use anyhow::bail;use gix::{    bstr::BString,    dir::{        EntryRef,        walk::{self, EmissionMode},    },}; use crate::OutputFormat; #[derive(Copy, Clone)]pub enum Untracked {    Collapsed,    Matching,} pub struct Options {    pub output_format: OutputFormat,    pub statistics: bool,    pub untracked: Untracked,} pub fn walk(    repo: gix::Repository,    patterns: Vec<BString>,    mut out: impl std::io::Write,    mut err: impl std::io::Write,    Options {        output_format,        statistics,        untracked,    }: Options,) -> anyhow::Result<()> {    if output_format != OutputFormat::Human {        bail!("Only human format is supported right now");    }    let index = repo.index_or_empty()?;    let options = repo.dirwalk_options()?.emit_untracked(match untracked {        Untracked::Collapsed => EmissionMode::CollapseDirectory,        Untracked::Matching => EmissionMode::Matching,    });     let start = std::time::Instant::now();    let mut delegate = Count::default();    let outcome = repo.dirwalk(        &index,        patterns,        &gix::interrupt::IS_INTERRUPTED,        options,        &mut delegate,    )?;     if statistics {        writeln!(            err,            "dirwalk done {} entries in {:.2?}",            delegate.entries,            start.elapsed()        )?;        writeln!(err, "{:?}", outcome.dirwalk)?;    } else {        writeln!(out, "{}", delegate.entries)?;    }    Ok(())} #[derive(Default)]struct Count {    entries: u64,} impl walk::Delegate for Count {    fn emit(        &mut self,        _entry: EntryRef<'_>,        _collapsed_directory_status: Option<gix::dir::entry::Status>,    ) -> walk::Action {        self.entries += 1;        std::ops::ControlFlow::Continue(())    }}