sails-macros-core 1.0.1

Implementations of procedural macros for the Sails framework
Documentation 
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use crate::shared;
use args::ExportArgs;
use proc_macro_error::abort;
use proc_macro2::{Span, TokenStream};
use syn::{Attribute, ImplItemFn, parse::Parse, spanned::Spanned};

mod args;

pub fn export(attrs: TokenStream, impl_item_fn_tokens: TokenStream) -> TokenStream {
    let fn_impl: ImplItemFn = syn::parse2::<ImplItemFn>(impl_item_fn_tokens.clone())
        .unwrap_or_else(|err| {
            abort!(
                err.span(),
                "`export` attribute can be applied to methods only: {}",
                err
            )
        });
    ensure_pub_visibility(&fn_impl);
    ensure_single_export_or_route_on_impl(&fn_impl);
    let args = syn::parse2::<ExportArgs>(attrs)
        .unwrap_or_else(|_| abort!(fn_impl.span(), "`export` attribute cannot be parsed"));
    ensure_returns_result_with_unwrap_result(fn_impl, args);
    impl_item_fn_tokens
}

fn ensure_pub_visibility(fn_impl: &ImplItemFn) {
    match fn_impl.vis {
        syn::Visibility::Public(_) => (),
        _ => abort!(
            fn_impl.span(),
            "`export` attribute can be applied to public methods only"
        ),
    }
}

pub(crate) fn ensure_single_export_or_route_on_impl(fn_impl: &ImplItemFn) {
    let attr_export = fn_impl.attrs.iter().find(|attr| {
        attr.meta
            .path()
            .segments
            .last()
            .map(|s| s.ident == "export")
            .unwrap_or(false)
    });
    if attr_export.is_some() {
        abort!(
            fn_impl,
            "multiple `export` attributes on the same method are not allowed",
        )
    }
}

fn ensure_returns_result_with_unwrap_result(fn_impl: ImplItemFn, args: ExportArgs) {
    // ensure Result type is returned if unwrap_result is set to true
    _ = shared::unwrap_result_type(&fn_impl.sig, args.unwrap_result());
}

pub(crate) fn parse_export_args(attrs: &[Attribute]) -> Option<(ExportArgs, Span)> {
    let mut attrs = attrs
        .iter()
        .filter_map(|attr| parse_attr(attr).map(|args| (args, attr.meta.span())));
    let export = attrs.next();
    if let Some((_, span)) = attrs.next() {
        abort!(
            span,
            "multiple `export` attributes are not allowed for the same method"
        )
    }
    export
}

pub(crate) fn parse_attr(attr: &Attribute) -> Option<ExportArgs> {
    if attr
        .path()
        .segments
        .last()
        .is_some_and(|s| s.ident == "export")
    {
        if let Ok(list) = attr.meta.require_list() {
            let args = list
                .parse_args_with(ExportArgs::parse)
                .unwrap_or_else(|err| {
                    abort!(err.span(), "`export` attribute cannot be parsed: {}", err)
                });
            Some(args)
        } else {
            Some(ExportArgs::default())
        }
    } else {
        None
    }
}