Avoid use of pb.Data

[overbool]

see ipfs/kubo#5217 (comment)

[overbool]

@schomatis In order to use pb.Data's functions, I add Format() to receiver FSNode as follow:

// Format returns the format inside this node
func (n *FSNode) Format() *pb.Data {
	return &n.format
}

But, Format() is confusing or not so good.

WDYT?

[schomatis]

Why would you need that? (I'm not sure I follow.) The idea behind FSNodeFromBytes was to avoid direct manipulation of pb.Data (and hence its format).

[overbool]

it will call GetFilesize() somewhere that is a pb.Data function.

Did you mean that we could wrap the GetFilesize() or maybe other pb.Data functions to avoid direct manipulation of pb.Data.

just like:

func (n *FSNode) GetFilesize() uint64 {
	return n.format.GetFilesize()
}

[schomatis]

Did you mean that we could wrap the GetFilesize() or maybe other pb.Data functions to avoid direct manipulation of pb.Data.

Yes, because actually you wouldn't have pb.Data objects laying around in the code anymore, you would just have the FSNode type. However, if you see a case where we definitely need to use pb.Data please point me to it and we'll evaluate it.

[overbool]

@schomatis ok, I misunderstood you at first。

in my own view, wrapping all pb.Data functions maybe is a good idea that we can absolutely avoid direct manipulation of pb.Data.

[schomatis]

Fixed in #18.