133 lines
4.4 KiB
Nim
133 lines
4.4 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 -- Patricia Trie layer management
|
|
## ===========================================
|
|
##
|
|
|
|
import
|
|
std/[sequtils, tables],
|
|
stew/results,
|
|
"."/[aristo_desc, aristo_get, aristo_vid]
|
|
|
|
type
|
|
DeltaHistoryRef* = ref object
|
|
## Change history for backend saving
|
|
leafs*: Table[LeafTie,PayloadRef] ## Changed leafs after merge into backend
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Private functions
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc cpy(layer: AristoLayerRef): AristoLayerRef =
|
|
new result
|
|
result[] = layer[]
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Public functions
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc push*(db: var AristoDb) =
|
|
## Save a copy of the current delta state on the stack of non-persistent
|
|
## state layers.
|
|
db.stack.add db.top.cpy
|
|
|
|
|
|
proc pop*(db: var AristoDb; merge = true): AristoError =
|
|
## Remove the current state later and merge it into the next layer if the
|
|
## argument `merge` is `true`, and discard it otherwise. The next layer then
|
|
## becomes the current state.
|
|
##
|
|
## Note that merging is sort of a virtual action because the top layer has
|
|
## always the full latest non-persistent delta state. This implies that in
|
|
## the case of *merging* just the first parent layer will be discarded.
|
|
##
|
|
if 0 < db.stack.len:
|
|
if not merge:
|
|
# Roll back to parent layer state
|
|
db.top = db.stack[^1]
|
|
db.stack.setLen(db.stack.len-1)
|
|
|
|
elif merge:
|
|
# Accept as-is (there is no parent layer)
|
|
discard
|
|
|
|
elif db.backend.isNil:
|
|
db.top = AristoLayerRef()
|
|
|
|
else:
|
|
# Initialise new top layer from the backend
|
|
let rc = db.backend.getIdgFn()
|
|
if rc.isErr:
|
|
return rc.error
|
|
db.top = AristoLayerRef(vGen: rc.value)
|
|
|
|
AristoError(0)
|
|
|
|
|
|
proc save*(
|
|
db: var AristoDb; # Database to be updated
|
|
clear = true; # Clear current top level cache
|
|
): Result[DeltaHistoryRef,(VertexID,AristoError)] =
|
|
## Save top layer into persistent database. There is no check whether the
|
|
## current layer is fully consistent as a Merkle Patricia Tree. It is
|
|
## advised to run `hashify()` on the top layer before calling `save()`.
|
|
##
|
|
## After successful storage, all parent layers are cleared. The top layer
|
|
## is also cleared if the `clear` flag is set `true`.
|
|
##
|
|
## Upon successful return, the previous state of the backend data is returned
|
|
## relative to the changes made.
|
|
##
|
|
let be = db.backend
|
|
if be.isNil:
|
|
return err((VertexID(0),SaveBackendMissing))
|
|
|
|
let hst = DeltaHistoryRef() # Change history
|
|
|
|
# Record changed `Leaf` nodes into the history table
|
|
for (lky,vid) in db.top.lTab.pairs:
|
|
if vid.isValid:
|
|
# Get previous payload for this vertex
|
|
let rc = db.getVtxBackend vid
|
|
if rc.isErr:
|
|
if rc.error != GetVtxNotFound:
|
|
return err((vid,rc.error)) # Stop
|
|
hst.leafs[lky] = PayloadRef(nil) # So this is a new leaf vertex
|
|
elif rc.value.vType == Leaf:
|
|
hst.leafs[lky] = rc.value.lData # Record previous payload
|
|
else:
|
|
return err((vid,SaveLeafVidRepurposed)) # Was re-puropsed
|
|
else:
|
|
hst.leafs[lky] = PayloadRef(nil) # New leaf vertex
|
|
|
|
# Compact recycled nodes
|
|
db.vidReorg()
|
|
|
|
# Save structural and other table entries
|
|
let txFrame = be.putBegFn()
|
|
be.putVtxFn(txFrame, db.top.sTab.pairs.toSeq)
|
|
be.putKeyFn(txFrame, db.top.kMap.pairs.toSeq.mapIt((it[0],it[1].key)))
|
|
be.putIdgFn(txFrame, db.top.vGen)
|
|
let w = be.putEndFn txFrame
|
|
if w != AristoError(0):
|
|
return err((VertexID(0),w))
|
|
|
|
# Delete stack and clear top
|
|
db.stack.setLen(0)
|
|
if clear:
|
|
db.top = AristoLayerRef(vGen: db.top.vGen)
|
|
|
|
ok hst
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# End
|
|
# ------------------------------------------------------------------------------
|