/*
    * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  package org.eclipse.jgit.transport.sshd;
  
  import java.nio.file.Path;
  import java.security.KeyPair;
  import java.security.PrivateKey;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.function.Function;
  
  import javax.security.auth.DestroyFailedException;
  
  /**
   * A simple {@link KeyCache}. JGit uses one such cache in its
   * {@link SshdSessionFactory} to avoid loading keys multiple times.
   *
   * @since 5.2
   */
  public class JGitKeyCache implements KeyCache {
  
  	private AtomicReference<Map<Path, KeyPair>> cache = new AtomicReference<>(
  			new ConcurrentHashMap<>());
  
  	@Override
  	public KeyPair get(Path path,
  			Function<? super Path, ? extends KeyPair> loader) {
  		return cache.get().computeIfAbsent(path, loader);
  	}
  
  	@Override
  	public void close() {
  		Map<Path, KeyPair> map = cache.getAndSet(null);
  		if (map == null) {
  			return;
  		}
  		for (KeyPair k : map.values()) {
  			PrivateKey p = k.getPrivate();
  			try {
  				p.destroy();
  			} catch (DestroyFailedException e) {
  				// Ignore here. We did our best.
  			}
  		}
  		map.clear();
  	}
  }