content: /*
   * 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 com.datastax.oss.driver.internal.core.protocol;
  
  import com.datastax.oss.driver.api.core.context.DriverContext;
  import com.datastax.oss.driver.internal.core.util.DefaultDependencyChecker;
  import com.datastax.oss.driver.internal.core.util.Dependency;
  import io.netty.buffer.ByteBuf;
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import net.jcip.annotations.ThreadSafe;
  import org.xerial.snappy.Snappy;
  
  /**
   * @implNote The Snappy protocol already encodes the uncompressed length in the compressed payload,
   *     so {@link #compress(ByteBuf)} and {@link #compressWithoutLength(ByteBuf)} produce the same
   *     output for this compressor. The corresponding parameters {@code
   *     prependWithUncompressedLength} and {@code uncompressedLength} are ignored by their respective
   *     methods.
   */
  @ThreadSafe
  public class SnappyCompressor extends ByteBufCompressor {
  
    public SnappyCompressor(@SuppressWarnings("unused") DriverContext context) {
      if (!DefaultDependencyChecker.isPresent(Dependency.SNAPPY)) {
        throw new IllegalStateException(
            "Could not find the Snappy library on the classpath "
                + "(the driver declares it as an optional dependency, "
                + "so you need to declare it explicitly)");
      }
    }
  
    @Override
    public String algorithm() {
      return "snappy";
    }
  
    @Override
    protected ByteBuf compressDirect(
        ByteBuf input, /*ignored*/ boolean prependWithUncompressedLength) {
      int maxCompressedLength = Snappy.maxCompressedLength(input.readableBytes());
      // If the input is direct we will allocate a direct output buffer as well as this will allow us
      // to use Snappy.compress(ByteBuffer, ByteBuffer) and so eliminate memory copies.
      ByteBuf output = input.alloc().directBuffer(maxCompressedLength);
      try {
        ByteBuffer in = inputNioBuffer(input);
        // Increase reader index.
        input.readerIndex(input.writerIndex());
  
        ByteBuffer out = outputNioBuffer(output);
        int written = Snappy.compress(in, out);
        // Set the writer index so the amount of written bytes is reflected
        output.writerIndex(output.writerIndex() + written);
        return output;
      } catch (IOException e) {
        // release output buffer so we not leak and rethrow exception.
        output.release();
        throw new RuntimeException(e);
      }
    }
  
    @Override
    protected ByteBuf compressHeap(ByteBuf input, /*ignored*/ boolean prependWithUncompressedLength) {
      int maxCompressedLength = Snappy.maxCompressedLength(input.readableBytes());
      int inOffset = input.arrayOffset() + input.readerIndex();
      byte[] in = input.array();
      int len = input.readableBytes();
      // Increase reader index.
      input.readerIndex(input.writerIndex());
  
      // Allocate a heap buffer from the ByteBufAllocator as we may use a PooledByteBufAllocator and
      // so can eliminate the overhead of allocate a new byte[].
      ByteBuf output = input.alloc().heapBuffer(maxCompressedLength);
      try {
        // Calculate the correct offset.
        int offset = output.arrayOffset() + output.writerIndex();
        byte[] out = output.array();
        int written = Snappy.compress(in, inOffset, len, out, offset);
  
        // Increase the writerIndex with the written bytes.
        output.writerIndex(output.writerIndex() + written);
        return output;
      } catch (IOException e) {
        // release output buffer so we not leak and rethrow exception.
        output.release();
        throw new RuntimeException(e);
      }
    }
  
    @Override
    protected int readUncompressedLength(ByteBuf compressed) {
      // Since compress methods don't actually prepend with a length, we have nothing to read here.
      // Return a bogus length (it will be ignored by the decompress methods, so the actual value
      // doesn't matter).
      return -1;
    }
  
    @Override
    protected ByteBuf decompressDirect(ByteBuf input, /*ignored*/ int uncompressedLength) {
      ByteBuffer in = inputNioBuffer(input);
      // Increase reader index.
      input.readerIndex(input.writerIndex());
  
      ByteBuf output = null;
      try {
        if (!Snappy.isValidCompressedBuffer(in)) {
          throw new IllegalArgumentException(
              "Provided frame does not appear to be Snappy compressed");
        }
        // If the input is direct we will allocate a direct output buffer as well as this will allow
        // us to use Snappy.compress(ByteBuffer, ByteBuffer) and so eliminate memory copies.
        output = input.alloc().directBuffer(Snappy.uncompressedLength(in));
        ByteBuffer out = outputNioBuffer(output);
  
        int size = Snappy.uncompress(in, out);
        // Set the writer index so the amount of written bytes is reflected
        output.writerIndex(output.writerIndex() + size);
        return output;
      } catch (IOException e) {
        // release output buffer so we not leak and rethrow exception.
        if (output != null) {
          output.release();
        }
        throw new RuntimeException(e);
      }
    }
  
    @Override
    protected ByteBuf decompressHeap(ByteBuf input, /*ignored*/ int uncompressedLength) {
      // Not a direct buffer so use byte arrays...
      int inOffset = input.arrayOffset() + input.readerIndex();
      byte[] in = input.array();
      int len = input.readableBytes();
      // Increase reader index.
      input.readerIndex(input.writerIndex());
  
      ByteBuf output = null;
      try {
        if (!Snappy.isValidCompressedBuffer(in, inOffset, len)) {
          throw new IllegalArgumentException(
              "Provided frame does not appear to be Snappy compressed");
        }
        // Allocate a heap buffer from the ByteBufAllocator as we may use a PooledByteBufAllocator and
        // so can eliminate the overhead of allocate a new byte[].
        output = input.alloc().heapBuffer(Snappy.uncompressedLength(in, inOffset, len));
        // Calculate the correct offset.
        int offset = output.arrayOffset() + output.writerIndex();
        byte[] out = output.array();
        int written = Snappy.uncompress(in, inOffset, len, out, offset);
  
        // Increase the writerIndex with the written bytes.
        output.writerIndex(output.writerIndex() + written);
        return output;
      } catch (IOException e) {
        // release output buffer so we not leak and rethrow exception.
        if (output != null) {
          output.release();
        }
        throw new RuntimeException(e);
      }
    }
  }
  