/*
* fb-contrib - Auxiliary detectors for Java programs
* Copyright (C) 2005-2017 Dave Brosius
*
* 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 com.mebigfatguy.fbcontrib.detect;
import org.apache.bcel.classfile.Code;
import com.mebigfatguy.fbcontrib.utils.BugType;
import com.mebigfatguy.fbcontrib.utils.SignatureBuilder;
import com.mebigfatguy.fbcontrib.utils.Values;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
/**
* looks for methods that set a setter with the value obtained from the same
* bean's complimentary getter. This is usually a typo.
*/
public class SuspiciousGetterSetterUse extends BytecodeScanningDetector {
private static enum State {
SEEN_NOTHING, SEEN_ALOAD, SEEN_GETFIELD, SEEN_DUAL_LOADS, SEEN_INVOKEVIRTUAL
};
private final BugReporter bugReporter;
private State state;
private String beanReference1;
private String beanReference2;
private String propName;
private String propType;
private boolean sawField;
/**
* constructs a SGSU detector given the reporter to report bugs on
*
* @param bugReporter
* the sync of bug reports
*/
public SuspiciousGetterSetterUse(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
/**
* overrides the visitor to reset the state to SEEN_NOTHING, and clear the
* beanReference, propName and propType
*
* @param obj
* the context object of the currently parsed code block
*/
@Override
public void visitCode(Code obj) {
state = State.SEEN_NOTHING;
beanReference1 = null;
beanReference2 = null;
propName = null;
propType = null;
sawField = false;
super.visitCode(obj);
}
/**
* overrides the visitor to look for a setXXX with the value returned from a
* getXXX using the same base object.
*
* @param seen
* the currently parsed opcode
*/
@Override
public void sawOpcode(int seen) {
boolean reset = true;
switch (state) { // TODO: Refactor this to use state pattern, not nested
// switches
case SEEN_NOTHING:
reset = sawOpcodeAfterNothing(seen);
break;
case SEEN_ALOAD:
reset = sawOpcodeAfterLoad(seen);
break;
case SEEN_GETFIELD:
reset = sawOpcodeAfterGetField(seen);
break;
case SEEN_DUAL_LOADS:
reset = sawOpcodeAfterDualLoads(seen);
break;
case SEEN_INVOKEVIRTUAL:
if (seen == INVOKEVIRTUAL) {
checkForSGSU();
}
break;
}
if (reset) {
beanReference1 = null;
beanReference2 = null;
propType = null;
propName = null;
sawField = false;
state = State.SEEN_NOTHING;
}
}
private boolean sawOpcodeAfterNothing(int seen) {
switch (seen) {
case ALOAD:
case ALOAD_0:
case ALOAD_1:
case ALOAD_2:
case ALOAD_3:
beanReference1 = String.valueOf(getRegisterOperand());
state = State.SEEN_ALOAD;
return false;
default:
return true;
}
}
private boolean sawOpcodeAfterLoad(int seen) {
switch (seen) {
case ALOAD:
case ALOAD_0:
case ALOAD_1:
case ALOAD_2:
case ALOAD_3:
if (!sawField && beanReference1.equals(String.valueOf(getRegisterOperand()))) {
state = State.SEEN_DUAL_LOADS;
return false;
}
break;
case GETFIELD: {
if (sawField) {
beanReference2 += ':' + getNameConstantOperand();
if (beanReference1.equals(beanReference2)) {
state = State.SEEN_DUAL_LOADS;
return false;
}
} else {
state = State.SEEN_GETFIELD;
beanReference1 += ':' + getNameConstantOperand();
sawField = true;
return false;
}
}
break;
default:
break;
}
return true;
}
private boolean sawOpcodeAfterGetField(int seen) {
switch (seen) {
case ALOAD:
case ALOAD_0:
case ALOAD_1:
case ALOAD_2:
case ALOAD_3:
beanReference2 = String.valueOf(getRegisterOperand());
state = State.SEEN_ALOAD;
return false;
default:
return true;
}
}
private boolean sawOpcodeAfterDualLoads(int seen) {
if (seen != INVOKEVIRTUAL) {
return true;
}
String sig = getSigConstantOperand();
String noParams = SignatureBuilder.PARAM_NONE;
if (!sig.startsWith(noParams)) {
return true;
}
propType = sig.substring(noParams.length());
if (Values.SIG_VOID.equals(propType)) {
return true;
}
String methodName = getNameConstantOperand();
if (!methodName.startsWith("get")) {
return true;
}
propName = methodName.substring("get".length());
state = State.SEEN_INVOKEVIRTUAL;
return false;
}
private void checkForSGSU() {
if (!getSigConstantOperand().equals('(' + propType + ")V")) {
return;
}
String name = getNameConstantOperand();
if (name.startsWith("set") && propName.equals(name.substring("set".length()))) {
bugReporter.reportBug(new BugInstance(this, BugType.SGSU_SUSPICIOUS_GETTER_SETTER_USE.name(), NORMAL_PRIORITY).addClass(this)
.addMethod(this).addSourceLine(this));
}
}
}