Add TransformationStatus enum from corefxlab

[stephentoub]

Based on corefxlab work, will be used by a variety of new corefx Span-based APIs. We need to re-review to make sure it's exactly what we want to bake in to the core of the framework

namespace System.Buffers // System?
{
    public enum TransformationStatus // TransformStatus?  TransformResult?
    {
        Done, // Success? Complete? Ok?
        DestinationTooSmall,
        NeedMoreSourceData, // SourceTooSmall?
        InvalidData
    }
}

cc: @terrajobst, @bartonjs, @KrzysztofCwalina, @ahsonkhan

[mellinoe]

Regarding naming, I'd prefer the following:

• "TransformResult", or something with "Result" in the name
• "Success", rather than "Done"
• "SourceTooSmall" -- symmetry with "DestinationTooSmall"

[stephentoub]

I'd prefer the following

In case it wasn't obvious from my comments I added to the type, me too ;)

[KrzysztofCwalina]

I have used this enums in some contexts that were not transformations, e.g. in a routine that copies data from one buffer to another. Because of that, the currently proposed name is BufferOperationStatus, or even OperationStatus.

cc: @shiftylogic

[ahsonkhan]

the currently proposed name is BufferOperationStatus, or even OperationStatus.

Given the naming feedback:

"TransformResult", or something with "Result" in the name

Should the enum be named BufferOperationResult or OperationResult instead?

[KrzysztofCwalina]

I named it Status because I thought it implies current state of an ongoing operation (multiple calls to the method). Result to me implies more the final state.
But it might be splitting hair, and so I would be ok with either postfix

[karelz]

@KrzysztofCwalina I believe we are blocked on some of your TextEncoding APIs to show motivation for this one ...

[terrajobst]

Video

This is now tracked as part of other work item.

[ahsonkhan]

For reference, here is the enum now:
https://github.com/dotnet/corefx/blob/master/src/System.Memory/src/System/Buffers/OperationStatus.cs#L11

namespace System.Buffers
{
    public enum OperationStatus
    {
        Done,
        DestinationTooSmall,
        NeedMoreData,
        InvalidData,
    }
}

Are we happy with the field names as is?

[karelz]

Where is the main API approval issue? I can't find it ...

[karelz]

@ahsonkhan @KrzysztofCwalina what is the main API issue tracking the proposal now?

[karelz]

FYI: The API review discussion was recorded - see https://youtu.be/bHwCPVNQLwo?t=99 (4 min duration)