Package com.mebigfatguy.fbcontrib.detect

Class BuryingLogic

java.lang.Object

edu.umd.cs.findbugs.visitclass.BetterVisitor

edu.umd.cs.findbugs.visitclass.PreorderVisitor

edu.umd.cs.findbugs.visitclass.AnnotationVisitor

edu.umd.cs.findbugs.visitclass.DismantleBytecode

edu.umd.cs.findbugs.BytecodeScanningDetector

com.mebigfatguy.fbcontrib.detect.BuryingLogic

All Implemented Interfaces:

edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, org.apache.bcel.classfile.Visitor

public class BuryingLogic
extends edu.umd.cs.findbugs.BytecodeScanningDetector

looks for relatively large if blocks of code, where you unconditionally return from them, and then follow that with an unconditional return of a small block. This places the bulk of the logic to the right indentation-wise, making it more difficult to read than needed. It would be better to invert the logic of the if block, and immediately return, allowing the bulk of the logic to be move to the left, for easier reading.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	BuryingLogic.IfBlock	represents the byte offset code range of code that is executed inside an if block
(package private) static class	BuryingLogic.IfBlocks	represents all the if blocks in a method

Field Summary

Fields

Modifier and Type	Field	Description
private BuryingLogic.IfBlock	activeUnconditional	if an previous if block has been closed off with a return, hold onto it.
private edu.umd.cs.findbugs.BugReporter	bugReporter
private static final String	BURY_LOGIC_LOW_RATIO_PROPERTY
private static final String	BURY_LOGIC_NORMAL_RATIO_PROPERTY
private BitSet	casePositions
private BitSet	catchPCs
private BitSet	gotoBranchPCs
private BuryingLogic.IfBlocks	ifBlocks
private boolean	lookingForResetOp	if we've processed an if block, we want to avoid else ifs, so don't start looking for a new if branch, until some instruction that can't be part of a conditional is found
private static final double	LOW_BUG_RATIO_LIMIT
private double	lowBugRatioLimit
private static final double	NORMAL_BUG_RATIO_LIMIT
private double	normalBugRatioLimit
private static final BitSet	resetOps
private edu.umd.cs.findbugs.OpcodeStack	stack

Fields inherited from class edu.umd.cs.findbugs.visitclass.DismantleBytecode

codeBytes, lineNumberTable, M_BR, M_CP, M_INT, M_PAD, M_R, M_UINT

Fields inherited from interface edu.umd.cs.findbugs.Priorities

EXP_PRIORITY, HIGH_PRIORITY, IGNORE_PRIORITY, LOW_PRIORITY, NORMAL_PRIORITY

Constructor Summary

Constructors

Constructor	Description
BuryingLogic(edu.umd.cs.findbugs.BugReporter bugReporter)	constructs a BL detector given the reporter to report bugs on

Method Summary

Modifier and Type	Method	Description
private boolean	gotoAcrossPC(int pc)	returns whether the last downward branching jump seen crosses over the current location
private boolean	isResetOp(int seen)	determines if this opcode couldn't be part of a conditional expression or at least is very unlikely to be so.
void	sawOpcode(int seen)	the difficult problem is to figure out when you are at the bottom of an if/else chain when all the above if/else blocks leave via returns.
void	visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)	implements the visitor to reset the opcode stack, and initialize if tracking collections
void	visitCode(org.apache.bcel.classfile.Code obj)

Methods inherited from class edu.umd.cs.findbugs.BytecodeScanningDetector

getClassContext, report, shouldVisitCode

Methods inherited from class edu.umd.cs.findbugs.visitclass.DismantleBytecode

afterOpcode, areOppositeBranches, atCatchBlock, beforeOpcode, getBranchFallThrough, getBranchOffset, getBranchTarget, getClassConstantOperand, getClassDescriptorOperand, getCodeByte, getConstantRefOperand, getDefaultSwitchOffset, getDottedClassConstantOperand, getFieldDescriptorOperand, getIntConstant, getLongConstant, getMaxPC, getMethodDescriptorOperand, getNameConstantOperand, getNextCodeByte, getNextOpcode, getNextPC, getOpcode, getPC, getPrevOpcode, getRefConstantOperand, getRefFieldIsStatic, getRegisterOperand, getSigConstantOperand, getStringConstantOperand, getSwitchLabels, getSwitchOffsets, getXClassOperand, getXFieldOperand, getXMethodOperand, isBranch, isMethodCall, isRegisterLoad, isRegisterStore, isRegisterStore, isReturn, isShift, isSwitch, isWideOpcode, printOpCode, sawBranchTo, sawClass, sawDouble, sawField, sawFloat, sawIMethod, sawInt, sawLong, sawMethod, sawRegister, sawString, visit

Methods inherited from class edu.umd.cs.findbugs.visitclass.AnnotationVisitor

getAnnotationParameterAsEnum, getAnnotationParameterAsString, getAnnotationParameterAsStringArray, visitAnnotation, visitAnnotation, visitParameterAnnotation, visitParameterAnnotation, visitSyntheticParameterAnnotation

Methods inherited from class edu.umd.cs.findbugs.visitclass.PreorderVisitor

amVisitingMainMethod, asUnsignedByte, doVisitMethod, getClassDescriptor, getClassName, getCode, getConstantPool, getDottedClassName, getDottedFieldSig, getDottedMethodSig, getDottedSuperclassName, getField, getFieldDescriptor, getFieldIsStatic, getFieldName, getFieldSig, getFullyQualifiedFieldName, getFullyQualifiedMethodName, getMethod, getMethodDescriptor, getMethodName, getMethodSig, getMethodVisitOrder, getNumberArguments, getNumberMethodArguments, getPackageName, getSizeOfSurroundingTryBlock, getSizeOfSurroundingTryBlock, getSourceFile, getStringFromIndex, getSuperclassName, getSurroundingCaughtExceptions, getSurroundingCaughtExceptions, getSurroundingCaughtExceptionTypes, getSurroundingTryBlock, getSurroundingTryBlock, getThisClass, getXClass, getXField, getXMethod, hasInterestingClass, hasInterestingMethod, isVisitMethodsInCallOrder, setupVisitorForClass, setVisitMethodsInCallOrder, shouldVisit, toString, visitAfter, visitAfter, visitAnnotationDefault, visitAnnotationEntry, visitBootstrapMethods, visitConstantInvokeDynamic, visitConstantMethodHandle, visitConstantMethodType, visitConstantModule, visitConstantPackage, visitConstantPool, visitEnclosingMethod, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable, visitMethodParameters, visitParameterAnnotationEntry, visitStackMap, visitStackMapEntry

Methods inherited from class edu.umd.cs.findbugs.visitclass.BetterVisitor

clone, report, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visitCodeException, visitConstantClass, visitConstantDouble, visitConstantFieldref, visitConstantFloat, visitConstantInteger, visitConstantInterfaceMethodref, visitConstantLong, visitConstantMethodref, visitConstantNameAndType, visitConstantString, visitConstantUtf8, visitConstantValue, visitDeprecated, visitExceptionTable, visitField, visitInnerClass, visitLineNumber, visitLocalVariable, visitLocalVariableTypeTable, visitMethod, visitSignature, visitSourceFile, visitSynthetic, visitUnknown

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.bcel.classfile.Visitor

visitConstantDynamic, visitMethodParameter, visitModule, visitModuleExports, visitModuleMainClass, visitModuleOpens, visitModulePackages, visitModuleProvides, visitModuleRequires, visitNestHost, visitNestMembers, visitRecord, visitRecordComponent, visitStackMapType

Field Details

BURY_LOGIC_LOW_RATIO_PROPERTY

private static final String BURY_LOGIC_LOW_RATIO_PROPERTY

See Also:

• Constant Field Values

BURY_LOGIC_NORMAL_RATIO_PROPERTY

private static final String BURY_LOGIC_NORMAL_RATIO_PROPERTY

See Also:

• Constant Field Values

LOW_BUG_RATIO_LIMIT

private static final double LOW_BUG_RATIO_LIMIT

See Also:

• Constant Field Values

NORMAL_BUG_RATIO_LIMIT

private static final double NORMAL_BUG_RATIO_LIMIT

See Also:

• Constant Field Values

resetOps

private static final BitSet resetOps

bugReporter

private edu.umd.cs.findbugs.BugReporter bugReporter

stack

private edu.umd.cs.findbugs.OpcodeStack stack

ifBlocks

private BuryingLogic.IfBlocks ifBlocks

activeUnconditional

private BuryingLogic.IfBlock activeUnconditional

if an previous if block has been closed off with a return, hold onto it.

casePositions

private BitSet casePositions

lowBugRatioLimit

private double lowBugRatioLimit

normalBugRatioLimit

private double normalBugRatioLimit

catchPCs

private BitSet catchPCs

gotoBranchPCs

private BitSet gotoBranchPCs

lookingForResetOp

private boolean lookingForResetOp

if we've processed an if block, we want to avoid else ifs, so don't start looking for a new if branch, until some instruction that can't be part of a conditional is found

Constructor Details

BuryingLogic

public BuryingLogic(edu.umd.cs.findbugs.BugReporter bugReporter)

constructs a BL detector given the reporter to report bugs on

Parameters:

bugReporter - the sync of bug reports

Method Details

visitClassContext

public void visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)

implements the visitor to reset the opcode stack, and initialize if tracking collections

Specified by:

visitClassContext in interface edu.umd.cs.findbugs.Detector

Overrides:

visitClassContext in class edu.umd.cs.findbugs.BytecodeScanningDetector

Parameters:

classContext - the currently parsed java class

visitCode

public void visitCode(org.apache.bcel.classfile.Code obj)

Specified by:

visitCode in interface org.apache.bcel.classfile.Visitor

Overrides:

visitCode in class edu.umd.cs.findbugs.visitclass.PreorderVisitor

sawOpcode

public void sawOpcode(int seen)

the difficult problem is to figure out when you are at the bottom of an if/else chain when all the above if/else blocks leave via returns. then there is only one branch target to the statement after the last else, which is indistinquishable from a simple if/else.

Overrides:

sawOpcode in class edu.umd.cs.findbugs.visitclass.DismantleBytecode

gotoAcrossPC

private boolean gotoAcrossPC(int pc)

returns whether the last downward branching jump seen crosses over the current location

Parameters:

pc - the current location

Returns:

if the last if statement branched over here

isResetOp

private boolean isResetOp(int seen)

determines if this opcode couldn't be part of a conditional expression or at least is very unlikely to be so.

Parameters:

seen - the currently parse opcode

Returns:

if this operation resets the looking for conditionals