/*
    * junixsocket
    *
    * Copyright 2009-2024 Christian Kohlschütter
    *
    * 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.
   */
  package org.newsclub.net.unix.demo.client;
  
  import java.io.FileDescriptor;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.Socket;
  
  import org.newsclub.net.unix.AFUNIXSocket;
  
  /**
   * A client that reads the contents of file descriptors that are sent as ancillary messages.
   *
   * The actual in-band data that is received is silently ignored.
   */
  public class ReadFileHandleClient extends DemoClientBase {
    @Override
    protected void handleSocket(Socket socket) throws IOException {
      if (!(socket instanceof AFUNIXSocket)) {
        throw new UnsupportedOperationException("File handles can only be sent via UNIX sockets");
      }
      handleSocket((AFUNIXSocket) socket);
    }
  
    protected void handleSocket(AFUNIXSocket socket) throws IOException {
      // set to a reasonable size
      socket.setAncillaryReceiveBufferSize(1024);
  
      try (InputStream in = socket.getInputStream()) {
        byte[] buf = new byte[socket.getReceiveBufferSize()];
  
        while (in.read(buf) != -1) {
          FileDescriptor[] descriptors = socket.getReceivedFileDescriptors();
          if (descriptors != null) {
            for (FileDescriptor fd : descriptors) {
              handleFileDescriptor(fd);
            }
          }
        }
      }
    }
  
    private void handleFileDescriptor(FileDescriptor fd) throws IOException {
      try (FileInputStream fin = new FileInputStream(fd)) {
        byte[] buf = new byte[4096];
        int read;
        while ((read = fin.read(buf)) != -1) {
          System.out.write(buf, 0, read);
        }
        System.out.flush();
      }
    }
  }