/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2004-2006 University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.detect;
import java.util.HashSet;
import org.apache.bcel.classfile.Code;
import edu.umd.cs.findbugs.BugAccumulator;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.OpcodeStack;
import edu.umd.cs.findbugs.bcel.OpcodeStackDetector;
import edu.umd.cs.findbugs.visitclass.PreorderVisitor;
/**
* We found a problem with the new OpenJDK that everyone is now using to compile
* and run java code. In particular, the java.util.logging.Logger behavior has
* changed. Instead of using strong references, it now uses weak references
* internally. That's a reasonable change, but unfortunately some code relies on
* the old behavior - when changing logger configuration, it simply drops the
* logger reference. That means that the garbage collector is free to reclaim
* that memory, which means that the logger configuration is lost.
*/
public class LostLoggerDueToWeakReference extends OpcodeStackDetector {
// final BugReporter bugReporter;
final BugAccumulator bugAccumulator;
final HashSet<String> namesOfSetterMethods = new HashSet<String>();
public LostLoggerDueToWeakReference(BugReporter bugReporter) {
// this.bugReporter = bugReporter;
this.bugAccumulator = new BugAccumulator(bugReporter);
namesOfSetterMethods.add("addHandler");
namesOfSetterMethods.add("setUseParentHandlers");
namesOfSetterMethods.add("setLevel");
namesOfSetterMethods.add("setFilter");
}
@Override
public void visit(Code code) {
if (getMethodSig().indexOf("Logger") == -1) {
sawGetLogger = -1;
loggerEscaped = loggerImported = false;
super.visit(code); // make callbacks to sawOpcode for all opcodes
/*
if (false) {
System.out.println(getFullyQualifiedMethodName());
System.out.printf("%d %s %s\n", sawGetLogger, loggerEscaped, loggerImported);
}
*/
if (sawGetLogger >= 0 && !loggerEscaped && !loggerImported) {
bugAccumulator.reportAccumulatedBugs();
} else {
bugAccumulator.clearBugs();
}
}
}
int sawGetLogger;
boolean loggerEscaped;
boolean loggerImported;
@Override
public void sawOpcode(int seen) {
if (loggerEscaped || loggerImported) {
return;
}
switch (seen) {
case INVOKESTATIC:
if (getClassConstantOperand().equals("java/util/logging/Logger") && getNameConstantOperand().equals("getLogger")) {
OpcodeStack.Item item = stack.getStackItem(0);
if (!"".equals(item.getConstant())) {
sawGetLogger = getPC();
}
break;
}
checkForImport();
break;
case INVOKEVIRTUAL:
if (getClassConstantOperand().equals("java/util/logging/Logger")
&& namesOfSetterMethods.contains(getNameConstantOperand())) {
int priority = HIGH_PRIORITY;
if (getMethod().isStatic() && getMethodName().equals("main") && getMethodSig().equals("([Ljava/lang/String;)V")) {
priority = NORMAL_PRIORITY;
}
OpcodeStack.Item item = stack.getItemMethodInvokedOn(this);
BugInstance bug = new BugInstance(this, "LG_LOST_LOGGER_DUE_TO_WEAK_REFERENCE", priority)
.addClassAndMethod(this).addValueSource(item, this);
bugAccumulator.accumulateBug(bug, this);
break;
}
checkForImport();
checkForMethodExportImport();
break;
case INVOKEINTERFACE:
case INVOKESPECIAL:
checkForImport();
checkForMethodExportImport();
break;
case CHECKCAST:
String sig = getClassConstantOperand();
if (sig.indexOf("Logger") >= 0) {
loggerImported = true;
}
break;
case GETFIELD:
case GETSTATIC:
checkForImport();
break;
case PUTFIELD:
case PUTSTATIC:
checkForFieldEscape();
break;
default:
break;
}
}
private void checkForImport() {
if (getSigConstantOperand().endsWith("Logger;")) {
loggerImported = true;
}
}
private void checkForMethodExportImport() {
int numArguments = PreorderVisitor.getNumberArguments(getSigConstantOperand());
for (int i = 0; i < numArguments; i++) {
OpcodeStack.Item item = stack.getStackItem(i);
if (item.getSignature().endsWith("Logger;")) {
loggerEscaped = true;
}
}
String sig = getSigConstantOperand();
int pos = sig.indexOf(')');
int loggerPos = sig.indexOf("Logger");
if (0 <= loggerPos && loggerPos < pos) {
loggerEscaped = true;
}
}
private void checkForFieldEscape() {
String sig = getSigConstantOperand();
if (sig.indexOf("Logger") >= 0) {
loggerEscaped = true;
}
OpcodeStack.Item item = stack.getStackItem(0);
if (item.getSignature().endsWith("Logger;")) {
loggerEscaped = true;
}
}
}