Messages in this thread Patch in this message | | | From | Miguel Ojeda <> | Subject | [PATCH v1 10/28] rust: error: add `From` implementations for `Error` | Date | Thu, 10 Nov 2022 17:41:22 +0100 |
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From: Wedson Almeida Filho <wedsonaf@gmail.com>
Add a set of `From` implementations for the `Error` kernel type.
These implementations allow to easily convert from standard Rust error types to the usual kernel errors based on one of the `E*` integer codes.
On top of that, the question mark Rust operator (`?`) implicitly performs a conversion on the error value using the `From` trait when propagating. Thus it is extra convenient to use.
For instance, a kernel function that needs to convert a `i64` into a `i32` and to bubble up the error as a kernel error may write:
fn f(x: i64) -> Result<...> { ... let y = i32::try_from(x)?; ... }
which will transform the `TryFromIntError` into an `Err(EINVAL)`.
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Nándor István Krácser <bonifaido@gmail.com> Signed-off-by: Nándor István Krácser <bonifaido@gmail.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> [Reworded, adapted for upstream and applied latest changes] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> --- rust/kernel/error.rs | 45 +++++++++++++++++++++++++++++++++++++++++++- rust/kernel/lib.rs | 1 + 2 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs index 861746f2422d..5b9751d7ff1d 100644 --- a/rust/kernel/error.rs +++ b/rust/kernel/error.rs @@ -4,7 +4,14 @@ //! //! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h) -use alloc::collections::TryReserveError; +use alloc::{ + alloc::{AllocError, LayoutError}, + collections::TryReserveError, +}; + +use core::convert::From; +use core::num::TryFromIntError; +use core::str::Utf8Error; /// Contains the C-compatible error codes. pub mod code { @@ -71,12 +78,48 @@ impl Error { } } +impl From<AllocError> for Error { + fn from(_: AllocError) -> Error { + code::ENOMEM + } +} + +impl From<TryFromIntError> for Error { + fn from(_: TryFromIntError) -> Error { + code::EINVAL + } +} + +impl From<Utf8Error> for Error { + fn from(_: Utf8Error) -> Error { + code::EINVAL + } +} + impl From<TryReserveError> for Error { fn from(_: TryReserveError) -> Error { code::ENOMEM } } +impl From<LayoutError> for Error { + fn from(_: LayoutError) -> Error { + code::ENOMEM + } +} + +impl From<core::fmt::Error> for Error { + fn from(_: core::fmt::Error) -> Error { + code::EINVAL + } +} + +impl From<core::convert::Infallible> for Error { + fn from(e: core::convert::Infallible) -> Error { + match e {} + } +} + /// A [`Result`] with an [`Error`] error type. /// /// To be used as the return type for functions that may fail. diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index abd46261d385..ffc6626a6d29 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -12,6 +12,7 @@ //! do so first instead of bypassing this crate. #![no_std] +#![feature(allocator_api)] #![feature(core_ffi_c)] // Ensure conditional compilation based on the kernel configuration works; -- 2.38.1
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