[Development] Untangling our platform plugins

[Oswald Buddenhagen]

On Fri, May 15, 2020 at 09:20:26AM +0000, Tor Arne Vestbø wrote:
>But for the ones that live in qtbase, the majority of their code would 
>be moved to the relevant modules, leaving only the plugin’s entry point 
>as a shared library.
>
having a significant part of the plugin's implementation (if not most of 
it) linked into the parent library leads the concept of "plugin" ad 
absurdum.

>Or, in the case of platforms such as macOS where there’s only one 
>“platform”, the plugin is built directly into QtGui as a static plugin.
>
the logical consequence of the above would be statically linking the 
plugins on all platforms. or, for that matter, throwing out the pretense 
of plugins and just make it a regular factory, to the degree it even 
makes sense at all.

the alternative would be building the "platform addons" as separate 
libraries to which the plugins and interested user code may link. note 
that this implies that the parent libraries may not use any of the 
functionality directly - that would imply finally creating platform 
plugins per library, rather than cramming everything into qtgui's qpa 
plugins. it's debatable whether this granularity is desirable, though 
(now that "everyone" has an ssd, having many small libraries isn't that 
painful anymore, but still).