Enum LoadedBlob 

pub enum LoadedBlob {
    Inline(Vec<u8>),
    Chunked(ChunkedBlob),
}

A blob’s top-level object, read from the store exactly once and held so a caller needing several views of the same blob — byte length, bounded prefix, full content — pays a single top-level read_object instead of one per view. diff --stat is the motivating caller: its text-vs-binary sniff needs a prefix, then either the length (binary row) or the full content (text row), and taking each view through a separate store-level read re-read (and re-hash-verified) the same object two times per changed file, a per-entry cost that dominates a many-small-files diffstat (#624).

Chunk objects are still read on demand: Self::len reads none, Self::prefix reads only leading chunks, Self::into_content reads them all.

One read stays undeduped by design: Self::prefix on a chunked blob reads the leading chunk(s) to sniff, and Self::into_content reads every chunk (including that same leading one) to reassemble — a caller doing both, as diff --stat does, reads the first chunk twice. Caching it would need either interior mutability or a consuming-prefix API, to save an O(1) read on an O(n-chunks) path; not worth it (#624).

Variants

Inline(Vec<u8>)

An inline Blob: its full content, already in hand.

Chunked(ChunkedBlob)

A ChunkedBlob manifest: content lives in chunk objects, read only when a view needs them.

Implementations

impl LoadedBlob

pub fn load<S: ObjectSource + ?Sized>( store: &S, hash: &Hash, ) -> WorktreeResult<Self>

Read the top-level object addressed by hash — one store read.

Errors

• WorktreeError::Store if hash is missing.
• WorktreeError::Io if hash resolves to an object that is neither a Blob nor a ChunkedBlob.

pub fn len(&self) -> u64

Content byte length from what is already in hand — an inline blob’s data length, a chunked blob’s manifest total_size — no chunk reads. total_size is trustworthy without re-verifying against the chunks: every reassembly path enforces it via ChunkedBlob::check_reassembled_size, so a manifest with a wrong total_size cannot have been durably written (#550).

pub fn is_empty(&self) -> bool

Whether the content is zero bytes long.

pub fn prefix<S: ObjectSource + ?Sized>( &self, store: &S, max_len: usize, ) -> WorktreeResult<Cow<'_, [u8]>>

Up to max_len leading content bytes. Inline data is borrowed (no copy, no reads); a chunked blob reads only as many leading chunks as it takes to cover max_len, then stops — one chunk in practice, since every chunk but possibly the last is at least crate::chunker::MIN_SIZE bytes, well above the sniff windows callers use (e.g. crate::ops::diff::BINARY_SNIFF_LEN).

Errors

• WorktreeError::Store if a needed chunk is missing.
• WorktreeError::Io if a needed chunk is not a Blob.

pub fn into_content<S: ObjectSource + ?Sized>( self, store: &S, ) -> WorktreeResult<Vec<u8>>

The full content: inline data as-is (no further reads), a chunked blob reassembled by reading every chunk, with the result length enforced against the manifest’s total_size (SPEC-OBJECTS §7).

Errors

• WorktreeError::Store if a chunk is missing.
• WorktreeError::Io if a chunk is not a Blob.
• WorktreeError::Object if the concatenated chunks do not total the manifest’s total_size.

pub fn empty() -> Self

The empty blob: what a diff side with no object (an add’s old side, a delete’s new side) loads as. Zero length, empty prefix, empty content — no store reads.

Trait Implementations

impl Debug for LoadedBlob

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.