nimbus-eth1/nimbus/db/aristo/aristo_desc/desc_identifiers.nim

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15 KiB
Nim

# nimbus-eth1
# Copyright (c) 2023-2024 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed
# except according to those terms.
## Aristo DB -- Identifier types
## =============================
##
{.push raises: [].}
import
std/[algorithm, sequtils, sets, strutils, hashes],
eth/common,
stew/byteutils,
chronicles,
results,
stint,
./desc_nibbles
export
desc_nibbles
type
VertexID* = distinct uint64
## Unique identifier for a vertex of the `Aristo Trie`. The vertex is the
## prefix tree (aka `Patricia Trie`) component. When augmented by hash
## keys, the vertex component will be called a node. On the persistent
## backend of the database, there is no other reference to the node than
## the very same `VertexID`.
##
## Vertex IDs are generated on the fly and thrown away when not needed,
## anymore. They are not recycled. A quick estimate
##
## (2^64) / (100 * 365.25 * 24 * 3600) / 1000 / 1000 / 1000 = 5.86
##
## shows that the `uint64` scalar space is not exhausted in a 100 years
## if the database consumes somewhat less than 6 IDs per nanosecond.
##
## A simple recycling mechanism was tested which slowed down the system
## considerably because large swaths of database vertices were regularly
## freed so recycling had do deal with extensive lists of non-consecutive
## IDs.
RootedVertexID* = tuple[root, vid: VertexID]
## Vertex and the root it belongs to in the MPT. Used to group a set of
## verticies, for example to store them together in the database or perform
## range operations.
##
## `vid` may be a branch, extension or leaf.
##
## To reference the root itself, use (root, root).
HashKey* = object
## Ethereum reference MPTs use Keccak hashes as node links if the size of
## an RLP encoded node is at least 32 bytes. Otherwise, the RLP encoded
## node value is used as a pseudo node link (rather than a hash.) This is
## specified in the yellow paper, appendix D. Only for the root hash, the
## top level node is always referred to by the Keccak hash.
##
## On the `Aristo` database node links are called keys which are of this
## very type `HashKey`. For key-value tables (which assign a key to a
## vertex), the keys are always stored as such with length probably
## smaller than 32, including for root vertex keys. Only when used as a
## root state, the key of the latter is digested to a Keccak hash
## on-the-fly.
##
## This compaction feature nees an abstraction of the hash link object
## which is either a `Hash256` or a `Blob` of length at most 31 bytes.
## This leaves two ways of representing an empty/void `HashKey` type.
## It may be available as an empty `Blob` of zero length, or the
## `Hash256` type of the Keccak hash of an empty `Blob` (see constant
## `EMPTY_ROOT_HASH`.)
##
## For performance, storing blobs as `seq` is avoided, instead storing
## their length and sharing the data "space".
##
buf: array[32, byte] # Either Hash256 or blob data, depending on `len`
len: int8 # length in the case of blobs, or 32 when it's a hash
PathID* = object
## Path into the `Patricia Trie`. This is a chain of maximal 64 nibbles
## (which is 32 bytes.) In most cases, the length is 64. So the path is
## encoded as a numeric value which is often easier to handle than a
## chain of nibbles.
##
## The path ID should be kept normalised, i.e.
## * 0 <= `length` <= 64
## * the unused trailing nibbles in `pfx` are set to `0`
##
pfx*: UInt256
length*: uint8
# ----------
LeafTie* = object
## Unique access key for a leaf vertex. It identifies a root vertex
## followed by a nibble path along the `Patricia Trie` down to a leaf
## vertex. So this implies an obvious injection from the set of `LeafTie`
## objects *into* the set of `VertexID` obvious (which is typically *into*
## only, not a bijection.)
##
## Note that `LeafTie` objects have no representation in the `Aristo Trie`.
## They are used temporarily and in caches or backlog tables.
root*: VertexID ## Root ID for the sub-trie
path*: PathID ## Path into the `Patricia Trie`
# ------------------------------------------------------------------------------
# Chronicles formatters
# ------------------------------------------------------------------------------
chronicles.formatIt(VertexID): $it
# ------------------------------------------------------------------------------
# Public helpers: `VertexID` scalar data model
# ------------------------------------------------------------------------------
func `<`*(a, b: VertexID): bool {.borrow.}
func `<=`*(a, b: VertexID): bool {.borrow.}
func `==`*(a, b: VertexID): bool {.borrow.}
func cmp*(a, b: VertexID): int {.borrow.}
func `$`*(vid: VertexID): string =
"$" & (if vid == VertexID(0): "ø"
else: vid.uint64.toHex.strip(trailing=false,chars={'0'}).toLowerAscii)
func `$`*(rvid: RootedVertexID): string =
$rvid.root & "/" & $rvid.vid
func `==`*(a: VertexID; b: static[uint]): bool = (a == VertexID(b))
# Scalar model extension as in `IntervalSetRef[VertexID,uint64]`
func `+`*(a: VertexID; b: uint64): VertexID = (a.uint64+b).VertexID
func `-`*(a: VertexID; b: uint64): VertexID = (a.uint64-b).VertexID
func `-`*(a, b: VertexID): uint64 = (a.uint64 - b.uint64)
# ------------------------------------------------------------------------------
# Public helpers: `PathID` ordered scalar data model
# ------------------------------------------------------------------------------
func high*(_: type PathID): PathID =
## Highest possible `PathID` object for given root vertex.
PathID(pfx: high(UInt256), length: 64)
func low*(_: type PathID): PathID =
## Lowest possible `PathID` object for given root vertex.
PathID()
func next*(pid: PathID): PathID =
## Return a `PathID` object with incremented path field. This function might
## return also a modified `length` field.
##
## The function returns the argument `pid` if it is already at its
## maximum value `high(PathID)`.
if pid.pfx.isZero and pid.length < 64:
PathID(length: pid.length + 1)
elif pid.pfx < high(UInt256):
PathID(pfx: pid.pfx + 1, length: 64)
else:
pid
func prev*(pid: PathID): PathID =
## Return a `PathID` object with decremented path field. This function might
## return also a modified `length` field.
##
## The function returns the argument `pid` if it is already at its
## minimum value `low(PathID)`.
if 0 < pid.pfx:
PathID(pfx: pid.pfx - 1, length: 64)
elif 0 < pid.length:
PathID(length: pid.length - 1)
else:
pid
func `<`*(a, b: PathID): bool =
## This function assumes that the arguments `a` and `b` are normalised
## (see `normal()`.)
a.pfx < b.pfx or (a.pfx == b.pfx and a.length < b.length)
func `<=`*(a, b: PathID): bool =
not (b < a)
func `==`*(a, b: PathID): bool =
## This function assumes that the arguments `a` and `b` are normalised
## (see `normal()`.)
a.pfx == b.pfx and a.length == b.length
func cmp*(a, b: PathID): int =
if a < b: -1 elif b < a: 1 else: 0
# ------------------------------------------------------------------------------
# Public helpers: `HashKey` ordered scalar data model
# ------------------------------------------------------------------------------
func len*(lid: HashKey): int =
lid.len.int # if lid.isHash: 32 else: lid.blob.len
template data*(lid: HashKey): openArray[byte] =
lid.buf.toOpenArray(0, lid.len - 1)
func to*(lid: HashKey; T: type PathID): T =
## Helper to bowrrow certain properties from `PathID`
if lid.len == 32:
PathID(pfx: UInt256.fromBytesBE lid.data, length: 64)
elif 0 < lid.len:
doAssert lid.len < 32
var a32: array[32,byte]
(addr a32[0]).copyMem(unsafeAddr lid.data[0], lid.len)
PathID(pfx: UInt256.fromBytesBE a32, length: 2 * lid.len.uint8)
else:
PathID()
func fromBytes*(T: type HashKey; data: openArray[byte]): Result[T,void] =
## Write argument `data` of length 0 or between 2 and 32 bytes as a `HashKey`.
##
## A function argument `data` of length 32 is used as-is.
##
## For a function argument `data` of length between 2 and 31, the first
## byte must be the start of an RLP encoded list, i.e. `0xc0 + len` where
## where `len` is one less as the `data` length.
##
if data.len == 32:
var lid: T
lid.len = 32
(addr lid.data[0]).copyMem(unsafeAddr data[0], data.len)
return ok lid
if data.len == 0:
return ok HashKey()
if 1 < data.len and data.len < 32 and data[0].int == 0xbf + data.len:
var lid: T
lid.len = int8 data.len
(addr lid.data[0]).copyMem(unsafeAddr data[0], data.len)
return ok lid
err()
func `<`*(a, b: HashKey): bool =
## Slow, but useful for debug sorting
a.to(PathID) < b.to(PathID)
func `==`*(a, b: HashKey): bool =
a.data == b.data
func cmp*(a, b: HashKey): int =
## Slow, but useful for debug sorting
cmp(a.data, b.data)
# ------------------------------------------------------------------------------
# Public helpers: `LeafTie` ordered scalar data model
# ------------------------------------------------------------------------------
func high*(_: type LeafTie; root = VertexID(1)): LeafTie =
## Highest possible `LeafTie` object for given root vertex.
LeafTie(root: root, path: high(PathID))
func low*(_: type LeafTie; root = VertexID(1)): LeafTie =
## Lowest possible `LeafTie` object for given root vertex.
LeafTie(root: root, path: low(PathID))
func next*(lty: LeafTie): LeafTie =
## Return a `LeafTie` object with the `next()` path field.
LeafTie(root: lty.root, path: lty.path.next)
func prev*(lty: LeafTie): LeafTie =
## Return a `LeafTie` object with the `prev()` path field.
LeafTie(root: lty.root, path: lty.path.prev)
func `<`*(a, b: LeafTie): bool =
## This function assumes that the arguments `a` and `b` are normalised
## (see `normal()`.)
a.root < b.root or (a.root == b.root and a.path < b.path)
func `==`*(a, b: LeafTie): bool =
## This function assumes that the arguments `a` and `b` are normalised
## (see `normal()`.)
a.root == b.root and a.path == b.path
func cmp*(a, b: LeafTie): int =
## This function assumes that the arguments `a` and `b` are normalised
## (see `normal()`.)
if a < b: -1 elif a == b: 0 else: 1
# ------------------------------------------------------------------------------
# Public helpers: Reversible conversions between `PathID`, `HashKey`, etc.
# ------------------------------------------------------------------------------
func to*(pid: PathID; T: type NibblesBuf): T =
## Representation of a `PathID` as `NibbleSeq` (preserving full information)
let nibbles = NibblesBuf.fromBytes(pid.pfx.toBytesBE)
if pid.length < 64:
nibbles.slice(0, pid.length.int)
else:
nibbles
func `@`*(pid: PathID): Blob =
## Representation of a `PathID` as a `Blob`. The result is left padded
## by a zero LSB if the path length was odd.
result = pid.pfx.toBytesBE.toSeq
if pid.length < 63:
result.setLen((pid.length + 1) shl 1)
func to*(lid: HashKey; T: type Hash256): T =
## Returns the `Hash236` key if available, otherwise the Keccak hash of
## the `Blob` version.
if lid.len == 32:
Hash256(data: lid.buf)
elif 0 < lid.len:
lid.data.keccakHash
else:
EMPTY_ROOT_HASH
func to*(key: Hash256; T: type HashKey): T =
## This is an efficient version of `HashKey.fromBytes(key.data).value`, not
## to be confused with `digestTo(HashKey)`.
if key == EMPTY_ROOT_HASH:
T()
else:
T(len: 32, buf: key.data)
func to*(n: SomeUnsignedInt; T: type PathID): T =
## Representation of a scalar as `PathID` (preserving full information)
T(pfx: n.u256, length: 64)
func to*(n: UInt256; T: type PathID): T =
## Representation of a scalar as `PathID` (preserving full information)
T(pfx: n, length: 64)
func to*(a: PathID; T: type UInt256): T =
if not a.pfx.isZero:
assert a.length < 64 # debugging only
result = a.pfx shr (4 * (64 - a.length))
# ------------------------------------------------------------------------------
# Public helpers: Miscellaneous mappings
# ------------------------------------------------------------------------------
func digestTo*(data: openArray[byte]; T: type HashKey): T =
## For argument `data` with length smaller than 32, import them as-is into
## the result. Otherwise import the Keccak hash of the argument `data`.
##
## The `data` argument is only hashed if the `data` length is at least
## 32 bytes. Otherwise it is converted as-is to a `HashKey` type result.
##
## Note that for calculating a root state (when `data` is a serialised
## vertex), one would use the expression `data.digestTo(HashKey).to(Hash256)`
## which would always hash the `data` argument regardless of its length
## (and might result in an `EMPTY_ROOT_HASH`.) See the comment at the
## definition of the `HashKey` type for an explanation of its usage.
##
if data.len == 0:
result.len = 0
elif data.len < 32:
result.len = int8 data.len
(addr result.data[0]).copyMem(unsafeAddr data[0], data.len)
else:
result.len = 32
result.buf = data.keccakHash.data
func normal*(a: PathID): PathID =
## Normalise path ID representation
result = a
if 64 < a.length:
result.length = 64
elif a.length < 64:
result.pfx = a.pfx and not (1.u256 shl (4 * (64 - a.length))) - 1.u256
# ------------------------------------------------------------------------------
# Public helpers: `Tables` and `Rlp` support
# ------------------------------------------------------------------------------
func hash*(a: PathID): Hash =
## Table/KeyedQueue mixin
var h: Hash = 0
h = h !& a.pfx.toBytesBE.hash
h = h !& a.length.hash
!$h
func hash*(a: HashKey): Hash =
## Table/KeyedQueue mixin
hash(a.data)
# ------------------------------------------------------------------------------
# Miscellaneous helpers
# ------------------------------------------------------------------------------
func `$`*(vids: seq[VertexID]): string =
"[" & vids.toSeq.mapIt(
"$" & it.uint64.toHex.strip(trailing=false,chars={'0'})
).join(",") & "]"
func `$`*(vids: HashSet[VertexID]): string =
"{" & vids.toSeq.sorted.mapIt(
"$" & it.uint64.toHex.strip(trailing=false,chars={'0'})
).join(",") & "}"
func `$`*(key: HashKey): string =
toHex(key.data)
func `$`*(a: PathID): string =
if a.pfx.isZero.not:
var dgts = $a.pfx.toHex
if a.length < 64:
dgts = dgts[0 ..< a.length]
result = dgts.strip(
leading=true, trailing=false, chars={'0'})
elif a.length != 0:
result = "0"
if a.length < 64:
result &= "(" & $a.length & ")"
func `$`*(a: LeafTie): string =
if a.root != 0:
result = ($a.root.uint64.toHex).strip(
leading=true, trailing=false, chars={'0'})
else:
result = "0"
result &= ":" & $a.path
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------