nimbus-eth1/fluffy/network/state/content.nim

114 lines
3.6 KiB
Nim

# Nimbus
# Copyright (c) 2021 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
# https://github.com/ethereum/stateless-ethereum-specs/blob/master/state-network.md#content
{.push raises: [Defect].}
import
std/[options, sugar],
nimcrypto/[sha2, hash], stew/objects, stint,
eth/ssz/ssz_serialization, eth/trie/[hexary, db]
export ssz_serialization
type
ByteList* = List[byte, 2048]
ContentType* = enum
Account = 0x01
ContractStorage = 0x02
ContractBytecode = 0x03
NetworkId* = uint16
NodeHash* = MDigest[32 * 8] # keccak256
CodeHash* = MDigest[32 * 8] # keccak256
Address* = array[20, byte]
ContentKey* = object
networkId*: NetworkId
contentType*: ContentType
# TODO: How shall we deal with the different ContentKey structures?
# Lets start with just node hashes for now.
# address: Address
# triePath: ByteList
nodeHash*: NodeHash
ContentId* = MDigest[32 * 8]
KeccakHash* = MDigest[32 * 8] # could also import from either eth common types or trie defs
template toSszType*(x: ContentType): uint8 =
uint8(x)
template toSszType*(x: auto): auto =
x
func fromSszBytes*(T: type ContentType, data: openArray[byte]):
T {.raises: [MalformedSszError, Defect].} =
if data.len != sizeof(uint8):
raiseIncorrectSize T
var contentType: T
if not checkedEnumAssign(contentType, data[0]):
raiseIncorrectSize T
contentType
func encodeKey*(contentKey: ContentKey): seq[byte] =
SSZ.encode(contentKey)
# TODO consider if more powerfull error handling is necessary here.
func decodeKey*(contentKey: ByteList): Option[ContentKey] =
try:
some(SSZ.decode(contentKey.asSeq(), ContentKey))
except SszError:
return none[ContentKey]()
func encodeKeyAsList*(contentKey: ContentKey): ByteList =
List.init(encodeKey(contentKey), 2048)
func toContentId*(contentKey: ByteList): ContentId =
# TODO: Hash function to be defined, sha256 used now, might be confusing
# with keccak256 that is used for the actual nodes:
# https://github.com/ethereum/stateless-ethereum-specs/blob/master/state-network.md#content
sha2.sha_256.digest(contentKey.asSeq())
func toContentId*(contentKey: ContentKey): ContentId =
toContentId(encodeKeyAsList(contentKey))
func contentIdAsUint256*(id: ContentId): Uint256 =
readUintBE[256](id.data)
type
ContentStorage* = object
# TODO: Quick implementation for now where we just use HexaryTrie, current
# idea is to move in here a more direct storage of the trie nodes, but have
# an `ContentProvider` "interface" that could provide the trie nodes via
# this direct storage, via the HexaryTrie (for full nodes), or also without
# storage, via json rpc client requesting data from a full eth1 client.
trie*: HexaryTrie
proc getContent*(storage: ContentStorage, key: ContentKey): Option[seq[byte]] =
if storage.trie.db == nil: # TODO: for now...
return none(seq[byte])
let val = storage.trie.db.get(key.nodeHash.data)
if val.len > 0:
some(val)
else:
none(seq[byte])
proc getContent*(storage: ContentStorage, contentKey: ByteList): Option[seq[byte]] =
decodeKey(contentKey).flatMap((key: ContentKey) => getContent(storage, key))
proc newEmptyInMemoryStorage*(): ContentStorage =
let trie = initHexaryTrie(newMemoryDb())
ContentStorage(trie: trie)