Summary:
CMerkleBlock::CMerkleBlock called IsRelevantAndUpdate() on each transaction
in order, which (due to the outpoint-adding feature) assumes a topological
order of transactions in order to work correctly. If an outpoint of
interest were created later in a block than when gets spent, then it would
be added into the bloom filter too late, and thus that spending transaction
would get missed.
This changes CMerkleBlock::CMerkleBlock to scan all outputs first, then
make a second loop to scan all inputs. This requires breaking up the
IsRelevantAndUpdate() function into two parts. The original
IsRelevantAndUpdate() functionality remains fully intact however, as it
gets called from mempool-related code (mempool has topological order) and
tests.
Note that vMatchedTxn.push_back is moved into the second loop so that index
i keeps ascending order, in case that is somehow relevant. (the tests at
least do check this)
A two-loop construction like this will very slightly increase the false
positive rate.
Originally by: Mark Lundeberg
The API throws when the directories already exist, which is quite
unexpected.
This now changes the code to silently ignore these issues in the
knowledge that the immediately following opening of files will
fail with a nice error message.
This adds a unit test to see if the combination of invalidateBlock and
reconsiderBlock do what we expect to do.
The main issue was that we store an invalidated block in the UTXO and we
forgot to re-validate that on reconsider.
Additionally I avoid writing a lot of unchanged data to the block-index.
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 already had in place the blockSizeAcceptLimit as the limit
on messages, which is now the only limit.
In practice this means when the operator sets the maximum mining
size that we adjust the blockSizeAcceptLimit, if they only set the
blockSizeAcceptLimit, we use that (plus a margin) to limit messages
both on the p2p layer and on the RPC (JSON) layer we change the
limit to be twice the blockSizeAcceptLimit (copied those numbers
from BCHN).
In most cases headers would be automatically downloaded if we didn't
connect to that peer for a while, but that is not a guarentee so lets
make sure we actually start downloading headers from any peer we can :)
tomFlowee
TomZ