GSoC 2024: Week 3-4 Report

GSoC 2024: Week 3-4 Report 


Add support for the latest GIR attributes and GI-Docgen formatting to Valadoc


Lorenz Wildberg

Week 3 : default-value attribute for property

Parsing the "default-value" attribute into a member access: In continuation of the work done previously, we tried to set the prop.initializer of the corresponding Vala.Property from the default-value attribute by parsing it as an enumerator member. We parsed the default-value into a member access in GirParser.process(), but trying to regenerate the bindings resulted in errors like this:

We got these errors because the default-value attribute in the vala GIRs actually contains the "c:identifier" of the enum member. However the function   parse_enumeration_member() in the GirParser parses it into an EnumValue using its "name" attribute and not the "c:identifier" attribute. Thus when we try to parse the default-value attribute into a member access, the parser cannot find any enum member corresponding to the value in the default-value attribute:

  The enum member with c:identifier="GTK_FILE_CHOOSER_ACTION_OPEN" is parsed with the name "open"

A temporary workaround is to parse enum members using their "c:identifier" attribute so that the value of the "default-value" attribute is the same as the symbol name of the EnumValue (the name of the symbol would now be the "c:identifier" of the enum member). This would fix the above error but it would also change the names of all enum members in the bindings to the value of their corresponding "c:identifier". This might be risky, so we are working on finding a viable solution that does not cause any breaking changes. Furthermore, we are also working on cases where the "default-value" attribute has two enum members separated by a binary OR - an example of this is in line 64623 in Gtk-4.0.gir :


Here, the default-value cannot be parsed into a single enum member because it contains two members of type Gtk.FontChooserLevel.With the resolution of the above error and some minor tweaks, we will be able to successfully parse the default-value attribute into the bindings.

Week 4: glib:finish-func attribute for method

In the GirParser: In the previous week, we added a new property, finish_func in Vala.Method and set this property to the value of glib:finish-func. To further refine the support for this attribute, we used the finish_func property to decide whether the method is asynchronous, as there is currently no definitive rule for this in the GirParser. Since only async functions in GObject can have the glib:finish-func attribute, a method is async if it's finish-func property is not null. We added this feature, and then added a test case in tests/gir/method-class.gir to check whether a method with this attribute is declared as asynchronous in the bindings.

In the GirWriter: Further improvement was done to add the support for glib:sync-func, glib:async-func,and glib:finish-func in:
  • Synchronous methods: Made the GirWriter write the glib:async-func attribute if the method is synchronous and has a corresponding asynchronous version.
  • Asynchronous methods: Made the GirWriter write the glib:sync-func attribute if the method is asynchronous (and has a corresponding synchronous version), and the glib:finish-func attribute.
This involved making tweaks in the write_signature and do_write_signature methods because they write the GIR attributes for method. Finally, we updated the test cases in tests/girwriter to test these changes.

So this was the summary of our work in the previous two weeks. Thanks for reading :). In the coming days we plan to work on Valadoc and add support for the remaining GObject Introspection attributes!


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