NMSetting instances either have no private data, they use
g_type_add_class_private(), or they embed the private data in the
NMSetting struct.
In all cases, we can find the private data at a fixed offset. Track that
offset in the NMSettInfoSetting meta data.
This will be useful, because properties really are stored in simple
fields, like a boolean property can be stored in a "bool" field. We will
extend the property meta data to track the offset of this property
field, but we also need to know where the offset starts.
Most of our NMSetting properties are based around GObject properties,
and thus the tooling to convert a NMSetting to/from GVariant consists
of getting/setting a GValue.
We can do better.
For most of such properties we also define a C getter function, which
we can call with less overhead. All we need is to hook the C getter with
the property meta data.
As example, implement it for "connection.autoconnect".
The immediate goal of this is to reduce the overhead of to_dbus. But
note that also for comparison of two properties, there is the default
implementation which is used by the majority of properties. This
implementation converts the properties first to GVariant (via
to_dbus_fcn) and then compares the variants. What this commit also does,
is to hook up the property meta data with the C-getters. This is one step
towards also more efficiently compare properties using the naive C
getters. Likewise, the keyfile writer use g_object_get_property().
It also could do better.
For each property we have meta data in form of NMSettInfoProperty.
Each meta data also has a NMSettInfoProperty.property_type
(NMSettInfoPropertType).
The property type is supposed to define common behaviors for properties,
while the property meta data has individual properties. The idea is that
several properties can share the same property-type, and that
per-property meta data is part of NMSettInfoProperty.
The distinction is not very strong, but note that all remaining uses
of NMSettInfoPropertType.gprop_to_dbus_fcn were part of a property
type that was only used for one single property. That lack of
reusability hints to a wrong use.
Move gprop_to_dbus_fcn to the property meta data as a new field
NMSettInfoProperty.to_dbus_data.
Note that NMSettInfoPropertType.gprop_from_dbus_fcn still suffers from
the same problem. But the from-dbus side is not yet addressed.
The advantage is that we use similar macros for initializing the
static structs like
const NMSettInfoPropertType nm_sett_info_propert_type_cloned_mac_address;
and the ad-hoc locations that use NM_SETT_INFO_PROPERT_TYPE().
The former exist for property types that are used more than once.
The latter exist for convenience, where a property type is implemented
at only one place.
Also, there are few direct references to _nm_setting_property_to_dbus_fcn_gprop().
all users use NM_SETT_INFO_PROPERT_TYPE_GPROP() or
NM_SETT_INFO_PROPERT_TYPE_GPROP_INIT().
If a property can be converted to D-Bus, then always set the
to_dbus_fcn() handler. The only caller of to_dbus_fcn() is
property_to_dbus(), so this means that property_to_dbus()
has no more default implementation and always delegates to
to_dbus_fcn().
The code is easier to understand if all properties implement
to_dbus_fcn() the same way.
Also, there is supposed to be a split between NMSettInfoProperty (info about
the property) and NMSettInfoPropertType (the type). The idea is that
each property (obviously) requires its distinct NMSettInfoProperty, but
they can share a common type implementation.
With NMSettInfoPropertType.gprop_to_dbus_fcn that is often violated because
many properties that implement NMSettInfoPropertType.gprop_to_dbus_fcn
require a special type implementation. As such, gprop_to_dbus_fcn should
be part of the property info and not the property type. The first step towards
that is unifying all properties to use to_dbus_fcn().
The buffer created here is only temporary to construct the property info
by _nm_setting_class_commit_full(). We can afford to allocate more than
necessary, if we thereby avoid several reallocations.
NMConnection is a glib interface, implemented only by NMSimpleConnection
and NMRemoteConnection.
Inside the daemon, every NMConnection instance is always a NMSimpleConnection.
Using glib interfaces has an overhead, for example NM_IS_CONNECTION() needs
to search the implemented types for the pointer. And NM_CONNECTION_GET_PRIVATE()
is implemented by attaching user data to the GObject instance. Both have measurable
overhead.
Special case them for NMSimpleConnection.
This optimizes primarily the call to nm_connection_get_setting_connection(),
which easily gets called millions of times. This is easily measurable.
When subclassing a GObject type, the class and object structs
must be available and defined in the header.
For libnm, and in particular for NMSetting classes, we don't want
users to subclass NMSetting. It also doesn't work, because libnm
has internal code that is necessary to hook up the NMSetting class.
You cannot define your own type and make it work together with
libnm.
Having the structs in public headers limits what we can do with them.
For example, we could embed the private data directly in the structures
and avoid the additional indirection.
This is an API break, but for something that most likely nobody cares
about. Or better, nobody should care about. API is not what is
accidentally defined in a header, API was the library provides to
meaningfully use. Subclassing these types is not meaningful and was
only accidentally possible so far.
Only hide the structs for now. More cleanup is possible later. We shall
however aim to keep the padding and struct layout to not also break ABI.
(cherry picked from commit e46d484fae)
"libnm-core/" is rather complicated. It provides a static library that
is linked into libnm.so and NetworkManager. It also contains public
headers (like "nm-setting.h") which are part of public libnm API.
Then we have helper libraries ("libnm-core/nm-libnm-core-*/") which
only rely on public API of libnm-core, but are themself static
libraries that can be used by anybody who uses libnm-core. And
"libnm-core/nm-libnm-core-intern" is used by libnm-core itself.
Move "libnm-core/" to "src/". But also split it in different
directories so that they have a clearer purpose.
The goal is to have a flat directory hierarchy. The "src/libnm-core*/"
directories correspond to the different modules (static libraries and set
of headers that we have). We have different kinds of such modules because
of how we combine various code together. The directory layout now reflects
this.
2021-02-18 19:46:51 +01:00
Renamed from libnm-core/nm-setting-private.h (Browse further)
