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mod decode;
mod encode;

use self::decode::{Decode, DecodeContext};
use self::encode::{Encode, EncodeContext};
use crate::ast::WebidlBindings;
use std::io;

/// Encode the given Web IDL bindings section into the given write-able.
pub fn encode<W>(
    section: &WebidlBindings,
    indices: &walrus::IdsToIndices,
    into: &mut W,
) -> io::Result<()>
where
    W: io::Write,
{
    let cx = &mut EncodeContext::new(indices);
    section.encode(cx, into)
}

/// Decode the Web IDL bindings custom section data from the given input stream.
///
/// This does *not* parse the custom section discriminant and "webidl-bindings"
/// custom section name, just the inner data.
pub fn decode(ids: &walrus::IndicesToIds, from: &[u8]) -> Result<WebidlBindings, failure::Error> {
    let mut cx = DecodeContext::new(ids);
    let mut from = from;
    WebidlBindings::decode(&mut cx, &mut from)?;
    Ok(cx.webidl_bindings)
}

/// Callback for `walrus::ModuleConfig::on_parse` to parse the webidl bindings
/// custom section if one is found.
pub fn on_parse(
    module: &mut walrus::Module,
    ids: &walrus::IndicesToIds,
) -> Result<(), failure::Error> {
    let section = match module.customs.remove_raw("webidl-bindings") {
        Some(s) => s,
        None => return Ok(()),
    };
    let bindings = decode(ids, &section.data)?;
    module.customs.add(bindings);
    Ok(())
}