Package com.mebigfatguy.fbcontrib.detect

Class LiteralStringComparison

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.LiteralStringComparison
All Implemented Interfaces:
edu.umd.cs.findbugs.Detector, edu.umd.cs.findbugs.Priorities, org.apache.bcel.classfile.Visitor
@CustomUserValue public class LiteralStringComparison extends edu.umd.cs.findbugs.BytecodeScanningDetector
looks for methods that compare strings against literal strings, where the literal string is passed as the parameter. If the .equals or .compareTo is called on the literal itself, passing the variable as the parameter, you avoid the possibility of a NullPointerException. Updated for 1.7 to not throw false positives for string-based switch statements (which are susceptible to NPEs). String-based switch generate String.equals(Constant) bytecodes, and thus, must be accounted for

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    (package private) static class 
    LiteralStringComparison.LookupDetails
    holds information about a switch statement, and it's case PC values

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private edu.umd.cs.findbugs.BugReporter
    bugReporter
     
    private List<LiteralStringComparison.LookupDetails>
    lookupSwitches
    the object that was switched on, to the switch targets for that switch
    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
    LiteralStringComparison(edu.umd.cs.findbugs.BugReporter bugReporter)
    constructs a LSC detector given the reporter to report bugs on

  • Method Summary

    Modifier and Type
    Method
    Description
    private boolean
    lookupSwitchOnString()
    looks to see if the string used in a equals or compareTo is the same as that of a switch statement's switch on string.
    boolean
    prescreen(org.apache.bcel.classfile.Method method)
    looks for methods that contain a LDC or LDC_W opcodes
    void
    sawOpcode(int seen)
    looks for strings comparisons where the stack object is a literal
    void
    visitClassContext(edu.umd.cs.findbugs.ba.ClassContext classContext)
    implements the visitor to create and clear the stack
    void
    visitCode(org.apache.bcel.classfile.Code obj)
    overrides the visitor to reset the opcode stack

    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

    • bugReporter

      private edu.umd.cs.findbugs.BugReporter bugReporter

    • stack

      private edu.umd.cs.findbugs.OpcodeStack stack

    • lookupSwitches

      private List<LiteralStringComparison.LookupDetails> lookupSwitches
      the object that was switched on, to the switch targets for that switch

  • Constructor Details

    • LiteralStringComparison

      public LiteralStringComparison(edu.umd.cs.findbugs.BugReporter bugReporter)
      constructs a LSC 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 create and clear the stack
      Specified by:
      visitClassContext in interface edu.umd.cs.findbugs.Detector
      Overrides:
      visitClassContext in class edu.umd.cs.findbugs.BytecodeScanningDetector
      Parameters:
      classContext - the context object for the currently parsed class

    • prescreen

      public boolean prescreen(org.apache.bcel.classfile.Method method)
      looks for methods that contain a LDC or LDC_W opcodes
      Parameters:
      method - the context object of the current method
      Returns:
      if the class loads Const

    • visitCode

      public void visitCode(org.apache.bcel.classfile.Code obj)
      overrides the visitor to reset the opcode stack
      Specified by:
      visitCode in interface org.apache.bcel.classfile.Visitor
      Overrides:
      visitCode in class edu.umd.cs.findbugs.visitclass.PreorderVisitor
      Parameters:
      obj - the code object for the currently parsed method

    • sawOpcode

      public void sawOpcode(int seen)
      looks for strings comparisons where the stack object is a literal
      Overrides:
      sawOpcode in class edu.umd.cs.findbugs.visitclass.DismantleBytecode
      Parameters:
      seen - the currently parsed opcode

    • lookupSwitchOnString

      private boolean lookupSwitchOnString()
      looks to see if the string used in a equals or compareTo is the same as that of a switch statement's switch on string.
      Returns:
      if the string is used in a switch