/*
    * 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 org.apache.shiro.crypto.cipher;
  
  import org.apache.shiro.lang.util.ByteSource;
  import org.apache.shiro.lang.util.Destroyable;
  
  import java.io.IOException;
  
  import org.apache.shiro.lang.util.ByteSourceWrapper;
  import org.apache.shiro.lang.util.ByteUtils;
  
  /**
   * A simple implementation that maintains cipher service, ciphertext and key for decrypting it later.
   * {@link #useBytes(ByteSourceUser)} guarantees the sensitive data in byte array will be erased at end of use.
   */
  public class SimpleByteSourceBroker implements ByteSourceBroker, Destroyable {
      private JcaCipherService cipherService;
      private byte[] ciphertext;
      private byte[] key;
      private boolean destroyed;
  
      public SimpleByteSourceBroker(JcaCipherService cipherService, byte[] ciphertext, byte[] key) {
          this.cipherService = cipherService;
          this.ciphertext = ciphertext.clone();
          this.key = key.clone();
      }
  
      public synchronized void useBytes(ByteSourceUser user) {
          if (destroyed || user == null) {
              return;
          }
          ByteSource byteSource = cipherService.decryptInternal(ciphertext, key);
  
          try (ByteSourceWrapper temp = ByteSourceWrapper.wrap(byteSource.getBytes())) {
              user.use(temp.getBytes());
          } catch (IOException e) {
              // ignore
          }
  
      }
  
      public byte[] getClonedBytes() {
          ByteSource byteSource = cipherService.decryptInternal(ciphertext, key);
          // this's a newly created byte array
          return byteSource.getBytes();
      }
  
      public void destroy() throws Exception {
          if (!destroyed) {
              synchronized (this) {
                  destroyed = true;
                  cipherService = null;
                  ByteUtils.wipe(ciphertext);
                  ciphertext = null;
                  ByteUtils.wipe(key);
                  key = null;
              }
          }
      }
  }