118 lines
4.2 KiB
Nim
118 lines
4.2 KiB
Nim
# nimbus-eth1
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# Copyright (c) 2021 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed
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# except according to those terms.
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## Aristo DB -- a Patricia Trie with labeled edges
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## ===============================================
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##
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## These data structures allows to overlay the *Patricia Trie* with *Merkel
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## Trie* hashes. See the `README.md` in the `aristo` folder for documentation.
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##
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## Some semantic explanations;
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##
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## * HashKey, NodeRef etc. refer to the standard/legacy `Merkle Patricia Tree`
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## * VertexID, VertexRef, etc. refer to the `Aristo Trie`
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##
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{.push raises: [].}
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import
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std/[sets, tables],
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eth/common,
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./aristo_constants,
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./aristo_desc/[
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aristo_error, aristo_types_backend,
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aristo_types_identifiers, aristo_types_structural]
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export
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# Not auto-exporting backend
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aristo_constants, aristo_error, aristo_types_identifiers,
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aristo_types_structural
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type
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AristoChangeLogRef* = ref object
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## Change log: database state before backend saving.
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root*: HashKey ## Previous hash key for `VertexID(1)`
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leafs*: Table[LeafTie,PayloadRef] ## Changed leafs after merge into backend
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AristoLayerRef* = ref object
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## Hexary trie database layer structures. Any layer holds the full
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## change relative to the backend.
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sTab*: Table[VertexID,VertexRef] ## Structural vertex table
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lTab*: Table[LeafTie,VertexID] ## Direct access, path to leaf vertex
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kMap*: Table[VertexID,HashLabel] ## Merkle hash key mapping
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pAmk*: Table[HashLabel,VertexID] ## Reverse `kMap` entries, hash key lookup
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pPrf*: HashSet[VertexID] ## Locked vertices (proof nodes)
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vGen*: seq[VertexID] ## Unique vertex ID generator
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AristoDbRef* = ref AristoDbObj
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AristoDbObj* = object
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## Set of database layers, supporting transaction frames
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top*: AristoLayerRef ## Database working layer, mutable
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stack*: seq[AristoLayerRef] ## Stashed immutable parent layers
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backend*: AristoBackendRef ## Backend database (may well be `nil`)
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history*: seq[AristoChangeLogRef] ## Backend saving history
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# Debugging data below, might go away in future
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xMap*: Table[HashLabel,VertexID] ## For pretty printing, extends `pAmk`
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# ------------------------------------------------------------------------------
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# Public helpers
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# ------------------------------------------------------------------------------
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func getOrVoid*[W](tab: Table[W,VertexRef]; w: W): VertexRef =
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tab.getOrDefault(w, VertexRef(nil))
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func getOrVoid*[W](tab: Table[W,HashLabel]; w: W): HashLabel =
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tab.getOrDefault(w, VOID_HASH_LABEL)
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func getOrVoid*[W](tab: Table[W,VertexID]; w: W): VertexID =
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tab.getOrDefault(w, VertexID(0))
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# --------
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func isValid*(vtx: VertexRef): bool =
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vtx != VertexRef(nil)
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func isValid*(nd: NodeRef): bool =
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nd != NodeRef(nil)
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func isValid*(pld: PayloadRef): bool =
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pld != PayloadRef(nil)
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func isValid*(key: HashKey): bool =
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key != VOID_HASH_KEY
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func isValid*(lbl: HashLabel): bool =
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lbl != VOID_HASH_LABEL
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func isValid*(vid: VertexID): bool =
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vid != VertexID(0)
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# ------------------------------------------------------------------------------
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# Public functions, miscellaneous
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# ------------------------------------------------------------------------------
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# Note that the below `init()` function cannot go into
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# `aristo_types_identifiers` as this would result in a circular import.
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func init*(key: var HashKey; data: openArray[byte]): bool =
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## Import argument `data` into `key` which must have length either `32`, or
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## `0`. The latter case is equivalent to an all zero byte array of size `32`.
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if data.len == 32:
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(addr key.ByteArray32[0]).copyMem(unsafeAddr data[0], data.len)
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return true
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if data.len == 0:
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key = VOID_HASH_KEY
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return true
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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