nim-codex/dagger/streams/storestream.nim

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## 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.
import pkg/upraises
push: {.upraises: [].}
import pkg/libp2p
import pkg/chronos
import pkg/chronicles
import pkg/stew/ptrops
import ../stores
import ../manifest
import ../blocktype
import ./seekablestream
export stores, blocktype, manifest, chronos
logScope:
topics = "dagger storestream"
type
StoreStream* = ref object of SeekableStream
store*: BlockStore
manifest*: Manifest
proc new*(
T: type StoreStream,
store: BlockStore,
manifest: Manifest): T =
result = T(
store: store,
manifest: manifest,
offset: 0)
result.initStream()
method size*(self: StoreStream): int =
self.manifest.len * self.manifest.blockSize
method readOnce*(
self: StoreStream,
pbytes: pointer,
nbytes: int): Future[int] {.async.} =
if self.atEof:
raise newLPStreamEOFError()
var
read = 0
while read < nbytes and not self.atEof:
let
pos = self.offset div self.manifest.blockSize
blk = (await self.store.getBlock(self.manifest[pos])).tryGet()
let
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.offset = self.manifest.len * self.manifest.blockSize # set Eof
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "Error closing StoreStream", msg = exc.msg
await procCall LPStream(self).closeImpl()