/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2003,2004 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.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.JavaClass;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.SystemProperties;
public class InitializationChain extends BytecodeScanningDetector {
Set<String> requires = new TreeSet<String>();
Map<String, Set<String>> classRequires = new TreeMap<String, Set<String>>();
Set<String> staticFieldsAccessedInConstructor = new HashSet<String>();
Map<String, BugInstance> staticFieldWritten = new HashMap<String, BugInstance>();
private BugReporter bugReporter;
private boolean instanceCreated;
private int instanceCreatedPC;
private boolean instanceCreatedWarningGiven;
private static final boolean DEBUG = SystemProperties.getBoolean("ic.debug");
public InitializationChain(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public void visit(Code obj) {
instanceCreated = false;
instanceCreatedWarningGiven = false;
if (!getMethodName().equals("<clinit>") && !getMethodName().equals("<init>")) return;
super.visit(obj);
requires.remove(getDottedClassName());
if (getDottedClassName().equals("java.lang.System")) {
requires.add("java.io.FileInputStream");
requires.add("java.io.FileOutputStream");
requires.add("java.io.BufferedInputStream");
requires.add("java.io.BufferedOutputStream");
requires.add("java.io.PrintStream");
}
if (!requires.isEmpty()) {
classRequires.put(getDottedClassName(), requires);
requires = new TreeSet<String>();
}
}
@Override
public void visitAfter(JavaClass obj) {
for(String name : staticFieldsAccessedInConstructor) {
BugInstance bug = staticFieldWritten.get(name);
if (bug != null) bugReporter.reportBug(bug);
}
staticFieldWritten.clear();
staticFieldsAccessedInConstructor.clear();
}
@Override
public void sawOpcode(int seen) {
if (getMethodName().equals("<init>")) {
if (seen == GETSTATIC && getClassConstantOperand().equals(getClassName())) {
staticFieldsAccessedInConstructor.add(getNameConstantOperand());
}
return;
}
if (seen == PUTSTATIC && getClassConstantOperand().equals(getClassName())) {
// Don't do this check; it generates too many false
// positives. We need to do a more detailed check
// of which variables could be seen.
if (instanceCreated && !instanceCreatedWarningGiven && !getSuperclassName().equals("java.lang.Enum")) {
String okSig = "L" + getClassName() + ";";
if (!okSig.equals(getSigConstantOperand())) {
staticFieldWritten.put(getNameConstantOperand(),
new BugInstance(this, "SI_INSTANCE_BEFORE_FINALS_ASSIGNED", NORMAL_PRIORITY)
.addClassAndMethod(this)
.addReferencedField(this)
.addSourceLine(this, instanceCreatedPC));
instanceCreatedWarningGiven = true;
}
}
} else if (seen == NEW && getClassConstantOperand().equals(getClassName())) {
instanceCreated = true;
instanceCreatedPC = getPC();
} else if (seen == PUTSTATIC || seen == GETSTATIC || seen == INVOKESTATIC
|| seen == NEW)
if (getPC() + 6 < codeBytes.length)
requires.add(getDottedClassConstantOperand());
}
public void compute() {
Set<String> allClasses = classRequires.keySet();
Set<String> emptyClasses = new TreeSet<String>();
for (String c : allClasses) {
Set<String> needs = classRequires.get(c);
needs.retainAll(allClasses);
Set<String> extra = new TreeSet<String>();
for (String need : needs)
extra.addAll(classRequires.get(need));
needs.addAll(extra);
needs.retainAll(allClasses);
classRequires.put(c, needs);
if (needs.isEmpty()) emptyClasses.add(c);
}
for (String c : emptyClasses) {
classRequires.remove(c);
}
}
@Override
public void report() {
if (DEBUG) System.out.println("Finishing computation");
compute();
compute();
compute();
compute();
compute();
compute();
compute();
compute();
Set<String> allClasses = classRequires.keySet();
for (String c : allClasses) {
if (DEBUG) System.out.println("Class " + c + " requires:");
for (String needs : (classRequires.get(c))) {
if (DEBUG) System.out.println(" " + needs);
Set<String> s = classRequires.get(needs);
if (s != null && s.contains(c) && c.compareTo(needs) < 0)
bugReporter.reportBug(new BugInstance(this, "IC_INIT_CIRCULARITY", NORMAL_PRIORITY)
.addClass(c)
.addClass(needs));
}
}
}
}