Depending on the get_type argument, we don't only want
to return strings, but arbitrary pointers.
The out_to_free argument still makes sense, but depending on
the get-type you must know how to free the pointer.
When generating output data, nmcli iterates over a list of
property-descriptors (nmc_fields_ip4_config), creates an intermediate
array (output_data) and finally prints it.
However, previously both the meta data (nmc_fields_ip4_config) and
the intermediate format use the same type NmcOutputField. This means,
certain fields are relevant to describe a property, and other fields
are output/formatting fields.
Split this up. Now, the meta data is tracked in form of an NMMetaAbstractInfo
lists. This separates the information about properties from intermediate steps
during creation of the output.
Note that currently functions like print_ip4_config() still have all the
knowledge about how to generate the output. That is wrong, instead, the
meta data (NMMetaAbstractInfo) should describe how to create the output
and then all those functions could be replaced. This means, later we want
to add more knowledge to the NMMetaAbstractInfo, so it is important to
keep them separate from NmcOutputField.
Embed a @meta_type structure in NMMetaSettingInfoEditor and
NMMetaPropertyInfo. This allows to make the NMMeta*Info instances
themself to become generic and they can be passed around as generic
NMMetaAbstractInfo types.
For one, the embedded NMMetaType pointer can be used to determine
of which type a NMMetaAbstractInfo instance is. On the other hand,
the NMMetaType struct can be extended to be a VTable to provide
generic access to the type.
In the end, both NMMetaSettingInfoEditor and NMMetaPropertyInfo are
conceptionally very similar: the describe a certain type and provide
accessors.
In nmcli we have yet another NMMetaAbstractInfo type: NmcOutputField
will be modified to become another implementation of meta data (it
already is, it just cannot be used interchangable with the other
types).
Also, embed the NMMetaSettingInfoEditor in the NMMetaPropertyInfo
instance. This allows from a given NMMetaPropertyInfo to retrieve it's
parent NMMetaSettingInfoEditor.
The lower layers are concerned with handling settings. They should not
be aware of how to notify about warnings. Instead, signal them via
the warn_fcn() hook.
These functions are only used by nm-meta-setting-desc.c. Make them internal.
Unfortunately, they are part of "common.h" which cannot be used without
the rest of nmcli. Still todo.
This part contains static functions and variables to describe
settings. It is distinct from the mechanism to use them, or
access them.
Split it out.
It still uses clients/cli/common.h and clients/cli/utils.h
which shall be fixed next.
