1use proc_macro2::TokenStream;
2use quote::ToTokens;
3
4use crate::ast::Data;
5use crate::codegen::FromMetaImpl;
6use crate::error::Accumulator;
7use crate::options::{Core, ParseAttribute, ParseData};
8use crate::{Error, Result};
9
10pub struct FromMetaOptions {
11 base: Core,
12}
13
14impl FromMetaOptions {
15 pub fn new(di: &syn::DeriveInput) -> Result<Self> {
16 (FromMetaOptions {
17 base: Core::start(di)?,
18 })
19 .parse_attributes(&di.attrs)?
20 .parse_body(&di.data)
21 }
22}
23
24impl ParseAttribute for FromMetaOptions {
25 fn parse_nested(&mut self, mi: &syn::Meta) -> Result<()> {
26 self.base.parse_nested(mi)
27 }
28}
29
30impl ParseData for FromMetaOptions {
31 fn parse_variant(&mut self, variant: &syn::Variant) -> Result<()> {
32 self.base.parse_variant(variant)
33 }
34
35 fn parse_field(&mut self, field: &syn::Field) -> Result<()> {
36 self.base.parse_field(field)
37 }
38
39 fn validate_body(&self, errors: &mut Accumulator) {
40 self.base.validate_body(errors);
41
42 if let Data::Enum(ref data) = self.base.data {
43 // Adds errors for duplicate `#[darling(word)]` annotations across all variants.
44 let word_variants: Vec<_> = data
45 .iter()
46 .filter_map(|variant| variant.word.as_ref())
47 .collect();
48 if word_variants.len() > 1 {
49 for word in word_variants {
50 errors.push(
51 Error::custom("`#[darling(word)]` can only be applied to one variant")
52 .with_span(&word.span()),
53 );
54 }
55 }
56 }
57 }
58}
59
60impl<'a> From<&'a FromMetaOptions> for FromMetaImpl<'a> {
61 fn from(v: &'a FromMetaOptions) -> Self {
62 FromMetaImpl {
63 base: (&v.base).into(),
64 }
65 }
66}
67
68impl ToTokens for FromMetaOptions {
69 fn to_tokens(&self, tokens: &mut TokenStream) {
70 FromMetaImpl::from(self).to_tokens(tokens)
71 }
72}
73