grpc-swift/Sources/GRPC/EventLoopFuture+RecoverFromUncleanShutdown.swift

/*
 * Copyright 2021, gRPC Authors All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import NIOCore
#if canImport(NIOSSL)
import NIOSSL
#endif

extension EventLoopFuture where Value == Void {
  internal func recoveringFromUncleanShutdown() -> EventLoopFuture<Void> {
    #if canImport(NIOSSL)
    // We can ignore unclean shutdown since gRPC is self-terminated and therefore not prone to
    // truncation attacks.
    return self.flatMapErrorThrowing { error in
      if let sslError = error as? NIOSSLError, sslError == .uncleanShutdown {
        ()
      } else {
        throw error
      }
    }
    #else
    return self
    #endif
  }
}