oxc/napi/parser/src/lib.rs

#![allow(
    clippy::needless_pass_by_value // Napi value need to be passed as value
)]

mod convert;
mod types;

use napi::{bindgen_prelude::AsyncTask, Task};
use napi_derive::napi;

use oxc::{
    allocator::Allocator,
    ast::CommentKind,
    parser::{ParseOptions, Parser, ParserReturn},
    span::SourceType,
};
use oxc_napi::Error;

pub use crate::types::{Comment, EcmaScriptModule, ParseResult, ParserOptions};

fn get_source_type(filename: &str, options: &ParserOptions) -> SourceType {
    match options.lang.as_deref() {
        Some("js") => SourceType::mjs(),
        Some("jsx") => SourceType::jsx(),
        Some("ts") => SourceType::ts(),
        Some("tsx") => SourceType::tsx(),
        _ => {
            let mut source_type = SourceType::from_path(filename).unwrap_or_default();
            // Force `script` or `module`
            match options.source_type.as_deref() {
                Some("script") => source_type = source_type.with_script(true),
                Some("module") => source_type = source_type.with_module(true),
                _ => {}
            }
            source_type
        }
    }
}

fn parse<'a>(
    allocator: &'a Allocator,
    source_type: SourceType,
    source_text: &'a str,
    options: &ParserOptions,
) -> ParserReturn<'a> {
    Parser::new(allocator, source_text, source_type)
        .with_options(ParseOptions {
            preserve_parens: options.preserve_parens.unwrap_or(true),
            ..ParseOptions::default()
        })
        .parse()
}

/// Parse without returning anything.
///
/// This is for benchmark purposes such as measuring napi communication overhead.
#[napi]
pub fn parse_without_return(filename: String, source_text: String, options: Option<ParserOptions>) {
    let options = options.unwrap_or_default();
    let allocator = Allocator::default();
    let source_type = get_source_type(&filename, &options);
    parse(&allocator, source_type, &source_text, &options);
}

fn parse_with_return(filename: &str, source_text: &str, options: &ParserOptions) -> ParseResult {
    let allocator = Allocator::default();
    let source_type = get_source_type(filename, options);
    let ret = parse(&allocator, source_type, source_text, options);
    let program = serde_json::to_string(&ret.program).unwrap();

    let errors = ret.errors.into_iter().map(Error::from).collect::<Vec<_>>();

    let comments = ret
        .program
        .comments
        .iter()
        .map(|comment| Comment {
            r#type: match comment.kind {
                CommentKind::Line => String::from("Line"),
                CommentKind::Block => String::from("Block"),
            },
            value: comment.content_span().source_text(source_text).to_string(),
            start: comment.span.start,
            end: comment.span.end,
        })
        .collect::<Vec<Comment>>();

    let module = EcmaScriptModule::from(&ret.module_record);
    ParseResult { program, module, comments, errors }
}

/// Parse synchronously.
#[napi]
pub fn parse_sync(
    filename: String,
    source_text: String,
    options: Option<ParserOptions>,
) -> ParseResult {
    let options = options.unwrap_or_default();
    parse_with_return(&filename, &source_text, &options)
}

pub struct ResolveTask {
    filename: String,
    source_text: String,
    options: ParserOptions,
}

#[napi]
impl Task for ResolveTask {
    type JsValue = ParseResult;
    type Output = ParseResult;

    fn compute(&mut self) -> napi::Result<Self::Output> {
        Ok(parse_with_return(&self.filename, &self.source_text, &self.options))
    }

    fn resolve(&mut self, _: napi::Env, result: Self::Output) -> napi::Result<Self::JsValue> {
        Ok(result)
    }
}

/// Parse asynchronously.
///
/// Note: This function can be slower than `parseSync` due to the overhead of spawning a thread.
#[napi]
pub fn parse_async(
    filename: String,
    source_text: String,
    options: Option<ParserOptions>,
) -> AsyncTask<ResolveTask> {
    let options = options.unwrap_or_default();
    AsyncTask::new(ResolveTask { filename, source_text, options })
}