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