proguard.optimize.info.SideEffectClassChecker 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.optimize.info;
import proguard.classfile.*;
import proguard.classfile.visitor.ClassCollector;
import java.util.*;
/**
* This utility class contains methods to check whether referencing classes
* may have side effects due to them being loaded and initialized.
*
* @see NoSideEffectClassMarker
* @see SideEffectClassMarker
* @author Eric Lafortune
*/
public class SideEffectClassChecker
{
/**
* Returns whether accessing the given class member from the given class may
* have side effects when they are initialized.
*/
public static boolean mayHaveSideEffects(Clazz referencingClass,
Clazz referencedClass,
Member referencedMember)
{
// Is the referenced class member static or an initializer method?
// Does accessing the referenced class then have side effects?
return
((referencedMember.getAccessFlags() & ClassConstants.ACC_STATIC) != 0 ||
referencedMember.getName(referencedClass).equals(ClassConstants.METHOD_NAME_INIT)) &&
mayHaveSideEffects(referencingClass, referencedClass);
}
/**
* Returns whether accessing the given class from another given class may
* have side effects when they are initialized.
*/
public static boolean mayHaveSideEffects(Clazz referencingClass,
Clazz referencedClass)
{
return
!NoSideEffectClassMarker.hasNoSideEffects(referencedClass) &&
!referencingClass.extendsOrImplements(referencedClass) &&
!sideEffectSuperClasses(referencingClass).containsAll(sideEffectSuperClasses(referencedClass));
}
/**
* Returns the set of superclasses and interfaces that are initialized.
*/
private static Set sideEffectSuperClasses(Clazz clazz)
{
Set set = new HashSet();
// Visit all superclasses and interfaces, collecting the ones that have
// side effects when they are initialized.
clazz.hierarchyAccept(true, true, true, false,
new SideEffectClassFilter(
new ClassCollector(set)));
return set;
}
}
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