content: /*
   * Copyright (c) 2020, 2021, Oracle and/or its affiliates.
   *
   * This program is free software; you can redistribute it and/or modify it under
   * the terms of the GNU General Public License, version 2.0, as published by the
   * Free Software Foundation.
   *
   * This program is also distributed with certain software (including but not
   * limited to OpenSSL) that is licensed under separate terms, as designated in a
   * particular file or component or in included license documentation. The
   * authors of MySQL hereby grant you an additional permission to link the
   * program and your derivative works with the separately licensed software that
   * they have included with MySQL.
   *
   * Without limiting anything contained in the foregoing, this file, which is
   * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
   * version 1.0, a copy of which can be found at
   * http://oss.oracle.com/licenses/universal-foss-exception.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   * FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
   * for more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
   */
  
  package com.mysql.cj.protocol.x;
  
  import java.io.InputStream;
  import java.io.OutputStream;
  
  import com.mysql.cj.Messages;
  import com.mysql.cj.util.Util;
  
  /**
   * Factory class for producing inflating and deflating-able {@link InputStream} and {@link OutputStream} instances for a selected compression algorithm.
   */
  public class CompressorStreamsFactory {
      private CompressionAlgorithm compressionAlgorithm;
  
      private InputStream compressorInputStreamInstance = null;
      private ContinuousInputStream underlyingInputStream = null;
  
      private OutputStream compressorOutputStreamInstance = null;
      private ReusableOutputStream underlyingOutputStream = null;
  
      public CompressorStreamsFactory(CompressionAlgorithm algorithm) {
          this.compressionAlgorithm = algorithm;
      }
  
      public CompressionMode getCompressionMode() {
          return this.compressionAlgorithm.getCompressionMode();
      }
  
      public boolean areCompressedStreamsContinuous() {
          return getCompressionMode() == CompressionMode.STREAM;
      }
  
      /**
       * Creates an instance of an {@link InputStream} that wraps around the given {@link InputStream} and knows how to inflate data using the algorithm given in
       * this class' constructor.
       * 
       * If the compression algorithm operates in steam mode (continuous) then create and reuse one single instance of the compressor {@link InputStream}, else
       * create a new instance every time.
       * 
       * @param in
       *            the {@link InputStream} to use as source of the bytes to inflate.
       * @return
       *         the new inflater {@link InputStream} wrapper instance.
       */
      public InputStream getInputStreamInstance(InputStream in) {
          InputStream underlyingIn = in;
  
          if (areCompressedStreamsContinuous()) {
              if (this.compressorInputStreamInstance != null) {
                  this.underlyingInputStream.addInputStream(underlyingIn);
                  return this.compressorInputStreamInstance;
              }
              this.underlyingInputStream = new ContinuousInputStream(underlyingIn);
              underlyingIn = this.underlyingInputStream;
          }
  
          InputStream compressionIn = (InputStream) Util.getInstance(this.compressionAlgorithm.getInputStreamClass().getName(),
                  new Class<?>[] { InputStream.class }, new Object[] { underlyingIn }, null, Messages.getString("Protocol.Compression.IoFactory.0",
                          new Object[] { this.compressionAlgorithm.getInputStreamClass().getName(), this.compressionAlgorithm }));
  
          if (areCompressedStreamsContinuous()) {
              this.compressorInputStreamInstance = compressionIn;
          }
          return compressionIn;
      }
  
      /**
       * Creates an instance of an {@link OutputStream} that wraps around the given {@link OutputStream} and knows how to deflate data using the algorithm given
       * in this class' constructor.
       * 
       * If the compression algorithm operates in steam mode (continuous) then create and reuse one single instance of the compressor {@link OutputStream}, else
       * create a new instance every time.
       * 
       * @param out
       *            the {@link OutputStream} to use as target of the bytes to deflate.
       * @return
       *         the new deflater {@link OutputStream} wrapper instance.
       */
      public OutputStream getOutputStreamInstance(OutputStream out) {
          OutputStream underlyingOut = out;
  
          if (areCompressedStreamsContinuous()) {
              if (this.compressorOutputStreamInstance != null) {
                  this.underlyingOutputStream.setOutputStream(underlyingOut);
                  return this.compressorOutputStreamInstance;
              }
              this.underlyingOutputStream = new ReusableOutputStream(underlyingOut);
              underlyingOut = this.underlyingOutputStream;
          }
  
          OutputStream compressionOut = (OutputStream) Util.getInstance(this.compressionAlgorithm.getOutputStreamClass().getName(),
                  new Class<?>[] { OutputStream.class }, new Object[] { underlyingOut }, null, Messages.getString("Protocol.Compression.IoFactory.1",
                          new Object[] { this.compressionAlgorithm.getOutputStreamClass().getName(), this.compressionAlgorithm }));
  
          if (areCompressedStreamsContinuous()) {
              compressionOut = new ContinuousOutputStream(compressionOut);
              this.compressorOutputStreamInstance = compressionOut;
          }
          return compressionOut;
      }
  }
  