io.youi.Blocked.scala Maven / Gradle / Ivy

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Core functionality leveraged and shared by most other sub-projects of YouI.

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package io.youi

import scala.concurrent.{Future, Promise}
import scribe.Execution.global

object Blocked {
  var enabled: Boolean = true

  private var map = Map.empty[Any, Future[_]]

  def apply[Result](keys: Any*)(f: => Future[Result]): Future[Result] = if (enabled) {
    synchronized {
      val previous = Future.sequence(keys.map(map.getOrElse(_, Future.successful(()))))
      val future = if (previous.isCompleted) {
        f
      } else {
        val promise = Promise[Result]
        previous.onComplete { _ =>
          val next: Future[Result] = f
          next.onComplete(promise.complete)
        }
        promise.future
      }

      keys.foreach { key =>
        map += key -> future
      }
      future
    }
  } else {
    f
  }
}