def _find_oldest_unpruned_task_id(self, finished_task_id: TTaskID) -> TTaskID:
get_dependency_of_id = compose(
curry(do)(self._validate_has_task),
self._dependency_of,
attrgetter('task'),
self._tasks.get,
)
ancestors = iterate(get_dependency_of_id, finished_task_id)
return nth(self._max_depth, ancestors)
def get_ancestor_hash(self, block_number: int) -> Hash32:
ancestor_depth = self.block_number - block_number - 1
is_ancestor_depth_out_of_range = (
ancestor_depth >= MAX_PREV_HEADER_DEPTH or ancestor_depth < 0
or block_number < 0)
if is_ancestor_depth_out_of_range:
return Hash32(b'')
try:
return nth(ancestor_depth, self.execution_context.prev_hashes)
except StopIteration:
# Ancestor with specified depth not present
return Hash32(b'')
def get_ancestor_hash(self, block_number: int) -> Hash32:
"""
Return the hash for the ancestor block with number ``block_number``.
Return the empty bytestring ``b''`` if the block number is outside of the
range of available block numbers (typically the last 255 blocks).
"""
ancestor_depth = self.block_number - block_number - 1
is_ancestor_depth_out_of_range = (
ancestor_depth >= MAX_PREV_HEADER_DEPTH or ancestor_depth < 0
or block_number < 0)
if is_ancestor_depth_out_of_range:
return Hash32(b'')
try:
return nth(ancestor_depth, self.execution_context.prev_hashes)
except StopIteration:
# Ancestor with specified depth not present
return Hash32(b'')
def flatten(self) -> None:
if self.is_flattened:
return
checkpoint_after_root = nth(1, self._checkpoint_stack)
self.commit_checkpoint(checkpoint_after_root)
def flatten(self) -> None:
if self.is_flattened:
return
changeset_id_after_root = nth(1, self.journal_data.keys())
self.commit_changeset(changeset_id_after_root)
def test_cached_generator():
use_once = itertools.count()
repeated_use = CachedIterable(use_once)
for find_val in [1, 0, 10, 5]:
assert find_val == nth(find_val, repeated_use)
