nim-libp2p/libp2p/utils/future.nim

# Nim-Libp2p
# Copyright (c) 2023 Status Research & Development GmbH
# Licensed under either of
#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
# at your option.
# This file may not be copied, modified, or distributed except according to
# those terms.

{.push raises: [].}

import chronos

type
  AllFuturesFailedError* = object of CatchableError

proc anyCompleted*[T](futs: seq[Future[T]]): Future[Future[T]] {.async.} =
  ## Returns a future that will complete with the first future that completes.
  ## If all futures fail or futs is empty, the returned future will fail with AllFuturesFailedError.

  var requests = futs

  while true:
    if requests.len == 0:
      raise newException(AllFuturesFailedError, "None of the futures completed successfully")

    var raceFut = await one(requests)
    if raceFut.completed:
      return raceFut

    let index = requests.find(raceFut)
    requests.del(index)