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use proc_macro2::TokenStream;
use quote::ToTokens;
use crate::ast::Data;
use crate::codegen::FromMetaImpl;
use crate::error::Accumulator;
use crate::options::{Core, ParseAttribute, ParseData};
use crate::{Error, Result};
pub struct FromMetaOptions {
base: Core,
}
impl FromMetaOptions {
pub fn new(di: &syn::DeriveInput) -> Result<Self> {
(FromMetaOptions {
base: Core::start(di)?,
})
.parse_attributes(&di.attrs)?
.parse_body(&di.data)
}
}
impl ParseAttribute for FromMetaOptions {
fn parse_nested(&mut self, mi: &syn::Meta) -> Result<()> {
self.base.parse_nested(mi)
}
}
impl ParseData for FromMetaOptions {
fn parse_variant(&mut self, variant: &syn::Variant) -> Result<()> {
self.base.parse_variant(variant)
}
fn parse_field(&mut self, field: &syn::Field) -> Result<()> {
self.base.parse_field(field)
}
fn validate_body(&self, errors: &mut Accumulator) {
self.base.validate_body(errors);
if let Data::Enum(ref data) = self.base.data {
// Adds errors for duplicate `#[darling(word)]` annotations across all variants.
let word_variants: Vec<_> = data
.iter()
.filter_map(|variant| variant.word.as_ref())
.collect();
if word_variants.len() > 1 {
for word in word_variants {
errors.push(
Error::custom("`#[darling(word)]` can only be applied to one variant")
.with_span(&word.span()),
);
}
}
}
}
}
impl<'a> From<&'a FromMetaOptions> for FromMetaImpl<'a> {
fn from(v: &'a FromMetaOptions) -> Self {
FromMetaImpl {
base: (&v.base).into(),
}
}
}
impl ToTokens for FromMetaOptions {
fn to_tokens(&self, tokens: &mut TokenStream) {
FromMetaImpl::from(self).to_tokens(tokens)
}
}