Struct RawHasher 

pub struct RawHasher {
    digest: Sha256,
    size: u64,
}

A raw-block CID computed over bytes that arrive a chunk at a time.

Cid::of_raw needs the whole block in hand, which is the one thing a blob upload must never have: a personal data server that buffers a body before it hashes it is holding the whole file in memory to learn its name (a known defect in jacquard’s uploadBlob). This is the same hash, fed incrementally, so the bytes can go to their destination as they arrive and the name falls out at the end.

It counts as it hashes, because the size is the other half of a blob reference and a caller that tracked it separately could disagree with the bytes that were actually hashed.

use didbot_data::{Cid, RawHasher};
let mut hasher = RawHasher::new();
hasher.update(b"quernstone");
hasher.update(b"-farthingale");
let (cid, size) = hasher.finish();
assert_eq!(cid, Cid::of_raw(b"quernstone-farthingale"));
assert_eq!(size, 22);

Fields

digest: Sha256

size: u64

Implementations

impl RawHasher

pub fn new() -> Self

A hasher over nothing yet.

pub fn update(&mut self, chunk: &[u8])

Folds in the next chunk.

pub fn size(&self) -> u64

How many bytes have been folded in so far.

Readable mid-stream so a caller enforcing a size limit can stop at the byte that breaks it rather than after the body has been written out.

pub fn finish(self) -> (Cid, u64)

The CID of everything folded in, and how much that was.

Trait Implementations

impl Clone for RawHasher

fn clone(&self) -> RawHasher

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RawHasher

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

Formats the value using the given formatter.

impl Default for RawHasher

fn default() -> RawHasher

Returns the “default value” for a type.