After contract is migrated there is no way to retrieve it's state.
This commit implements some metadata for NEP5 contracts, so that
values important for diplaying transfer log aren't lost.
When synchronizing with stateroot-enabled network from genesis and if
stateroot is not enabled in block zero we were failing to update state height
because initially it's updated with a jump from 0 to StateRootEnableIndex, so
we should allow that to happen to have correct state height.
Fixes#1144. It's quite simple approach, we just update balance info right
upon contract migration. It will slow down migration transactions, but it
takes about 1-2 seconds to Seek through balances at mainnet's 3.8M, so the
approach should still work good enough. The other idea was to make lazy
updates (maintaining contract migration map), but it's more complicated to
implement (and implies that a balance get might also do a write).
There also is a concern about memory usage, it can give a spike of some tens
of megabytes, but that also is considered to be acceptable.
We need to compact our in-memory MPT from time to time, otherwise it quickly
fills up all available memory. This raises two obvious quesions --- when to do
that and to what level do that.
As for 'when', I think it's quite easy to use our regular persistence interval
as an anchor (and it also frees up some memory), but we can't do that in the
persistence routine itself because of synchronization issues (adding some
synchronization primitives would add some cost that I'd also like to avoid),
so do it indirectly by comparing persisted and current height in `storeBlock`.
Choosing proper level is another problem, but if we're to roughly estimate one
full branch node to use 1K of memory (usually it's way less than that) then we
can easily store 1K of these nodes and that gives us a depth of 10 for our
trie.
Items were serialized several times if there were several successful
transactions in a block, prevent that by using State field as a bitfield (as
it almost was intended to) and adding one more bit. It also eliminates useless
duplicate MPT traversions.
Confirmed to not break storage changes up to 3.3M on testnet.
This was differing from C# notion of PrevHash. It's not a previous root, but
rather a hash of the previous serialized MPTRoot structure (that is to be
signed by CNs).
Implement secp256k1 and secp256r1 recover interops, closes#1003.
Note:
We have to implement Koblitz-related math to recover keys properly
with Neo.Cryptography.Secp256k1Recover interop as far as standard
go elliptic package supports short-form Weierstrass curve with a=-3
only (see https://github.com/golang/go/issues/26776 for details).
However, it's not the best choise to have a lot of such math in our
project, so it would be better to use ready-made solution for
Koblitz-related cryptography.
Because trie size is rather big, it can't be stored in memory.
Thus some form of caching should also be implemented. To avoid
marshaling/unmarshaling of items which are close to root and are used
very frequenly we can save them across the persists.
This commit implements pruning items at the specified depth,
replacing them by hash nodes.
There is nothing wrong with iterators being implemented in other parts
of code (e.g. Storage.Find). In this case type assertions can
prevent bugs at compile-time.
Reproduce behavior of the reference realization:
- if item was Put in cache after it was encountered during
Storage.Find, it must appear twice
- checking if item is in cache must be performed in real-time
during `Iterator.Next()`
The order in which storage.Find items are returns depends on what items
were processed in previous transactions of the same block.
The easiest way to implement this sort of caching is to cache operations
with storage, flushing the only in `Persist()`.
This syscall should only work for contracts created by current transaction and
that is what is supposed to be checked here. Do so by looking at the
differences between ic.dao and original lower DAO.
Our block.Block was JSONized in a bit different fashion than result.Block in
its Nonce and NextConsensus fields. It's not good for notifications because
third-party clients would probably expect to see the same format. Also, using
completely different Block representation in result is probably making our
client a bit weaker as this representation is harder to use with other neo-go
components.
So use the same approach we took for Transactions and wrap block.Base which is
to be serialized in proper way.
