content: /*
   * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package javac.internal.jimage.decompressor;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.nio.ByteOrder;
  import java.nio.charset.StandardCharsets;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Properties;
  import javac.internal.jimage.decompressor.ResourceDecompressor.StringsProvider;
  
  /**
   * Entry point to decompress resources.
   *
   * @implNote This class needs to maintain JDK 8 source compatibility.
   *
   * It is used internally in the JDK to implement jimage/jrtfs access,
   * but also compiled and delivered as part of the jrtfs.jar to support access
   * to the jimage file provided by the shipped JDK by tools running on JDK 8.
   */
  public final class Decompressor {
  
      private final Map<Integer, ResourceDecompressor> pluginsCache = new HashMap<>();
  
      public Decompressor() {
      }
  
      /**
       * Decompress a resource.
       * @param order Byte order.
       * @param provider Strings provider
       * @param content The resource content to uncompress.
       * @return A fully uncompressed resource.
       * @throws IOException
       */
      public byte[] decompressResource(ByteOrder order, StringsProvider provider,
              byte[] content) throws IOException {
          Objects.requireNonNull(order);
          Objects.requireNonNull(provider);
          Objects.requireNonNull(content);
          CompressedResourceHeader header;
          do {
              header = CompressedResourceHeader.readFromResource(order, content);
              if (header != null) {
                  ResourceDecompressor decompressor =
                          pluginsCache.get(header.getDecompressorNameOffset());
                  if (decompressor == null) {
                      String pluginName =
                              provider.getString(header.getDecompressorNameOffset());
                      if (pluginName == null) {
                          throw new IOException("Plugin name not found");
                      }
                      String storedContent = header.getStoredContent(provider);
                      Properties props = new Properties();
                      if (storedContent != null) {
                          try (ByteArrayInputStream stream
                                  = new ByteArrayInputStream(storedContent.
                                          getBytes(StandardCharsets.UTF_8));) {
                              props.loadFromXML(stream);
                          }
                      }
                      decompressor = ResourceDecompressorRepository.
                              newResourceDecompressor(props, pluginName);
                      if (decompressor == null) {
                          throw new IOException("Plugin not found: " + pluginName);
                      }
  
                      pluginsCache.put(header.getDecompressorNameOffset(), decompressor);
                  }
                  try {
                      content = decompressor.decompress(provider, content,
                              CompressedResourceHeader.getSize(), header.getUncompressedSize());
                  } catch (Exception ex) {
                      throw new IOException(ex);
                  }
              }
          } while (header != null);
          return content;
      }
  }
  