46 lines
1.6 KiB
Rust
46 lines
1.6 KiB
Rust
use std::marker::Unpin;
|
|
use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
|
|
|
|
use super::{hash, verify_checksum, DecodeError, EncodeError};
|
|
|
|
/// Decode a framed message into a `Vec<u8>`.
|
|
///
|
|
/// # Errors
|
|
/// An error may be returned if:
|
|
/// * The given `data` does not contain enough data to parse a length,
|
|
/// * The given `data` does not contain the given length's worth of data,
|
|
/// * The given `data` has a checksum that does not match what we build locally.
|
|
pub async fn try_decode_from(
|
|
readable: &mut (impl AsyncRead + Unpin),
|
|
) -> Result<Vec<u8>, DecodeError> {
|
|
let len = readable.read_u32().await?;
|
|
|
|
let mut data = Vec::with_capacity(len as usize);
|
|
readable.read_exact(&mut data[..]).await?;
|
|
|
|
let content = verify_checksum(&data[..])?;
|
|
|
|
// Note: Optimizing this isn't *too* practical, we could probably pop the first 32 bytes off
|
|
// the front of the Vec, but it might not even be worth it as opposed to one reallocation.
|
|
Ok(content.to_vec())
|
|
}
|
|
|
|
/// Encode a &[u8] into a framed message
|
|
///
|
|
/// # Errors
|
|
/// An error may be returned if:
|
|
/// * The given `data` is more than [`u32::MAX`] bytes. This is a constraint on a protocol level.
|
|
/// * The resulting data was unable to be written to the given `writable`.
|
|
pub async fn try_encode_to(
|
|
data: &[u8],
|
|
writable: &mut (impl AsyncWrite + Unpin),
|
|
) -> Result<(), EncodeError> {
|
|
let hash = hash(data);
|
|
let len = u32::try_from(hash.len() + data.len())
|
|
.map_err(|_| EncodeError::InputTooLarge(hash.len() + data.len()))?;
|
|
writable.write_u32(len).await?;
|
|
writable.write_all(&hash[..]).await?;
|
|
writable.write_all(data).await?;
|
|
Ok(())
|
|
}
|