nimbus-eth1/nimbus/db/aristo/aristo_merge.nim

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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 -- Patricia Trie builder, raw node insertion
## ======================================================
##
## This module merges `PathID` values as hexary lookup paths into the
## `Patricia Trie`. When changing vertices (aka nodes without Merkle hashes),
## associated (but separated) Merkle hashes will be deleted unless locked.
## Instead of deleting locked hashes error handling is applied.
##
## Also, nodes (vertices plus merkle hashes) can be added which is needed for
## boundary proofing after `snap/1` download. The vertices are split from the
## nodes and stored as-is on the table holding `Patricia Trie` entries. The
## hashes are stored iin a separate table and the vertices are labelled
## `locked`.
{.push raises: [].}
import
std/[algorithm, sequtils, strutils, sets, tables, typetraits],
chronicles,
eth/[common, trie/nibbles],
results,
stew/keyed_queue,
../../sync/protocol/snap/snap_types,
"."/[aristo_desc, aristo_get, aristo_hike, aristo_layers,
aristo_path, aristo_serialise, aristo_utils, aristo_vid]
logScope:
topics = "aristo-merge"
type
LeafTiePayload* = object
## Generalised key-value pair for a sub-trie. The main trie is the
## sub-trie with `root=VertexID(1)`.
leafTie*: LeafTie ## Full `Patricia Trie` path root-to-leaf
payload*: PayloadRef ## Leaf data payload
# ------------------------------------------------------------------------------
# Private getters & setters
# ------------------------------------------------------------------------------
proc xPfx(vtx: VertexRef): NibblesSeq =
case vtx.vType:
of Leaf:
return vtx.lPfx
of Extension:
return vtx.ePfx
of Branch:
doAssert vtx.vType != Branch # Ooops
# ------------------------------------------------------------------------------
# Private helpers
# ------------------------------------------------------------------------------
proc to(
rc: Result[Hike,AristoError];
T: type Result[bool,AristoError];
): T =
## Return code converter
if rc.isOk:
ok true
elif rc.error in {MergeLeafPathCachedAlready,
MergeLeafPathOnBackendAlready}:
ok false
else:
err(rc.error)
# -----------
proc clearMerkleKeys(
db: AristoDbRef; # Database, top layer
hike: Hike; # Implied vertex IDs to clear hashes for
vid: VertexID; # Additionall vertex IDs to clear
) =
for w in hike.legs.mapIt(it.wp.vid) & @[vid]:
db.layersResKey(hike.root, w)
proc setVtxAndKey(
db: AristoDbRef; # Database, top layer
root: VertexID;
vid: VertexID; # Vertex IDs to add/clear
vtx: VertexRef; # Vertex to add
) =
db.layersPutVtx(root, vid, vtx)
db.layersResKey(root, vid)
# -----------
proc insertBranch(
db: AristoDbRef; # Database, top layer
hike: Hike; # Current state
linkID: VertexID; # Vertex ID to insert
linkVtx: VertexRef; # Vertex to insert
payload: PayloadRef; # Leaf data payload
): Result[Hike,AristoError] =
##
## Insert `Extension->Branch` vertex chain or just a `Branch` vertex
##
## ... --(linkID)--> <linkVtx>
##
## <-- immutable --> <---- mutable ----> ..
##
## will become either
##
## --(linkID)-->
## <extVtx> --(local1)-->
## <forkVtx>[linkInx] --(local2)--> <linkVtx*>
## [leafInx] --(local3)--> <leafVtx>
##
## or in case that there is no common prefix
##
## --(linkID)-->
## <forkVtx>[linkInx] --(local2)--> <linkVtx*>
## [leafInx] --(local3)--> <leafVtx>
##
## *) vertex was slightly modified or removed if obsolete `Extension`
##
let n = linkVtx.xPfx.sharedPrefixLen hike.tail
# Verify minimum requirements
if hike.tail.len == n:
# Should have been tackeld by `hikeUp()`, already
return err(MergeLeafGarbledHike)
if linkVtx.xPfx.len == n:
return err(MergeBranchLinkVtxPfxTooShort)
# Provide and install `forkVtx`
let
forkVtx = VertexRef(vType: Branch)
linkInx = linkVtx.xPfx[n]
leafInx = hike.tail[n]
var
leafLeg = Leg(nibble: -1)
# Install `forkVtx`
block:
# Clear Merkle hashes (aka hash keys) unless proof mode.
if db.pPrf.len == 0:
db.clearMerkleKeys(hike, linkID)
elif linkID in db.pPrf:
return err(MergeNonBranchProofModeLock)
if linkVtx.vType == Leaf:
# Update vertex path lookup
let
path = hike.legsTo(NibblesSeq) & linkVtx.lPfx
rc = path.pathToTag()
if rc.isErr:
debug "Branch link leaf path garbled", linkID, path
return err(MergeBranchLinkLeafGarbled)
let
local = db.vidFetch(pristine = true)
lty = LeafTie(root: hike.root, path: rc.value)
db.setVtxAndKey(hike.root, local, linkVtx)
linkVtx.lPfx = linkVtx.lPfx.slice(1+n)
forkVtx.bVid[linkInx] = local
elif linkVtx.ePfx.len == n + 1:
# This extension `linkVtx` becomes obsolete
forkVtx.bVid[linkInx] = linkVtx.eVid
else:
let local = db.vidFetch
db.setVtxAndKey(hike.root, local, linkVtx)
linkVtx.ePfx = linkVtx.ePfx.slice(1+n)
forkVtx.bVid[linkInx] = local
block:
let local = db.vidFetch(pristine = true)
forkVtx.bVid[leafInx] = local
leafLeg.wp.vid = local
leafLeg.wp.vtx = VertexRef(
vType: Leaf,
lPfx: hike.tail.slice(1+n),
lData: payload)
db.setVtxAndKey(hike.root, local, leafLeg.wp.vtx)
# Update branch leg, ready to append more legs
var okHike = Hike(root: hike.root, legs: hike.legs)
# Update in-beween glue linking `branch --[..]--> forkVtx`
if 0 < n:
let extVtx = VertexRef(
vType: Extension,
ePfx: hike.tail.slice(0,n),
eVid: db.vidFetch)
db.setVtxAndKey(hike.root, linkID, extVtx)
okHike.legs.add Leg(
nibble: -1,
wp: VidVtxPair(
vid: linkID,
vtx: extVtx))
db.setVtxAndKey(hike.root, extVtx.eVid, forkVtx)
okHike.legs.add Leg(
nibble: leafInx.int8,
wp: VidVtxPair(
vid: extVtx.eVid,
vtx: forkVtx))
else:
db.setVtxAndKey(hike.root, linkID, forkVtx)
okHike.legs.add Leg(
nibble: leafInx.int8,
wp: VidVtxPair(
vid: linkID,
vtx: forkVtx))
okHike.legs.add leafLeg
ok okHike
proc concatBranchAndLeaf(
db: AristoDbRef; # Database, top layer
hike: Hike; # Path top has a `Branch` vertex
brVid: VertexID; # Branch vertex ID from from `Hike` top
brVtx: VertexRef; # Branch vertex, linked to from `Hike`
payload: PayloadRef; # Leaf data payload
): Result[Hike,AristoError] =
## Append argument branch vertex passed as argument `(brID,brVtx)` and then
## a `Leaf` vertex derived from the argument `payload`.
##
if hike.tail.len == 0:
return err(MergeBranchGarbledTail)
let nibble = hike.tail[0].int8
if brVtx.bVid[nibble].isValid:
return err(MergeRootBranchLinkBusy)
# Clear Merkle hashes (aka hash keys) unless proof mode.
if db.pPrf.len == 0:
db.clearMerkleKeys(hike, brVid)
elif brVid in db.pPrf:
return err(MergeBranchProofModeLock) # Ooops
# Append branch vertex
var okHike = Hike(root: hike.root, legs: hike.legs)
okHike.legs.add Leg(wp: VidVtxPair(vtx: brVtx, vid: brVid), nibble: nibble)
# Append leaf vertex
let
vid = db.vidFetch(pristine = true)
vtx = VertexRef(
vType: Leaf,
lPfx: hike.tail.slice(1),
lData: payload)
brVtx.bVid[nibble] = vid
db.setVtxAndKey(hike.root, brVid, brVtx)
db.setVtxAndKey(hike.root, vid, vtx)
okHike.legs.add Leg(wp: VidVtxPair(vtx: vtx, vid: vid), nibble: -1)
ok okHike
# ------------------------------------------------------------------------------
# Private functions: add Particia Trie leaf vertex
# ------------------------------------------------------------------------------
proc topIsBranchAddLeaf(
db: AristoDbRef; # Database, top layer
hike: Hike; # Path top has a `Branch` vertex
payload: PayloadRef; # Leaf data payload
): Result[Hike,AristoError] =
## Append a `Leaf` vertex derived from the argument `payload` after the top
## leg of the `hike` argument which is assumend to refert to a `Branch`
## vertex. If successful, the function returns the updated `hike` trail.
if hike.tail.len == 0:
return err(MergeBranchGarbledTail)
let nibble = hike.legs[^1].nibble
if nibble < 0:
return err(MergeBranchGarbledNibble)
let
parent = hike.legs[^1].wp.vid
branch = hike.legs[^1].wp.vtx
linkID = branch.bVid[nibble]
linkVtx = db.getVtx linkID
if not linkVtx.isValid:
#
# .. <branch>[nibble] --(linkID)--> nil
#
# <-------- immutable ------------> <---- mutable ----> ..
#
if db.pPrf.len == 0:
# Not much else that can be done here
debug "Dangling leaf link, reused", branch=hike.legs[^1].wp.vid,
nibble, linkID, leafPfx=hike.tail
# Reuse placeholder entry in table
let vtx = VertexRef(
vType: Leaf,
lPfx: hike.tail,
lData: payload)
db.setVtxAndKey(hike.root, linkID, vtx)
var okHike = Hike(root: hike.root, legs: hike.legs)
okHike.legs.add Leg(wp: VidVtxPair(vid: linkID, vtx: vtx), nibble: -1)
if parent notin db.pPrf:
db.layersResKey(hike.root, parent)
return ok(okHike)
if linkVtx.vType == Branch:
# Slot link to a branch vertex should be handled by `hikeUp()`
#
# .. <branch>[nibble] --(linkID)--> <linkVtx>[]
#
# <-------- immutable ------------> <---- mutable ----> ..
#
return db.concatBranchAndLeaf(hike, linkID, linkVtx, payload)
db.insertBranch(hike, linkID, linkVtx, payload)
proc topIsExtAddLeaf(
db: AristoDbRef; # Database, top layer
hike: Hike; # Path top has an `Extension` vertex
payload: PayloadRef; # Leaf data payload
): Result[Hike,AristoError] =
## Append a `Leaf` vertex derived from the argument `payload` after the top
## leg of the `hike` argument which is assumend to refert to a `Extension`
## vertex. If successful, the function returns the
## updated `hike` trail.
let
extVtx = hike.legs[^1].wp.vtx
extVid = hike.legs[^1].wp.vid
brVid = extVtx.eVid
brVtx = db.getVtx brVid
var okHike = Hike(root: hike.root, legs: hike.legs)
if not brVtx.isValid:
# Blind vertex, promote to leaf vertex.
#
# --(extVid)--> <extVtx> --(brVid)--> nil
#
# <-------- immutable -------------->
#
let vtx = VertexRef(
vType: Leaf,
lPfx: extVtx.ePfx & hike.tail,
lData: payload)
db.setVtxAndKey(hike.root, extVid, vtx)
okHike.legs[^1].wp.vtx = vtx
elif brVtx.vType != Branch:
return err(MergeBranchRootExpected)
else:
let
nibble = hike.tail[0].int8
linkID = brVtx.bVid[nibble]
#
# Required
#
# --(extVid)--> <extVtx> --(brVid)--> <brVtx>[nibble] --(linkID)--> nil
#
# <-------- immutable --------------> <-------- mutable ----------> ..
#
if linkID.isValid:
return err(MergeRootBranchLinkBusy)
# Clear Merkle hashes (aka hash keys) unless proof mode
if db.pPrf.len == 0:
db.clearMerkleKeys(hike, brVid)
elif brVid in db.pPrf:
return err(MergeBranchProofModeLock)
let
vid = db.vidFetch(pristine = true)
vtx = VertexRef(
vType: Leaf,
lPfx: hike.tail.slice(1),
lData: payload)
brVtx.bVid[nibble] = vid
db.setVtxAndKey(hike.root, brVid, brVtx)
db.setVtxAndKey(hike.root, vid, vtx)
okHike.legs.add Leg(wp: VidVtxPair(vtx: brVtx, vid: brVid), nibble: nibble)
okHike.legs.add Leg(wp: VidVtxPair(vtx: vtx, vid: vid), nibble: -1)
ok okHike
proc topIsEmptyAddLeaf(
db: AristoDbRef; # Database, top layer
hike: Hike; # No path legs
rootVtx: VertexRef; # Root vertex
payload: PayloadRef; # Leaf data payload
): Result[Hike,AristoError] =
## Append a `Leaf` vertex derived from the argument `payload` after the
## argument vertex `rootVtx` and append both the empty arguent `hike`.
if rootVtx.vType == Branch:
let nibble = hike.tail[0].int8
if rootVtx.bVid[nibble].isValid:
return err(MergeRootBranchLinkBusy)
# Clear Merkle hashes (aka hash keys) unless proof mode
if db.pPrf.len == 0:
db.clearMerkleKeys(hike, hike.root)
elif hike.root in db.pPrf:
return err(MergeBranchProofModeLock)
let
leafVid = db.vidFetch(pristine = true)
leafVtx = VertexRef(
vType: Leaf,
lPfx: hike.tail.slice(1),
lData: payload)
rootVtx.bVid[nibble] = leafVid
db.setVtxAndKey(hike.root, hike.root, rootVtx)
db.setVtxAndKey(hike.root, leafVid, leafVtx)
return ok Hike(
root: hike.root,
legs: @[Leg(wp: VidVtxPair(vtx: rootVtx, vid: hike.root), nibble: nibble),
Leg(wp: VidVtxPair(vtx: leafVtx, vid: leafVid), nibble: -1)])
db.insertBranch(hike, hike.root, rootVtx, payload)
proc updatePayload(
db: AristoDbRef; # Database, top layer
hike: Hike; # No path legs
leafTie: LeafTie; # Leaf item to add to the database
payload: PayloadRef; # Payload value
): Result[Hike,AristoError] =
## Update leaf vertex if payloads differ
let leafLeg = hike.legs[^1]
# Update payloads if they differ
if leafLeg.wp.vtx.lData != payload:
# Update vertex and hike
let
vid = leafLeg.wp.vid
vtx = VertexRef(
vType: Leaf,
lPfx: leafLeg.wp.vtx.lPfx,
lData: payload)
var hike = hike
hike.legs[^1].wp.vtx = vtx
# Modify top level cache
db.setVtxAndKey(hike.root, vid, vtx)
db.clearMerkleKeys(hike, vid)
ok hike
elif db.layersGetVtx(leafLeg.wp.vid).isErr:
err(MergeLeafPathOnBackendAlready)
else:
err(MergeLeafPathCachedAlready)
# ------------------------------------------------------------------------------
# Private functions: add Merkle proof node
# ------------------------------------------------------------------------------
proc mergeNodeImpl(
db: AristoDbRef; # Database, top layer
hashKey: HashKey; # Merkel hash of node (or so)
node: NodeRef; # Node derived from RLP representation
rootVid: VertexID; # Current sub-trie
): Result[void,AristoError] =
## The function merges the argument hash key `lid` as expanded from the
## node RLP representation into the `Aristo Trie` database. The vertex is
## split off from the node and stored separately. So are the Merkle hashes.
## The vertex is labelled `locked`.
##
## The `node` argument is *not* checked, whether the vertex IDs have been
## allocated, already. If the node comes straight from the `decode()` RLP
## decoder as expected, these vertex IDs will be all zero.
##
## This function expects that the parent for the argument `node` has already
## been installed.
##
## Caveat:
## Proof of concept, not in production yet.
##
# Check for error after RLP decoding
doAssert node.error == AristoError(0)
# Verify arguments
if not rootVid.isValid:
return err(MergeRootKeyInvalid)
if not hashKey.isValid:
return err(MergeHashKeyInvalid)
# Make sure that the `vid<->key` reverse mapping is updated.
let vid = db.layerGetProofVidOrVoid hashKey
if not vid.isValid:
return err(MergeRevVidMustHaveBeenCached)
# Use the vertex ID `vid` to be populated by the argument root node
let key = db.layersGetKeyOrVoid vid
if key.isValid and key != hashKey:
return err(MergeHashKeyDiffersFromCached)
# Set up vertex.
let (vtx, newVtxFromNode) = block:
let vty = db.getVtx vid
if vty.isValid:
(vty, false)
else:
(node.to(VertexRef), true)
# The `vertexID <-> hashKey` mappings need to be set up now (if any)
case node.vType:
of Leaf:
discard
of Extension:
if node.key[0].isValid:
let eKey = node.key[0]
if newVtxFromNode:
# Brand new reverse lookup link for this vertex
vtx.eVid = db.vidFetch
db.layersPutProof(vtx.eVid, eKey)
elif not vtx.eVid.isValid:
return err(MergeNodeVtxDiffersFromExisting)
db.layersPutProof(vtx.eVid, eKey)
of Branch:
for n in 0..15:
if node.key[n].isValid:
let bKey = node.key[n]
if newVtxFromNode:
# Brand new reverse lookup link for this vertex
vtx.bVid[n] = db.vidFetch
db.layersPutProof(vtx.bVid[n], bKey)
elif not vtx.bVid[n].isValid:
return err(MergeNodeVtxDiffersFromExisting)
db.layersPutProof(vtx.bVid[n], bKey)
# Store and lock vertex
db.layersPutProof(vid, key, vtx)
ok()
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc mergePayload*(
db: AristoDbRef; # Database, top layer
leafTie: LeafTie; # Leaf item to add to the database
payload: PayloadRef; # Payload value
accPath: PathID; # Needed for accounts payload
): Result[Hike,AristoError] =
## Merge the argument `leafTie` key-value-pair into the top level vertex
## table of the database `db`. The field `path` of the `leafTie` argument is
## used to index the leaf vertex on the `Patricia Trie`. The field `payload`
## is stored with the leaf vertex in the database unless the leaf vertex
## exists already.
##
## For a `payload.root` with `VertexID` greater than `LEAST_FREE_VID`, the
## sub-tree generated by `payload.root` is considered a storage trie linked
## to an account leaf referred to by a valid `accPath` (i.e. different from
## `VOID_PATH_ID`.) In that case, an account must exists. If there is payload
## of type `AccountData`, its `storageID` field must be unset or equal to the
## `payload.root` vertex ID.
##
if LEAST_FREE_VID <= leafTie.root.distinctBase:
? db.registerAccount(leafTie.root, accPath)
elif not leafTie.root.isValid:
return err(MergeRootMissing)
let hike = leafTie.hikeUp(db).to(Hike)
var okHike: Hike
if 0 < hike.legs.len:
case hike.legs[^1].wp.vtx.vType:
of Branch:
okHike = ? db.topIsBranchAddLeaf(hike, payload)
of Leaf:
if 0 < hike.tail.len: # `Leaf` vertex problem?
return err(MergeLeafGarbledHike)
okHike = ? db.updatePayload(hike, leafTie, payload)
of Extension:
okHike = ? db.topIsExtAddLeaf(hike, payload)
else:
# Empty hike
let rootVtx = db.getVtx hike.root
if rootVtx.isValid:
okHike = ? db.topIsEmptyAddLeaf(hike,rootVtx, payload)
else:
# Bootstrap for existing root ID
let wp = VidVtxPair(
vid: hike.root,
vtx: VertexRef(
vType: Leaf,
lPfx: leafTie.path.to(NibblesSeq),
lData: payload))
db.setVtxAndKey(hike.root, wp.vid, wp.vtx)
okHike = Hike(root: wp.vid, legs: @[Leg(wp: wp, nibble: -1)])
# Double check the result until the code is more reliable
block:
let rc = okHike.to(NibblesSeq).pathToTag
if rc.isErr or rc.value != leafTie.path:
return err(MergeAssemblyFailed) # Ooops
ok okHike
proc mergePayload*(
db: AristoDbRef; # Database, top layer
root: VertexID; # MPT state root
path: openArray[byte]; # Even nibbled byte path
payload: PayloadRef; # Payload value
accPath = VOID_PATH_ID; # Needed for accounts payload
): Result[bool,AristoError] =
## Variant of `merge()` for `(root,path)` arguments instead of a `LeafTie`
## object.
let lty = LeafTie(root: root, path: ? path.pathToTag)
db.mergePayload(lty, payload, accPath).to(typeof result)
proc merge*(
db: AristoDbRef; # Database, top layer
root: VertexID; # MPT state root
path: openArray[byte]; # Leaf item to add to the database
data: openArray[byte]; # Raw data payload value
accPath: PathID; # Needed for accounts payload
): Result[bool,AristoError] =
## Variant of `merge()` for `(root,path)` arguments instead of a `LeafTie`.
## The argument `data` is stored as-is as a `RawData` payload value.
let pyl = PayloadRef(pType: RawData, rawBlob: @data)
db.mergePayload(root, path, pyl, accPath)
proc mergeAccount*(
db: AristoDbRef; # Database, top layer
path: openArray[byte]; # Leaf item to add to the database
data: openArray[byte]; # Raw data payload value
): Result[bool,AristoError] =
## Variant of `merge()` for `(VertexID(1),path)` arguments instead of a
## `LeafTie`. The argument `data` is stored as-is as a `RawData` payload
## value.
let pyl = PayloadRef(pType: RawData, rawBlob: @data)
db.mergePayload(VertexID(1), path, pyl, VOID_PATH_ID)
proc mergeLeaf*(
db: AristoDbRef; # Database, top layer
leaf: LeafTiePayload; # Leaf item to add to the database
accPath = VOID_PATH_ID; # Needed for accounts payload
): Result[bool,AristoError] =
## Variant of `merge()`. This function will not indicate if the leaf
## was cached, already.
db.mergePayload(leaf.leafTie, leaf.payload, accPath).to(typeof result)
# ---------------------
proc merge*(
db: AristoDbRef; # Database, top layer
proof: openArray[SnapProof]; # RLP encoded node records
rootVid: VertexID; # Current sub-trie
): Result[int, AristoError]
{.gcsafe, raises: [RlpError].} =
## The function merges the argument `proof` list of RLP encoded node records
## into the `Aristo Trie` database. This function is intended to be used with
## the proof nodes as returened by `snap/1` messages.
##
## Caveat:
## Proof of concept, not in production yet.
##
proc update(
seen: var Table[HashKey,NodeRef];
todo: var KeyedQueueNV[NodeRef];
key: HashKey;
) {.gcsafe, raises: [RlpError].} =
## Check for embedded nodes, i.e. fully encoded node instead of a hash
if key.isValid and key.len < 32:
let lid = @key.digestTo(HashKey)
if not seen.hasKey lid:
let node = @key.decode(NodeRef)
discard todo.append node
seen[lid] = node
if not rootVid.isValid:
return err(MergeRootVidInvalid)
let rootKey = db.getKey rootVid
if not rootKey.isValid:
return err(MergeRootKeyInvalid)
# Make sure that the reverse lookup for the root vertex key is available.
if not db.layerGetProofVidOrVoid(rootKey).isValid:
return err(MergeProofInitMissing)
# Expand and collect hash keys and nodes
var nodeTab: Table[HashKey,NodeRef]
for w in proof:
let
key = w.Blob.digestTo(HashKey)
node = rlp.decode(w.Blob,NodeRef)
if node.error != AristoError(0):
return err(node.error)
nodeTab[key] = node
# Check for embedded nodes, i.e. fully encoded node instead of a hash
var embNodes: KeyedQueueNV[NodeRef]
discard embNodes.append node
while true:
let node = embNodes.shift.valueOr: break
case node.vType:
of Leaf:
discard
of Branch:
for n in 0 .. 15:
nodeTab.update(embNodes, node.key[n])
of Extension:
nodeTab.update(embNodes, node.key[0])
# Create a table with back links
var
backLink: Table[HashKey,HashKey]
blindNodes: HashSet[HashKey]
for (key,node) in nodeTab.pairs:
case node.vType:
of Leaf:
blindNodes.incl key
of Extension:
if nodeTab.hasKey node.key[0]:
backLink[node.key[0]] = key
else:
blindNodes.incl key
of Branch:
var isBlind = true
for n in 0 .. 15:
if nodeTab.hasKey node.key[n]:
isBlind = false
backLink[node.key[n]] = key
if isBlind:
blindNodes.incl key
# Run over blind nodes and build chains from a blind/bottom level node up
# to the root node. Select only chains that end up at the pre-defined root
# node.
var chains: seq[seq[HashKey]]
for w in blindNodes:
# Build a chain of nodes up to the root node
var
chain: seq[HashKey]
nodeKey = w
while nodeKey.isValid and nodeTab.hasKey nodeKey:
chain.add nodeKey
nodeKey = backLink.getOrVoid nodeKey
if 0 < chain.len and chain[^1] == rootKey:
chains.add chain
# Process over chains in reverse mode starting with the root node. This
# allows the algorithm to find existing nodes on the backend.
var
seen: HashSet[HashKey]
merged = 0
# Process the root ID which is common to all chains
for chain in chains:
for key in chain.reversed:
if key notin seen:
seen.incl key
db.mergeNodeImpl(key, nodeTab.getOrVoid key, rootVid).isOkOr:
return err(error)
merged.inc
ok merged
proc merge*(
db: AristoDbRef; # Database, top layer
rootHash: Hash256; # Merkle hash for root
rootVid = VertexID(0); # Optionally, force root vertex ID
): Result[VertexID,AristoError] =
## Set up a `rootKey` associated with a vertex ID for use with proof nodes.
##
## If argument `rootVid` is unset then a new dybamic root vertex (i.e.
## the ID will be at least `LEAST_FREE_VID`) will be installed.
##
## Otherwise, if the argument `rootVid` is set then a sub-trie with root
## `rootVid` is checked for. An error is returned if it is set up already
## with a different `rootHash`.
##
## Upon successful return, the vertex ID assigned to the root key is returned.
##
## Caveat:
## Proof of concept, not in production yet.
##
let rootKey = rootHash.to(HashKey)
if rootVid.isValid:
let key = db.getKey rootVid
if key.isValid:
if rootKey.isValid and key != rootKey:
# Cannot use installed root key differing from hash argument
return err(MergeRootKeyDiffersForVid)
# Confirm root ID and key for proof nodes processing
db.layersPutProof(rootVid, key) # note that `rootKey` might be void
return ok rootVid
if not rootHash.isValid:
return err(MergeRootArgsIncomplete)
if db.getVtx(rootVid).isValid:
# Cannot use verify root key for existing root vertex
return err(MergeRootKeyMissing)
# Confirm root ID and hash key for proof nodes processing
db.layersPutProof(rootVid, rootKey)
return ok rootVid
if not rootHash.isValid:
return err(MergeRootArgsIncomplete)
# Now there is no root vertex ID, only the hash argument.
# So Create and assign a new root key.
let vid = db.vidFetch
db.layersPutProof(vid, rootKey)
return ok vid
proc merge*(
db: AristoDbRef; # Database, top layer
rootVid: VertexID; # Root ID
): Result[VertexID,AristoError] =
## Variant of `merge()` for missing `rootHash`
db.merge(EMPTY_ROOT_HASH, rootVid)
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------