nimbus-eth1/nimbus/db/kvt/kvt_desc/desc_backend.nim

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# 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.
## Kvt DB -- backend data types
## ============================
##
{.push raises: [].}
import
eth/common,
results,
./desc_error
type
GetKvpFn* =
Aristo db api extensions for use as core db backend (#1754) * Update docu * Update Aristo/Kvt constructor prototype why: Previous version used an `enum` value to indicate what backend is to be used. This was replaced by using the backend object type. * Rewrite `hikeUp()` return code into `Result[Hike,(Hike,AristoError)]` why: Better code maintenance. Previously, the `Hike` object was returned. It had an internal error field so partial success was also available on a failure. This error field has been removed. * Use `openArray[byte]` rather than `Blob` in functions prototypes * Provide synchronised multi instance transactions why: The `CoreDB` object was geared towards the legacy DB which used a single transaction for the key-value backend DB. Different state roots are provided by the backend database, so all instances work directly on the same backend. Aristo db instances have different in-memory mappings (aka different state roots) and the transactions are on top of there mappings. So each instance might run different transactions. Multi instance transactions are a compromise to converge towards the legacy behaviour. The synchronised transactions span over all instances available at the time when base transaction was opened. Instances created later are unaffected. * Provide key-value pair database iterator why: Needed in `CoreDB` for `replicate()` emulation also: Some update of internal code * Extend API (i.e. prototype variants) why: Needed for `CoreDB` geared towards the legacy backend which has a more basic API than Aristo.
2023-09-15 15:23:53 +00:00
proc(key: openArray[byte]): Result[Blob,KvtError] {.gcsafe, raises: [].}
## Generic backend database retrieval function
LenKvpFn* =
proc(key: openArray[byte]): Result[int,KvtError] {.gcsafe, raises: [].}
## Generic backend database retrieval function
# -------------
PutHdlRef* = ref object of RootRef
## Persistent database transaction frame handle. This handle is used to
## wrap any of `PutVtxFn`, `PutKeyFn`, and `PutIdgFn` into and atomic
## transaction frame. These transaction frames must not be interleaved
## by any library function using the backend.
PutBegFn* =
proc(): Result[PutHdlRef,KvtError] {.gcsafe, raises: [].}
## Generic transaction initialisation function
PutKvpFn* =
proc(hdl: PutHdlRef; k, v: openArray[byte]) {.gcsafe, raises: [].}
## Generic backend database bulk storage function.
PutEndFn* =
proc(hdl: PutHdlRef): Result[void,KvtError] {.gcsafe, raises: [].}
## Generic transaction termination function
# -------------
CloseFn* =
proc(eradicate: bool) {.gcsafe, raises: [].}
## Generic destructor for the `Kvt DB` backend. The argument `eradicate`
## indicates that a full database deletion is requested. If passed
## `false` the outcome might differ depending on the type of backend
## (e.g. in-memory backends would eradicate on close.)
CanModFn* =
proc(): Result[void,KvtError] {.gcsafe, raises: [].}
## This function returns OK if there is nothing to prevent the main
## `KVT` descriptors being modified (e.g. by `reCentre()`) or by
## adding/removing a new peer (e.g. by `fork()` or `forget()`.)
SetWrReqFn* =
proc(db: RootRef): Result[void,KvtError] {.gcsafe, raises: [].}
## This function stores a request function for the piggiback mode
## writing to the `Aristo` set of column families.
##
## If used at all, this function would run thee function closure
## `rocks_db.setWrReqTriggeredFn()()` with a `KvtDbRef` type argument
## for `db`. This allows to run the `Kvt` without linking to the
## rocksdb interface unless it is really needed.
# -------------
BackendRef* = ref BackendObj
BackendObj* = object of RootObj
## Backend interface.
getKvpFn*: GetKvpFn ## Read key-value pair
lenKvpFn*: LenKvpFn ## Read key-value pair length
putBegFn*: PutBegFn ## Start bulk store session
putKvpFn*: PutKvpFn ## Bulk store key-value pairs
putEndFn*: PutEndFn ## Commit bulk store session
closeFn*: CloseFn ## Generic destructor
canModFn*: CanModFn ## Lock-alike
setWrReqFn*: SetWrReqFn ## Register main descr for write request
proc init*(trg: var BackendObj; src: BackendObj) =
trg.getKvpFn = src.getKvpFn
trg.lenKvpFn = src.lenKvpFn
trg.putBegFn = src.putBegFn
trg.putKvpFn = src.putKvpFn
trg.putEndFn = src.putEndFn
trg.closeFn = src.closeFn
trg.canModFn = src.canModFn
trg.setWrReqFn = src.setWrReqFn
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------