/*******************************************************************************
 * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Marc R. Hoffmann - initial API and implementation
 *    
 *******************************************************************************/
package org.jacoco.report;

import java.io.IOException;
import java.io.Reader;

/**
 * Interface to look-up source files that will be included with the report.
 */
public interface ISourceFileLocator {

	/**
	 * Tries to locate the given source file and opens a reader with the
	 * appropriate encoding.
	 * 
	 * @param packageName
	 *            VM name of the package
	 * @param fileName
	 *            name of the source file
	 * @return reader if the file could be located, <code>null</code> otherwise
	 * @throws IOException
	 *             in case of problems while opening the file
	 */
	public Reader getSourceFile(String packageName, String fileName)
			throws IOException;

	/**
	 * Returns number of blank characters that represent a tab in source code.
	 * 
	 * @return tab width as number of blanks
	 */
	public int getTabWidth();

}
