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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
/*
* ProGuardCORE -- library to process Java bytecode.
*
* Copyright (c) 2002-2020 Guardsquare NV
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package proguard.classfile.util;
import proguard.classfile.*;
import proguard.classfile.visitor.*;
/**
* This utility class provides methods to find class members in a given class
* or in its hierarchy.
*
* @author Eric Lafortune
*/
public class MemberFinder
implements MemberVisitor
{
private static class MemberFoundException extends RuntimeException {}
private static final MemberFoundException MEMBER_FOUND = new MemberFoundException();
private final boolean searchHierarchy;
private Clazz clazz;
private Member member;
/**
* Creates a new MemberFinder that looks in the class hierarchy.
*/
public MemberFinder()
{
this(true);
}
/**
* Creates a new MemberFinder that looks in the class hierarchy if
* specified.
*/
public MemberFinder(boolean searchHierarchy)
{
this.searchHierarchy = searchHierarchy;
}
/**
* Finds the field with the given name and descriptor in the given
* class or its hierarchy. The name and descriptor may contain wildcards.
*/
public Field findField(Clazz clazz,
String name,
String descriptor)
{
return findField(null, clazz, name, descriptor);
}
/**
* Finds the field with the given name and descriptor in the given
* class or its hierarchy. The name and descriptor may contain wildcards.
*/
public Field findField(Clazz referencingClass,
Clazz clazz,
String name,
String descriptor)
{
return (Field)findMember(referencingClass, clazz, name, descriptor, true);
}
/**
* Finds the method with the given name and descriptor in the given
* class or its hierarchy. The name and descriptor may contain wildcards.
*/
public Method findMethod(Clazz clazz,
String name,
String descriptor)
{
return findMethod(null, clazz, name, descriptor);
}
/**
* Finds the method with the given name and descriptor in the given
* class or its hierarchy. The name and descriptor may contain wildcards.
*/
public Method findMethod(Clazz referencingClass,
Clazz clazz,
String name,
String descriptor)
{
return (Method)findMember(referencingClass, clazz, name, descriptor, false);
}
/**
* Finds the class member with the given name and descriptor in the given
* class or its hierarchy. The name and descriptor may contain wildcards.
*/
public Member findMember(Clazz clazz,
String name,
String descriptor,
boolean isField)
{
return findMember(null, clazz, name, descriptor, isField);
}
/**
* Finds the class member with the given name and descriptor in the given
* class or its hierarchy, referenced from the optional given class.
* The name and descriptor may contain wildcards.
*/
public Member findMember(Clazz referencingClass,
Clazz clazz,
String name,
String descriptor,
boolean isField)
{
try
{
boolean containsWildcards =
(name != null && (name.indexOf('*') >= 0 || name.indexOf('?') >= 0)) ||
(descriptor != null && (descriptor.indexOf('*') >= 0 || descriptor.indexOf('?') >= 0));
this.clazz = null;
this.member = null;
// The class member may be in a different class, as of Java 1.2.
// The class member may be private in a nest member, as of Java 11.
// Check the accessibility from the referencing class, if any
// (non-dummy), taking into account access flags and nests.
MemberVisitor memberVisitor =
referencingClass != null &&
referencingClass.getName() != null ?
new MemberClassAccessFilter(referencingClass, this) :
this;
// We'll return with a MemberFoundException as soon as we've found
// the class member.
clazz.hierarchyAccept(true,
searchHierarchy,
searchHierarchy,
false,
containsWildcards ?
isField ?
new AllFieldVisitor(
new MemberNameFilter(name,
new MemberDescriptorFilter(descriptor,
memberVisitor))) :
new AllMethodVisitor(
new MemberNameFilter(name,
new MemberDescriptorFilter(descriptor,
memberVisitor))) :
isField ?
new NamedFieldVisitor(name, descriptor,
memberVisitor) :
new NamedMethodVisitor(name, descriptor,
memberVisitor));
}
catch (MemberFoundException ex)
{
// We've found the member we were looking for.
}
return member;
}
/**
* Returns the corresponding class of the most recently found class
* member.
*/
public Clazz correspondingClass()
{
return clazz;
}
/**
* Returns whether the given method is overridden anywhere down the class
* hierarchy.
*/
public boolean isOverriden(Clazz clazz,
Method method)
{
String name = method.getName(clazz);
String descriptor = method.getDescriptor(clazz);
// Go looking for the method down the class hierarchy.
try
{
this.clazz = null;
this.member = null;
clazz.hierarchyAccept(false, false, false, true,
new NamedMethodVisitor(name, descriptor,
new MemberAccessFilter(0, AccessConstants.PRIVATE, this)));
}
catch (MemberFoundException ex)
{
// We've found an overriding method.
return true;
}
return false;
}
/**
* Returns whether the given field is shadowed anywhere down the class
* hierarchy.
*/
public boolean isShadowed(Clazz clazz,
Field field)
{
String name = field.getName(clazz);
String descriptor = field.getDescriptor(clazz);
// Go looking for the field down the class hierarchy.
try
{
this.clazz = null;
this.member = null;
clazz.hierarchyAccept(false, false, false, true,
new NamedFieldVisitor(name, descriptor,
new MemberAccessFilter(0, AccessConstants.PRIVATE, this)));
}
catch (MemberFoundException ex)
{
// We've found a shadowing field.
return true;
}
return false;
}
// // Implementations for ClassVisitor.
//
// private void visitAnyClass(Clazz clazz)
// {
// if (member == null)
// {
// member = isField ?
// (Member)clazz.findField(name, descriptor) :
// (Member)clazz.findMethod(name, descriptor);
//
// if (member != null)
// {
// this.clazz = clazz;
// }
// }
// }
// Implementations for MemberVisitor.
public void visitAnyMember(Clazz clazz, Member member)
{
this.clazz = clazz;
this.member = member;
throw MEMBER_FOUND;
}
}
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