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, edu.umd.cs.findbugs.visitclass.Constants2, org.apache.bcel.classfile.Visitor, org.apache.bcel.Constants

@OpcodeStack.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 and 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 and Description
private edu.umd.cs.findbugs.BugReporter	bugReporter
private java.util.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

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

Constructor Summary

Constructors

Constructor and 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 and 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

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

bugReporter

private edu.umd.cs.findbugs.BugReporter bugReporter

stack

private edu.umd.cs.findbugs.OpcodeStack stack

lookupSwitches

private java.util.List<LiteralStringComparison.LookupDetails> lookupSwitches

the object that was switched on, to the switch targets for that switch

Constructor Detail

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 Detail

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 constants

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