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

48 lines
1.7 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,
results,
".."/[kvt_desc, kvt_utils]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc merge*(
db: KvtDbRef; # Database
upper: LayerDeltaRef; # Filter to apply onto `lower`
lower: var LayerDeltaRef; # Target filter, will be modified
) =
## Merge the argument filter `upper` onto the argument filter `lower`
## relative to the *unfiltered* backend database on `db.backened`. The `lower`
## filter argument will have been modified.
##
## In case that the argument `lower` is `nil`, it will be replaced by `upper`.
##
if lower.isNil:
lower = upper
elif not upper.isNil:
for (key,val) in upper.sTab.pairs:
if val.isValid or not lower.sTab.hasKey key:
lower.sTab[key] = val
elif lower.sTab.getOrVoid(key).isValid:
let rc = db.getUbe key
if rc.isOk:
lower.sTab[key] = val # empty blob
else:
doAssert rc.error == GetNotFound
lower.sTab.del key # no need to keep that in merged filter
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------