vendor/darling_core/src/codegen/error.rs

   1 use proc_macro2::TokenStream;
   2 use quote::{TokenStreamExt, ToTokens};
   3
   4 /// Declares the local variable into which errors will be accumulated.
   5 #[derive(Default)]
   6 pub struct ErrorDeclaration {
   7     __hidden: (),
   8 }
   9
  10 impl ToTokens for ErrorDeclaration {
  11     fn to_tokens(&self, tokens: &mut TokenStream) {
  12         tokens.append_all(quote! {
  13             let mut __errors = ::darling::export::Vec::new();
  14         })
  15     }
  16 }
  17
  18 /// Returns early if attribute or body parsing has caused any errors.
  19 #[derive(Default)]
  20 pub struct ErrorCheck<'a> {
  21     location: Option<&'a str>,
  22     __hidden: (),
  23 }
  24
  25 impl<'a> ErrorCheck<'a> {
  26     pub fn with_location(location: &'a str) -> Self {
  27         ErrorCheck {
  28             location: Some(location),
  29             __hidden: (),
  30         }
  31     }
  32 }
  33
  34 impl<'a> ToTokens for ErrorCheck<'a> {
  35     fn to_tokens(&self, tokens: &mut TokenStream) {
  36         let at_call = if let Some(ref s) = self.location {
  37             quote!(.at(#s))
  38         } else {
  39             quote!()
  40         };
  41
  42         tokens.append_all(quote! {
  43             if !__errors.is_empty() {
  44                 return ::darling::export::Err(::darling::Error::multiple(__errors) #at_call);
  45             }
  46         })
  47     }
  48 }