Class BuryingLogic

  • All Implemented Interfaces:
    edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, edu.umd.cs.findbugs.visitclass.Constants2, org.apache.bcel.classfile.Visitor, org.apache.bcel.Constants

    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 java.lang.String BURY_LOGIC_LOW_RATIO_PROPERTY  
      private static java.lang.String BURY_LOGIC_NORMAL_RATIO_PROPERTY  
      private java.util.BitSet casePositions  
      private java.util.BitSet catchPCs  
      private java.util.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 double LOW_BUG_RATIO_LIMIT  
      private double lowBugRatioLimit  
      private static double NORMAL_BUG_RATIO_LIMIT  
      private double normalBugRatioLimit  
      private static java.util.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 org.apache.bcel.Constants

        AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_SYPER, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACCESS_NAMES, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ANEWARRAY_QUICK, APPEND_FRAME, APPEND_FRAME_MAX, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, ATTR_ANNOTATION_DEFAULT, ATTR_CODE, ATTR_CONSTANT_VALUE, ATTR_DEPRECATED, ATTR_ENCLOSING_METHOD, ATTR_EXCEPTIONS, ATTR_INNER_CLASSES, ATTR_LINE_NUMBER_TABLE, ATTR_LOCAL_VARIABLE_TABLE, ATTR_LOCAL_VARIABLE_TYPE_TABLE, ATTR_PMG, ATTR_RUNTIME_VISIBLE_ANNOTATIONS, ATTR_RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS, ATTR_RUNTIMEIN_VISIBLE_ANNOTATIONS, ATTR_RUNTIMEIN_VISIBLE_PARAMETER_ANNOTATIONS, ATTR_SIGNATURE, ATTR_SOURCE_FILE, ATTR_STACK_MAP, ATTR_STACK_MAP_TABLE, ATTR_SYNTHETIC, ATTR_UNKNOWN, ATTRIBUTE_NAMES, BALOAD, BASTORE, BIPUSH, BREAKPOINT, CALOAD, CASTORE, CHECKCAST, CHECKCAST_QUICK, CHOP_FRAME, CHOP_FRAME_MAX, CLASS_TYPE_NAMES, CONSTANT_Class, CONSTANT_Double, CONSTANT_Fieldref, CONSTANT_Float, CONSTANT_Integer, CONSTANT_InterfaceMethodref, CONSTANT_InvokeDynamic, CONSTANT_Long, CONSTANT_MethodHandle, CONSTANT_Methodref, CONSTANT_MethodType, CONSTANT_NameAndType, CONSTANT_NAMES, CONSTANT_String, CONSTANT_Utf8, CONSTRUCTOR_NAME, CONSUME_STACK, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, DMUL, DNEG, DREM, DRETURN, DSTORE, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, FMUL, FNEG, FREM, FRETURN, FSTORE, FSTORE_0, FSTORE_1, FSTORE_2, FSTORE_3, FSUB, FULL_FRAME, GETFIELD, GETFIELD_QUICK, GETFIELD_QUICK_W, GETFIELD2_QUICK, GETSTATIC, GETSTATIC_QUICK, GETSTATIC2_QUICK, GOTO, GOTO_W, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILLEGAL_OPCODE, ILLEGAL_TYPE, ILOAD, ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, IMPDEP1, IMPDEP2, IMUL, INEG, INSTANCEOF, INSTANCEOF_QUICK, INT2BYTE, INT2CHAR, INT2SHORT, INTERFACES_IMPLEMENTED_BY_ARRAYS, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKEINTERFACE_QUICK, INVOKENONVIRTUAL, INVOKENONVIRTUAL_QUICK, INVOKESPECIAL, INVOKESTATIC, INVOKESTATIC_QUICK, INVOKESUPER_QUICK, INVOKEVIRTUAL, INVOKEVIRTUAL_QUICK, INVOKEVIRTUAL_QUICK_W, INVOKEVIRTUALOBJECT_QUICK, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, ISUB, ITEM_Bogus, ITEM_Double, ITEM_Float, ITEM_InitObject, ITEM_Integer, ITEM_Long, ITEM_NAMES, ITEM_NewObject, ITEM_Null, ITEM_Object, IUSHR, IXOR, JSR, JSR_W, KNOWN_ATTRIBUTES, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDC_QUICK, LDC_W, LDC_W_QUICK, LDC2_W, LDC2_W_QUICK, LDIV, LLOAD, LLOAD_0, LLOAD_1, LLOAD_2, LLOAD_3, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, LSUB, LUSHR, LXOR, MAJOR, MAJOR_1_1, MAJOR_1_2, MAJOR_1_3, MAJOR_1_4, MAJOR_1_5, MAJOR_1_6, MAJOR_1_7, MAJOR_1_8, MAX_ACC_FLAG, MAX_BYTE, MAX_CODE_SIZE, MAX_CP_ENTRIES, MAX_SHORT, MINOR, MINOR_1_1, MINOR_1_2, MINOR_1_3, MINOR_1_4, MINOR_1_5, MINOR_1_6, MINOR_1_7, MINOR_1_8, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, MULTIANEWARRAY_QUICK, NEW, NEW_QUICK, NEWARRAY, NO_OF_OPERANDS, NOP, OPCODE_NAMES, POP, POP2, PRODUCE_STACK, PUSH, PUTFIELD, PUTFIELD_QUICK, PUTFIELD_QUICK_W, PUTFIELD2_QUICK, PUTSTATIC, PUTSTATIC_QUICK, PUTSTATIC2_QUICK, RESERVED, RET, RETURN, SALOAD, SAME_FRAME, SAME_FRAME_EXTENDED, SAME_FRAME_MAX, SAME_LOCALS_1_STACK_ITEM_FRAME, SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED, SAME_LOCALS_1_STACK_ITEM_FRAME_MAX, SASTORE, SHORT_TYPE_NAMES, SIPUSH, STATIC_INITIALIZER_NAME, SWAP, SWITCH, T_ADDRESS, T_ARRAY, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_OBJECT, T_REFERENCE, T_SHORT, T_UNKNOWN, T_VOID, TABLESWITCH, TYPE_NAMES, TYPE_OF_OPERANDS, UNDEFINED, UNPREDICTABLE, WIDE
      • 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

      All Methods Instance Methods Concrete Methods 
      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

        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, getSurroundingTryBlock, getSurroundingTryBlock, getThisClass, getXClass, getXField, getXMethod, hasInterestingClass, hasInterestingMethod, isVisitMethodsInCallOrder, setupVisitorForClass, setVisitMethodsInCallOrder, shouldVisit, toString, visitAfter, visitAfter, visitAnnotationDefault, visitAnnotationEntry, visitConstantPool, visitEnclosingMethod, visitingField, visitingMethod, visitInnerClasses, visitJavaClass, visitLineNumberTable, visitLocalVariableTable, visitStackMapTable, visitStackMapTableEntry
      • 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, visitStackMap, visitStackMapEntry, visitSynthetic, visitUnknown
      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Field Detail

      • BURY_LOGIC_LOW_RATIO_PROPERTY

        private static final java.lang.String BURY_LOGIC_LOW_RATIO_PROPERTY
        See Also:
        Constant Field Values
      • BURY_LOGIC_NORMAL_RATIO_PROPERTY

        private static final java.lang.String BURY_LOGIC_NORMAL_RATIO_PROPERTY
        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 java.util.BitSet resetOps
      • bugReporter

        private edu.umd.cs.findbugs.BugReporter bugReporter
      • stack

        private edu.umd.cs.findbugs.OpcodeStack stack
      • activeUnconditional

        private BuryingLogic.IfBlock activeUnconditional
        if an previous if block has been closed off with a return, hold onto it.
      • casePositions

        private java.util.BitSet casePositions
      • lowBugRatioLimit

        private double lowBugRatioLimit
      • normalBugRatioLimit

        private double normalBugRatioLimit
      • catchPCs

        private java.util.BitSet catchPCs
      • gotoBranchPCs

        private java.util.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 Detail

      • 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 Detail

      • 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