/*

  * Copyright (c) 2013, 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.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * 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 java.lang.invoke;

 import sun.util.logging.PlatformLogger;

 import java.io.FilePermission;

 import java.nio.file.Files;

 import java.nio.file.InvalidPathException;

 import java.nio.file.Path;

 import java.nio.file.Paths;

 import java.security.AccessController;

 import java.security.PrivilegedAction;

 import java.util.Objects;

 import java.util.concurrent.atomic.AtomicBoolean;

 /**

  * Helper class used by InnerClassLambdaMetafactory to log generated classes

  *

  * @implNote

  * <p> Because this class is called by LambdaMetafactory, make use

  * of lambda lead to recursive calls cause stack overflow.

  */

 final class ProxyClassesDumper {

     private static final char[] HEX = {

         '0', '1', '2', '3', '4', '5', '6', '7',

         '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'

     };

     private static final char[] BAD_CHARS = {

         '\\', ':', '*', '?', '"', '<', '>', '|'

     };

     private static final String[] REPLACEMENT = {

         "%5C", "%3A", "%2A", "%3F", "%22", "%3C", "%3E", "%7C"

     };

     private final Path dumpDir;

     public static ProxyClassesDumper getInstance(String path) {

         if (null == path) {

             return null;

         }

         try {

             path = path.trim();

             final Path dir = Paths.get(path.length() == 0 ? "." : path);

             AccessController.doPrivileged(new PrivilegedAction<Void>() {

                     @Override

                     public Void run() {

                         validateDumpDir(dir);

                         return null;

                     }

                 }, null, new FilePermission("<<ALL FILES>>", "read, write"));

             return new ProxyClassesDumper(dir);

         } catch (InvalidPathException ex) {

             PlatformLogger.getLogger(ProxyClassesDumper.class.getName())

                           .warning("Path " + path + " is not valid - dumping disabled", ex);

         } catch (IllegalArgumentException iae) {

             PlatformLogger.getLogger(ProxyClassesDumper.class.getName())

                           .warning(iae.getMessage() + " - dumping disabled");

         }

         return null;

     }

     private ProxyClassesDumper(Path path) {

         dumpDir = Objects.requireNonNull(path);

     }

     private static void validateDumpDir(Path path) {

         if (!Files.exists(path)) {

             throw new IllegalArgumentException("Directory " + path + " does not exist");

         } else if (!Files.isDirectory(path)) {

             throw new IllegalArgumentException("Path " + path + " is not a directory");

         } else if (!Files.isWritable(path)) {

             throw new IllegalArgumentException("Directory " + path + " is not writable");

         }

     }

     public static String encodeForFilename(String className) {

         final int len = className.length();

         StringBuilder sb = new StringBuilder(len);

         for (int i = 0; i < len; i++) {

             char c = className.charAt(i);

             // control characters

             if (c <= 31) {

                 sb.append('%');

                 sb.append(HEX[c >> 4 & 0x0F]);

                 sb.append(HEX[c & 0x0F]);

             } else {

                 int j = 0;

                 for (; j < BAD_CHARS.length; j++) {

                     if (c == BAD_CHARS[j]) {

                         sb.append(REPLACEMENT[j]);

                         break;

                     }

                 }

                 if (j >= BAD_CHARS.length) {

                     sb.append(c);

                 }

             }

         }

         return sb.toString();

     }

     public void dumpClass(String className, final byte[] classBytes) {

         Path file;

         try {

             file = dumpDir.resolve(encodeForFilename(className) + ".class");

         } catch (InvalidPathException ex) {

             PlatformLogger.getLogger(ProxyClassesDumper.class.getName())

                           .warning("Invalid path for class " + className);

             return;

         }

         try {

             Path dir = file.getParent();

             Files.createDirectories(dir);

             Files.write(file, classBytes);

         } catch (Exception ignore) {

             PlatformLogger.getLogger(ProxyClassesDumper.class.getName())

                           .warning("Exception writing to path at " + file.toString());

             // simply don't care if this operation failed

         }

     }

 }