nim-codex/codex/blocktype.nim

173 lines
4.7 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 std/tables
import std/sugar
export tables
import pkg/upraises
push: {.upraises: [].}
import pkg/libp2p/[cid, multicodec, multihash]
import pkg/stew/byteutils
import pkg/questionable
import pkg/questionable/results
import pkg/chronicles
import pkg/json_serialization
import ./units
import ./utils
import ./formats
import ./errors
export errors, formats, units
const
# Size of blocks for storage / network exchange,
# should be divisible by 31 for PoR and by 64 for Leopard ECC
DefaultBlockSize* = NBytes 31 * 64 * 33
type
Block* = ref object of RootObj
cid*: Cid
data*: seq[byte]
BlockAddress* = object
case leaf*: bool
of true:
treeCid*: Cid
index*: Natural
else:
cid*: Cid
proc `==`*(a, b: BlockAddress): bool =
a.leaf == b.leaf and
(
if a.leaf:
a.treeCid == b.treeCid and a.index == b.index
else:
a.cid == b.cid
)
proc `$`*(a: BlockAddress): string =
if a.leaf:
"treeCid: " & $a.treeCid & ", index: " & $a.index
else:
"cid: " & $a.cid
proc writeValue*(
writer: var JsonWriter,
value: Cid
) {.upraises:[IOError].} =
writer.writeValue($value)
proc cidOrTreeCid*(a: BlockAddress): Cid =
if a.leaf:
a.treeCid
else:
a.cid
proc address*(b: Block): BlockAddress =
BlockAddress(leaf: false, cid: b.cid)
proc init*(_: type BlockAddress, cid: Cid): BlockAddress =
BlockAddress(leaf: false, cid: cid)
proc init*(_: type BlockAddress, treeCid: Cid, index: Natural): BlockAddress =
BlockAddress(leaf: true, treeCid: treeCid, index: index)
proc `$`*(b: Block): string =
result &= "cid: " & $b.cid
result &= "\ndata: " & string.fromBytes(b.data)
func new*(
T: type Block,
data: openArray[byte] = [],
version = CIDv1,
mcodec = multiCodec("sha2-256"),
codec = multiCodec("raw")
): ?!Block =
## creates a new block for both storage and network IO
##
let
hash = ? MultiHash.digest($mcodec, data).mapFailure
cid = ? Cid.init(version, codec, hash).mapFailure
# TODO: If the hash is `>=` to the data,
# use the Cid as a container!
Block(
cid: cid,
data: @data).success
func new*(
T: type Block,
cid: Cid,
data: openArray[byte],
verify: bool = true
): ?!Block =
## creates a new block for both storage and network IO
##
if verify:
let
mhash = ? cid.mhash.mapFailure
computedMhash = ? MultiHash.digest($mhash.mcodec, data).mapFailure
computedCid = ? Cid.init(cid.cidver, cid.mcodec, computedMhash).mapFailure
if computedCid != cid:
return "Cid doesn't match the data".failure
return Block(
cid: cid,
data: @data
).success
proc emptyCid*(version: CidVersion, hcodec: MultiCodec, dcodec: MultiCodec): ?!Cid =
## Returns cid representing empty content, given cid version, hash codec and data codec
##
const
Sha256 = multiCodec("sha2-256")
Raw = multiCodec("raw")
DagPB = multiCodec("dag-pb")
DagJson = multiCodec("dag-json")
var index {.global, threadvar.}: Table[(CidVersion, MultiCodec, MultiCodec), Cid]
once:
index = {
# source https://ipld.io/specs/codecs/dag-pb/fixtures/cross-codec/#dagpb_empty
(CIDv0, Sha256, DagPB): ? Cid.init("QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n").mapFailure,
(CIDv1, Sha256, DagPB): ? Cid.init("zdj7Wkkhxcu2rsiN6GUyHCLsSLL47kdUNfjbFqBUUhMFTZKBi").mapFailure, # base36: bafybeihdwdcefgh4dqkjv67uzcmw7ojee6xedzdetojuzjevtenxquvyku
(CIDv1, Sha256, DagJson): ? Cid.init("z4EBG9jGUWMVxX9deANWX7iPyExLswe2akyF7xkNAaYgugvnhmP").mapFailure, # base36: baguqeera6mfu3g6n722vx7dbitpnbiyqnwah4ddy4b5c3rwzxc5pntqcupta
(CIDv1, Sha256, Raw): ? Cid.init("zb2rhmy65F3REf8SZp7De11gxtECBGgUKaLdiDj7MCGCHxbDW").mapFailure,
}.toTable
index[(version, hcodec, dcodec)].catch
proc emptyDigest*(version: CidVersion, hcodec: MultiCodec, dcodec: MultiCodec): ?!MultiHash =
emptyCid(version, hcodec, dcodec)
.flatMap((cid: Cid) => cid.mhash.mapFailure)
proc emptyBlock*(version: CidVersion, hcodec: MultiCodec): ?!Block =
emptyCid(version, hcodec, multiCodec("raw"))
.flatMap((cid: Cid) => Block.new(cid = cid, data = @[]))
proc emptyBlock*(cid: Cid): ?!Block =
cid.mhash.mapFailure.flatMap((mhash: MultiHash) =>
emptyBlock(cid.cidver, mhash.mcodec))
proc isEmpty*(cid: Cid): bool =
success(cid) == cid.mhash.mapFailure.flatMap((mhash: MultiHash) =>
emptyCid(cid.cidver, mhash.mcodec, cid.mcodec))
proc isEmpty*(blk: Block): bool =
blk.cid.isEmpty