Struct Cas 

pub struct Cas { /* private fields */ }

Implementations

impl Cas

pub fn put_for( &mut self, bytes: &[u8], origin: &BlockOrigin, ) -> Result<B3Hash, StorageError>

Puts the bytes and records the origin they were put for. Ok means both the object and the record are durable; a second put with the same origin adds nothing.

Errors

StorageError::Io naming the path the store would not take.

pub fn origins(&self, hash: &B3Hash) -> Result<Vec<BlockOrigin>, StorageError>

Every origin recorded for a block, oldest first; empty for a block put with no origin and for a hash the store never saw.

Errors

StorageError::Io when a record exists and cannot be read.

impl Cas

pub fn open(dir: &Path) -> Result<Cas, StorageError>

Production entrance: std filesystem underneath.

pub fn put(&mut self, bytes: &[u8]) -> Result<B3Hash, StorageError>

Content-addressed put: hash, dedup by existence, tmp + sync + rename + dir sync. Ok means the named object is durable.

pub fn contains(&self, hash: &B3Hash) -> bool

Existence judgment; no failure surface.

pub fn get(&self, hash: &B3Hash) -> Result<Vec<u8>, StorageError>

Full read, re-verified against the address.

pub fn get_range( &self, hash: &B3Hash, range: &Range, ) -> Result<Vec<u8>, StorageError>

Range retrieval per the Locator grammar; out of bounds refuses.

The answer is read where it sits, so a fragment of a two hundred megabyte object costs the fragment. The price of that is stated in [ranges]: a range read cannot re-verify an address that covers the whole object, so it trusts what put verified, and a caller that needs the address proved calls Cas::get.

pub fn size(&self, hash: &B3Hash) -> Result<u64, StorageError>

The object’s length in bytes, read from the filesystem rather than from the object, so asking how long a two hundred megabyte version is costs nothing like two hundred megabytes. A window of a stored document version needs it to keep its request inside the object (crates/storage/spec/Cas.lean §8-36). Like a range read, it trusts what put verified.