/*
* Copyright 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.dev.jjs;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.dev.jjs.ast.Context;
import com.google.gwt.dev.jjs.ast.JClassType;
import com.google.gwt.dev.jjs.ast.JDeclaredType;
import com.google.gwt.dev.jjs.ast.JMethod;
import com.google.gwt.dev.jjs.ast.JMethodCall;
import com.google.gwt.dev.jjs.ast.JModVisitor;
import com.google.gwt.dev.jjs.ast.JParameter;
import com.google.gwt.dev.jjs.ast.JProgram;
import com.google.gwt.dev.jjs.ast.JReturnStatement;
import com.google.gwt.dev.jjs.ast.JThisRef;
import java.util.List;
/**
* Performs optimizations on Enums.
*/
public class EnumNameObfuscator {
private static class EnumNameCallChecker extends JModVisitor {
private final TreeLogger logger;
private final JMethod enumNameMethod;
private final JMethod enumToStringMethod;
private final JMethod enumValueOfMethod;
private final JDeclaredType classType;
private final JDeclaredType enumType;
private final JDeclaredType stringType;
public EnumNameCallChecker(JProgram jprogram, TreeLogger logger) {
this.logger = logger;
this.enumNameMethod = jprogram.getIndexedMethod("Enum.name");
this.enumToStringMethod = jprogram.getIndexedMethod("Enum.toString");
this.classType = jprogram.getIndexedType("Class");
this.enumType = jprogram.getIndexedType("Enum");
this.stringType = jprogram.getIndexedType("String");
/*
* Find the correct version of enumValueOfMethod.
* Note: it doesn't work to check against a ref returned by
* jprogram.getIndexedMethod("Enum.valueOf"), since there are
* 2 different versions of Enum.valueOf in our jre emulation library,
* and the indexed ref won't reliably flag the public instance, which
* is the one we want here (i.e. Enum.valueOf(Class<T>,String)).
* The other version is protected, but is called by the generated
* constructors for sub-classes of Enum, and we don't want to warn for
* those cases.
*/
JMethod foundMethod = null;
List<JMethod> enumMethods = enumType.getMethods();
for (JMethod enumMethod : enumMethods) {
if ("valueOf".equals(enumMethod.getName())) {
List<JParameter> jParameters = enumMethod.getParams();
if (jParameters.size() == 2 &&
jParameters.get(0).getType() == classType &&
jParameters.get(1).getType() == stringType) {
foundMethod = enumMethod;
break;
}
}
}
this.enumValueOfMethod = foundMethod;
}
@Override
public void endVisit(JMethodCall x, Context ctx) {
JMethod target = x.getTarget();
JDeclaredType type = target.getEnclosingType();
if (type instanceof JClassType) {
JClassType cType = (JClassType) type;
if (target == enumNameMethod ||
target == enumToStringMethod ||
target == enumValueOfMethod) {
warn(x);
} else if (cType.isEnumOrSubclass() != null) {
if ("valueOf".equals(target.getName())) {
/*
* Check for calls to the auto-generated EnumSubType.valueOf(String).
* Note, the check of the signature for the single String arg version
* is to avoid flagging user-defined overloaded versions of the
* method, which are presumably ok.
*/
List<JParameter> jParameters = target.getParams();
if (jParameters.size() == 1 &&
jParameters.get(0).getType() == stringType) {
warn(x);
}
}
}
}
}
@Override
public boolean visit(JClassType x, Context ctx) {
if (x == enumType) {
// don't traverse into Enum class itself, don't warn on internal method calls
return false;
}
return true;
}
private void warn(JMethodCall x) {
/* TODO: add a way to suppress warning with annotation if you know what
* you're doing.
*/
logger.log(TreeLogger.WARN, "Call to Enum method "
+ x.getTarget().getName() + " when enum obfuscation is enabled: "
+ x.getSourceInfo().getFileName() + ":"
+ x.getSourceInfo().getStartLine());
}
}
private static class EnumNameReplacer extends JModVisitor {
private final TreeLogger logger;
private final JProgram jprogram;
private final JMethod enumObfuscatedName;
private final JClassType enumType;
public EnumNameReplacer(JProgram jprogram, TreeLogger logger) {
this.logger = logger;
this.jprogram = jprogram;
this.enumType = (JClassType) jprogram.getIndexedType("Enum");
this.enumObfuscatedName = jprogram.getIndexedMethod("Enum.obfuscatedName");
}
@Override
public void endVisit(JReturnStatement x, Context ctx) {
info(x);
JReturnStatement toReturn = new JReturnStatement(x.getSourceInfo(),
new JMethodCall(x.getSourceInfo(),
new JThisRef(x.getSourceInfo(),enumType), enumObfuscatedName));
ctx.replaceMe(toReturn);
}
public void exec() {
accept(jprogram.getIndexedMethod("Enum.name"));
}
private void info(JReturnStatement x) {
logger.log(TreeLogger.INFO, "Replacing Enum.name method : "
+ x.getSourceInfo().getFileName() + ":"
+ x.getSourceInfo().getStartLine());
}
}
public static void exec(JProgram jprogram, TreeLogger logger) {
new EnumNameCallChecker(jprogram, logger).accept(jprogram);
new EnumNameReplacer(jprogram, logger).exec();
}
}