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use std::borrow::Cow;
use crate::{
attributes::{self, get_pyo3_options, is_attribute_ident, take_attributes, NameAttribute},
deprecations::Deprecations,
};
use proc_macro2::{Ident, TokenStream};
use quote::quote;
use syn::{
ext::IdentExt,
parse::{Parse, ParseStream},
spanned::Spanned,
Result,
};
pub struct ConstSpec {
pub rust_ident: syn::Ident,
pub attributes: ConstAttributes,
}
impl ConstSpec {
pub fn python_name(&self) -> Cow<Ident> {
if let Some(name) = &self.attributes.name {
Cow::Borrowed(&name.0)
} else {
Cow::Owned(self.rust_ident.unraw())
}
}
pub fn null_terminated_python_name(&self) -> TokenStream {
let name = format!("{}\0", self.python_name());
quote!({#name})
}
}
pub struct ConstAttributes {
pub is_class_attr: bool,
pub name: Option<NameAttribute>,
pub deprecations: Deprecations,
}
pub enum PyO3ConstAttribute {
Name(NameAttribute),
}
impl Parse for PyO3ConstAttribute {
fn parse(input: ParseStream) -> Result<Self> {
let lookahead = input.lookahead1();
if lookahead.peek(attributes::kw::name) {
input.parse().map(PyO3ConstAttribute::Name)
} else {
Err(lookahead.error())
}
}
}
impl ConstAttributes {
pub fn from_attrs(attrs: &mut Vec<syn::Attribute>) -> syn::Result<Self> {
let mut attributes = ConstAttributes {
is_class_attr: false,
name: None,
deprecations: Deprecations::new(),
};
take_attributes(attrs, |attr| {
if is_attribute_ident(attr, "classattr") {
ensure_spanned!(
attr.tokens.is_empty(),
attr.span() => "`#[classattr]` does not take any arguments"
);
attributes.is_class_attr = true;
Ok(true)
} else if let Some(pyo3_attributes) = get_pyo3_options(attr)? {
for pyo3_attr in pyo3_attributes {
match pyo3_attr {
PyO3ConstAttribute::Name(name) => attributes.set_name(name)?,
}
}
Ok(true)
} else {
Ok(false)
}
})?;
Ok(attributes)
}
fn set_name(&mut self, name: NameAttribute) -> Result<()> {
ensure_spanned!(
self.name.is_none(),
name.0.span() => "`name` may only be specified once"
);
self.name = Some(name);
Ok(())
}
}
