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#[cfg(feature = "legacy")]
use macro_compose::{Collector, Lint};
#[cfg(feature = "legacy")]
use quote::ToTokens;
use std::convert::TryFrom;
#[cfg(feature = "legacy")]
use syn::Lit;
use syn::{parse_quote, Error, GenericArgument, Path, PathArguments};
#[derive(Clone, Copy, Debug)]
/// the type of a field
pub struct Type {
/// the actual type
pub ty: Types,
/// whether or not the value for the type is optional
pub optional: bool,
}
#[cfg(feature = "legacy")]
impl<'a> Lint<Option<&'a Lit>> for Type {
fn lint(&self, input: &Option<&'a Lit>, c: &mut Collector) {
let ty = match self.ty {
Types::Any => "anything",
Types::Flag => "nothing",
Types::Str => "string",
Types::ByteStr => "byte string",
Types::Byte => "byte",
Types::Char => "char",
Types::I32 => "i32",
Types::F32 => "f32",
Types::Bool => "bool",
Types::Idents => "idents",
};
match (input, self.ty) {
(Some(_), Types::Any)
| (None, Types::Flag)
| (Some(Lit::Str(_)), Types::Str)
| (Some(Lit::ByteStr(_)), Types::ByteStr)
| (Some(Lit::Byte(_)), Types::Byte)
| (Some(Lit::Char(_)), Types::Char)
| (Some(Lit::Int(_)), Types::I32)
| (Some(Lit::Float(_)), Types::F32)
| (Some(Lit::Bool(_)), Types::Bool) => {}
(None, _) if self.optional => {}
(Some(lit), _) => c.error(Error::new_spanned(
input,
format!("expected {}, got {}", ty, lit.to_token_stream()),
)),
(None, _) => c.error(Error::new_spanned(
input,
format!("expected {}, got nothing", ty,),
)),
}
}
}
#[derive(Clone, Copy, Debug)]
/// all the types a field can contain
pub enum Types {
/// can contain any literal
Any,
/// doesn't have a value eg `#[my_input(enabled)]`
Flag,
/// for string
Str,
/// for bytestring
ByteStr,
/// for u8
Byte,
/// for char
Char,
/// for i32
I32,
/// for f32
F32,
/// for bool
Bool,
/// for idents
Idents,
}
impl TryFrom<&syn::Type> for Type {
type Error = Error;
fn try_from(ty: &syn::Type) -> Result<Self, Self::Error> {
let byte_vec_path: Path = parse_quote!(Vec<u8>);
let ident_vec_path: Path = parse_quote!(Vec<Ident>);
let error = || Err(Error::new_spanned(&ty, "unexpected type"));
match ty {
syn::Type::Path(p) => {
if p.path.is_ident("String") {
Ok(Type {
ty: Types::Str,
optional: false,
})
} else if p.path == byte_vec_path {
Ok(Type {
ty: Types::ByteStr,
optional: false,
})
} else if p.path == ident_vec_path {
Ok(Type {
ty: Types::Idents,
optional: false,
})
} else if p.path.is_ident("u8") {
Ok(Type {
ty: Types::Byte,
optional: false,
})
} else if p.path.is_ident("char") {
Ok(Type {
ty: Types::Char,
optional: false,
})
} else if p.path.is_ident("i32") {
Ok(Type {
ty: Types::I32,
optional: false,
})
} else if p.path.is_ident("f32") {
Ok(Type {
ty: Types::F32,
optional: false,
})
} else if p.path.is_ident("bool") {
Ok(Type {
ty: Types::Bool,
optional: false,
})
} else {
if p.path.segments.len() == 1 {
let segment = p.path.segments.first().unwrap();
if segment.ident == "Option" {
if let PathArguments::AngleBracketed(args) = &segment.arguments {
if let Some(GenericArgument::Type(ty)) = args.args.first() {
return Type::try_from(ty).and_then(|ty| {
if ty.optional {
error()
} else {
Ok(Type {
ty: ty.ty,
optional: true,
})
}
});
}
}
}
}
error()
}
}
syn::Type::Tuple(t) if t.elems.is_empty() => Ok(Type {
ty: Types::Flag,
optional: false,
}),
_ => error(),
}
}
}