# ReportOutputFolder.java

    /*******************************************************************************
     * Copyright (c) 2009, 2013 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.internal;

    import java.io.IOException;
    import java.io.OutputStream;
    import java.util.HashMap;
    import java.util.Map;

    import org.jacoco.report.IMultiReportOutput;

    /**
     * Logical representation of a folder in the output structure. This utility
     * ensures valid and unique file names and helps to create relative links.
     */
    public class ReportOutputFolder {

    	private final IMultiReportOutput output;

    	private final ReportOutputFolder parent;

    	private final String path;

    	/** Cached sub-folder instances to guarantee stable normalization */
    	private final Map<String, ReportOutputFolder> subFolders = new HashMap<String, ReportOutputFolder>();

    	private final NormalizedFileNames fileNames;

    	/**
    	 * Creates a new root folder for the given output.
    	 *
    	 * @param output
    	 *            output for generated files
    	 */
    	public ReportOutputFolder(final IMultiReportOutput output) {
    		this(output, null, "");
    	}

    	/**
    	 * Creates a new root folder for the given output.
    	 *
    	 * @param output
    	 *            output for generated files
    	 */
    	private ReportOutputFolder(final IMultiReportOutput output,
    			final ReportOutputFolder parent, final String path) {
    		this.output = output;
    		this.parent = parent;
    		this.path = path;
    		fileNames = new NormalizedFileNames();
    	}

    	/**
    	 * Creates a sub-folder with the given name.
    	 *
    	 * @param name
    	 *            name of the sub-folder
    	 * @return handle for output into the sub-folder
    	 */
    	public ReportOutputFolder subFolder(final String name) {
    		final String normalizedName = normalize(name);
    		ReportOutputFolder folder = subFolders.get(normalizedName);
    		if (folder != null) {
    			return folder;
    		}
    		folder = new ReportOutputFolder(output, this, path + normalizedName
    				+ "/");
    		subFolders.put(normalizedName, folder);
    		return folder;
    	}

    	/**
    	 * Creates a new file in this folder with the given local name.
    	 *
    	 * @param name
    	 *            name of the sub-folder
    	 * @return handle for output into the sub-folder
    	 * @throws IOException
    	 *             if the file creation fails
    	 */
    	public OutputStream createFile(final String name) throws IOException {
    		return output.createFile(path + normalize(name));
    	}

    	/**
    	 * Returns a link relative to a given base to a resource within this folder.
    	 *
    	 * @param base
    	 *            base to create the relative link from
    	 * @param name
    	 *            name of the file or folder in this folder
    	 * @return relative link
    	 * @throws IllegalArgumentException
    	 *             if this folder and the base do not have the same root
    	 */
    	public String getLink(final ReportOutputFolder base, final String name) {
    		if (base.isAncestorOf(this)) {
    			return this.path.substring(base.path.length()) + normalize(name);
    		}
    		if (base.parent == null) {
    			throw new IllegalArgumentException("Folders with different roots.");
    		}
    		return "../" + this.getLink(base.parent, name);
    	}

    	private boolean isAncestorOf(final ReportOutputFolder folder) {
    		if (this == folder) {
    			return true;
    		}
    		return folder.parent == null ? false : isAncestorOf(folder.parent);
    	}

    	private String normalize(final String name) {
    		return fileNames.getFileName(name);
    	}

    }