codama_attributes/codama_directives/
size_prefix_directive.rs

1use crate::{utils::FromMeta, Attribute, CodamaAttribute, CodamaDirective};
2use codama_errors::CodamaError;
3use codama_nodes::{NestedTypeNode, NumberTypeNode, TypeNode};
4use codama_syn_helpers::{extensions::*, Meta};
5
6#[derive(Debug, PartialEq)]
7pub struct SizePrefixDirective {
8    pub prefix: NestedTypeNode<NumberTypeNode>,
9}
10
11impl SizePrefixDirective {
12    pub fn parse(meta: &Meta) -> syn::Result<Self> {
13        let pv = meta.assert_directive("size_prefix")?.as_path_value()?;
14        let node = TypeNode::from_meta(&pv.value)?;
15        let prefix = match NestedTypeNode::<NumberTypeNode>::try_from(node) {
16            Ok(node) => node,
17            Err(_) => return Err(pv.value.error("prefix must be a NumberTypeNode")),
18        };
19        Ok(Self { prefix })
20    }
21}
22
23impl<'a> TryFrom<&'a CodamaAttribute<'a>> for &'a SizePrefixDirective {
24    type Error = CodamaError;
25
26    fn try_from(attribute: &'a CodamaAttribute) -> Result<Self, Self::Error> {
27        match attribute.directive {
28            CodamaDirective::SizePrefix(ref a) => Ok(a),
29            _ => Err(CodamaError::InvalidCodamaDirective {
30                expected: "size_prefix".to_string(),
31                actual: attribute.directive.name().to_string(),
32            }),
33        }
34    }
35}
36
37impl<'a> TryFrom<&'a Attribute<'a>> for &'a SizePrefixDirective {
38    type Error = CodamaError;
39
40    fn try_from(attribute: &'a Attribute) -> Result<Self, Self::Error> {
41        <&CodamaAttribute>::try_from(attribute)?.try_into()
42    }
43}
44
45#[cfg(test)]
46mod tests {
47    use super::*;
48    use codama_nodes::NumberFormat::U32;
49
50    #[test]
51    fn ok() {
52        let meta: Meta = syn::parse_quote! { size_prefix = number(u32) };
53        let directive = SizePrefixDirective::parse(&meta).unwrap();
54        assert_eq!(
55            directive,
56            SizePrefixDirective {
57                prefix: NumberTypeNode::le(U32).into(),
58            }
59        );
60    }
61}
codama_attributes/codama_directives/size_prefix_directive.rs

codama_attributes/codama_directives/
size_prefix_directive.rs
