[Geany-Devel] My non-C plugin roadmap

[Thomas Martitz]

Hello,

some if your question are easier to answer by looking at the code, I'll 
link the appropriate sections.


Am 30.03.2015 um 13:16 schrieb Lex Trotman:
> [...]
>
> Ok, this explains some of what I was asking on the other thread, so
> now I can ask the more specific questions below that are the key
> points in the confusion.
>
>> with my new loader (no pluxies) it goes like this, and this is *very*
>> similar to git master.
>>
>>> user opens PM dialog
>> 1 Geany calls load_all_plugins(), which calls load_plugins_from_path($path)
>> 2 for each $file in $path, Geany checks if the extension is G_MODULE_SUFFIX,
>> and calls plugin_new($file, ...)
>> 3 plugin_new() calls the plugins's  geany_load_module() (if new-style
>> plugin, calls version_check, set_info() for old-style ones)
>> 4 geany_load_module() is implemented by the plugin, and registers itself
>> with geany_plugin_register()
>> < geany_plugin_register() adds the plugin to the plugin list, so that the PM
>> can sort and show it
>>
>> Now, with pluxies, it is completely the same except for:
>> 2* for each $file in $path, Geany calls is_plugin($file)
> What is is_plugin()? If its a function in Geany how does it get to
> know about new types of plugins without being hard coded?


It's new, small helper function I added. It loops through all known file 
extensions, and returns the first pluxy (a PluginProxy *) for which a) 
the supported file extension matches and b) the probe hook returned true 
(or is NULL, for standard plugins).
$file is not a plugin if is_plugin returns NULL, i.e. no pluxy was found.

https://github.com/kugel-/geany/blob/pluxy/src/plugins.c#L844


File extensions and the proxy hooks (probe, load, unload) are registered 
by a plugin during its init() through the new plugin_register_proxy() 
function. Here the pluxy added to the list of registered pluxies. This 
list is initialized with the simulated pluxy that provides standard 
plugins (this is not a plugin, it's contained in plugins.c, it's just to 
keep the code paths equal).

https://github.com/kugel-/geany/blob/pluxy/src/plugins.c#L1601

>
>> which matches
>> additional file extensions (as provided by pluxies), it also calls the
>> probe() hook to resolve ambiguous files (e.g. .so files, they can be core or
>> libpeas plugins)
> I'm guessing probe() is a function that looks for something in the .so
> that distinguishes if its new or old loader, but what about others?


It depends on the pluxy what the prope() function does! For my peasy 
pluxy (that provides generic support for libpeas-based plugins), it 
looks if there is a matching *.plugin for a given *.so, and if yes 
return a code so that Geany does not attempt to process the .so itself.

https://github.com/kugel-/peasy/blob/master/src/peasy.c#L73

There is no probe() for standard plugins, it accepts all .so. Whether 
it's a new or old style plugin is determined later. It *could* be in a 
probe() hook for standard plugins as well, I just didn't happen to 
implement it that way (yet), because plugin_load_so needs to distinguish 
between the two anyway.

https://github.com/kugel-/geany/blob/pluxy/src/plugins.c#L472

>
>> 3* plugin_new() calls the load() hook registered by pluxies for the given
>> extension. for standard plugins (without proxy) there is a predefined
>> plugin_load_so() funtion that gets called instead.
> How does the load hook get defined for new types of plugins?

Via the new API function plugin_register_proxy().
https://github.com/kugel-/geany/blob/pluxy/src/plugins.c#L1601

>
>> 4* The load-hook calls geany_plugin_register(), here Geany core and proxies
>> work the same way
> Where is the geany_plugin_register() defined for a plugin written in a
> language that isn't C/C++/Vala that can produce a .so file?

In the load hook of the pluxy. Either the pluxy calls it directly or it 
decides to provide a suitable binding so that the non-C script can call 
it itself, but it has to be during the execution of the load hook.

The demopluxy does it in the load() hook, right after parsing the 
metadata of the example plugin (I completely made up a fake plugin 
format for demonstration purposes):

https://github.com/kugel-/geany/blob/pluxy/plugins/demopluxy.c#L169

I have done it the same way for peasy too, because libpeas plugins can 
be python or js, and I didn't create bindings yet. But it shows working 
this way.

https://github.com/kugel-/peasy/blob/master/src/peasy.c#L130


>
>> I designed it such, that the difference between standard plugins and proxied
>> plugins is all contained in the load hook. The rest of Geany does not know
>> about the difference. This ensures proxied plugins are first class citizens.
>>
> Thats the correct target I agree, I just don't understand the design
> details yet.
>

Thanks for the heads up!

Best regards