Now that GtkATContext is explicitly realized and unrealized, we should
always create an instance at widget initialization time, and drop it
during the widget finalization. This should make it easier to set up the
initial accessible state of a widget during the instance initialization,
as well as reduce the chances of accidental creation of GtkATContext
instances during the destruction sequence.
Since GtkATContexts are now lazily realized, we need to go through the
GtkAccessible's implementation to access the :accessible-role property,
in case there are fallbacks.
There's no need to do a lot of work on construction, if we're delaying
all remote work after the GtkATContext is realized.
The GtkAtSpiContext should also keep a reference on the root, and drop
it at unrealize time.
By unrealizing the context we avoid additional work during the dispose
phase, in case widget code updates the accessible state. We use
GtkAccessible's API, to ensure we unrealize the right ATContext, instead
of the one we store inside GtkWidgetPrivate.
We drop the ATContext instance inside GtkWidget during finalization, to
mop up eventual vivifications there.
For builds that do not have PangoFT2, the demo fails to link because we weren't
building listview_ucd.c. Fix the build by building listview_ucd.c with
script-names.c and unicode-names.c for all builds, as we now require a Pango
version that already always depends on HarfBuzz and those sources do not use
anything from PangoFT2.
gtk-builder-tool simplify --3to4 now produces a
<requires lib="gtk" version="4.0"/>.
Adapt for that, and also add some tests that check that we
actually verify the requires, and accept 3.99 and 4.0, but
not 5.x.
The hypothetical widget that needs to clone ATContext instances
because it needs to control the accessible role post-construction is
really GtkModelButton.
Fixes: #3342
Some widgets might want to override GtkAccessible and create their own
context in order to control the accessible role post-construction time.
To avoid explicitly copying the existing state over from the original
ATContext to the new one, we need a way to clone the context's state
from inside the ATContext itself.
Using GList is a bit lame, and makes the API more complicated to use
than necessary in the common case.
The only real use case for a GList is gtk_widget_add_mnemonic_label(),
and for that we can use the GValue-based API instead.
Fixes: #3343
The accessible-role property in GtkWidget has three possible targets:
- the :accessible-role of a GtkATContext, if realized
- the accessible_role field of GtkWidgetPrivate
- the accessible_role field of GtkWidgetClassPrivate
When we set the accessible role of a widget using the GObject property
mechanism, we want to either set the GtkWidgetPrivate.accessible_role
field, if there's no ATContext *or* if the ATContext is not realized.
Conversely, when we get the accessible-role property we want to have a
series of fallbacks in place:
- if GtkAccessible.get_at_context() returns an ATContext, and that
ATContext is realized, return the :accessible-role of the context
- if GtkWidgetPrivate.accessible_role is not WIDGET, return the
stored accessible role
- return GtkWidgetClassPrivate.accessible_role
This should help catch the case of getting the accessible role of
widgets that override GtkAccessible.get_at_context(), like
GtkModelButton.
See: #3342
