org.apache.flink.runtime.io.network.netty.OutboundEnvelopeEncoder.java Source code

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Here is the source code for org.apache.flink.runtime.io.network.netty.OutboundEnvelopeEncoder.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.runtime.io.network.netty;

import org.apache.flink.runtime.io.network.Buffer;
import org.apache.flink.runtime.io.network.Envelope;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOutboundHandlerAdapter;
import io.netty.channel.ChannelPromise;

@ChannelHandler.Sharable
public class OutboundEnvelopeEncoder extends ChannelOutboundHandlerAdapter {

    public static final int HEADER_SIZE = 48;

    public static final int MAGIC_NUMBER = 0xBADC0FFE;

    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
        Envelope env = (Envelope) msg;

        ByteBuf buf = ctx.alloc().directBuffer();

        encode(env, buf);

        if (buf.isReadable()) {
            ctx.write(buf, promise);
        } else {
            buf.release();
            ctx.write(Unpooled.EMPTY_BUFFER, promise);
        }
    }

    private void encode(Envelope env, ByteBuf out) {
        // --------------------------------------------------------------------
        // (1) header (48 bytes)
        // --------------------------------------------------------------------
        out.writeInt(MAGIC_NUMBER); // 4 bytes

        if (out.getInt(out.writerIndex() - 4) != MAGIC_NUMBER) {
            throw new RuntimeException();
        }

        out.writeInt(env.getSequenceNumber()); // 4 bytes
        env.getJobID().writeTo(out); // 16 bytes
        env.getSource().writeTo(out); // 16 bytes
        out.writeInt(env.getEventsSerialized() != null ? env.getEventsSerialized().remaining() : 0); // 4 bytes
        out.writeInt(env.getBuffer() != null ? env.getBuffer().size() : 0); // 4 bytes
        // --------------------------------------------------------------------
        // (2) events (var length)
        // --------------------------------------------------------------------
        if (env.getEventsSerialized() != null) {
            out.writeBytes(env.getEventsSerialized());
        }

        // --------------------------------------------------------------------
        // (3) buffer (var length)
        // --------------------------------------------------------------------
        if (env.getBuffer() != null) {
            Buffer envBuffer = env.getBuffer();
            out.writeBytes(envBuffer.getMemorySegment().wrap(0, envBuffer.size()));

            // Recycle the buffer from OUR buffer pool after everything has been
            // copied to Nettys buffer space.
            envBuffer.recycleBuffer();
        }
    }
}