public TransactionBuildingContext CreateMemento()
{
var memento = new TransactionBuildingContext(Builder);
memento.RestoreMemento(this);
return(memento);
}
private IEnumerable <ICoin> BuildTransaction(
TransactionBuildingContext ctx,
BuilderGroup group,
IEnumerable <Builder> builders,
IEnumerable <ICoin> coins)
{
var originalCtx = ctx.CreateMemento();
var target = builders.Concat(ctx.AdditionalBuilders).Select(b => b(ctx)).Sum();
if (ctx.CoverOnly != null)
{
target = ctx.CoverOnly + ctx.ChangeAmount;
}
var selection = CoinSelector.Select(coins, target);
if (selection == null)
{
throw new NotEnoughFundsException("Not enough fund to cover the target");
}
var total = selection.Select(s => s.Amount).Sum();
var change = total - target;
if (change < Money.Zero)
{
throw new NotEnoughFundsException("Not enough fund to cover the target");
}
if (change > ctx.Dust)
{
if (group.ChangeScript[(int)ctx.ChangeType] == null)
{
throw new InvalidOperationException("A change address should be specified (" + ctx.ChangeType + ")");
}
ctx.RestoreMemento(originalCtx);
ctx.ChangeAmount = change;
try
{
return(BuildTransaction(ctx, group, builders, coins));
}
finally
{
ctx.ChangeAmount = Money.Zero;
}
}
foreach (var coin in selection)
{
var input = ctx.Transaction.AddInput(new TxIn(coin.Outpoint));
if (_LockTime != null && _LockTime.HasValue && !ctx.NonFinalSequenceSet)
{
input.Sequence = 0;
ctx.NonFinalSequenceSet = true;
}
}
return(selection);
}
private IEnumerable<ICoin> BuildTransaction(
TransactionBuildingContext ctx,
BuilderGroup group,
IEnumerable<Builder> builders,
IEnumerable<ICoin> coins,
IMoney zero)
{
var originalCtx = ctx.CreateMemento();
var target = builders.Concat(ctx.AdditionalBuilders).Select(b => b(ctx)).Sum(zero);
if(ctx.CoverOnly != null)
{
target = ctx.CoverOnly.Add(ctx.ChangeAmount);
}
var unconsumed = coins.Where(c => ctx.ConsumedCoins.All(cc => cc.Outpoint != c.Outpoint));
var selection = CoinSelector.Select(unconsumed, target);
if(selection == null)
throw new NotEnoughFundsException("Not enough fund to cover the target",
group.Name,
target.Sub(unconsumed.Select(u => u.Amount).Sum(zero))
);
var total = selection.Select(s => s.Amount).Sum(zero);
var change = total.Sub(target);
if(change.CompareTo(zero) == -1)
throw new NotEnoughFundsException("Not enough fund to cover the target",
group.Name,
change.Negate()
);
if(change.CompareTo(ctx.Dust) == 1)
{
var changeScript = group.ChangeScript[(int)ctx.ChangeType];
if(changeScript == null)
throw new InvalidOperationException("A change address should be specified (" + ctx.ChangeType + ")");
if(!(ctx.Dust is Money) || change.CompareTo(GetDust(changeScript)) == 1)
{
ctx.RestoreMemento(originalCtx);
ctx.ChangeAmount = change;
try
{
return BuildTransaction(ctx, group, builders, coins, zero);
}
finally
{
ctx.ChangeAmount = zero;
}
}
}
foreach(var coin in selection)
{
ctx.ConsumedCoins.Add(coin);
var input = ctx.Transaction.Inputs.FirstOrDefault(i => i.PrevOut == coin.Outpoint);
if(input == null)
input = ctx.Transaction.AddInput(new TxIn(coin.Outpoint));
if(_LockTime != null && !ctx.NonFinalSequenceSet)
{
input.Sequence = 0;
ctx.NonFinalSequenceSet = true;
}
}
return selection;
}
public TransactionBuildingContext CreateMemento()
{
var memento = new TransactionBuildingContext(Builder);
memento.RestoreMemento(this);
return memento;
}