/**

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 2013-2014 Oracle and/or its affiliates. All rights reserved.

 *

 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.

 * Other names may be trademarks of their respective owners.

 *

 * The contents of this file are subject to the terms of either the GNU

 * General Public License Version 2 only ("GPL") or the Common

 * Development and Distribution License("CDDL") (collectively, the

 * "License"). You may not use this file except in compliance with the

 * License. You can obtain a copy of the License at

 * http://www.netbeans.org/cddl-gplv2.html

 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

 * specific language governing permissions and limitations under the

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 * Notice in each file and include the License file at

 * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

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

 * by Oracle in the GPL Version 2 section of the License file that

 * accompanied this code. If applicable, add the following below the

 * License Header, with the fields enclosed by brackets [] replaced by

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 * Contributor(s):

 *

 * The Original Software is NetBeans. The Initial Developer of the Original

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 * If you wish your version of this file to be governed by only the CDDL

 * or only the GPL Version 2, indicate your decision by adding

 * "[Contributor] elects to include this software in this distribution

 * under the [CDDL or GPL Version 2] license." If you do not indicate a

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 * However, if you add GPL Version 2 code and therefore, elected the GPL

 * Version 2 license, then the option applies only if the new code is

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 */

package org.netbeans.html.equinox.agentclass;

import java.lang.instrument.ClassDefinition;

import java.lang.instrument.ClassFileTransformer;

import java.lang.instrument.IllegalClassFormatException;

import java.lang.instrument.Instrumentation;

import java.lang.instrument.UnmodifiableClassException;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.security.ProtectionDomain;

import java.util.Collection;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import java.util.concurrent.CopyOnWriteArrayList;

import java.util.jar.JarFile;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

final class NbInstrumentation implements Instrumentation {

    private static final Logger LOG = Logger.getLogger(NbInstrumentation.class.getName());

    private static final Object LOCK = new Object();

    private static volatile Collection<NbInstrumentation> ACTIVE;

    private final List<ClassFileTransformer> transformers = new CopyOnWriteArrayList<ClassFileTransformer>();

    private static final ThreadLocal<Boolean> IN = new ThreadLocal<Boolean>();

    static NbInstrumentation registerAgent(ClassLoader l, String agentClassName) {

        try {

            return registerImpl(agentClassName, l);

        } catch (Throwable ex) {

            LOG.log(Level.WARNING, "Cannot register " + agentClassName, ex);

            return null;

        }

    }

    static void unregisterAgent(NbInstrumentation instr) {

        synchronized (LOCK) {

            if (ACTIVE != null) {

                Collection<NbInstrumentation> clone = new HashSet<NbInstrumentation>();

                clone.addAll(ACTIVE);

                clone.remove(instr);

                ACTIVE = clone;

            }

        }

    }

    private static NbInstrumentation registerImpl(String agentClassName, ClassLoader l) throws ClassNotFoundException, IllegalArgumentException, NoSuchMethodException, SecurityException, IllegalAccessException, InvocationTargetException {

        final NbInstrumentation inst = new NbInstrumentation();

        synchronized (LOCK) {

            if (ACTIVE == null) {

                ACTIVE = new HashSet<NbInstrumentation>();

            } else {

                Set<NbInstrumentation> s = new HashSet<NbInstrumentation>();

                s.addAll(ACTIVE);

                ACTIVE = s;

            }

            ACTIVE.add(inst);

        }

        Class<?> agentClass = Class.forName(agentClassName, true, l);

        try {

            Method m = agentClass.getMethod("agentmain", String.class, Instrumentation.class); // NOI18N

            m.invoke(null, "", inst);

        } catch (NoSuchMethodException ex) {

            Method m = agentClass.getMethod("agentmain", String.class); // NOI18N

            m.invoke(null, "");

        }

        return inst;

    }

    public static byte[] patchByteCode(ClassLoader l, String className, ProtectionDomain pd, byte[] arr) throws IllegalClassFormatException {

        if (ACTIVE == null) {

            return arr;

        }

        if (Boolean.TRUE.equals(IN.get())) {

            return arr;

        }

        try {

            IN.set(Boolean.TRUE);

            for (NbInstrumentation inst : ACTIVE) {

                for (ClassFileTransformer t : inst.transformers) {

                    arr = t.transform(l, className, null, pd, arr);

                }

            }

        } finally {

            IN.set(null);

        }

        return arr;

    }

    //

    // Instrumentation methods

    //

    @Override

    public void addTransformer(ClassFileTransformer transformer, boolean canRetransform) {

        transformers.add(transformer);

    }

    @Override

    public void addTransformer(ClassFileTransformer transformer) {

        transformers.add(transformer);

    }

    @Override

    public boolean removeTransformer(ClassFileTransformer transformer) {

        return transformers.remove(transformer);

    }

    @Override

    public boolean isRetransformClassesSupported() {

        return false;

    }

    @Override

    public void retransformClasses(Class<?>... classes) throws UnmodifiableClassException {

        throw new UnmodifiableClassException();

    }

    @Override

    public boolean isRedefineClassesSupported() {

        return false;

    }

    @Override

    public void redefineClasses(ClassDefinition... definitions) throws ClassNotFoundException, UnmodifiableClassException {

        throw new UnmodifiableClassException();

    }

    @Override

    public boolean isModifiableClass(Class<?> theClass) {

        return false;

    }

    @Override

    public Class[] getAllLoadedClasses() {

        return new Class[0];

    }

    @Override

    public Class[] getInitiatedClasses(ClassLoader loader) {

        return new Class[0];

    }

    @Override

    public long getObjectSize(Object objectToSize) {

        return 42;

    }

    @Override

    public void appendToBootstrapClassLoaderSearch(JarFile jarfile) {

    }

    @Override

    public void appendToSystemClassLoaderSearch(JarFile jarfile) {

        throw new UnsupportedOperationException();

    }

    @Override

    public boolean isNativeMethodPrefixSupported() {

        return false;

    }

    @Override

    public void setNativeMethodPrefix(ClassFileTransformer transformer, String prefix) {

        throw new UnsupportedOperationException();

    }

}