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ASM, a very small and fast Java bytecode manipulation framework
/***
* 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 {@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.
*/
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.
*/
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
// 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("[]");
}
}
}
}