use std::borrow::Cow; use smallvec::SmallVec; use crate::{immutable::object, BStr}; mod decode; ///pub mod iter; /// A git commit parsed using [`from_bytes()`][Commit::from_bytes()].////// A commit encapsulates information about a point in time at which the state of the repository is recorded, usually after a/// change which is documented in the commit `message`.#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Commit<'a> {    /// HEX hash of tree object we point to. Usually 40 bytes long.    ///    /// Use [`tree()`][Commit::tree()] to obtain a decoded version of it.    #[cfg_attr(feature = "serde1", serde(borrow))]    pub tree: &'a BStr,    /// HEX hash of each parent commit. Empty for first commit in repository.    pub parents: SmallVec<[&'a BStr; 2]>,    /// Who wrote this commit.    pub author: git_actor::immutable::Signature<'a>,    /// Who committed this commit.    ///    /// This may be different from the `author` in case the author couldn't write to the repository themselves and    /// is commonly encountered with contributed commits.    pub committer: git_actor::immutable::Signature<'a>,    /// The name of the message encoding, otherwise [UTF-8 should be assumed](https://github.com/git/git/blob/e67fbf927dfdf13d0b21dc6ea15dc3c7ef448ea0/commit.c#L1493:L1493).    pub encoding: Option<&'a BStr>,    /// The commit message documenting the change.    pub message: &'a BStr,    /// Extra header fields, in order of them being encountered, made accessible with the iterator returned by [`extra_headers()`][Commit::extra_headers()].    pub extra_headers: Vec<(&'a BStr, Cow<'a, BStr>)>,} impl<'a> Commit<'a> {    /// Deserialize a commit from the given `data` bytes while avoiding most allocations.    pub fn from_bytes(data: &'a [u8]) -> Result<Commit<'a>, object::decode::Error> {        decode::commit(data)            .map(|(_, t)| t)            .map_err(object::decode::Error::from)    }    /// Return the `tree` fields hash digest.    pub fn tree(&self) -> git_hash::ObjectId {        git_hash::ObjectId::from_hex(self.tree).expect("prior validation of tree hash during parsing")    }     /// Returns an iterator of parent object ids    pub fn parents(&self) -> impl Iterator<Item = git_hash::ObjectId> + '_ {        self.parents            .iter()            .map(|hex_hash| git_hash::ObjectId::from_hex(hex_hash).expect("prior validation of hashes during parsing"))    }     /// Returns a convenient iterator over all extra headers.    pub fn extra_headers(&self) -> crate::commit::ExtraHeaders<impl Iterator<Item = (&BStr, &BStr)>> {        crate::commit::ExtraHeaders::new(self.extra_headers.iter().map(|(k, v)| (*k, v.as_ref())))    }}