diff options
Diffstat (limited to 'third_party/rust/serde_with_macros/src/utils.rs')
-rw-r--r-- | third_party/rust/serde_with_macros/src/utils.rs | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/third_party/rust/serde_with_macros/src/utils.rs b/third_party/rust/serde_with_macros/src/utils.rs new file mode 100644 index 0000000000..068cbce6ed --- /dev/null +++ b/third_party/rust/serde_with_macros/src/utils.rs @@ -0,0 +1,77 @@ +use core::iter::Iterator; +use darling::FromDeriveInput; +use proc_macro::TokenStream; +use proc_macro2::TokenStream as TokenStream2; +use quote::ToTokens; +use syn::{parse_quote, Error, Generics, Path, TypeGenerics}; + +/// Merge multiple [`syn::Error`] into one. +pub(crate) trait IteratorExt { + fn collect_error(self) -> Result<(), Error> + where + Self: Iterator<Item = Result<(), Error>> + Sized, + { + let accu = Ok(()); + self.fold(accu, |accu, error| match (accu, error) { + (Ok(()), error) => error, + (accu, Ok(())) => accu, + (Err(mut err), Err(error)) => { + err.combine(error); + Err(err) + } + }) + } +} +impl<I> IteratorExt for I where I: Iterator<Item = Result<(), Error>> + Sized {} + +/// Attributes usable for derive macros +#[derive(FromDeriveInput)] +#[darling(attributes(serde_with))] +pub(crate) struct DeriveOptions { + /// Path to the crate + #[darling(rename = "crate", default)] + pub(crate) alt_crate_path: Option<Path>, +} + +impl DeriveOptions { + pub(crate) fn from_derive_input(input: &syn::DeriveInput) -> Result<Self, TokenStream> { + match <Self as FromDeriveInput>::from_derive_input(input) { + Ok(v) => Ok(v), + Err(e) => Err(TokenStream::from(e.write_errors())), + } + } + + pub(crate) fn get_serde_with_path(&self) -> Path { + self.alt_crate_path + .clone() + .unwrap_or_else(|| syn::parse_str("::serde_with").unwrap()) + } +} + +// Inspired by https://github.com/serde-rs/serde/blob/fb2fe409c8f7ad6c95e3096e5e9ede865c8cfb49/serde_derive/src/de.rs#L3120 +// Serde is also licensed Apache 2 + MIT +pub(crate) fn split_with_de_lifetime( + generics: &Generics, +) -> ( + DeImplGenerics<'_>, + TypeGenerics<'_>, + Option<&syn::WhereClause>, +) { + let de_impl_generics = DeImplGenerics(generics); + let (_, ty_generics, where_clause) = generics.split_for_impl(); + (de_impl_generics, ty_generics, where_clause) +} + +pub(crate) struct DeImplGenerics<'a>(&'a Generics); + +impl<'a> ToTokens for DeImplGenerics<'a> { + fn to_tokens(&self, tokens: &mut TokenStream2) { + let mut generics = self.0.clone(); + generics.params = Some(parse_quote!('de)) + .into_iter() + .chain(generics.params) + .collect(); + let (impl_generics, _, _) = generics.split_for_impl(); + impl_generics.to_tokens(tokens); + } +} |