WIP: Refactor Value and Property handling

[sdroege]

This will handle https://github.com/gtk-rs/glib/issues/667 and https://github.com/gtk-rs/glib/issues/637

[sdroege]

For signals we can probably have some associated trait function that passes in some kind of "signal creation context" plus a builder-style API on it for making it easier to create signals. I'll experiment with that too.

[sdroege]

Initial WIP version of the Value traits refactoring is here now. Needs all the impls to be updated and to be confirmed that it actually works correctly everywhere.

Some feedback on the traits would be useful already.

[sdroege]

Some feedback on the traits [in the last WIP commit] would be useful already.

@fengalin maybe from you? :)

[fengalin]

I'll take a look later today (afk atm). It seems like a neat improvement indeed.

[sdroege]

I'll take a look later today (afk atm). It seems like a neat improvement indeed.

Thanks, no need to hurry :) The goal is basically to have a direct mapping between types, param specs and the Value API. Based on that we can derive subclass property handling code (the pspecs and getters/setters just based on the type), signal handler code (automatic Value <-> Rust type conversion for the parameters) and other nice things that are currently not possible.

[sdroege]

src/value.rs should be finished now except for the TODO comments (implementing ownership transferring TryFrom<Value> for T and From<T> for Value).

Overall there is more code to implement per type now for working with Values, but at least the majority of the cases for this are going to be covered by the glib_wrapper! macro (objects, boxed, shared) and gir (src/auto/flags.rs and src/auto/enums.rs). Nonetheless, if someone has an idea how to simplify it, please let me know.

[fengalin]

I only looked rapidly so far. Will take a deeper dive tomorrow hopefully.

[sdroege]

Ok, no further comments here so I proceed :)

[sdroege]

Ok, next step is to update gir and then the other crates and then get all tests pass 😴

[sdroege]

I wonder if I should split this PR so that part of it can already get in and doesn't bitrot while I need more time to finish the other parts.

The changes to the property handling can go in already and are useful and nice separately too. @bilelmoussaoui @GuillaumeGomez opinions?

[sdroege]

I'm working currently on finishing this btw. The next PR is going to have the refactored traits but none of the new pspec-related traits yet (I think we'll want to keep them for the release afterwards).

[sdroege]

I have glib compiling again, and gio and cairo and pango and pangocairo. gdk/gtk need some updates still, and atk is a bit annoying because it has an enum called ValueType which conflicts with the same-named trait from glib :)

[sdroege]

Current WIP is at #454

[sdroege]

Let's close this one for now.