/*

 * 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 static java.nio.file.LinkOption.NOFOLLOW_LINKS;

import java.io.File;

import java.io.IOException;

import java.nio.file.AccessDeniedException;

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.

 */

public class PathUtilities {

    /**

     * 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.

     */

    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 createMissingDirectory) 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 (createMissingDirectory) {

                    return Files.createDirectory(result);

                } else {

                    try {

                        return Files.createFile(result);

                    } catch (AccessDeniedException e) {

                        /*

                         * Thrown on Windows if a directory with the same name already exists, so

                         * convert it to FileAlreadyExistsException if that's the case.

                         */

                        throw Files.isDirectory(result, NOFOLLOW_LINKS) ? new FileAlreadyExistsException(e.getFile()) : e;

                    }

                }

            } catch (FileAlreadyExistsException e) {

                uniqueTag = "_" + dumpCounter++;

            }

        }

    }

}