Hi Gabriel,
On 10/21/19 1:40 PM, Gabriel Ivăncescu wrote:
The heap stores dynamic global variables added during the execution phase. We'll need to reference them in the TypeInfo, and so we have to reference count the heap itself, and the simplest way is to use the script dispatch object to store it.
It seems to me that you concentrated a bit too much at avoiding copying the data rather than on root of the problem. It's possible to avoid copying in different ways. The thing is that having to represent the collection of global members in different ways for similar tasks probably means that representation of the collection is not right. Actually, we know that current global scope representation is not great. A simple list was nice to have things done and working, but it's surely not optimal. I don't expect you to rewrite it all, but it will be eventually rewritten and it would be good to know that we're changing things in the right direction instead of working on something that will need to be rewritten for future improvements.
I don't know exactly how it should look like. It's even possible that we will have to do some copies to capture the state after all. If I was looking at it, I'd start with more experimentations. Your tests seem like a good start. It would be interesting to see how things change when you add more global members later. You tested that adding new global variables doesn't change the existing ITypeInfo. How does the new one look like? Does it append new variables after previous ones? What if we added a new "dynamic" (non-explicit) variable? What if we mix it all? How about functions? What do DISPIDs look like? Is it reasonable to try to replicate native DISPIDs? Once we know more answers, we may decide how the collection should look like.
Once we know that, we should consider how to replace existing storage with something suitable for ITypeInfo. The new collection would need to be available for the interpreter and script dispatch (its GetIDsOfNames should probably share the implementation with ITypeInfo one). script_ctx_t may indeed be a good place. Another option could be ScriptDisp or maybe another new struct. Note that we currently ignore the case of closed script engine in other places (with things like if(!This->ctx) return E_UNEXPECTED; in GetDispID) and until it's a problem for an actual application, feel free to do a similar thing (preferably with a FIXME). If we have to fix it, script_ctx_t is intentionally done in a way that would be easy to make it ref-counted. For that, however, it would be nice to see how both ITypeInfo, script dispatch IDispatchEx and VBS class instance IDispatchEx behave on closed script engines. Then we can decide how much of it do we want to keep after releasing script engine itself.
Thanks,
Jacek