163 lines
4.0 KiB
Nim
163 lines
4.0 KiB
Nim
## Nim-Codex
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## Copyright (c) 2021 Status Research & Development GmbH
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## Licensed under either of
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## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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## * MIT license ([LICENSE-MIT](LICENSE-MIT))
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## at your option.
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## This file may not be copied, modified, or distributed except according to
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## those terms.
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import std/sequtils
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import pkg/upraises
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push: {.upraises: [].}
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import std/options
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import pkg/chronicles
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import pkg/chronos
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import pkg/libp2p
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import pkg/lrucache
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import pkg/questionable
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import pkg/questionable/results
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import ./blockstore
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import ../chunker
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import ../errors
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export blockstore
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logScope:
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topics = "codex cachestore"
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type
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CacheStore* = ref object of BlockStore
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currentSize*: Natural # in bytes
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size*: Positive # in bytes
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cache: LruCache[Cid, Block]
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InvalidBlockSize* = object of CodexError
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const
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MiB* = 1024 * 1024 # bytes, 1 mebibyte = 1,048,576 bytes
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DefaultCacheSizeMiB* = 5
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DefaultCacheSize* = DefaultCacheSizeMiB * MiB # bytes
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method getBlock*(self: CacheStore, cid: Cid): Future[?!Block] {.async.} =
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## Get a block from the stores
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##
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trace "Getting block from cache", cid
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if cid.isEmpty:
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trace "Empty block, ignoring"
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return success cid.emptyBlock
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if cid notin self.cache:
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return failure (ref BlockNotFoundError)(msg: "Block not in cache")
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try:
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return success self.cache[cid]
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except CatchableError as exc:
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trace "Error requesting block from cache", cid, error = exc.msg
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return failure exc
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method hasBlock*(self: CacheStore, cid: Cid): Future[?!bool] {.async.} =
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## Check if the block exists in the blockstore
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##
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trace "Checking CacheStore for block presence", cid
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if cid.isEmpty:
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trace "Empty block, ignoring"
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return true.success
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return (cid in self.cache).success
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method listBlocks*(s: CacheStore, onBlock: OnBlock): Future[?!void] {.async.} =
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## Get the list of blocks in the BlockStore. This is an intensive operation
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##
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for cid in toSeq(s.cache.keys):
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await onBlock(cid)
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return success()
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func putBlockSync(self: CacheStore, blk: Block): bool =
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let blkSize = blk.data.len # in bytes
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if blkSize > self.size:
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trace "Block size is larger than cache size", blk = blkSize, cache = self.size
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return false
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while self.currentSize + blkSize > self.size:
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try:
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let removed = self.cache.removeLru()
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self.currentSize -= removed.data.len
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except EmptyLruCacheError as exc:
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# if the cache is empty, can't remove anything, so break and add item
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# to the cache
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trace "Exception puting block to cache", exc = exc.msg
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break
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self.cache[blk.cid] = blk
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self.currentSize += blkSize
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return true
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method putBlock*(self: CacheStore, blk: Block): Future[?!void] {.async.} =
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## Put a block to the blockstore
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##
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trace "Storing block in cache", cid = blk.cid
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if blk.isEmpty:
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trace "Empty block, ignoring"
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return success()
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discard self.putBlockSync(blk)
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return success()
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method delBlock*(self: CacheStore, cid: Cid): Future[?!void] {.async.} =
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## Delete a block from the blockstore
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##
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trace "Deleting block from cache", cid
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if cid.isEmpty:
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trace "Empty block, ignoring"
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return success()
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let removed = self.cache.del(cid)
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if removed.isSome:
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self.currentSize -= removed.get.data.len
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return success()
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method close*(self: CacheStore): Future[void] {.async.} =
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## Close the blockstore, a no-op for this implementation
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##
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discard
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func new*(
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_: type CacheStore,
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blocks: openArray[Block] = [],
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cacheSize: Positive = DefaultCacheSize, # in bytes
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chunkSize: Positive = DefaultChunkSize # in bytes
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): CacheStore {.raises: [Defect, ValueError].} =
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if cacheSize < chunkSize:
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raise newException(ValueError, "cacheSize cannot be less than chunkSize")
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var currentSize = 0
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let
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size = cacheSize div chunkSize
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cache = newLruCache[Cid, Block](size)
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store = CacheStore(
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cache: cache,
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currentSize: currentSize,
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size: cacheSize)
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for blk in blocks:
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discard store.putBlockSync(blk)
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return store
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