minisql/proto/src/reader/oneway.rs
2023-12-23 01:28:30 +01:00

41 lines
1.2 KiB
Rust

use crate::message::proto_message::ProtoMessage;
use crate::reader::errors::ProtoReadError;
use crate::reader::protoreader::ProtoReader;
use crate::reader::utils::AsyncPeek;
use async_trait::async_trait;
use tokio::io::{AsyncBufRead, AsyncReadExt};
#[async_trait]
pub trait OneWayProtoReader<T>
where
T: ProtoMessage,
{
async fn read_proto(&mut self) -> Result<T, ProtoReadError>;
}
#[async_trait]
impl<R, T> OneWayProtoReader<T> for ProtoReader<R>
where
R: AsyncBufRead + AsyncPeek + Unpin + Send,
T: ProtoMessage,
{
async fn read_proto(&mut self) -> Result<T, ProtoReadError> {
let variant = self.inner.read_u8().await?;
let length = self.inner.read_i32().await?;
if length < 4 {
return Err(ProtoReadError::InvalidLength(length));
}
if length > self.msg_len_limit {
return Err(ProtoReadError::LengthOverflow {
limit: self.msg_len_limit as usize,
actual: length as usize,
});
}
let mut data = vec![0u8; (length - 4) as usize];
self.inner.read_exact(&mut data).await?;
Ok(T::deserialize(variant, &data)?)
}
}