Struct Entry 

pub struct Entry { /* private fields */ }

One archive entry: a tiling of chunks, each placed at its own fdata_offset.

Why this is a struct and not a trait

It was a trait — EntryReader, with two implementations that differed in how they COMBINE: chunks concatenate, deltas apply. That difference is what forced two of them, and it put the seam on the read side.

The seam belongs on the write side instead. A splitter decides how to cut a file into stored units (see Splitter); a unit it may emit is a reference to another entry. Reconstruction then stays exactly one loop — the loop below, which is the pre-trait extract_inner code — and the recursion lives in [ChunkSource].

What that buys, and it is the reason for the swap: a single file can be part chunk and part delta. A large file with one changed region stores the changed region as a delta and the rest as ordinary chunks. EntryReader was all-or-nothing per entry and could not say that.

What it leaves alone: the read path, which is the half that is measured and proven. chunked_reconstruction_is_byte_identical_to_the_pre_trait_implementation pins that with one blake3 over a deterministic corpus, and that constant has now survived both the trait’s arrival and its removal.

Implementations

impl Entry

pub fn uncompressed_size(&self) -> u64

Size of the reconstructed entry in bytes, as the index declares it. Untrusted: never size an allocation from it.

pub fn reconstruct( &self, path: &str, ctx: &ReconstructCtx<'_>, verify: bool, ) -> Result<Vec<u8>>

Reconstruct the entry’s bytes. path is carried for error messages only. With verify, each chunk’s bytes are blake3-checked against what the index recorded for it (Design law 3).