nim-dagger/codex/blocktype.nim

157 lines
3.2 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
export tables
import pkg/upraises
push: {.upraises: [].}
import pkg/libp2p
import pkg/stew/byteutils
import pkg/questionable
import pkg/questionable/results
import ./errors
const
BlockSize* = 31 * 64 * 4 # block size
type
Block* = ref object of RootObj
cid*: Cid
data*: seq[byte]
template EmptyCid*: untyped =
var
emptyCid {.global, threadvar.}:
array[CIDv0..CIDv1, Table[MultiCodec, Cid]]
once:
emptyCid = [
CIDv0: {
multiCodec("sha2-256"): Cid
.init("QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n")
.get()
}.toTable,
CIDv1: {
multiCodec("sha2-256"): Cid
.init("bafybeihdwdcefgh4dqkjv67uzcmw7ojee6xedzdetojuzjevtenxquvyku")
.get()
}.toTable,
]
emptyCid
template EmptyDigests*: untyped =
var
emptyDigests {.global, threadvar.}:
array[CIDv0..CIDv1, Table[MultiCodec, MultiHash]]
once:
emptyDigests = [
CIDv0: {
multiCodec("sha2-256"): EmptyCid[CIDv0]
.catch
.get()[multiCodec("sha2-256")]
.catch
.get()
.mhash
.get()
}.toTable,
CIDv1: {
multiCodec("sha2-256"): EmptyCid[CIDv1]
.catch
.get()[multiCodec("sha2-256")]
.catch
.get()
.mhash
.get()
}.toTable,
]
emptyDigests
template EmptyBlock*: untyped =
var
emptyBlock {.global, threadvar.}:
array[CIDv0..CIDv1, Table[MultiCodec, Block]]
once:
emptyBlock = [
CIDv0: {
multiCodec("sha2-256"): Block(
cid: EmptyCid[CIDv0][multiCodec("sha2-256")])
}.toTable,
CIDv1: {
multiCodec("sha2-256"): Block(
cid: EmptyCid[CIDv1][multiCodec("sha2-256")])
}.toTable,
]
emptyBlock
proc isEmpty*(cid: Cid): bool =
cid == EmptyCid[cid.cidver]
.catch
.get()[cid.mhash.get().mcodec]
.catch
.get()
proc isEmpty*(blk: Block): bool =
blk.cid.isEmpty
proc emptyBlock*(cid: Cid): Block =
EmptyBlock[cid.cidver]
.catch
.get()[cid.mhash.get().mcodec]
.catch
.get()
proc `$`*(b: Block): string =
result &= "cid: " & $b.cid
result &= "\ndata: " & string.fromBytes(b.data)
func new*(
T: type Block,
data: openArray[byte] = [],
version = CIDv1,
mcodec = multiCodec("sha2-256"),
codec = multiCodec("raw")): ?!T =
let
hash = ? MultiHash.digest($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): ?!T =
let
mhash = ? cid.mhash.mapFailure
b = ? Block.new(
data = @data,
version = cid.cidver,
codec = cid.mcodec,
mcodec = mhash.mcodec)
if verify and cid != b.cid:
return "Cid and content don't match!".failure
success b