Follow missed change from neo-project/neo#1816 .
`None` may be used for any signer. Currently it is used
for sender to only pay fees, or to sign tx attributes.
First PUSHDATA1 is from invocation script, the second PUSHDATA1 is
from verification script. E.g.:
Invocation script:
INDEX OPCODE PARAMETER
0 PUSHDATA1 035913b9588da23a5c3ce14b2886a6b8ebb6a0eb92bdaa948510dfb5ae5194d6cb <<
35 PUSHNULL
36 SYSCALL Neo.Crypto.VerifyWithECDsaSecp256r1 (95440d78)
Verification script:
INDEX OPCODE PARAMETER
0 PUSHDATA1 3930fe5a9b44682f37741955df4a5f2585ed5aa438fa6e17ae51083673b1d64253e5a859c0cf168be67971e53a23c1c40582777d94a8e391db23ff613849627d <<
Now we have VerifyTx() and PoolTx() APIs that either verify transaction in
isolation or verify it against the mempool (either the primary one or the one
given) and then add it there. There is no possibility to check against the
mempool, but not add a transaction to it, but I doubt we really need it.
It allows to remove some duplication between old PoolTx and verifyTx where
they both tried to check transaction against mempool (verifying first and then
adding it). It also saves us utility token balance check because it's done by
the mempool anyway and we no longer need to do that explicitly in verifyTx.
It makes AddBlock() and verifyBlock() transaction's checks more correct,
because previously they could miss that even though sender S has enough
balance to pay for A, B or C, he can't pay for all of them.
Caveats:
* consensus is running concurrently to other processes, so things could
change while verifyBlock() is iterating over transactions, this will be
mitigated in subsequent commits
Improves TPS value for single node by at least 11%.
Fixes#667, fixes#668.
New transactions are added to the chain with blocks. If there is no
transaction X at height N in DAO, it could only be added with block N+1, so
it has to be present there. Therefore we can replace `dao.HasTransaction()`
check with a search through in-block transactions. HasTransaction() is nasty
in that it may add useless load the DB and this code is being run with a big
Blockchain lock held, so we don't want to be delayed here at all.
Improves single-node TPS by ~2%.
The end effect is almost as if `VerifyTransactions: false` was set in the
config, but without actually compromising the guarantees provided by it.
It almost doubles performance for single-mode benchmarks and makes block
processing smoother (more smaller blocks are being produced).
