rust/kernel: move from_kernel_result! macro to error.rs #266
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rust/kernel/error.rs
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| /// Transforms a `crate::error::Result<T>` to a kernel `C` integer result. |
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C is not code, i.e.:
| /// Transforms a `crate::error::Result<T>` to a kernel `C` integer result. | |
| /// Transforms a `crate::error::Result<T>` to a kernel C integer result. |
Does an intra-doc link work here?
| /// Transforms a `crate::error::Result<T>` to a kernel `C` integer result. | |
| /// Transforms a [`crate::error::Result<T>`] to a kernel C integer result. |
rust/kernel/error.rs
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| /// Transforms a `crate::error::Result<T>` to a kernel `C` integer result. | ||
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| /// This is useful when calling Rust functions that return `Result<T>` |
This macro is well-suited for use elsewhere in the Rust core. Move it out to a suitable place, error.rs. Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
This is required to pass the CI. Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
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| @@ -106,15 +106,20 @@ impl From<AllocError> for Error { | |||
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| // # Invariant: `-bindings::MAX_ERRNO` fits in an `i16`. | |||
| crate::static_assert!(bindings::MAX_ERRNO <= -(i16::MIN as i32) as u32); | |||
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I have the nagging feeling that this method is too contrived. Is there an idiomatic way to verify whether a value fits in a type? I tried Try or TryFrom but that doesn't work, because those types can't run inside a static_assert!.
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I have taken a look at this -- it is indeed a bit painful. After having tried several approaches, I am preparing a PR with a fun one.
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I am grabbing the popcorn !! :)
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See if you like #269 :)
It would allow you to do:
static_assert!((-(bindings::MAX_ERRNO as i128)) fits in i16);
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I like it a lot !! Will definitely rebase to that after it gets merged !! 💯
`from_kernel_result!` could panic if the return integer type (`T`) is unable to hold the negative `errno`. Since `errno`s range from `1` to `4095`, functions returning integer types unable to hold values in the [-4095, -1] range could potentially panic. This includes all unsigned integers, and signed integers with insufficient bits, such as `c_char`. Fix by making sure that the return integer type is always suitable to hold the negative `errno`. Use the Rust type system to verify this at build time. Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
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Corrected minor nit in commit message to restart CI (which failed due to inability to download packages). |
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Going to merge this now, and we can improve the static_assert in a follow-up PR. |
This macro is well-suited for use elsewhere in the Rust core.
Move it out to a suitable place, error.rs.
(I'd like to use this in #254)
v1 -> v2