nim-codex/codex/utils/trackedfutures.nim

53 lines
1.3 KiB
Nim

import std/sugar
import std/tables
import pkg/chronos
import ../logutils
import ../utils/then
type
TrackedFutures* = ref object
futures: Table[uint, FutureBase]
cancelling: bool
logScope:
topics = "trackable futures"
proc len*(self: TrackedFutures): int = self.futures.len
proc removeFuture(self: TrackedFutures, future: FutureBase) =
if not self.cancelling and not future.isNil:
self.futures.del(future.id)
proc track*[T](self: TrackedFutures, fut: Future[T]): Future[T] =
if self.cancelling:
return fut
self.futures[fut.id] = FutureBase(fut)
fut
.then((val: T) => self.removeFuture(fut))
.cancelled(() => self.removeFuture(fut))
.catch((e: ref CatchableError) => self.removeFuture(fut))
return fut
proc track*[T, U](future: Future[T], self: U): Future[T] =
## Convenience method that allows chaining future, eg:
## `await someFut().track(sales)`, where `sales` has declared a
## `trackedFutures` property.
self.trackedFutures.track(future)
proc cancelTracked*(self: TrackedFutures) {.async.} =
self.cancelling = true
trace "cancelling tracked futures"
for future in self.futures.values:
if not future.isNil and not future.finished:
trace "cancelling tracked future", id = future.id
await future.cancelAndWait()
self.futures.clear()
self.cancelling = false