Use the same initial check for the accessible object type that we use
when connecting the signal, in case we try to disconnect signals on
different widgets. Additionally, check before accessing data that might
have already been removed.
Fixes: #3403
The accessibility bus might not be available, and if it isn't the case,
it means something has failed at a level where the user can't do much
about it. There's no need to emit a critical warning.
If the accessible object is hidden, we can skip the emission of the
AddAccessible and RemoveAccessible signals on the cache, as those
objects won't be visible in the accessibility tree.
The GtkAtSpiContext is responsible for removing itself from the root,
which will remove itself from the cache. Any code path that leads to the
GtkAtSpiContext instance being collected passes through the
unrealization phase, which will also unregister the context from the
accessibility bus and from the cache.
When falling back to using the program name to create a unique base path
for the objects on the accessibility bus we need to ensure that the name
is a valid DBus object path.
The AT-SPI cache interface is used to quickly populate the accessible
objects tree.
The tricky bit is ensuring that we emit change notifications on the
cache only when the cache is available, which means waiting until the
root is asynchronously registered.
The root path is shared by all AtSpiContext instances, so we should
compute it once, instead of every time we instantiate a new context.
This allows us to defer the path creation at realization time and ensure
that we have a registered application.
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.
We are doing too much work during the construction phase of the
AT-SPI backend for GtkATContext. Instead of having the AtSpiContext
register itself at construction time, let's add explicit realize
and unrealize operations, and connect the ATContext realization to the
rooting operation of a GtkWidget.
Instead of monitoring the list of toplevels, rely
on GtkWindow updating the HIDDEN state before windows
get removed. This is better, since we still have the
object available when it happens, so we can pass it
to the ATs.
When a toplevel window gets hidden (and not destroyed),
the frontend code set the HIDDEN state, and we need to
emit child notification when that happens.
We need to use gtk_accessible_should_present() whenever we
calculate accessible tree positions, to avoid inconsistencies.
While we are at it, make these helpers usable for finding
the position of accesibles that are now ignored, by not
looking at should_present for the object itself. This will
be relevant when we calculate the position of objects whose
HIDDEN state changes.
We need to translate the list model position into
an accessible tree position, since hidden toplevels
will be skipped.
While we are at it, add an api for this notification
that will be used in the next commit.
Hidden elements are not presented in the accessible
tree, so when then HIDDEN state changes, we should
emit child-added or -removed signals.
This commit does not yet handle all cases (HIDDEN
toplevels or hidden stack pages are not handled),
but it should cover the common case.
GtkModelButton is no longer derived from GtkButton,
but can still treat it like a button for the purposes
of having a click action. This lets ATs activate
menu items again.
GtkAtSpiRoot is not a context, which means it needs to emit
ChildrenChanged events by itself whenever a toplevel is added to, or
removed from, the list of toplevels.
The stack page objects were not properly integrated
in the accessible tree - they were appearing as parent
of the pages when navigating up, but not as children
of the stack when navigating down.
