org.glassfish.pfl.tf.tools.enhancer.Transformer.java Source code

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package org.glassfish.pfl.tf.tools.enhancer;

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright (c) 1997-2010,2017 Oracle and/or its affiliates. All rights reserved.
 * 
 * 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
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * 
 * GPL Classpath Exception:
 * 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.
 * 
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 * 
 * Contributor(s):
 * 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 don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  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 made subject to such option by the copyright
 * holder.
 */

import org.glassfish.pfl.basic.func.UnaryFunction;
import org.glassfish.pfl.tf.spi.EnhancedClassData;
import org.glassfish.pfl.tf.spi.EnhancedClassDataASMImpl;
import org.glassfish.pfl.tf.spi.TimingPointType;
import org.glassfish.pfl.tf.spi.TraceEnhancementException;
import org.glassfish.pfl.tf.spi.Util;
import org.glassfish.pfl.tf.timer.spi.TimerFactoryBuilder;
import org.glassfish.pfl.tf.timer.spi.TimingInfoProcessor;
import org.objectweb.asm.ClassAdapter;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.ClassNode;

import java.util.Iterator;
import java.util.Set;

/** ClassFile enhancer for the tracing facility.  This modifies the bytecode
 * for an applicable class, then returns the updated bytecode.
 * Makes extensive use of the ASM library.
 *
 * This is split into two parts.  The first part modifies the schema
 * of the class as follows:
 * <ul>
 * <li>Adds static fields as required for the SynchronizedHolder<MethodMonitor> 
 * instances.
 * <li>Modifies the static initializer to set up the new fields, and register
 * the class with the MethodMonitorRegistry.  This also constructs the list
 * of method names, which is needed by the second part.
 * <li>Re-writes all @InfoMethod methods to take two extra parameters at the
 * end of their argument lists.
 * <li>Re-writes all calls to @InfoMethod methods to supply the two extra 
 * parameters to all calls.
 * <li>Checks that @InfoMethod methods (which must be private) are only called
 * from MM annotated methods.
 * </ul>
 * <p>
 * The second part modifies the MM annotated methods as follows:
 * <li>Adds a preamble to set up some local variables, and to call 
 * the MethodMonitor.enter method when active.
 * <li>Adds a finally block at the end of the method that handles calling
 * MethodMonitor.exit whenever an exception is thrown or propagated from the
 * body of the method.
 * <li>Modifies all exit point in the method as follows:
 * <ul>
 * <li>If the exit point is a return, call MethodMonitor.exit before the return.
 * <li>If the exit point is a throw, call MethodMonitor.exception before the throw.
 * </ul>
 * </ul>
 * <p>
 * Note that the second part could be run in a ClassFileTransformer or ClassLoader
 * if desired, since this design enhances the class files in place for the first
 * part.
 *
 * @author ken
 */
public class Transformer implements UnaryFunction<byte[], byte[]> {
    private final Util util;
    private final EnhanceTool.ProcessingMode mode;
    private final TimingInfoProcessor tip;
    private final Set<String> annotationNames;

    // Initialized in the evaluate method.
    private EnhancedClassData ecd = null;

    Transformer(Util util, EnhanceTool.ProcessingMode mode, TimingInfoProcessor tip, Set<String> anames) {

        this.util = util;
        this.mode = mode;
        this.tip = tip;
        this.annotationNames = anames;
    }

    private String getSuffix(String str) {
        String result = str;
        final int index = str.lastIndexOf('/');
        if (index >= 0) {
            result = result.substring(index + 1);
        }
        return result;
    }

    private void processTimers() {
        final Iterator<String> descriptions = ecd.getDescriptions().iterator();
        final Iterator<String> names = ecd.getTimingPointNames().iterator();
        final Iterator<TimingPointType> tpts = ecd.getTimingPointTypes().iterator();
        final Iterator<String> groups = ecd.getMethodMMAnnotationName().iterator();

        final Set<String> classAnnoNames = ecd.getAnnotationToHolderName().keySet();

        while (descriptions.hasNext()) {
            final String desc = descriptions.next();
            final String name = names.next();
            final TimingPointType tpt = tpts.next();
            final String group = groups.next();

            if (tpt != TimingPointType.NONE) {
                final String cname = getSuffix(ecd.getClassName());
                final String timerName = TimerFactoryBuilder.getTimerName(cname, name);

                tip.addTimer(timerName, desc);

                if (group == null) {
                    for (String str : classAnnoNames) {
                        tip.containedIn(timerName, getSuffix(str));
                    }
                } else {
                    tip.containedIn(timerName, getSuffix(group));
                }
            }
        }
    }

    public byte[] evaluate(final byte[] arg) {
        final ClassNode cn = new ClassNode();
        final ClassReader cr = new ClassReader(arg);
        cr.accept(cn, ClassReader.SKIP_FRAMES);

        // Ignore annotations and interfaces.
        if (util.hasAccess(cn.access, Opcodes.ACC_ANNOTATION) || util.hasAccess(cn.access, Opcodes.ACC_INTERFACE)) {
            return null;
        }

        try {
            ecd = new EnhancedClassDataASMImpl(util, annotationNames, cn);

            // If this class is not annotated as a traced class, ignore it.
            if (!ecd.isTracedClass()) {
                return null;
            }

            processTimers();

            byte[] phase1 = null;
            if ((mode == EnhanceTool.ProcessingMode.UpdateSchemas)
                    || (mode == EnhanceTool.ProcessingMode.TraceEnhance)) {
                phase1 = util.transform(false, arg, new UnaryFunction<ClassVisitor, ClassAdapter>() {
                    public ClassAdapter evaluate(ClassVisitor arg) {
                        return new ClassEnhancer(util, ecd, arg);
                    }
                });
            }

            // Only communication from part 1 to part2 is a byte[] and
            // the EnhancedClassData.  A runtime version can be regenerated
            // as above from the byte[] from the class file as it is presented
            // to a ClassFileTransformer.
            //     Implementation note: runtime would keep byte[] stored of
            //     original version whenever tracing is enabled, so that
            //     disabling tracing simply means using a ClassFileTransformer
            //     to get back to the original code.
            //
            // Then add tracing code (part 2).
            //     This is a pure visitor using the AdviceAdapter.
            //     It must NOT modify its input visitor (or you get an
            //     infinite series of calls to onMethodExit...)

            if (mode == EnhanceTool.ProcessingMode.TraceEnhance) {
                final byte[] phase2 = util.transform(util.getDebug(), phase1,
                        new UnaryFunction<ClassVisitor, ClassAdapter>() {

                            public ClassAdapter evaluate(ClassVisitor arg) {
                                return new ClassTracer(util, ecd, arg);
                            }
                        });

                return phase2;
            } else {
                return phase1;
            }
        } catch (TraceEnhancementException exc) {
            if (util.getDebug()) {
                util.info(1, "Could not enhance file: " + exc);
            }

            return null;
        }
    }
}