Lists of Native Arrays and Disposing

So I've got an interesting result.

First I copy a native array over. It's my understanding that calling new NativeArray will create a deep copy of the Native Array instead of copying the reference.

Code (CSharp):

1. for(int i = 0, l = successList.Count; i < l; i++)
2. {
3.     tempSuccessList.Add(new NativeArray<bool>(succesList[i], Allocator.TempJob));
4. }
5.  
6.  

And then later to dispose of this newly copied array, I call on

Code (CSharp):

1.  
2. private void ClearTempResultsList()
3. {
4.     for(int i = 0, l = tempSuccessList.Count; i < l; i++)
5.    {
6.       if(tempSuccessList[i].IsCreated)
7.          tempSuccessList[i].Dispose();
8. }

And then when I call the above code, IsCreated is returned as true, but I am unable to dispose of the floorTempSuccess saying that tempSuccessList was already disposed (which the original successList was disposed).

Why is IsCreated true if the object has already been disposed?

 

Well, I am a bit of a dummy. I was forgetting to clear the list after I disposed each array.

Although I still think if you call IsCreated on a disposed native array it should return false. Is this not the intended behaviour?

 

Oh shoot, yes it is.

Is there a way to hold a list of NativeArrays without messing something up and being able to access the direct data? I thought that the NativeArray was a reference that you can pass around. I need to have many native arrays in a list that I run parallel jobs over and then later dispose them. Always on the main thread, so I am not passing the list into a job.

 

Unfortunately yes. I need to be able to keep adding to the list as needed. I could probably write a wrapper to treat it as a array and expand the array when needed, but that is a bit of a pain. Although for whatever reason, I am not getting any disposal errors now. So it looks like I am successfully clearing as the NativeArrays I've made.

Is there any chance the Disposal Sentinel isn't finding these extra arrays?

 

Oh heck yeah, this is perfect. That makes total sense. I am still a bit shaky on how Native Arrays are stored but this is exactly why IsCreate is returning true while I am still able to dispose the list.

Thanks so much!

 

I have another question about NativeArrays. I want to extend NativeArray to a new native Array called NativeArrayList. Basically NativeList, but with the ability to insert and a few of the other options that List<> has in C#.

I've already implemented it a bit as a struct with an underlying NativeArray which I resize and dispose as needed. Am I doing this the right way? I sometimes get weird situations like those of above where I call on the underlying list as being created but then throws an error when I try to dispose the underlying array.

I guess my question is what is the best way to extend NativeArrays and write my own type?

Should I be looking at this instead of making a struct wrapper?

https://www.jacksondunstan.com/articles/4734

 

Oh wow, those extensions were exactly what I was looking for. I am trying to keep my code really simple so it can be used even with older versions of Unity (2019) so I wasn't pulling in any fancy lists or what have you.

I was just using lists on the main thread, not putting them into jobs. I would convert into a NativeArray before jobifying them. I started with Burst a year and a bit ago, so I am sure the features have grown since I last looked into NativeList.

Am I able to wrap a NativeArray in another struct (Native Array lives inside the struct) or will this cause major issues with copying and moving data around?