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	/*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	* This file is available under and governed by the GNU General Public
	* License version 2 only, as published by the Free Software Foundation.
	* However, the following notice accompanied the original version of this
	* file:
	*
	* 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 jdk.internal.org.objectweb.asm.util;

	import java.util.Collections;
	import java.util.HashMap;
	import java.util.Map;
	import jdk.internal.org.objectweb.asm.Opcodes;
	import jdk.internal.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 ";

	private static final Map<Character, String> BASE_TYPES;

	static {
	HashMap<Character, String> baseTypes = new HashMap<>();
	baseTypes.put('Z', "boolean");
	baseTypes.put('B', "byte");
	baseTypes.put('C', "char");
	baseTypes.put('S', "short");
	baseTypes.put('I', "int");
	baseTypes.put('J', "long");
	baseTypes.put('F', "float");
	baseTypes.put('D', "double");
	baseTypes.put('V', "void");
	BASE_TYPES = Collections.unmodifiableMap(baseTypes);
	}

	/** 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(/* latest api = */ Opcodes.ASM8);
	this.isInterface = (accessFlags & Opcodes.ACC_INTERFACE) != 0;
	this.declaration = new StringBuilder();
	}

	private TraceSignatureVisitor(final StringBuilder stringBuilder) {
	super(/* latest api = */ Opcodes.ASM8);
	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) {
	String baseType = BASE_TYPES.get(descriptor);
	if (baseType == null) {
	throw new IllegalArgumentException();
	}
	declaration.append(baseType);
	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<java.lang.Object,java.util.List>' or 'public abstract 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();
	}

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

	/**
	* Returns the Java generic type declaration corresponding to the visited signature.
	*
	* @return the Java generic type declaration corresponding to the visited signature.
	*/
	public String getDeclaration() {
	return declaration.toString();
	}

	/**
	* Returns the Java generic method return type declaration corresponding to the visited signature.
	*
	* @return the Java generic method return type declaration corresponding to the visited signature.
	*/
	public String getReturnType() {
	return returnType == null ? null : returnType.toString();
	}

	/**
	* Returns the Java generic exception types declaration corresponding to the visited signature.
	*
	* @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("[]");
	}
	}
	}
	}

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