nimbus-eth1/nimbus/db/aristo/aristo_part/part_ctx.nim

177 lines
5.0 KiB
Nim

# nimbus-eth1
# Copyright (c) 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.
{.push raises: [].}
import
std/sets,
eth/common,
results,
".."/[aristo_desc, aristo_get, aristo_hike, aristo_layers, aristo_utils],
#./part_debug,
./part_desc
# ------------------------------------------------------------------------------
# Private functions
# ------------------------------------------------------------------------------
proc newCtx(ps: PartStateRef; hike: Hike): Result[PartStateCtx,AristoError] =
## ..
doAssert 0 <= hike.legs[^1].nibble
let
wp = hike.legs[^1].wp
nibble = hike.legs[^1].nibble
fromVid = wp.vtx.bVid[nibble]
if not ps.isPerimeter(fromVid) or ps.isExtension(fromVid):
return err(PartCtxNotAvailable)
let
vtx2 = wp.vtx.dup
psc = PartStateCtx(
ps: ps,
location: (hike.root,wp.vid),
nibble: nibble,
fromVid: fromVid)
# Update database so that is space for adding a new sub-tree here
vtx2.bVid[nibble] = VertexID(0)
ps.db.layersPutVtx(psc.location,vtx2)
ok psc
proc removedCompletedNode(
ps: PartStateRef;
rvid: RootedVertexID;
key: HashKey;
): bool =
let vtx = ps.db.getVtx rvid
if vtx.isNil:
return false
var subVids: seq[VertexID]
for vid in vtx.subVids():
# Only accept perimeter nodes with all links on the database (i.e. links
# must nor refere t a core node.)
if not ps.db.getVtx((rvid.root, vid)).isValid or ps.isCore(vid):
return false # not complete
subVids.add vid
# No need to keep that core vertex any longer
ps.delCore(rvid.root, key)
for vid in subVids:
ps.del vid
true
proc removeCompletedNodes(ps: PartStateRef; rvid: RootedVertexID) =
let key = ps[rvid.vid]
if ps.removedCompletedNode(rvid, key):
# Rather stupid loop to clear additional nodes. Note that the set
# of core nodes is assumed to be small, i.e. not more than a hand full.
while true:
ps.core.withValue(rvid.root, coreKeys):
block removeItem:
for cKey in coreKeys[]:
let rv = ps[cKey]
if ps.removedCompletedNode(rv, cKey):
break removeItem # continue `while`
return # done
do: return # done
# -------------------
proc ctxAcceptChange(psc: PartStateCtx): Result[bool,AristoError] =
## Apply `psc` context if there was a change on the targeted vertex,
## otherwise restore. Returns `true` exactly if there was a change on
## the database which could be applied.
##
let
ps = psc.ps
db = ps.db
(vtx,_) = ? db.getVtxRc psc.location
toVid = vtx.bVid[psc.nibble]
if not toVid.isValid:
# Nothing changed, so restore
let vtx2 = vtx.dup
vtx2.bVid[psc.nibble] = psc.fromVid
db.layersPutVtx(psc.location, vtx2)
ok(false)
elif toVid != psc.fromVid:
# Replace `fromVid` by `toVid` in state descriptor `ps`
let key = ps.move(psc.fromVid, toVid)
doAssert key.isValid
ps.changed.incl key
# Remove parent vertex it it has become complete.
ps.removeCompletedNodes(psc.location)
ok(true)
else:
ok(false)
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc ctxMergeBegin*(
ps: PartStateRef;
root: VertexID;
path: openArray[byte];
): Result[PartStateCtx,AristoError] =
## This function clears the way for mering some payload at the argument
## path `(root,path)`.
let hike = block:
let rc = NibblesBuf.fromBytes(path).hikeUp(root,ps.db)
if rc.isOk:
return ok PartStateCtx(nil) # Nothing to do
if rc.error[1] != HikeDanglingEdge:
return err( rc.error[1]) # Cannot help here
rc.to(Hike)
ps.newCtx hike
proc ctxMergeBegin*(
ps: PartStateRef;
accPath: Hash256;
): Result[PartStateCtx,AristoError] =
## Variant of `partMergeBegin()` for different path representation
ps.ctxMergeBegin(VertexID(1), accPath.data)
proc ctxMergeCommit*(psc: PartStateCtx): Result[bool,AristoError] =
##
if psc.isNil:
return ok(false) # Nothing to do
if psc.ps.isNil:
return err(PartCtxStaleDescriptor)
let yn = ? psc.ctxAcceptChange()
psc[].reset
ok(yn)
proc ctxMergeRollback*(psc: PartStateCtx): Result[void,AristoError] =
## ..
if psc.isNil:
return ok() # Nothing to do
if psc.ps.isNil:
return err(PartCtxStaleDescriptor)
let yn = ? psc.ctxAcceptChange()
psc[].reset
if yn: err(PartVtxSlotWasModified) else: ok()
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------