nim-codex/codex/manifest/manifest.nim

332 lines
8.3 KiB
Nim

## Nim-Codex
## 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.
# This module defines all operations on Manifest
import pkg/upraises
push: {.upraises: [].}
import pkg/libp2p/protobuf/minprotobuf
import pkg/libp2p
import pkg/questionable
import pkg/questionable/results
import pkg/chronicles
import ../errors
import ../utils
import ../units
import ../blocktype
import ./types
export types
type
Manifest* = ref object of RootObj
rootHash: ?Cid # Root (tree) hash of the contained data set
originalBytes*: NBytes # Exact size of the original (uploaded) file
blockSize: NBytes # Size of each contained block (might not be needed if blocks are len-prefixed)
blocks: seq[Cid] # Block Cid
version: CidVersion # Cid version
hcodec: MultiCodec # Multihash codec
codec: MultiCodec # Data set codec
case protected: bool # Protected datasets have erasure coded info
of true:
ecK: int # Number of blocks to encode
ecM: int # Number of resulting parity blocks
originalCid: Cid # The original Cid of the dataset being erasure coded
originalLen: int # The length of the original manifest
else:
discard
############################################################
# Accessors
############################################################
proc blockSize*(self: Manifest): NBytes =
self.blockSize
proc blocks*(self: Manifest): seq[Cid] =
self.blocks
proc version*(self: Manifest): CidVersion =
self.version
proc hcodec*(self: Manifest): MultiCodec =
self.hcodec
proc codec*(self: Manifest): MultiCodec =
self.codec
proc protected*(self: Manifest): bool =
self.protected
proc ecK*(self: Manifest): int =
self.ecK
proc ecM*(self: Manifest): int =
self.ecM
proc originalCid*(self: Manifest): Cid =
self.originalCid
proc originalLen*(self: Manifest): int =
self.originalLen
############################################################
# Operations on block list
############################################################
func len*(self: Manifest): int =
self.blocks.len
func `[]`*(self: Manifest, i: Natural): Cid =
self.blocks[i]
func `[]=`*(self: var Manifest, i: Natural, item: Cid) =
self.rootHash = Cid.none
self.blocks[i] = item
func `[]`*(self: Manifest, i: BackwardsIndex): Cid =
self.blocks[self.len - i.int]
func `[]=`*(self: Manifest, i: BackwardsIndex, item: Cid) =
self.rootHash = Cid.none
self.blocks[self.len - i.int] = item
func isManifest*(cid: Cid): ?!bool =
let res = ?cid.contentType().mapFailure(CodexError)
($(res) in ManifestContainers).success
func isManifest*(mc: MultiCodec): ?!bool =
($mc in ManifestContainers).success
proc add*(self: Manifest, cid: Cid) =
assert not self.protected # we expect that protected manifests are created with properly-sized self.blocks
self.rootHash = Cid.none
trace "Adding cid to manifest", cid
self.blocks.add(cid)
self.originalBytes = self.blocks.len.NBytes * self.blockSize
iterator items*(self: Manifest): Cid =
for b in self.blocks:
yield b
iterator pairs*(self: Manifest): tuple[key: int, val: Cid] =
for pair in self.blocks.pairs():
yield pair
func contains*(self: Manifest, cid: Cid): bool =
cid in self.blocks
############################################################
# Various sizes and verification
############################################################
func bytes*(self: Manifest, pad = true): NBytes =
## Compute how many bytes corresponding StoreStream(Manifest, pad) will return
if pad or self.protected:
self.len.NBytes * self.blockSize
else:
self.originalBytes
func rounded*(self: Manifest): int =
## Number of data blocks in *protected* manifest including padding at the end
roundUp(self.originalLen, self.ecK)
func steps*(self: Manifest): int =
## Number of EC groups in *protected* manifest
divUp(self.originalLen, self.ecK)
func verify*(self: Manifest): ?!void =
## Check manifest correctness
##
let originalLen = (if self.protected: self.originalLen else: self.len)
if divUp(self.originalBytes, self.blockSize) != originalLen:
return failure newException(CodexError, "Broken manifest: wrong originalBytes")
if self.protected and (self.len != self.steps * (self.ecK + self.ecM)):
return failure newException(CodexError, "Broken manifest: wrong originalLen")
return success()
############################################################
# Cid computation
############################################################
template hashBytes(mh: MultiHash): seq[byte] =
## get the hash bytes of a multihash object
##
mh.data.buffer[mh.dpos..(mh.dpos + mh.size - 1)]
proc makeRoot*(self: Manifest): ?!void =
## Create a tree hash root of the contained
## block hashes
##
var
stack: seq[MultiHash]
for cid in self:
stack.add(? cid.mhash.mapFailure)
while stack.len > 1:
let
(b1, b2) = (stack.pop(), stack.pop())
mh = ? MultiHash.digest(
$self.hcodec,
(b1.hashBytes() & b2.hashBytes()))
.mapFailure
stack.add(mh)
if stack.len == 1:
let digest = ? emptyDigest(self.version, self.hcodec)
let cid = ? Cid.init(self.version, self.codec, digest).mapFailure
self.rootHash = cid.some
success()
proc cid*(self: Manifest): ?!Cid =
## Generate a root hash using the treehash algorithm
##
if self.rootHash.isNone:
? self.makeRoot()
(!self.rootHash).success
############################################################
# Constructors
############################################################
proc new*(
T: type Manifest,
blocks: openArray[Cid] = [],
protected = false,
version = CIDv1,
hcodec = multiCodec("sha2-256"),
codec = multiCodec("raw"),
blockSize = DefaultBlockSize
): ?!Manifest =
## Create a manifest using an array of `Cid`s
##
# if hcodec notin EmptyDigests[version]:
# return failure("Unsupported manifest hash codec!")
T(
blocks: @blocks,
version: version,
codec: codec,
hcodec: hcodec,
blockSize: blockSize,
originalBytes: blocks.len.NBytes * blockSize,
protected: protected).success
proc new*(
T: type Manifest,
manifest: Manifest,
ecK, ecM: int
): ?!Manifest =
## Create an erasure protected dataset from an
## un-protected one
##
var
self = Manifest(
version: manifest.version,
codec: manifest.codec,
hcodec: manifest.hcodec,
originalBytes: manifest.originalBytes,
blockSize: manifest.blockSize,
protected: true,
ecK: ecK, ecM: ecM,
originalCid: ? manifest.cid,
originalLen: manifest.len)
let
encodedLen = self.rounded + (self.steps * ecM)
self.blocks = newSeq[Cid](encodedLen)
# copy original manifest blocks
for i in 0..<self.rounded:
if i < manifest.len:
self.blocks[i] = manifest[i]
else:
self.blocks[i] = emptyCid(manifest.version, manifest.hcodec).get()
? self.verify()
self.success
proc new*(
T: type Manifest,
data: openArray[byte],
decoder = ManifestContainers[$DagPBCodec]
): ?!Manifest =
## Create a manifest instance from given data
##
Manifest.decode(data, decoder)
proc new*(
T: type Manifest,
rootHash: Cid,
originalBytes: NBytes,
blockSize: NBytes,
blocks: seq[Cid],
version: CidVersion,
hcodec: MultiCodec,
codec: MultiCodec,
ecK: int,
ecM: int,
originalCid: Cid,
originalLen: int
): Manifest =
Manifest(
rootHash: rootHash.some,
originalBytes: originalBytes,
blockSize: blockSize,
blocks: blocks,
version: version,
hcodec: hcodec,
codec: codec,
protected: true,
ecK: ecK,
ecM: ecM,
originalCid: originalCid,
originalLen: originalLen
)
proc new*(
T: type Manifest,
rootHash: Cid,
originalBytes: NBytes,
blockSize: NBytes,
blocks: seq[Cid],
version: CidVersion,
hcodec: MultiCodec,
codec: MultiCodec
): Manifest =
Manifest(
rootHash: rootHash.some,
originalBytes: originalBytes,
blockSize: blockSize,
blocks: blocks,
version: version,
hcodec: hcodec,
codec: codec,
protected: false,
)