Add a fire-and-forget function to wait for shutdown to be complete.
It's not entirely trivial to ensure all resources of NMClient are
cleaned up. That matters only if NMClient uses a temporary GMainContext
that the user wants to release while the application continues. For
example, to do some short-lived operations an a worker thread. It's
not trivial also because glib provides no convenient API to integrate
a GMainContext in another GMainContext. We have that code as
nm_utils_g_main_context_create_integrate_source(), so add a helper
function to allow the user to do this.
The function allows to omit the callback, in which case the caller
wouldn't know when shutdown is complete. That would still be useful
however, when integrating the client's context into the caller's
context, so that the client's context gets automatically iterated
until completion.
The following test script will run out of file descriptors,
when wait_shutdown() is not used:
#!/bin/python
import gi
gi.require_version("NM", "1.0")
from gi.repository import NM, GLib
for i in range(1200):
print(f">>>{i}")
ctx = GLib.MainContext()
ctx.push_thread_default()
nmc = NM.Client.new()
ctx.pop_thread_default()
def cb(unused, result, i):
try:
NM.Client.wait_shutdown_finish(result)
except Exception:
# cannot happen
assert False
else:
print(f">>>>> {i} complete")
nmc.wait_shutdown(True, None, cb, i)
while GLib.MainContext.default().iteration(False):
pass
While iterating the context (once), multiple sources can be dispatched.
So if we get a timeout and shortly after the weak-ref callback, then
we still need to honor the weak-ref.
In particular, because weak_ref.unref() is not safe to do after
the object was already destroyed. So we need to be correct about
tracking destruction.
