nimbus-eth1/nimbus/db/aristo/aristo_delta/delta_merge.nim

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3.7 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.
import
std/tables,
eth/common,
results,
".."/[aristo_desc, aristo_get]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc deltaMerge*(
db: AristoDbRef;
upper: LayerDeltaRef; # Src filter, `nil` is ok
lower: LayerDeltaRef; # Trg filter, `nil` is ok
beStateRoot: HashKey; # Merkle hash key
): Result[LayerDeltaRef,(VertexID,AristoError)] =
## Merge argument `upper` into the `lower` filter instance.
##
## Note that the namimg `upper` and `lower` indicate that the filters are
## stacked and the database access is `upper -> lower -> backend` whereas
## the `src/trg` matching logic goes the other way round.
##
## The resuting filter has no `FilterID` set.
##
## Comparing before and after merge
## ::
## arguments | merged result
## --------------------------------+------------------------------------
## (src2==trg1) --> upper --> trg2 |
## | (src1==trg0) --> newFilter --> trg2
## (src1==trg0) --> lower --> trg1 |
## |
## beStateRoot --> trg0 |
##
# Degenerate case: `upper` is void
if lower.isNil:
if upper.isNil:
# Even more degenerate case when both filters are void
return ok LayerDeltaRef(nil)
if upper.src != beStateRoot:
return err((VertexID(1),FilStateRootMismatch))
return ok(upper)
# Degenerate case: `upper` is non-trivial and `lower` is void
if upper.isNil:
if lower.src != beStateRoot:
return err((VertexID(0), FilStateRootMismatch))
return ok(lower)
# Verify stackability
let lowerTrg = lower.kMap.getOrVoid VertexID(1)
if upper.src != lowerTrg:
return err((VertexID(0), FilTrgSrcMismatch))
if lower.src != beStateRoot:
return err((VertexID(0), FilStateRootMismatch))
# There is no need to deep copy table vertices as they will not be modified.
let newFilter = LayerDeltaRef(
src: lower.src,
sTab: lower.sTab,
kMap: lower.kMap,
vTop: upper.vTop)
for (vid,vtx) in upper.sTab.pairs:
if vtx.isValid or not newFilter.sTab.hasKey vid:
newFilter.sTab[vid] = vtx
elif newFilter.sTab.getOrVoid(vid).isValid:
let rc = db.getVtxUbe vid
if rc.isOk:
newFilter.sTab[vid] = vtx # VertexRef(nil)
elif rc.error == GetVtxNotFound:
newFilter.sTab.del vid
else:
return err((vid,rc.error))
for (vid,key) in upper.kMap.pairs:
if key.isValid or not newFilter.kMap.hasKey vid:
newFilter.kMap[vid] = key
elif newFilter.kMap.getOrVoid(vid).isValid:
let rc = db.getKeyUbe vid
if rc.isOk:
newFilter.kMap[vid] = key
elif rc.error == GetKeyNotFound:
newFilter.kMap.del vid
else:
return err((vid,rc.error))
# Check consistency
if (newFilter.src == newFilter.kMap.getOrVoid(VertexID 1)) !=
(newFilter.sTab.len == 0 and newFilter.kMap.len == 0):
return err((VertexID(0),FilSrcTrgInconsistent))
ok newFilter
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------