Class MessageDeframer

core/src/main/java/io/grpc/internal/MessageDeframer.java:42–550

Deframer for GRPC frames. This class is not thread-safe. Unless otherwise stated, all calls to public methods should be made in the deframing thread.

 * made in the deframing thread.
 */
@NotThreadSafe
public class MessageDeframer implements Closeable, Deframer {
  private static final int HEADER_LENGTH = 5;
  private static final int COMPRESSED_FLAG_MASK = 1;
  private static final int RESERVED_MASK = 0xFE;
  private static final int MAX_BUFFER_SIZE = 1024 * 1024 * 2;

  /**
   * A listener of deframing events. These methods will be invoked from the deframing thread.
   */
  public interface Listener {

    /**
     * Called when the given number of bytes has been read from the input source of the deframer.
     * This is typically used to indicate to the underlying transport that more data can be
     * accepted.
     *
     * @param numBytes the number of bytes read from the deframer's input source.
     */
    void bytesRead(int numBytes);

    /**
     * Called to deliver the next complete message.
     *
     * @param producer single message producer wrapping the message.
     */
    void messagesAvailable(StreamListener.MessageProducer producer);

    /**
     * Called when the deframer closes.
     *
     * @param hasPartialMessage whether the deframer contained an incomplete message at closing.
     */
    void deframerClosed(boolean hasPartialMessage);

    /**
     * Called when a {@link #deframe(ReadableBuffer)} operation failed.
     *
     * @param cause the actual failure
     */
    void deframeFailed(Throwable cause);
  }

  private enum State {
    HEADER, BODY
  }

  private Listener listener;
  private int maxInboundMessageSize;
  private final StatsTraceContext statsTraceCtx;
  private final TransportTracer transportTracer;
  private Decompressor decompressor;
  private GzipInflatingBuffer fullStreamDecompressor;
  private byte[] inflatedBuffer;
  private int inflatedIndex;
  private State state = State.HEADER;
  private int requiredLength = HEADER_LENGTH;
  private boolean compressedFlag;