def _get_computation_error(state: StateAPI, transaction: SignedTransactionAPI) -> Optional[VMError]:
snapshot = state.snapshot()
try:
computation = state.apply_transaction(transaction)
if computation.is_error:
return computation.error
else:
return None
finally:
state.revert(snapshot)
def apply_create_message(
cls, state: StateAPI, message: MessageAPI,
transaction_context: TransactionContextAPI) -> ComputationAPI:
snapshot = state.snapshot()
# EIP161 nonce incrementation
state.increment_nonce(message.storage_address)
computation = cls.apply_message(state, message, transaction_context)
if computation.is_error:
state.revert(snapshot)
return computation
else:
contract_code = computation.output
if contract_code and len(contract_code) >= EIP170_CODE_SIZE_LIMIT:
computation.error = OutOfGas(
f"Contract code size exceeds EIP170 limit of {EIP170_CODE_SIZE_LIMIT}."
f" Got code of size: {len(contract_code)}")
state.revert(snapshot)
elif contract_code:
contract_code_gas_cost = len(
contract_code) * constants.GAS_CODEDEPOSIT
try:
computation.consume_gas(
contract_code_gas_cost,
reason="Write contract code for CREATE",
)
except OutOfGas as err:
# Different from Frontier: reverts state on gas failure while
# writing contract code.
computation.error = err
state.revert(snapshot)
else:
if cls.logger:
cls.logger.debug2(
"SETTING CODE: %s -> length: %s | hash: %s",
encode_hex(message.storage_address),
len(contract_code),
encode_hex(keccak(contract_code)))
state.set_code(message.storage_address, contract_code)
state.commit(snapshot)
else:
state.commit(snapshot)
return computation
def apply_create_message(
cls, state: StateAPI, message: MessageAPI,
transaction_context: TransactionContextAPI) -> ComputationAPI:
snapshot = state.snapshot()
# EIP161 nonce incrementation
state.increment_nonce(message.storage_address)
computation = cls.apply_message(state, message, transaction_context)
if computation.is_error:
state.revert(snapshot)
return computation
else:
contract_code = computation.output
if contract_code:
try:
cls.validate_contract_code(contract_code)
contract_code_gas_cost = len(
contract_code) * constants.GAS_CODEDEPOSIT
computation.consume_gas(
contract_code_gas_cost,
reason="Write contract code for CREATE",
)
except VMError as err:
# Different from Frontier: reverts state on gas failure while
# writing contract code.
computation.error = err
state.revert(snapshot)
cls.logger.debug2(f"VMError setting contract code: {err}")
else:
if cls.logger:
cls.logger.debug2(
"SETTING CODE: %s -> length: %s | hash: %s",
encode_hex(message.storage_address),
len(contract_code),
encode_hex(keccak(contract_code)))
state.set_code(message.storage_address, contract_code)
state.commit(snapshot)
else:
state.commit(snapshot)
return computation
def apply_message(
cls, state: StateAPI, message: MessageAPI,
transaction_context: TransactionContextAPI) -> ComputationAPI:
snapshot = state.snapshot()
if message.depth > STACK_DEPTH_LIMIT:
raise StackDepthLimit("Stack depth limit reached")
if message.should_transfer_value and message.value:
sender_balance = state.get_balance(message.sender)
if sender_balance < message.value:
raise InsufficientFunds(
f"Insufficient funds: {sender_balance} < {message.value}")
state.delta_balance(message.sender, -1 * message.value)
state.delta_balance(message.storage_address, message.value)
cls.logger.debug2(
"TRANSFERRED: %s from %s -> %s",
message.value,
encode_hex(message.sender),
encode_hex(message.storage_address),
)
state.touch_account(message.storage_address)
computation = cls.apply_computation(
state,
message,
transaction_context,
)
if computation.is_error:
state.revert(snapshot)
else:
state.commit(snapshot)
return computation