/*
    * Copyright 2015 The Netty Project
    *
    * The Netty Project 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:
    *
    * https://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 io.netty.handler.codec.http2;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.PooledByteBufAllocator;
  import io.netty.buffer.Unpooled;
  import io.netty.buffer.UnpooledByteBufAllocator;
  import io.netty.channel.ChannelFuture;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.channel.ChannelPromise;
  import io.netty.microbench.channel.EmbeddedChannelWriteReleaseHandlerContext;
  import io.netty.microbench.util.AbstractMicrobenchmark;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.BenchmarkMode;
  import org.openjdk.jmh.annotations.Fork;
  import org.openjdk.jmh.annotations.Level;
  import org.openjdk.jmh.annotations.Measurement;
  import org.openjdk.jmh.annotations.Mode;
  import org.openjdk.jmh.annotations.OutputTimeUnit;
  import org.openjdk.jmh.annotations.Param;
  import org.openjdk.jmh.annotations.Scope;
  import org.openjdk.jmh.annotations.Setup;
  import org.openjdk.jmh.annotations.State;
  import org.openjdk.jmh.annotations.TearDown;
  import org.openjdk.jmh.annotations.Warmup;
  
  import java.util.concurrent.TimeUnit;
  
  import static io.netty.buffer.Unpooled.directBuffer;
  import static io.netty.buffer.Unpooled.unreleasableBuffer;
  import static io.netty.handler.codec.http2.Http2CodecUtil.DATA_FRAME_HEADER_LENGTH;
  import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_MAX_FRAME_SIZE;
  import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_UNSIGNED_BYTE;
  import static io.netty.handler.codec.http2.Http2CodecUtil.verifyPadding;
  import static io.netty.handler.codec.http2.Http2CodecUtil.writeFrameHeaderInternal;
  import static io.netty.handler.codec.http2.Http2FrameTypes.DATA;
  import static io.netty.util.internal.ObjectUtil.checkPositive;
  import static java.lang.Math.max;
  import static java.lang.Math.min;
  
  @Fork(1)
  @Warmup(iterations = 5)
  @Measurement(iterations = 5)
  @State(Scope.Benchmark)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  public class Http2FrameWriterDataBenchmark extends AbstractMicrobenchmark {
      @Param({ "64", "1024", "4096", "16384", "1048576", "4194304" })
      public int payloadSize;
  
      @Param({ "0", "100", "255" })
      public int padding;
  
      @Param({ "true", "false" })
      public boolean pooled;
  
      private ByteBuf payload;
      private ChannelHandlerContext ctx;
      private Http2DataWriter writer;
      private Http2DataWriter oldWriter;
  
      @Setup(Level.Trial)
      public void setup() {
          writer = new DefaultHttp2FrameWriter();
          oldWriter = new OldDefaultHttp2FrameWriter();
          payload = pooled ? PooledByteBufAllocator.DEFAULT.buffer(payloadSize) : Unpooled.buffer(payloadSize);
          payload.writeZero(payloadSize);
          ctx = new EmbeddedChannelWriteReleaseHandlerContext(
                  pooled ? PooledByteBufAllocator.DEFAULT : UnpooledByteBufAllocator.DEFAULT,
                  new ChannelInboundHandlerAdapter()) {
              @Override
              protected void handleException(Throwable t) {
                  handleUnexpectedException(t);
              }
          };
      }
  
      @TearDown(Level.Trial)
      public void teardown() throws Exception {
          if (payload != null) {
              payload.release();
          }
          if (ctx != null) {
              ctx.close();
          }
      }
 
     @Benchmark
     @BenchmarkMode(Mode.AverageTime)
     public void newWriter() {
         writer.writeData(ctx, 3, payload.retain(), padding, true, ctx.voidPromise());
         ctx.flush();
     }
 
     @Benchmark
     @BenchmarkMode(Mode.AverageTime)
     public void oldWriter() {
         oldWriter.writeData(ctx, 3, payload.retain(), padding, true, ctx.voidPromise());
         ctx.flush();
     }
 
     private static final class OldDefaultHttp2FrameWriter implements Http2DataWriter {
         private static final ByteBuf ZERO_BUFFER =
                 unreleasableBuffer(directBuffer(MAX_UNSIGNED_BYTE).writeZero(MAX_UNSIGNED_BYTE)).asReadOnly();
         private final int maxFrameSize = DEFAULT_MAX_FRAME_SIZE;
         @Override
         public ChannelFuture writeData(ChannelHandlerContext ctx, int streamId, ByteBuf data,
                                        int padding, boolean endStream, ChannelPromise promise) {
             final Http2CodecUtil.SimpleChannelPromiseAggregator promiseAggregator =
                     new Http2CodecUtil.SimpleChannelPromiseAggregator(promise, ctx.channel(), ctx.executor());
             final DataFrameHeader header = new DataFrameHeader(ctx, streamId);
             boolean needToReleaseHeaders = true;
             boolean needToReleaseData = true;
             try {
                 checkPositive(streamId, "streamId");
                 verifyPadding(padding);
 
                 boolean lastFrame;
                 int remainingData = data.readableBytes();
                 do {
                     // Determine how much data and padding to write in this frame. Put all padding at the end.
                     int frameDataBytes = min(remainingData, maxFrameSize);
                     int framePaddingBytes = min(padding, max(0, (maxFrameSize - 1) - frameDataBytes));
 
                     // Decrement the remaining counters.
                     padding -= framePaddingBytes;
                     remainingData -= frameDataBytes;
 
                     // Determine whether or not this is the last frame to be sent.
                     lastFrame = remainingData == 0 && padding == 0;
 
                     // Only the last frame is not retained. Until then, the outer finally must release.
                     ByteBuf frameHeader = header.slice(frameDataBytes, framePaddingBytes, lastFrame && endStream);
                     needToReleaseHeaders = !lastFrame;
                     ctx.write(lastFrame ? frameHeader : frameHeader.retain(), promiseAggregator.newPromise());
 
                     // Write the frame data.
                     ByteBuf frameData = data.readSlice(frameDataBytes);
                     // Only the last frame is not retained. Until then, the outer finally must release.
                     needToReleaseData = !lastFrame;
                     ctx.write(lastFrame ? frameData : frameData.retain(), promiseAggregator.newPromise());
 
                     // Write the frame padding.
                     if (paddingBytes(framePaddingBytes) > 0) {
                         ctx.write(ZERO_BUFFER.slice(0, paddingBytes(framePaddingBytes)),
                                 promiseAggregator.newPromise());
                     }
                 } while (!lastFrame);
             } catch (Throwable t) {
                 try {
                     if (needToReleaseHeaders) {
                         header.release();
                     }
                     if (needToReleaseData) {
                         data.release();
                     }
                 } finally {
                     promiseAggregator.setFailure(t);
                     promiseAggregator.doneAllocatingPromises();
                 }
                 return promiseAggregator;
             }
             return promiseAggregator.doneAllocatingPromises();
         }
 
         private static int paddingBytes(int padding) {
             // The padding parameter contains the 1 byte pad length field as well as the trailing padding bytes.
             // Subtract 1, so to only get the number of padding bytes that need to be appended to the end of a frame.
             return padding - 1;
         }
 
         private static void writePaddingLength(ByteBuf buf, int padding) {
             if (padding > 0) {
                 // It is assumed that the padding length has been bounds checked before this
                 // Minus 1, as the pad length field is included in the padding parameter and is 1 byte wide.
                 buf.writeByte(padding - 1);
             }
         }
 
         /**
          * Utility class that manages the creation of frame header buffers for {@code DATA} frames. Attempts
          * to reuse the same buffer repeatedly when splitting data into multiple frames.
          */
         private static final class DataFrameHeader {
             private final int streamId;
             private final ByteBuf buffer;
             private final Http2Flags flags = new Http2Flags();
             private int prevData;
             private int prevPadding;
             private ByteBuf frameHeader;
 
             DataFrameHeader(ChannelHandlerContext ctx, int streamId) {
                 // All padding will be put at the end, so in the worst case we need 3 headers:
                 // a repeated no-padding frame of maxFrameSize, a frame that has part data and part
                 // padding, and a frame that has the remainder of the padding.
                 buffer = ctx.alloc().buffer(3 * DATA_FRAME_HEADER_LENGTH);
                 this.streamId = streamId;
             }
 
             /**
              * Gets the frame header buffer configured for the current frame.
              */
             ByteBuf slice(int data, int padding, boolean endOfStream) {
                 // Since we're reusing the current frame header whenever possible, check if anything changed
                 // that requires a new header.
                 if (data != prevData || padding != prevPadding
                         || endOfStream != flags.endOfStream() || frameHeader == null) {
                     // Update the header state.
                     prevData = data;
                     prevPadding = padding;
                     flags.paddingPresent(padding > 0);
                     flags.endOfStream(endOfStream);
                     frameHeader = buffer.slice(buffer.readerIndex(), DATA_FRAME_HEADER_LENGTH).writerIndex(0);
                     buffer.setIndex(buffer.readerIndex() + DATA_FRAME_HEADER_LENGTH,
                             buffer.writerIndex() + DATA_FRAME_HEADER_LENGTH);
 
                     int payloadLength = data + padding;
                     writeFrameHeaderInternal(frameHeader, payloadLength, DATA, flags, streamId);
                     writePaddingLength(frameHeader, padding);
                 }
                 return frameHeader.slice();
             }
 
             void release() {
                 buffer.release();
             }
         }
     }
 }