From 703a33673de30572960eb3fe2c36a0f51083d226 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sun, 27 Mar 2022 15:41:13 -0700 Subject: Define a dedicated error type for `HandleOrNull` and `HandleOrInvalid`. Define a `NotHandle` type, that implements `std::error::Error`, and use it as the error type in `HandleOrNull` and `HandleOrInvalid`. --- library/std/src/os/windows/io/handle.rs | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) (limited to 'library/std/src') diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index ee30cc8be6b..1fb448be5de 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -143,17 +143,17 @@ impl BorrowedHandle<'_> { } impl TryFrom for OwnedHandle { - type Error = (); + type Error = NotHandle; #[inline] - fn try_from(handle_or_null: HandleOrNull) -> Result { + 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(()) + Err(NotHandle(())) } else { Ok(owned_handle) } @@ -201,23 +201,37 @@ impl OwnedHandle { } impl TryFrom for OwnedHandle { - type Error = (); + type Error = NotHandle; #[inline] - fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { + fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { let owned_handle = handle_or_invalid.0; if owned_handle.handle == c::INVALID_HANDLE_VALUE { // Don't call `CloseHandle`; it'd be harmless, except that it could // overwrite the `GetLastError` error. forget(owned_handle); - Err(()) + Err(NotHandle(())) } else { Ok(owned_handle) } } } +/// This is the error type used by [`HandleOrInvalid`] and +/// [`HandleOrNull`] when attempting to convert into a handle, +/// to indicate that the value is not a handle. +#[unstable(feature = "io_safety", issue = "87074")] +#[derive(Debug, Copy, Clone, PartialEq, Eq)] +pub struct NotHandle(()); + +#[unstable(feature = "io_safety", issue = "87074")] +impl fmt::Display for NotHandle { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + "the return value of a Windows API call indicated an error".fmt(fmt) + } +} + impl AsRawHandle for BorrowedHandle<'_> { #[inline] fn as_raw_handle(&self) -> RawHandle { -- cgit 1.4.1-3-g733a5 From 5b3023c56420ce55d8b6761ea557fd4d6f579bdf Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sun, 27 Mar 2022 16:53:56 -0700 Subject: Fix an incorrect word in a comment. --- library/std/src/os/windows/io/handle.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'library/std/src') diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index 1fb448be5de..1bed22a4ce5 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -76,7 +76,7 @@ pub struct OwnedHandle { /// `NULL`. This ensures that such FFI calls cannot start using the handle without /// checking for `NULL` first. /// -/// This type concerns any value other than `NULL` to be valid, including `INVALID_HANDLE_VALUE`. +/// This type considers any value other than `NULL` to be valid, including `INVALID_HANDLE_VALUE`. /// This is because APIs that use `NULL` as their sentry value don't treat `INVALID_HANDLE_VALUE` /// as special. /// @@ -96,7 +96,7 @@ pub struct HandleOrNull(OwnedHandle); /// `INVALID_HANDLE_VALUE`. This ensures that such FFI calls cannot start using the handle without /// checking for `INVALID_HANDLE_VALUE` first. /// -/// This type concerns any value other than `INVALID_HANDLE_VALUE` to be valid, including `NULL`. +/// This type considers any value other than `INVALID_HANDLE_VALUE` to be valid, including `NULL`. /// This is because APIs that use `INVALID_HANDLE_VALUE` as their sentry value may return `NULL` /// under `windows_subsystem = "windows"` or other situations where I/O devices are detached. /// -- cgit 1.4.1-3-g733a5 From 67994b77fda81223c9e71f0d476aa849c9be9699 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sun, 27 Mar 2022 16:54:58 -0700 Subject: Move the `Error` impl for `NotHandle` out of platform-independent code. --- library/std/src/os/windows/io/handle.rs | 3 +++ 1 file changed, 3 insertions(+) (limited to 'library/std/src') diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index 1bed22a4ce5..c6b84b6e5d3 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -232,6 +232,9 @@ impl fmt::Display for NotHandle { } } +#[unstable(feature = "io_safety", issue = "87074")] +impl crate::error::Error for NotHandle {} + impl AsRawHandle for BorrowedHandle<'_> { #[inline] fn as_raw_handle(&self) -> RawHandle { -- cgit 1.4.1-3-g733a5 From f934043c179eb2d9c1dda4e7a70284e0d9354c82 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Mon, 28 Mar 2022 10:56:00 -0700 Subject: Split `NotHandle` into `NullHandleError` and `InvalidHandleError`. Also, make the display messages more specific, and remove the `Copy` implementation. --- library/std/src/os/windows/io/handle.rs | 45 +++++++++++++++++++++++---------- 1 file changed, 31 insertions(+), 14 deletions(-) (limited to 'library/std/src') diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index c6b84b6e5d3..e48f630f76e 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -143,17 +143,17 @@ impl BorrowedHandle<'_> { } impl TryFrom for OwnedHandle { - type Error = NotHandle; + type Error = NullHandleError; #[inline] - fn try_from(handle_or_null: HandleOrNull) -> Result { + 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(NotHandle(())) + Err(NullHandleError(())) } else { Ok(owned_handle) } @@ -201,39 +201,56 @@ impl OwnedHandle { } impl TryFrom for OwnedHandle { - type Error = NotHandle; + type Error = InvalidHandleError; #[inline] - fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { + fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { let owned_handle = handle_or_invalid.0; if owned_handle.handle == c::INVALID_HANDLE_VALUE { // Don't call `CloseHandle`; it'd be harmless, except that it could // overwrite the `GetLastError` error. forget(owned_handle); - Err(NotHandle(())) + Err(InvalidHandleError(())) } else { Ok(owned_handle) } } } -/// This is the error type used by [`HandleOrInvalid`] and -/// [`HandleOrNull`] when attempting to convert into a handle, -/// to indicate that the value is not a handle. +/// This is the error type used by [`HandleOrNull`] when attempting to convert +/// into a handle, to indicate that the value is null. #[unstable(feature = "io_safety", issue = "87074")] -#[derive(Debug, Copy, Clone, PartialEq, Eq)] -pub struct NotHandle(()); +#[derive(Debug, Clone, PartialEq, Eq)] +pub struct NullHandleError(()); #[unstable(feature = "io_safety", issue = "87074")] -impl fmt::Display for NotHandle { +impl fmt::Display for NullHandleError { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { - "the return value of a Windows API call indicated an error".fmt(fmt) + "A HandleOrNull could not be converted to a handle because it was null".fmt(fmt) } } #[unstable(feature = "io_safety", issue = "87074")] -impl crate::error::Error for NotHandle {} +impl crate::error::Error for NullHandleError {} + +/// This is the error type used by [`HandleOrInvalid`] when attempting to +/// convert into a handle, to indicate that the value is +/// `INVALID_HANDLE_VALUE`. +#[unstable(feature = "io_safety", issue = "87074")] +#[derive(Debug, Clone, PartialEq, Eq)] +pub struct InvalidHandleError(()); + +#[unstable(feature = "io_safety", issue = "87074")] +impl fmt::Display for InvalidHandleError { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + "A HandleOrInvalid could not be converted to a handle because it was INVALID_HANDLE_VALUE" + .fmt(fmt) + } +} + +#[unstable(feature = "io_safety", issue = "87074")] +impl crate::error::Error for InvalidHandleError {} impl AsRawHandle for BorrowedHandle<'_> { #[inline] -- cgit 1.4.1-3-g733a5 From 890125d73e939cda058cf692c6a3ce927fc0898f Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Wed, 13 Apr 2022 14:32:17 -0700 Subject: Add a comment explaining the `(())` idiom for empty structs. --- library/std/src/os/windows/io/handle.rs | 2 ++ 1 file changed, 2 insertions(+) (limited to 'library/std/src') diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index e48f630f76e..e4de52612ef 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -220,6 +220,7 @@ impl TryFrom for OwnedHandle { /// This is the error type used by [`HandleOrNull`] when attempting to convert /// into a handle, to indicate that the value is null. +// The empty field prevents constructing this, and allows extending it in the future. #[unstable(feature = "io_safety", issue = "87074")] #[derive(Debug, Clone, PartialEq, Eq)] pub struct NullHandleError(()); @@ -237,6 +238,7 @@ impl crate::error::Error for NullHandleError {} /// This is the error type used by [`HandleOrInvalid`] when attempting to /// convert into a handle, to indicate that the value is /// `INVALID_HANDLE_VALUE`. +// The empty field prevents constructing this, and allows extending it in the future. #[unstable(feature = "io_safety", issue = "87074")] #[derive(Debug, Clone, PartialEq, Eq)] pub struct InvalidHandleError(()); -- cgit 1.4.1-3-g733a5