/*

 * Copyright (c) 1999, 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 sun.misc;

import java.io.File;

import java.io.FilenameFilter;

import java.io.IOException;

import java.io.FileNotFoundException;

import java.util.StringTokenizer;

import java.util.Vector;

import java.util.Enumeration;

import java.util.jar.JarFile;

import java.util.jar.Manifest;

import java.util.jar.Attributes;

import java.util.jar.Attributes.Name;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.security.PrivilegedExceptionAction;

import java.security.PrivilegedActionException;

import java.net.URL;

import java.net.MalformedURLException;

import sun.net.www.ParseUtil;

/**

 * <p>

 * This class checks dependent extensions a particular jar file may have

 * declared through its manifest attributes.

 * </p>

 * Jar file declared dependent extensions through the extension-list

 * attribute. The extension-list contains a list of keys used to

 * fetch the other attributes describing the required extension.

 * If key is the extension key declared in the extension-list

 * attribute, the following describing attribute can be found in

 * the manifest :

 * key-Extension-Name:  (Specification package name)

 * key-Specification-Version: (Specification-Version)

 * key-Implementation-Version: (Implementation-Version)

 * key-Implementation-Vendor-Id: (Imlementation-Vendor-Id)

 * key-Implementation-Version: (Implementation version)

 * key-Implementation-URL: (URL to download the requested extension)

 * <p>

 * This class also maintain versioning consistency of installed

 * extensions dependencies declared in jar file manifest.

 * </p>

 * @author  Jerome Dochez

 */

public class ExtensionDependency {

    /* Callbak interfaces to delegate installation of missing extensions */

    private static Vector<ExtensionInstallationProvider> providers;

    /**

     * <p>

     * Register an ExtensionInstallationProvider. The provider is responsible

     * for handling the installation (upgrade) of any missing extensions.

     * </p>

     * @param eip ExtensionInstallationProvider implementation

     */

    public synchronized static void addExtensionInstallationProvider

        (ExtensionInstallationProvider eip)

    {

        if (providers == null) {

            providers = new Vector<>();

        }

        providers.add(eip);

    }

    /**

     * <p>

     * Unregister a previously installed installation provider

     * </p>

     */

    public synchronized static void removeExtensionInstallationProvider

        (ExtensionInstallationProvider eip)

    {

        providers.remove(eip);

    }

    /**

     * <p>

     * Checks the dependencies of the jar file on installed extension.

     * </p>

     * @param jarFile containing the attriutes declaring the dependencies

     */

    public static boolean checkExtensionsDependencies(JarFile jar)

    {

        if (providers == null) {

            // no need to bother, nobody is registered to install missing

            // extensions

            return true;

        }

        try {

            ExtensionDependency extDep = new ExtensionDependency();

            return extDep.checkExtensions(jar);

        } catch (ExtensionInstallationException e) {

            debug(e.getMessage());

        }

        return false;

    }

    /*

     * Check for all declared required extensions in the jar file

     * manifest.

     */

    protected boolean checkExtensions(JarFile jar)

        throws ExtensionInstallationException

    {

        Manifest man;

        try {

            man = jar.getManifest();

        } catch (IOException e) {

            return false;

        }

        if (man == null) {

            // The applet does not define a manifest file, so

            // we just assume all dependencies are satisfied.

            return true;

        }

        boolean result = true;

        Attributes attr = man.getMainAttributes();

        if (attr != null) {

            // Let's get the list of declared dependencies

            String value = attr.getValue(Name.EXTENSION_LIST);

            if (value != null) {

                StringTokenizer st = new StringTokenizer(value);

                // Iterate over all declared dependencies

                while (st.hasMoreTokens()) {

                    String extensionName = st.nextToken();

                    debug("The file " + jar.getName() +

                          " appears to depend on " + extensionName);

                    // Sanity Check

                    String extName = extensionName + "-" +

                        Name.EXTENSION_NAME.toString();

                    if (attr.getValue(extName) == null) {

                        debug("The jar file " + jar.getName() +

                              " appers to depend on "

                              + extensionName + " but does not define the " +

                              extName + " attribute in its manifest ");

                    } else {

                        if (!checkExtension(extensionName, attr)) {

                            debug("Failed installing " + extensionName);

                            result = false;

                        }

                    }

                }

            } else {

                debug("No dependencies for " + jar.getName());

            }

        }

        return result;

    }

    /*

     * <p>

     * Check that a particular dependency on an extension is satisfied.

     * </p>

     * @param extensionName is the key used for the attributes in the manifest

     * @param attr is the attributes of the manifest file

     *

     * @return true if the dependency is satisfied by the installed extensions

     */

    protected synchronized boolean checkExtension(final String extensionName,

                                     final Attributes attr)

        throws ExtensionInstallationException

    {

        debug("Checking extension " + extensionName);

        if (checkExtensionAgainstInstalled(extensionName, attr))

            return true;

        debug("Extension not currently installed ");

        ExtensionInfo reqInfo = new ExtensionInfo(extensionName, attr);

        return installExtension(reqInfo, null);

    }

    /*

     * <p>

     * Check if a particular extension is part of the currently installed

     * extensions.

     * </p>

     * @param extensionName is the key for the attributes in the manifest

     * @param attr is the attributes of the manifest

     *

     * @return true if the requested extension is already installed

     */

    boolean checkExtensionAgainstInstalled(String extensionName,

                                           Attributes attr)

        throws ExtensionInstallationException

    {

        File fExtension = checkExtensionExists(extensionName);

        if (fExtension != null) {

        // Extension already installed, just check against this one

            try {

                if (checkExtensionAgainst(extensionName, attr, fExtension))

                    return true;

            } catch (FileNotFoundException e) {

                debugException(e);

            } catch (IOException e) {

                debugException(e);

            }

            return false;

        } else {

        // Not sure if extension is already installed, so check all the

        // installed extension jar files to see if we get a match

            File[] installedExts;

            try {

            // Get the list of installed extension jar files so we can

            // compare the installed versus the requested extension

                installedExts = getInstalledExtensions();

            } catch(IOException e) {

                debugException(e);

                return false;

            }

            for (int i=0;i<installedExts.length;i++) {

                try {

                    if (checkExtensionAgainst(extensionName, attr, installedExts[i]))

                        return true;

                } catch (FileNotFoundException e) {

                    debugException(e);

                } catch (IOException e) {

                    debugException(e);

                    // let's continue with the next installed extension

                }

            }

        }

        return false;

    }

    /*

     * <p>

     * Check if the requested extension described by the attributes

     * in the manifest under the key extensionName is compatible with

     * the jar file.

     * </p>

     *

     * @param extensionName key in the attribute list

     * @param attr manifest file attributes

     * @param file installed extension jar file to compare the requested

     * extension against.

     */

    protected boolean checkExtensionAgainst(String extensionName,

                                            Attributes attr,

                                            final File file)

        throws IOException,

               FileNotFoundException,

               ExtensionInstallationException

    {

        debug("Checking extension " + extensionName +

              " against " + file.getName());

        // Load the jar file ...

        Manifest man;

        try {

            man = AccessController.doPrivileged(

                new PrivilegedExceptionAction<Manifest>() {

                    public Manifest run()

                            throws IOException, FileNotFoundException {

                         if (!file.exists())

                             throw new FileNotFoundException(file.getName());

                         JarFile jarFile =  new JarFile(file);

                         return jarFile.getManifest();

                     }

                 });

        } catch(PrivilegedActionException e) {

            if (e.getException() instanceof FileNotFoundException)

                throw (FileNotFoundException) e.getException();

            throw (IOException) e.getException();

        }

        // Construct the extension information object

        ExtensionInfo reqInfo = new ExtensionInfo(extensionName, attr);

        debug("Requested Extension : " + reqInfo);

        int isCompatible = ExtensionInfo.INCOMPATIBLE;

        ExtensionInfo instInfo = null;

        if (man != null) {

            Attributes instAttr = man.getMainAttributes();

            if (instAttr != null) {

                instInfo = new ExtensionInfo(null, instAttr);

                debug("Extension Installed " + instInfo);

                isCompatible = instInfo.isCompatibleWith(reqInfo);

                switch(isCompatible) {

                case ExtensionInfo.COMPATIBLE:

                    debug("Extensions are compatible");

                    return true;

                case ExtensionInfo.INCOMPATIBLE:

                    debug("Extensions are incompatible");

                    return false;

                default:

                    // everything else

                    debug("Extensions require an upgrade or vendor switch");

                    return installExtension(reqInfo, instInfo);

                }

            }

        }

        return false;

    }

    /*

     * <p>

     * An required extension is missing, if an ExtensionInstallationProvider is

     * registered, delegate the installation of that particular extension to it.

     * </p>

     *

     * @param reqInfo Missing extension information

     * @param instInfo Older installed version information

     *

     * @return true if the installation is successful

     */

    protected boolean installExtension(ExtensionInfo reqInfo,

                                       ExtensionInfo instInfo)

        throws ExtensionInstallationException

    {

        Vector<ExtensionInstallationProvider> currentProviders;

        synchronized(providers) {

            @SuppressWarnings("unchecked")

            Vector<ExtensionInstallationProvider> tmp =

                (Vector<ExtensionInstallationProvider>) providers.clone();

            currentProviders = tmp;

        }

        for (Enumeration<ExtensionInstallationProvider> e = currentProviders.elements();

                e.hasMoreElements();) {

            ExtensionInstallationProvider eip = e.nextElement();

            if (eip!=null) {

                // delegate the installation to the provider

                if (eip.installExtension(reqInfo, instInfo)) {

                    debug(reqInfo.name + " installation successful");

                    Launcher.ExtClassLoader cl = (Launcher.ExtClassLoader)

                        Launcher.getLauncher().getClassLoader().getParent();

                    addNewExtensionsToClassLoader(cl);

                    return true;

                }

            }

        }

        // We have tried all of our providers, noone could install this

        // extension, we just return failure at this point

        debug(reqInfo.name + " installation failed");

        return false;

    }

    /**

     * <p>

     * Checks if the extension, that is specified in the extension-list in

     * the applet jar manifest, is already installed (i.e. exists in the

     * extension directory).

     * </p>

     *

     * @param extensionName extension name in the extension-list

     *

     * @return the extension if it exists in the extension directory

     */

    private File checkExtensionExists(String extensionName) {

        // Function added to fix bug 4504166

        final String extName = extensionName;

        final String[] fileExt = {".jar", ".zip"};

        return AccessController.doPrivileged(

            new PrivilegedAction<File>() {

                public File run() {

                    try {

                        File fExtension;

                        File[] dirs = getExtDirs();

                        // Search the extension directories for the extension that is specified

                        // in the attribute extension-list in the applet jar manifest

                        for (int i=0;i<dirs.length;i++) {

                            for (int j=0;j<fileExt.length;j++) {

                                if (extName.toLowerCase().endsWith(fileExt[j])) {

                                    fExtension = new File(dirs[i], extName);

                                } else {

                                    fExtension = new File(dirs[i], extName+fileExt[j]);

                                }

                                debug("checkExtensionExists:fileName " + fExtension.getName());

                                if (fExtension.exists()) {

                                    return fExtension;

                                }

                            }

                        }

                        return null;

                    } catch(Exception e) {

                         debugException(e);

                         return null;

                    }

                }

            });

    }

    /**

     * <p>

     * @return the java.ext.dirs property as a list of directory

     * </p>

     */

    private static File[] getExtDirs() {

        String s = java.security.AccessController.doPrivileged(

                new sun.security.action.GetPropertyAction("java.ext.dirs"));

        File[] dirs;

        if (s != null) {

            StringTokenizer st =

                new StringTokenizer(s, File.pathSeparator);

            int count = st.countTokens();

            debug("getExtDirs count " + count);

            dirs = new File[count];

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

                dirs[i] = new File(st.nextToken());

                debug("getExtDirs dirs["+i+"] "+ dirs[i]);

            }

        } else {

            dirs = new File[0];

            debug("getExtDirs dirs " + dirs);

        }

        debug("getExtDirs dirs.length " + dirs.length);

        return dirs;

    }

    /*

     * <p>

     * Scan the directories and return all files installed in those

     * </p>

     * @param dirs list of directories to scan

     *

     * @return the list of files installed in all the directories

     */

    private static File[] getExtFiles(File[] dirs) throws IOException {

        Vector<File> urls = new Vector<File>();

        for (int i = 0; i < dirs.length; i++) {

            String[] files = dirs[i].list(new JarFilter());

            if (files != null) {

                debug("getExtFiles files.length " + files.length);

                for (int j = 0; j < files.length; j++) {

                    File f = new File(dirs[i], files[j]);

                    urls.add(f);

                    debug("getExtFiles f["+j+"] "+ f);

                }

            }

        }

        File[] ua = new File[urls.size()];

        urls.copyInto(ua);

        debug("getExtFiles ua.length " + ua.length);

        return ua;

    }

    /*

     * <p>

     * @return the list of installed extensions jar files

     * </p>

     */

    private File[] getInstalledExtensions() throws IOException {

        return AccessController.doPrivileged(

            new PrivilegedAction<File[]>() {

                public File[] run() {

                     try {

                         return getExtFiles(getExtDirs());

                     } catch(IOException e) {

                         debug("Cannot get list of installed extensions");

                         debugException(e);

                        return new File[0];

                     }

                 }

            });

    }

    /*

     * <p>

     * Add the newly installed jar file to the extension class loader.

     * </p>

     *

     * @param cl the current installed extension class loader

     *

     * @return true if successful

     */

    private Boolean addNewExtensionsToClassLoader(Launcher.ExtClassLoader cl) {

        try {

            File[] installedExts = getInstalledExtensions();

            for (int i=0;i<installedExts.length;i++) {

                final File instFile = installedExts[i];

                URL instURL = AccessController.doPrivileged(

                    new PrivilegedAction<URL>() {

                        public URL run() {

                            try {

                                return ParseUtil.fileToEncodedURL(instFile);

                            } catch (MalformedURLException e) {

                                debugException(e);

                                return null;

                            }