/*
 * Copyright (C) 2016, Google Inc.
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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 */
package org.eclipse.jgit.http.test;

import java.io.IOException;

import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
import org.eclipse.jgit.lib.RefDatabase;

/**
 * An {@link InMemoryRepository} whose refs can be made unreadable for testing
 * purposes.
 */
class RefsUnreadableInMemoryRepository extends InMemoryRepository {

	private final RefsUnreadableRefDatabase refs;

	private volatile boolean failing;

	RefsUnreadableInMemoryRepository(DfsRepositoryDescription repoDesc) {
		super(repoDesc);
		refs = new RefsUnreadableRefDatabase();
		failing = false;
	}

	@Override
	public RefDatabase getRefDatabase() {
		return refs;
	}

	/**
	 * Make the ref database unable to scan its refs.
	 * <p>
	 * It may be useful to follow a call to startFailing with a call to
	 * {@link RefDatabase#refresh()}, ensuring the next ref read fails.
	 */
	void startFailing() {
		failing = true;
	}

	private class RefsUnreadableRefDatabase extends MemRefDatabase {

		@Override
		protected RefCache scanAllRefs() throws IOException {
			if (failing) {
				throw new IOException("disk failed, no refs found");
			} else {
				return super.scanAllRefs();
			}
		}
	}
}