Added new syscalls - GetInvocationCounter and GetNotifications

[igormcoelho]

@belane you will need this for NEP-5

[igormcoelho]

Can you please try to use it @belane? To see if it's responding correctly... like first invocation of kind.. second invocation.. etc. "mint" should be done only once, to simplify implementation.

[igormcoelho]

Ah, it's breaking by format now... could you run a dotnet format for us @belane? when you have time please, during your tests.

P.S.: that's the first proof that the travis is working well to keep formats well-done 💪

[shargon]

Also, could you add the notifications?

[shargon]

GetNotifications was added, but require to be tested because i am not sure if it works xD

https://github.com/neo-project/neo/blob/c04ee5d277f522eb42bc8fc6a792b0aedf6ab0fc/neo/SmartContract/InteropService.cs#L237

[igormcoelho]

On GetNotifications, best solution now, in my opinion, is to return an object[], where first element is scripthash, and second is state. This corresponds to the internals used right now. A better solution is, in the future, create an Interop object just for notifications, so we can improve devpack a little bit more.

[igormcoelho]

I don't think this works, and it doesn't makes sense to inherit from IScriptContainer, bacause Notification is not a ScriptContainer.

[igormcoelho]

Need to adjust into object[] pair.

[erikzhang]

@igormcoelho I think we can revert the last commit. I believe that returning Notifications is also working. Let's test it.

[igormcoelho]

Erik, I agree it could work, but it's a very unsafe side effect to rely on. If we want Notification to have its own life, we should create an Interop object for it, not treat it as an Array. At best scenario, it would be a Struct, not an Array... if that's intended perhaps we can create a Struct stack item on Notifications push, that's slightly better.... I mean, if it's worth risking, let's do it

// as struct
engine.CurrentContext.EvaluationStack.Push(notifications.Select(u => new VM.Types.Struct(new StackItem[] { u.ScriptHash.ToArray(), u.State })).ToArray());
            
// instead of array
engine.CurrentContext.EvaluationStack.Push(notifications.Select(u => new VM.Types.Array(new StackItem[] { u.ScriptHash.ToArray(), u.State })).ToArray());
            

For me it's good to revert, I'm just saying, it's not 100% correct in my opinion.

[erikzhang]

What risk do you mean?

We convert class and array into Array in NeoVM, and convert struct into Struct.

[igormcoelho]

We convert class and array into Array in NeoVM

I never thought this was official (for class), but a side effect. I always thought of class and struct to be equivalent to Struct. In this case I'll revert the commit.

[shargon]

We need to deal with the class, because is easier for devs.

[shargon]

Maybe need to be a struct?

[igormcoelho]

@belane please confirm that this works for NEP-5 template... as Erik said, if class and array are equivalent for NeoVM, this should be fine.

[shargon]

I will make some unit test for both syscalls

[vncoelho]

@erikzhang, it is quite confusing like this.

We used to consider that struct is also a class when programming in C++. How is it in C#?

Perhaps we could remove the struct and then consider everything as an array

[shargon]

Added unit test, it not works :( but you can play with it xD
@lightszero any idea ?

[shargon]

The problem was because property is a method, with variables, works perfect!

[igormcoelho]

Are tests still broken? I'll take a look.

[shargon]

Formatted done!

[vncoelho]

Still something:

 Error Message:
   CollectionAssert.AreEqual failed. (Different number of elements.)
  Stack Trace:
     at Neo.SmartContract.Framework.UnitTests.UT_OpcodeTest.TestAllOpcodes() in /home/travis/build/neo-project/neo-devpack-dotnet/tests/Neo.SmartContract.Framework.UnitTests/UT_OpcodeTest.cs:line 17

[shargon]

#99 solve the issue, but i think that UTF8 was not cleaned in this project

[shargon]

Is fixed (i think) Thanks @vncoelho for the format

[erikzhang]

We used to consider that struct is also a class when programming in C++. How is it in C#?

They are quite different in C#.