diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index 458c3bb036d8d..6461c90de6c19 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -7,7 +7,7 @@ use crate::fmt; use crate::fs; use crate::io; use crate::marker::PhantomData; -use crate::mem::forget; +use crate::mem::{forget, ManuallyDrop}; use crate::ptr; use crate::sys; use crate::sys::cvt; @@ -91,7 +91,7 @@ pub struct OwnedHandle { #[repr(transparent)] #[stable(feature = "io_safety", since = "1.63.0")] #[derive(Debug)] -pub struct HandleOrNull(OwnedHandle); +pub struct HandleOrNull(RawHandle); /// FFI type for handles in return values or out parameters, where `INVALID_HANDLE_VALUE` is used /// as a sentry value to indicate errors, such as in the return value of `CreateFileW`. This uses @@ -110,7 +110,7 @@ pub struct HandleOrNull(OwnedHandle); #[repr(transparent)] #[stable(feature = "io_safety", since = "1.63.0")] #[derive(Debug)] -pub struct HandleOrInvalid(OwnedHandle); +pub struct HandleOrInvalid(RawHandle); // The Windows [`HANDLE`] type may be transferred across and shared between // thread boundaries (despite containing a `*mut void`, which in general isn't @@ -163,15 +163,24 @@ impl TryFrom for OwnedHandle { #[inline] fn try_from(handle_or_null: HandleOrNull) -> Result { - let owned_handle = handle_or_null.0; - if owned_handle.handle.is_null() { - // Don't call `CloseHandle`; it'd be harmless, except that it could - // overwrite the `GetLastError` error. - forget(owned_handle); - - Err(NullHandleError(())) + let handle_or_null = ManuallyDrop::new(handle_or_null); + if handle_or_null.is_valid() { + // SAFETY: The handle is not null. + Ok(unsafe { OwnedHandle::from_raw_handle(handle_or_null.0) }) } else { - Ok(owned_handle) + Err(NullHandleError(())) + } + } +} + +#[stable(feature = "io_safety", since = "1.63.0")] +impl Drop for HandleOrNull { + #[inline] + fn drop(&mut self) { + if self.is_valid() { + unsafe { + let _ = sys::c::CloseHandle(self.0); + } } } } @@ -232,15 +241,24 @@ impl TryFrom for OwnedHandle { #[inline] fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { - let owned_handle = handle_or_invalid.0; - if owned_handle.handle == sys::c::INVALID_HANDLE_VALUE { - // Don't call `CloseHandle`; it'd be harmless, except that it could - // overwrite the `GetLastError` error. - forget(owned_handle); - - Err(InvalidHandleError(())) + let handle_or_invalid = ManuallyDrop::new(handle_or_invalid); + if handle_or_invalid.is_valid() { + // SAFETY: The handle is not invalid. + Ok(unsafe { OwnedHandle::from_raw_handle(handle_or_invalid.0) }) } else { - Ok(owned_handle) + Err(InvalidHandleError(())) + } + } +} + +#[stable(feature = "io_safety", since = "1.63.0")] +impl Drop for HandleOrInvalid { + #[inline] + fn drop(&mut self) { + if self.is_valid() { + unsafe { + let _ = sys::c::CloseHandle(self.0); + } } } } @@ -333,7 +351,11 @@ impl HandleOrNull { #[stable(feature = "io_safety", since = "1.63.0")] #[inline] pub unsafe fn from_raw_handle(handle: RawHandle) -> Self { - Self(OwnedHandle::from_raw_handle(handle)) + Self(handle) + } + + fn is_valid(&self) -> bool { + !self.0.is_null() } } @@ -356,7 +378,11 @@ impl HandleOrInvalid { #[stable(feature = "io_safety", since = "1.63.0")] #[inline] pub unsafe fn from_raw_handle(handle: RawHandle) -> Self { - Self(OwnedHandle::from_raw_handle(handle)) + Self(handle) + } + + fn is_valid(&self) -> bool { + self.0 != sys::c::INVALID_HANDLE_VALUE } }