fn build_bindings()

in neqo-crypto/build.rs [233:290]
50 lines of code
14 McCabe index (conditional complexity)

fn build_bindings(base: &str, bindings: &Bindings, flags: &[String], gecko: bool) {
    let suffix = if bindings.cplusplus { ".hpp" } else { ".h" };
    let header_path = PathBuf::from(BINDINGS_DIR).join(String::from(base) + suffix);
    let header = header_path.to_str().unwrap();
    let out = PathBuf::from(env::var("OUT_DIR").unwrap()).join(String::from(base) + ".rs");

    println!("cargo:rerun-if-changed={header}");

    let mut builder = Builder::default().header(header);
    builder = builder.generate_comments(false);
    builder = builder.size_t_is_usize(true);

    builder = builder.clang_arg("-v");

    if !gecko {
        builder = builder.clang_arg("-DNO_NSPR_10_SUPPORT");
        if env::consts::OS == "windows" {
            builder = builder.clang_arg("-DWIN");
        } else if env::consts::OS == "macos" {
            builder = builder.clang_arg("-DDARWIN");
        } else if env::consts::OS == "linux" {
            builder = builder.clang_arg("-DLINUX");
        } else if env::consts::OS == "android" {
            builder = builder.clang_arg("-DLINUX");
            builder = builder.clang_arg("-DANDROID");
        }
        if bindings.cplusplus {
            builder = builder.clang_args(&["-x", "c++", "-std=c++14"]);
        }
    }

    builder = builder.clang_args(flags);

    // Apply the configuration.
    for v in &bindings.types {
        builder = builder.allowlist_type(v);
    }
    for v in &bindings.functions {
        builder = builder.allowlist_function(v);
    }
    for v in &bindings.variables {
        builder = builder.allowlist_var(v);
    }
    for v in &bindings.exclude {
        builder = builder.blocklist_item(v);
    }
    for v in &bindings.opaque {
        builder = builder.opaque_type(v);
    }
    for v in &bindings.enums {
        builder = builder.constified_enum_module(v);
    }

    let bindings = builder.generate().expect("unable to generate bindings");
    bindings
        .write_to_file(out)
        .expect("couldn't write bindings");
}