use std::{cmp::Ordering, io}; use bstr::{BString, ByteSlice};use quick_error::quick_error; use crate::{mutable::SPACE, tree::EntryMode}; quick_error! {    /// The Error used in [`Tree::write_to()`].    #[derive(Debug)]    #[allow(missing_docs)]    pub enum Error {        NewlineInFilename(name: BString) {            display("Newlines are invalid in file paths: {:?}", name)        }    }} impl From<Error> for io::Error {    fn from(err: Error) -> Self {        io::Error::new(io::ErrorKind::Other, err)    }} /// A mutable Tree, containing other trees, blobs or commits.#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Tree {    /// The directories and files contained in this tree. They must be and remain sorted by [`filename`][Entry::filename].    pub entries: Vec<Entry>,} /// An entry in a [`Tree`], similar to an entry in a directory.#[derive(PartialEq, Eq, Debug, Hash, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Entry {    /// The kind of object to which `oid` is pointing to.    pub mode: EntryMode,    /// The name of the file in the parent tree.    pub filename: BString,    /// The id of the object representing the entry.    pub oid: git_hash::ObjectId,} impl PartialOrd for Entry {    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {        Some(self.cmp(other))    }} impl Ord for Entry {    /// Entries compare by the common portion of the filename. This is critical for proper functioning of algorithms working on trees.    fn cmp(&self, other: &Self) -> Ordering {        let len = self.filename.len().min(other.filename.len());        self.filename[..len].cmp(&other.filename[..len])    }} /// Serializationimpl EntryMode {    /// Return the representation as used in the git internal format.    pub fn as_bytes(&self) -> &'static [u8] {        use EntryMode::*;        match self {            Tree => b"40000",            Blob => b"100644",            BlobExecutable => b"100755",            Link => b"120000",            Commit => b"160000",        }    }} /// Serializationimpl Tree {    /// Serialize this tree to `out` in the git internal format.    pub fn write_to(&self, mut out: impl io::Write) -> io::Result<()> {        debug_assert_eq!(            &{                let mut entries_sorted = self.entries.clone();                entries_sorted.sort();                entries_sorted            },            &self.entries,            "entries for serialization must be sorted by filename"        );        for Entry { mode, filename, oid } in &self.entries {            out.write_all(mode.as_bytes())?;            out.write_all(SPACE)?;             if filename.find_byte(b'\n').is_some() {                return Err(Error::NewlineInFilename(filename.to_owned()).into());            }            out.write_all(filename)?;            out.write_all(&[b'\0'])?;             out.write_all(oid.as_bytes())?;        }        Ok(())    }}