118 lines
4.0 KiB
Nim
118 lines
4.0 KiB
Nim
# nimbus-eth1
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# Copyright (c) 2023-2024 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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import
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results,
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eth/common,
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../aristo_desc,
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"."/[delta_merge, delta_reverse]
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type
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UpdateState = enum
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Initial = 0
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Updated,
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Finished
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UpdateSiblingsRef* = ref object
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## Update transactional context
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state: UpdateState
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db: AristoDbRef ## Main database access
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balancers: seq[(AristoDbRef,LayerDeltaRef)] ## Rollback data
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rev: LayerDeltaRef ## Reverse filter set up
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# ------------------------------------------------------------------------------
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# Public contructor, commit, rollback
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# ------------------------------------------------------------------------------
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proc rollback*(ctx: UpdateSiblingsRef) =
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## Rollback any changes made by the `update()` function. Subsequent
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## `rollback()` or `commit()` calls will be without effect.
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if ctx.state == Updated:
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for (d,f) in ctx.balancers:
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d.balancer = f
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ctx.state = Finished
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proc commit*(ctx: UpdateSiblingsRef): Result[void,AristoError] =
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## Accept updates. Subsequent `rollback()` calls will be without effect.
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if ctx.state != Updated:
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ctx.rollback()
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return err(FilSiblingsCommitUnfinshed)
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ctx.db.balancer = LayerDeltaRef(nil)
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ctx.state = Finished
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ok()
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proc commit*(
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rc: Result[UpdateSiblingsRef,AristoError];
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): Result[void,AristoError] =
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## Variant of `commit()` for joining with `update()`
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(? rc).commit()
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proc init*(
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T: type UpdateSiblingsRef; # Context type
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db: AristoDbRef; # Main database
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): Result[T,AristoError] =
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## Set up environment for installing the reverse of the `db` argument current
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## read-only filter onto every associated descriptor referring to the same
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## database.
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if not db.isCentre:
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return err(FilBackendRoMode)
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if db.nForked == 0:
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return ok T(db: db) # No need to do anything
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func fromVae(err: (VertexID,AristoError)): AristoError =
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err[1]
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# Filter rollback context
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ok T(
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db: db,
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rev: ? db.revFilter(db.balancer).mapErr fromVae) # Reverse filter
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc update*(ctx: UpdateSiblingsRef): Result[UpdateSiblingsRef,AristoError] =
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## This function installs the reverse of the `init()` argument `db` current
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## read-only filter onto every associated descriptor referring to the same
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## database. If the function fails, a `rollback()` is called automatically.
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##
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## This function might do some real work so it was detached from `init()` so
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## it can be called late but before the physical database is updated.
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##
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if ctx.state == Initial:
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ctx.state = Updated
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if not ctx.rev.isNil:
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let db = ctx.db
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# Update distributed filters. Note that the physical backend database
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# must not have been updated, yet. So the new root key for the backend
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# will be `db.balancer.kMap[$1]`.
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let trg = db.balancer.kMap.getOrVoid((VertexID(1), VertexID(1)))
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for w in db.forked:
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let rc = db.deltaMerge(w.balancer, ctx.rev, trg)
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if rc.isErr:
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ctx.rollback()
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return err(rc.error[1])
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ctx.balancers.add (w, w.balancer)
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w.balancer = rc.value
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ok(ctx)
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proc update*(
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rc: Result[UpdateSiblingsRef,AristoError]
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): Result[UpdateSiblingsRef,AristoError] =
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## Variant of `update()` for joining with `init()`
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(? rc).update()
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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