135 lines
3.2 KiB
Nim
135 lines
3.2 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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# TODO: This is super inneficient and needs a rewrite, but it'll do for now
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import pkg/upraises
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push: {.upraises: [].}
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import pkg/chronicles
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import pkg/questionable
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import pkg/questionable/results
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import pkg/chronos
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import pkg/libp2p except shuffle
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import ./blocktype
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export blocktype
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const
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DefaultChunkSize* = BlockSize
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type
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# default reader type
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ChunkBuffer* = ptr UncheckedArray[byte]
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Reader* = proc(data: ChunkBuffer, len: int): Future[int] {.gcsafe, raises: [Defect].}
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# Reader that splits input data into fixed-size chunks
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Chunker* = ref object
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reader*: Reader # Procedure called to actually read the data
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offset*: int # Bytes read so far (position in the stream)
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chunkSize*: Natural # Size of each chunk
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pad*: bool # Pad last chunk to chunkSize?
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FileChunker* = Chunker
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LPStreamChunker* = Chunker
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proc getBytes*(c: Chunker): Future[seq[byte]] {.async.} =
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## returns a chunk of bytes from
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## the instantiated chunker
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##
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var buff = newSeq[byte](c.chunkSize)
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let read = await c.reader(cast[ChunkBuffer](addr buff[0]), buff.len)
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if read <= 0:
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return @[]
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c.offset += read
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if not c.pad and buff.len > read:
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buff.setLen(read)
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return move buff
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func new*(
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T: type Chunker,
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reader: Reader,
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chunkSize = DefaultChunkSize,
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pad = true
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): Chunker =
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## create a new Chunker instance
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##
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Chunker(
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reader: reader,
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offset: 0,
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chunkSize: chunkSize,
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pad: pad)
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proc new*(
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T: type LPStreamChunker,
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stream: LPStream,
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chunkSize = DefaultChunkSize,
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pad = true
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): LPStreamChunker =
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## create the default File chunker
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##
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proc reader(data: ChunkBuffer, len: int): Future[int]
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{.gcsafe, async, raises: [Defect].} =
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var res = 0
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try:
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while res < len:
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res += await stream.readOnce(addr data[res], len - res)
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except LPStreamEOFError as exc:
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trace "LPStreamChunker stream Eof", exc = exc.msg
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except CatchableError as exc:
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trace "CatchableError exception", exc = exc.msg
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raise newException(Defect, exc.msg)
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return res
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LPStreamChunker.new(
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reader = reader,
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chunkSize = chunkSize,
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pad = pad)
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proc new*(
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T: type FileChunker,
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file: File,
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chunkSize = DefaultChunkSize,
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pad = true
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): FileChunker =
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## create the default File chunker
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##
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proc reader(data: ChunkBuffer, len: int): Future[int]
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{.gcsafe, async, raises: [Defect].} =
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var total = 0
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try:
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while total < len:
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let res = file.readBuffer(addr data[total], len - total)
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if res <= 0:
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break
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total += res
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except IOError as exc:
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trace "Exception reading file", exc = exc.msg
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except CatchableError as exc:
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trace "CatchableError exception", exc = exc.msg
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raise newException(Defect, exc.msg)
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return total
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FileChunker.new(
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reader = reader,
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chunkSize = chunkSize,
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pad = pad)
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