merkle

def call_key(identity: str, inputs: list[ContentHash]) -> CallKey:
    """The key of ``identity`` applied to arguments hashing to ``inputs``, in order."""
    hasher = blake3.blake3(derive_key_context=CALL_CONTEXT)
    name = identity.encode()
    hasher.update(_length(len(name)))
    hasher.update(name)
    hasher.update(_length(len(inputs)))
    for content in inputs:
        hasher.update(content.digest)
    return CallKey(ContentHash(hasher.digest()))

def hash_bytes(data: bytes, context: str = LEAF_CONTEXT) -> ContentHash:
    """The hash of ``data`` in ``context``'s domain."""
    return ContentHash(blake3.blake3(data, derive_key_context=context).digest())

def hash_tree(path: Path | str, cache: HashCache = NO_CACHE) -> ContentHash:
    """The merkle hash of the file or directory at ``path``.

    A file hashes its bytes; a directory hashes its entries in name order, each
    as its name, whether it is a directory, and its own hash. Hidden entries
    count like any other.

    Raises:
        FileNotFoundError: If ``path`` does not exist.
    """
    path = Path(path)
    stat = Stat.of(path)
    return _hash_directory(path, cache) if stat.is_dir else _hash_file(path, stat, cache)