Follow neo-project/neo#2807. Notice that this data is not cached, our previous
implementation wasn't too and it shouldn't be a problem (not on the hot path).
Blockchain's subscriptions, unsubscriptions and notifications are
handled by a single notificationDispatcher routine. Thus, on attempt
to send the subsequent event to Blockchain's subscribers, dispatcher
can't handle subscriptions\unsubscriptions. Make subscription and
unsubscription to be a non-blocking operation for blockchain on the
server side, otherwise it may cause the dispatcher locks.
To achieve this, use a separate lock for those code that make calls
to blockchain's subscription API and for subscription counters on
the server side.
If VUB-th block is received, we still can't guaranty that transaction
wasn't accepted to chain. Back this situation by rolling back to a
poll-based waiter.
Do not block subscribers until the unsubscription request to RPC server
is completed. Otherwise, another notification may be received from the
RPC server which will block the unsubscription process.
At the same time, fix event-based waiter. We must not block the receiver
channel during unsubscription because there's a chance that subsequent
event will be sent by the server. We need to read this event in order not
to block the WSClient's readloop.
client_test.go:1935:
Error Trace: /home/rik/dev/neo-go/pkg/services/rpcsrv/client_test.go:1935
Error: Should NOT be empty, but was 00000000-0000-0000-0000-000000000000
Test: TestClient_Iterator_SessionConfigVariations/sessions_disabled
It's obviously empty, since we have sessions disabled, but it was not
considered to be empty in testify 1.7.0, now it is, see 840cb80149
NEP-6 has a notion of locked acccounts and SignTx must respect this user's
choice. For some reason this setting was inappropriately used by our RPC
client tests (probably a different kind of lock was meant).
calculatenetworkfee MUST calculate complete proper network fee, if we have
some extensions enabled and some attributes should be paid for that they're a
part of the equation too.
We're dealing with a transaction here and it can't be decoded successfully
unless it has an appropriate number of witness scripts (matching the number of
signers) with appropriate hashes (matching signers). So this iterations make
no sense at all, we know exactly where to look for the
verification/invocation scripts.
Blockchain's notificationDispatcher sends events to channels and these
channels must be read from. Unfortunately, regular service shutdown procedure
does unsubscription first (outside of the read loop) and only then drains the
channel. While it waits for unsubscription request to be accepted
notificationDispatcher can try pushing more data into the same channel which
will lead to a deadlock. Reading in the same method solves this, any number of
events can be pushed until unsub channel accepts the data.
Unfortunately Go doesn't allow to easily reuse readers in full packages, still
we can have this wrapper with a little overhead (the alternative is to move
specific methods into types of their own, but I'm not sure how it's going to
be accepted user-side).
Notice that int64 types are used for gas per block or registration price
because the price has to fit into the system fee limitation and gas per block
value can't be more than 10 GAS. We use int64 for votes as well in other types
since NEO is limited to 100M.
