nim-codex/dagger/storestream.nim

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2022-03-16 21:48:10 +00:00
## Nim-Dagger
## Copyright (c) 2022 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.
{.push raises: [Defect].}
import pkg/libp2p
import pkg/chronos
import pkg/chronicles
import pkg/stew/ptrops
import ./stores
import ./manifest
import ./blocktype
export stores
logScope:
topics = "dagger storestream"
type
ReadPattern* {.pure.} = enum
Sequential,
Grid
StoreStream* = ref object of LPStream
store*: BlockStore
manifest*: Manifest
pattern*: ReadPattern
offset*: int
proc init*(
T: type StoreStream,
store: BlockStore,
manifest: Manifest,
pattern = ReadPattern.Sequential): T =
result = T(
store: store,
manifest: manifest,
pattern: pattern,
offset: 0)
result.initStream()
method readOnce*(
self: StoreStream,
pbytes: pointer,
nbytes: int): Future[int] {.async.} =
if self.atEof:
raise newLPStreamEOFError()
var
read = 0
while read < nbytes and self.atEof.not:
let
pos = self.offset div self.manifest.blockSize
let
blk = (await self.store.getBlock(self.manifest[pos])).tryGet()
blockOffset = if self.offset >= self.manifest.blockSize:
self.offset mod self.manifest.blockSize
else:
self.offset
readBytes = if (nbytes - read) >= (self.manifest.blockSize - blockOffset):
self.manifest.blockSize - blockOffset
else:
min(nbytes - read, self.manifest.blockSize)
copyMem(pbytes.offset(read), unsafeAddr blk.data[blockOffset], readBytes)
self.offset += readBytes
read += readBytes
return read
method atEof*(self: StoreStream): bool =
self.offset >= self.manifest.len * self.manifest.blockSize
method closeImpl*(self: StoreStream) {.async.} =
try:
trace "Closing StoreStream", self
self.offset = self.manifest.len * self.manifest.blockSize # set Eof
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "Error closing StoreStream", s, msg = exc.msg
await procCall LPStream(self).closeImpl()