Function compress_bytecode

llrt_core/build.rs:226–271

(dictionary_path: String, source_files: Vec<String>)

    generate_compression_dictionary(&dictionary_path, &source_files)?;

    let mut total_size = 0;
    let tmp_dir = env::temp_dir();

    for filename in source_files {
        info!("Compressing {}...", filename);

        let tmp_filename = tmp_dir
            .join(uuid::Uuid::new_v4().to_string())
            .to_string_lossy()
            .to_string();

        fs::copy(&filename, &tmp_filename)?;

        let uncompressed_file_size = PathBuf::from(&filename).metadata()?.len() as u32;

        let output = Command::new("zstd")
            .args([
                "--ultra",
                "-22",
                "-f",
                "-D",
                &dictionary_path,
                &tmp_filename,
                "-o",
                &filename,
            ])
            .output()?;

        if !output.status.success() {
            return Err(io::Error::other("Failed to compress file"));
        }

        let bytes = fs::read(&filename)?;
        let compressed = add_bytecode_header(bytes, Some(uncompressed_file_size));
        fs::write(&filename, compressed)?;

        let compressed_file_size = PathBuf::from(&filename).metadata().unwrap().len() as usize;

        total_size += compressed_file_size;
    }

    Ok(total_size)
}

fn generate_compression_dictionary(
    dictionary_path: &str,
    source_files: &[String],
) -> Result<(), io::Error> {
    info!("Generating compression dictionary...");