nimbus-eth1/nimbus/p2p/validate/epoch_hash_cache.nim

67 lines
2.1 KiB
Nim

# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except
# according to those terms.
## Hash Cache
## ==========
##
## provide LRU hash, indexed by epoch
import
../../utils/lru_cache,
ethash,
nimcrypto,
tables
type
BlockEpoch = distinct uint64
EpochHashDigest* = seq[MDigest[512]]
EpochHashCache* = LruCache[uint64,BlockEpoch,EpochHashDigest,void]
{.push raises: [Defect,CatchableError].}
# ------------------------------------------------------------------------------
# Private cache management functions
# ------------------------------------------------------------------------------
# needed for table key to work
proc `==`(a,b: BlockEpoch): bool {.borrow.}
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc initEpochHashCache*(cache: var EpochHashCache; cacheMaxItems = 10) =
## Initialise a new cache indexed by block epoch
template bnToEpoch(num: uint64): BlockEpoch =
BlockEpoch(blockNumber div EPOCH_LENGTH)
var toKey: LruKey[uint64,BlockEpoch] =
proc(blockNumber: uint64): BlockEpoch =
blockNumber.bnToEpoch
var toValue: LruValue[uint64,EpochHashDigest,void] =
proc(blockNumber: uint64): Result[EpochHashDigest,void] =
let top = blockNumber.bnToEpoch.uint64 * EPOCH_LENGTH
ok( mkcache( getCacheSize(top), getSeedhash(top)))
cache.initCache(toKey, toValue, cacheMaxItems)
proc getEpochHash*(cache: var EpochHashCache;
blockNumber: uint64): auto {.inline.} =
## Return hash list, indexed by epoch of argument `blockNumber`
cache.getItem(blockNumber).value
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------