Tuesdays idea of adding some code into the SyncSPVAction didn't feel
right.
A second look made clear that bloom filter updates make much more sense
to go hand in hand with sending a mempool message. Especially since they
depend on each other on the server side.
To-rehash:
the wallet may decide at any time that a new bloom filter is needed. It
then uses the superclass (code in p2plib) PrivacySegment, to build that
filter. As part of that we get a lock object which, when going out of
scope, makes the peers that are subscribed to the privacySegment send
out the filter.
This separation of concerns means that the subclass wallet in the app
doens't know about peers or messages, only its superclass PrivacySegment
does.
What we did in this change is make the PrivacySegment class decide to
combine a bloom update with a mempool call. Typicall only once per
connection.
This means I can remove hacks in the SyncSPVAction which forced the
sending of the mempool message separately.
The job description of this component is to sync a wallet. Its means to
that end is to connect to peers.
Problem is that when we startup and the whole system is already in-sync,
then we forget to connect to peers. (that wasn't in the job description,
it just happened to be done as a sideeffect).
This changes the SyncSPVAction's job description to also make sure that
each wallet has the required number of peers.
We send a 'mempool' p2p command to a peer after we did a series of
merkleblock downloads.
This code adds the mempool p2p command to be sent to peers that didn't
participate in the merkleblock download and thus get the best out of all
our connected peers.
This is done in several steps:
1. Separate my height from the remote peer heights.
Instead of assuming we have one height, recognize that a peer may
not be at the tip at the same time we are. We monitor headers/invs
to update the 'peerHeight' variable.
2. Ask for merkle blocks from a peer to the maximum height of that
peer (but not later than what we validated to be true).
This avoids us asking past the remotes tip which they didn't like.
3. Redo the SyncSPVAction to use all this and make it much more
reliable in finding peers to download from and getting all the
changes as fast as possible.
We connect to the "first" priority stated segments first, in order to
allow the UX to be made much better since it may take a bit of time to
find peers.
We reuse the NetworkManager lower level code in order to connect
to the Bitcoin P2P network.
This implements the basics for anyone wanting to be a player on
this network.
tomFlowee
TomZ