nimbus-eth1/nimbus/db/kvt/kvt_delta/delta_reverse.nim

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1.6 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,
results,
".."/[kvt_desc, kvt_utils]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc deltaReverse*(
db: KvtDbRef; # Database
delta: LayerDeltaRef; # Filter to revert
): LayerDeltaRef =
## Assemble a reverse filter for the `delta` argument, i.e. changes to the
## backend that reverse the effect of applying this to the balancer filter.
## The resulting filter is calculated against the current *unfiltered*
## backend (excluding optionally installed balancer filters.)
##
## If `delta` is `nil`, the result will be `nil` as well.
if not delta.isNil:
result = LayerDeltaRef()
# Calculate reverse changes for the `sTab[]` structural table
for key in delta.sTab.keys:
let rc = db.getUbe key
if rc.isOk:
result.sTab[key] = rc.value
else:
doAssert rc.error == GetNotFound
result.sTab[key] = EmptyBlob
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------