nu-protocol 0.94.0

Nushell's internal protocols, including its abstract syntax tree
Documentation 
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use std::{fs::File, io, process::Stdio, sync::Arc};

/// Describes where to direct the stdout or stderr output stream of external command to.
#[derive(Debug, Clone)]
pub enum OutDest {
    /// Redirect the stdout and/or stderr of one command as the input for the next command in the pipeline.
    ///
    /// The output pipe will be available as the `stdout` of [`ChildProcess`](crate::process::ChildProcess).
    ///
    /// If stdout and stderr are both set to `Pipe`,
    /// then they will combined into the `stdout` of [`ChildProcess`](crate::process::ChildProcess).
    Pipe,
    /// Capture output to later be collected into a [`Value`](crate::Value), `Vec`, or used in some other way.
    ///
    /// The output stream(s) will be available in the `stdout` or `stderr` of [`ChildProcess`](crate::process::ChildProcess).
    ///
    /// This is similar to `Pipe` but will never combine stdout and stderr
    /// or place an external command's stderr into `stdout` of [`ChildProcess`](crate::process::ChildProcess).
    Capture,
    /// Ignore output.
    ///
    /// This will forward output to the null device for the platform.
    Null,
    /// Output to nushell's stdout or stderr.
    ///
    /// This causes external commands to inherit nushell's stdout or stderr.
    Inherit,
    /// Redirect output to a file.
    File(Arc<File>), // Arc<File>, since we sometimes need to clone `OutDest` into iterators, etc.
}

impl From<File> for OutDest {
    fn from(file: File) -> Self {
        Arc::new(file).into()
    }
}

impl From<Arc<File>> for OutDest {
    fn from(file: Arc<File>) -> Self {
        Self::File(file)
    }
}

impl TryFrom<&OutDest> for Stdio {
    type Error = io::Error;

    fn try_from(out_dest: &OutDest) -> Result<Self, Self::Error> {
        match out_dest {
            OutDest::Pipe | OutDest::Capture => Ok(Self::piped()),
            OutDest::Null => Ok(Self::null()),
            OutDest::Inherit => Ok(Self::inherit()),
            OutDest::File(file) => Ok(file.try_clone()?.into()),
        }
    }
}