Re: [libgpiod][PATCH v2 5/5] bindings: rust: provide LineRequest::chip_name()

[Kent Gibson <warthog618@gmail.com>]

On Thu, Jul 20, 2023 at 04:47:47PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> Provide a wrapper around gpiod_line_request_get_chip_name() for Rust
> bindings and add a test-case.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
>  bindings/rust/libgpiod/src/line_request.rs   | 16 ++++++++++++++++
>  bindings/rust/libgpiod/tests/line_request.rs | 14 ++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/bindings/rust/libgpiod/src/line_request.rs b/bindings/rust/libgpiod/src/line_request.rs
> index 1140aa9..737c06f 100644
> --- a/bindings/rust/libgpiod/src/line_request.rs
> +++ b/bindings/rust/libgpiod/src/line_request.rs
> @@ -2,6 +2,7 @@
>  // SPDX-FileCopyrightText: 2022 Linaro Ltd.
>  // SPDX-FileCopyrightText: 2022 Viresh Kumar <viresh.kumar@linaro.org>
>  
> +use std::ffi::CStr;
>  use std::os::unix::prelude::AsRawFd;
>  use std::time::Duration;
>  
> @@ -25,6 +26,21 @@ impl Request {
>          Ok(Self { request })
>      }
>  
> +    /// Get the name of the chip this request was made on.
> +    pub fn chip_name(&self) -> Result<&str> {
> +        // SAFETY: The `gpiod_line_request` is guaranteed to be live as long
> +        // as `&self`
> +        let name = unsafe { gpiod::gpiod_line_request_get_chip_name(self.request) };
> +
> +        // SAFETY: The string is guaranteed to be valid, non-null and immutable
> +        // by the C API for the lifetime of the `gpiod_line_request`. The
> +        // `gpiod_line_request` is living as long as `&self`. The string is
> +        // returned read-only with a lifetime of `&self`.
> +        unsafe { CStr::from_ptr(name) }
> +            .to_str()
> +            .map_err(Error::StringNotUtf8)
> +    }
> +

I would drop the name temp var myself, but that is just a nit.

Other than that the series looks good to me.

Reviewed-by: Kent Gibson <warthog618@gmail.com>

Cheers,
Kent.