/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.client5.http.impl.cache;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.ObjectStreamClass;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.regex.Pattern;
  
  import org.apache.hc.client5.http.cache.HttpCacheEntrySerializer;
  import org.apache.hc.client5.http.cache.HttpCacheStorageEntry;
  import org.apache.hc.client5.http.cache.ResourceIOException;
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  
  /**
   * {@link HttpCacheEntrySerializer} implementation that uses the default (native)
   * serialization.
   *
   * @see java.io.Serializable
   *
   * @since 4.1
   */
  @Contract(threading = ThreadingBehavior.STATELESS)
  public final class ByteArrayCacheEntrySerializer implements HttpCacheEntrySerializer<byte[]> {
  
      public static final ByteArrayCacheEntrySerializer INSTANCE = new ByteArrayCacheEntrySerializer();
  
      @Override
      public byte[] serialize(final HttpCacheStorageEntry cacheEntry) throws ResourceIOException {
          if (cacheEntry == null) {
              return null;
          }
          final ByteArrayOutputStream buf = new ByteArrayOutputStream();
          try (final ObjectOutputStream oos = new ObjectOutputStream(buf)) {
              oos.writeObject(cacheEntry);
          } catch (final IOException ex) {
              throw new ResourceIOException(ex.getMessage(), ex);
          }
          return buf.toByteArray();
      }
  
      @Override
      public HttpCacheStorageEntry deserialize(final byte[] serializedObject) throws ResourceIOException {
          if (serializedObject == null) {
              return null;
          }
          try (final ObjectInputStream ois = new RestrictedObjectInputStream(new ByteArrayInputStream(serializedObject))) {
              return (HttpCacheStorageEntry) ois.readObject();
          } catch (final IOException | ClassNotFoundException ex) {
              throw new ResourceIOException(ex.getMessage(), ex);
          }
      }
  
      // visible for testing
      static class RestrictedObjectInputStream extends ObjectInputStream {
  
          private static final List<Pattern> ALLOWED_CLASS_PATTERNS = Collections.unmodifiableList(Arrays.asList(
                  Pattern.compile("^(\\[L)?org\\.apache\\.hc\\.(.*)"),
                  Pattern.compile("^(?:\\[+L)?java\\.util\\..*$"),
                  Pattern.compile("^(?:\\[+L)?java\\.lang\\..*$"),
                  Pattern.compile("^(?:\\[+L)?java\\.time\\..*$"), // java 8 time
                  Pattern.compile("^\\[+Z$"), // boolean
                  Pattern.compile("^\\[+B$"), // byte
                  Pattern.compile("^\\[+C$"), // char
                  Pattern.compile("^\\[+D$"), // double
                  Pattern.compile("^\\[+F$"), // float
                  Pattern.compile("^\\[+I$"), // int
                 Pattern.compile("^\\[+J$"), // long
                 Pattern.compile("^\\[+S$") // short
         ));
 
         private RestrictedObjectInputStream(final InputStream in) throws IOException {
             super(in);
         }
 
         @Override
         protected Class<?> resolveClass(final ObjectStreamClass objectStreamClass) throws IOException, ClassNotFoundException {
             final String className = objectStreamClass.getName();
             if (!isAllowedClassName(className)) {
                 throw new ResourceIOException(String.format(
                         "Class %s is not allowed for deserialization", objectStreamClass.getName()));
             }
             return super.resolveClass(objectStreamClass);
         }
 
         // visible for testing
         static boolean isAllowedClassName(final String className) {
             for (final Pattern allowedClassPattern : ALLOWED_CLASS_PATTERNS) {
                 if (allowedClassPattern.matcher(className).matches()) {
                     return true;
                 }
             }
             return false;
         }
 
     }
 
 }