/*
 * 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
 *
 *   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 org.apache.accumulo.server.rpc;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

import org.apache.accumulo.core.conf.AccumuloConfiguration;
import org.apache.accumulo.core.util.ClassUtil;

/**
 * Utility method to ensure that the instance of TCredentials which is passed to the implementation
 * of a Thrift service has the correct principal from SASL at the Thrift transport layer when
 * SASL/GSSAPI (kerberos) is enabled. This ensures that we use the strong authentication provided to
 * us and disallow any other principal names that client (malicious or otherwise) might pass in.
 */
public class TCredentialsUpdatingWrapper {

  public static <T> T service(final T instance, final Class<? extends T> originalClass,
      AccumuloConfiguration conf) {
    InvocationHandler handler = new TCredentialsUpdatingInvocationHandler<>(instance, conf);

    @SuppressWarnings("unchecked")
    T proxiedInstance = (T) Proxy.newProxyInstance(originalClass.getClassLoader(),
        ClassUtil.getInterfaces(instance.getClass()).toArray(new Class<?>[0]), handler);

    return proxiedInstance;
  }

}
