sheave_core/writers/chunk_data.rs
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use std::{
future::Future,
io::Result as IOResult,
pin::{
Pin,
pin
},
task::{
Context as FutureContext,
Poll
}
};
use futures::ready;
use tokio::io::AsyncWrite;
use crate::{
messages::{
ChunkSize,
headers::{
BasicHeader,
MessageFormat
}
},
writers::write_basic_header
};
#[doc(hidden)]
#[derive(Debug)]
pub struct ChunkDataWriter<'a, W: AsyncWrite> {
writer: Pin<&'a mut W>,
chunk_id: u16,
chunk_size: ChunkSize,
chunk_data: &'a [u8],
}
#[doc(hidden)]
impl<W: AsyncWrite> Future for ChunkDataWriter<'_, W> {
type Output = IOResult<()>;
fn poll(mut self: Pin<&mut Self>, cx: &mut FutureContext<'_>) -> Poll<Self::Output> {
let chunk_size = self.chunk_size.get_chunk_size();
let mut chunks = self.chunk_data.chunks(chunk_size as usize);
while let Some(chunk) = chunks.next() {
ready!(self.writer.as_mut().poll_write(cx, chunk))?;
if chunks.size_hint().0 >= 1 {
let basic_header = BasicHeader::new(MessageFormat::Continue, self.chunk_id);
ready!(pin!(write_basic_header(self.writer.as_mut(), &basic_header)).poll(cx))?;
}
}
Poll::Ready(Ok(()))
}
}
/// Writes a chunk data into streams.
///
/// If a chunk data exceeds specified chunk size, continue headers is inserted between chunk data per chunk size.
/// Note the message length doesn't count their headers.
///
/// # Examples
///
/// ```rust
/// use std::{
/// io::Result as IOResult,
/// pin::{
/// Pin,
/// pin
/// }
/// };
/// use rand::{
/// Fill,
/// thread_rng
/// };
/// use sheave_core::{
/// messages::{
/// ChunkSize,
/// headers::MessageFormat
/// },
/// writers::write_chunk_data
/// };
///
/// #[tokio::main]
/// async fn main() -> IOResult<()> {
/// // When it's just one chunk.
/// let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
/// let mut chunk_data: [u8; 128] = [0; 128];
/// chunk_data.try_fill(&mut thread_rng()).unwrap();
/// write_chunk_data(writer.as_mut(), 2, ChunkSize::default(), &chunk_data).await?;
/// assert_eq!(128, writer.len());
///
/// // When it requires the one byte header.
/// let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
/// let mut chunk_data: [u8; 256] = [0; 256];
/// chunk_data.try_fill(&mut thread_rng()).unwrap();
/// write_chunk_data(writer.as_mut(), 2, ChunkSize::default(), &chunk_data).await?;
/// assert_eq!(257, writer.len());
/// let message_format: MessageFormat = (writer[128] >> 6).into();
/// assert_eq!(MessageFormat::Continue, message_format);
/// let chunk_id = writer[128] << 2 >> 2;
/// assert_eq!(2, chunk_id);
///
/// // When it requires the two bytes header.
/// let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
/// let mut chunk_data: [u8; 256] = [0; 256];
/// chunk_data.try_fill(&mut thread_rng()).unwrap();
/// write_chunk_data(writer.as_mut(), 64, ChunkSize::default(), &chunk_data).await?;
/// assert_eq!(258, writer.len());
/// let message_format: MessageFormat = (writer[128] >> 6).into();
/// assert_eq!(MessageFormat::Continue, message_format);
/// assert_eq!(0, writer[128] << 2 >> 2);
/// let chunk_id = writer[129];
/// assert_eq!(64, chunk_id + 64);
///
/// // When it requires the three bytes header.
/// let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
/// let mut chunk_data: [u8; 256] = [0; 256];
/// chunk_data.try_fill(&mut thread_rng()).unwrap();
/// write_chunk_data(writer.as_mut(), 320, ChunkSize::default(), &chunk_data).await?;
/// assert_eq!(259, writer.len());
/// let message_format: MessageFormat = (writer[128] >> 6).into();
/// assert_eq!(MessageFormat::Continue, message_format);
/// assert_eq!(1, writer[128] << 2 >> 2);
/// let mut chunk_id_bytes: [u8; 2] = [0; 2];
/// chunk_id_bytes.copy_from_slice(&writer[129..131]);
/// let chunk_id = u16::from_le_bytes(chunk_id_bytes);
/// assert_eq!(320, chunk_id + 64);
///
/// Ok(())
/// }
/// ```
pub fn write_chunk_data<'a, W: AsyncWrite>(writer: Pin<&'a mut W>, chunk_id: u16, chunk_size: ChunkSize, chunk_data: &'a [u8]) -> ChunkDataWriter<'a, W> {
ChunkDataWriter { writer, chunk_id, chunk_size, chunk_data }
}
#[cfg(test)]
mod tests {
use std::pin::pin;
use rand::{
Fill,
thread_rng
};
use super::*;
#[tokio::test]
async fn write_one_chunk() {
let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
let mut chunk_data: [u8; 128] = [0; 128];
chunk_data.try_fill(&mut thread_rng()).unwrap();
let result = write_chunk_data(writer.as_mut(), 2, ChunkSize::default(), &chunk_data).await;
assert!(result.is_ok());
assert_eq!(128, writer.len())
}
#[tokio::test]
async fn write_with_one_byte_header() {
let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
let mut chunk_data: [u8; 256] = [0; 256];
chunk_data.try_fill(&mut thread_rng()).unwrap();
let result = write_chunk_data(writer.as_mut(), 2, ChunkSize::default(), &chunk_data).await;
assert!(result.is_ok());
assert_eq!(257, writer.len())
}
#[tokio::test]
async fn write_with_two_bytes_header() {
let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
let mut chunk_data: [u8; 256] = [0; 256];
chunk_data.try_fill(&mut thread_rng()).unwrap();
let result = write_chunk_data(writer.as_mut(), 64, ChunkSize::default(), &chunk_data).await;
assert!(result.is_ok());
assert_eq!(258, writer.len())
}
#[tokio::test]
async fn write_with_three_bytes_header() {
let mut writer: Pin<&mut Vec<u8>> = pin!(Vec::new());
let mut chunk_data: [u8; 256] = [0; 256];
chunk_data.try_fill(&mut thread_rng()).unwrap();
let result = write_chunk_data(writer.as_mut(), 320, ChunkSize::default(), &chunk_data).await;
assert!(result.is_ok());
assert_eq!(259, writer.len());
}
}