This is mainly an attempt to merge the update_style() and validte()
vfuncs. Code is not there yet, but that's the idea.
Also, gtk_css_node_set_style() should not be public. And this gets
closer to that goal, too.
After measuring it, I realized the optimization never triggers for
Adwaita and rarely ever triggers for simple themes. So it is not
useful to keep it around.
This allows adding more API for it.
It also includes code that tracks modifications and invalidates siblings
and their positions whenever nodes get added or removed.
The node declaration has the same functionality as
gtk_css_node_declaration_add_to_widget_path(). So instead of using that
function on a path, you can use the original path and the declaration in
a matcher.
So far the vfunc is kinda quirky (the path argument is an out argument
for something you have to free when you're done with the matcher), but
I'm about to change that.
The parent refs the child, so gtk_css_node_set_parent() adds/removes a
reference.
We should probably refactor this so that we name the function
parent.add(node) instead of node.set_parent(parent) - makes the
refcounting more clear.
- GtkCssWidgetNode
for style contexts owned by a widget
- GtkCssPathNode
for style contexts using a GtkWidgetPath
- GtkCssTransientNode
for nodes created with gtk_style_context_save()/restore()
The functionality of it is supposed to grow, so better put it in a
custom file early.
This is just a naive split so far, the next patches will split things
further.
