/*

 * Copyright (c) 2008, 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

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 */

package sun.tracing.dtrace;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.InvocationTargetException;

import java.lang.annotation.Annotation;

import sun.tracing.ProviderSkeleton;

import sun.tracing.ProbeSkeleton;

import com.sun.tracing.Provider;

import com.sun.tracing.ProbeName;

import com.sun.tracing.dtrace.Attributes;

import com.sun.tracing.dtrace.ModuleName;

import com.sun.tracing.dtrace.FunctionName;

import com.sun.tracing.dtrace.StabilityLevel;

import com.sun.tracing.dtrace.DependencyClass;

import sun.misc.ProxyGenerator;

class DTraceProvider extends ProviderSkeleton {

    private Activation activation;

    private Object proxy;

    // For proxy generation

    private final static Class[] constructorParams = { InvocationHandler.class };

    private final String proxyClassNamePrefix = "$DTraceTracingProxy";

    static final String DEFAULT_MODULE = "java_tracing";

    static final String DEFAULT_FUNCTION = "unspecified";

    private static long nextUniqueNumber = 0;

    private static synchronized long getUniqueNumber() {

        return nextUniqueNumber++;

    }

    protected ProbeSkeleton createProbe(Method m) {

        return new DTraceProbe(proxy, m);

    }

    DTraceProvider(Class<? extends Provider> type) {

        super(type);

    }

    void setProxy(Object p) {

        proxy = p;

    }

    void setActivation(Activation a) {

        this.activation = a;

    }

    public void dispose() {

        if (activation != null) {

            activation.disposeProvider(this);

            activation = null;

        }

        super.dispose();

    }

    /**

     * Magic routine which creates an implementation of the user's interface.

     *

     * This method uses the ProxyGenerator directly to bypass the

     * java.lang.reflect.proxy cache so that we get a unique class each

     * time it's called and can't accidently reuse a $Proxy class.

     *

     * @return an implementation of the user's interface

     */

    @SuppressWarnings("unchecked")

    public <T extends Provider> T newProxyInstance() {

        /*

         * Choose a name for the proxy class to generate.

         */

        long num = getUniqueNumber();

        String proxyPkg = "";

        if (!Modifier.isPublic(providerType.getModifiers())) {

            String name = providerType.getName();

            int n = name.lastIndexOf('.');

            proxyPkg = ((n == -1) ? "" : name.substring(0, n + 1));

        }

        String proxyName = proxyPkg + proxyClassNamePrefix + num;

        /*

         * Generate the specified proxy class.

         */

        Class<?> proxyClass = null;

        byte[] proxyClassFile = ProxyGenerator.generateProxyClass(

                proxyName, new Class<?>[] { providerType });

        try {

            proxyClass = JVM.defineClass(

                providerType.getClassLoader(), proxyName,

                proxyClassFile, 0, proxyClassFile.length);

        } catch (ClassFormatError e) {

            /*

             * A ClassFormatError here means that (barring bugs in the

             * proxy class generation code) there was some other

             * invalid aspect of the arguments supplied to the proxy

             * class creation (such as virtual machine limitations

             * exceeded).

             */

            throw new IllegalArgumentException(e.toString());

        }

        /*

         * Invoke its constructor with the designated invocation handler.

         */

        try {

            Constructor cons = proxyClass.getConstructor(constructorParams);

            return (T)cons.newInstance(new Object[] { this });

        }

    }

    // In the normal case, the proxy object's method implementations will call

    // this method (it usually calls the ProviderSkeleton's version).  That

    // method uses the passed 'method' object to lookup the associated

    // 'ProbeSkeleton' and calls uncheckedTrigger() on that probe to cause the

    // probe to fire.  DTrace probes are different in that the proxy class's

    // methods are immediately overridden with native code to fire the probe

    // directly.  So this method should never get invoked.  We also wire up the

    // DTraceProbe.uncheckedTrigger() method to call the proxy method instead

    // of doing the work itself.

    public Object invoke(Object proxy, Method method, Object[] args) {

        if (method.getDeclaringClass() != providerType) {

            try {

                return method.invoke(this, args);

            } catch (IllegalAccessException e) {

                assert false;

            } catch (InvocationTargetException e) {

                assert false;

            }

        } else if (active) {

            assert false : "This method should have been overridden by the JVM";

        }

        return null;

    }

    public String getProviderName() {

        return super.getProviderName();

    }

    String getModuleName() {

        return getAnnotationString(

            providerType, ModuleName.class, DEFAULT_MODULE);

    }

    static String getProbeName(Method method) {

        return getAnnotationString(

            method, ProbeName.class, method.getName());

    }

    static String getFunctionName(Method method) {

        return getAnnotationString(

            method, FunctionName.class, DEFAULT_FUNCTION);

    }

    DTraceProbe[] getProbes() {

        return probes.values().toArray(new DTraceProbe[0]);

    }

    StabilityLevel getNameStabilityFor(Class<? extends Annotation> type) {

        Attributes attrs = (Attributes)getAnnotationValue(

            providerType, type, "value", null);

        if (attrs == null) {

            return StabilityLevel.PRIVATE;

        } else {

            return attrs.name();

        }

    }

    StabilityLevel getDataStabilityFor(Class<? extends Annotation> type) {

        Attributes attrs = (Attributes)getAnnotationValue(

            providerType, type, "value", null);

        if (attrs == null) {

            return StabilityLevel.PRIVATE;

        } else {

            return attrs.data();

        }

    }

    DependencyClass getDependencyClassFor(Class<? extends Annotation> type) {

        Attributes attrs = (Attributes)getAnnotationValue(

            providerType, type, "value", null);

        if (attrs == null) {

            return DependencyClass.UNKNOWN;

        } else {

            return attrs.dependency();

        }

    }

}