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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.classfile.util;
import proguard.classfile.*;
import proguard.classfile.visitor.*;
import java.util.*;
/**
* This ClassVisitor links all corresponding non-private, non-static,
* non-initializer methods in the class hierarchies of all visited classes.
* Visited classes are typically all class files that are not being subclassed.
* Chains of links that have been created in previous invocations are merged
* with new chains of links, in order to create a consistent set of chains.
*
* @author Eric Lafortune
*/
public class MethodLinker
extends SimplifiedVisitor
implements ClassVisitor,
MemberVisitor
{
// An object that is reset and reused every time.
// The map: [class member name+' '+descriptor - class member info]
private final Map memberMap = new HashMap();
// Implementations for ClassVisitor.
public void visitAnyClass(Clazz clazz)
{
// Collect all non-private members in this class hierarchy.
clazz.hierarchyAccept(true, true, true, false,
new AllMethodVisitor(
new MemberAccessFilter(0, ClassConstants.ACC_PRIVATE | ClassConstants.ACC_STATIC,
this)));
// Clean up for the next class hierarchy.
memberMap.clear();
}
// Implementations for MemberVisitor.
public void visitAnyMember(Clazz clazz, Member member)
{
// Get the class member's name and descriptor.
String name = member.getName(clazz);
String descriptor = member.getDescriptor(clazz);
// Special cases: <clinit> and <init> are always kept unchanged.
// We can ignore them here.
if (ClassUtil.isInitializer(name))
{
return;
}
// See if we've already come across a method with the same name and
// descriptor.
String key = name + ' ' + descriptor;
Member otherMember = (Member)memberMap.get(key);
if (otherMember == null)
{
// Get the last method in the chain.
Member thisLastMember = lastMember(member);
// Store the new class method in the map.
memberMap.put(key, thisLastMember);
}
else
{
// Link both members.
link(member, otherMember);
}
}
// Small utility methods.
/**
* Links the two given class members.
*/
private static void link(Member member1, Member member2)
{
// Get the last methods in the both chains.
Member lastMember1 = lastMember(member1);
Member lastMember2 = lastMember(member2);
// Check if both link chains aren't already ending in the same element.
if (!lastMember1.equals(lastMember2))
{
// Merge the two chains, with the library members last.
if (lastMember2 instanceof LibraryMember)
{
lastMember1.setVisitorInfo(lastMember2);
}
else
{
lastMember2.setVisitorInfo(lastMember1);
}
}
}
/**
* Finds the last class member in the linked list of related class members.
* @param member the given class member.
* @return the last class member in the linked list.
*/
public static Member lastMember(Member member)
{
Member lastMember = member;
while (lastMember.getVisitorInfo() != null &&
lastMember.getVisitorInfo() instanceof Member)
{
lastMember = (Member)lastMember.getVisitorInfo();
}
return lastMember;
}
/**
* Finds the last visitor accepter in the linked list of visitors.
* @param visitorAccepter the given method.
* @return the last method in the linked list.
*/
public static VisitorAccepter lastVisitorAccepter(VisitorAccepter visitorAccepter)
{
VisitorAccepter lastVisitorAccepter = visitorAccepter;
while (lastVisitorAccepter.getVisitorInfo() != null &&
lastVisitorAccepter.getVisitorInfo() instanceof VisitorAccepter)
{
lastVisitorAccepter = (VisitorAccepter)lastVisitorAccepter.getVisitorInfo();
}
return lastVisitorAccepter;
}
}
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