borsh_derive/internals/attributes/
parsing.rs

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1use std::{collections::BTreeMap, iter::FromIterator};
2
3use syn::{
4    meta::ParseNestedMeta, punctuated::Punctuated, token::Paren, Attribute, Expr, Lit, LitStr,
5    Token,
6};
7
8use super::Symbol;
9
10fn get_lit_str2(
11    attr_name: Symbol,
12    meta_item_name: Symbol,
13    meta: &ParseNestedMeta,
14) -> syn::Result<LitStr> {
15    let expr: Expr = meta.value()?.parse()?;
16    let mut value = &expr;
17    while let Expr::Group(e) = value {
18        value = &e.expr;
19    }
20    if let Expr::Lit(syn::ExprLit {
21        lit: Lit::Str(lit), ..
22    }) = value
23    {
24        Ok(lit.clone())
25    } else {
26        Err(syn::Error::new_spanned(
27            expr,
28            format!(
29                "expected borsh {} attribute to be a string: `{} = \"...\"`",
30                attr_name.0, meta_item_name.0
31            ),
32        ))
33    }
34}
35
36pub(super) fn parse_lit_into<T: syn::parse::Parse>(
37    attr_name: Symbol,
38    meta_item_name: Symbol,
39    meta: &ParseNestedMeta,
40) -> syn::Result<T> {
41    let string = get_lit_str2(attr_name, meta_item_name, meta)?;
42
43    match string.parse() {
44        Ok(expr) => Ok(expr),
45        Err(err) => Err(syn::Error::new_spanned(string, err)),
46    }
47}
48
49pub(super) fn parse_lit_into_vec<T: syn::parse::Parse>(
50    attr_name: Symbol,
51    meta_item_name: Symbol,
52    meta: &ParseNestedMeta,
53) -> syn::Result<Vec<T>> {
54    let string = get_lit_str2(attr_name, meta_item_name, meta)?;
55
56    match string.parse_with(Punctuated::<T, Token![,]>::parse_terminated) {
57        Ok(elements) => Ok(Vec::from_iter(elements)),
58        Err(err) => Err(syn::Error::new_spanned(string, err)),
59    }
60}
61
62fn get_nested_meta_logic<T, F>(
63    attr_name: Symbol,
64    meta: ParseNestedMeta,
65    map: &BTreeMap<Symbol, F>,
66    result: &mut BTreeMap<Symbol, T>,
67) -> syn::Result<()>
68where
69    F: Fn(Symbol, Symbol, &ParseNestedMeta) -> syn::Result<T>,
70{
71    let mut match_ = false;
72    for (symbol_key, func) in map.iter() {
73        if meta.path == *symbol_key {
74            let v = func(attr_name, *symbol_key, &meta)?;
75            result.insert(*symbol_key, v);
76            match_ = true;
77        }
78    }
79    if !match_ {
80        let keys_strs = map.keys().map(|symbol| symbol.1).collect::<Vec<_>>();
81        let keys_strs = keys_strs.join(", ");
82        return Err(meta.error(format_args!(
83            "malformed {0} attribute, expected `{0}({1})`",
84            attr_name.0, keys_strs
85        )));
86    }
87    Ok(())
88}
89
90pub(super) fn meta_get_by_symbol_keys<T, F>(
91    attr_name: Symbol,
92    meta: &ParseNestedMeta,
93    map: &BTreeMap<Symbol, F>,
94) -> syn::Result<BTreeMap<Symbol, T>>
95where
96    F: Fn(Symbol, Symbol, &ParseNestedMeta) -> syn::Result<T>,
97{
98    let mut result = BTreeMap::new();
99
100    let lookahead = meta.input.lookahead1();
101    if lookahead.peek(Paren) {
102        meta.parse_nested_meta(|meta| get_nested_meta_logic(attr_name, meta, map, &mut result))?;
103    } else {
104        return Err(lookahead.error());
105    }
106
107    Ok(result)
108}
109
110pub(super) fn attr_get_by_symbol_keys<T, F>(
111    attr_name: Symbol,
112    attr: &Attribute,
113    map: &BTreeMap<Symbol, F>,
114) -> syn::Result<BTreeMap<Symbol, T>>
115where
116    F: Fn(Symbol, Symbol, &ParseNestedMeta) -> syn::Result<T>,
117{
118    let mut result = BTreeMap::new();
119
120    attr.parse_nested_meta(|meta| get_nested_meta_logic(attr_name, meta, map, &mut result))?;
121
122    Ok(result)
123}
borsh_derive/internals/attributes/parsing.rs

borsh_derive/internals/attributes/
parsing.rs
