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Utilities for 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 builds the Java generic type declaration corresponding to the
* signature it visits.
*
* @author Eugene Kuleshov
* @author Eric Bruneton
*/
public final class TraceSignatureVisitor extends SignatureVisitor {
private static final String COMMA_SEPARATOR = ", ";
private static final String EXTENDS_SEPARATOR = " extends ";
private static final String IMPLEMENTS_SEPARATOR = " implements ";
/** Whether the visited signature is a class signature of a Java interface. */
private final boolean isInterface;
/** The Java generic type declaration corresponding to the visited signature. */
private final StringBuilder declaration;
/** The Java generic method return type declaration corresponding to the visited signature. */
private StringBuilder returnType;
/** The Java generic exception types declaration corresponding to the visited signature. */
private StringBuilder exceptions;
/** Whether {@link #visitFormalTypeParameter} has been called. */
private boolean formalTypeParameterVisited;
/** Whether {@link #visitInterfaceBound} has been called. */
private boolean interfaceBoundVisited;
/** Whether {@link #visitParameterType} has been called. */
private boolean parameterTypeVisited;
/** Whether {@link #visitInterface} has been called. */
private boolean interfaceVisited;
/**
* The 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 least significant bit. Pushing false
* = *2, pushing true = *2+1, popping = /2.
*/
private int argumentStack;
/**
* The 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;
/** The separator to append before the next visited class or inner class type. */
private String separator = "";
/**
* Constructs a new {@link TraceSignatureVisitor}.
*
* @param accessFlags for class type signatures, the access flags of the class.
*/
public TraceSignatureVisitor(final int accessFlags) {
super(Opcodes.ASM6);
this.isInterface = (accessFlags & Opcodes.ACC_INTERFACE) != 0;
this.declaration = new StringBuilder();
}
private TraceSignatureVisitor(final StringBuilder stringBuilder) {
super(Opcodes.ASM6);
this.isInterface = false;
this.declaration = stringBuilder;
}
@Override
public void visitFormalTypeParameter(final String name) {
declaration.append(formalTypeParameterVisited ? COMMA_SEPARATOR : "<").append(name);
formalTypeParameterVisited = true;
interfaceBoundVisited = false;
}
@Override
public SignatureVisitor visitClassBound() {
separator = EXTENDS_SEPARATOR;
startType();
return this;
}
@Override
public SignatureVisitor visitInterfaceBound() {
separator = interfaceBoundVisited ? COMMA_SEPARATOR : EXTENDS_SEPARATOR;
interfaceBoundVisited = true;
startType();
return this;
}
@Override
public SignatureVisitor visitSuperclass() {
endFormals();
separator = EXTENDS_SEPARATOR;
startType();
return this;
}
@Override
public SignatureVisitor visitInterface() {
if (interfaceVisited) {
separator = COMMA_SEPARATOR;
} else {
separator = isInterface ? EXTENDS_SEPARATOR : IMPLEMENTS_SEPARATOR;
interfaceVisited = true;
}
startType();
return this;
}
@Override
public SignatureVisitor visitParameterType() {
endFormals();
if (parameterTypeVisited) {
declaration.append(COMMA_SEPARATOR);
} else {
declaration.append('(');
parameterTypeVisited = true;
}
startType();
return this;
}
@Override
public SignatureVisitor visitReturnType() {
endFormals();
if (parameterTypeVisited) {
parameterTypeVisited = 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(COMMA_SEPARATOR);
}
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':
declaration.append("double");
break;
default:
throw new IllegalArgumentException();
}
endType();
}
@Override
public void visitTypeVariable(final String name) {
declaration.append(separator).append(name);
separator = "";
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);' should have
// Object 'but java.lang.String extends java.lang.Object' is unnecessary.
boolean needObjectClass = argumentStack % 2 != 0 || parameterTypeVisited;
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(COMMA_SEPARATOR);
}
declaration.append('?');
}
@Override
public SignatureVisitor visitTypeArgument(final char tag) {
if (argumentStack % 2 == 0) {
++argumentStack;
declaration.append('<');
} else {
declaration.append(COMMA_SEPARATOR);
}
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();
}
// -----------------------------------------------------------------------------------------------
/** @return the Java generic type declaration corresponding to the visited signature. */
public String getDeclaration() {
return declaration.toString();
}
/**
* @return the Java generic method return type declaration corresponding to the visited signature.
*/
public String getReturnType() {
return returnType == null ? null : returnType.toString();
}
/**
* @return the Java generic exception types declaration corresponding to the visited signature.
*/
public String getExceptions() {
return exceptions == null ? null : exceptions.toString();
}
// -----------------------------------------------------------------------------------------------
private void endFormals() {
if (formalTypeParameterVisited) {
declaration.append('>');
formalTypeParameterVisited = false;
}
}
private void startType() {
arrayStack *= 2;
}
private void endType() {
if (arrayStack % 2 == 0) {
arrayStack /= 2;
} else {
while (arrayStack % 2 != 0) {
arrayStack /= 2;
declaration.append("[]");
}
}
}
}