moq-lite 0.15.4

Media over QUIC - Transport (Lite)
Documentation 
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use bytes::{Buf, BufMut};

use crate::coding::{Decode, DecodeError, Encode, EncodeError, Sizer};

use super::Version;

/// A trait for IETF messages that are automatically size-prefixed during encoding/decoding.
///
/// IETF messages use a u16 size prefix and have a message type ID for control stream dispatch.
pub trait Message: Sized + std::fmt::Debug {
	const ID: u64;

	/// Encode this message body (without size prefix).
	fn encode_msg<W: BufMut>(&self, w: &mut W, version: Version) -> Result<(), EncodeError>;

	/// Decode a message body (without size prefix).
	fn decode_msg<B: Buf>(buf: &mut B, version: Version) -> Result<Self, DecodeError>;
}

impl<T: Message> Encode<Version> for T {
	fn encode<W: BufMut>(&self, w: &mut W, version: Version) -> Result<(), EncodeError> {
		let mut sizer = Sizer::default();
		self.encode_msg(&mut sizer, version)?;
		let size: u16 = sizer.size.try_into().map_err(|_| EncodeError::TooLarge)?;
		size.encode(w, version)?;
		self.encode_msg(w, version)
	}
}

impl<T: Message> Decode<Version> for T {
	fn decode<B: Buf>(buf: &mut B, version: Version) -> Result<Self, DecodeError> {
		let size = u16::decode(buf, version)? as usize;
		let mut limited = buf.take(size);
		let result = Self::decode_msg(&mut limited, version)?;
		if limited.remaining() > 0 {
			return Err(DecodeError::Long);
		}
		Ok(result)
	}
}