content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * 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 com.google.android.exoplayer2.upstream;
  
  import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
  import static java.lang.Math.min;
  
  import android.net.Uri;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.PlaybackException;
  import java.io.IOException;
  import java.net.DatagramPacket;
  import java.net.DatagramSocket;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.MulticastSocket;
  import java.net.SocketTimeoutException;
  
  /** A UDP {@link DataSource}. */
  public final class UdpDataSource extends BaseDataSource {
  
    /** Thrown when an error is encountered when trying to read from a {@link UdpDataSource}. */
    public static final class UdpDataSourceException extends DataSourceException {
  
      /**
       * Creates a {@code UdpDataSourceException}.
       *
       * @param cause The error cause.
       * @param errorCode Reason of the error, should be one of the {@code ERROR_CODE_IO_*} in {@link
       *     PlaybackException.ErrorCode}.
       */
      public UdpDataSourceException(Throwable cause, @PlaybackException.ErrorCode int errorCode) {
        super(cause, errorCode);
      }
    }
  
    /** The default maximum datagram packet size, in bytes. */
    public static final int DEFAULT_MAX_PACKET_SIZE = 2000;
  
    /** The default socket timeout, in milliseconds. */
    public static final int DEFAULT_SOCKET_TIMEOUT_MILLIS = 8 * 1000;
  
    public static final int UDP_PORT_UNSET = -1;
  
    private final int socketTimeoutMillis;
    private final byte[] packetBuffer;
    private final DatagramPacket packet;
  
    @Nullable private Uri uri;
    @Nullable private DatagramSocket socket;
    @Nullable private MulticastSocket multicastSocket;
    @Nullable private InetAddress address;
    private boolean opened;
  
    private int packetRemaining;
  
    public UdpDataSource() {
      this(DEFAULT_MAX_PACKET_SIZE);
    }
  
    /**
     * Constructs a new instance.
     *
     * @param maxPacketSize The maximum datagram packet size, in bytes.
     */
    public UdpDataSource(int maxPacketSize) {
      this(maxPacketSize, DEFAULT_SOCKET_TIMEOUT_MILLIS);
    }
  
    /**
     * Constructs a new instance.
     *
     * @param maxPacketSize The maximum datagram packet size, in bytes.
     * @param socketTimeoutMillis The socket timeout in milliseconds. A timeout of zero is interpreted
     *     as an infinite timeout.
     */
    public UdpDataSource(int maxPacketSize, int socketTimeoutMillis) {
      super(/* isNetwork= */ true);
      this.socketTimeoutMillis = socketTimeoutMillis;
      packetBuffer = new byte[maxPacketSize];
      packet = new DatagramPacket(packetBuffer, 0, maxPacketSize);
    }
  
    @Override
    public long open(DataSpec dataSpec) throws UdpDataSourceException {
      uri = dataSpec.uri;
      String host = checkNotNull(uri.getHost());
      int port = uri.getPort();
      transferInitializing(dataSpec);
      try {
        address = InetAddress.getByName(host);
        InetSocketAddress socketAddress = new InetSocketAddress(address, port);
        if (address.isMulticastAddress()) {
          multicastSocket = new MulticastSocket(socketAddress);
          multicastSocket.joinGroup(address);
          socket = multicastSocket;
        } else {
          socket = new DatagramSocket(socketAddress);
        }
        socket.setSoTimeout(socketTimeoutMillis);
      } catch (SecurityException e) {
        throw new UdpDataSourceException(e, PlaybackException.ERROR_CODE_IO_NO_PERMISSION);
      } catch (IOException e) {
        throw new UdpDataSourceException(
            e, PlaybackException.ERROR_CODE_IO_NETWORK_CONNECTION_FAILED);
      }
  
      opened = true;
      transferStarted(dataSpec);
      return C.LENGTH_UNSET;
    }
  
    @Override
    public int read(byte[] buffer, int offset, int length) throws UdpDataSourceException {
      if (length == 0) {
        return 0;
      }
  
      if (packetRemaining == 0) {
        // We've read all of the data from the current packet. Get another.
        try {
          checkNotNull(socket).receive(packet);
        } catch (SocketTimeoutException e) {
          throw new UdpDataSourceException(
              e, PlaybackException.ERROR_CODE_IO_NETWORK_CONNECTION_TIMEOUT);
        } catch (IOException e) {
          throw new UdpDataSourceException(
              e, PlaybackException.ERROR_CODE_IO_NETWORK_CONNECTION_FAILED);
        }
        packetRemaining = packet.getLength();
        bytesTransferred(packetRemaining);
      }
  
      int packetOffset = packet.getLength() - packetRemaining;
      int bytesToRead = min(packetRemaining, length);
      System.arraycopy(packetBuffer, packetOffset, buffer, offset, bytesToRead);
      packetRemaining -= bytesToRead;
      return bytesToRead;
    }
  
    @Override
    @Nullable
    public Uri getUri() {
      return uri;
    }
  
    @Override
    public void close() {
      uri = null;
      if (multicastSocket != null) {
        try {
          multicastSocket.leaveGroup(checkNotNull(address));
        } catch (IOException e) {
          // Do nothing.
        }
        multicastSocket = null;
      }
      if (socket != null) {
        socket.close();
        socket = null;
      }
      address = null;
      packetRemaining = 0;
      if (opened) {
        opened = false;
        transferEnded();
      }
    }
  
    /**
     * Returns the local port number opened for the UDP connection, or {@link #UDP_PORT_UNSET} if no
     * connection is open
     */
    public int getLocalPort() {
      if (socket == null) {
        return UDP_PORT_UNSET;
      }
      return socket.getLocalPort();
    }
  }
  