735 lines
23 KiB
Nim
735 lines
23 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.
|
|
|
|
|
|
import
|
|
std/tables,
|
|
eth/[common, trie/nibbles],
|
|
stew/results,
|
|
../../range_desc,
|
|
"."/[hexary_desc, hexary_error, hexary_paths]
|
|
|
|
{.push raises: [Defect].}
|
|
|
|
proc hexaryNearbyRight*(path: RPath; db: HexaryTreeDbRef;
|
|
): Result[RPath,HexaryError] {.gcsafe, raises: [Defect,KeyError]}
|
|
|
|
proc hexaryNearbyRight*(path: XPath; getFn: HexaryGetFn;
|
|
): Result[XPath,HexaryError] {.gcsafe, raises: [Defect,RlpError]}
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Private helpers
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc toBranchNode(
|
|
rlp: Rlp
|
|
): XNodeObj
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
var rlp = rlp
|
|
XNodeObj(kind: Branch, bLink: rlp.read(array[17,Blob]))
|
|
|
|
proc toLeafNode(
|
|
rlp: Rlp;
|
|
pSegm: NibblesSeq
|
|
): XNodeObj
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
XNodeObj(kind: Leaf, lPfx: pSegm, lData: rlp.listElem(1).toBytes)
|
|
|
|
proc toExtensionNode(
|
|
rlp: Rlp;
|
|
pSegm: NibblesSeq
|
|
): XNodeObj
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
XNodeObj(kind: Extension, ePfx: pSegm, eLink: rlp.listElem(1).toBytes)
|
|
|
|
proc `<=`(a, b: NibblesSeq): bool =
|
|
## Compare nibbles, different lengths are padded to the right with zeros
|
|
let abMin = min(a.len, b.len)
|
|
for n in 0 ..< abMin:
|
|
if a[n] < b[n]:
|
|
return true
|
|
if b[n] < a[n]:
|
|
return false
|
|
# otherwise a[n] == b[n]
|
|
|
|
# Assuming zero for missing entries
|
|
if b.len < a.len:
|
|
for n in abMin + 1 ..< a.len:
|
|
if 0 < a[n]:
|
|
return false
|
|
true
|
|
|
|
proc `<`(a, b: NibblesSeq): bool =
|
|
not (b <= a)
|
|
|
|
|
|
template noKeyErrorOops(info: static[string]; code: untyped) =
|
|
try:
|
|
code
|
|
except KeyError as e:
|
|
raiseAssert "Impossible KeyError (" & info & "): " & e.msg
|
|
|
|
template noRlpErrorOops(info: static[string]; code: untyped) =
|
|
try:
|
|
code
|
|
except RlpError as e:
|
|
raiseAssert "Impossible RlpError (" & info & "): " & e.msg
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Private functions, wrappers
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc hexaryNearbyRightImpl(
|
|
baseTag: NodeTag; ## Some node
|
|
rootKey: NodeKey; ## State root
|
|
db: HexaryTreeDbRef|HexaryGetFn; ## Database abstraction
|
|
): Result[NodeTag,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError,RlpError]} =
|
|
## Wrapper
|
|
let path = block:
|
|
let rc = baseTag.hexaryPath(rootKey, db).hexaryNearbyRight(db)
|
|
if rc.isErr:
|
|
return err(rc.error)
|
|
rc.value
|
|
|
|
if 0 < path.path.len and path.path[^1].node.kind == Leaf:
|
|
let nibbles = path.getNibbles
|
|
if nibbles.len == 64:
|
|
return ok(nibbles.getBytes.convertTo(NodeTag))
|
|
|
|
err(NearbyLeafExpected)
|
|
|
|
proc hexaryNearbyLeftImpl(
|
|
baseTag: NodeTag; ## Some node
|
|
rootKey: NodeKey; ## State root
|
|
db: HexaryTreeDbRef|HexaryGetFn; ## Database abstraction
|
|
): Result[NodeTag,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError,RlpError]} =
|
|
## Wrapper
|
|
let path = block:
|
|
let rc = baseTag.hexaryPath(rootKey, db).hexaryNearbyLeft(db)
|
|
if rc.isErr:
|
|
return err(rc.error)
|
|
rc.value
|
|
|
|
if 0 < path.path.len and path.path[^1].node.kind == Leaf:
|
|
let nibbles = path.getNibbles
|
|
if nibbles.len == 64:
|
|
return ok(nibbles.getBytes.convertTo(NodeTag))
|
|
|
|
err(NearbyLeafExpected)
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Private functions
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc completeLeast(
|
|
path: RPath;
|
|
key: RepairKey;
|
|
db: HexaryTreeDbRef;
|
|
pathLenMax = 64;
|
|
): Result[RPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError].} =
|
|
## Extend path using least nodes without recursion.
|
|
var rPath = RPath(path: path.path)
|
|
|
|
if not db.tab.hasKey(key):
|
|
return err(NearbyDanglingLink)
|
|
var
|
|
key = key
|
|
node = db.tab[key]
|
|
|
|
while rPath.path.len < pathLenMax:
|
|
case node.kind:
|
|
of Leaf:
|
|
rPath.path.add RPathStep(key: key, node: node, nibble: -1)
|
|
return ok(rPath) # done
|
|
|
|
of Extension:
|
|
block useExtensionLink:
|
|
let newKey = node.eLink
|
|
if not newkey.isZero:
|
|
if db.tab.hasKey(newKey):
|
|
rPath.path.add RPathStep(key: key, node: node, nibble: -1)
|
|
key = newKey
|
|
node = db.tab[key]
|
|
break useExtensionLink
|
|
return err(NearbyExtensionError) # Oops, no way
|
|
|
|
of Branch:
|
|
block findBranchLink:
|
|
for inx in 0 .. 15:
|
|
let newKey = node.bLink[inx]
|
|
if not newKey.isZero:
|
|
if db.tab.hasKey(newKey):
|
|
rPath.path.add RPathStep(key: key, node: node, nibble: inx.int8)
|
|
key = newKey
|
|
node = db.tab[key]
|
|
break findBranchLink
|
|
return err(NearbyBranchError) # Oops, no way
|
|
|
|
err(NearbyNestingTooDeep)
|
|
|
|
|
|
proc completeLeast(
|
|
path: XPath;
|
|
key: Blob;
|
|
getFn: HexaryGetFn;
|
|
pathLenMax = 64;
|
|
): Result[XPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,RlpError].} =
|
|
## Variant of `completeLeast()` for persistent database
|
|
var xPath = XPath(path: path.path)
|
|
|
|
if key.getFn().len == 0:
|
|
return err(NearbyDanglingLink)
|
|
var
|
|
key = key
|
|
nodeRlp = rlpFromBytes key.getFn()
|
|
|
|
while xPath.path.len < pathLenMax:
|
|
case nodeRlp.listLen:
|
|
of 2:
|
|
let (isLeaf,pathSegment) = hexPrefixDecode nodeRlp.listElem(0).toBytes
|
|
if isLeaf:
|
|
let node = nodeRlp.toLeafNode(pathSegment)
|
|
xPath.path.add XPathStep(key: key, node: node, nibble: -1)
|
|
return ok(xPath) # done
|
|
|
|
# Extension
|
|
block useExtensionLink:
|
|
let
|
|
node = nodeRlp.toExtensionNode(pathSegment)
|
|
newKey = node.eLink
|
|
if 0 < newKey.len:
|
|
let newNode = newKey.getFn()
|
|
if 0 < newNode.len:
|
|
xPath.path.add XPathStep(key: key, node: node, nibble: -1)
|
|
key = newKey
|
|
nodeRlp = rlpFromBytes newNode
|
|
break useExtensionLink
|
|
return err(NearbyExtensionError) # Oops, no way
|
|
|
|
of 17:
|
|
block findBranchLink:
|
|
let node = nodeRlp.toBranchNode()
|
|
for inx in 0 .. 15:
|
|
let newKey = node.bLink[inx]
|
|
if 0 < newKey.len:
|
|
let newNode = newKey.getFn()
|
|
if 0 < newNode.len:
|
|
xPath.path.add XPathStep(key: key, node: node, nibble: inx.int8)
|
|
key = newKey
|
|
nodeRlp = rlpFromBytes newNode
|
|
break findBranchLink
|
|
return err(NearbyBranchError) # Oops, no way
|
|
|
|
else:
|
|
return err(NearbyGarbledNode) # Oops, no way
|
|
|
|
err(NearbyNestingTooDeep)
|
|
|
|
|
|
proc completeMost(
|
|
path: RPath;
|
|
key: RepairKey;
|
|
db: HexaryTreeDbRef;
|
|
pathLenMax = 64;
|
|
): Result[RPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError].} =
|
|
## Extend path using max nodes without recursion.
|
|
var rPath = RPath(path: path.path)
|
|
|
|
if not db.tab.hasKey(key):
|
|
return err(NearbyDanglingLink)
|
|
var
|
|
key = key
|
|
node = db.tab[key]
|
|
|
|
while rPath.path.len < pathLenMax:
|
|
case node.kind:
|
|
of Leaf:
|
|
rPath.path.add RPathStep(key: key, node: node, nibble: -1)
|
|
return ok(rPath) # done
|
|
|
|
of Extension:
|
|
block useExtensionLink:
|
|
let newKey = node.eLink
|
|
if not newkey.isZero:
|
|
if db.tab.hasKey(newKey):
|
|
rPath.path.add RPathStep(key: key, node: node, nibble: -1)
|
|
key = newKey
|
|
node = db.tab[newKey]
|
|
break useExtensionLink
|
|
return err(NearbyExtensionError) # Oops, no way
|
|
|
|
of Branch:
|
|
block findBranchLink:
|
|
for inx in 15.countDown(0):
|
|
let newKey = node.bLink[inx]
|
|
if not newKey.isZero:
|
|
if db.tab.hasKey(newKey):
|
|
rPath.path.add RPathStep(key: key, node: node, nibble: inx.int8)
|
|
key = newKey
|
|
node = db.tab[key]
|
|
break findBranchLink
|
|
return err(NearbyBranchError) # Oops, no way
|
|
|
|
err(NearbyNestingTooDeep)
|
|
|
|
proc completeMost(
|
|
path: XPath;
|
|
key: Blob;
|
|
getFn: HexaryGetFn;
|
|
pathLenMax = 64;
|
|
): Result[XPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,RlpError].} =
|
|
## Variant of `completeLeast()` for persistent database
|
|
var xPath = XPath(path: path.path)
|
|
|
|
if key.getFn().len == 0:
|
|
return err(NearbyDanglingLink)
|
|
var
|
|
key = key
|
|
nodeRlp = rlpFromBytes key.getFn()
|
|
|
|
while xPath.path.len < pathLenMax:
|
|
case nodeRlp.listLen:
|
|
of 2:
|
|
let (isLeaf,pathSegment) = hexPrefixDecode nodeRlp.listElem(0).toBytes
|
|
if isLeaf:
|
|
let node = nodeRlp.toLeafNode(pathSegment)
|
|
xPath.path.add XPathStep(key: key, node: node, nibble: -1)
|
|
return ok(xPath) # done
|
|
|
|
# Extension
|
|
block useExtensionLink:
|
|
let
|
|
node = nodeRlp.toExtensionNode(pathSegment)
|
|
newKey = node.eLink
|
|
if 0 < newKey.len:
|
|
let newNode = newKey.getFn()
|
|
if 0 < newNode.len:
|
|
xPath.path.add XPathStep(key: key, node: node, nibble: -1)
|
|
key = newKey
|
|
nodeRlp = rlpFromBytes newNode
|
|
break useExtensionLink
|
|
return err(NearbyExtensionError) # Oops, no way
|
|
|
|
of 17:
|
|
block findBranchLink:
|
|
let node = nodeRlp.toBranchNode()
|
|
for inx in 15.countDown(0):
|
|
let newKey = node.bLink[inx]
|
|
if 0 < newKey.len:
|
|
let newNode = newKey.getFn()
|
|
if 0 < newNode.len:
|
|
xPath.path.add XPathStep(key: key, node: node, nibble: inx.int8)
|
|
key = newKey
|
|
nodeRlp = rlpFromBytes newNode
|
|
break findBranchLink
|
|
return err(NearbyBranchError) # Oops, no way
|
|
|
|
else:
|
|
return err(NearbyGarbledNode) # Oops, no way
|
|
|
|
err(NearbyNestingTooDeep)
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Public functions, left boundary proofs (moving right)
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc hexaryNearbyRight*(
|
|
path: RPath; ## Partially expanded path
|
|
db: HexaryTreeDbRef; ## Database
|
|
): Result[RPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError]} =
|
|
## Extends the maximally extended argument nodes `path` to the right (i.e.
|
|
## with non-decreasing path value). This is similar to the
|
|
## `hexary_path.next()` function, only that this algorithm does not
|
|
## backtrack if there are dangling links in between and rather returns
|
|
## an error.
|
|
##
|
|
## This code is intended to be used for verifying a left-bound proof to
|
|
## verify that there is no leaf node *right* of a boundary path value.
|
|
|
|
# Some easy cases
|
|
if path.path.len == 0:
|
|
return err(NearbyEmptyPath) # error
|
|
if path.path[^1].node.kind == Leaf:
|
|
return ok(path)
|
|
|
|
var rPath = path
|
|
while 0 < rPath.path.len:
|
|
let top = rPath.path[^1]
|
|
if top.node.kind != Branch or
|
|
top.nibble < 0 or
|
|
rPath.tail.len == 0:
|
|
return err(NearbyUnexpectedNode) # error
|
|
|
|
let topLink = top.node.bLink[top.nibble]
|
|
if topLink.isZero or not db.tab.hasKey(topLink):
|
|
return err(NearbyDanglingLink) # error
|
|
|
|
let nextNibble = rPath.tail[0].int8
|
|
if nextNibble < 15:
|
|
let
|
|
nextNode = db.tab[topLink]
|
|
rPathLen = rPath.path.len # in case of backtracking
|
|
rPathTail = rPath.tail
|
|
case nextNode.kind
|
|
of Leaf:
|
|
if rPath.tail <= nextNode.lPfx:
|
|
return rPath.completeLeast(topLink, db)
|
|
of Extension:
|
|
if rPath.tail <= nextNode.ePfx:
|
|
return rPath.completeLeast(topLink, db)
|
|
of Branch:
|
|
# Step down and complete with a branch link on the child node
|
|
rPath.path = rPath.path & RPathStep(
|
|
key: topLink,
|
|
node: nextNode,
|
|
nibble: nextNibble)
|
|
|
|
# Find the next item to the right of the new top entry
|
|
let step = rPath.path[^1]
|
|
for inx in (step.nibble + 1) .. 15:
|
|
let link = step.node.bLink[inx]
|
|
if not link.isZero:
|
|
rPath.path[^1].nibble = inx.int8
|
|
return rPath.completeLeast(link, db)
|
|
|
|
# Restore `rPath` and backtrack
|
|
rPath.path.setLen(rPathLen)
|
|
rPath.tail = rPathTail
|
|
|
|
# Pop `Branch` node on top and append nibble to `tail`
|
|
rPath.tail = @[top.nibble.byte].initNibbleRange.slice(1) & rPath.tail
|
|
rPath.path.setLen(rPath.path.len - 1)
|
|
|
|
# Pathological case: nfffff.. for n < f
|
|
var step = path.path[0]
|
|
for inx in (step.nibble + 1) .. 15:
|
|
let link = step.node.bLink[inx]
|
|
if not link.isZero:
|
|
step.nibble = inx.int8
|
|
rPath.path = @[step]
|
|
return rPath.completeLeast(link, db)
|
|
|
|
err(NearbyFailed) # error
|
|
|
|
|
|
proc hexaryNearbyRight*(
|
|
path: XPath; ## Partially expanded path
|
|
getFn: HexaryGetFn; ## Database abstraction
|
|
): Result[XPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
## Variant of `hexaryNearbyRight()` for persistant database
|
|
|
|
# Some easy cases
|
|
if path.path.len == 0:
|
|
return err(NearbyEmptyPath) # error
|
|
if path.path[^1].node.kind == Leaf:
|
|
return ok(path)
|
|
|
|
var xPath = path
|
|
while 0 < xPath.path.len:
|
|
let top = xPath.path[^1]
|
|
if top.node.kind != Branch or
|
|
top.nibble < 0 or
|
|
xPath.tail.len == 0:
|
|
return err(NearbyUnexpectedNode) # error
|
|
|
|
let topLink = top.node.bLink[top.nibble]
|
|
if topLink.len == 0 or topLink.getFn().len == 0:
|
|
return err(NearbyDanglingLink) # error
|
|
|
|
let nextNibble = xPath.tail[0].int8
|
|
if nextNibble < 15:
|
|
let
|
|
nextNodeRlp = rlpFromBytes topLink.getFn()
|
|
xPathLen = xPath.path.len # in case of backtracking
|
|
xPathTail = xPath.tail
|
|
case nextNodeRlp.listLen:
|
|
of 2:
|
|
if xPath.tail <= nextNodeRlp.listElem(0).toBytes.hexPrefixDecode[1]:
|
|
return xPath.completeLeast(topLink, getFn)
|
|
of 17:
|
|
# Step down and complete with a branch link on the child node
|
|
xPath.path = xPath.path & XPathStep(
|
|
key: topLink,
|
|
node: nextNodeRlp.toBranchNode,
|
|
nibble: nextNibble)
|
|
else:
|
|
return err(NearbyGarbledNode) # error
|
|
|
|
# Find the next item to the right of the new top entry
|
|
let step = xPath.path[^1]
|
|
for inx in (step.nibble + 1) .. 15:
|
|
let link = step.node.bLink[inx]
|
|
if 0 < link.len:
|
|
xPath.path[^1].nibble = inx.int8
|
|
return xPath.completeLeast(link, getFn)
|
|
|
|
# Restore `xPath` and backtrack
|
|
xPath.path.setLen(xPathLen)
|
|
xPath.tail = xPathTail
|
|
|
|
# Pop `Branch` node on top and append nibble to `tail`
|
|
xPath.tail = @[top.nibble.byte].initNibbleRange.slice(1) & xPath.tail
|
|
xPath.path.setLen(xPath.path.len - 1)
|
|
|
|
# Pathological case: nfffff.. for n < f
|
|
var step = path.path[0]
|
|
for inx in (step.nibble + 1) .. 15:
|
|
let link = step.node.bLink[inx]
|
|
if 0 < link.len:
|
|
step.nibble = inx.int8
|
|
xPath.path = @[step]
|
|
return xPath.completeLeast(link, getFn)
|
|
|
|
err(NearbyFailed) # error
|
|
|
|
|
|
proc hexaryNearbyRightMissing*(
|
|
path: RPath;
|
|
db: HexaryTreeDbRef;
|
|
): bool
|
|
{.gcsafe, raises: [Defect,KeyError]} =
|
|
## Returns `true` if the maximally extended argument nodes `path` is the
|
|
## rightmost on the hexary trie database. It verifies that there is no more
|
|
## leaf entry to the right of the argument `path`.
|
|
##
|
|
## This code is intended be used for verifying a left-bound proof.
|
|
if 0 < path.path.len and 0 < path.tail.len:
|
|
let top = path.path[^1]
|
|
if top.node.kind == Branch and 0 <= top.nibble:
|
|
|
|
let topLink = top.node.bLink[top.nibble]
|
|
if not topLink.isZero and db.tab.hasKey(topLink):
|
|
let
|
|
nextNibble = path.tail[0]
|
|
nextNode = db.tab[topLink]
|
|
|
|
case nextNode.kind
|
|
of Leaf:
|
|
return nextNode.lPfx < path.tail
|
|
|
|
of Extension:
|
|
return nextNode.ePfx < path.tail
|
|
|
|
of Branch:
|
|
# Step down and verify that there is no branch link
|
|
for inx in nextNibble .. 15:
|
|
if not nextNode.bLink[inx].isZero:
|
|
return false
|
|
return true
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Public functions, right boundary proofs (moving left)
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc hexaryNearbyLeft*(
|
|
path: RPath; ## Partially expanded path
|
|
db: HexaryTreeDbRef; ## Database
|
|
): Result[RPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError]} =
|
|
## Similar to `hexaryNearbyRight()`.
|
|
##
|
|
## This code is intended to be used for verifying a right-bound proof to
|
|
## verify that there is no leaf node *left* to a boundary path value.
|
|
|
|
# Some easy cases
|
|
if path.path.len == 0:
|
|
return err(NearbyEmptyPath) # error
|
|
if path.path[^1].node.kind == Leaf:
|
|
return ok(path)
|
|
|
|
var rPath = path
|
|
while 0 < rPath.path.len:
|
|
let top = rPath.path[^1]
|
|
if top.node.kind != Branch or
|
|
top.nibble < 0 or
|
|
rPath.tail.len == 0:
|
|
return err(NearbyUnexpectedNode) # error
|
|
|
|
let topLink = top.node.bLink[top.nibble]
|
|
if topLink.isZero or not db.tab.hasKey(topLink):
|
|
return err(NearbyDanglingLink) # error
|
|
|
|
let nextNibble = rPath.tail[0].int8
|
|
if 0 < nextNibble:
|
|
let
|
|
nextNode = db.tab[topLink]
|
|
rPathLen = rPath.path.len # in case of backtracking
|
|
rPathTail = rPath.tail
|
|
case nextNode.kind
|
|
of Leaf:
|
|
if nextNode.lPfx <= rPath.tail:
|
|
return rPath.completeMost(topLink, db)
|
|
of Extension:
|
|
if nextNode.ePfx <= rPath.tail:
|
|
return rPath.completeMost(topLink, db)
|
|
of Branch:
|
|
# Step down and complete with a branch link on the child node
|
|
rPath.path = rPath.path & RPathStep(
|
|
key: topLink,
|
|
node: nextNode,
|
|
nibble: nextNibble)
|
|
|
|
# Find the next item to the right of the new top entry
|
|
let step = rPath.path[^1]
|
|
for inx in (step.nibble - 1).countDown(0):
|
|
let link = step.node.bLink[inx]
|
|
if not link.isZero:
|
|
rPath.path[^1].nibble = inx.int8
|
|
return rPath.completeMost(link, db)
|
|
|
|
# Restore `rPath` and backtrack
|
|
rPath.path.setLen(rPathLen)
|
|
rPath.tail = rPathTail
|
|
|
|
# Pop `Branch` node on top and append nibble to `tail`
|
|
rPath.tail = @[top.nibble.byte].initNibbleRange.slice(1) & rPath.tail
|
|
rPath.path.setLen(rPath.path.len - 1)
|
|
|
|
# Pathological case: n0000.. for 0 < n
|
|
var step = path.path[0]
|
|
for inx in (step.nibble - 1).countDown(0):
|
|
let link = step.node.bLink[inx]
|
|
if not link.isZero:
|
|
step.nibble = inx.int8
|
|
rPath.path = @[step]
|
|
return rPath.completeMost(link, db)
|
|
|
|
err(NearbyFailed) # error
|
|
|
|
|
|
proc hexaryNearbyLeft*(
|
|
path: XPath; ## Partially expanded path
|
|
getFn: HexaryGetFn; ## Database abstraction
|
|
): Result[XPath,HexaryError]
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
## Variant of `hexaryNearbyLeft()` for persistant database
|
|
|
|
# Some easy cases
|
|
if path.path.len == 0:
|
|
return err(NearbyEmptyPath) # error
|
|
if path.path[^1].node.kind == Leaf:
|
|
return ok(path)
|
|
|
|
var xPath = path
|
|
while 0 < xPath.path.len:
|
|
let top = xPath.path[^1]
|
|
if top.node.kind != Branch or
|
|
top.nibble < 0 or
|
|
xPath.tail.len == 0:
|
|
return err(NearbyUnexpectedNode) # error
|
|
|
|
let topLink = top.node.bLink[top.nibble]
|
|
if topLink.len == 0 or topLink.getFn().len == 0:
|
|
return err(NearbyDanglingLink) # error
|
|
|
|
let nextNibble = xPath.tail[0].int8
|
|
if 0 < nextNibble:
|
|
let
|
|
nextNodeRlp = rlpFromBytes topLink.getFn()
|
|
xPathLen = xPath.path.len # in case of backtracking
|
|
xPathTail = xPath.tail
|
|
case nextNodeRlp.listLen:
|
|
of 2:
|
|
if nextNodeRlp.listElem(0).toBytes.hexPrefixDecode[1] <= xPath.tail:
|
|
return xPath.completeMost(topLink, getFn)
|
|
of 17:
|
|
# Step down and complete with a branch link on the child node
|
|
xPath.path = xPath.path & XPathStep(
|
|
key: topLink,
|
|
node: nextNodeRlp.toBranchNode,
|
|
nibble: nextNibble)
|
|
else:
|
|
return err(NearbyGarbledNode) # error
|
|
|
|
# Find the next item to the right of the new top entry
|
|
let step = xPath.path[^1]
|
|
for inx in (step.nibble - 1).countDown(0):
|
|
let link = step.node.bLink[inx]
|
|
if 0 < link.len:
|
|
xPath.path[^1].nibble = inx.int8
|
|
return xPath.completeMost(link, getFn)
|
|
|
|
# Restore `xPath` and backtrack
|
|
xPath.path.setLen(xPathLen)
|
|
xPath.tail = xPathTail
|
|
|
|
# Pop `Branch` node on top and append nibble to `tail`
|
|
xPath.tail = @[top.nibble.byte].initNibbleRange.slice(1) & xPath.tail
|
|
xPath.path.setLen(xPath.path.len - 1)
|
|
|
|
# Pathological case: n00000.. for 0 < n
|
|
var step = path.path[0]
|
|
for inx in (step.nibble - 1).countDown(0):
|
|
let link = step.node.bLink[inx]
|
|
if 0 < link.len:
|
|
step.nibble = inx.int8
|
|
xPath.path = @[step]
|
|
return xPath.completeMost(link, getFn)
|
|
|
|
err(NearbyFailed) # error
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Public functions, convenience wrappers
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc hexaryNearbyRight*(
|
|
baseTag: NodeTag; ## Some node
|
|
rootKey: NodeKey; ## State root
|
|
db: HexaryTreeDbRef; ## Database
|
|
): Result[NodeTag,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError]} =
|
|
## Variant of `hexaryNearbyRight()` working with `NodeTag` arguments rather
|
|
## than `RPath()` ones.
|
|
noRlpErrorOops("hexaryNearbyRight"):
|
|
return baseTag.hexaryNearbyRightImpl(rootKey, db)
|
|
|
|
proc hexaryNearbyRight*(
|
|
baseTag: NodeTag; ## Some node
|
|
rootKey: NodeKey; ## State root
|
|
getFn: HexaryGetFn; ## Database abstraction
|
|
): Result[NodeTag,HexaryError]
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
## Variant of `hexaryNearbyRight()` for persistant database
|
|
noKeyErrorOops("hexaryNearbyRight"):
|
|
return baseTag.hexaryNearbyRightImpl(rootKey, getFn)
|
|
|
|
|
|
proc hexaryNearbyLeft*(
|
|
baseTag: NodeTag; ## Some node
|
|
rootKey: NodeKey; ## State root
|
|
db: HexaryTreeDbRef; ## Database
|
|
): Result[NodeTag,HexaryError]
|
|
{.gcsafe, raises: [Defect,KeyError]} =
|
|
## Similar to `hexaryNearbyRight()` for `NodeKey` arguments.
|
|
noRlpErrorOops("hexaryNearbyLeft"):
|
|
return baseTag.hexaryNearbyLeftImpl(rootKey, db)
|
|
|
|
proc hexaryNearbyLeft*(
|
|
baseTag: NodeTag; ## Some node
|
|
rootKey: NodeKey; ## State root
|
|
getFn: HexaryGetFn; ## Database abstraction
|
|
): Result[NodeTag,HexaryError]
|
|
{.gcsafe, raises: [Defect,RlpError]} =
|
|
## Variant of `hexaryNearbyLeft()` for persistant database
|
|
noKeyErrorOops("hexaryNearbyLeft"):
|
|
return baseTag.hexaryNearbyLeftImpl(rootKey, getFn)
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# End
|
|
# ------------------------------------------------------------------------------
|