Struct ev3dev_lang_rust::Attribute

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pub struct Attribute { /* private fields */ }

Expand description

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

Implementations

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impl Attribute

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

Create a new Attribute instance for the given path.

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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}.

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pub fn from_path_with_discriminator(
 root_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 $d in root_path and checks if the content of root_path/$d/discriminator_path equals discriminator_value. When a match is found it returns an Attribute for file root_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>()?);

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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.

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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.

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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.

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