/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2004,2005 Dave Brosius <dbrosius@users.sourceforge.net>
* Copyright (C) 2004,2005 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 org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.Method;
import edu.umd.cs.findbugs.BugAccumulator;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.MethodAnnotation;
import edu.umd.cs.findbugs.StatelessDetector;
import edu.umd.cs.findbugs.ba.XClass;
import edu.umd.cs.findbugs.classfile.CheckedAnalysisException;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;
import edu.umd.cs.findbugs.classfile.Global;
public class WrongMapIterator extends BytecodeScanningDetector implements StatelessDetector {
private BugAccumulator bugAccumulator;
private static final int SAW_NOTHING = 0;
private static final int SAW_MAP_LOAD1 = 1;
private static final int SAW_KEYSET = 2;
private static final int SAW_KEYSET_STORE = 3;
private static final int SAW_ITERATOR = 4;
private static final int SAW_ITERATOR_STORE = 5;
private static final int SAW_ITERATOR_LOAD = 6;
private static final int SAW_NEXT = 7;
private static final int SAW_CHECKCAST_ON_NEXT = 8;
private static final int SAW_KEY_STORE = 9;
private static final int NEED_KEYSET_LOAD = 10;
private static final int SAW_MAP_LOAD2 = 11;
private static final int SAW_KEY_LOAD = 12;
private int state;
private int loadedRegister;
private int mapRegister;
private int keySetRegister;
private int iteratorRegister;
private int keyRegister;
public WrongMapIterator(BugReporter bugReporter) {
this.bugAccumulator = new BugAccumulator(bugReporter);
}
@Override
public void visit(Method obj) {
state = SAW_NOTHING;
loadedRegister = -1;
mapRegister = -1;
keySetRegister = -1;
iteratorRegister = -1;
keyRegister = -1;
}
@Override
public void visit(Code code) {
super.visit(code);
bugAccumulator.reportAccumulatedBugs();
}
/**
* Determine from the class descriptor for a variable whether that variable
* implements java.util.Map.
* @param d class descriptor for variable we want to check implements Map
* @return true iff the descriptor corresponds to an implementor of Map
*/
private static boolean implementsMap(ClassDescriptor d) {
while(d != null) {
try {
// True if variable is itself declared as a Map
if("java.util.Map".equals(d.getDottedClassName())) {
return true;
}
XClass classNameAndInfo =
Global.getAnalysisCache().
getClassAnalysis(XClass.class, d);
ClassDescriptor is[] =
classNameAndInfo.getInterfaceDescriptorList();
d = classNameAndInfo.getSuperclassDescriptor();
for(ClassDescriptor i : is) {
if("java.util.Map".equals(i.getDottedClassName())) {
return true;
}
}
} catch (CheckedAnalysisException e) {
d = null;
}
}
return false;
}
@Override
public void sawOpcode(int seen) {
switch (state)
{
case SAW_NOTHING:
loadedRegister = getLoadStoreRegister( seen, true );
if (loadedRegister >= 0)
state = SAW_MAP_LOAD1;
break;
case SAW_MAP_LOAD1:
// Doesn't check to see if the target object is a Map
if (((seen == INVOKEINTERFACE) || (seen == INVOKEVIRTUAL))
&& ("keySet".equals(getNameConstantOperand()))
&& ("()Ljava/util/Set;".equals(getSigConstantOperand()))
// Following check solves sourceforge bug 1830576
&& implementsMap(getClassDescriptorOperand())) {
mapRegister = loadedRegister;
state = SAW_KEYSET;
}
else {
state = SAW_NOTHING;
}
break;
case SAW_KEYSET:
keySetRegister = getLoadStoreRegister( seen, false );
if (keySetRegister >= 0)
state = SAW_KEYSET_STORE;
else if ((seen == INVOKEINTERFACE)
&& ("iterator".equals(getNameConstantOperand()))
&& ("()Ljava/util/Iterator;".equals(getSigConstantOperand())))
state = SAW_ITERATOR;
else
state = SAW_NOTHING;
break;
case SAW_KEYSET_STORE:
if ((seen == INVOKEINTERFACE)
&& ("iterator".equals(getNameConstantOperand()))
&& ("()Ljava/util/Iterator;".equals(getSigConstantOperand())))
state = SAW_ITERATOR;
else
state = NEED_KEYSET_LOAD;
break;
case NEED_KEYSET_LOAD:
loadedRegister = getLoadStoreRegister( seen, true );
if (loadedRegister == iteratorRegister)
state = SAW_ITERATOR;
break;
case SAW_ITERATOR:
iteratorRegister = getLoadStoreRegister( seen, false );
if (iteratorRegister >= 0)
state = SAW_ITERATOR_STORE;
else
state = SAW_NOTHING;
break;
case SAW_ITERATOR_STORE:
loadedRegister = getLoadStoreRegister( seen, true );
if (loadedRegister == iteratorRegister)
state = SAW_ITERATOR_LOAD;
break;
case SAW_ITERATOR_LOAD:
if ((seen == INVOKEINTERFACE)
&& ("next".equals(getNameConstantOperand()))
&& ("()Ljava/lang/Object;".equals(getSigConstantOperand())))
state = SAW_NEXT;
else
state = SAW_ITERATOR_STORE;
break;
case SAW_NEXT:
if (seen == CHECKCAST)
state = SAW_CHECKCAST_ON_NEXT;
else {
keyRegister = getLoadStoreRegister( seen, false );
if (keyRegister >= 0)
state = SAW_KEY_STORE;
else
state = SAW_NOTHING;
}
break;
case SAW_CHECKCAST_ON_NEXT:
keyRegister = getLoadStoreRegister( seen, false );
if (keyRegister >= 0)
state = SAW_KEY_STORE;
break;
case SAW_KEY_STORE:
loadedRegister = getLoadStoreRegister( seen, true );
if (loadedRegister == mapRegister)
state = SAW_MAP_LOAD2;
break;
case SAW_MAP_LOAD2:
loadedRegister = getLoadStoreRegister( seen, true );
if (loadedRegister == keyRegister)
state = SAW_KEY_LOAD;
else
state = SAW_KEY_STORE;
break;
case SAW_KEY_LOAD:
if (((seen == INVOKEINTERFACE) || (seen == INVOKEVIRTUAL))
&& ("get".equals(getNameConstantOperand()))
&& ("(Ljava/lang/Object;)Ljava/lang/Object;".equals(getSigConstantOperand()))) {
MethodAnnotation ma = MethodAnnotation.fromVisitedMethod(this);
bugAccumulator.accumulateBug(
new BugInstance(this, "WMI_WRONG_MAP_ITERATOR", NORMAL_PRIORITY)
.addClass(this)
.addMethod(ma),this);
state = SAW_NOTHING;
}
break;
}
}
private int getLoadStoreRegister(int seen, boolean doLoad)
{
switch (seen)
{
case ALOAD_0:
case ALOAD_1:
case ALOAD_2:
case ALOAD_3:
if (doLoad)
return seen - ALOAD_0;
break;
case ALOAD:
if (doLoad)
return getRegisterOperand();
break;
case ASTORE_0:
case ASTORE_1:
case ASTORE_2:
case ASTORE_3:
if (!doLoad)
return seen - ASTORE_0;
break;
case ASTORE:
if (!doLoad)
return getRegisterOperand();
break;
}
return -1;
}
}