/* PluginAppletSecurityContext -- execute plugin JNI messages
   Copyright (C) 2008, 2010  Red Hat

This file is part of IcedTea.

IcedTea is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

IcedTea 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 for more details.

You should have received a copy of the GNU General Public License
along with IcedTea; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package sun.applet;

import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.AccessControlContext;
import java.security.AccessControlException;
import java.security.AccessController;
import java.security.AllPermission;
import java.security.BasicPermission;
import java.security.CodeSource;
import java.security.Permissions;
import java.security.PrivilegedAction;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;

import net.sourceforge.jnlp.runtime.JNLPRuntime;
import net.sourceforge.jnlp.DefaultLaunchHandler;
import netscape.javascript.JSObjectCreatePermission;

class Signature {
    private String signature;
    private int currentIndex;
    private List<Class> typeList;
    private static final char ARRAY = '[';
    private static final char OBJECT = 'L';
    private static final char SIGNATURE_ENDCLASS = ';';
    private static final char SIGNATURE_FUNC = '(';
    private static final char SIGNATURE_ENDFUNC = ')';
    private static final char VOID = 'V';
    private static final char BOOLEAN = 'Z';
    private static final char BYTE = 'B';
    private static final char CHARACTER = 'C';
    private static final char SHORT = 'S';
    private static final char INTEGER = 'I';
    private static final char LONG = 'J';
    private static final char FLOAT = 'F';
    private static final char DOUBLE = 'D';

    private String nextTypeName() {
        char key = signature.charAt(currentIndex++);

        switch (key) {
            case ARRAY:
                return nextTypeName() + "[]";

            case OBJECT:
                int endClass = signature.indexOf(SIGNATURE_ENDCLASS, currentIndex);
                String retVal = signature.substring(currentIndex, endClass);
                retVal = retVal.replace('/', '.');
                currentIndex = endClass + 1;
                return retVal;

                // FIXME: generated bytecode with classes named after
                // primitives will not work in this scheme -- those
                // classes will be incorrectly treated as primitive
                // types.
            case VOID:
                return "void";
            case BOOLEAN:
                return "boolean";
            case BYTE:
                return "byte";
            case CHARACTER:
                return "char";
            case SHORT:
                return "short";
            case INTEGER:
                return "int";
            case LONG:
                return "long";
            case FLOAT:
                return "float";
            case DOUBLE:
                return "double";

            case SIGNATURE_ENDFUNC:
                return null;

            case SIGNATURE_FUNC:
                return nextTypeName();

            default:
                throw new IllegalArgumentException(
                                        "Invalid JNI signature character '" + key + "'");
        }
    }

    public Signature(String signature, ClassLoader cl) {
        this.signature = signature;
        currentIndex = 0;
        typeList = new ArrayList<Class>(10);

        String elem;
        while (currentIndex < signature.length()) {
            elem = nextTypeName();

            if (elem == null) // end of signature
                continue;

            Class primitive = primitiveNameToType(elem);
            if (primitive != null)
                typeList.add(primitive);
            else {
                int dimsize = 0;
                int n = elem.indexOf('[');
                if (n != -1) {
                    String arrayType = elem.substring(0, n);
                    dimsize++;
                    n = elem.indexOf('[', n + 1);
                    while (n != -1) {
                        dimsize++;
                        n = elem.indexOf('[', n + 1);
                    }
                    int[] dims = new int[dimsize];
                    primitive = primitiveNameToType(arrayType);
                    if (primitive != null) {
                        typeList.add(Array.newInstance(primitive, dims)
                                                                .getClass());
                    } else
                        typeList.add(Array.newInstance(
                                                                getClass(arrayType, cl), dims).getClass());
                } else {
                    typeList.add(getClass(elem, cl));
                }
            }
        }
        if (signature.length() < 2) {
            throw new IllegalArgumentException("Invalid JNI signature '"
                                        + signature + "'");
        }
    }

    public static Class getClass(String name, ClassLoader cl) {

        Class c = null;

        try {
            c = Class.forName(name);
        } catch (ClassNotFoundException cnfe) {

            PluginDebug.debug("Class ", name, " not found in primordial loader. Looking in ", cl);
            try {
                c = cl.loadClass(name);
            } catch (ClassNotFoundException e) {
                throw (new RuntimeException(new ClassNotFoundException("Unable to find class " + name)));
            }
        }

        return c;
    }

    public static Class primitiveNameToType(String name) {
        if (name.equals("void"))
            return Void.TYPE;
        else if (name.equals("boolean"))
            return Boolean.TYPE;
        else if (name.equals("byte"))
            return Byte.TYPE;
        else if (name.equals("char"))
            return Character.TYPE;
        else if (name.equals("short"))
            return Short.TYPE;
        else if (name.equals("int"))
            return Integer.TYPE;
        else if (name.equals("long"))
            return Long.TYPE;
        else if (name.equals("float"))
            return Float.TYPE;
        else if (name.equals("double"))
            return Double.TYPE;
        else
            return null;
    }

    public Class[] getClassArray() {
        return typeList.subList(0, typeList.size()).toArray(new Class[] {});
    }
}

public class PluginAppletSecurityContext {

    private static Hashtable<ClassLoader, URL> classLoaders = new Hashtable<ClassLoader, URL>();
    private static Hashtable<Integer, ClassLoader> instanceClassLoaders = new Hashtable<Integer, ClassLoader>();

    private PluginObjectStore store = PluginObjectStore.getInstance();
    private Throwable throwable = null;
    private ClassLoader liveconnectLoader = ClassLoader.getSystemClassLoader();
    int identifier = 0;

    public static PluginStreamHandler streamhandler;

    long startTime = 0;

    public PluginAppletSecurityContext(int identifier) {
        this.identifier = identifier;

        // We need a security manager.. and since there is a good chance that
        // an applet will be loaded at some point, we should make it the SM
        // that JNLPRuntime will try to install
        if (System.getSecurityManager() == null) {
            JNLPRuntime.initialize(/* isApplication */false);
            JNLPRuntime.setDefaultLaunchHandler(new DefaultLaunchHandler(System.err));
        }

        JNLPRuntime.disableExit();

        URL u = null;
        try {
            u = new URL("file://");
        } catch (Exception e) {
            e.printStackTrace();
        }

        this.classLoaders.put(liveconnectLoader, u);
    }

    private static <V> V parseCall(String s, ClassLoader cl, Class<V> c) {
        if (c == Integer.class)
            return c.cast(new Integer(s));
        else if (c == String.class)
            return c.cast(new String(s));
        else if (c == Signature.class)
            return c.cast(new Signature(s, cl));
        else
            throw new RuntimeException("Unexpected call value.");
    }

    private Object parseArgs(String s, Class c) {
        if (c == Boolean.TYPE || c == Boolean.class)
            return new Boolean(s);
        else if (c == Byte.TYPE || c == Byte.class)
            return new Byte(s);
        else if (c == Character.TYPE || c == Character.class) {
            String[] bytes = s.split("_");
            int low = Integer.parseInt(bytes[0]);
            int high = Integer.parseInt(bytes[1]);
            int full = ((high << 8) & 0x0ff00) | (low & 0x0ff);
            return new Character((char) full);
        } else if (c == Short.TYPE || c == Short.class)
            return new Short(s);
        else if (c == Integer.TYPE || c == Integer.class)
            return new Integer(s);
        else if (c == Long.TYPE || c == Long.class)
            return new Long(s);
        else if (c == Float.TYPE || c == Float.class)
            return new Float(s);
        else if (c == Double.TYPE || c == Double.class)
            return new Double(s);
        else
            return store.getObject(new Integer(s));
    }

    public void associateSrc(ClassLoader cl, URL src) {
        PluginDebug.debug("Associating ", cl, " with ", src);
        this.classLoaders.put(cl, src);
    }

    public void associateInstance(Integer i, ClassLoader cl) {
        PluginDebug.debug("Associating ", cl, " with instance ", i);
        this.instanceClassLoaders.put(i, cl);
    }

    public static void setStreamhandler(PluginStreamHandler sh) {
        streamhandler = sh;
    }

    public static Map<String, String> getLoaderInfo() {
        Hashtable<String, String> map = new Hashtable<String, String>();

        for (ClassLoader loader : PluginAppletSecurityContext.classLoaders.keySet()) {
            map.put(loader.getClass().getName(), classLoaders.get(loader).toString());
        }

        return map;
    }

    public void handleMessage(int reference, String src, AccessControlContext callContext, String message) {

        startTime = new java.util.Date().getTime();

        try {
            if (message.startsWith("FindClass")) {
                ClassLoader cl = null;
                Class c = null;
                cl = liveconnectLoader;
                String[] args = message.split(" ");
                Integer instance = new Integer(args[1]);
                String className = args[2].replace('/', '.');
                PluginDebug.debug("Searching for class ", className, " in ", cl);

                try {
                    c = cl.loadClass(className);
                    store.reference(c);
                    write(reference, "FindClass " + store.getIdentifier(c));
                } catch (ClassNotFoundException cnfe) {

                    cl = this.instanceClassLoaders.get(instance);
                    PluginDebug.debug("Not found. Looking in ", cl);

                    if (instance != 0 && cl != null) {
                        try {
                            c = cl.loadClass(className);
                            store.reference(c);
                            write(reference, "FindClass " + store.getIdentifier(c));
                        } catch (ClassNotFoundException cnfe2) {
                            write(reference, "FindClass 0");
                        }
                    } else {
                        write(reference, "FindClass 0");
                    }
                }

            } else if (message.startsWith("GetStaticMethodID")
                                        || message.startsWith("GetMethodID")) {
                String[] args = message.split(" ");
                Integer classID = parseCall(args[1], null, Integer.class);
                String methodName = parseCall(args[2], null, String.class);
                Signature signature = parseCall(args[3], ((Class) store.getObject(classID)).getClassLoader(), Signature.class);
                Object[] a = signature.getClassArray();

                Class<?> c;

                if (message.startsWith("GetStaticMethodID") ||
                                    methodName.equals("<init>") ||
                                    methodName.equals("<clinit>"))
                    c = (Class<?>) store.getObject(classID);
                else
                    c = store.getObject(classID).getClass();

                Method m = null;
                Constructor cs = null;
                Object o = null;
                if (methodName.equals("<init>")
                                                || methodName.equals("<clinit>")) {
                    o = cs = c.getConstructor(signature.getClassArray());
                    store.reference(cs);
                } else {
                    o = m = c.getMethod(methodName, signature.getClassArray());
                    store.reference(m);
                }
                PluginDebug.debug(o, " has id ", store.getIdentifier(o));
                write(reference, args[0] + " " + store.getIdentifier(o));
            } else if (message.startsWith("GetStaticFieldID")
                                        || message.startsWith("GetFieldID")) {
                String[] args = message.split(" ");
                Integer classID = parseCall(args[1], null, Integer.class);
                Integer fieldID = parseCall(args[2], null, Integer.class);
                String fieldName = (String) store.getObject(fieldID);

                Class<?> c = (Class<?>) store.getObject(classID);

                PluginDebug.debug("GetStaticFieldID/GetFieldID got class=", c.getName());

                Field f = null;
                f = c.getField(fieldName);

                store.reference(f);

                write(reference, "GetStaticFieldID " + store.getIdentifier(f));
            } else if (message.startsWith("GetStaticField")) {
                String[] args = message.split(" ");
                String type = parseCall(args[1], null, String.class);
                Integer classID = parseCall(args[1], null, Integer.class);
                Integer fieldID = parseCall(args[2], null, Integer.class);

                final Class<?> c = (Class<?>) store.getObject(classID);
                final Field f = (Field) store.getObject(fieldID);

                AccessControlContext acc = callContext != null ? callContext : getClosedAccessControlContext();
                checkPermission(src, c, acc);

                Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
                    public Object run() {
                        try {
                            return f.get(c);
                        } catch (Throwable t) {
                            return t;
                        }
                    }
                }, acc);

                if (ret instanceof Throwable)
                    throw (Throwable) ret;

                if (ret == null) {
                    write(reference, "GetStaticField literalreturn null");
                } else if (f.getType() == Boolean.TYPE
                        || f.getType() == Byte.TYPE
                        || f.getType() == Short.TYPE
                        || f.getType() == Integer.TYPE
                        || f.getType() == Long.TYPE) {
                    write(reference, "GetStaticField literalreturn " + ret);
                } else if (f.getType() == Float.TYPE
                                || f.getType() == Double.TYPE) {
                    write(reference, "GetStaticField literalreturn " + String.format("%308.308e", ret));
                } else if (f.getType() == Character.TYPE) {
                    write(reference, "GetStaticField literalreturn " + (int) (Character) ret);
                } else {
                    // Track returned object.
                    store.reference(ret);
                    write(reference, "GetStaticField " + store.getIdentifier(ret));
                }
            } else if (message.startsWith("GetValue")) {
                String[] args = message.split(" ");
                Integer index = parseCall(args[1], null, Integer.class);

                Object ret = store.getObject(index);

                if (ret == null) {
                    write(reference, "GetValue literalreturn null");
                } else if (ret.getClass() == Boolean.TYPE
                        || ret.getClass() == Boolean.class
                        || ret.getClass() == Byte.TYPE
                        || ret.getClass() == Byte.class
                        || ret.getClass() == Short.TYPE
                        || ret.getClass() == Short.class
                        || ret.getClass() == Integer.TYPE
                        || ret.getClass() == Integer.class
                        || ret.getClass() == Long.TYPE
                        || ret.getClass() == Long.class) {
                    write(reference, "GetValue literalreturn " + ret);
                } else if (ret.getClass() == Float.TYPE
                        || ret.getClass() == Float.class
                        || ret.getClass() == Double.TYPE
                        || ret.getClass() == Double.class) {
                    write(reference, "GetValue literalreturn " + String.format("%308.308e", ret));
                } else if (ret.getClass() == Character.TYPE
                        || ret.getClass() == Character.class) {
                    write(reference, "GetValue literalreturn " + (int) (Character) ret);
                } else {
                    // Track returned object.
                    store.reference(ret);
                    write(reference, "GetValue " + store.getIdentifier(ret));
                }
            } else if (message.startsWith("SetStaticField") ||
                                   message.startsWith("SetField")) {
                String[] args = message.split(" ");
                Integer classOrObjectID = parseCall(args[1], null, Integer.class);
                Integer fieldID = parseCall(args[2], null, Integer.class);
                Object value = store.getObject(parseCall(args[3], null, Integer.class));

                final Object o = store.getObject(classOrObjectID);
                final Field f = (Field) store.getObject(fieldID);

                final Object fValue = MethodOverloadResolver.getCostAndCastedObject(value, f.getType())[1];

                AccessControlContext acc = callContext != null ? callContext : getClosedAccessControlContext();
                checkPermission(src,
                                                message.startsWith("SetStaticField") ? (Class) o : o.getClass(),
                                                acc);

                Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
                    public Object run() {
                        try {
                            f.set(o, fValue);
                        } catch (Throwable t) {
                            return t;
                        }

                        return null;
                    }
                }, acc);

                if (ret instanceof Throwable)
                    throw (Throwable) ret;

                write(reference, "SetField");
            } else if (message.startsWith("GetObjectArrayElement")) {
                String[] args = message.split(" ");
                Integer arrayID = parseCall(args[1], null, Integer.class);
                Integer index = parseCall(args[2], null, Integer.class);

                Object ret = Array.get(store.getObject(arrayID), index);
                Class retClass = store.getObject(arrayID).getClass().getComponentType(); // prevent auto-boxing influence

                if (ret == null) {
                    write(reference, "GetObjectArrayElement literalreturn null");
                } else if (retClass == Boolean.TYPE
                        || retClass == Byte.TYPE
                        || retClass == Short.TYPE
                        || retClass == Integer.TYPE
                        || retClass == Long.TYPE) {
                    write(reference, "GetObjectArrayElement literalreturn " + ret);
                } else if (retClass == Float.TYPE
                                || retClass == Double.TYPE) {
                    write(reference, "GetObjectArrayElement literalreturn " + String.format("%308.308e", ret));
                } else if (retClass == Character.TYPE) {
                    write(reference, "GetObjectArrayElement literalreturn " + (int) (Character) ret);
                } else {
                    // Track returned object.
                    store.reference(ret);
                    write(reference, "GetObjectArrayElement " + store.getIdentifier(ret));
                }

            } else if (message.startsWith("SetObjectArrayElement")) {
                String[] args = message.split(" ");
                Integer arrayID = parseCall(args[1], null, Integer.class);
                Integer index = parseCall(args[2], null, Integer.class);
                Integer objectID = parseCall(args[3], null, Integer.class);

                Object value = store.getObject(objectID);

                // Cast the object to appropriate type before insertion
                value = MethodOverloadResolver.getCostAndCastedObject(value, store.getObject(arrayID).getClass().getComponentType())[1];

                Array.set(store.getObject(arrayID), index, value);

                write(reference, "SetObjectArrayElement");
            } else if (message.startsWith("GetArrayLength")) {
                String[] args = message.split(" ");
                Integer arrayID = parseCall(args[1], null, Integer.class);

                Object o = store.getObject(arrayID);
                int len = 0;
                len = Array.getLength(o);

                write(reference, "GetArrayLength " + Array.getLength(o));
            } else if (message.startsWith("GetField")) {
                String[] args = message.split(" ");
                String type = parseCall(args[1], null, String.class);
                Integer objectID = parseCall(args[1], null, Integer.class);
                Integer fieldID = parseCall(args[2], null, Integer.class);

                final Object o = store.getObject(objectID);
                final Field f = (Field) store.getObject(fieldID);

                AccessControlContext acc = callContext != null ? callContext : getClosedAccessControlContext();
                checkPermission(src, o.getClass(), acc);

                Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
                    public Object run() {
                        try {
                            return f.get(o);
                        } catch (Throwable t) {
                            return t;
                        }
                    }
                }, acc);

                if (ret instanceof Throwable)
                    throw (Throwable) ret;

                if (ret == null) {
                    write(reference, "GetField literalreturn null");
                } else if (f.getType() == Boolean.TYPE
                        || f.getType() == Byte.TYPE
                        || f.getType() == Short.TYPE
                        || f.getType() == Integer.TYPE
                        || f.getType() == Long.TYPE) {
                    write(reference, "GetField literalreturn " + ret);
                } else if (f.getType() == Float.TYPE
                                || f.getType() == Double.TYPE) {
                    write(reference, "GetField literalreturn " + String.format("%308.308e", ret));
                } else if (f.getType() == Character.TYPE) {
                    write(reference, "GetField literalreturn " + (int) (Character) ret);
                } else {
                    // Track returned object.
                    store.reference(ret);
                    write(reference, "GetField " + store.getIdentifier(ret));
                }

            } else if (message.startsWith("GetObjectClass")) {
                int oid = Integer.parseInt(message.substring("GetObjectClass"
                                                .length() + 1));
                Class<?> c = store.getObject(oid).getClass();
                store.reference(c);

                write(reference, "GetObjectClass " + store.getIdentifier(c));
            } else if (message.startsWith("CallMethod") ||
                                           message.startsWith("CallStaticMethod")) {
                String[] args = message.split(" ");
                Integer objectID = parseCall(args[1], null, Integer.class);
                String methodName = parseCall(args[2], null, String.class);
                Object o = null;
                Class<?> c;

                if (message.startsWith("CallMethod")) {
                    o = store.getObject(objectID);
                    c = o.getClass();
                } else {
                    c = (Class<?>) store.getObject(objectID);
                }

                // length -3 to discard first 3, + 2 for holding object
                // and method name
                Object[] arguments = new Object[args.length - 1];
                arguments[0] = c;
                arguments[1] = methodName;
                for (int i = 0; i < args.length - 3; i++) {
                    arguments[i + 2] = store.getObject(parseCall(args[3 + i], null, Integer.class));
                    PluginDebug.debug("GOT ARG: ", arguments[i + 2]);
                }

                Object[] matchingMethodAndArgs = MethodOverloadResolver.getMatchingMethod(arguments);

                if (matchingMethodAndArgs == null) {
                    write(reference, "Error: No suitable method named " + methodName + " with matching args found");
                    return;
                }

                final Method m = (Method) matchingMethodAndArgs[0];
                Object[] castedArgs = new Object[matchingMethodAndArgs.length - 1];
                for (int i = 0; i < castedArgs.length; i++) {
                    castedArgs[i] = matchingMethodAndArgs[i + 1];
                }

                String collapsedArgs = "";
                for (Object arg : castedArgs) {
                    collapsedArgs += " " + arg;
                }

                PluginDebug.debug("Calling method ", m, " on object ", o
                                                , " (", c, ") with ", collapsedArgs);

                AccessControlContext acc = callContext != null ? callContext : getClosedAccessControlContext();
                checkPermission(src, c, acc);

                final Object[] fArguments = castedArgs;
                final Object callableObject = o;
                // Set the method accessible prior to calling. See:
                // http://forums.sun.com/thread.jspa?threadID=332001&start=15&tstart=0
                m.setAccessible(true);
                Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
                    public Object run() {
                        try {
                            return m.invoke(callableObject, fArguments);
                        } catch (Throwable t) {
                            return t;
                        }
                    }
                }, acc);

                if (ret instanceof Throwable)
                    throw (Throwable) ret;

                String retO;
                if (ret == null) {
                    retO = "null";
                } else {
                    retO = m.getReturnType().toString();
                }

                PluginDebug.debug("Calling ", m, " on ", o, " with "
                                                , collapsedArgs, " and that returned: ", ret
                                                , " of type ", retO);

                if (m.getReturnType().equals(java.lang.Void.class) ||
                                    m.getReturnType().equals(java.lang.Void.TYPE)) {
                    write(reference, "CallMethod literalreturn void");
                } else if (ret == null) {
                    write(reference, "CallMethod literalreturn null");
                } else if (m.getReturnType() == Boolean.TYPE
                                                || m.getReturnType() == Byte.TYPE
                                                || m.getReturnType() == Short.TYPE
                                                || m.getReturnType() == Integer.TYPE
                                                || m.getReturnType() == Long.TYPE) {
                    write(reference, "CallMethod literalreturn " + ret);
                } else if (m.getReturnType() == Float.TYPE
                                || m.getReturnType() == Double.TYPE) {
                    write(reference, "CallMethod literalreturn " + String.format("%308.308e", ret));
                } else if (m.getReturnType() == Character.TYPE) {
                    write(reference, "CallMethod literalreturn " + (int) (Character) ret);
                } else {
                    // Track returned object.
                    store.reference(ret);
                    write(reference, "CallMethod " + store.getIdentifier(ret));
                }
            } else if (message.startsWith("GetSuperclass")) {
                String[] args = message.split(" ");
                Integer classID = parseCall(args[1], null, Integer.class);
                Class<?> c = null;
                Class<?> ret = null;

                c = (Class) store.getObject(classID);
                ret = c.getSuperclass();
                store.reference(ret);

                write(reference, "GetSuperclass " + store.getIdentifier(ret));
            } else if (message.startsWith("IsAssignableFrom")) {
                String[] args = message.split(" ");
                Integer classID = parseCall(args[1], null, Integer.class);
                Integer superclassID = parseCall(args[2], null, Integer.class);

                boolean result = false;
                Class<?> clz = (Class<?>) store.getObject(classID);
                Class<?> sup = (Class<?>) store.getObject(superclassID);

                result = sup.isAssignableFrom(clz);

                write(reference, "IsAssignableFrom " + (result ? "1" : "0"));
            } else if (message.startsWith("IsInstanceOf")) {
                String[] args = message.split(" ");
                Integer objectID = parseCall(args[1], null, Integer.class);
                Integer classID = parseCall(args[2], null, Integer.class);

                boolean result = false;
                Object o = store.getObject(objectID);
                Class<?> c = (Class<?>) store.getObject(classID);

                result = c.isInstance(o);

                write(reference, "IsInstanceOf " + (result ? "1" : "0"));
            } else if (message.startsWith("GetStringUTFLength")) {
                String[] args = message.split(" ");
                Integer stringID = parseCall(args[1], null, Integer.class);

                String o = null;
                byte[] b = null;
                o = (String) store.getObject(stringID);
                b = o.getBytes("UTF-8");

                write(reference, "GetStringUTFLength " + o.length());
            } else if (message.startsWith("GetStringLength")) {
                String[] args = message.split(" ");
                Integer stringID = parseCall(args[1], null, Integer.class);

                String o = null;
                byte[] b = null;
                o = (String) store.getObject(stringID);
                b = o.getBytes("UTF-16LE");

                write(reference, "GetStringLength " + o.length());
            } else if (message.startsWith("GetStringUTFChars")) {
                String[] args = message.split(" ");
                Integer stringID = parseCall(args[1], null, Integer.class);

                String o = null;
                byte[] b = null;
                StringBuffer buf = null;
                o = (String) store.getObject(stringID);
                b = o.getBytes("UTF-8");
                buf = new StringBuffer(b.length * 2);
                buf.append(b.length);
                for (int i = 0; i < b.length; i++)
                    buf
                                                        .append(" "
                                                                        + Integer
                                                                                        .toString(((int) b[i]) & 0x0ff, 16));

                write(reference, "GetStringUTFChars " + buf);
            } else if (message.startsWith("GetStringChars")) {
                String[] args = message.split(" ");
                Integer stringID = parseCall(args[1], null, Integer.class);

                String o = null;
                byte[] b = null;
                StringBuffer buf = null;
                o = (String) store.getObject(stringID);
                // FIXME: LiveConnect uses UCS-2.
                b = o.getBytes("UTF-16LE");
                buf = new StringBuffer(b.length * 2);
                buf.append(b.length);
                for (int i = 0; i < b.length; i++)
                    buf
                                                        .append(" "
                                                                        + Integer
                                                                                        .toString(((int) b[i]) & 0x0ff, 16));

                PluginDebug.debug("Java: GetStringChars: ", o);
                PluginDebug.debug("  String BYTES: ", buf);
                write(reference, "GetStringChars " + buf);
            } else if (message.startsWith("GetToStringValue")) {
                String[] args = message.split(" ");
                Integer objectID = parseCall(args[1], null, Integer.class);

                String o = null;
                byte[] b = null;
                StringBuffer buf = null;
                o = store.getObject(objectID).toString();
                b = o.getBytes("UTF-8");
                buf = new StringBuffer(b.length * 2);
                buf.append(b.length);
                for (int i = 0; i < b.length; i++)
                    buf
                            .append(" "
                                    + Integer
                                            .toString(((int) b[i]) & 0x0ff, 16));

                write(reference, "GetToStringValue " + buf);
            } else if (message.startsWith("NewArray")) {
                String[] args = message.split(" ");
                String type = parseCall(args[1], null, String.class);
                Integer length = parseCall(args[2], null, Integer.class);

                Object newArray = null;

                Class c;
                if (type.equals("bool")) {
                    c = Boolean.class;
                } else if (type.equals("double")) {
                    c = Double.class;
                } else if (type.equals("int")) {
                    c = Integer.class;
                } else if (type.equals("string")) {
                    c = String.class;
                } else if (isInt(type)) {
                    c = (Class<?>) store.getObject(Integer.parseInt(type));
                } else {
                    c = JSObject.class;
                }

                if (args.length > 3)
                    newArray = Array.newInstance(c, new int[] { length, parseCall(args[3], null, Integer.class) });
                else
                    newArray = Array.newInstance(c, length);

                store.reference(newArray);
                write(reference, "NewArray " + store.getIdentifier(newArray));
            } else if (message.startsWith("HasMethod")) {
                String[] args = message.split(" ");
                Integer classNameID = parseCall(args[1], null, Integer.class);
                Integer methodNameID = parseCall(args[2], null, Integer.class);

                Class c = (Class<?>) store.getObject(classNameID);
                String methodName = (String) store.getObject(methodNameID);

                Method method = null;
                Method[] classMethods = c.getMethods();
                for (Method m : classMethods) {
                    if (m.getName().equals(methodName)) {
                        method = m;
                        break;
                    }
                }

                int hasMethod = (method != null) ? 1 : 0;

                write(reference, "HasMethod " + hasMethod);
            } else if (message.startsWith("HasPackage")) {
                String[] args = message.split(" ");
                Integer instance = parseCall(args[1], null, Integer.class);
                Integer nameID = parseCall(args[2], null, Integer.class);
                String pkgName = (String) store.getObject(nameID);

                Package pkg = Package.getPackage(pkgName);
                int hasPkg = (pkg != null) ? 1 : 0;

                write(reference, "HasPackage " + hasPkg);

            } else if (message.startsWith("HasField")) {
                String[] args = message.split(" ");
                Integer classNameID = parseCall(args[1], null, Integer.class);
                Integer fieldNameID = parseCall(args[2], null, Integer.class);

                Class c = (Class) store.getObject(classNameID);
                String fieldName = (String) store.getObject(fieldNameID);

                Field field = null;
                Field[] classFields = c.getFields();
                for (Field f : classFields) {
                    if (f.getName().equals(fieldName)) {
                        field = f;
                        break;
                    }
                }

                int hasField = (field != null) ? 1 : 0;

                write(reference, "HasField " + hasField);
            } else if (message.startsWith("NewObjectArray")) {
                String[] args = message.split(" ");
                Integer length = parseCall(args[1], null, Integer.class);
                Integer classID = parseCall(args[2], null, Integer.class);
                Integer objectID = parseCall(args[3], null, Integer.class);

                Object newArray = null;
                newArray = Array.newInstance((Class) store.getObject(classID),
                                                length);

                Object[] array = (Object[]) newArray;
                for (int i = 0; i < array.length; i++)
                    array[i] = store.getObject(objectID);
                store.reference(newArray);
                write(reference, "NewObjectArray "
                                                + store.getIdentifier(newArray));
            } else if (message.startsWith("NewObjectWithConstructor")) {

                String[] args = message.split(" ");
                Integer classID = parseCall(args[1], null, Integer.class);
                Integer methodID = parseCall(args[2], null, Integer.class);

                final Constructor m = (Constructor) store.getObject(methodID);
                Class[] argTypes = m.getParameterTypes();

                Object[] arguments = new Object[argTypes.length];
                for (int i = 0; i < argTypes.length; i++) {
                    arguments[i] = parseArgs(args[3 + i], argTypes[i]);
                }

                final Object[] fArguments = arguments;
                AccessControlContext acc = callContext != null ? callContext : getClosedAccessControlContext();

                Class c = (Class) store.getObject(classID);
                checkPermission(src, c, acc);

                Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
                    public Object run() {
                        try {
                            return m.newInstance(fArguments);
                        } catch (Throwable t) {
                            return t;
                        }
                    }
                }, acc);

                if (ret instanceof Throwable)
                    throw (Throwable) ret;

                store.reference(ret);

                write(reference, "NewObject " + store.getIdentifier(ret));

            } else if (message.startsWith("NewObject")) {
                String[] args = message.split(" ");
                Integer classID = parseCall(args[1], null, Integer.class);
                Class c = (Class) store.getObject(classID);
                final Constructor cons;
                final Object[] fArguments;

                Object[] arguments = new Object[args.length - 1];
                arguments[0] = c;
                for (int i = 0; i < args.length - 2; i++) {
                    arguments[i + 1] = store.getObject(parseCall(args[2 + i],
                            null, Integer.class));
                    PluginDebug.debug("GOT ARG: ", arguments[i + 1]);
                }

                Object[] matchingConstructorAndArgs = MethodOverloadResolver
                        .getMatchingConstructor(arguments);

                if (matchingConstructorAndArgs == null) {
                    write(reference,
                            "Error: No suitable constructor with matching args found");
                    return;
                }

                Object[] castedArgs = new Object[matchingConstructorAndArgs.length - 1];
                for (int i = 0; i < castedArgs.length; i++) {
                    castedArgs[i] = matchingConstructorAndArgs[i + 1];
                }

                cons = (Constructor) matchingConstructorAndArgs[0];
                fArguments = castedArgs;

                String collapsedArgs = "";
                for (Object arg : fArguments) {
                    collapsedArgs += " " + arg.toString();
                }

                PluginDebug.debug("Calling constructor on class ", c,
                                   " with ", collapsedArgs);

                AccessControlContext acc = callContext != null ? callContext : getClosedAccessControlContext();
                checkPermission(src, c, acc);

                Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
                    public Object run() {
                        try {
                            return cons.newInstance(fArguments);
                        } catch (Throwable t) {
                            return t;
                        }
                    }
                }, acc);

                if (ret instanceof Throwable)
                    throw (Throwable) ret;

                store.reference(ret);

                write(reference, "NewObject " + store.getIdentifier(ret));

            } else if (message.startsWith("NewStringUTF")) {
                PluginDebug.debug("MESSAGE: ", message);
                String[] args = message.split(" ");
                int length = new Integer(args[1]);
                byte[] byteArray = new byte[length];
                String ret = null;
                int i = 0;
                int j = 2;
                int c;
                while (i < length) {
                    c = Integer.parseInt(args[j++], 16);
                    byteArray[i++] = (byte) c;
                }

                ret = new String(byteArray, "UTF-8");
                PluginDebug.debug("NEWSTRINGUTF: ", ret);

                store.reference(ret);
                write(reference, "NewStringUTF " + store.getIdentifier(ret));
            } else if (message.startsWith("NewString")) {
                PluginDebug.debug("MESSAGE: ", message);
                String[] args = message.split(" ");
                Integer strlength = parseCall(args[1], null, Integer.class);
                int bytelength = 2 * strlength;
                byte[] byteArray = new byte[bytelength];
                String ret = null;
                for (int i = 0; i < strlength; i++) {
                    int c = parseCall(args[2 + i], null, Integer.class);
                    PluginDebug.debug("char ", i, " ", c);
                    // Low.
                    byteArray[2 * i] = (byte) (c & 0x0ff);
                    // High.
                    byteArray[2 * i + 1] = (byte) ((c >> 8) & 0x0ff);
                }
                ret = new String(byteArray, 0, bytelength, "UTF-16LE");
                PluginDebug.debug("NEWSTRING: ", ret);

                store.reference(ret);
                write(reference, "NewString " + store.getIdentifier(ret));

            } else if (message.startsWith("ExceptionOccurred")) {
                PluginDebug.debug("EXCEPTION: ", throwable);
                if (throwable != null)
                    store.reference(throwable);
                write(reference, "ExceptionOccurred "
                                                + store.getIdentifier(throwable));
            } else if (message.startsWith("ExceptionClear")) {
                if (throwable != null && store.contains(throwable))
                    store.unreference(store.getIdentifier(throwable));
                throwable = null;
                write(reference, "ExceptionClear");
            } else if (message.startsWith("DeleteGlobalRef")) {
                String[] args = message.split(" ");
                Integer id = parseCall(args[1], null, Integer.class);
                store.unreference(id);
                write(reference, "DeleteGlobalRef");
            } else if (message.startsWith("DeleteLocalRef")) {
                String[] args = message.split(" ");
                Integer id = parseCall(args[1], null, Integer.class);
                store.unreference(id);
                write(reference, "DeleteLocalRef");
            } else if (message.startsWith("NewGlobalRef")) {
                String[] args = message.split(" ");
                Integer id = parseCall(args[1], null, Integer.class);
                store.reference(store.getObject(id));
                write(reference, "NewGlobalRef " + id);
            } else if (message.startsWith("GetClassName")) {
                String[] args = message.split(" ");
                Integer objectID = parseCall(args[1], null, Integer.class);
                Object o = store.getObject(objectID);
                write(reference, "GetClassName " + o.getClass().getName());
            } else if (message.startsWith("GetClassID")) {
                String[] args = message.split(" ");
                Integer objectID = parseCall(args[1], null, Integer.class);
                store.reference(store.getObject(objectID).getClass());
                write(reference, "GetClassID " + store.getIdentifier(store.getObject(objectID).getClass()));
            }
        } catch (Throwable t) {
            t.printStackTrace();
            String msg = t.getCause() != null ? t.getCause().getMessage() : t.getMessage();

            // add an identifier string to let javaside know of the type of error
            // check for cause as well, since the top level exception will be InvocationTargetException in most cases
            if (t instanceof AccessControlException || t.getCause() instanceof AccessControlException) {
                msg = "LiveConnectPermissionNeeded " + msg;
            }

            write(reference, " Error " + msg);

            // ExceptionOccured is only called after Callmethod() by mozilla. So
            // for exceptions that are not related to CallMethod, we need a way
            // to log them. This is how we do it.. send an error message to the
            // c++ side to let it know that something went wrong, and it will do
            // the right thing to let mozilla know

            // Store the cause as the actual exception. This is needed because
            // the exception we get here will always be an
            // "InvocationTargetException" due to the use of reflection above
            if (message.startsWith("CallMethod") || message.startsWith("CallStaticMethod"))
                throwable = t.getCause();
        }

    }

    /**
     * Checks if the calling script is allowed to access the specified class
     *
     * @param jsSrc The source of the script
     * @param target The target class that the script is trying to access
     * @param acc AccessControlContext for this execution
     * @throws AccessControlException If the script has insufficient permissions
     */
    public void checkPermission(String jsSrc, Class target, AccessControlContext acc) throws AccessControlException {
        // NPRuntime does not allow cross-site calling. We therefore always
        // allow this, for the time being
        return;
    }

    private void write(int reference, String message) {
        PluginDebug.debug("appletviewer writing ", message);
        streamhandler.write("context " + identifier + " reference " + reference
                                + " " + message);
    }

    public void prePopulateLCClasses() {

        int classID;

        prepopulateClass("netscape/javascript/JSObject");
        classID = prepopulateClass("netscape/javascript/JSException");
        prepopulateMethod(classID, "<init>", "(Ljava/lang/String;Ljava/lang/String;ILjava/lang/String;I)");
        prepopulateMethod(classID, "<init>", "(ILjava/lang/Object;)");
        prepopulateField(classID, "lineno");
        prepopulateField(classID, "tokenIndex");
        prepopulateField(classID, "source");
        prepopulateField(classID, "filename");
        prepopulateField(classID, "wrappedExceptionType");
        prepopulateField(classID, "wrappedException");

        classID = prepopulateClass("netscape/javascript/JSUtil");
        prepopulateMethod(classID, "getStackTrace", "(Ljava/lang/Throwable;)");

        prepopulateClass("java/lang/Object");
        classID = prepopulateClass("java/lang/Class");
        prepopulateMethod(classID, "getMethods", "()");
        prepopulateMethod(classID, "getConstructors", "()");
        prepopulateMethod(classID, "getFields", "()");
        prepopulateMethod(classID, "getName", "()");
        prepopulateMethod(classID, "isArray", "()");
        prepopulateMethod(classID, "getComponentType", "()");
        prepopulateMethod(classID, "getModifiers", "()");

        classID = prepopulateClass("java/lang/reflect/Method");
        prepopulateMethod(classID, "getName", "()");
        prepopulateMethod(classID, "getParameterTypes", "()");
        prepopulateMethod(classID, "getReturnType", "()");
        prepopulateMethod(classID, "getModifiers", "()");

        classID = prepopulateClass("java/lang/reflect/Constructor");
        prepopulateMethod(classID, "getParameterTypes", "()");
        prepopulateMethod(classID, "getModifiers", "()");

        classID = prepopulateClass("java/lang/reflect/Field");
        prepopulateMethod(classID, "getName", "()");
        prepopulateMethod(classID, "getType", "()");
        prepopulateMethod(classID, "getModifiers", "()");

        classID = prepopulateClass("java/lang/reflect/Array");
        prepopulateMethod(classID, "newInstance", "(Ljava/lang/Class;I)");

        classID = prepopulateClass("java/lang/Throwable");
        prepopulateMethod(classID, "toString", "()");
        prepopulateMethod(classID, "getMessage", "()");

        classID = prepopulateClass("java/lang/System");
        prepopulateMethod(classID, "identityHashCode", "(Ljava/lang/Object;)");

        classID = prepopulateClass("java/lang/Boolean");
        prepopulateMethod(classID, "booleanValue", "()");
        prepopulateMethod(classID, "<init>", "(Z)");

        classID = prepopulateClass("java/lang/Double");
        prepopulateMethod(classID, "doubleValue", "()");
        prepopulateMethod(classID, "<init>", "(D)");

        classID = prepopulateClass("java/lang/Void");
        prepopulateField(classID, "TYPE");

        prepopulateClass("java/lang/String");
        prepopulateClass("java/applet/Applet");
    }

    private int prepopulateClass(String name) {
        name = name.replace('/', '.');
        ClassLoader cl = liveconnectLoader;
        Class c = null;

        try {
            c = cl.loadClass(name);
            store.reference(c);
        } catch (ClassNotFoundException cnfe) {
            // do nothing ... this should never happen
            cnfe.printStackTrace();
        }

        return store.getIdentifier(c);
    }

    private int prepopulateMethod(int classID, String methodName, String signatureStr) {
        Signature signature = parseCall(signatureStr, ((Class) store.getObject(classID)).getClassLoader(), Signature.class);
        Object[] a = signature.getClassArray();

        Class<?> c = (Class<?>) store.getObject(classID);
        Method m = null;
        Constructor cs = null;

        try {
            if (methodName.equals("<init>")
                                        || methodName.equals("<clinit>")) {
                cs = c.getConstructor(signature.getClassArray());
                store.reference(cs);
            } else {
                m = c.getMethod(methodName, signature.getClassArray());
                store.reference(m);
            }
        } catch (NoSuchMethodException e) {
            // should never happen
            e.printStackTrace();
        }

        return store.getIdentifier(m);
    }

    private int prepopulateField(int classID, String fieldName) {

        Class<?> c = (Class<?>) store.getObject(classID);
        Field f = null;
        try {
            f = c.getField(fieldName);
        } catch (SecurityException e) {
            // should never happen
            e.printStackTrace();
        } catch (NoSuchFieldException e) {
            // should never happen
            e.printStackTrace();
        }

        store.reference(f);
        return store.getIdentifier(f);
    }

    public void dumpStore() {
        store.dump();
    }

    public Object getObject(int identifier) {
        return store.getObject(identifier);
    }

    public int getIdentifier(Object o) {
        return store.getIdentifier(o);
    }

    public void store(Object o) {
        store.reference(o);
    }

    /**
     * Returns a "closed" AccessControlContext i.e. no permissions to get out of sandbox.
     */
    public AccessControlContext getClosedAccessControlContext() {
        // Deny everything
        Permissions p = new Permissions();
        ProtectionDomain pd = new ProtectionDomain(null, p);
        return new AccessControlContext(new ProtectionDomain[] { pd });
    }

    public AccessControlContext getAccessControlContext(String[] nsPrivilegeList, String src) {

        Permissions grantedPermissions = new Permissions();

        for (String privilege : nsPrivilegeList) {
            if (privilege.equals("UniversalBrowserRead")) {
                BrowserReadPermission bp = new BrowserReadPermission();
                grantedPermissions.add(bp);
            } else if (privilege.equals("UniversalJavaPermission")) {
                AllPermission ap = new AllPermission();
                grantedPermissions.add(ap);
            }
        }

        CodeSource cs = new CodeSource((URL) null, (java.security.cert.Certificate[]) null);

        if (src != null && src.length() > 0) {
            try {
                cs = new CodeSource(new URL(src + "/"), (java.security.cert.Certificate[]) null);
            } catch (MalformedURLException mfue) {
                // do nothing
            }

            if (src.equals("[System]"))
                grantedPermissions.add(new JSObjectCreatePermission());

        } else {
            JSObjectCreatePermission perm = new JSObjectCreatePermission();
            grantedPermissions.add(perm);
        }

        ProtectionDomain pd = new ProtectionDomain(cs, grantedPermissions, null, null);

        // Add to hashmap
        return new AccessControlContext(new ProtectionDomain[] { pd });
    }

    // private static final == inline
    private static final boolean isInt(Object o) {
        boolean isInt = false;

        try {
            Integer.parseInt((String) o);
            isInt = true;
        } catch (Exception e) {
            // don't care
        }

        return isInt;
    }

    class BrowserReadPermission extends BasicPermission {
        public BrowserReadPermission() {
            super("browserRead");
        }
    }

}
