/*

 * 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.

 */

import java.io.ByteArrayInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.FileNotFoundException;

import java.io.InputStream;

import java.io.ByteArrayInputStream;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.nio.file.StandardCopyOption;

import java.util.zip.ZipEntry;

import java.util.zip.ZipOutputStream;

/**

 * Dump a class file for a class on the class path in the current directory, or

 * in the specified JAR file. This class is usually used when you build a class

 * from a test library, but want to use this class in a sub-process.

 *

 * For example, to build the following library class:

 * test/lib/sun/hotspot/WhiteBox.java

 *

 * You would use the following tags:

 *

 * @library /test/lib

 * @build sun.hotspot.WhiteBox

 *

 * JTREG would build the class file under

 * ${JTWork}/classes/test/lib/sun/hotspot/WhiteBox.class

 *

 * With you run your main test class using "@run main MyMainClass", JTREG would setup the

 * -classpath to include "${JTWork}/classes/test/lib/", so MyMainClass would be able to

 * load the WhiteBox class.

 *

 * However, if you run a sub process, and do not wish to use the exact same -classpath,

 * You can use ClassFileInstaller to ensure that WhiteBox is available in the current

 * directory of your test:

 *

 * @run main ClassFileInstaller sun.hotspot.WhiteBox

 *

 * Or, you can use the -jar option to store the class in the specified JAR file. If a relative

 * path name is given, the JAR file would be relative to the current directory of

 *

 * @run main ClassFileInstaller -jar myjar.jar sun.hotspot.WhiteBox

 */

public class ClassFileInstaller {

    /**

     * You can enable debug tracing of ClassFileInstaller by running JTREG with

     * jtreg -DClassFileInstaller.debug=true ... <names of tests>

     */

    public static boolean DEBUG = Boolean.getBoolean("ClassFileInstaller.debug");

    /**

     * @param args The names of the classes to dump

     * @throws Exception

     */

    public static void main(String... args) throws Exception {

        if (args.length > 1 && args[0].equals("-jar")) {

            if (args.length < 2) {

                throw new RuntimeException("Usage: ClassFileInstaller <options> <classes>\n" +

                                           "where possible options include:\n" +

                                           "  -jar <path>             Write to the JAR file <path>");

            }

            writeJar(args[1], null, args, 2, args.length);

        } else {

            if (DEBUG) {

                System.out.println("ClassFileInstaller: Writing to " + System.getProperty("user.dir"));

            }

            for (String arg : args) {

                writeClassToDisk(arg);

            }

        }

    }

    public static class Manifest {

        private InputStream in;

        private Manifest(InputStream in) {

            this.in = in;

        }

        static Manifest fromSourceFile(String fileName) throws Exception {

            String pathName = System.getProperty("test.src") + File.separator + fileName;

            return new Manifest(new FileInputStream(pathName));

        }

        // Example:

        //  String manifest = "Premain-Class: RedefineClassHelper\n" +

        //                "Can-Redefine-Classes: true\n";

        //  ClassFileInstaller.writeJar("redefineagent.jar",

        //    ClassFileInstaller.Manifest.fromString(manifest),

        //    "RedefineClassHelper");

        static Manifest fromString(String manifest) throws Exception {

            return new Manifest(new ByteArrayInputStream(manifest.getBytes()));

        }

        public InputStream getInputStream() {

            return in;

        }

    }

    private static void writeJar(String jarFile, Manifest manifest, String classes[], int from, int to) throws Exception {

        if (DEBUG) {

            System.out.println("ClassFileInstaller: Writing to " + getJarPath(jarFile));

        }

        (new File(jarFile)).delete();

        FileOutputStream fos = new FileOutputStream(jarFile);

        ZipOutputStream zos = new ZipOutputStream(fos);

        // The manifest must be the first or second entry. See comments in JarInputStream

        // constructor and JDK-5046178.

        if (manifest != null) {

            writeToDisk(zos, "META-INF/MANIFEST.MF", manifest.getInputStream());

        }

        for (int i=from; i<to; i++) {

            writeClassToDisk(zos, classes[i]);

        }

        zos.close();

        fos.close();

    }

    /*

     * You can call ClassFileInstaller.writeJar() from your main test class instead of

     * using "@run ClassFileInstaller -jar ...". E.g.,

     *

     * String jarPath = ClassFileInstaller.getJarPath("myjar.jar", "sun.hotspot.WhiteBox")

     *

     * If you call this API, make sure you build ClassFileInstaller with the following tags:

     *

     * @library testlibrary

     * @build ClassFileInstaller

     */

    public static String writeJar(String jarFile, String... classes) throws Exception {

        writeJar(jarFile, null, classes, 0, classes.length);

        return getJarPath(jarFile);

    }

    public static String writeJar(String jarFile, Manifest manifest, String... classes) throws Exception {

        writeJar(jarFile, manifest, classes, 0, classes.length);

        return getJarPath(jarFile);

    }

    /**

     * This returns the absolute path to the file specified in "@ClassFileInstaller -jar myjar.jar",

     * In your test program, instead of using the JAR file name directly:

     *

     * String jarPath = "myjar.jar";

     *

     * you should call this function, like:

     *

     * String jarPath = ClassFileInstaller.getJarPath("myjar.jar")

     *

     * The reasons are:

     * (1) Using absolute path makes it easy to cut-and-paste from the JTR file and rerun your

     *     test in any directory.

     * (2) In the future, we may make the JAR file name unique to avoid clobbering

     *     during parallel JTREG execution.

     *

     */

    public static String getJarPath(String jarFileName) {

        return new File(jarFileName).getAbsolutePath();

    }

    public static void writeClassToDisk(String className) throws Exception {

        writeClassToDisk((ZipOutputStream)null, className);

    }

    private static void writeClassToDisk(ZipOutputStream zos, String className) throws Exception {

        writeClassToDisk(zos, className, "");

    }

    public static void writeClassToDisk(String className, String prependPath) throws Exception {

        writeClassToDisk(null, className, prependPath);

    }

    private static void writeClassToDisk(ZipOutputStream zos, String className, String prependPath) throws Exception {

        ClassLoader cl = ClassFileInstaller.class.getClassLoader();

        // Convert dotted class name to a path to a class file

        String pathName = className.replace('.', '/').concat(".class");

        InputStream is = cl.getResourceAsStream(pathName);

        if (is == null) {

            throw new RuntimeException("Failed to find " + pathName);

        }

        if (prependPath.length() > 0) {

            pathName = prependPath + "/" + pathName;

        }

        writeToDisk(zos, pathName, is);

    }

    public static void writeClassToDisk(String className, byte[] bytecode) throws Exception {

        writeClassToDisk(null, className, bytecode);

    }

    private static void writeClassToDisk(ZipOutputStream zos, String className, byte[] bytecode) throws Exception {

        writeClassToDisk(zos, className, bytecode, "");

    }

    public static void writeClassToDisk(String className, byte[] bytecode, String prependPath) throws Exception {

        writeClassToDisk(null, className, bytecode, prependPath);

    }

    private static void writeClassToDisk(ZipOutputStream zos, String className, byte[] bytecode, String prependPath) throws Exception {

        // Convert dotted class name to a path to a class file

        String pathName = className.replace('.', '/').concat(".class");

        if (prependPath.length() > 0) {

            pathName = prependPath + "/" + pathName;

        }

        writeToDisk(zos, pathName, new ByteArrayInputStream(bytecode));

    }

    private static void writeToDisk(ZipOutputStream zos, String pathName, InputStream is) throws Exception {

        if (DEBUG) {

            System.out.println("ClassFileInstaller: Writing " + pathName);

        }

        if (zos != null) {

            ZipEntry ze = new ZipEntry(pathName);

            zos.putNextEntry(ze);

            byte[] buf = new byte[1024];

            int len;

            while ((len = is.read(buf))>0){

                zos.write(buf, 0, len);

            }

        } else {

            // Create the class file's package directory

            Path p = Paths.get(pathName);

            if (pathName.contains("/")) {

                Files.createDirectories(p.getParent());

            }

            // Create the class file

            Files.copy(is, p, StandardCopyOption.REPLACE_EXISTING);

        }

        is.close();

    }

}