protected IIterator TokensOf(DataCache snapshot, UInt160 owner)
{
NFTAccountState account = snapshot.TryGet(CreateStorageKey(Prefix_Account).Add(owner))?.GetInteroperable <NFTAccountState>();
IReadOnlyList <byte[]> tokens = account?.Tokens ?? (IReadOnlyList <byte[]>)System.Array.Empty <byte[]>();
return(new ArrayWrapper(tokens.Select(p => (StackItem)p).ToArray()));
}
protected bool Transfer(ApplicationEngine engine, UInt160 to, byte[] tokenId)
{
if (to is null)
{
throw new ArgumentNullException(nameof(to));
}
StorageKey key_token = CreateStorageKey(Prefix_Token).Add(GetKey(tokenId));
TokenState token = engine.Snapshot.TryGet(key_token)?.GetInteroperable <TokenState>();
UInt160 from = token.Owner;
if (!from.Equals(engine.CallingScriptHash) && !engine.CheckWitnessInternal(from))
{
return(false);
}
if (!from.Equals(to))
{
token = engine.Snapshot.GetAndChange(key_token).GetInteroperable <TokenState>();
StorageKey key_from = CreateStorageKey(Prefix_Account).Add(from);
NFTAccountState account = engine.Snapshot.GetAndChange(key_from).GetInteroperable <NFTAccountState>();
account.Remove(tokenId);
if (account.Balance.IsZero)
{
engine.Snapshot.Delete(key_from);
}
token.Owner = to;
StorageKey key_to = CreateStorageKey(Prefix_Account).Add(to);
account = engine.Snapshot.GetAndChange(key_to, () => new StorageItem(new NFTAccountState())).GetInteroperable <NFTAccountState>();
account.Add(tokenId);
OnTransferred(engine, from, token);
}
PostTransfer(engine, from, to, tokenId);
return(true);
}
protected void Mint(ApplicationEngine engine, TokenState token)
{
engine.Snapshot.Add(CreateStorageKey(Prefix_Token).Add(GetKey(token.Id)), new StorageItem(token));
NFTAccountState account = engine.Snapshot.GetAndChange(CreateStorageKey(Prefix_Account).Add(token.Owner), () => new StorageItem(new NFTAccountState())).GetInteroperable <NFTAccountState>();
account.Add(token.Id);
engine.Snapshot.GetAndChange(CreateStorageKey(Prefix_TotalSupply)).Add(1);
PostTransfer(engine, null, token.Owner, token.Id);
}
public IIterator TokensOf(StoreView snapshot, UInt160 owner)
{
if (owner is null)
{
var results = snapshot.Storages.Find(new[] { Prefix_Token }).GetEnumerator();
return(new StorageIterator(results, FindOptions.ValuesOnly | FindOptions.DeserializeValues | FindOptions.PickField1, null));
}
else
{
NFTAccountState account = snapshot.Storages.TryGet(CreateStorageKey(Prefix_Account).Add(owner))?.GetInteroperable <NFTAccountState>();
IReadOnlyList <byte[]> tokens = account?.Tokens ?? (IReadOnlyList <byte[]>)System.Array.Empty <byte[]>();
return(new ArrayWrapper(tokens.Select(p => (StackItem)p).ToArray()));
}
}
private protected void Burn(ApplicationEngine engine, StorageKey key)
{
TokenState token = engine.Snapshot.TryGet(key)?.GetInteroperable <TokenState>();
if (token is null)
{
throw new InvalidOperationException();
}
engine.Snapshot.Delete(key);
StorageKey key_account = CreateStorageKey(Prefix_Account).Add(token.Owner);
NFTAccountState account = engine.Snapshot.GetAndChange(key_account).GetInteroperable <NFTAccountState>();
account.Remove(token.Id);
if (account.Balance.IsZero)
{
engine.Snapshot.Delete(key_account);
}
engine.Snapshot.GetAndChange(CreateStorageKey(Prefix_TotalSupply)).Add(-1);
PostTransfer(engine, token.Owner, null, token.Id);
}
