/// <summary>
/// Applies an internally generated contract method call message to the current state.
/// </summary>
public StateTransitionResult Apply(IState state, InternalCallMessage message)
{
bool enoughBalance = EnsureSenderHasEnoughBalance(state, message.From, message.Amount);
if (!enoughBalance)
{
return(StateTransitionResult.Fail((Gas)0, StateTransitionErrorKind.InsufficientBalance)); // Trivial - just return and let the MethodCall gas account for it.
}
var gasMeter = new GasMeter(message.GasLimit);
gasMeter.Spend((Gas)GasPriceList.BaseCost);
byte[] contractCode = state.ContractState.GetCode(message.To);
if (contractCode == null || contractCode.Length == 0)
{
return(StateTransitionResult.Fail(gasMeter.GasConsumed, StateTransitionErrorKind.NoCode));
}
// For internal calls we need to add the value contained in the contract invocation transaction
// to the internal transfer list. This must occur before we apply the message to the state.
// For external calls we do not need to do this.
state.AddInternalTransfer(new TransferInfo(message.From, message.To, message.Amount));
StateTransitionResult result = ApplyCall(state, message, contractCode, gasMeter);
return(result);
}
///<inheritdoc />
public ITransferResult Call(
ISmartContractState smartContractState,
Address addressTo,
ulong amountToTransfer,
string methodName,
object[] parameters,
ulong gasLimit = 0)
{
Gas gasRemaining = this.gasMeter.GasAvailable;
// For a method call, send all the gas unless an amount was selected.Should only call trusted methods so re - entrance is less problematic.
ulong gasBudget = (gasLimit != 0) ? gasLimit : gasRemaining;
if (gasRemaining < gasBudget || gasRemaining < GasPriceList.BaseCost)
{
return(TransferResult.Failed());
}
var message = new InternalCallMessage(
addressTo.ToUint160(),
smartContractState.Message.ContractAddress.ToUint160(),
amountToTransfer,
(Gas)gasBudget,
new MethodCall(methodName, parameters)
);
// Create a snapshot of the current state
IState newState = this.state.Snapshot();
// Apply the message to the snapshot
StateTransitionResult result = this.stateProcessor.Apply(newState, message);
// Transition the current state to the new state
if (result.IsSuccess)
{
this.state.TransitionTo(newState);
}
this.gasMeter.Spend(result.GasConsumed);
return(result.IsSuccess
? TransferResult.Transferred(result.Success.ExecutionResult)
: TransferResult.Failed());
}