nimbus-eth1/nimbus/db/aristo/aristo_init/memory_only.nim

100 lines
3.2 KiB
Nim

# nimbus-eth1
# Copyright (c) 2021 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.
## Non persistent constructors for Aristo DB
## =========================================
##
{.push raises: [].}
import
../aristo_desc,
../aristo_desc/desc_backend,
"."/[init_common, memory_db]
type
VoidBackendRef* = ref object of TypedBackendRef
## Dummy descriptor type, used as `nil` reference
MemOnlyBackend* = VoidBackendRef|MemBackendRef
export
BackendType,
MemBackendRef,
QidLayoutRef
let
DefaultQidLayoutRef* = DEFAULT_QID_QUEUES.to(QidLayoutRef)
# ------------------------------------------------------------------------------
# Public helpers
# ------------------------------------------------------------------------------
proc kind*(
be: BackendRef;
): BackendType =
## Retrieves the backend type symbol for a `be` backend database argument
## where `BackendVoid` is returned for the`nil` backend.
if be.isNil:
BackendVoid
else:
be.TypedBackendRef.beKind
# ------------------------------------------------------------------------------
# Public database constuctors, destructor
# ------------------------------------------------------------------------------
proc init*(
T: type AristoDbRef; # Target type
B: type MemOnlyBackend; # Backend type
qidLayout = DefaultQidLayoutRef; # Optional fifo schedule
): T =
## Memory backend constructor.
##
## If the `qidLayout` argument is set `QidLayoutRef(nil)`, the a backend
## database will not provide filter history management. Providing a different
## scheduler layout shoud be used with care as table access with different
## layouts might render the filter history data unmanageable.
##
when B is VoidBackendRef:
AristoDbRef(top: LayerRef())
elif B is MemBackendRef:
AristoDbRef(top: LayerRef(), backend: memoryBackend(qidLayout))
proc init*(
T: type AristoDbRef; # Target type
): T =
## Shortcut for `AristoDbRef.init(VoidBackendRef)`
AristoDbRef.init VoidBackendRef
proc finish*(db: AristoDbRef; flush = false) =
## Backend destructor. The argument `flush` indicates that a full database
## deletion is requested. If set `false` the outcome might differ depending
## on the type of backend (e.g. the `BackendMemory` backend will always
## flush on close.)
##
## In case of distributed descriptors accessing the same backend, all
## distributed descriptors will be destroyed.
##
## This distructor may be used on already *destructed* descriptors.
##
if not db.isNil:
if not db.backend.isNil:
db.backend.closeFn flush
let lebo = db.getCentre
discard lebo.forgetOthers()
lebo[] = AristoDbObj(top: LayerRef())
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------