/*
    * Copyright 2018 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.handler.ssl;
  
  import io.netty.util.internal.ObjectUtil;
  
  import javax.net.ssl.KeyManager;
  import javax.net.ssl.KeyManagerFactory;
  import javax.net.ssl.KeyManagerFactorySpi;
  import javax.net.ssl.ManagerFactoryParameters;
  import javax.net.ssl.X509KeyManager;
  import java.security.InvalidAlgorithmParameterException;
  import java.security.KeyStore;
  import java.security.KeyStoreException;
  import java.security.NoSuchAlgorithmException;
  import java.security.PrivateKey;
  import java.security.UnrecoverableKeyException;
  import java.security.cert.X509Certificate;
  
  /**
   * Wraps another {@link KeyManagerFactory} and caches its chains / certs for an alias for better performance when using
   * {@link SslProvider#OPENSSL} or {@link SslProvider#OPENSSL_REFCNT}.
   *
   * Because of the caching its important that the wrapped {@link KeyManagerFactory}s {@link X509KeyManager}s always
   * return the same {@link X509Certificate} chain and {@link PrivateKey} for the same alias.
   */
  public final class OpenSslCachingX509KeyManagerFactory extends KeyManagerFactory {
  
      private final int maxCachedEntries;
  
      public OpenSslCachingX509KeyManagerFactory(final KeyManagerFactory factory) {
          this(factory, 1024);
      }
  
      public OpenSslCachingX509KeyManagerFactory(final KeyManagerFactory factory, int maxCachedEntries) {
          super(new KeyManagerFactorySpi() {
              @Override
              protected void engineInit(KeyStore keyStore, char[] chars)
                      throws KeyStoreException, NoSuchAlgorithmException, UnrecoverableKeyException {
                  factory.init(keyStore, chars);
              }
  
              @Override
              protected void engineInit(ManagerFactoryParameters managerFactoryParameters)
                      throws InvalidAlgorithmParameterException {
                  factory.init(managerFactoryParameters);
              }
  
              @Override
              protected KeyManager[] engineGetKeyManagers() {
                  return factory.getKeyManagers();
              }
          }, factory.getProvider(), factory.getAlgorithm());
          this.maxCachedEntries = ObjectUtil.checkPositive(maxCachedEntries, "maxCachedEntries");
      }
  
      OpenSslKeyMaterialProvider newProvider(String password) {
          X509KeyManager keyManager = ReferenceCountedOpenSslContext.chooseX509KeyManager(getKeyManagers());
          if ("sun.security.ssl.X509KeyManagerImpl".equals(keyManager.getClass().getName())) {
              // Don't do caching if X509KeyManagerImpl is used as the returned aliases are not stable and will change
              // between invocations.
              return new OpenSslKeyMaterialProvider(keyManager, password);
          }
          return new OpenSslCachingKeyMaterialProvider(
                  ReferenceCountedOpenSslContext.chooseX509KeyManager(getKeyManagers()), password, maxCachedEntries);
      }
  }