[Feature]: Allow Storage Commands to Issued After Component Execution

[kouchekiniad]

Feature Overview

This feature request is to add a means by which components can add configuration or services after its entry point has existed, such as in event callbacks. So far as I can tell, there is currently no reasonably safe way to do this. One major application of this feature would to allow components to publish services that wrap around EDKII protocols, which could only be done once that EDKII protocol has been published.

Solution Overview

In progress.

One possible solution would to take Storage's Deferred out of Option<> (and make the queue shared between components) and to provide some form of locking and interior mutability that would allow the Commands parameter to be cloned and passed to event contexts.

Another possible solution would be to add a new Protocol<uefi_protocol::ProtocolInterface> parameter that is marked as valid once the associated protocol GUID has been installed. This would make the solution specific to the case where a service is installed once a protocol has been installed.

Alternatives Considered

No response

Urgency

Low

Are you going to implement the feature request?

I will implement the feature

Do you need maintainer feedback?

Maintainer feedback requested

Anything else?

No response

[Javagedes]

I have a working implementation of Param on a Protocol<P: Protocol> struct as you described above.

We were reluctant to publicize it as it encourages people to use the protocol directly instead of a service.

This issue here would be the main use case for such a param type. E.g. stopping a component that produces a service backed by a protocol from executing until that protocol has been produced)

Please also keep in mind that the Param trait is public and anyone can create their own implementation outside of the patina crate.

The intent is to eventually create a patina event, but until that happens I want to prevent the intermixing of the patina component interface and the EDKII system. Since we have a good solution with the Param implementation, which will prevent a component from executing until a protocol is ready, that is my preferred route.

Whether we make the generic implementation available, or tell users they need to implement it themselves, is up to debate

[kouchekiniad]

Hi @Javagedes, I'm taking a look at this again after having to step away for a while. My main concern here is that publishing a component in the Patina repo that includes an implementation of Protocol<P: Protocol> param makes that new param type publicly accessible. I can't seem to find any way of defining a new param type that isn't pub.

[Javagedes]

I'm not sure what you mean. Param trait implementations can be done from any crate and can be private to that crate so long as the component using that param implementation is in that crate.

Can you provide more context / example?