diff options
| -rw-r--r-- | src/libstd/io/mod.rs | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs index 797318d95b7..9eb54c2cc00 100644 --- a/src/libstd/io/mod.rs +++ b/src/libstd/io/mod.rs @@ -251,7 +251,6 @@ use crate::cmp; use crate::fmt; -use crate::mem; use crate::memchr; use crate::ops::{Deref, DerefMut}; use crate::ptr; @@ -1435,12 +1434,15 @@ pub trait Write { /// ``` #[unstable(feature = "write_all_vectored", issue = "70436")] fn write_all_vectored(&mut self, mut bufs: &mut [IoSlice<'_>]) -> Result<()> { + // Guarantee that bufs is empty if it contains no data, + // to avoid calling write_vectored if there is no data to be written. + bufs = IoSlice::advance(bufs, 0); while !bufs.is_empty() { match self.write_vectored(bufs) { Ok(0) => { return Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer")); } - Ok(n) => bufs = IoSlice::advance(mem::take(&mut bufs), n), + Ok(n) => bufs = IoSlice::advance(bufs, n), Err(ref e) if e.kind() == ErrorKind::Interrupted => {} Err(e) => return Err(e), } @@ -2958,6 +2960,7 @@ mod tests { #[rustfmt::skip] // Becomes unreadable otherwise. let tests: Vec<(_, &'static [u8])> = vec![ (vec![], &[]), + (vec![IoSlice::new(&[]), IoSlice::new(&[])], &[]), (vec![IoSlice::new(&[1])], &[1]), (vec![IoSlice::new(&[1, 2])], &[1, 2]), (vec![IoSlice::new(&[1, 2, 3])], &[1, 2, 3]), |