nimbus-eth1/nimbus/sync/snap/worker/db/hexary_interpolate.nim

454 lines
14 KiB
Nim

# nimbus-eth1
# Copyright (c) 2021 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.
## For a given path, sdd missing nodes to a hexary trie.
##
## This module function is temporary and proof-of-concept. for production
## purposes, it should be replaced by the new facility of the upcoming
## re-factored database layer.
import
std/[sequtils, strutils, tables],
eth/[common/eth_types, trie/nibbles],
stew/results,
../../range_desc,
"."/[hexary_defs, hexary_desc, hexary_paths]
{.push raises: [Defect].}
const
RepairTreeDebugging = false
type
RPathXStep = object
## Extended `RPathStep` needed for `NodeKey` assignmant
pos*: int ## Some position into `seq[RPathStep]`
step*: RPathStep ## Modified copy of an `RPathStep`
canLock*: bool ## Can set `Locked` state
# ------------------------------------------------------------------------------
# Private debugging helpers
# ------------------------------------------------------------------------------
proc pp(w: RPathXStep; db: HexaryTreeDB): string =
let y = if w.canLock: "lockOk" else: "noLock"
"(" & $w.pos & "," & y & "," & w.step.pp(db) & ")"
proc pp(w: seq[RPathXStep]; db: HexaryTreeDB; indent = 4): string =
let pfx = "\n" & " ".repeat(indent)
w.mapIt(it.pp(db)).join(pfx)
# ------------------------------------------------------------------------------
# Private helpers
# ------------------------------------------------------------------------------
proc dup(node: RNodeRef): RNodeRef =
new result
result[] = node[]
# ------------------------------------------------------------------------------
# Private getters & setters
# ------------------------------------------------------------------------------
proc xPfx(node: RNodeRef): NibblesSeq =
case node.kind:
of Leaf:
return node.lPfx
of Extension:
return node.ePfx
of Branch:
doAssert node.kind != Branch # Ooops
proc `xPfx=`(node: RNodeRef, val: NibblesSeq) =
case node.kind:
of Leaf:
node.lPfx = val
of Extension:
node.ePfx = val
of Branch:
doAssert node.kind != Branch # Ooops
proc xData(node: RNodeRef): Blob =
case node.kind:
of Branch:
return node.bData
of Leaf:
return node.lData
of Extension:
doAssert node.kind != Extension # Ooops
proc `xData=`(node: RNodeRef; val: Blob) =
case node.kind:
of Branch:
node.bData = val
of Leaf:
node.lData = val
of Extension:
doAssert node.kind != Extension # Ooops
# ------------------------------------------------------------------------------
# Private functions, repair tree action helpers
# ------------------------------------------------------------------------------
proc rTreeExtendLeaf(
db: var HexaryTreeDB;
rPath: RPath;
key: RepairKey
): RPath =
## Append a `Leaf` node to a `Branch` node (see `rTreeExtend()`.)
if 0 < rPath.tail.len:
let
nibble = rPath.path[^1].nibble
leaf = RNodeRef(
state: Mutable,
kind: Leaf,
lPfx: rPath.tail)
db.tab[key] = leaf
if not key.isNodeKey:
rPath.path[^1].node.bLink[nibble] = key
return RPath(
path: rPath.path & RPathStep(key: key, node: leaf, nibble: -1),
tail: EmptyNibbleRange)
proc rTreeExtendLeaf(
db: var HexaryTreeDB;
rPath: RPath;
key: RepairKey;
node: RNodeRef
): RPath =
## Register `node` and append/link a `Leaf` node to a `Branch` node (see
## `rTreeExtend()`.)
if 1 < rPath.tail.len and node.state == Mutable:
let
nibble = rPath.tail[0].int8
xStep = RPathStep(key: key, node: node, nibble: nibble)
xPath = RPath(path: rPath.path & xStep, tail: rPath.tail.slice(1))
return db.rTreeExtendLeaf(xPath, db.newRepairKey())
proc rTreeSplitNode(
db: var HexaryTreeDB;
rPath: RPath;
key: RepairKey;
node: RNodeRef
): RPath =
## Replace `Leaf` or `Extension` node in tuple `(key,node)` by parts (see
## `rTreeExtend()`):
##
## left(Extension) -> middle(Branch) -> right(Extension or Leaf)
## ^ ^
## | |
## added-to-path added-to-path
##
## where either `left()` or `right()` extensions might be missing.
##
let
nibbles = node.xPfx
lLen = rPath.tail.sharedPrefixLen(nibbles)
if nibbles.len == 0 or rPath.tail.len <= lLen:
return # Ooops (^^^^^ otherwise `rPath` was not the longest)
var
mKey = key
let
mNibble = nibbles[lLen] # exists as `lLen < tail.len`
rPfx = nibbles.slice(lLen + 1) # might be empty OK
result = rPath
# Insert node (if any): left(Extension)
if 0 < lLen:
let lNode = RNodeRef(
state: Mutable,
kind: Extension,
ePfx: result.tail.slice(0,lLen),
eLink: db.newRepairKey())
db.tab[key] = lNode
result.path.add RPathStep(key: key, node: lNode, nibble: -1)
result.tail = result.tail.slice(lLen)
mKey = lNode.eLink
# Insert node: middle(Branch)
let mNode = RNodeRef(
state: Mutable,
kind: Branch)
db.tab[mKey] = mNode
result.path.add RPathStep(key: mKey, node: mNode, nibble: -1) # no nibble yet
# Insert node (if any): right(Extension) -- not to be registered in `rPath`
if 0 < rPfx.len:
let rKey = db.newRepairKey()
# Re-use argument node
mNode.bLink[mNibble] = rKey
db.tab[rKey] = node
node.xPfx = rPfx
# Otherwise merge argument node
elif node.kind == Extension:
mNode.bLink[mNibble] = node.eLink
else:
# Oops, does it make sense, at all?
mNode.bData = node.lData
# ------------------------------------------------------------------------------
# Private functions, repair tree actions
# ------------------------------------------------------------------------------
proc rTreeInterpolate(
rPath: RPath;
db: var HexaryTreeDB
): RPath
{.gcsafe, raises: [Defect,KeyError]} =
## Extend path, add missing nodes to tree. The last node added will be
## a `Leaf` node if this function succeeds.
##
## The function assumed that the `RPath` argument is the longest possible
## as just constructed by `rTreeFollow()`
if 0 < rPath.path.len and 0 < rPath.tail.len:
let step = rPath.path[^1]
case step.node.kind:
of Branch:
# Now, the slot must not be empty. An empty slot would lead to a
# rejection of this record as last valid step, contrary to the
# assumption `path` is the longest one.
if step.nibble < 0:
return # sanitary check failed
let key = step.node.bLink[step.nibble]
if key.isZero:
return # sanitary check failed
# Case: unused slot => add leaf record
if not db.tab.hasKey(key):
return db.rTreeExtendLeaf(rPath, key)
# So a `child` node exits but it is something that could not be used to
# extend the argument `path` which is assumed the longest possible one.
let child = db.tab[key]
case child.kind:
of Branch:
# So a `Leaf` node can be linked into the `child` branch
return db.rTreeExtendLeaf(rPath, key, child)
# Need to split the right `grandChild` in `child -> grandChild`
# into parts:
#
# left(Extension) -> middle(Branch)
# | |
# | +-----> right(Extension or Leaf) ...
# +---------> new Leaf record
#
# where either `left()` or `right()` extensions might be missing
of Extension, Leaf:
var xPath = db.rTreeSplitNode(rPath, key, child)
if 0 < xPath.path.len:
# Append `Leaf` node
xPath.path[^1].nibble = xPath.tail[0].int8
xPath.tail = xPath.tail.slice(1)
return db.rTreeExtendLeaf(xPath, db.newRepairKey())
of Leaf:
return # Oops
of Extension:
let key = step.node.eLink
var child: RNodeRef
if db.tab.hasKey(key):
child = db.tab[key]
# `Extension` can only be followed by a `Branch` node
if child.kind != Branch:
return
else:
# Case: unused slot => add `Branch` and `Leaf` record
child = RNodeRef(
state: Mutable,
kind: Branch)
db.tab[key] = child
# So a `Leaf` node can be linked into the `child` branch
return db.rTreeExtendLeaf(rPath, key, child)
proc rTreeInterpolate(
rPath: RPath;
db: var HexaryTreeDB;
payload: Blob
): RPath
{.gcsafe, raises: [Defect,KeyError]} =
## Variant of `rTreeExtend()` which completes a `Leaf` record.
result = rPath.rTreeInterpolate(db)
if 0 < result.path.len and result.tail.len == 0:
let node = result.path[^1].node
if node.kind != Extension and node.state == Mutable:
node.xData = payload
proc rTreeUpdateKeys(
rPath: RPath;
db: var HexaryTreeDB
): Result[void,int]
{.gcsafe, raises: [Defect,KeyError]} =
## The argument `rPath` is assumed to organise database nodes as
##
## root -> ... -> () -> () -> ... -> () -> () ...
## |-------------| |------------| |------
## static nodes locked nodes mutable nodes
##
## Where
## * Static nodes are read-only nodes provided by the proof database
## * Locked nodes are added read-only nodes that satisfy the proof condition
## * Mutable nodes are incomplete nodes
##
## Then update nodes from the right end and set all the mutable nodes
## locked if possible.
var
rTop = rPath.path.len
stack: seq[RPathXStep]
if 0 < rTop and
rPath.path[^1].node.state == Mutable and
rPath.path[0].node.state != Mutable:
# Set `Leaf` entry
let leafNode = rPath.path[^1].node.dup
stack.add RPathXStep(
pos: rTop - 1,
canLock: true,
step: RPathStep(
node: leafNode,
key: leafNode.convertTo(Blob).digestTo(NodeKey).to(RepairKey),
nibble: -1))
while true:
rTop.dec
# Update parent node (note that `2 <= rPath.path.len`)
let
thisKey = stack[^1].step.key
preStep = rPath.path[rTop-1]
preNibble = preStep.nibble
# End reached
if preStep.node.state != Mutable:
# Verify the tail matches
var key = RepairKey.default
case preStep.node.kind:
of Branch:
key = preStep.node.bLink[preNibble]
of Extension:
key = preStep.node.eLink
of Leaf:
discard
if key != thisKey:
return err(rTop-1)
when RepairTreeDebugging:
echo "*** rTreeUpdateKeys",
" rPath\n ", rPath.pp(ps),
"\n stack\n ", stack.pp(ps)
# Ok, replace database records by stack entries
var lockOk = true
for n in countDown(stack.len-1,0):
let item = stack[n]
db.tab.del(rPath.path[item.pos].key)
db.tab[item.step.key] = item.step.node
if lockOk:
if item.canLock:
item.step.node.state = Locked
else:
lockOk = false
if not lockOk:
return err(rTop-1) # repeat
break # Done ok()
stack.add RPathXStep(
pos: rTop - 1,
step: RPathStep(
node: preStep.node.dup, # (!)
nibble: preNibble,
key: preStep.key))
case stack[^1].step.node.kind:
of Branch:
stack[^1].step.node.bLink[preNibble] = thisKey
# Check whether all keys are proper, non-temporary keys
stack[^1].canLock = true
for n in 0 ..< 16:
if not stack[^1].step.node.bLink[n].isNodeKey:
stack[^1].canLock = false
break
of Extension:
stack[^1].step.node.eLink = thisKey
stack[^1].canLock = thisKey.isNodeKey
of Leaf:
return err(rTop-1)
# Must not overwrite a non-temprary key
if stack[^1].canLock:
stack[^1].step.key =
stack[^1].step.node.convertTo(Blob).digestTo(NodeKey).to(RepairKey)
ok()
# ------------------------------------------------------------------------------
# Public fuctions
# ------------------------------------------------------------------------------
proc hexary_interpolate*(
db: var HexaryTreeDB
): Result[void,HexaryDbError]
{.gcsafe, raises: [Defect,KeyError]} =
## Verifiy accounts by interpolating the collected accounts on the hexary
## trie of the repair database. If all accounts can be represented in the
## hexary trie, they are vonsidered validated.
##
# Walk top down and insert/complete missing account access nodes
for n in countDown(db.acc.len-1,0):
let acc = db.acc[n]
if acc.payload.len != 0:
let rPath = acc.pathTag.hexaryPath(db)
var repairKey = acc.nodeKey
if repairKey.isZero and 0 < rPath.path.len and rPath.tail.len == 0:
repairKey = rPath.path[^1].key
db.acc[n].nodeKey = repairKey
if repairKey.isZero:
let
update = rPath.rTreeInterpolate(db, acc.payload)
final = acc.pathTag.hexaryPath(db)
if update != final:
return err(AccountRepairBlocked)
db.acc[n].nodeKey = rPath.path[^1].key
# Replace temporary repair keys by proper hash based node keys.
var reVisit: seq[NodeTag]
for n in countDown(db.acc.len-1,0):
let acc = db.acc[n]
if not acc.nodeKey.isZero:
let rPath = acc.pathTag.hexaryPath(db)
if rPath.path[^1].node.state == Mutable:
let rc = rPath.rTreeUpdateKeys(db)
if rc.isErr:
reVisit.add acc.pathTag
while 0 < reVisit.len:
var again: seq[NodeTag]
for nodeTag in reVisit:
let rc = nodeTag.hexaryPath(db).rTreeUpdateKeys(db)
if rc.isErr:
again.add nodeTag
if reVisit.len <= again.len:
return err(BoundaryProofFailed)
reVisit = again
ok()
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------