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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.tree.analysis;

	import java.util.List;
	import jdk.internal.org.objectweb.asm.Type;

	/**
	* An extended {@link BasicVerifier} that performs more precise verifications. This verifier
	* computes exact class types, instead of using a single "object reference" type (as done in {@link
	* BasicVerifier}).
	*
	* @author Eric Bruneton
	* @author Bing Ran
	*/
	public class SimpleVerifier extends BasicVerifier {

	/** The type of the class that is verified. */
	private final Type currentClass;

	/** The type of the super class of the class that is verified. */
	private final Type currentSuperClass;

	/** The types of the interfaces directly implemented by the class that is verified. */
	private final List<Type> currentClassInterfaces;

	/** Whether the class that is verified is an interface. */
	private final boolean isInterface;

	/** The loader to use to load the referenced classes. */
	private ClassLoader loader = getClass().getClassLoader();

	/**
	* Constructs a new {@link SimpleVerifier}. <i>Subclasses must not use this constructor</i>.
	* Instead, they must use the {@link #SimpleVerifier(int, Type, Type, List, boolean)} version.
	*/
	public SimpleVerifier() {
	this(null, null, false);
	}

	/**
	* Constructs a new {@link SimpleVerifier} to verify a specific class. This class will not be
	* loaded into the JVM since it may be incorrect. <i>Subclasses must not use this constructor</i>.
	* Instead, they must use the {@link #SimpleVerifier(int, Type, Type, List, boolean)} version.
	*
	* @param currentClass the type of the class to be verified.
	* @param currentSuperClass the type of the super class of the class to be verified.
	* @param isInterface whether the class to be verifier is an interface.
	*/
	public SimpleVerifier(
	final Type currentClass, final Type currentSuperClass, final boolean isInterface) {
	this(currentClass, currentSuperClass, null, isInterface);
	}

	/**
	* Constructs a new {@link SimpleVerifier} to verify a specific class. This class will not be
	* loaded into the JVM since it may be incorrect. <i>Subclasses must not use this constructor</i>.
	* Instead, they must use the {@link #SimpleVerifier(int, Type, Type, List, boolean)} version.
	*
	* @param currentClass the type of the class to be verified.
	* @param currentSuperClass the type of the super class of the class to be verified.
	* @param currentClassInterfaces the types of the interfaces directly implemented by the class to
	* be verified.
	* @param isInterface whether the class to be verifier is an interface.
	*/
	public SimpleVerifier(
	final Type currentClass,
	final Type currentSuperClass,
	final List<Type> currentClassInterfaces,
	final boolean isInterface) {
	this(
	/* latest api = */ ASM8,
	currentClass,
	currentSuperClass,
	currentClassInterfaces,
	isInterface);
	if (getClass() != SimpleVerifier.class) {
	throw new IllegalStateException();
	}
	}

	/**
	* Constructs a new {@link SimpleVerifier} to verify a specific class. This class will not be
	* loaded into the JVM since it may be incorrect.
	*
	* @param api the ASM API version supported by this verifier. Must be one of {@link
	* jdk.internal.org.objectweb.asm.Opcodes#ASM4}, {@link jdk.internal.org.objectweb.asm.Opcodes#ASM5}, {@link
	* jdk.internal.org.objectweb.asm.Opcodes#ASM6}, {@link jdk.internal.org.objectweb.asm.Opcodes#ASM7} or {@link
	* jdk.internal.org.objectweb.asm.Opcodes#ASM8}.
	* @param currentClass the type of the class to be verified.
	* @param currentSuperClass the type of the super class of the class to be verified.
	* @param currentClassInterfaces the types of the interfaces directly implemented by the class to
	* be verified.
	* @param isInterface whether the class to be verifier is an interface.
	*/
	protected SimpleVerifier(
	final int api,
	final Type currentClass,
	final Type currentSuperClass,
	final List<Type> currentClassInterfaces,
	final boolean isInterface) {
	super(api);
	this.currentClass = currentClass;
	this.currentSuperClass = currentSuperClass;
	this.currentClassInterfaces = currentClassInterfaces;
	this.isInterface = isInterface;
	}

	/**
	* Sets the <code>ClassLoader</code> to be used in {@link #getClass}.
	*
	* @param loader the <code>ClassLoader</code> to use.
	*/
	public void setClassLoader(final ClassLoader loader) {
	this.loader = loader;
	}

	@Override
	public BasicValue newValue(final Type type) {
	if (type == null) {
	return BasicValue.UNINITIALIZED_VALUE;
	}

	boolean isArray = type.getSort() == Type.ARRAY;
	if (isArray) {
	switch (type.getElementType().getSort()) {
	case Type.BOOLEAN:
	case Type.CHAR:
	case Type.BYTE:
	case Type.SHORT:
	return new BasicValue(type);
	default:
	break;
	}
	}

	BasicValue value = super.newValue(type);
	if (BasicValue.REFERENCE_VALUE.equals(value)) {
	if (isArray) {
	value = newValue(type.getElementType());
	StringBuilder descriptor = new StringBuilder();
	for (int i = 0; i < type.getDimensions(); ++i) {
	descriptor.append('[');
	}
	descriptor.append(value.getType().getDescriptor());
	value = new BasicValue(Type.getType(descriptor.toString()));
	} else {
	value = new BasicValue(type);
	}
	}
	return value;
	}

	@Override
	protected boolean isArrayValue(final BasicValue value) {
	Type type = value.getType();
	return type != null && (type.getSort() == Type.ARRAY \|\| type.equals(NULL_TYPE));
	}

	@Override
	protected BasicValue getElementValue(final BasicValue objectArrayValue) throws AnalyzerException {
	Type arrayType = objectArrayValue.getType();
	if (arrayType != null) {
	if (arrayType.getSort() == Type.ARRAY) {
	return newValue(Type.getType(arrayType.getDescriptor().substring(1)));
	} else if (arrayType.equals(NULL_TYPE)) {
	return objectArrayValue;
	}
	}
	throw new AssertionError();
	}

	@Override
	protected boolean isSubTypeOf(final BasicValue value, final BasicValue expected) {
	Type expectedType = expected.getType();
	Type type = value.getType();
	switch (expectedType.getSort()) {
	case Type.INT:
	case Type.FLOAT:
	case Type.LONG:
	case Type.DOUBLE:
	return type.equals(expectedType);
	case Type.ARRAY:
	case Type.OBJECT:
	if (type.equals(NULL_TYPE)) {
	return true;
	} else if (type.getSort() == Type.OBJECT \|\| type.getSort() == Type.ARRAY) {
	if (isAssignableFrom(expectedType, type)) {
	return true;
	} else if (getClass(expectedType).isInterface()) {
	// The merge of class or interface types can only yield class types (because it is not
	// possible in general to find an unambiguous common super interface, due to multiple
	// inheritance). Because of this limitation, we need to relax the subtyping check here
	// if 'value' is an interface.
	return Object.class.isAssignableFrom(getClass(type));
	} else {
	return false;
	}
	} else {
	return false;
	}
	default:
	throw new AssertionError();
	}
	}

	@Override
	public BasicValue merge(final BasicValue value1, final BasicValue value2) {
	if (!value1.equals(value2)) {
	Type type1 = value1.getType();
	Type type2 = value2.getType();
	if (type1 != null
	&& (type1.getSort() == Type.OBJECT \|\| type1.getSort() == Type.ARRAY)
	&& type2 != null
	&& (type2.getSort() == Type.OBJECT \|\| type2.getSort() == Type.ARRAY)) {
	if (type1.equals(NULL_TYPE)) {
	return value2;
	}
	if (type2.equals(NULL_TYPE)) {
	return value1;
	}
	if (isAssignableFrom(type1, type2)) {
	return value1;
	}
	if (isAssignableFrom(type2, type1)) {
	return value2;
	}
	int numDimensions = 0;
	if (type1.getSort() == Type.ARRAY
	&& type2.getSort() == Type.ARRAY
	&& type1.getDimensions() == type2.getDimensions()
	&& type1.getElementType().getSort() == Type.OBJECT
	&& type2.getElementType().getSort() == Type.OBJECT) {
	numDimensions = type1.getDimensions();
	type1 = type1.getElementType();
	type2 = type2.getElementType();
	}
	while (true) {
	if (type1 == null \|\| isInterface(type1)) {
	return newArrayValue(Type.getObjectType("java/lang/Object"), numDimensions);
	}
	type1 = getSuperClass(type1);
	if (isAssignableFrom(type1, type2)) {
	return newArrayValue(type1, numDimensions);
	}
	}
	}
	return BasicValue.UNINITIALIZED_VALUE;
	}
	return value1;
	}

	private BasicValue newArrayValue(final Type type, final int dimensions) {
	if (dimensions == 0) {
	return newValue(type);
	} else {
	StringBuilder descriptor = new StringBuilder();
	for (int i = 0; i < dimensions; ++i) {
	descriptor.append('[');
	}
	descriptor.append(type.getDescriptor());
	return newValue(Type.getType(descriptor.toString()));
	}
	}

	/**
	* Returns whether the given type corresponds to the type of an interface. The default
	* implementation of this method loads the class and uses the reflection API to return its result
	* (unless the given type corresponds to the class being verified).
	*
	* @param type a type.
	* @return whether 'type' corresponds to an interface.
	*/
	protected boolean isInterface(final Type type) {
	if (currentClass != null && currentClass.equals(type)) {
	return isInterface;
	}
	return getClass(type).isInterface();
	}

	/**
	* Returns the type corresponding to the super class of the given type. The default implementation
	* of this method loads the class and uses the reflection API to return its result (unless the
	* given type corresponds to the class being verified).
	*
	* @param type a type.
	* @return the type corresponding to the super class of 'type'.
	*/
	protected Type getSuperClass(final Type type) {
	if (currentClass != null && currentClass.equals(type)) {
	return currentSuperClass;
	}
	Class<?> superClass = getClass(type).getSuperclass();
	return superClass == null ? null : Type.getType(superClass);
	}

	/**
	* Returns whether the class corresponding to the first argument is either the same as, or is a
	* superclass or superinterface of the class corresponding to the second argument. The default
	* implementation of this method loads the classes and uses the reflection API to return its
	* result (unless the result can be computed from the class being verified, and the types of its
	* super classes and implemented interfaces).
	*
	* @param type1 a type.
	* @param type2 another type.
	* @return whether the class corresponding to 'type1' is either the same as, or is a superclass or
	* superinterface of the class corresponding to 'type2'.
	*/
	protected boolean isAssignableFrom(final Type type1, final Type type2) {
	if (type1.equals(type2)) {
	return true;
	}
	if (currentClass != null && currentClass.equals(type1)) {
	if (getSuperClass(type2) == null) {
	return false;
	} else {
	if (isInterface) {
	return type2.getSort() == Type.OBJECT \|\| type2.getSort() == Type.ARRAY;
	}
	return isAssignableFrom(type1, getSuperClass(type2));
	}
	}
	if (currentClass != null && currentClass.equals(type2)) {
	if (isAssignableFrom(type1, currentSuperClass)) {
	return true;
	}
	if (currentClassInterfaces != null) {
	for (Type currentClassInterface : currentClassInterfaces) {
	if (isAssignableFrom(type1, currentClassInterface)) {
	return true;
	}
	}
	}
	return false;
	}
	return getClass(type1).isAssignableFrom(getClass(type2));
	}

	/**
	* Loads the class corresponding to the given type. The class is loaded with the class loader
	* specified with {@link #setClassLoader}, or with the class loader of this class if no class
	* loader was specified.
	*
	* @param type a type.
	* @return the class corresponding to 'type'.
	*/
	protected Class<?> getClass(final Type type) {
	try {
	if (type.getSort() == Type.ARRAY) {
	return Class.forName(type.getDescriptor().replace('/', '.'), false, loader);
	}
	return Class.forName(type.getClassName(), false, loader);
	} catch (ClassNotFoundException e) {
	throw new TypeNotPresentException(e.toString(), e);
	}
	}
	}

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