NEO VM does not distinguish between empty and nil slices. Supporting
this is not easy and requires changing lots of other opcodes.
Pointers are not supported anyway and slices can be checked for
emptiness by inspecting their `len`.
Set default value also for complex (struct, map) types.
Note: because VM does not distinguish empty array and nil array,
comparison 'a == nil' can't be handled properly without substantial
effort. This will be fixed in NEO3.
Using view number from the recovery message is just plain wrong, it's gonna be
higher than our current view and these messages will be treated as coming from
the future, even though they have their original view number included.
Implement (*Param).GetBoolean() for converting parameter to bool value.
It is used for verbosity flag and is false iff it is either zero number
or empty sting.
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.
