nimbus-eth1/nimbus/db/aristo/aristo_fetch.nim
Jordan Hrycaj 71c91e2280
Aristo db refactor tx paradim (#1674)
* Better error handling

why:
  Bail out on some error as early as possible before any changes.

* Implement `fetch()` as opposite of `merge()`

rationale:
  In the `Aristo` realm, the action named `fetch()` and `merge()` indicate
  leaf value related actions on the MPT, while actions `get()` and `put()`
   handle vertex or hash key related operations that constitute the MPT.

* Re-factor `merge()` prototypes

why:
  The most used variant of `merge()` should have the simplest prototype.

* Persistent DB constructor needs to import `aristo/aristo_init/persistent`

why:
  Most applications use memory DB anyway. This avoids linking `-lrocksdb`
  or any other back end libraries by default.

* Re-factor transaction module

why:
  Got the paradigm wrong. The transaction descriptor did replace the
  database one but should be handled separately.
2023-08-07 18:45:23 +01:00

43 lines
1.4 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.
## 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
# ------------------------------------------------------------------------------