nushell/src/commands/shells.rs

use crate::commands::WholeStreamCommand;
use crate::prelude::*;
use nu_errors::ShellError;
use nu_protocol::{Signature, TaggedDictBuilder};
use std::sync::atomic::Ordering;

pub struct Shells;

impl WholeStreamCommand for Shells {
    fn name(&self) -> &str {
        "shells"
    }

    fn signature(&self) -> Signature {
        Signature::build("shells")
    }

    fn usage(&self) -> &str {
        "Display the list of current shells."
    }

    fn run(
        &self,
        args: CommandArgs,
        registry: &CommandRegistry,
    ) -> Result<OutputStream, ShellError> {
        shells(args, registry)
    }
}

fn shells(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
    let mut shells_out = VecDeque::new();
    let tag = args.call_info.name_tag;

    for (index, shell) in args
        .shell_manager
        .shells
        .lock()
        .map_err(|_| {
            ShellError::labeled_error("Could not list shells", "could not list shells", &tag)
        })?
        .iter()
        .enumerate()
    {
        let mut dict = TaggedDictBuilder::new(&tag);

        if index == (*args.shell_manager.current_shell).load(Ordering::SeqCst) {
            dict.insert_untagged(" ", "X".to_string());
        } else {
            dict.insert_untagged(" ", " ".to_string());
        }
        dict.insert_untagged("name", shell.name());
        dict.insert_untagged("path", shell.path());

        shells_out.push_back(dict.into_value());
    }

    Ok(shells_out.to_output_stream())
}