recurse = data.variants.iter().map(|v| {
let ident = &v.ident;
let params = ParamsVariant::parse(&v.attrs);
// let prefix = params.prefix.expect(
// "Cannot derive Serializable for variant without the #[prefix(val)] attribute",
// );
// let PrefixParamsVariant(val) = prefix;
let prefix_quote = match params {
ParamsVariant {prefix: Some(PrefixParamsVariant(val)), default_variant: None } => quote_spanned! { v.span() => <#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) },
ParamsVariant {prefix: None, default_variant: Some(()) } => quote! { 0 }, // The prefix is in the first field
ParamsVariant {prefix: None, default_variant: None } => panic!("Cannot derive Serializable for variant without the #[prefix(val)] or #[default_variant] attribute"),
ParamsVariant {prefix: Some(_), default_variant: Some(()) } => panic! ("A variant cannot be the default one and specify a prefix value"),
};
let match_ = get_enum_match(v);
let body = match v.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
get_implem_size_for_field(f, quote! { *#name })
});
quote_spanned! { v.span() =>
//<#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) #(+#recurse )*
#prefix_quote #(+#recurse )*
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().enumerate().map(|(i, f)| {
let ident = format_ident!("field{}", i);
get_implem_size_for_field(f, quote! { *#ident })
});
quote_spanned! { v.span() =>
//<#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) #(+#recurse )*
#prefix_quote #(+#recurse )*
}
}
//Fields::Unit => quote! { <#prefix_ty as androscalpel_serializer::Serializable>::size(&#val) },
Fields::Unit => quote! { #prefix_quote },
};
quote_spanned! { v.span() =>
Self::#ident #match_ => { #body },
}
});
quote! { match self {
#(#recurse)*
}}
}
Data::Union(_) => unimplemented!(),
}
}
/// Return the implementation of the computation of [`androscalpel_serializer::Serializable::serialize`]
/// for a specific field `f` accessible using `field_ref`.
fn get_implem_serialize_for_field(f: &Field, field_ref: TokenStream) -> TokenStream {
let params = ParamsField::parse(&f.attrs);
// TODO: Improve error handling
let prefix_stream = if let Some(PrefixParamsField(ref stream)) = params.prefix {
quote_spanned! { f.span() =>
for byte in #stream {
<u8 as androscalpel_serializer::Serializable>::serialize(&byte, output)?;
}
}
} else {
quote_spanned! { f.span() => }
};
let suffix_stream = if let Some(SuffixParamsField(ref stream)) = params.suffix {
quote_spanned! { f.span() =>
for byte in #stream {
<u8 as androscalpel_serializer::Serializable>::serialize(&byte, output)?;
}
}
} else {
quote_spanned! { f.span() => }
};
let main_stream = match (&f.ty, params) {
(
_,
ParamsField {
until: Some(UntilParams(d, u, until)),
..
},
) => quote_spanned! { f.span() =>
androscalpel_serializer::SerializableUntil::<#d, #u>::serialize(&#field_ref, output, #until)?;
},
(Type::Array(_), ParamsField { until: None, .. }) => quote_spanned! { f.span() =>
for x in #field_ref {
androscalpel_serializer::Serializable::serialize(&x, output)?;
}
},
(_, ParamsField { until: None, .. }) => quote_spanned! { f.span() =>
androscalpel_serializer::Serializable::serialize(&#field_ref, output)?;
},
};
quote_spanned! { f.span() =>
#prefix_stream
#main_stream
#suffix_stream
}
}
/// Return the implementation of the [`androscalpel_serializer::Serializable::serialize`].
fn get_implem_serialize(data: &Data, params: &ParamsStruct) -> TokenStream {
match *data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
get_implem_serialize_for_field(f, quote! { self.#name })
});
quote! {
#(#recurse)*
Ok(())
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().enumerate().map(|(i, f)| {
let index = Index::from(i);
get_implem_serialize_for_field(f, quote! { self.#index })
});
quote! {
#(#recurse)*
Ok(())
}
}
Fields::Unit => quote!(0),
},
Data::Enum(ref data) => {
let PrefixTypeParams(prefix_ty) = params.prefix_type.as_ref().expect(
"Cannot derive Serializable for an enum without the #[prefix_type(T)] attribute",
);
let recurse = data.variants.iter().map(|v| {
let ident = &v.ident;
let params = ParamsVariant::parse(&v.attrs);
//let prefix = params.prefix.expect(
// "Cannot derive Serializable for variant without the #[prefix(val)] attribute",
//);
//let PrefixParamsVariant(val) = prefix;
let prefix_quote = match params {
ParamsVariant {prefix: Some(PrefixParamsVariant(val)), default_variant: None } => quote_spanned! { v.span() => <#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?; },
ParamsVariant {prefix: None, default_variant: Some(()) } => quote! {},
ParamsVariant {prefix: None, default_variant: None } => panic!("Cannot derive Serializable for variant without the #[prefix(val)] or #[default_variant] attribute"),
ParamsVariant {prefix: Some(_), default_variant: Some(()) } => panic! ("A variant cannot be the default one and specify a prefix value"),
};
let match_ = get_enum_match(v);
let body = match v.fields {
Fields::Named(ref fields) => {
if params.default_variant.is_some() && fields
.named
.first()
.unwrap()
.ident
.as_ref()
.expect(
"Default variant must have a least one field for the prefix"
) != "prefix" {
panic!(
"The first field of a named field variant must be named `prefix` and of the type of the prefix of the enum"
);
}
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
get_implem_serialize_for_field(f, quote! { *#name })
});
quote_spanned! { v.span() =>
//<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
#prefix_quote
#(#recurse)*
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields.unnamed.iter().enumerate().map(|(i, f)| {
let ident = format_ident!("field{}", i);
get_implem_serialize_for_field(f, quote! { *#ident })
});
quote_spanned! { v.span() =>
//<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
#prefix_quote
#(#recurse)*
}
}
Fields::Unit => quote! {
//<#prefix_ty as androscalpel_serializer::Serializable>::serialize(&#val, output)?;
#prefix_quote
},
};
quote_spanned! { v.span() =>
Self::#ident #match_ => { #body },
}
});
quote! {
match self {
#(#recurse)*
}
Ok(())
}
}
Data::Union(_) => unimplemented!(),
}
}
/// Return the implementation of the computation of [`androscalpel_serializer::Serializable::deserialize`]
/// for a specific field `f` accessible using `field_ref`.
fn get_implem_deserialize_for_field(f: &Field, field_ref: TokenStream) -> TokenStream {
let params = ParamsField::parse(&f.attrs);
let ty = &f.ty;
// TODO: Improve error handling
let prefix_stream = if let Some(PrefixParamsField(ref stream)) = params.prefix {
quote_spanned! { f.span() =>
for byte in #stream {
if <u8 as androscalpel_serializer::Serializable>::deserialize(input)? != byte {
return Err(androscalpel_serializer::Error::DeserializationError(
"Prefix do not match #stream".into()
));
}
}
}
} else {
quote_spanned! { f.span() => }
};
let suffix_stream = if let Some(SuffixParamsField(ref stream)) = params.suffix {
quote_spanned! { f.span() =>
for byte in #stream {
if <u8 as androscalpel_serializer::Serializable>::deserialize(input)? != byte {
return Err(androscalpel_serializer::Error::DeserializationError(
"Suffix do not match #stream".into()
));
}
}
}
} else {
quote_spanned! { f.span() => }
};
match (ty, params) {
(
_,
ParamsField {
until: Some(UntilParams(d, u, until)),
..
},
) => quote_spanned! { f.span() =>
#field_ref {
#prefix_stream
let val = <#ty as androscalpel_serializer::SerializableUntil::<#d, #u>>::deserialize(input, #until)?;
#suffix_stream
val
},
},
(Type::Array(arr), ParamsField { until: None, .. }) => {
let len = &arr.len;
let arr_ty = &arr.elem;
quote_spanned! { f.span() =>
#field_ref {
#prefix_stream
let mut vec_ = vec![];
for _ in 0..(#len) {
vec_.push(<#arr_ty as androscalpel_serializer::Serializable>::deserialize(input)?);
}
#suffix_stream
vec_.try_into().unwrap()
},
}
}
(_, ParamsField { until: None, .. }) => quote_spanned! { f.span() =>
#field_ref {
#prefix_stream
let val = <#ty as androscalpel_serializer::Serializable>::deserialize(input)?;
#suffix_stream
val
},
},
}
}
/// Return the implementation of the [`androscalpel_serializer::Serializable::deserialize`].
fn get_implem_deserialize(data: &Data, params: &ParamsStruct) -> TokenStream {
match *data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
get_implem_deserialize_for_field(f, quote! { #name: })
});
quote! {
Ok(
Self {
#(#recurse)*
}
)
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields
.unnamed
.iter()
.map(|f| get_implem_deserialize_for_field(f, quote! {}));
quote! {
Ok(Self(#(#recurse)*))
}
}
Fields::Unit => quote!(0),
},
Data::Enum(ref data) => {
let PrefixTypeParams(prefix_ty) = params.prefix_type.as_ref().expect(
"Cannot derive Serializable for an enum without the #[prefix_type(T)] attribute",
);
let recurse = data.variants.iter().map(|v| {
let v_ident = &v.ident;
let v_params = ParamsVariant::parse(&v.attrs);
// Serialization of default value at the end
if v_params.default_variant.is_some() {
return quote! {};
}
let PrefixParamsVariant(val) = v_params.prefix.expect(
"Cannot derive Serializable for variant without the #[prefix(val)] attribute",
);
match v.fields {
Fields::Named(ref fields) => {
let recurse = fields.named.iter().map(|f| {
let name = &f.ident;
get_implem_deserialize_for_field(f, quote! { #name: })
});
quote_spanned! { v.span() =>
if #val == prefix {
return Ok(Self::#v_ident {#(#recurse)*});
}
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields
.unnamed
.iter()
.map(|f| get_implem_deserialize_for_field(f, quote! {}));
quote_spanned! { v.span() =>
if #val == prefix {
return Ok(Self::#v_ident (#(#recurse)*));
}
}
}
Fields::Unit => quote_spanned! { v.span() =>
if #val == prefix {
return Ok(Self::#v_ident);
}
},
}
});
let mut default_variant = None;
for v in &data.variants {
let v_params = ParamsVariant::parse(&v.attrs);
if v_params.default_variant.is_some() && v_params.prefix.is_some() {
panic!("A variant cannot be both the default variant and check a prefix value");
}
if v_params.default_variant.is_some() && default_variant.is_some() {
panic!("An enum can only have one variant marked as `default_variant`");
}
if v_params.default_variant.is_some() {
default_variant = Some(v);
}
}
let default_quote = match default_variant {
None => quote! {
Err(androscalpel_serializer::Error::SerializationError(format!(
"Found prefix {:?} that did not match any variant.", prefix
)))
},
Some(v) => {
let v_ident = &v.ident;
match v.fields {
Fields::Named(ref fields) => {
// Skip 1 because the first field is the prefix
// TODO: check first field name is `prefix`?
let recurse = fields.named.iter().skip(1).map(|f| {
let name = &f.ident;
get_implem_deserialize_for_field(f, quote! { #name: })
});
quote_spanned! { v.span() =>
return Ok(Self::#v_ident {prefix, #(#recurse)*});
}
}
Fields::Unnamed(ref fields) => {
let recurse = fields
.unnamed
.iter()
.skip(1)
.map(|f| get_implem_deserialize_for_field(f, quote! {}));
quote_spanned! { v.span() =>
return Ok(Self::#v_ident (prefix, #(#recurse)*));
}
}
Fields::Unit => quote_spanned! { v.span() =>
return Ok(Self::#v_ident);
},
}
}
};
quote! {
let prefix = <#prefix_ty as androscalpel_serializer::Serializable>::deserialize(input)?;
#(#recurse)*
//Err(androscalpel_serializer::Error::SerializationError(format!(
// "Found prefix {:?} that did not match any variant.", prefix
//)))
#default_quote
}
}
Data::Union(_) => unimplemented!(),
}
}