anchor_syn/parser/
error.rs

1use {
2    crate::{Error, ErrorArgs, ErrorCode},
3    syn::{
4        parse::{Parse, Result as ParseResult},
5        Expr,
6    },
7};
8
9// Removes any internal #[msg] attributes, as they are inert.
10pub fn parse(error_enum: &mut syn::ItemEnum, args: Option<ErrorArgs>) -> Error {
11    let ident = error_enum.ident.clone();
12    let mut last_discriminant = 0;
13    let codes: Vec<ErrorCode> = error_enum
14        .variants
15        .iter_mut()
16        .map(|variant: &mut syn::Variant| {
17            let msg = parse_error_attribute(variant);
18            let ident = variant.ident.clone();
19            let id = match &variant.discriminant {
20                None => last_discriminant,
21                Some((_, disc)) => match disc {
22                    syn::Expr::Lit(expr_lit) => match &expr_lit.lit {
23                        syn::Lit::Int(int) => {
24                            int.base10_parse::<u32>().expect("Must be a base 10 number")
25                        }
26                        _ => panic!("Invalid error discriminant"),
27                    },
28                    _ => panic!("Invalid error discriminant"),
29                },
30            };
31            last_discriminant = id + 1;
32
33            // Remove any non-doc attributes on the error variant.
34            variant
35                .attrs
36                .retain(|attr| attr.path.segments[0].ident == "doc");
37
38            ErrorCode { id, ident, msg }
39        })
40        .collect();
41    Error {
42        name: error_enum.ident.to_string(),
43        raw_enum: error_enum.clone(),
44        ident,
45        codes,
46        args,
47    }
48}
49
50fn parse_error_attribute(variant: &syn::Variant) -> Option<String> {
51    let attrs = variant
52        .attrs
53        .iter()
54        .filter(|attr| attr.path.segments[0].ident != "doc")
55        .collect::<Vec<_>>();
56    match attrs.len() {
57        0 => None,
58        1 => {
59            let attr = &attrs[0];
60            let attr_str = attr.path.segments[0].ident.to_string();
61            assert!(&attr_str == "msg", "Use msg to specify error strings");
62
63            let mut tts = attr.tokens.clone().into_iter();
64            let g_stream = match tts.next().expect("Must have a token group") {
65                proc_macro2::TokenTree::Group(g) => g.stream(),
66                _ => panic!("Invalid syntax"),
67            };
68
69            let msg = match g_stream.into_iter().next() {
70                None => panic!("Must specify a message string"),
71                Some(msg) => msg.to_string().replace('\"', ""),
72            };
73
74            Some(msg)
75        }
76        _ => {
77            panic!("Too many attributes found. Use `msg` to specify error strings");
78        }
79    }
80}
81
82pub struct ErrorInput {
83    pub error_code: Expr,
84}
85
86impl Parse for ErrorInput {
87    fn parse(stream: syn::parse::ParseStream) -> ParseResult<Self> {
88        let error_code = stream.call(Expr::parse)?;
89        Ok(Self { error_code })
90    }
91}
anchor_syn/parser/error.rs

anchor_syn/parser/
error.rs
