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cardano streamed transactions
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class HashBuilderCollection: | |
def __init__(self, size: int) -> None: | |
self.size = size | |
self.remaining = size | |
self.hash_fn: HashContext | None = None | |
self.parent: "HashBuilderCollection" | None = None | |
self.have_nested_child = False | |
def start(self, hash_fn: HashContext) -> "HashBuilderCollection": | |
self.hash_fn = hash_fn | |
return self | |
def _insert_into_parent(self, parent: "HashBuilderCollection") -> None: | |
self.parent = parent | |
assert parent.hash_fn is not None | |
self.hash_fn = parent.hash_fn | |
parent.have_nested_child = True | |
self.hash_fn.update(self._header_bytes()) | |
def _do_enter_item(self) -> None: | |
assert self.hash_fn is not None | |
assert self.remaining > 0 | |
if self.have_nested_child: | |
raise RuntimeError # can't add item until child is done | |
self.remaing -= 1 | |
def _hash_item(self, item: Any) -> None: | |
assert self.hash_fn is not None | |
for chunk in cbor.encode_streamed(item): | |
self.hash_fn.update(chunk) | |
def _header_bytes(self) -> bytes: | |
raise NotImplementedError | |
def finish(self) -> None: | |
if self.remaining != 0: | |
raise RuntimeError # not all items were added | |
if self.parent is not None: | |
self.parent.have_nested_child = False | |
self.hash_fn = None | |
self.parent = None | |
def __enter__(self) -> "HashBuilderCollection": | |
assert self.hash_fn is not None | |
return self | |
def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> None: | |
self.finish() | |
class LazyList(HashBuilderCollection, Generic[T]): | |
def append(self, item: T) -> T: | |
self._do_enter_item() | |
if isinstance(item, HashBuilderCollection): | |
item._insert_into_parent(self) | |
else: | |
self._hash_item(item) | |
return item | |
def _header_bytes(self) -> bytes: | |
return cbor.create_array_header(self.size) | |
class LazyDict(HashBuilderCollection, Generic[K, V]): | |
def add(self, key: K, value: V) -> V: | |
self._do_enter_item() | |
# enter key, this must not nest | |
assert not isinstance(key, HashBuilderCollection) | |
self._hash_item(key) | |
# enter value, this can nest | |
if isinstance(value, HashBuilderCollection): | |
value._insert_into_parent(self) | |
else: | |
self._hash_item(value) | |
return value | |
def _header_bytes(self) -> bytes: | |
return cbor.create_map_header(self.size) |
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