2025-02-11 10:54:58 +01:00

121 lines
3.0 KiB
Nim

import pkg/chronos
import pkg/chronicles
import pkg/metrics
import pkg/datastore
import pkg/datastore/typedds
import pkg/stew/byteutils
import pkg/stew/endians2
import pkg/questionable
import pkg/questionable/results
import pkg/stint
import std/sets
import std/sequtils
import std/os
import ./types
logScope:
topics = "list"
type
OnUpdateMetric = proc(value: int64): void {.gcsafe, raises: [].}
List* = ref object
name: string
store: TypedDatastore
items: HashSet[Nid]
onMetric: OnUpdateMetric
emptySignal: ?Future[void]
proc encode(s: Nid): seq[byte] =
s.toBytes()
proc decode(T: type Nid, bytes: seq[byte]): ?!T =
if bytes.len < 1:
return success(Nid.fromStr("0"))
return Nid.fromBytes(bytes)
proc saveItem(this: List, item: Nid): Future[?!void] {.async.} =
without itemKey =? Key.init(this.name / $item), err:
return failure(err)
?await this.store.put(itemKey, item)
return success()
proc load*(this: List): Future[?!void] {.async.} =
let id = Nid.fromStr("0")
let bytes = newSeq[byte]()
let ne = Nid.fromBytes(bytes)
without queryKey =? Key.init(this.name), err:
return failure(err)
without iter =? (await query[Nid](this.store, Query.init(queryKey))), err:
return failure(err)
while not iter.finished:
without item =? (await iter.next()), err:
return failure(err)
without value =? item.value, err:
return failure(err)
if value > 0:
this.items.incl(value)
this.onMetric(this.items.len.int64)
info "Loaded list", name = this.name, items = this.items.len
return success()
proc new*(
_: type List, name: string, store: TypedDatastore, onMetric: OnUpdateMetric
): List =
List(name: name, store: store, onMetric: onMetric)
proc contains*(this: List, nid: Nid): bool =
this.items.anyIt(it == nid)
proc add*(this: List, nid: Nid): Future[?!void] {.async.} =
if this.contains(nid):
return success()
this.items.incl(nid)
this.onMetric(this.items.len.int64)
if err =? (await this.saveItem(nid)).errorOption:
return failure(err)
if s =? this.emptySignal:
trace "List no longer empty.", name = this.name
s.complete()
this.emptySignal = Future[void].none
return success()
proc remove*(this: List, nid: Nid): Future[?!void] {.async.} =
if this.items.len < 1:
return failure(this.name & "List is empty.")
this.items.excl(nid)
without itemKey =? Key.init(this.name / $nid), err:
return failure(err)
?await this.store.delete(itemKey)
this.onMetric(this.items.len.int64)
return success()
proc pop*(this: List): Future[?!Nid] {.async.} =
if this.items.len < 1:
trace "List is empty. Waiting for new items...", name = this.name
let signal = newFuture[void]("list.emptySignal")
this.emptySignal = some(signal)
await signal.wait(1.hours)
if this.items.len < 1:
return failure(this.name & "List is empty.")
let item = this.items.pop()
if err =? (await this.remove(item)).errorOption:
return failure(err)
return success(item)
proc len*(this: List): int =
this.items.len