Struct Attribute

pub struct Attribute { /* private fields */ }

A wrapper to a attribute file in the /sys/class/ directory.

Implementations

impl Attribute

pub fn from_path(path: &Path) -> Ev3Result<Attribute>

Create a new Attribute instance for the given path.

pub fn from_sys_class( class_name: &str, name: &str, attribute_name: &str, ) -> Ev3Result<Attribute>

Create a new Attribute instance that wrap’s the file /sys/class/{class_name}/{name}{attribute_name}.

pub fn from_path_with_discriminator( driver_path: &str, attribute_path: &str, discriminator_path: &str, discriminator_value: &str, ) -> Ev3Result<Attribute>

Create a new Attribute instance by a discriminator attribute. This can be used to manually access driver files or advances features like raw encoder values. To find the correct file, this function iterates over all directories $d in driver_path and checks if the content of driver_path/$d/discriminator_path equals discriminator_value. When a match is found it returns an Attribute for file driver_path/$d/attribute_path.

Example

use ev3dev_lang_rust::Attribute;

// Get value0 of first connected color sensor.
let color_sensor_value = Attribute::from_path_with_discriminator(
    "/sys/class/lego-sensor",
    "value0",
    "driver_name",
    "lego-ev3-color"
)?;
println!("value0 of color sensor: {}", color_sensor_value.get::<i32>()?);

// Get raw rotation count of motor in port `A`.
// See https://github.com/ev3dev/ev3dev/wiki/Internals:-ev3dev-stretch for more information.
let rotation_count = Attribute::from_path_with_discriminator(
    "/sys/bus/iio/devices",
    "in_count0_raw",
    "name",
    "ev3-tacho"
)?;
println!("Raw rotation count: {}", rotation_count.get::<i32>()?);

Examples found in repository

examples/custom-attributes.rs (lines 8-13)

fn main() -> Ev3Result<()> {
    // Get value0 of first connected color sensor.
    let color_sensor_value = Attribute::from_path_with_discriminator(
        "/sys/class/lego-sensor",
        "value0",
        "driver_name",
        "lego-ev3-color",
    )?;

    // Get raw rotation count of motor in port `A`.
    // See https://github.com/ev3dev/ev3dev/wiki/Internals:-ev3dev-stretch for more infomation.
    let rotation_count = Attribute::from_path_with_discriminator(
        "/sys/bus/iio/devices",
        "in_count0_raw",
        "name",
        "ev3-tacho",
    )?;

    loop {
        println!(
            "value0 of color sensor: {}",
            color_sensor_value.get::<i32>()?
        );
        println!("Raw rotation count: {}", rotation_count.get::<i32>()?);

        std::thread::sleep(std::time::Duration::from_secs(1));
    }
}

pub fn get<T>(&self) -> Ev3Result<T>

where T: FromStr, <T as FromStr>::Err: Error,

Returns the current value of the wrapped file. The value is parsed to the type T. Returns a Ev3Result::InternalError if the current value is not parsable to type T.

Examples found in repository

examples/custom-attributes.rs (line 27)

fn main() -> Ev3Result<()> {
    // Get value0 of first connected color sensor.
    let color_sensor_value = Attribute::from_path_with_discriminator(
        "/sys/class/lego-sensor",
        "value0",
        "driver_name",
        "lego-ev3-color",
    )?;

    // Get raw rotation count of motor in port `A`.
    // See https://github.com/ev3dev/ev3dev/wiki/Internals:-ev3dev-stretch for more infomation.
    let rotation_count = Attribute::from_path_with_discriminator(
        "/sys/bus/iio/devices",
        "in_count0_raw",
        "name",
        "ev3-tacho",
    )?;

    loop {
        println!(
            "value0 of color sensor: {}",
            color_sensor_value.get::<i32>()?
        );
        println!("Raw rotation count: {}", rotation_count.get::<i32>()?);

        std::thread::sleep(std::time::Duration::from_secs(1));
    }
}

pub fn set<T>(&self, value: T) -> Ev3Result<()>

where T: ToString,

Sets the value of the wrapped file. The value is parsed from the type T. Returns a Ev3Result::InternalError if the file is not writable.

pub fn set_str_slice(&self, value: &str) -> Ev3Result<()>

Sets the value of the wrapped file. This function skips the string parsing of the self.set<T>() function. Returns a Ev3Result::InternalError if the file is not writable.

pub fn get_vec(&self) -> Ev3Result<Vec<String>>

Returns a string vector representation of the wrapped file. The file value is splitted at whitespace’s.

pub fn get_raw_fd(&self) -> RawFd

Returns a C pointer to the wrapped file.

pub fn get_file_path(&self) -> PathBuf

Returns the path to the wrapped file.

Trait Implementations

impl Clone for Attribute

fn clone(&self) -> Attribute

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Attribute

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.