mirror of
https://github.com/hexedtech/jni-toolbox.git
synced 2025-03-17 08:41:32 +01:00
49 lines
1.7 KiB
Rust
49 lines
1.7 KiB
Rust
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use proc_macro2::{Span, TokenStream};
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use quote::ToTokens;
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use syn::{ReturnType, Type};
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#[derive(Clone)]
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pub(crate) struct ReturnOptions {
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pub(crate) ty: Option<Box<Type>>,
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pub(crate) result: bool,
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}
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impl ReturnOptions {
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pub(crate) fn parse_signature(ret: ReturnType) -> Result<Self, syn::Error> {
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match ret {
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syn::ReturnType::Default => Ok(Self { ty: None, result: false }),
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syn::ReturnType::Type(_tok, ty) => match *ty {
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syn::Type::Path(ref path) => {
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let Some(last) = path.path.segments.last() else {
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return Err(syn::Error::new(Span::call_site(), "empty Result type is not valid"));
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};
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if last.ident == "Result" {
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match &last.arguments {
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syn::PathArguments::None => return Err(syn::Error::new(Span::call_site(), "Result without generics is not valid")),
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syn::PathArguments::Parenthesized(_) => return Err(syn::Error::new(Span::call_site(), "Parenthesized Result is not valid")),
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syn::PathArguments::AngleBracketed(ref generics) => for generic in generics.args.iter() {
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match generic {
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syn::GenericArgument::Lifetime(_) => continue,
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syn::GenericArgument::Type(ty) => return Ok(Self { ty: Some(Box::new(ty.clone())), result: true }),
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_ => return Err(syn::Error::new(Span::call_site(), "unexpected type in Result")),
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}
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}
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}
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}
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Ok(Self { ty: Some(Box::new(Type::Path(path.clone()))), result: false })
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},
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_ => Err(syn::Error::new(Span::call_site(), "unsupported return type")),
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},
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}
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}
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pub(crate) fn tokens(self) -> TokenStream {
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match self.ty {
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Some(t) => ReturnType::Type(syn::Token), t).to_token_stream(),
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None => ReturnType::Default.to_token_stream(),
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}
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}
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}
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