fmmap 0.5.0

use pin_project_lite::pin_project;
use smol::io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, Cursor, SeekFrom};
use std::{
  fmt::{Debug, Formatter},
  pin::Pin,
  task::{Context, Poll},
};

declare_and_impl_basic_writer!();

impl AsyncRead for AsyncMmapFileWriter<'_> {
  fn poll_read(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    buf: &mut [u8],
  ) -> Poll<std::io::Result<usize>> {
    self.project().w.poll_read(cx, buf)
  }
}

impl AsyncBufRead for AsyncMmapFileWriter<'_> {
  fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<&[u8]>> {
    self.project().w.poll_fill_buf(cx)
  }

  fn consume(self: Pin<&mut Self>, amt: usize) {
    self.project().w.consume(amt)
  }
}

impl AsyncSeek for AsyncMmapFileWriter<'_> {
  fn poll_seek(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    pos: SeekFrom,
  ) -> Poll<std::io::Result<u64>> {
    self.project().w.poll_seek(cx, pos)
  }
}

impl AsyncWrite for AsyncMmapFileWriter<'_> {
  fn poll_write(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>,
    buf: &[u8],
  ) -> Poll<std::io::Result<usize>> {
    self.project().w.poll_write(cx, buf)
  }

  fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
    self.project().w.poll_flush(cx)
  }

  fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
    self.project().w.poll_close(cx)
  }
}

#[cfg(test)]
mod tests {
  use crate::{raw::smol::AsyncMemoryMmapFileMut, smol::AsyncMmapFileMutExt};
  use smol::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt};

  #[smol_potat::test]
  async fn test_writer() {
    let mut file = AsyncMemoryMmapFileMut::from_vec("test.mem", vec![1; 8096]);
    let mut w = file.writer(0).unwrap();
    let _ = format!("{:?}", w);
    assert_eq!(w.len(), 8096);
    assert_eq!(w.offset(), 0);
    let mut buf = [0; 10];
    let n = w.read(&mut buf).await.unwrap();
    assert!(buf[0..n].eq(vec![1; n].as_slice()));
    w.fill_buf().await.unwrap();
    w.consume(8096);
    w.close().await.unwrap();
  }
}