org.glassfish.pfl/pfl-asm/4.1.0 : org/glassfish/pfl/objectweb/asm/util/TraceClassVisitor.java

TraceClassVisitor
https://github.com/eclipse-ee4j/orb-gmbal-pfl/pfl-asm: GMBAL- Java EE Primative Function Library (Eclipse Foundation)
EDL 1.0
Russell Gold
Yamini K B (Oracle Corporation)
ASM: a very small and fast Java bytecode manipulation framework
Copyright (c) 2000-2007 INRIA, France Telecom
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holders nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2007 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.glassfish.pfl.objectweb.asm.util;

import java.io.FileInputStream;
import java.io.PrintWriter;

import org.glassfish.pfl.objectweb.asm.AnnotationVisitor;
import org.glassfish.pfl.objectweb.asm.Attribute;
import org.glassfish.pfl.objectweb.asm.ClassReader;
import org.glassfish.pfl.objectweb.asm.ClassVisitor;
import org.glassfish.pfl.objectweb.asm.MethodVisitor;
import org.glassfish.pfl.objectweb.asm.Opcodes;
import org.glassfish.pfl.objectweb.asm.FieldVisitor;
import org.glassfish.pfl.objectweb.asm.signature.SignatureReader;

A ClassVisitor that prints a disassembled view of the classes it visits. This class visitor can be used alone (see the main method) to disassemble a class. It can also be used in the middle of class visitor chain to trace the class that is visited at a given point in this chain. This may be uselful for debugging purposes.  The trace printed when
visiting the Hello class is the following: 
 

// class version 49.0 (49)
// access flags 0x21
public class Hello {
 // compiled from: Hello.java
  // access flags 0x1
  public <init> ()V
    ALOAD 0
    INVOKESPECIAL java/lang/Object <init> ()V
    RETURN
    MAXSTACK = 1
    MAXLOCALS = 1
  // access flags 0x9
  public static main ([Ljava/lang/String;)V
    GETSTATIC java/lang/System out Ljava/io/PrintStream;
    LDC "hello"
    INVOKEVIRTUAL java/io/PrintStream println (Ljava/lang/String;)V
    RETURN
    MAXSTACK = 2
    MAXLOCALS = 1
}

 where Hello is defined by:  

public class Hello {
    public static void main(String[] args) {
        System.out.println("hello");
    }
}


Author: Eric Bruneton, Eugene Kuleshov/**
 * A {@link ClassVisitor} that prints a disassembled view of the classes it
 * visits. This class visitor can be used alone (see the {@link #main main}
 * method) to disassemble a class. It can also be used in the middle of class
 * visitor chain to trace the class that is visited at a given point in this
 * chain. This may be uselful for debugging purposes. <p> The trace printed when
 * visiting the <tt>Hello</tt> class is the following: <p> <blockquote>
 * 
 * <pre>
 * // class version 49.0 (49)
 * // access flags 0x21
 * public class Hello {
 *
 *  // compiled from: Hello.java
 *
 *   // access flags 0x1
 *   public &lt;init&gt; ()V
 *     ALOAD 0
 *     INVOKESPECIAL java/lang/Object &lt;init&gt; ()V
 *     RETURN
 *     MAXSTACK = 1
 *     MAXLOCALS = 1
 *
 *   // access flags 0x9
 *   public static main ([Ljava/lang/String;)V
 *     GETSTATIC java/lang/System out Ljava/io/PrintStream;
 *     LDC &quot;hello&quot;
 *     INVOKEVIRTUAL java/io/PrintStream println (Ljava/lang/String;)V
 *     RETURN
 *     MAXSTACK = 2
 *     MAXLOCALS = 1
 * }
 * </pre>
 * 
 * </blockquote> where <tt>Hello</tt> is defined by: <p> <blockquote>
 * 
 * <pre>
 * public class Hello {
 *
 *     public static void main(String[] args) {
 *         System.out.println(&quot;hello&quot;);
 *     }
 * }
 * </pre>
 * 
 * </blockquote>
 * 
 * @author Eric Bruneton
 * @author Eugene Kuleshov
 */
public class TraceClassVisitor extends TraceAbstractVisitor implements
        ClassVisitor
{

    The ClassVisitor to which this visitor delegates calls. May be null.
/**
     * The {@link ClassVisitor} to which this visitor delegates calls. May be
     * <tt>null</tt>.
     */
    protected final ClassVisitor cv;

    The print writer to be used to print the class.
/**
     * The print writer to be used to print the class.
     */
    protected final PrintWriter pw;

    Prints a disassembled view of the given class to the standard output. 
Usage: TraceClassVisitor [-debug] <fully qualified class name or class
file name >
Params: args – the command line arguments.
Throws: Exception – if the class cannot be found, or if an IO exception
        occurs./**
     * Prints a disassembled view of the given class to the standard output. <p>
     * Usage: TraceClassVisitor [-debug] &lt;fully qualified class name or class
     * file name &gt;
     * 
     * @param args the command line arguments.
     * 
     * @throws Exception if the class cannot be found, or if an IO exception
     *         occurs.
     */
    public static void main(final String[] args) throws Exception {
        int i = 0;
        int flags = ClassReader.SKIP_DEBUG;

        boolean ok = true;
        if (args.length < 1 || args.length > 2) {
            ok = false;
        }
        if (ok && "-debug".equals(args[0])) {
            i = 1;
            flags = 0;
            if (args.length != 2) {
                ok = false;
            }
        }
        if (!ok) {
            System.err.println("Prints a disassembled view of the given class.");
            System.err.println("Usage: TraceClassVisitor [-debug] "
                    + "<fully qualified class name or class file name>");
            return;
        }
        ClassReader cr;
        if (args[i].endsWith(".class") || args[i].indexOf('\\') > -1
                || args[i].indexOf('/') > -1)
        {
            cr = new ClassReader(new FileInputStream(args[i]));
        } else {
            cr = new ClassReader(args[i]);
        }
        cr.accept(new TraceClassVisitor(new PrintWriter(System.out)),
                getDefaultAttributes(),
                flags);
    }

    Constructs a new TraceClassVisitor. 
Params: pw – the print writer to be used to print the class./**
     * Constructs a new {@link TraceClassVisitor}.
     * 
     * @param pw the print writer to be used to print the class.
     */
    public TraceClassVisitor(final PrintWriter pw) {
        this(null, pw);
    }

    Constructs a new TraceClassVisitor. 
Params: cv – the ClassVisitor to which this visitor delegates calls. May be null.
pw – the print writer to be used to print the class./**
     * Constructs a new {@link TraceClassVisitor}.
     * 
     * @param cv the {@link ClassVisitor} to which this visitor delegates calls.
     *        May be <tt>null</tt>.
     * @param pw the print writer to be used to print the class.
     */
    public TraceClassVisitor(final ClassVisitor cv, final PrintWriter pw) {
        this.cv = cv;
        this.pw = pw;
    }

    // ------------------------------------------------------------------------
    // Implementation of the ClassVisitor interface
    // ------------------------------------------------------------------------

    public void visit(
        final int version,
        final int access,
        final String name,
        final String signature,
        final String superName,
        final String[] interfaces)
    {
        int major = version & 0xFFFF;
        int minor = version >>> 16;
        buf.setLength(0);
        buf.append("// class version ")
                .append(major)
                .append('.')
                .append(minor)
                .append(" (")
                .append(version)
                .append(")\n");
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            buf.append("// DEPRECATED\n");
        }
        buf.append("// access flags 0x").append(Integer.toHexString(access).toUpperCase()).append('\n');

        appendDescriptor(CLASS_SIGNATURE, signature);
        if (signature != null) {
            TraceSignatureVisitor sv = new TraceSignatureVisitor(access);
            SignatureReader r = new SignatureReader(signature);
            r.accept(sv);
            buf.append("// declaration: ")
                    .append(name)
                    .append(sv.getDeclaration())
                    .append('\n');
        }

        appendAccess(access & ~Opcodes.ACC_SUPER);
        if ((access & Opcodes.ACC_ANNOTATION) != 0) {
            buf.append("@interface ");
        } else if ((access & Opcodes.ACC_INTERFACE) != 0) {
            buf.append("interface ");
        } else if ((access & Opcodes.ACC_ENUM) == 0) {
            buf.append("class ");
        }
        appendDescriptor(INTERNAL_NAME, name);

        if (superName != null && !"java/lang/Object".equals(superName)) {
            buf.append(" extends ");
            appendDescriptor(INTERNAL_NAME, superName);
            buf.append(' ');
        }
        if (interfaces != null && interfaces.length > 0) {
            buf.append(" implements ");
            for (int i = 0; i < interfaces.length; ++i) {
                appendDescriptor(INTERNAL_NAME, interfaces[i]);
                buf.append(' ');
            }
        }
        buf.append(" {\n\n");

        text.add(buf.toString());

        if (cv != null) {
            cv.visit(version, access, name, signature, superName, interfaces);
        }
    }

    public void visitSource(final String file, final String debug) {
        buf.setLength(0);
        if (file != null) {
            buf.append(tab)
                    .append("// compiled from: ")
                    .append(file)
                    .append('\n');
        }
        if (debug != null) {
            buf.append(tab)
                    .append("// debug info: ")
                    .append(debug)
                    .append('\n');
        }
        if (buf.length() > 0) {
            text.add(buf.toString());
        }

        if (cv != null) {
            cv.visitSource(file, debug);
        }
    }

    public void visitOuterClass(
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        buf.append(tab).append("OUTERCLASS ");
        appendDescriptor(INTERNAL_NAME, owner);
        buf.append(' ');
        if (name != null) {
            buf.append(name).append(' ');
        }
        appendDescriptor(METHOD_DESCRIPTOR, desc);
        buf.append('\n');
        text.add(buf.toString());

        if (cv != null) {
            cv.visitOuterClass(owner, name, desc);
        }
    }

    public AnnotationVisitor visitAnnotation(
        final String desc,
        final boolean visible)
    {
        text.add("\n");
        AnnotationVisitor tav = super.visitAnnotation(desc, visible);
        if (cv != null) {
            ((TraceAnnotationVisitor) tav).av = cv.visitAnnotation(desc,
                    visible);
        }
        return tav;
    }

    public void visitAttribute(final Attribute attr) {
        text.add("\n");
        super.visitAttribute(attr);

        if (cv != null) {
            cv.visitAttribute(attr);
        }
    }

    public void visitInnerClass(
        final String name,
        final String outerName,
        final String innerName,
        final int access)
    {
        buf.setLength(0);
        buf.append(tab).append("// access flags 0x");
        buf.append(Integer.toHexString(access & ~Opcodes.ACC_SUPER).toUpperCase()).append('\n');
        buf.append(tab);
        appendAccess(access);
        buf.append("INNERCLASS ");
        appendDescriptor(INTERNAL_NAME, name);
        buf.append(' ');
        appendDescriptor(INTERNAL_NAME, outerName);
        buf.append(' ');
        appendDescriptor(INTERNAL_NAME, innerName);
        buf.append('\n');
        text.add(buf.toString());

        if (cv != null) {
            cv.visitInnerClass(name, outerName, innerName, access);
        }
    }

    public FieldVisitor visitField(
        final int access,
        final String name,
        final String desc,
        final String signature,
        final Object value)
    {
        buf.setLength(0);
        buf.append('\n');
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            buf.append(tab).append("// DEPRECATED\n");
        }
        buf.append(tab).append("// access flags 0x").append(Integer.toHexString(access).toUpperCase()).append('\n');
        if (signature != null) {
            buf.append(tab);
            appendDescriptor(FIELD_SIGNATURE, signature);

            TraceSignatureVisitor sv = new TraceSignatureVisitor(0);
            SignatureReader r = new SignatureReader(signature);
            r.acceptType(sv);
            buf.append(tab)
                    .append("// declaration: ")
                    .append(sv.getDeclaration())
                    .append('\n');
        }

        buf.append(tab);
        appendAccess(access);

        appendDescriptor(FIELD_DESCRIPTOR, desc);
        buf.append(' ').append(name);
        if (value != null) {
            buf.append(" = ");
            if (value instanceof String) {
                buf.append('\"').append(value).append('\"');
            } else {
                buf.append(value);
            }
        }

        buf.append('\n');
        text.add(buf.toString());

        TraceFieldVisitor tav = createTraceFieldVisitor();
        text.add(tav.getText());

        if (cv != null) {
            tav.fv = cv.visitField(access, name, desc, signature, value);
        }

        return tav;
    }

    public MethodVisitor visitMethod(
        final int access,
        final String name,
        final String desc,
        final String signature,
        final String[] exceptions)
    {
        buf.setLength(0);
        buf.append('\n');
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            buf.append(tab).append("// DEPRECATED\n");
        }
        buf.append(tab).append("// access flags 0x").append(Integer.toHexString(access).toUpperCase()).append('\n');

        if (signature != null) {
            buf.append(tab);
            appendDescriptor(METHOD_SIGNATURE, signature);

            TraceSignatureVisitor v = new TraceSignatureVisitor(0);
            SignatureReader r = new SignatureReader(signature);
            r.accept(v);
            String genericDecl = v.getDeclaration();
            String genericReturn = v.getReturnType();
            String genericExceptions = v.getExceptions();

            buf.append(tab)
                    .append("// declaration: ")
                    .append(genericReturn)
                    .append(' ')
                    .append(name)
                    .append(genericDecl);
            if (genericExceptions != null) {
                buf.append(" throws ").append(genericExceptions);
            }
            buf.append('\n');
        }

        buf.append(tab);
        appendAccess(access);
        if ((access & Opcodes.ACC_NATIVE) != 0) {
            buf.append("native ");
        }
        if ((access & Opcodes.ACC_VARARGS) != 0) {
            buf.append("varargs ");
        }
        if ((access & Opcodes.ACC_BRIDGE) != 0) {
            buf.append("bridge ");
        }

        buf.append(name);
        appendDescriptor(METHOD_DESCRIPTOR, desc);
        if (exceptions != null && exceptions.length > 0) {
            buf.append(" throws ");
            for (int i = 0; i < exceptions.length; ++i) {
                appendDescriptor(INTERNAL_NAME, exceptions[i]);
                buf.append(' ');
            }
        }

        buf.append('\n');
        text.add(buf.toString());

        TraceMethodVisitor tcv = createTraceMethodVisitor();
        text.add(tcv.getText());

        if (cv != null) {
            tcv.mv = cv.visitMethod(access, name, desc, signature, exceptions);
        }

        return tcv;
    }

    public void visitEnd() {
        text.add("}\n");

        print(pw);
        pw.flush();

        if (cv != null) {
            cv.visitEnd();
        }
    }

    // ------------------------------------------------------------------------
    // Utility methods
    // ------------------------------------------------------------------------

    protected TraceFieldVisitor createTraceFieldVisitor() {
        return new TraceFieldVisitor();
    }

    protected TraceMethodVisitor createTraceMethodVisitor() {
        return new TraceMethodVisitor();
    }

    Appends a string representation of the given access modifiers to buf. 
Params: access – some access modifiers./**
     * Appends a string representation of the given access modifiers to {@link
     * #buf buf}.
     * 
     * @param access some access modifiers.
     */
    private void appendAccess(final int access) {
        if ((access & Opcodes.ACC_PUBLIC) != 0) {
            buf.append("public ");
        }
        if ((access & Opcodes.ACC_PRIVATE) != 0) {
            buf.append("private ");
        }
        if ((access & Opcodes.ACC_PROTECTED) != 0) {
            buf.append("protected ");
        }
        if ((access & Opcodes.ACC_FINAL) != 0) {
            buf.append("final ");
        }
        if ((access & Opcodes.ACC_STATIC) != 0) {
            buf.append("static ");
        }
        if ((access & Opcodes.ACC_SYNCHRONIZED) != 0) {
            buf.append("synchronized ");
        }
        if ((access & Opcodes.ACC_VOLATILE) != 0) {
            buf.append("volatile ");
        }
        if ((access & Opcodes.ACC_TRANSIENT) != 0) {
            buf.append("transient ");
        }
        if ((access & Opcodes.ACC_ABSTRACT) != 0) {
            buf.append("abstract ");
        }
        if ((access & Opcodes.ACC_STRICT) != 0) {
            buf.append("strictfp ");
        }
        if ((access & Opcodes.ACC_ENUM) != 0) {
            buf.append("enum ");
        }
    }
}
Params:	args – the command line arguments.
Throws:	Exception – if the class cannot be found, or if an IO exception occurs.
/

org.glassfish.pfl/ pfl-asm/ 4.1.0/ org/glassfish/pfl/objectweb/asm/util/TraceClassVisitor.java
