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/*******************************************************************************
* Copyright (c) 2015 Jeff Martin.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the GNU Lesser General Public
* License v3.0 which accompanies this distribution, and is available at
* http://www.gnu.org/licenses/lgpl.html
* <p>
* Contributors:
* Jeff Martin - initial API and implementation
******************************************************************************/
package cuchaz.enigma.bytecode;
import cuchaz.enigma.mapping.*;
import javassist.CtBehavior;
import javassist.CtClass;
import javassist.bytecode.*;
public class LocalVariableRenamer {
private Translator translator;
public LocalVariableRenamer(Translator translator) {
this.translator = translator;
}
public void rename(CtClass c) {
for (CtBehavior behavior : c.getDeclaredBehaviors()) {
// if there's a local variable table, just rename everything to v1, v2, v3, ... for now
CodeAttribute codeAttribute = behavior.getMethodInfo().getCodeAttribute();
if (codeAttribute == null) {
continue;
}
BehaviorEntry behaviorEntry = EntryFactory.getBehaviorEntry(behavior);
ConstPool constants = c.getClassFile().getConstPool();
LocalVariableAttribute table = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
if (table != null) {
renameLVT(behaviorEntry, constants, table);
}
LocalVariableTypeAttribute typeTable = (LocalVariableTypeAttribute) codeAttribute.getAttribute(LocalVariableAttribute.typeTag);
if (typeTable != null) {
renameLVTT(typeTable, table);
}
}
}
// DEBUG
@SuppressWarnings("unused")
private void dumpTable(LocalVariableAttribute table) {
for (int i = 0; i < table.tableLength(); i++) {
System.out.println(String.format("\t%d (%d): %s %s",
i, table.index(i), table.variableName(i), table.descriptor(i)
));
}
}
private void renameLVT(BehaviorEntry behaviorEntry, ConstPool constants, LocalVariableAttribute table) {
// skip empty tables
if (table.tableLength() <= 0) {
return;
}
// where do we start counting variables?
int starti = 0;
if (table.variableName(0).equals("this")) {
// skip the "this" variable
starti = 1;
}
// rename method arguments first
int numArgs = 0;
if (behaviorEntry.getSignature() != null) {
numArgs = behaviorEntry.getSignature().getArgumentTypes().size();
boolean isNestedClassConstructor = false;
// If the behavior is a constructor and if it have more than one arg, it's probably from a nested!
if (behaviorEntry instanceof ConstructorEntry && behaviorEntry.getClassEntry() != null && behaviorEntry.getClassEntry().isInnerClass() && numArgs >= 1) {
// Get the first arg type
Type firstArg = behaviorEntry.getSignature().getArgumentTypes().get(0);
// If the arg is a class and if the class name match the outer class name of the constructor, it's definitely a constructor of a nested class
if (firstArg.isClass() && firstArg.getClassEntry().equals(behaviorEntry.getClassEntry().getOuterClassEntry())) {
isNestedClassConstructor = true;
numArgs--;
}
}
for (int i = starti; i < starti + numArgs && i < table.tableLength(); i++) {
int argi = i - starti;
String argName = this.translator.translate(new ArgumentEntry(behaviorEntry, argi, ""));
if (argName == null) {
Type argType = behaviorEntry.getSignature().getArgumentTypes().get(isNestedClassConstructor ? argi + 1 : argi);
// Unfortunately each of these have different name getters, so they have different code paths
if (argType.isPrimitive()) {
Type.Primitive argCls = argType.getPrimitive();
argName = "a" + argCls.name() + (argi + 1);
} else if (argType.isArray()) {
// List types would require this whole block again, so just go with aListx
argName = "aList" + (argi + 1);
} else if (argType.isClass()) {
ClassEntry argClsTrans = this.translator.translateEntry(argType.getClassEntry());
argName = "a" + argClsTrans.getSimpleName().replace("$", "") + (argi + 1);
} else {
argName = "a" + (argi + 1);
}
}
renameVariable(table, i, constants.addUtf8Info(argName));
}
}
// then rename the rest of the args, if any
for (int i = starti + numArgs; i < table.tableLength(); i++) {
int firstIndex = table.index(starti + numArgs);
renameVariable(table, i, constants.addUtf8Info("v" + (table.index(i) - firstIndex + 1)));
}
}
private void renameLVTT(LocalVariableTypeAttribute typeTable, LocalVariableAttribute table) {
// rename args to the same names as in the LVT
for (int i = 0; i < typeTable.tableLength(); i++) {
renameVariable(typeTable, i, getNameIndex(table, typeTable.index(i)));
}
}
private void renameVariable(LocalVariableAttribute table, int i, int stringId) {
// based off of LocalVariableAttribute.nameIndex()
ByteArray.write16bit(stringId, table.get(), i * 10 + 6);
}
private int getNameIndex(LocalVariableAttribute table, int index) {
for (int i = 0; i < table.tableLength(); i++) {
if (table.index(i) == index) {
return table.nameIndex(i);
}
}
return 0;
}
}
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