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

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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, ".."/[kvt_desc, kvt_utils]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc revFilter*(
db: KvtDbRef, # Database
filter: LayerRef, # Filter to revert
): Result[LayerRef, (Blob, KvtError)] =
## Assemble reverse filter for the `filter` argument, i.e. changes to the
## backend that reverse the effect of applying the this read-only filter.
##
## This read-only filter is calculated against the current unfiltered
## backend (excluding optionally installed read-only filter.)
##
let rev = LayerRef()
# Calculate reverse changes for the `sTab[]` structural table
for key in filter.sTab.keys:
let rc = db.getUbe key
if rc.isOk:
rev.sTab[key] = rc.value
elif rc.error == GetNotFound:
rev.sTab[key] = EmptyBlob
else:
return err((key, rc.error))
ok(rev)
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------