ASM: a very small and fast Java bytecode manipulation framework
Copyright (c) 2000-2011 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) 2000-2011 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.objectweb.asm.util;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.signature.SignatureVisitor;

A SignatureVisitor that prints a disassembled view of the signature it visits. 
Author:
Eugene Kuleshov, Eric Bruneton/**
 * A {@link SignatureVisitor} that prints a disassembled view of the signature
 * it visits.
 * 
 * @author Eugene Kuleshov
 * @author Eric Bruneton
 */
public final class TraceSignatureVisitor extends SignatureVisitor {

    private final StringBuilder declaration;

    private boolean isInterface;

    private boolean seenFormalParameter;

    private boolean seenInterfaceBound;

    private boolean seenParameter;

    private boolean seenInterface;

    private StringBuilder returnType;

    private StringBuilder exceptions;

    
Stack used to keep track of class types that have arguments. Each element
of this stack is a boolean encoded in one bit. The top of the stack is
the lowest order bit. Pushing false = *2, pushing true = *2+1, popping =
/2.
/**
     * Stack used to keep track of class types that have arguments. Each element
     * of this stack is a boolean encoded in one bit. The top of the stack is
     * the lowest order bit. Pushing false = *2, pushing true = *2+1, popping =
     * /2.
     */
    private int argumentStack;

    
Stack used to keep track of array class types. Each element of this stack
is a boolean encoded in one bit. The top of the stack is the lowest order
bit. Pushing false = *2, pushing true = *2+1, popping = /2.
/**
     * Stack used to keep track of array class types. Each element of this stack
     * is a boolean encoded in one bit. The top of the stack is the lowest order
     * bit. Pushing false = *2, pushing true = *2+1, popping = /2.
     */
    private int arrayStack;

    private String separator = "";

    public TraceSignatureVisitor(final int access) {
        super(Opcodes.ASM5);
        isInterface = (access & Opcodes.ACC_INTERFACE) != 0;
        this.declaration = new StringBuilder();
    }

    private TraceSignatureVisitor(final StringBuilder buf) {
        super(Opcodes.ASM5);
        this.declaration = buf;
    }

    @Override
    public void visitFormalTypeParameter(final String name) {
        declaration.append(seenFormalParameter ? ", " : "<").append(name);
        seenFormalParameter = true;
        seenInterfaceBound = false;
    }

    @Override
    public SignatureVisitor visitClassBound() {
        separator = " extends ";
        startType();
        return this;
    }

    @Override
    public SignatureVisitor visitInterfaceBound() {
        separator = seenInterfaceBound ? ", " : " extends ";
        seenInterfaceBound = true;
        startType();
        return this;
    }

    @Override
    public SignatureVisitor visitSuperclass() {
        endFormals();
        separator = " extends ";
        startType();
        return this;
    }

    @Override
    public SignatureVisitor visitInterface() {
        separator = seenInterface ? ", " : isInterface ? " extends "
                : " implements ";
        seenInterface = true;
        startType();
        return this;
    }

    @Override
    public SignatureVisitor visitParameterType() {
        endFormals();
        if (seenParameter) {
            declaration.append(", ");
        } else {
            seenParameter = true;
            declaration.append('(');
        }
        startType();
        return this;
    }

    @Override
    public SignatureVisitor visitReturnType() {
        endFormals();
        if (seenParameter) {
            seenParameter = false;
        } else {
            declaration.append('(');
        }
        declaration.append(')');
        returnType = new StringBuilder();
        return new TraceSignatureVisitor(returnType);
    }

    @Override
    public SignatureVisitor visitExceptionType() {
        if (exceptions == null) {
            exceptions = new StringBuilder();
        } else {
            exceptions.append(", ");
        }
        // startType();
        return new TraceSignatureVisitor(exceptions);
    }

    @Override
    public void visitBaseType(final char descriptor) {
        switch (descriptor) {
        case 'V':
            declaration.append("void");
            break;
        case 'B':
            declaration.append("byte");
            break;
        case 'J':
            declaration.append("long");
            break;
        case 'Z':
            declaration.append("boolean");
            break;
        case 'I':
            declaration.append("int");
            break;
        case 'S':
            declaration.append("short");
            break;
        case 'C':
            declaration.append("char");
            break;
        case 'F':
            declaration.append("float");
            break;
        // case 'D':
        default:
            declaration.append("double");
            break;
        }
        endType();
    }

    @Override
    public void visitTypeVariable(final String name) {
        declaration.append(name);
        endType();
    }

    @Override
    public SignatureVisitor visitArrayType() {
        startType();
        arrayStack |= 1;
        return this;
    }

    @Override
    public void visitClassType(final String name) {
        if ("java/lang/Object".equals(name)) {
            // Map<java.lang.Object,java.util.List>
            // or
            // abstract public V get(Object key); (seen in Dictionary.class)
            // should have Object
            // but java.lang.String extends java.lang.Object is unnecessary
            boolean needObjectClass = argumentStack % 2 != 0 || seenParameter;
            if (needObjectClass) {
                declaration.append(separator).append(name.replace('/', '.'));
            }
        } else {
            declaration.append(separator).append(name.replace('/', '.'));
        }
        separator = "";
        argumentStack *= 2;
    }

    @Override
    public void visitInnerClassType(final String name) {
        if (argumentStack % 2 != 0) {
            declaration.append('>');
        }
        argumentStack /= 2;
        declaration.append('.');
        declaration.append(separator).append(name.replace('/', '.'));
        separator = "";
        argumentStack *= 2;
    }

    @Override
    public void visitTypeArgument() {
        if (argumentStack % 2 == 0) {
            ++argumentStack;
            declaration.append('<');
        } else {
            declaration.append(", ");
        }
        declaration.append('?');
    }

    @Override
    public SignatureVisitor visitTypeArgument(final char tag) {
        if (argumentStack % 2 == 0) {
            ++argumentStack;
            declaration.append('<');
        } else {
            declaration.append(", ");
        }

        if (tag == EXTENDS) {
            declaration.append("? extends ");
        } else if (tag == SUPER) {
            declaration.append("? super ");
        }

        startType();
        return this;
    }

    @Override
    public void visitEnd() {
        if (argumentStack % 2 != 0) {
            declaration.append('>');
        }
        argumentStack /= 2;
        endType();
    }

    public String getDeclaration() {
        return declaration.toString();
    }

    public String getReturnType() {
        return returnType == null ? null : returnType.toString();
    }

    public String getExceptions() {
        return exceptions == null ? null : exceptions.toString();
    }

    // -----------------------------------------------

    private void endFormals() {
        if (seenFormalParameter) {
            declaration.append('>');
            seenFormalParameter = false;
        }
    }

    private void startType() {
        arrayStack *= 2;
    }

    private void endType() {
        if (arrayStack % 2 == 0) {
            arrayStack /= 2;
        } else {
            while (arrayStack % 2 != 0) {
                arrayStack /= 2;
                declaration.append("[]");
            }
        }
    }
}