nimbus-eth1/nimbus/db/aristo/aristo_get.nim

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3.3 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.
## Read vertex record on the layered Aristo DB delta architecture
## ==============================================================
{.push raises: [].}
import
std/tables,
stew/results,
"."/aristo_desc
type
VidVtxPair* = object
vid*: VertexID ## Table lookup vertex ID (if any)
vtx*: VertexRef ## Reference to vertex
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc getVtxBackend*(
db: AristoDbRef;
vid: VertexID;
): Result[VertexRef,AristoError] =
## Get the vertex from the `backened` layer if available.
let be = db.backend
if not be.isNil:
return be.getVtxFn vid
err(GetVtxNotFound)
proc getKeyBackend*(
db: AristoDbRef;
vid: VertexID;
): Result[HashKey,AristoError] =
## Get the merkle hash/key from the backend
let be = db.backend
if not be.isNil:
return be.getKeyFn vid
err(GetKeyNotFound)
# ------------------
proc getLeaf*(
db: AristoDbRef;
lty: LeafTie;
): Result[VidVtxPair,AristoError] =
## Get the vertex from the top layer by the `Patricia Trie` path. This
## function does not search on the `backend` layer.
let vid = db.top.lTab.getOrVoid lty
if not vid.isValid:
return err(GetLeafNotFound)
let vtx = db.top.sTab.getOrVoid vid
if not vtx.isValid:
return err(GetVtxNotFound)
ok VidVtxPair(vid: vid, vtx: vtx)
proc getLeafVtx*(db: AristoDbRef; lty: LeafTie): VertexRef =
## Variant of `getLeaf()` returning `nil` on error (while ignoring the
## detailed error type information.)
##
let rc = db.getLeaf lty
if rc.isOk:
return rc.value.vtx
# ------------------
proc getVtx*(db: AristoDbRef; vid: VertexID): VertexRef =
## Cascaded attempt to fetch a vertex from the top layer or the backend.
## The function returns `nil` on error or failure.
##
if db.top.sTab.hasKey vid:
# If the vertex is to be deleted on the backend, a `VertexRef(nil)` entry
# is kept in the local table in which case it is OK to return this value.
return db.top.sTab.getOrVoid vid
let rc = db.getVtxBackend vid
if rc.isOk:
return rc.value
VertexRef(nil)
proc getKey*(db: AristoDbRef; vid: VertexID): HashKey =
## Cascaded attempt to fetch a Merkle hash from the top layer or the backend.
## The function returns `VOID_HASH_KEY` on error or failure.
##
if db.top.kMap.hasKey vid:
# If the key is to be deleted on the backend, a `VOID_HASH_LABEL` entry
# is kept on the local table in which case it is OK to return this value.
return db.top.kMap.getOrVoid(vid).key
let rc = db.getKeyBackend vid
if rc.isOk:
return rc.value
VOID_HASH_KEY
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------