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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2013 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.visitor.*;
/**
* This ClassVisitor and MemberVisitor recursively marks all classes
* and class elements that are being used. For each element, it finds the
* shortest chain of dependencies.
*
* @see ClassShrinker
*
* @author Eric Lafortune
*/
public class ShortestUsageMarker extends UsageMarker
{
private static final ShortestUsageMark INITIAL_MARK =
new ShortestUsageMark("is kept by a directive in the configuration.\n\n");
// A field acting as a parameter to the visitor methods.
private ShortestUsageMark currentUsageMark = INITIAL_MARK;
// A utility object to check for recursive causes.
private final MyRecursiveCauseChecker recursiveCauseChecker = new MyRecursiveCauseChecker();
// Overriding implementations for UsageMarker.
protected void markProgramClassBody(ProgramClass programClass)
{
ShortestUsageMark previousUsageMark = currentUsageMark;
currentUsageMark = new ShortestUsageMark(getShortestUsageMark(programClass),
"is extended by ",
10000,
programClass);
super.markProgramClassBody(programClass);
currentUsageMark = previousUsageMark;
}
protected void markProgramFieldBody(ProgramClass programClass, ProgramField programField)
{
ShortestUsageMark previousUsageMark = currentUsageMark;
currentUsageMark = new ShortestUsageMark(getShortestUsageMark(programField),
"is referenced by ",
1,
programClass,
programField);
super.markProgramFieldBody(programClass, programField);
currentUsageMark = previousUsageMark;
}
protected void markProgramMethodBody(ProgramClass programClass, ProgramMethod programMethod)
{
ShortestUsageMark previousUsageMark = currentUsageMark;
currentUsageMark = new ShortestUsageMark(getShortestUsageMark(programMethod),
"is invoked by ",
1,
programClass,
programMethod);
super.markProgramMethodBody(programClass, programMethod);
currentUsageMark = previousUsageMark;
}
protected void markMethodHierarchy(Clazz clazz, Method method)
{
ShortestUsageMark previousUsageMark = currentUsageMark;
currentUsageMark = new ShortestUsageMark(getShortestUsageMark(method),
"implements ",
100,
clazz,
method);
super.markMethodHierarchy(clazz, method);
currentUsageMark = previousUsageMark;
}
// Small utility methods.
protected void markAsUsed(VisitorAccepter visitorAccepter)
{
Object visitorInfo = visitorAccepter.getVisitorInfo();
ShortestUsageMark shortestUsageMark =
visitorInfo != null &&
visitorInfo instanceof ShortestUsageMark &&
!((ShortestUsageMark)visitorInfo).isCertain() &&
!currentUsageMark.isShorter((ShortestUsageMark)visitorInfo) ?
new ShortestUsageMark((ShortestUsageMark)visitorInfo, true):
currentUsageMark;
visitorAccepter.setVisitorInfo(shortestUsageMark);
}
protected boolean shouldBeMarkedAsUsed(VisitorAccepter visitorAccepter)
{
Object visitorInfo = visitorAccepter.getVisitorInfo();
return //!(visitorAccepter instanceof Clazz &&
// isCausedBy(currentUsageMark, (Clazz)visitorAccepter)) &&
(visitorInfo == null ||
!(visitorInfo instanceof ShortestUsageMark) ||
!((ShortestUsageMark)visitorInfo).isCertain() ||
currentUsageMark.isShorter((ShortestUsageMark)visitorInfo));
}
protected boolean isUsed(VisitorAccepter visitorAccepter)
{
Object visitorInfo = visitorAccepter.getVisitorInfo();
return visitorInfo != null &&
visitorInfo instanceof ShortestUsageMark &&
((ShortestUsageMark)visitorInfo).isCertain();
}
protected void markAsPossiblyUsed(VisitorAccepter visitorAccepter)
{
visitorAccepter.setVisitorInfo(new ShortestUsageMark(currentUsageMark, false));
}
protected boolean shouldBeMarkedAsPossiblyUsed(VisitorAccepter visitorAccepter)
{
Object visitorInfo = visitorAccepter.getVisitorInfo();
return visitorInfo == null ||
!(visitorInfo instanceof ShortestUsageMark) ||
(!((ShortestUsageMark)visitorInfo).isCertain() &&
currentUsageMark.isShorter((ShortestUsageMark)visitorInfo));
}
protected boolean isPossiblyUsed(VisitorAccepter visitorAccepter)
{
Object visitorInfo = visitorAccepter.getVisitorInfo();
return visitorInfo != null &&
visitorInfo instanceof ShortestUsageMark &&
!((ShortestUsageMark)visitorInfo).isCertain();
}
protected ShortestUsageMark getShortestUsageMark(VisitorAccepter visitorAccepter)
{
Object visitorInfo = visitorAccepter.getVisitorInfo();
return (ShortestUsageMark)visitorInfo;
}
// Small utility methods.
private boolean isCausedBy(ShortestUsageMark shortestUsageMark,
Clazz clazz)
{
return recursiveCauseChecker.check(shortestUsageMark, clazz);
}
private class MyRecursiveCauseChecker implements ClassVisitor, MemberVisitor
{
private Clazz checkClass;
private boolean isRecursing;
public boolean check(ShortestUsageMark shortestUsageMark,
Clazz clazz)
{
checkClass = clazz;
isRecursing = false;
shortestUsageMark.acceptClassVisitor(this);
shortestUsageMark.acceptMemberVisitor(this);
return isRecursing;
}
// Implementations for ClassVisitor.
public void visitProgramClass(ProgramClass programClass)
{
checkCause(programClass);
}
public void visitLibraryClass(LibraryClass libraryClass)
{
checkCause(libraryClass);
}
// Implementations for MemberVisitor.
public void visitProgramField(ProgramClass programClass, ProgramField programField)
{
checkCause(programField);
}
public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
{
checkCause(programMethod);
}
public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)
{
checkCause(libraryField);
}
public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)
{
checkCause(libraryMethod);
}
// Small utility methods.
private void checkCause(VisitorAccepter visitorAccepter)
{
if (ShortestUsageMarker.this.isUsed(visitorAccepter))
{
ShortestUsageMark shortestUsageMark = ShortestUsageMarker.this.getShortestUsageMark(visitorAccepter);
// Check the class of this mark, if any
isRecursing = shortestUsageMark.isCausedBy(checkClass);
// Check the causing class or method, if still necessary.
if (!isRecursing)
{
shortestUsageMark.acceptClassVisitor(this);
shortestUsageMark.acceptMemberVisitor(this);
}
}
}
}
}
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