def db_class(db_dir, name):
"""Returns a DB engine class."""
for db_class in util.subclasses(Storage):
if db_class.__name__.lower() == name.lower():
db_class.import_module()
return partial(db_class, db_dir)
raise RuntimeError(f'unrecognised DB engine "{name}"')
def lookup_xverbytes(verbytes):
"""Return a (is_xpub, coin_class) pair given xpub/xprv verbytes."""
# Order means BTC testnet will override NMC testnet
for coin in subclasses(Coin):
if verbytes == coin.XPUB_VERBYTES:
return True, coin
if verbytes == coin.XPRV_VERBYTES:
return False, coin
raise CoinError('version bytes unrecognised')
def lookup_coin_class(cls, name, net):
"""Return a coin class given name and network.
Raise an exception if unrecognised."""
req_attrs = ['TX_COUNT', 'TX_COUNT_HEIGHT', 'TX_PER_BLOCK']
for coin in subclasses(Coin):
if (coin.NAME.lower() == name.lower()
and coin.NET.lower() == net.lower()):
coin_req_attrs = req_attrs.copy()
missing = [
attr for attr in coin_req_attrs if not hasattr(coin, attr)
]
if missing:
raise CoinError(
f'coin {name} missing {missing} attributes')
return coin
raise CoinError(f'unknown coin {name} and network {net} combination')