Repository: nushell/nushell
File: crates/nu-command/src/random/binary.rs (Rust)

Code before:
    let mut remaining_bytes = length;
    PipelineData::ByteStream(
        ByteStream::from_fn(span, signals.clone(), stream_type, move |out| {
            if remaining_bytes == 0 || signals.interrupted() {
                return Ok(false);
            }

            let bytes_to_write = std::cmp::min(remaining_bytes, OUTPUT_CHUNK_SIZE);

            let rng = thread_rng();
            let byte_iter: Box<dyn Iterator<Item = u8>> = match distribution {
                RandomDistribution::Binary => Box::new(rng.sample_iter(Standard)),
                RandomDistribution::Alphanumeric => Box::new(rng.sample_iter(Alphanumeric)),
            };
            out.extend(byte_iter.take(bytes_to_write));

            remaining_bytes -= bytes_to_write;

            Ok(true)
        })
        .with_known_size(Some(length as u64)),
        None,
    )
    .with_span(span)
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_examples() {
        use crate::test_examples;

        test_examples(RandomBinary {})
    }
}


Review comment (refactor):
I would move this out of `random::binary`. It is shared behavior between `random::binary` and `random::chars`, so I would place it either in new module and make it `pub(super)` or place it directly inside `random` and don't make it `pub`.

Code after:
use super::byte_stream::{random_byte_stream, RandomDistribution};
use nu_engine::command_prelude::*;

#[derive(Clone)]
pub struct RandomBinary;

impl Command for RandomBinary {
    fn name(&self) -> &str {
        "random binary"
    }

    fn signature(&self) -> Signature {
        Signature::build("random binary")
            .input_output_types(vec![(Type::Nothing, Type::Binary)])
            .allow_variants_without_examples(true)
            .required(
                "length",
                SyntaxShape::OneOf(vec![SyntaxShape::Int, SyntaxShape::Filesize]),
                "Length of the output binary.",
            )
            .category(Category::Random)
    }

    fn description(&self) -> &str {
        "Generate random bytes."
    }

    fn search_terms(&self) -> Vec<&str> {
        vec!["generate", "bytes"]
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        _input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        let length_val = call.req(engine_state, stack, 0)?;
        let length = match length_val {
            Value::Int { val, .. } => usize::try_from(val).map_err(|_| ShellError::InvalidValue {
                valid: "a non-negative int or filesize".into(),
                actual: val.to_string(),
                span: length_val.span(),
            }),
            Value::Filesize { val, .. } => {
                usize::try_from(val).map_err(|_| ShellError::InvalidValue {
                    valid: "a non-negative int or filesize".into(),
                    actual: engine_state.get_config().filesize.format(val).to_string(),
                    span: length_val.span(),
                })
            }
            val => Err(ShellError::RuntimeTypeMismatch {
                expected: Type::custom("int or filesize"),
                actual: val.get_type(),
                span: val.span(),
            }),
        }?;

        Ok(random_byte_stream(
            RandomDistribution::Binary,
            length,
            call.head,
            engine_state.signals().clone(),
        ))
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Generate 16 random bytes",
                example: "random binary 16",
                result: None,
            },
            Example {
                description: "Generate 1 random kilobyte",
                example: "random binary 1kb",
                result: None,
            },
        ]
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_examples() {
        use crate::test_examples;

        test_examples(RandomBinary {})
    }
}