build.rs

use anyhow::Result;
use std::{env, fs, io::Write, path::PathBuf};

use js_component_bindgen::{generate_types, source::wit_parser::Resolve};

fn main() -> Result<()> {
    // This will ensure that the build script will always run
    println!("cargo:rerun-if-changed=NULL");
    if env::var("PREVIEW2_SHIM_TYPES").is_ok() {
        for world in ["wasi:http/proxy", "wasi:cli/command"] {
            let name = world.replace([':', '/'], "-");
            let preview2_wit_path = "./test/fixtures/wit";

            let mut resolve = Resolve::default();
            let (_, _) = resolve.push_dir(&PathBuf::from(preview2_wit_path))?;

            let world_parts: Vec<&str> = world.split('/').collect();
            let world_name = world_parts[1];

            let preview2 = *resolve
                .package_names
                .iter()
                .find(|(name, _)| name.interface_id(world_name) == world)
                .unwrap()
                .1;

            let world = resolve.select_world(preview2, Some(world_name))?;

            let opts = js_component_bindgen::TranspileOpts {
                name: "component".to_string(),
                no_typescript: false,
                no_nodejs_compat: false,
                instantiation: false,
                map: None,
                tla_compat: false,
                valid_lifting_optimization: false,
                base64_cutoff: 0,
                tracing: false,
            };

            let files = generate_types(name, resolve, world, opts)?;

            if !fs::metadata("./packages/preview2-shim/types").is_err() {
                fs::remove_dir_all("./packages/preview2-shim/types")?;
            }
            for (filename, contents) in files.iter() {
                let outfile = PathBuf::from("./packages/preview2-shim/types").join(filename);
                fs::create_dir_all(outfile.parent().unwrap()).unwrap();
                let mut file = fs::File::create(outfile).unwrap();
                file.write_all(contents).unwrap();
            }
        }
    }
    Ok(())
}