/
MisplacedNullCheckRule.cpp
189 lines (157 loc) · 4.53 KB
/
MisplacedNullCheckRule.cpp
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#include "oclint/AbstractASTVisitorRule.h"
#include "oclint/RuleSet.h"
#include "../abstract/AbstractNullCheckRule.h"
using namespace std;
using namespace clang;
using namespace oclint;
class MisplacedNullCheckBaseRule : public AbstractNullCheckRule<MisplacedNullCheckBaseRule>
{
private:
bool isEqNullCheckMisplaced(BinaryOperator *binaryOperator)
{
return binaryOperator->getOpcode() == BO_LAnd && isNeNullCheck(binaryOperator->getRHS());
}
bool isNeNullCheckMisplaced(BinaryOperator *binaryOperator)
{
return binaryOperator->getOpcode() == BO_LOr && isEqNullCheck(binaryOperator->getRHS());
}
bool isNullCheckMisplaced(BinaryOperator *binaryOperator)
{
return isEqNullCheckMisplaced(binaryOperator) || isNeNullCheckMisplaced(binaryOperator);
}
bool isSameVariableMisplaced(BinaryOperator *binaryOperator)
{
string variableOfInterest = extractIdentifierFromExpr(binaryOperator->getRHS());
return variableOfInterest == "" ? false :
hasVariableInExpr(variableOfInterest, binaryOperator->getLHS());
}
protected:
virtual bool hasVariableInExpr(string variableOfInterest, Expr *expr) = 0;
public:
bool VisitBinaryOperator(BinaryOperator *binaryOperator)
{
if (isNullCheckMisplaced(binaryOperator) && isSameVariableMisplaced(binaryOperator))
{
addViolation(binaryOperator, this);
}
return true;
}
};
class MisplacedNullCheckRule : public MisplacedNullCheckBaseRule
{
protected:
virtual bool hasVariableInExpr(string variableOfInterest, Expr* expr)
override
{
VariableOfInterestInMemberExpr seekingVariable;
return seekingVariable.hasVariableInExpr(variableOfInterest, expr, this);
}
public:
virtual const string name() const override
{
return "misplaced null check";
}
virtual int priority() const override
{
return 1;
}
virtual const string category() const override
{
return "basic";
}
virtual unsigned int supportedLanguages() const override
{
return LANG_C | LANG_CXX;
}
#ifdef DOCGEN
virtual const std::string since() const override
{
return "0.7";
}
virtual const std::string description() const override
{
return "The null check is misplaced. "
"In C and C++, sending a message to a null pointer could crash the program. "
"When null is misplaced, either the check is useless or it's incorrect.";
}
virtual const std::string fileName() const override
{
return "MisplacedNullCheckRule.cpp";
}
virtual const std::string example() const override
{
return R"rst(
.. code-block:: cpp
void m(A *a, B *b)
{
if (a->bar(b) && a != NULL) // violation
{
}
if (a->bar(b) || !a) // violation
{
}
}
)rst";
}
#endif
};
class MisplacedNilCheckRule : public MisplacedNullCheckBaseRule
{
protected:
virtual bool hasVariableInExpr(string variableOfInterest, Expr* expr)
override
{
VariableOfInterestInObjCMessageExpr seekingVariable;
return seekingVariable.hasVariableInExpr(variableOfInterest, expr, this);
}
public:
virtual const string name() const override
{
return "misplaced nil check";
}
virtual int priority() const override
{
return 3;
}
virtual const string category() const override
{
return "basic";
}
virtual unsigned int supportedLanguages() const override
{
return LANG_OBJC;
}
#ifdef DOCGEN
virtual const std::string since() const override
{
return "0.7";
}
virtual const std::string description() const override
{
return "The nil check is misplaced. "
"In Objective-C, sending a message to a nil pointer simply does nothing. "
"But code readers may be confused about the misplaced nil check.";
}
virtual const std::string fileName() const override
{
return "MisplacedNullCheckRule.cpp";
}
virtual const std::string example() const override
{
return R"rst(
.. code-block:: objective-c
+ (void)compare:(A *)obj1 withOther:(A *)obj2
{
if ([obj1 isEqualTo:obj2] && obj1)
{
}
if (![obj1 isEqualTo:obj2] || obj1 == nil)
{
}
}
)rst";
}
#endif
};
static RuleSet rulesMisplacedNull(new MisplacedNullCheckRule());
static RuleSet rulesMisplacedNil(new MisplacedNilCheckRule());