rust-libp2p/transports/webrtc/src/tokio/substream/framed_dc.rs

// Copyright 2022 Parity Technologies (UK) Ltd.
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use asynchronous_codec::Framed;
use tokio_util::compat::Compat;
use tokio_util::compat::TokioAsyncReadCompatExt;
use webrtc::data::data_channel::{DataChannel, PollDataChannel};

use std::sync::Arc;

use super::{MAX_DATA_LEN, MAX_MSG_LEN, VARINT_LEN};
use crate::message_proto::Message;

pub type FramedDc = Framed<Compat<PollDataChannel>, prost_codec::Codec<Message>>;

pub fn new(data_channel: Arc<DataChannel>) -> FramedDc {
    let mut inner = PollDataChannel::new(data_channel);
    inner.set_read_buf_capacity(MAX_MSG_LEN);

    let mut framed = Framed::new(
        inner.compat(),
        prost_codec::Codec::new(MAX_MSG_LEN - VARINT_LEN),
    );
    // If not set, `Framed` buffers up to 131kB of data before sending, which leads to "outbound
    // packet larger than maximum message size" error in webrtc-rs.
    framed.set_send_high_water_mark(MAX_DATA_LEN);
    framed
}