80 lines
2.4 KiB
Nim
80 lines
2.4 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.
|
||
|
|
|
||
|
|
## Handle vertex IDs on the layered Aristo DB delta architecture
|
||
|
|
## =============================================================
|
||
|
|
|
||
|
|
{.push raises: [].}
|
||
|
|
|
||
|
|
import
|
||
|
|
./aristo_desc
|
||
|
|
|
||
|
|
# ------------------------------------------------------------------------------
|
||
|
|
# Public functions
|
||
|
|
# ------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
proc vidFetch*(db: AristoDbRef): VertexID =
|
||
|
|
## Create a new `VertexID`. Reusable *ID*s are kept in a list where the top
|
||
|
|
## entry *ID0* has the property that any other *ID* larger *ID0* is also not
|
||
|
|
## not used on the database.
|
||
|
|
|
||
|
|
# Down the rabbit hole of transaction layers
|
||
|
|
let xDb = if db.cascaded: db.base else: db
|
||
|
|
|
||
|
|
case xDb.vidGen.len:
|
||
|
|
of 0:
|
||
|
|
xDb.vidGen = @[2.VertexID]
|
||
|
|
result = 1.VertexID
|
||
|
|
of 1:
|
||
|
|
result = xDb.vidGen[^1]
|
||
|
|
xDb.vidGen = @[(result.uint64 + 1).VertexID]
|
||
|
|
else:
|
||
|
|
result = xDb.vidGen[^2]
|
||
|
|
xDb.vidGen[^2] = xDb.vidGen[^1]
|
||
|
|
xDb.vidGen.setLen(xDb.vidGen.len-1)
|
||
|
|
|
||
|
|
|
||
|
|
proc vidPeek*(db: AristoDbRef): VertexID =
|
||
|
|
## Like `new()` without consuming this *ID*. It will return the *ID* that
|
||
|
|
## would be returned by the `new()` function.
|
||
|
|
|
||
|
|
# Down the rabbit hole of transaction layers
|
||
|
|
let xDb = if db.cascaded: db.base else: db
|
||
|
|
|
||
|
|
case xDb.vidGen.len:
|
||
|
|
of 0:
|
||
|
|
1.VertexID
|
||
|
|
of 1:
|
||
|
|
xDb.vidGen[^1]
|
||
|
|
else:
|
||
|
|
xDb.vidGen[^2]
|
||
|
|
|
||
|
|
|
||
|
|
proc vidDispose*(db: AristoDbRef; vtxID: VertexID) =
|
||
|
|
## Recycle the argument `vtxID` which is useful after deleting entries from
|
||
|
|
## the vertex table to prevent the `VertexID` type key values small.
|
||
|
|
|
||
|
|
# Down the rabbit hole of transaction layers
|
||
|
|
let xDb = if db.cascaded: db.base else: db
|
||
|
|
|
||
|
|
if xDb.vidGen.len == 0:
|
||
|
|
xDb.vidGen = @[vtxID]
|
||
|
|
else:
|
||
|
|
let topID = xDb.vidGen[^1]
|
||
|
|
# No need to store smaller numbers: all numberts larger than `topID`
|
||
|
|
# are free numbers
|
||
|
|
if vtxID < topID:
|
||
|
|
xDb.vidGen[^1] = vtxID
|
||
|
|
xDb.vidGen.add topID
|
||
|
|
|
||
|
|
# ------------------------------------------------------------------------------
|
||
|
|
# End
|
||
|
|
# ------------------------------------------------------------------------------
|