mirror of
https://github.com/async-rs/async-std.git
synced 2025-04-01 05:56:41 +00:00
Merge pull request #1030 from joshtriplett/file-eof-should-not-be-permanent
Fix file EOF to not be permanent: reading again should give new data
This commit is contained in:
commit
c6b2128ccd
1 changed files with 45 additions and 4 deletions
|
@ -670,14 +670,19 @@ impl LockGuard<State> {
|
|||
|
||||
match self.mode {
|
||||
Mode::Idle => {}
|
||||
Mode::Reading(0) if self.cache.is_empty() => {
|
||||
// If the cache is empty in reading mode, the last operation didn't read any bytes,
|
||||
// which indicates that it reached the end of the file. In this case we need to
|
||||
// reset the mode to idle so that next time we try to read again, since the file
|
||||
// may grow after the first EOF.
|
||||
self.mode = Mode::Idle;
|
||||
return Poll::Ready(Ok(0));
|
||||
}
|
||||
Mode::Reading(start) => {
|
||||
// How many bytes in the cache are available for reading.
|
||||
let available = self.cache.len() - start;
|
||||
|
||||
// If there is cached unconsumed data or if the cache is empty, we can read from
|
||||
// it. Empty cache in reading mode indicates that the last operation didn't read
|
||||
// any bytes, i.e. it reached the end of the file.
|
||||
if available > 0 || self.cache.is_empty() {
|
||||
if available > 0 {
|
||||
// Copy data from the cache into the buffer.
|
||||
let n = cmp::min(available, buf.len());
|
||||
buf[..n].copy_from_slice(&self.cache[start..(start + n)]);
|
||||
|
@ -913,4 +918,40 @@ mod tests {
|
|||
assert_eq!(format!("{}", expect), format!("{}", actual));
|
||||
})
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn file_eof_is_not_permanent() -> crate::io::Result<()> {
|
||||
let tempdir = tempfile::Builder::new()
|
||||
.prefix("async-std-file-eof-test")
|
||||
.tempdir()?;
|
||||
let path = tempdir.path().join("testfile");
|
||||
|
||||
crate::task::block_on(async {
|
||||
let mut file_w = File::create(&path).await?;
|
||||
let mut file_r = File::open(&path).await?;
|
||||
|
||||
file_w.write_all(b"data").await?;
|
||||
file_w.flush().await?;
|
||||
|
||||
let mut buf = [0u8; 4];
|
||||
let mut len = file_r.read(&mut buf).await?;
|
||||
assert_eq!(len, 4);
|
||||
assert_eq!(&buf, b"data");
|
||||
|
||||
len = file_r.read(&mut buf).await?;
|
||||
assert_eq!(len, 0);
|
||||
|
||||
file_w.write_all(b"more").await?;
|
||||
file_w.flush().await?;
|
||||
|
||||
len = file_r.read(&mut buf).await?;
|
||||
assert_eq!(len, 4);
|
||||
assert_eq!(&buf, b"more");
|
||||
|
||||
len = file_r.read(&mut buf).await?;
|
||||
assert_eq!(len, 0);
|
||||
|
||||
Ok(())
|
||||
})
|
||||
}
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue