"nm-macros-interal.h" already includes <errno.h> and <string.h>.
No need to include it everywhere else too.

We should no longer use nm_connection_for_each_setting_value() and
nm_setting_for_each_value(). It's fundamentally broken as it does
not work with properties that are not backed by a GObject property
and it cannot be fixed because it is public API.

Add an internal function _nm_connection_aggregate() to replace it.

Compare the implementation of the aggregation functionality inside
libnm with the previous two checks for secret-flags that it replaces:

- previous approach broke abstraction and require detailed knowledge of
  secret flags. Meaning, they must special case NMSettingVpn and
  GObject-property based secrets.
  If we implement a new way for implementing secrets (like we will need
  for WireGuard), then this the new way should only affect libnm-core,
  not require changes elsewhere.

- it's very inefficient to itereate over all settings. It involves
  cloning and sorting the list of settings, and retrieve and clone all
  GObject properties. Only to look at secret properties alone.

_nm_connection_aggregate() is supposed to be more flexible then just
the two new aggregate types that perform a "find-any" search. The
@arg argument and boolean return value can suffice to implement
different aggregation types in the future.

Also fixes the check of NMAgentManager for secret flags for VPNs
(NM_CONNECTION_AGGREGATE_ANY_SYSTEM_SECRET_FLAGS). A secret for VPNs
is a property that either has a secret or a secret-flag. The previous
implementation would only look at present secrets and
check their flags. It wouldn't check secret-flags that are
NM_SETTING_SECRET_FLAG_NONE, but have no secret.

On default log level we don't log anything when a new agent registers.
Let's raise the log level here, it doesn't add too much noise.

https://github.com/NetworkManager/NetworkManager/pull/174

This is a mere debugging convenience thing: e.g. if you run, but want to
check whether nm-applet or nmcli agent works fine, it's convenient that
the agent you run later gets a chance to deal with the secrets requests
first.

Is seems to do the job and is simpler that adding some more complicated
policy (e.g. introducing priorities or something).

https://github.com/NetworkManager/NetworkManager/pull/174

We commonly don't use the glib typedefs for char/short/int/long,
but their C types directly.

    $ git grep '\<g\(char\|short\|int\|long\|float\|double\)\>' | wc -l
    587
    $ git grep '\<\(char\|short\|int\|long\|float\|double\)\>' | wc -l
    21114

One could argue that using the glib typedefs is preferable in
public API (of our glib based libnm library) or where it clearly
is related to glib, like during

  g_object_set (obj, PROPERTY, (gint) value, NULL);

However, that argument does not seem strong, because in practice we don't
follow that argument today, and seldomly use the glib typedefs.
Also, the style guide for this would be hard to formalize, because
"using them where clearly related to a glib" is a very loose suggestion.

Also note that glib typedefs will always just be typedefs of the
underlying C types. There is no danger of glib changing the meaning
of these typedefs (because that would be a major API break of glib).

A simple style guide is instead: don't use these typedefs.

No manual actions, I only ran the bash script:

  FILES=($(git ls-files '*.[hc]'))
  sed -i \
      -e 's/\<g\(char\|short\|int\|long\|float\|double\)\>\( [^ ]\)/\1\2/g' \
      -e 's/\<g\(char\|short\|int\|long\|float\|double\)\>  /\1   /g' \
      -e 's/\<g\(char\|short\|int\|long\|float\|double\)\>/\1/g' \
      "${FILES[@]}"

Use the one from the project just imported.

NMAuthChain is not really ref-counted. True, we have an internal ref-counter
to ensure that the instance stays alive while the callback is invoked. However,
the user cannot take additional references as there is no nm_auth_chain_ref().

When the user wants to get rid of the auth-chain, with the current API it
is important that the callback won't be called after that point. From the
name nm_auth_chain_unref(), it sounds like that there could be multiple references
to the auth-chain, and merely unreferencing the object might not guarantee that
the callback is canceled. However, that is luckily not the case, because
there is no real ref-counting involved here.

Just rename the destroy function to make this clearer.

I dislike the static hash table to cache the integer counter for
numbered paths. Let's instead cache the counter at the class instance
itself -- since the class contains the information how the export
path should be exported.

However, we cannot use a plain integer field inside the class structure,
because the class is copied between derived classes. For example,
NMDeviceEthernet and NMDeviceBridge both get a copy of the NMDeviceClass
instance. Hence, the class doesn't contain the counter directly, but
a pointer to one counter that can be shared between sibling classes.

Previously, we used the generated GDBusInterfaceSkeleton types and glued
them via the NMExportedObject base class to our NM types. We also used
GDBusObjectManagerServer.

Don't do that anymore. The resulting code was more complicated despite (or
because?) using generated classes. It was hard to understand, complex, had
ordering-issues, and had a runtime and memory overhead.

This patch refactors this entirely and uses the lower layer API GDBusConnection
directly. It replaces the generated code, GDBusInterfaceSkeleton, and
GDBusObjectManagerServer. All this is now done by NMDbusObject and NMDBusManager
and static descriptor instances of type GDBusInterfaceInfo.

This adds a net plus of more then 1300 lines of hand written code. I claim
that this implementation is easier to understand. Note that previously we
also required extensive and complex glue code to bind our objects to the
generated skeleton objects. Instead, now glue our objects directly to
GDBusConnection. The result is more immediate and gets rid of layers of
code in between.
Now that the D-Bus glue us more under our control, we can address issus and
bottlenecks better, instead of adding code to bend the generated skeletons
to our needs.

Note that the current implementation now only supports one D-Bus connection.
That was effectively the case already, although there were places (and still are)
where the code pretends it could also support connections from a private socket.
We dropped private socket support mainly because it was unused, untested and
buggy, but also because GDBusObjectManagerServer could not export the same
objects on multiple connections. Now, it would be rather straight forward to
fix that and re-introduce ObjectManager on each private connection. But this
commit doesn't do that yet, and the new code intentionally supports only one
D-Bus connection.
Also, the D-Bus startup was simplified. There is no retry, either nm_dbus_manager_start()
succeeds, or it detects the initrd case. In the initrd case, bus manager never tries to
connect to D-Bus. Since the initrd scenario is not yet used/tested, this is good enough
for the moment. It could be easily extended later, for example with polling whether the
system bus appears (like was done previously). Also, restart of D-Bus daemon isn't
supported either -- just like before.

Note how NMDBusManager now implements the ObjectManager D-Bus interface
directly.

Also, this fixes race issues in the server, by no longer delaying
PropertiesChanged signals. NMExportedObject would collect changed
properties and send the signal out in idle_emit_properties_changed()
on idle. This messes up the ordering of change events w.r.t. other
signals and events on the bus. Note that not only NMExportedObject
messed up the ordering. Also the generated code would hook into
notify() and process change events in and idle handle, exhibiting the
same ordering issue too.
No longer do that. PropertiesChanged signals will be sent right away
by hooking into dispatch_properties_changed(). This means, changing
a property in quick succession will no longer be combined and is
guaranteed to emit signals for each individual state. Quite possibly
we emit now more PropertiesChanged signals then before.
However, we are now able to group a set of changes by using standard
g_object_freeze_notify()/g_object_thaw_notify(). We probably should
make more use of that.

Also, now that our signals are all handled in the right order, we
might find places where we still emit them in the wrong order. But that
is then due to the order in which our GObjects emit signals, not due
to an ill behavior of the D-Bus glue. Possibly we need to identify
such ordering issues and fix them.

Numbers (for contrib/rpm --without debug on x86_64):

- the patch changes the code size of NetworkManager by
  - 2809360 bytes
  + 2537528 bytes (-9.7%)

- Runtime measurements are harder because there is a large variance
  during testing. In other words, the numbers are not reproducible.
  Currently, the implementation performs no caching of GVariants at all,
  but it would be rather simple to add it, if that turns out to be
  useful.
  Anyway, without strong claim, it seems that the new form tends to
  perform slightly better. That would be no surprise.

  $ time (for i in {1..1000}; do nmcli >/dev/null || break; echo -n .;  done)
  - real    1m39.355s
  + real    1m37.432s

  $ time (for i in {1..2000}; do busctl call org.freedesktop.NetworkManager /org/freedesktop org.freedesktop.DBus.ObjectManager GetManagedObjects > /dev/null || break; echo -n .; done)
  - real    0m26.843s
  + real    0m25.281s

- Regarding RSS size, just looking at the processes in similar
  conditions, doesn't give a large difference. On my system they
  consume about 19MB RSS. It seems that the new version has a
  slightly smaller RSS size.
  - 19356 RSS
  + 18660 RSS

The next commit will completely rework NMBusManager and replace
NMExportedObject by a new type NMDBusObject.

Originally, NMDBusObject was added along NMExportedObject to ease
the rework and have compilable, intermediate stages of refactoring. Now,
I think the new name is better, because NMDBusObject is very strongly related
to the bus manager and the old name NMExportedObject didn't make that
clear.

I also slighly prefer the name NMDBusObject over NMBusObject, hence
for consistancy, also rename NMBusManager to NMDBusManager.

This commit only renames the file for a nicer diff in the next commit.
It does not actually update the type name in sources. That will be done
later.