ethers-rs/ethers-contract/ethers-contract-abigen/src/rustfmt.rs

//! This module implements basic `rustfmt` code formatting.

use anyhow::{anyhow, Result};
use std::{
    io::Write,
    process::{Command, Stdio},
};

/// Format the raw input source string and return formatted output.
pub fn format<S>(source: S) -> Result<String>
where
    S: AsRef<str>,
{
    let mut rustfmt =
        Command::new("rustfmt").stdin(Stdio::piped()).stdout(Stdio::piped()).spawn()?;

    {
        let stdin = rustfmt
            .stdin
            .as_mut()
            .ok_or_else(|| anyhow!("stdin was not created for `rustfmt` child process"))?;
        stdin.write_all(source.as_ref().as_bytes())?;
    }

    let output = rustfmt.wait_with_output()?;
    if !output.status.success() {
        return Err(anyhow!(
            "`rustfmt` exited with code {}:\n{}",
            output.status,
            String::from_utf8_lossy(&output.stderr),
        ))
    }

    let stdout = String::from_utf8(output.stdout)?;
    Ok(stdout)
}