gistfile1.scala

  private def metaExists(id: Id[DocumentMeta]): Rx[Boolean] = {
    metaDir.fileExists(id.value) mapToRx {
      case Failure(_) => false
      case Success(exists) => exists
    }
  }

  private def dataExists(id: Id[DocumentMeta]): Rx[Boolean] = {
    dir.fileExists(id.value) mapToRx {
      case Failure(_) => false
      case Success(exists) => exists
    }
  }

  private def getPendingMeta(id: Id[DocumentMeta])(f: => Rx[CdnMetaState]) = {
    pendingMeta.getOrElseUpdate(id, f)
  }

  private def getPendingData(id: Id[DocumentMeta])(f: => Rx[CdnDataState]) = {
    pendingData.getOrElseUpdate(id, f)
  }