139 lines · 4.3 KB · Rust
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use std::convert::TryFrom; use crate::{    immutable::{object::decode, parse::SPACE},    tree,};use bstr::{BStr, ByteSlice};use nom::{    bytes::complete::{tag, take, take_while1, take_while_m_n},    character::is_digit,    combinator::all_consuming,    multi::many0,    sequence::terminated,    IResult,}; /// A directory snapshot containing files (blobs), directories (trees) and submodules (commits).#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Tree<'a> {    /// The directories and files contained in this tree.    #[cfg_attr(feature = "serde1", serde(borrow))]    pub entries: Vec<Entry<'a>>,} /// A directory snapshot containing files (blobs), directories (trees) and submodules (commits), lazily evaluated.#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct TreeIter<'a> {    /// The directories and files contained in this tree.    #[cfg_attr(feature = "serde1", serde(borrow))]    data: &'a [u8],} impl<'a> TreeIter<'a> {    /// Instantiate an iterator from the given tree data.    pub fn from_bytes(data: &'a [u8]) -> TreeIter<'a> {        TreeIter { data }    }} /// An element of a [`Tree`][Tree::entries].#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Entry<'a> {    /// The kind of object to which `oid` is pointing.    pub mode: tree::EntryMode,    /// The name of the file in the parent tree.    pub filename: &'a BStr,    /// The id of the object representing the entry.    #[cfg_attr(feature = "serde1", serde(borrow))]    pub oid: &'a git_hash::oid,} impl<'a> Tree<'a> {    /// Deserialize a Tree from `data`.    pub fn from_bytes(data: &'a [u8]) -> Result<Tree<'a>, decode::Error> {        parse(data).map(|(_, t)| t).map_err(decode::Error::from)    }     /// Create an instance of the empty tree.    ///    /// It's particularly useful as static part of a program.    pub const fn empty() -> Tree<'static> {        Tree { entries: Vec::new() }    }} impl<'a> TreeIter<'a> {    /// Consume self and return all parsed entries.    pub fn entries(self) -> Result<Vec<Entry<'a>>, decode::Error> {        self.collect()    }} impl<'a> Default for TreeIter<'a> {    fn default() -> Self {        TreeIter { data: &[] }    }} impl<'a> Iterator for TreeIter<'a> {    type Item = Result<Entry<'a>, decode::Error>;     fn next(&mut self) -> Option<Self::Item> {        if self.data.is_empty() {            return None;        }        match parse_entry(self.data) {            Ok((data_left, entry)) => {                self.data = data_left;                Some(Ok(entry))            }            Err(err) => {                self.data = &[];                Some(Err(err.into()))            }        }    }} impl TryFrom<&[u8]> for tree::EntryMode {    type Error = decode::Error;     fn try_from(mode: &[u8]) -> Result<Self, Self::Error> {        Ok(match mode {            b"40000" => tree::EntryMode::Tree,            b"100644" => tree::EntryMode::Blob,            b"100664" => tree::EntryMode::Blob, // rare and found in the linux kernel            b"100640" => tree::EntryMode::Blob, // rare and found in the Rust repo            b"100755" => tree::EntryMode::BlobExecutable,            b"120000" => tree::EntryMode::Link,            b"160000" => tree::EntryMode::Commit,            _ => return Err(decode::Error::NomDetail(mode.into(), "unknown tree mode")),        })    }} const NULL: &[u8] = b"\0";fn parse_entry(i: &[u8]) -> IResult<&[u8], Entry<'_>, decode::Error> {    let (i, mode) = terminated(take_while_m_n(5, 6, is_digit), tag(SPACE))(i)?;    let mode = tree::EntryMode::try_from(mode).map_err(nom::Err::Error)?;    let (i, filename) = terminated(take_while1(|b| b != NULL[0]), tag(NULL))(i)?;    let (i, oid) = take(20u8)(i)?;     Ok((        i,        Entry {            mode,            filename: filename.as_bstr(),            oid: git_hash::oid::try_from(oid).expect("we counted exactly 20 bytes"),        },    ))} fn parse(i: &[u8]) -> IResult<&[u8], Tree<'_>, decode::Error> {    let (i, entries) = all_consuming(many0(parse_entry))(i)?;    Ok((i, Tree { entries }))}