nim-codex/codex/stores/cachestore.nim

96 lines
2.3 KiB
Nim

## Nim-Codex
## Copyright (c) 2021 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import pkg/upraises
push: {.upraises: [].}
import std/options
import pkg/chronicles
import pkg/chronos
import pkg/libp2p
import pkg/lrucache
import pkg/questionable
import pkg/questionable/results
import ./blockstore
import ../chunker
import ../errors
import ../manifest
export blockstore
logScope:
topics = "codex cachestore"
type
CacheStore* = ref object of BlockStore
backingStore: BlockStore
cache: LruCache[Cid, Block]
const
MiB* = 1024 * 1024
DefaultCacheSizeMiB* = 5
DefaultCacheSize* = DefaultCacheSizeMiB * MiB
method getBlock*(self: CacheStore, cid: Cid): Future[?!Block] {.async.} =
if cid.isEmpty:
trace "Empty block, ignoring"
return success(cid.emptyBlock)
if cid notin self.cache:
without blk =? await self.backingStore.getBlock(cid), err:
return failure(err)
self.cache[blk.cid] = blk
return success(blk)
trace "Returning block from cache"
return success self.cache[cid]
method hasBlock*(self: CacheStore, cid: Cid): Future[?!bool] =
self.backingStore.hasBlock(cid)
method listBlocks*(
self: CacheStore,
blockType = BlockType.Manifest): Future[?!BlocksIter] =
self.backingStore.listBlocks(blockType)
method putBlock*(
self: CacheStore,
blk: Block,
ttl = Duration.none): Future[?!void] =
self.backingStore.putBlock(blk, ttl)
method delBlock*(self: CacheStore, cid: Cid): Future[?!void] =
discard self.cache.del(cid)
self.backingStore.delBlock(cid)
method close*(self: CacheStore): Future[void] =
self.backingStore.close()
func new*(
_: type CacheStore,
backingStore: BlockStore,
cacheSize: Positive = DefaultCacheSize, # in bytes
chunkSize: Positive = DefaultChunkSize # in bytes
): CacheStore {.raises: [Defect, ValueError].} =
if cacheSize < chunkSize:
raise newException(ValueError, "cacheSize cannot be less than chunkSize")
let
size = cacheSize div chunkSize
cache = newLruCache[Cid, Block](size)
store = CacheStore(
backingStore: backingStore,
cache: cache)
return store