Task #3088
Updated by Junxiao Shi about 9 years ago
Refactor `Face` to support [[NDNLPv2]] link service and permanent faces.
High-level design: <https://gist.github.com/yoursunny/22a7d53711b4e9bc198a>
This issue implements:
* `LinkService` and `Transport` base classes
* minimal `GenericLinkService` that only does Interest/Data/Nack \<=\> LpPacket encoding and decoding
* non-inheritable `Face` class that combines a `LinkService` and a `Transport`;
to avoid conflicts with old `nfd::Face`, this class is temporarily named `LpFace`
* `sendNack` method and `onReceiveNack` signal on old `nfd::Face`, so that forwarding can use them;
in `nfd::Face` base class, these do nothing
* `LpFaceWrapper` class which is an adapter that inherits from old `nfd::Face` but wraps an `LpFace`
This is an initial step toward a Face that supports [[NDNLPv2]] and full-featured permanent face.