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

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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.
## Aristo DB -- Obects Retrival Via Traversal Path
## ===============================================
##
{.push raises: [].}
import
eth/common,
results,
"."/[aristo_desc, aristo_hike]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc fetchPayload*(
db: AristoDbRef;
key: LeafTie;
): Result[PayloadRef,(VertexID,AristoError)] =
## Cascaded attempt to traverse the `Aristo Trie` and fetch the value of a
## leaf vertex. This function is complementary to `merge()`.
##
let hike = key.hikeUp db
if hike.error != AristoError(0):
let vid =
if hike.legs.len == 0: VertexID(0)
else: hike.legs[^1].wp.vid
return err((vid,hike.error))
ok hike.legs[^1].wp.vtx.lData
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------