def get_prev_blocks(cls, last_block_hash: Hash32,
chaindb: BaseBeaconChainDB, max_search_depth: int,
min_slot_number: int) -> Iterable[BaseBeaconBlock]:
"""
Return the previous blocks.
Slot numbers are not guaranteed to be contiguous since it is possible for there
to be no block at a given slot. The search is bounded by two parameters.
- `max_search_depth` - The maximum number of slots below the slot of the block denoted by
`last_block_hash` that we should search.
- `min_slot_number` - The slot number for which we should NOT include any deeper if reached.
"""
if last_block_hash == GENESIS_PARENT_HASH:
return
block = chaindb.get_block_by_hash(last_block_hash)
for _ in range(max_search_depth):
yield block
try:
block = chaindb.get_block_by_hash(block.parent_hash)
except (IndexError, BlockNotFound):
break
# Only include the blocks that are greater than or equal to min_slot_number.
if block.slot_number < min_slot_number:
break
def attest_proposed_block(cls, post_crystallized_state: CrystallizedState,
post_active_state: ActiveState,
block_proposal: 'BlockProposal',
chaindb: BaseBeaconChainDB,
private_key: int) -> 'AttestationRecord':
"""
Return the initial attestation by the block proposer.
The proposer broadcasts their attestation with the proposed block.
"""
block_committees_info = get_block_committees_info(
block_proposal.block,
post_crystallized_state,
cls.config.CYCLE_LENGTH,
)
# Vote
attester_bitfield = set_voted(
get_empty_bitfield(block_committees_info.proposer_committee_size),
block_committees_info.proposer_index_in_committee,
)
# Get justified_slot and justified_block_hash
justified_slot = post_crystallized_state.last_justified_slot
justified_block_hash = chaindb.get_canonical_block_hash_by_slot(
justified_slot)
# Get signing message and sign it
parent_hashes = get_hashes_to_sign(
post_active_state.recent_block_hashes,
block_proposal.block,
cls.config.CYCLE_LENGTH,
)
message = create_signing_message(
block_proposal.block.slot_number,
parent_hashes,
block_proposal.shard_id,
block_proposal.shard_block_hash,
justified_slot,
)
sig = bls.sign(
message,
private_key,
)
return cls.get_attestation_record_class()(
slot=block_proposal.block.slot_number,
shard_id=block_proposal.shard_id,
oblique_parent_hashes=(),
shard_block_hash=block_proposal.shard_block_hash,
attester_bitfield=attester_bitfield,
justified_slot=justified_slot,
justified_block_hash=justified_block_hash,
aggregate_sig=sig,
)
def compute_per_block_transition(
cls,
crystallized_state: CrystallizedState,
active_state: ActiveState,
block: BaseBeaconBlock,
chaindb: BaseBeaconChainDB,
cycle_length: int,
is_validating_signatures: bool = True) -> ActiveState:
"""
Process ``block`` and return the new ActiveState.
TODO: It doesn't match the latest spec.
There will be more fields need to be updated in ActiveState.
"""
parent_block = chaindb.get_block_by_hash(block.parent_hash)
recent_block_hashes = get_new_recent_block_hashes(
active_state.recent_block_hashes, parent_block.slot_number,
block.slot_number, block.parent_hash)
if parent_block.parent_hash != GENESIS_PARENT_HASH:
validate_parent_block_proposer(
crystallized_state,
block,
parent_block,
cycle_length,
)
# TODO: to implement the RANDAO reveal validation.
cls.validate_randao_reveal()
for attestation in block.attestations:
validate_attestation(
block,
parent_block,
crystallized_state,
recent_block_hashes,
attestation,
chaindb,
cycle_length,
is_validating_signatures=is_validating_signatures,
)
return active_state.copy(
recent_block_hashes=recent_block_hashes,
pending_attestations=(active_state.pending_attestations +
block.attestations),
)