//! Contains a borrowed Object bound to a buffer holding its decompressed data. use crate::{BlobRef, CommitRef, CommitRefIter, Data, Kind, ObjectRef, TagRef, TagRefIter, TreeRef, TreeRefIter}; impl<'a> Data<'a> {    /// Constructs a new data object from `data`, `kind` and `object_hash`.    pub fn new(data: &'a [u8], kind: Kind, hash_kind: gix_hash::Kind) -> Data<'a> {        Data {            kind,            object_hash: hash_kind,            data,        }    }    /// Decodes the data in the backing slice into a [`ObjectRef`], allowing to access all of its data    /// conveniently. The cost of parsing an object is negligible.    ///    /// **Note** that [mutable, decoded objects][crate::Object] can be created from [`Data`]    /// using [`crate::ObjectRef::into_owned()`].    pub fn decode(&self) -> Result<ObjectRef<'a>, crate::decode::Error> {        Ok(match self.kind {            Kind::Tree => ObjectRef::Tree(TreeRef::from_bytes(self.data, self.object_hash)?),            Kind::Blob => ObjectRef::Blob(BlobRef { data: self.data }),            Kind::Commit => ObjectRef::Commit(CommitRef::from_bytes(self.data, self.object_hash)?),            Kind::Tag => ObjectRef::Tag(TagRef::from_bytes(self.data, self.object_hash)?),        })    }     /// Returns this object as tree iterator to parse entries one at a time to avoid allocations, or    /// `None` if this is not a tree object.    pub fn try_into_tree_iter(self) -> Option<TreeRefIter<'a>> {        match self.kind {            Kind::Tree => Some(TreeRefIter::from_bytes(self.data, self.object_hash)),            _ => None,        }    }     /// Returns this object as commit iterator to parse tokens one at a time to avoid allocations, or    /// `None` if this is not a commit object.    pub fn try_into_commit_iter(self) -> Option<CommitRefIter<'a>> {        match self.kind {            Kind::Commit => Some(CommitRefIter::from_bytes(self.data, self.object_hash)),            _ => None,        }    }     /// Returns this object as tag iterator to parse tokens one at a time to avoid allocations, or    /// `None` if this is not a tag object.    pub fn try_into_tag_iter(self) -> Option<TagRefIter<'a>> {        match self.kind {            Kind::Tag => Some(TagRefIter::from_bytes(self.data, self.object_hash)),            _ => None,        }    }} /// Types supporting object hash verificationpub mod verify {    /// Returned by [`crate::Data::verify_checksum()`]    #[derive(Debug, thiserror::Error)]    #[expect(missing_docs)]    pub enum Error {        #[error("Failed to hash object")]        Hasher(#[from] gix_hash::hasher::Error),        #[error(transparent)]        Verify(#[from] gix_hash::verify::Error),    }     impl crate::Data<'_> {        /// Compute the checksum of `self` and compare it with the `expected` hash.        /// If the hashes do not match, an [`Error`] is returned, containing the actual        /// hash of `self`.        pub fn verify_checksum(&self, expected: &gix_hash::oid) -> Result<gix_hash::ObjectId, Error> {            let actual = crate::compute_hash(expected.kind(), self.kind, self.data)?;            actual.verify(expected)?;            Ok(actual)        }    }} #[cfg(test)]mod tests {    use super::*;     #[test]    fn size_of_object() {        #[cfg(target_pointer_width = "64")]        assert_eq!(std::mem::size_of::<Data<'_>>(), 24, "this shouldn't change unnoticed");        #[cfg(target_pointer_width = "32")]        assert_eq!(std::mem::size_of::<Data<'_>>(), 12, "this shouldn't change unnoticed");    }}