diff options
| -rw-r--r-- | library/std/src/sys/windows/mod.rs | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/library/std/src/sys/windows/mod.rs b/library/std/src/sys/windows/mod.rs index 2c832aa75fd..4e9d408291d 100644 --- a/library/std/src/sys/windows/mod.rs +++ b/library/std/src/sys/windows/mod.rs @@ -156,7 +156,13 @@ pub fn unrolled_find_u16s(needle: u16, haystack: &[u16]) -> Option<usize> { pub fn to_u16s<S: AsRef<OsStr>>(s: S) -> crate::io::Result<Vec<u16>> { fn inner(s: &OsStr) -> crate::io::Result<Vec<u16>> { - let mut maybe_result: Vec<u16> = s.encode_wide().collect(); + // Most paths are ASCII, so reserve capacity for as much as there are bytes + // in the OsStr plus one for the null-terminating character. We are not + // wasting bytes here as paths created by this function are primarily used + // in an ephemeral fashion. + let mut maybe_result = Vec::with_capacity(s.len() + 1); + maybe_result.extend(s.encode_wide()); + if unrolled_find_u16s(0, &maybe_result).is_some() { return Err(crate::io::const_io_error!( ErrorKind::InvalidInput, |