use bstr::{BStr, BString, ByteSlice}; use crate::parse::Event;use crate::File; impl File<'_> {    /// Serialize this type into a `BString` for convenience.    ///    /// Note that `to_string()` can also be used, but might not be lossless.    #[must_use]    pub fn to_bstring(&self) -> BString {        let mut buf = Vec::new();        self.write_to(&mut buf).expect("io error impossible");        buf.into()    }     /// Stream ourselves to the given `out`, in order to reproduce this file mostly losslessly    /// as it was parsed.    pub fn write_to(&self, mut out: impl std::io::Write) -> std::io::Result<()> {        let nl = self.detect_newline_style();         {            for event in self.frontmatter_events.as_ref() {                event.write_to(&mut out)?;            }             if !ends_with_newline(self.frontmatter_events.as_ref(), nl, true) && self.sections.iter().next().is_some() {                out.write_all(nl)?;            }        }         let mut prev_section_ended_with_newline = true;        for section_id in &self.section_order {            if !prev_section_ended_with_newline {                out.write_all(nl)?;            }            let section = self.sections.get(section_id).expect("known section-id");            section.write_to(&mut out)?;             prev_section_ended_with_newline = ends_with_newline(section.body.0.as_ref(), nl, false);            if let Some(post_matter) = self.frontmatter_post_section.get(section_id) {                if !prev_section_ended_with_newline {                    out.write_all(nl)?;                }                for event in post_matter {                    event.write_to(&mut out)?;                }                prev_section_ended_with_newline = ends_with_newline(post_matter, nl, prev_section_ended_with_newline);            }        }         if !prev_section_ended_with_newline {            out.write_all(nl)?;        }         Ok(())    }} pub(crate) fn ends_with_newline(e: &[crate::parse::Event<'_>], nl: impl AsRef<[u8]>, default: bool) -> bool {    if e.is_empty() {        return default;    }    e.iter()        .rev()        .take_while(|e| e.to_bstr_lossy().iter().all(|b| b.is_ascii_whitespace()))        .find_map(|e| e.to_bstr_lossy().contains_str(nl.as_ref()).then(|| true))        .unwrap_or(false)} pub(crate) fn extract_newline<'a, 'b>(e: &'a Event<'b>) -> Option<&'a BStr> {    match e {        Event::Newline(b) => b.as_ref().into(),        _ => None,    }} pub(crate) fn platform_newline() -> &'static BStr {    if cfg!(windows) { "\r\n" } else { "\n" }.into()}