/*
 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package org.graalvm.compiler.debug;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileAlreadyExistsException;
import java.nio.file.Files;
import java.nio.file.InvalidPathException;
import java.nio.file.Path;
import java.nio.file.Paths;

import org.graalvm.compiler.options.OptionKey;
import org.graalvm.compiler.options.OptionValues;

Miscellaneous methods for modifying and generating file system paths.
/**
 * Miscellaneous methods for modifying and generating file system paths.
 */
public class PathUtilities {

    
Gets a value based on name that can be passed to Paths.get(String, String...) without causing an InvalidPathException. 
Returns:
name with all characters invalid for the current file system replaced by '_'/**
     * Gets a value based on {@code name} that can be passed to {@link Paths#get(String, String...)}
     * without causing an {@link InvalidPathException}.
     *
     * @return {@code name} with all characters invalid for the current file system replaced by
     *         {@code '_'}
     */
    public static String sanitizeFileName(String name) {
        try {
            Path path = Paths.get(name);
            if (path.getNameCount() == 0) {
                return name;
            }
        } catch (InvalidPathException e) {
            // fall through
        }
        StringBuilder buf = new StringBuilder(name.length());
        for (int i = 0; i < name.length(); i++) {
            char c = name.charAt(i);
            if (c != File.separatorChar && c != ' ' && !Character.isISOControl(c)) {
                try {
                    Paths.get(String.valueOf(c));
                    buf.append(c);
                    continue;
                } catch (InvalidPathException e) {
                }
            }
            buf.append('_');
        }
        return buf.toString();
    }

    
A maximum file name length supported by most file systems. There is no platform independent
way to get this in Java. Normally it is 255. But for AUFS it is 242. Refer AUFS_MAX_NAMELEN
in http://aufs.sourceforge.net/aufs3/man.html.
/**
     * A maximum file name length supported by most file systems. There is no platform independent
     * way to get this in Java. Normally it is 255. But for AUFS it is 242. Refer AUFS_MAX_NAMELEN
     * in http://aufs.sourceforge.net/aufs3/man.html.
     */
    private static final int MAX_FILE_NAME_LENGTH = 242;

    private static final String ELLIPSIS = "...";

    static Path createUnique(OptionValues options, OptionKey<String> baseNameOption, String id, String label, String ext, boolean createDirectory) throws IOException {
        String uniqueTag = "";
        int dumpCounter = 1;
        String prefix;
        if (id == null) {
            prefix = baseNameOption.getValue(options);
            int slash = prefix.lastIndexOf(File.separatorChar);
            prefix = prefix.substring(slash + 1);
        } else {
            prefix = id;
        }
        for (;;) {
            int fileNameLengthWithoutLabel = uniqueTag.length() + ext.length() + prefix.length() + "[]".length();
            int labelLengthLimit = MAX_FILE_NAME_LENGTH - fileNameLengthWithoutLabel;
            String fileName;
            if (labelLengthLimit < ELLIPSIS.length()) {
                // This means `id` is very long
                String suffix = uniqueTag + ext;
                int idLengthLimit = Math.min(MAX_FILE_NAME_LENGTH - suffix.length(), prefix.length());
                fileName = sanitizeFileName(prefix.substring(0, idLengthLimit) + suffix);
            } else {
                if (label == null) {
                    fileName = sanitizeFileName(prefix + uniqueTag + ext);
                } else {
                    String adjustedLabel = label;
                    if (label.length() > labelLengthLimit) {
                        adjustedLabel = label.substring(0, labelLengthLimit - ELLIPSIS.length()) + ELLIPSIS;
                    }
                    fileName = sanitizeFileName(prefix + '[' + adjustedLabel + ']' + uniqueTag + ext);
                }
            }
            Path dumpDir = DebugOptions.getDumpDirectory(options);
            Path result = Paths.get(dumpDir.toString(), fileName);
            try {
                if (createDirectory) {
                    return Files.createDirectory(result);
                } else {
                    return Files.createFile(result);
                }
            } catch (FileAlreadyExistsException e) {
                uniqueTag = "_" + dumpCounter++;
            }
        }
    }

}