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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2014 Eric Lafortune (eric@graphics.cornell.edu)
*
* 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.Constant;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.ClassVisitor;
/**
* This AttributeVisitor recursively marks all information that points to used
* classes, in the LocalVariableTable and LocalVariableTypeTable attributes that
* it visits.
*
* @see UsageMarker
*
* @author Eric Lafortune
*/
public class LocalVariableTypeUsageMarker
extends SimplifiedVisitor
implements AttributeVisitor,
LocalVariableInfoVisitor,
LocalVariableTypeInfoVisitor,
ClassVisitor,
ConstantVisitor
{
private final UsageMarker usageMarker;
// Fields acting as return values for several visitor methods.
private boolean tableUsed;
private boolean variableInfoUsed;
/**
* Creates a new LocalVariableTypeUsageMarker.
* @param usageMarker the usage marker that is used to mark the classes
* and class members.
*/
public LocalVariableTypeUsageMarker(UsageMarker usageMarker)
{
this.usageMarker = usageMarker;
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitLocalVariableTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTableAttribute localVariableTableAttribute)
{
// Check and mark the individual entries.
tableUsed = false;
localVariableTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this);
// Mark the table if any of the entries is marked.
if (tableUsed)
{
usageMarker.markAsUsed(localVariableTableAttribute);
markConstant(clazz, localVariableTableAttribute.u2attributeNameIndex);
}
}
public void visitLocalVariableTypeTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeTableAttribute localVariableTypeTableAttribute)
{
// Check and mark the individual entries.
tableUsed = false;
localVariableTypeTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this);
// Mark the table if any of the entries is marked.
if (tableUsed)
{
usageMarker.markAsUsed(localVariableTypeTableAttribute);
markConstant(clazz, localVariableTypeTableAttribute.u2attributeNameIndex);
}
}
// Implementations for LocalVariableInfoVisitor.
public void visitLocalVariableInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableInfo localVariableInfo)
{
// Only keep the local variable info if all of its classes are used.
variableInfoUsed = true;
localVariableInfo.referencedClassAccept(this);
if (variableInfoUsed)
{
// We got a positive used flag, so the local variable info is useful.
usageMarker.markAsUsed(localVariableInfo);
markConstant(clazz, localVariableInfo.u2nameIndex);
markConstant(clazz, localVariableInfo.u2descriptorIndex);
tableUsed = true;
}
}
// Implementations for LocalVariableTypeInfoVisitor.
public void visitLocalVariableTypeInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeInfo localVariableTypeInfo)
{
// Only keep the local variable info if all of its classes are used.
variableInfoUsed = true;
localVariableTypeInfo.referencedClassesAccept(this);
if (variableInfoUsed)
{
// We got a positive used flag, so the local variable info is useful.
usageMarker.markAsUsed(localVariableTypeInfo);
markConstant(clazz, localVariableTypeInfo.u2nameIndex);
markConstant(clazz, localVariableTypeInfo.u2signatureIndex);
tableUsed = true;
}
}
// Implementations for ClassVisitor.
public void visitLibraryClass(LibraryClass libraryClass) {}
public void visitProgramClass(ProgramClass programClass)
{
// Don't keep the local variable info if one of its classes is not used.
if (!usageMarker.isUsed(programClass))
{
variableInfoUsed = false;
}
}
// Implementations for ConstantVisitor.
public void visitAnyConstant(Clazz clazz, Constant constant)
{
usageMarker.markAsUsed(constant);
}
// Small utility methods.
/**
* Marks the given constant pool entry of the given class.
*/
private void markConstant(Clazz clazz, int index)
{
clazz.constantPoolEntryAccept(index, this);
}
}
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