Re: [PATCH V7 4/8] libgpiod: Add rust examples

[Kent Gibson <warthog618@gmail.com>]

On Fri, Oct 14, 2022 at 04:17:21PM +0530, Viresh Kumar wrote:
> Add examples for the usage of the rust bindings, quite similar to the
> ones in cxx bindings.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  bindings/rust/libgpiod/examples/gpiodetect.rs | 30 ++++++
>  bindings/rust/libgpiod/examples/gpiofind.rs   | 35 +++++++
>  bindings/rust/libgpiod/examples/gpioget.rs    | 42 ++++++++
>  bindings/rust/libgpiod/examples/gpioinfo.rs   | 95 +++++++++++++++++++
>  bindings/rust/libgpiod/examples/gpiomon.rs    | 73 ++++++++++++++
>  bindings/rust/libgpiod/examples/gpioset.rs    | 60 ++++++++++++
>  bindings/rust/libgpiod/examples/gpiowatch.rs  | 54 +++++++++++
>  7 files changed, 389 insertions(+)
>  create mode 100644 bindings/rust/libgpiod/examples/gpiodetect.rs
>  create mode 100644 bindings/rust/libgpiod/examples/gpiofind.rs
>  create mode 100644 bindings/rust/libgpiod/examples/gpioget.rs
>  create mode 100644 bindings/rust/libgpiod/examples/gpioinfo.rs
>  create mode 100644 bindings/rust/libgpiod/examples/gpiomon.rs
>  create mode 100644 bindings/rust/libgpiod/examples/gpioset.rs
>  create mode 100644 bindings/rust/libgpiod/examples/gpiowatch.rs
> 

Add an example that exercises the event buffer, demonstrating that its is
not possible to read new events while the previous set are still in
use.

I added something along those lines, based on gpiomon, in my mods
branch mentioned in patch 3.

If multi-threading is supported, perhaps some examples demonstrating
that as well.  Even if there are tests that already cover it - major
features should have explicit examples, not require rooting around
through the test suite.

> diff --git a/bindings/rust/libgpiod/examples/gpiodetect.rs b/bindings/rust/libgpiod/examples/gpiodetect.rs
> new file mode 100644
> index 000000000000..f24ac72e2d48
> --- /dev/null
> +++ b/bindings/rust/libgpiod/examples/gpiodetect.rs
> @@ -0,0 +1,30 @@
> +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
> +//
> +// Copyright 2022 Linaro Ltd. All Rights Reserved.
> +//     Viresh Kumar <viresh.kumar@linaro.org>
> +//
> +// Simplified Rust implementation of gpiodetect tool.
> +
> +use std::env;
> +use std::path::Path;
> +
> +use libgpiod::{gpiochip_devices, Error, Result};
> +
> +fn main() -> Result<()> {
> +    let args: Vec<String> = env::args().collect();
> +    if args.len() > 1 {
> +        println!("Usage: {}", args[0]);
> +        return Err(Error::InvalidArguments);
> +    }
> +
> +    for chip in gpiochip_devices(&Path::new("/dev"))? {
> +        println!(
> +            "{} [{}] ({})",
> +            chip.name()?,
> +            chip.label()?,
> +            chip.num_lines(),
> +        );
> +    }
> +
> +    Ok(())
> +}
> diff --git a/bindings/rust/libgpiod/examples/gpiofind.rs b/bindings/rust/libgpiod/examples/gpiofind.rs
> new file mode 100644
> index 000000000000..07e886bc3896
> --- /dev/null
> +++ b/bindings/rust/libgpiod/examples/gpiofind.rs
> @@ -0,0 +1,35 @@
> +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
> +//
> +// Copyright 2022 Linaro Ltd. All Rights Reserved.
> +//     Viresh Kumar <viresh.kumar@linaro.org>
> +//
> +// Simplified Rust implementation of gpiofind tool.
> +
> +use std::env;
> +use std::path::Path;
> +
> +use libgpiod::{gpiochip_devices, Error, Result};
> +
> +fn main() -> Result<()> {
> +    let args: Vec<String> = env::args().collect();
> +    if args.len() != 2 {
> +        println!("Usage: {} <line-name>", args[0]);
> +        return Err(Error::InvalidArguments);
> +    }
> +
> +    for chip in gpiochip_devices(&Path::new("/dev"))? {
> +        let offset = chip.line_offset_from_name(&args[1]);
> +        if offset.is_ok() {
> +            println!(
> +                "Line {} found: Chip: {}, offset: {}",
> +                args[1],
> +                chip.name()?,
> +                offset?
> +            );
> +            return Ok(());
> +        }
> +    }
> +
> +    println!("Failed to find line: {}", args[1]);
> +    Ok(())
> +}
> diff --git a/bindings/rust/libgpiod/examples/gpioget.rs b/bindings/rust/libgpiod/examples/gpioget.rs
> new file mode 100644
> index 000000000000..f4c111987d96
> --- /dev/null
> +++ b/bindings/rust/libgpiod/examples/gpioget.rs
> @@ -0,0 +1,42 @@
> +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
> +//
> +// Copyright 2022 Linaro Ltd. All Rights Reserved.
> +//     Viresh Kumar <viresh.kumar@linaro.org>
> +//
> +// Simplified Rust implementation of gpioget tool.
> +
> +use std::env;
> +
> +use libgpiod::{chip::Chip, line, request, Direction, Error, Offset, Result, SettingVal};
> +
> +fn main() -> Result<()> {
> +    let args: Vec<String> = env::args().collect();
> +    if args.len() < 3 {
> +        println!("Usage: {} <chip> <line_offset0> ...", args[0]);
> +        return Err(Error::InvalidArguments);
> +    }
> +
> +    let mut lsettings = line::Settings::new()?;
> +    let lconfig = line::Config::new()?;
> +    let mut offsets = Vec::<Offset>::new();
> +
> +    for arg in &args[2..] {
> +        let offset = arg.parse::<Offset>().map_err(|_| Error::InvalidArguments)?;
> +        offsets.push(offset);
> +    }
> +
> +    lsettings.set_prop(&[SettingVal::Direction(Direction::Input)])?;

This is an example of where 

       lsettings.set_direction(Direction::Input)?;

would be simpler and clearer.

Cheers,
Kent.