anchor_syn/parser/
error.rs

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

anchor_syn/parser/
error.rs
