nimbus-eth1/nimbus/db/aristo/aristo_vid.nim

# nimbus-eth1
# Copyright (c) 2023-2024 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
  std/typetraits,
  ./aristo_desc

# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------

proc vidFetch*(db: AristoDbRef; pristine = false): VertexID =
  ## Fetch next vertex ID.
  ##
  if db.top.delta.vTop  == 0:
    db.top.delta.vTop = VertexID(LEAST_FREE_VID)
  else:
    db.top.delta.vTop.inc
  db.top.delta.vTop

proc vidDispose*(db: AristoDbRef; vid: VertexID) =
  ## Only top vertexIDs are disposed
  if vid == db.top.delta.vTop and
     LEAST_FREE_VID < db.top.delta.vTop.distinctBase:
    db.top.delta.vTop.dec

# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------