Simplify interop services

[erikzhang]

Summary
Currently, our interop service API is very complicated. For example, to get a transaction, we need to call System.Blockchain.GetTransaction and then call Neo.Transaction.GetScript to get the fields of the transaction. Maybe we can simplify them.

Solution
In fact, we have an API that is very simple, that is System.Runtime.GetNotifications.

neo/neo/SmartContract/InteropService.cs

Lines 237 to 252 in 2da4fb1

	private static bool Runtime_GetNotifications(ApplicationEngine engine)
	{
	byte[] data = engine.CurrentContext.EvaluationStack.Pop().GetByteArray();
	if ((data.Length != 0) && (data.Length != UInt160.Length)) return false;
	IEnumerable<NotifyEventArgs> notifications = engine.Notifications;
	if (data.Length == UInt160.Length) // must filter by scriptHash
	{
	var hash = new UInt160(data);
	notifications = notifications.Where(p => p.ScriptHash == hash);
	}
	if (!engine.CheckArraySize(notifications.Count())) return false;
	engine.CurrentContext.EvaluationStack.Push(notifications.Select(u => new VM.Types.Array(new StackItem[] { u.ScriptHash.ToArray(), u.State })).ToArray());
	return true;
	}

We can change all the APIs that get the data into this way. This way we can remove a lot of redundant APIs.

Where in software does this update applies to?

• SDK
• Other: NeoContract

[shargon]

Totally agree, we should follow this way

[shargon]

I will change this #1081 in order to fit your pattern, it could save a lot of opcodes

[igormcoelho]

Fully agree Erik, as long as Array behaves as Object, this will be fine.