/*
 * Copyright (C) 2017, Google Inc. 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.internal.storage.reftable;

import java.io.IOException;

import org.eclipse.jgit.lib.Ref;

/**
 * Iterator over references inside a
 * {@link org.eclipse.jgit.internal.storage.reftable.Reftable}.
 */
public abstract class RefCursor implements AutoCloseable {
	/**
	 * Check if another reference is available.
	 *
	 * @return {@code true} if there is another result.
	 * @throws java.io.IOException
	 *             references cannot be read.
	 */
	public abstract boolean next() throws IOException;

	/**
	 * Get reference at the current position.
	 *
	 * @return reference at the current position.
	 */
	public abstract Ref getRef();

	/**
	 * Whether the current reference was deleted.
	 *
	 * @return {@code true} if the current reference was deleted.
	 */
	public boolean wasDeleted() {
		Ref r = getRef();
		return r.getStorage() == Ref.Storage.NEW && r.getObjectId() == null;
	}

	/** {@inheritDoc} */
	@Override
	public abstract void close();
}