proguard.shrink.InnerUsageMarker Maven / Gradle / Ivy
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2018 GuardSquare NV
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.shrink;
import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.ClassVisitor;
/**
* This AttributeVisitor recursively marks all necessary inner class information
* in the attributes that it visits.
*
* @see UsageMarker
*
* @author Eric Lafortune
*/
public class InnerUsageMarker
extends SimplifiedVisitor
implements AttributeVisitor,
InnerClassesInfoVisitor,
ConstantVisitor,
ClassVisitor
{
private final UsageMarker usageMarker;
// Fields acting as a return parameters for several methods.
private boolean attributeUsed;
private boolean classUsed;
/**
* Creates a new InnerUsageMarker.
* @param usageMarker the usage marker that is used to mark the classes
* and class members.
*/
public InnerUsageMarker(UsageMarker usageMarker)
{
this.usageMarker = usageMarker;
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitInnerClassesAttribute(Clazz clazz, InnerClassesAttribute innerClassesAttribute)
{
// Mark the necessary inner classes information.
attributeUsed = false;
innerClassesAttribute.innerClassEntriesAccept(clazz, this);
if (attributeUsed)
{
// We got a positive used flag, so some inner class is being used.
// Mark this attribute as being used as well.
usageMarker.markAsUsed(innerClassesAttribute);
markConstant(clazz, innerClassesAttribute.u2attributeNameIndex);
}
}
// Implementations for InnerClassesInfoVisitor.
public void visitInnerClassesInfo(Clazz clazz, InnerClassesInfo innerClassesInfo)
{
boolean innerClassesInfoUsed = usageMarker.isUsed(innerClassesInfo);
if (!innerClassesInfoUsed)
{
// Check if the inner class (if any) is marked as being used.
classUsed = true;
innerClassesInfo.innerClassConstantAccept(clazz, this);
innerClassesInfoUsed = classUsed;
// Check if the outer class (if any) is marked as being used.
classUsed = true;
innerClassesInfo.outerClassConstantAccept(clazz, this);
innerClassesInfoUsed &= classUsed;
// If both the inner class and the outer class are marked as being
// used, then mark this InnerClassesInfo as well.
if (innerClassesInfoUsed)
{
usageMarker.markAsUsed(innerClassesInfo);
innerClassesInfo.innerNameConstantAccept(clazz, this);
}
}
// The return value.
attributeUsed |= innerClassesInfoUsed;
}
// Implementations for ConstantVisitor.
public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
{
classUsed = usageMarker.isUsed(classConstant);
// Is the class constant marked as being used?
if (!classUsed)
{
// Check the referenced class.
classUsed = true;
classConstant.referencedClassAccept(this);
// Is the referenced class marked as being used?
if (classUsed)
{
// Mark the class constant and its Utf8 constant.
usageMarker.markAsUsed(classConstant);
markConstant(clazz, classConstant.u2nameIndex);
}
}
}
public void visitUtf8Constant(Clazz clazz, Utf8Constant utf8Constant)
{
usageMarker.markAsUsed(utf8Constant);
}
// Implementations for ClassVisitor.
public void visitProgramClass(ProgramClass programClass)
{
classUsed = usageMarker.isUsed(programClass);
}
public void visitLibraryClass(LibraryClass libraryClass)
{
classUsed = true;
}
// Small utility methods.
/**
* Marks the given constant pool entry of the given class. This includes
* visiting any other referenced constant pool entries.
*/
private void markConstant(Clazz clazz, int index)
{
clazz.constantPoolEntryAccept(index, this);
}
}
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