This commit is a rather large one which implements transaction pool and
relay according to the protocol rules of the reference implementation.
It makes use of btcchain to ensure the transactions are valid for the
block chain and includes several stricter checks which determine if they
are "standard" or not before admitting them into the pool and relaying
them.
There are still a few TODOs around the more strict rules which determine
which transactions are willing to be mined, but the core checks which
are imperative (everything except the all of the "standard" checks really)
to operate as a good citizen on the bitcoin network are in place.
FetchTxBySha changes what it returns, it can now return a TxListReply and
and error if none are found.
FetchTxByShaList is renamed to FetchUnSpentTxByShaList to indicate that
it will (likey/eventually) only return Tx that have some unspent TxOuts.
Tx which are fully spent may not be (reliably) looked up using this API.
We originally wanted to also not fetch orphan parents in this commit, however,
I have discovered that if you are doing a main sync from a peer, if it
sends you an orphan you must fetch it, else you ahven't fetched
everything it told you about and thus it will nto send you end more invs
from the main sync.
So we always fetch orphan parents, but we still don't fetch from
non-sync peers (all invs from them will be unsolicited). Seems to fix some hangs
with multiple peers.
The "official" regression test tool intentionally sends some unrequested
duplicate blocks to ensure the chain handling code does not fail when
trying to insert them. This commit adds an exception to the block manager
which typically disconnects peers that send unrequested blocks (they are
misbehaving if they do this) for regression test mode.
Really, it would be nice to pass an interface{} into chain to be given
to us when the callback calls, it would avoid the awkward sidchanneling
through the map and should actually be more efffieint (pointer passing >
hashtable insert, lookup, then remove).
Rather than using a channel for notifictions, use a callback instead.
There are several issues that arise with async notifications via a
channel, so use a callback instead. The caller can always make the
notifications async by using channels in the provided callback if
needed.
Rather than having all of the various places that print peer figure out
the direction and form the string, centralize it by implementing the
Stringer interface on the peer.
Chain is not concurrency safe, so we move the chainNotifySink handling
into the main blockmanager goroutine. Due to a possible deadlock if the
buffer is filled this still has to be a single channel that isn't linked
to the other ones. There is a possible starvation issue where the main
msgChan gets selected more often than the notification sink, but until
chain is concurrency safe this is rather unavoidable.
Only log errors for most cases if the peer is persisent (and thus requested).
Only log by default after version exchange, and after losing a peer that had
completed version exchange. Make most other messages debug.
This commit modifies CheckInputTransactions to ensure that not only must a
transaction exist in the transaction store, it must also not have any
errors associated with it or be nil.
We would occasionally hang or a while during server shudown, this is due
to an outbound peer waiting on a connection or a sleep. However, we
don't actually require to wait for the peers to finish at all. So just
let them finish.
Secondly, make peer.disconnnect and server.shutdown atomic varaibles so
that checking them from multiple goroutines isn't race, and clean up
their usage.
