mirror of https://github.com/vacp2p/nim-libp2p.git
283 lines
8.5 KiB
Nim
283 lines
8.5 KiB
Nim
## Nim-LibP2P
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## Copyright (c) 2018 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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## This module implementes CID (Content IDentifier).
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{.push raises: [Defect].}
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import tables
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import multibase, multicodec, multihash, vbuffer, varint
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import stew/[base58, results]
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export results
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type
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CidError* {.pure.} = enum
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Error, Incorrect, Unsupported, Overrun
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CidVersion* = enum
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CIDvIncorrect, CIDv0, CIDv1, CIDvReserved
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Cid* = object
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cidver*: CidVersion
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mcodec*: MultiCodec
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hpos*: int
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data*: VBuffer
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const
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ContentIdsList = [
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multiCodec("raw"),
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multiCodec("dag-pb"),
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multiCodec("dag-cbor"),
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multiCodec("dag-json"),
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multiCodec("git-raw"),
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multiCodec("eth-block"),
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multiCodec("eth-block-list"),
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multiCodec("eth-tx-trie"),
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multiCodec("eth-tx"),
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multiCodec("eth-tx-receipt-trie"),
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multiCodec("eth-tx-receipt"),
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multiCodec("eth-state-trie"),
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multiCodec("eth-account-snapshot"),
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multiCodec("eth-storage-trie"),
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multiCodec("bitcoin-block"),
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multiCodec("bitcoin-tx"),
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multiCodec("zcash-block"),
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multiCodec("zcash-tx"),
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multiCodec("stellar-block"),
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multiCodec("stellar-tx"),
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multiCodec("decred-block"),
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multiCodec("decred-tx"),
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multiCodec("dash-block"),
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multiCodec("dash-tx"),
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multiCodec("torrent-info"),
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multiCodec("torrent-file"),
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multiCodec("ed25519-pub")
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]
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proc initCidCodeTable(): Table[int, MultiCodec] {.compileTime.} =
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result = initTable[int, MultiCodec]()
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for item in ContentIdsList:
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result[int(item)] = item
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const
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CodeContentIds = initCidCodeTable()
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template orError*(exp: untyped, err: untyped): untyped =
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(exp.mapErr do (_: auto) -> auto: err)
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proc decode(data: openarray[byte]): Result[Cid, CidError] =
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if len(data) == 34 and data[0] == 0x12'u8 and data[1] == 0x20'u8:
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ok(Cid(
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cidver: CIDv0,
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mcodec: multiCodec("dag-pb"),
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hpos: 0,
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data: initVBuffer(data)))
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else:
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var version, codec: uint64
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var res, offset: int
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var vb = initVBuffer(data)
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if vb.isEmpty():
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err(CidError.Incorrect)
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else:
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res = vb.readVarint(version)
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if res == -1:
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err(CidError.Incorrect)
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else:
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offset += res
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if version != 1'u64:
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err(CidError.Incorrect)
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else:
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res = vb.readVarint(codec)
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if res == -1:
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err(CidError.Incorrect)
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else:
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offset += res
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var mcodec = CodeContentIds.getOrDefault(cast[int](codec),
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InvalidMultiCodec)
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if mcodec == InvalidMultiCodec:
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err(CidError.Incorrect)
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else:
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if not MultiHash.validate(vb.buffer.toOpenArray(vb.offset,
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vb.buffer.high)):
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err(CidError.Incorrect)
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else:
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vb.finish()
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ok(Cid(
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cidver: CIDv1,
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mcodec: mcodec,
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hpos: offset,
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data: vb))
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proc decode(data: openarray[char]): Result[Cid, CidError] =
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var buffer: seq[byte]
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var plen = 0
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if len(data) < 2:
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return err(CidError.Incorrect)
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if len(data) == 46:
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if data[0] == 'Q' and data[1] == 'm':
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buffer = newSeq[byte](BTCBase58.decodedLength(len(data)))
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if BTCBase58.decode(data, buffer, plen) != Base58Status.Success:
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return err(CidError.Incorrect)
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buffer.setLen(plen)
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if len(buffer) == 0:
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let length = MultiBase.decodedLength(data[0], len(data))
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if length == -1:
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return err(CidError.Incorrect)
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buffer = newSeq[byte](length)
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if MultiBase.decode(data, buffer, plen) != MultiBaseStatus.Success:
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return err(CidError.Incorrect)
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buffer.setLen(plen)
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if buffer[0] == 0x12'u8:
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return err(CidError.Incorrect)
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decode(buffer)
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proc validate*(ctype: typedesc[Cid], data: openarray[byte]): bool =
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## Returns ``true`` is data has valid binary CID representation.
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var version, codec: uint64
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var res: VarintResult[void]
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if len(data) < 2:
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return false
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let last = data.high
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if len(data) == 34:
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if data[0] == 0x12'u8 and data[1] == 0x20'u8:
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return true
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var offset = 0
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var length = 0
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res = LP.getUVarint(data.toOpenArray(offset, last), length, version)
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if res.isErr():
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return false
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if version != 1'u64:
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return false
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offset += length
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if offset >= len(data):
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return false
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res = LP.getUVarint(data.toOpenArray(offset, last), length, codec)
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if res.isErr():
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return false
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var mcodec = CodeContentIds.getOrDefault(cast[int](codec), InvalidMultiCodec)
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if mcodec == InvalidMultiCodec:
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return false
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if not MultiHash.validate(data.toOpenArray(offset, last)):
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return false
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result = true
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proc mhash*(cid: Cid): Result[MultiHash, CidError] =
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## Returns MultiHash part of CID.
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if cid.cidver notin {CIDv0, CIDv1}:
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err(CidError.Incorrect)
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else:
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MultiHash.init(cid.data.buffer.toOpenArray(cid.hpos, cid.data.high)).orError(CidError.Incorrect)
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proc contentType*(cid: Cid): Result[MultiCodec, CidError] =
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## Returns content type part of CID
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if cid.cidver notin {CIDv0, CIDv1}:
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err(CidError.Incorrect)
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else:
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ok(cid.mcodec)
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proc version*(cid: Cid): CidVersion =
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## Returns CID version
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result = cid.cidver
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proc init*[T: char|byte](ctype: typedesc[Cid], data: openarray[T]): Result[Cid, CidError] =
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## Create new content identifier using array of bytes or string ``data``.
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decode(data)
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proc init*(ctype: typedesc[Cid], version: CidVersion, content: MultiCodec,
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hash: MultiHash): Result[Cid, CidError] =
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## Create new content identifier using content type ``content`` and
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## MultiHash ``hash`` using version ``version``.
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##
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## To create ``CIDv0`` you need to use:
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## Cid.init(CIDv0, multiCodec("dag-pb"), MultiHash.digest("sha2-256", data))
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##
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## All other encodings and hashes are not supported by CIDv0.
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var res: Cid
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res.cidver = version
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if version == CIDv0:
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if content != multiCodec("dag-pb"):
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return err(CidError.Unsupported)
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res.data = initVBuffer()
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if hash.mcodec != multiCodec("sha2-256"):
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return err(CidError.Unsupported)
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res.mcodec = content
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res.data.write(hash)
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res.data.finish()
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return ok(res)
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elif version == CIDv1:
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let mcodec = CodeContentIds.getOrDefault(cast[int](content),
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InvalidMultiCodec)
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if mcodec == InvalidMultiCodec:
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return err(CidError.Incorrect)
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res.mcodec = mcodec
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res.data = initVBuffer()
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res.data.writeVarint(cast[uint64](1))
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res.data.write(mcodec)
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res.hpos = len(res.data.buffer)
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res.data.write(hash)
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res.data.finish()
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return ok(res)
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else:
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return err(CidError.Unsupported)
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proc `==`*(a: Cid, b: Cid): bool =
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## Compares content identifiers ``a`` and ``b``, returns ``true`` if hashes
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## are equal, ``false`` otherwise.
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if a.mcodec == b.mcodec:
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var ah, bh: MultiHash
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if MultiHash.decode(
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a.data.buffer.toOpenArray(a.hpos, a.data.high), ah).isErr:
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return false
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if MultiHash.decode(
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b.data.buffer.toOpenArray(b.hpos, b.data.high), bh).isErr:
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return false
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result = (ah == bh)
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proc base58*(cid: Cid): string =
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## Get BASE58 encoded string representation of content identifier ``cid``.
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result = BTCBase58.encode(cid.data.buffer)
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proc hex*(cid: Cid): string =
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## Get hexadecimal string representation of content identifier ``cid``.
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result = $(cid.data)
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proc repr*(cid: Cid): string =
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## Get string representation of content identifier ``cid``.
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result = $(cid.cidver)
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result.add("/")
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result.add($(cid.mcodec))
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result.add("/")
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result.add($(cid.mhash()))
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proc write*(vb: var VBuffer, cid: Cid) {.inline.} =
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## Write CID value ``cid`` to buffer ``vb``.
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vb.writeArray(cid.data.buffer)
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proc encode*(mbtype: typedesc[MultiBase], encoding: string,
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cid: Cid): string {.inline.} =
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## Get MultiBase encoded representation of ``cid`` using encoding
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## ``encoding``.
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result = MultiBase.encode(encoding, cid.data.buffer).tryGet()
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proc `$`*(cid: Cid): string =
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## Return official string representation of content identifier ``cid``.
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if cid.cidver == CIDv0:
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BTCBase58.encode(cid.data.buffer)
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elif cid.cidver == CIDv1:
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let res = Multibase.encode("base58btc", cid.data.buffer)
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if res.isOk():
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res.get()
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else:
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""
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else:
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""
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