Source code
Revision control
Copy as Markdown
Other Tools
use crate::ARBITRARY_ATTRIBUTE_NAME;
use syn::{
parse::Error, punctuated::Punctuated, DeriveInput, Expr, ExprLit, Lit, Meta, MetaNameValue,
Token, TypeParam,
};
pub struct ContainerAttributes {
/// Specify type bounds to be applied to the derived `Arbitrary` implementation instead of the
/// default inferred bounds.
///
/// ```ignore
/// #[arbitrary(bound = "T: Default, U: Debug")]
/// ```
///
/// Multiple attributes will be combined as long as they don't conflict, e.g.
///
/// ```ignore
/// #[arbitrary(bound = "T: Default")]
/// #[arbitrary(bound = "U: Default")]
/// ```
pub bounds: Option<Vec<Punctuated<TypeParam, Token![,]>>>,
}
impl ContainerAttributes {
pub fn from_derive_input(derive_input: &DeriveInput) -> Result<Self, Error> {
let mut bounds = None;
for attr in &derive_input.attrs {
if !attr.path().is_ident(ARBITRARY_ATTRIBUTE_NAME) {
continue;
}
let meta_list = match attr.meta {
Meta::List(ref l) => l,
_ => {
return Err(Error::new_spanned(
attr,
format!(
"invalid `{}` attribute. expected list",
ARBITRARY_ATTRIBUTE_NAME
),
))
}
};
for nested_meta in
meta_list.parse_args_with(Punctuated::<Meta, Token![,]>::parse_terminated)?
{
match nested_meta {
Meta::NameValue(MetaNameValue {
path,
value:
Expr::Lit(ExprLit {
lit: Lit::Str(bound_str_lit),
..
}),
..
}) if path.is_ident("bound") => {
bounds
.get_or_insert_with(Vec::new)
.push(bound_str_lit.parse_with(Punctuated::parse_terminated)?);
}
_ => {
return Err(Error::new_spanned(
attr,
format!(
"invalid `{}` attribute. expected `bound = \"..\"`",
ARBITRARY_ATTRIBUTE_NAME,
),
))
}
}
}
}
Ok(Self { bounds })
}
}