nimbus-eth1/nimbus/db/backends/caching_backend.nim

45 lines
1.1 KiB
Nim

import ranges, eth_trie, tables, sets
import ../storage_types
type
CachingDB* = ref object of RootObj
backing: TrieDatabaseRef
changed: Table[seq[byte], seq[byte]]
deleted: HashSet[seq[byte]]
proc newCachingDB*(backing: TrieDatabaseRef): CachingDB =
result.new()
result.backing = backing
result.changed = initTable[seq[byte], seq[byte]]()
result.deleted = initSet[seq[byte]]()
proc get*(db: CachingDB, key: openarray[byte]): seq[byte] =
let key = @key
result = db.changed.getOrDefault(key)
if result.len == 0 and key notin db.deleted:
result = db.backing.get(key)
proc put*(db: CachingDB, key, value: openarray[byte]) =
let key = @key
db.deleted.excl(key)
db.changed[key] = @value
proc contains*(db: CachingDB, key: openarray[byte]): bool =
let key = @key
result = key in db.changed
if not result and key notin db.deleted:
result = db.backing.contains(key)
proc del*(db: CachingDB, key: openarray[byte]) =
let key = @key
db.changed.del(key)
db.deleted.incl(key)
proc commit*(db: CachingDB) =
for k in db.deleted:
db.backing.del(k)
for k, v in db.changed:
db.backing.put(k, v)