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denoland-deno/cli/napi_sym/lib.rs
Divy Srivastava 0b016a7fb8
feat(npm): implement Node API (#13633)
This PR implements the NAPI for loading native modules into Deno. 

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: DjDeveloper <43033058+DjDeveloperr@users.noreply.github.com>
Co-authored-by: Ryan Dahl <ry@tinyclouds.org>
2022-10-05 19:36:44 +05:30

46 lines
1.3 KiB
Rust

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
use proc_macro::TokenStream;
use quote::quote;
use serde::Deserialize;
static NAPI_EXPORTS: &str =
include_str!("../../tools/napi/symbol_exports.json");
#[derive(Deserialize)]
struct SymbolExports {
pub symbols: Vec<String>,
}
#[proc_macro_attribute]
pub fn napi_sym(_attr: TokenStream, item: TokenStream) -> TokenStream {
let func = syn::parse::<syn::ItemFn>(item).expect("expected a function");
let exports: SymbolExports =
serde_json::from_str(NAPI_EXPORTS).expect("failed to parse exports");
let name = &func.sig.ident;
assert!(
exports.symbols.contains(&name.to_string()),
"tools/napi/symbol_exports.json is out of sync!"
);
let block = &func.block;
let inputs = &func.sig.inputs;
let output = &func.sig.output;
let ret_ty = match output {
syn::ReturnType::Default => panic!("expected a return type"),
syn::ReturnType::Type(_, ty) => quote! { #ty },
};
TokenStream::from(quote! {
// SAFETY: it's an NAPI function.
#[no_mangle]
pub unsafe extern "C" fn #name(#inputs) -> napi_status {
let mut inner = || -> #ret_ty {
#block
};
inner()
.map(|_| napi_ok)
.unwrap_or_else(|e| e.into())
}
})
}