/*

 * Copyright 2020, 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

/// A handler that passes errors thrown into the server channel to the server error delegate.

///

/// A NIO server bootstrap produces two kinds of channels. The first and most common is the "child" channel:

/// each of these corresponds to one connection, and has the connection state stored on it. The other kind is

/// the "server" channel. Each bootstrap produces only one of these, and it is the channel that owns the listening

/// socket.

///

/// This channel handler is inserted into the server channel, and is responsible for passing any errors in that pipeline

/// to the server error delegate. If there is no error delegate, this handler is not inserted into the pipeline.

final class ServerChannelErrorHandler {

  private let errorDelegate: ServerErrorDelegate

  init(errorDelegate: ServerErrorDelegate) {

    self.errorDelegate = errorDelegate

  }

}

extension ServerChannelErrorHandler: ChannelInboundHandler {

  typealias InboundIn = Any

  typealias InboundOut = Any

  func errorCaught(context: ChannelHandlerContext, error: Error) {

    // This handler does not treat errors as fatal to the listening socket, as it's possible they were transiently

    // occurring in a single connection setup attempt.

    self.errorDelegate.observeLibraryError(error)

    context.fireErrorCaught(error)

  }

}