def _set_as_canonical_chain_head(
cls,
db: BaseDB,
block_hash: Hash32,
) -> Tuple[Tuple[BlockHeader, ...], Tuple[BlockHeader, ...]]:
try:
header = cls._get_block_header_by_hash(db, block_hash)
except HeaderNotFound:
raise ValueError(
"Cannot use unknown block hash as canonical head: {}".format(
header.hash))
new_canonical_headers = tuple(
reversed(cls._find_new_ancestors(db, header)))
old_canonical_headers = []
# remove transaction lookups for blocks that are no longer canonical
for h in new_canonical_headers:
try:
old_hash = cls._get_canonical_block_hash(db, h.block_number)
except HeaderNotFound:
# no old block, and no more possible
break
else:
old_header = cls._get_block_header_by_hash(db, old_hash)
old_canonical_headers.append(old_header)
for transaction_hash in cls._get_block_transaction_hashes(
db, old_header):
cls._remove_transaction_from_canonical_chain(
db, transaction_hash)
for h in new_canonical_headers:
cls._add_block_number_to_hash_lookup(db, h)
db.set(SchemaV1.make_canonical_head_hash_lookup_key(), header.hash)
return new_canonical_headers, tuple(old_canonical_headers)
def _get_canonical_head(cls, db: BaseDB) -> BlockHeader:
try:
canonical_head_hash = db[SchemaV1.make_canonical_head_hash_lookup_key()]
except KeyError:
raise CanonicalHeadNotFound("No canonical head set for this chain")
return cls._get_block_header_by_hash(db, canonical_head_hash)
def _get_canonical_head_hash(cls, db: DatabaseAPI) -> Hash32:
try:
return Hash32(db[SchemaV1.make_canonical_head_hash_lookup_key()])
except KeyError:
raise CanonicalHeadNotFound("No canonical head set for this chain")
