netty/src/main/java/io/grpc/netty/NettyServerStream.java

/*
 * Copyright 2014, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *    * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *
 *    * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package io.grpc.netty;

import static com.google.common.base.Preconditions.checkNotNull;

import io.grpc.Attributes;
import io.grpc.Metadata;
import io.grpc.Status;
import io.grpc.internal.AbstractServerStream;
import io.grpc.internal.WritableBuffer;
import io.netty.buffer.ByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.handler.codec.http2.Http2Headers;
import io.netty.handler.codec.http2.Http2Stream;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Server stream for a Netty HTTP2 transport. Must only be called from the sending application
 * thread.
 */
class NettyServerStream extends AbstractServerStream {
  private static final Logger log = Logger.getLogger(NettyServerStream.class.getName());

  private final Sink sink = new Sink();
  private final TransportState state;
  private final Channel channel;
  private final WriteQueue writeQueue;
  private final Attributes attributes;

  public NettyServerStream(Channel channel, TransportState state, Attributes transportAttrs) {
    super(new NettyWritableBufferAllocator(channel.alloc()));
    this.state = checkNotNull(state, "transportState");
    this.channel = checkNotNull(channel, "channel");
    this.writeQueue = state.handler.getWriteQueue();
    this.attributes = checkNotNull(transportAttrs);
  }

  @Override
  protected TransportState transportState() {
    return state;
  }

  @Override
  protected Sink abstractServerStreamSink() {
    return sink;
  }

  @Override public Attributes attributes() {
    return attributes;
  }

  private class Sink implements AbstractServerStream.Sink {
    @Override
    public void request(final int numMessages) {
      if (channel.eventLoop().inEventLoop()) {
        // Processing data read in the event loop so can call into the deframer immediately
        transportState().requestMessagesFromDeframer(numMessages);
      } else {
        writeQueue.enqueue(new RequestMessagesCommand(transportState(), numMessages), true);
      }
    }

    @Override
    public void writeHeaders(Metadata headers) {
      writeQueue.enqueue(new SendResponseHeadersCommand(transportState(),
          Utils.convertServerHeaders(headers), false),
          true);
    }

    @Override
    public void writeFrame(WritableBuffer frame, boolean flush) {
      if (frame == null) {
        writeQueue.scheduleFlush();
        return;
      }
      ByteBuf bytebuf = ((NettyWritableBuffer) frame).bytebuf();
      final int numBytes = bytebuf.readableBytes();
      // Add the bytes to outbound flow control.
      onSendingBytes(numBytes);
      writeQueue.enqueue(
          new SendGrpcFrameCommand(transportState(), bytebuf, false),
          channel.newPromise().addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
              // Remove the bytes from outbound flow control, optionally notifying
              // the client that they can send more bytes.
              transportState().onSentBytes(numBytes);
            }
          }), flush);
    }

    @Override
    public void writeTrailers(Metadata trailers, boolean headersSent) {
      Http2Headers http2Trailers = Utils.convertTrailers(trailers, headersSent);
      writeQueue.enqueue(
          new SendResponseHeadersCommand(transportState(), http2Trailers, true), true);
    }

    @Override
    public void cancel(Status status) {
      writeQueue.enqueue(new CancelServerStreamCommand(transportState(), status), true);
    }
  }

  /** This should only called from the transport thread. */
  public static class TransportState extends AbstractServerStream.TransportState
      implements StreamIdHolder {
    private final Http2Stream http2Stream;
    private final NettyServerHandler handler;

    public TransportState(NettyServerHandler handler, Http2Stream http2Stream, int maxMessageSize) {
      super(maxMessageSize);
      this.http2Stream = checkNotNull(http2Stream, "http2Stream");
      this.handler = checkNotNull(handler, "handler");
    }

    @Override
    public void bytesRead(int processedBytes) {
      handler.returnProcessedBytes(http2Stream, processedBytes);
      handler.getWriteQueue().scheduleFlush();
    }

    @Override
    protected void deframeFailed(Throwable cause) {
      log.log(Level.WARNING, "Exception processing message", cause);
      Status status = Status.fromThrowable(cause);
      transportReportStatus(status);
      handler.getWriteQueue().enqueue(new CancelServerStreamCommand(this, status), true);
    }

    void inboundDataReceived(ByteBuf frame, boolean endOfStream) {
      super.inboundDataReceived(new NettyReadableBuffer(frame.retain()), endOfStream);
    }

    @Override
    public int id() {
      return http2Stream.id();
    }
  }
}