import cpp

/**

* A wrapper that provides metrics for a C/C++ file.

*/

class MetricFile extends File {

/** Gets the number of functions defined in this file. */

int getNumberOfTopLevelFunctions() {

result = count(Function f | f.isTopLevel() and f.getFile() = this)

}

/** Gets the number of classes defined in this file. */

int getNumberOfClasses() { result = count(Class c | c.getFile() = this) }

/** Gets the number of user-defined types defined in this file. */

int getNumberOfUserTypes() { result = count(UserType t | t.getFile() = this) }

/** Gets the number of lines in this file. */

int getNumberOfLines() { numlines(underlyingElement(this), result, _, _) }

/** Gets the number of lines of code in this file. */

int getNumberOfLinesOfCode() { numlines(underlyingElement(this), _, result, _) }

/** Gets the number of lines of comments in this file. */

int getNumberOfLinesOfComments() { numlines(underlyingElement(this), _, _, result) }

/** Gets the number of incoming file dependencies. */

int getAfferentCoupling() { result = count(MetricFile that | that.getAFileDependency() = this) }

/** Gets the number of outgoing file dependencies. */

int getEfferentCoupling() { result = count(MetricFile that | this.getAFileDependency() = that) }

/*

* HALSTEAD METRICS

*/

/**

* Gets the Halstead "N1" metric for this file. This is the total number of

* operators in the file. Operators are taken to be all operators in

* expressions (`+`, `*`, `&`, `->`, `=`, ...) as well as most statements.

*/

int getHalsteadN1() {

result =

sum(MetricFunction mf, int toSum | mf.getFile() = this and toSum = mf.getHalsteadN1() | toSum)

+

// Each class counts once as an operator

count(Class c | c.getFile() = this) +

// Each variable declaration that is not in a function counts once as an operator

count(GlobalVariable gv | gv.getFile() = this) +

count(MemberVariable mv | mv.getFile() = this) +

// Type declarations - to count the definition tokens

count(TypeDeclarationEntry decl | decl.getFile() = this) +

// Friend declarations

count(FriendDecl f | f.getFile() = this)

}

/**

* Gets the Halstead "N2" metric for this file: this is the total number of operands.

* An operand is either a variable, constant, type name, class name, or function name.

*/

int getHalsteadN2() {

result =

sum(MetricFunction mf, int toSum | mf.getFile() = this and toSum = mf.getHalsteadN2() | toSum)

+

// Each class counts once as an operand

count(Class c | c.getFile() = this) +

// Each variable declaration that is not in a function counts once as an operand

count(GlobalVariable gv | gv.getFile() = this) +

count(MemberVariable mv | mv.getFile() = this) +

// Type declarations - to count the type names

count(TypeDeclarationEntry decl | decl.getFile() = this) +

// Enum constant declarations to count the name

count(EnumConstant ec | ec.getFile() = this)

}

private string getAUsedHalsteadN1Operator() {

exists(CommaExpr e | e.getFile() = this) and result = "comma"

or

exists(ReferenceToExpr e | e.getFile() = this) and result = "refTo"

or

exists(PointerDereferenceExpr e | e.getFile() = this) and result = "dereference"

or

exists(CStyleCast e | e.getFile() = this) and result = "cCast"

or

exists(StaticCast e | e.getFile() = this) and result = "staticCast"

or

exists(ConstCast e | e.getFile() = this) and result = "constCast"

or

exists(ReinterpretCast e | e.getFile() = this) and result = "reinterpretCast"

or

exists(DynamicCast e | e.getFile() = this) and result = "dynamicCast"

or

exists(SizeofExprOperator e | e.getFile() = this) and result = "sizeofExpr"

or

exists(SizeofTypeOperator e | e.getFile() = this) and result = "sizeofType"

or

exists(IfStmt e | e.getFile() = this) and result = "ifVal"

or

exists(SwitchStmt e | e.getFile() = this) and result = "switchVal"

or

exists(ForStmt e | e.getFile() = this) and result = "forVal"

or

exists(DoStmt e | e.getFile() = this) and result = "doVal"

or

exists(WhileStmt e | e.getFile() = this) and result = "whileVal"

or

exists(GotoStmt e | e.getFile() = this) and result = "gotoVal"

or

exists(ContinueStmt e | e.getFile() = this) and result = "continueVal"

or

exists(BreakStmt e | e.getFile() = this) and result = "breakVal"

or

exists(ReturnStmt e | e.getFile() = this) and result = "returnVal"

or

exists(SwitchCase e | e.getFile() = this) and result = "caseVal"

or

exists(IfStmt s | s.getFile() = this and s.hasElse()) and

result = "elseVal"

or

exists(Function f | f.getFile() = this) and result = "function"

or

exists(Class c | c.getFile() = this) and result = "classDef"

or

exists(TypeDeclarationEntry e | e.getFile() = this) and result = "typeDecl"

or

exists(FriendDecl e | e.getFile() = this) and result = "friendDecl"

}

/**

* Gets the Halstead "n1" metric: this is the total number of distinct operators

* in this file. Operators are defined as in the "N1" metric (`getHalsteadN1`).

*/

int getHalsteadN1Distinct() {

result =

// avoid 0 values

1 + count(string s | exists(Operation op | op.getFile() = this and s = op.getOperator())) +

count(string s | s = this.getAUsedHalsteadN1Operator())

}

/**

* Gets the Halstead "n2" metric: this is the number of distinct operands in this

* file. An operand is either a variable, constant, type name, or function name.

*/

int getHalsteadN2Distinct() {

result =

// avoid 0 values

1 + count(string s | exists(Access a | a.getFile() = this and s = a.getTarget().getName())) +

count(Function f | exists(FunctionCall fc | fc.getFile() = this and f = fc.getTarget())) +

// Approximate: count declarations once more to account for the type name

count(Declaration d | d.getFile() = this)

}

/**

* Gets the Halstead length of this file. This is the sum of the N1 and N2 Halstead metrics.

*/

int getHalsteadLength() { result = this.getHalsteadN1() + this.getHalsteadN2() }

/**

* Gets the Halstead vocabulary size of this file. This is the sum of the n1 and n2 Halstead metrics.

*/

int getHalsteadVocabulary() {

result = this.getHalsteadN1Distinct() + this.getHalsteadN2Distinct()

}

/**

* Gets the Halstead volume of this file. This is the Halstead size multiplied by the log of the

* Halstead vocabulary. It represents the information content of the file.

*/

float getHalsteadVolume() {

result = this.getHalsteadLength().(float) * this.getHalsteadVocabulary().log2()

}

/**

* Gets the Halstead difficulty value of this file. This is proportional to the number of unique

* operators, and further proportional to the ratio of total operands to unique operands.

*/

float getHalsteadDifficulty() {

result =

(this.getHalsteadN1Distinct() * this.getHalsteadN2()).(float) /

(2 * this.getHalsteadN2Distinct()).(float)

}

/**

* Gets the Halstead level of this file. This is the inverse of the difficulty of the file.

*/

float getHalsteadLevel() {

exists(float difficulty |

difficulty = this.getHalsteadDifficulty() and

if difficulty != 0.0 then result = 1.0 / difficulty else result = 0.0

)

}

/**

* Gets the Halstead implementation effort for this file. This is the product of the volume and difficulty.

*/

float getHalsteadEffort() { result = this.getHalsteadVolume() * this.getHalsteadDifficulty() }

/**

* Gets the Halstead 'delivered bugs' metric for this file. This metric correlates with the complexity of

* the software, but is known to be an underestimate of bug counts.

*/

float getHalsteadDeliveredBugs() { result = this.getHalsteadEffort().pow(2.0 / 3.0) / 3000.0 }

/** Gets a file dependency of this file. */

File getAFileDependency() { dependsOnFileSimple(this, result.getMetrics()) }

}

private predicate aClassFile(Class c, File file) { c.getDefinitionLocation().getFile() = file }

pragma[noopt]

private predicate dependsOnFileSimple(MetricFile source, MetricFile dest) {

// class derives from another class

exists(Class fromClass, Class toClass |

aClassFile(fromClass, source) and

fromClass.derivesFrom(toClass) and

aClassFile(toClass, dest)

)

or

// class nested in another class

exists(Class fromClass, Class toClass |

aClassFile(fromClass, source) and

fromClass.getDeclaringType() = toClass and

toClass.getFile() = dest

)

or

// class has friend class

exists(Class fromClass, Class toClass, FriendDecl fd |

aClassFile(fromClass, source) and

fromClass.getAFriendDecl() = fd and

fd.getFriend() = toClass and

toClass instanceof Class and

dest = toClass.getFile()

)

or

exists(FunctionCall ca, Function f |

ca instanceof FunctionCall and

ca.getFile() = source and

ca.getTarget() = f and

f.getFile() = dest and

not f.isMultiplyDefined() and

not exists(Function ef | ef = ca.getEnclosingFunction() and ef.isMultiplyDefined())

)

or

exists(Access a, Declaration d |

a instanceof Access and

a.getFile() = source and

a.getTarget() = d and

d.getFile() = dest and

not exists(Function ef | ef = a.getEnclosingFunction() and ef.isMultiplyDefined())

)

or

exists(Variable v, VariableDeclarationEntry e, Type vt, UserType t |

e instanceof VariableDeclarationEntry and

e.getFile() = source and

v.getADeclarationEntry() = e and

vt = v.getType() and

vt.refersTo(t) and

t instanceof UserType and

t.getFile() = dest

)

or

exists(Function f, FunctionDeclarationEntry e, Type ft, UserType t |

e instanceof FunctionDeclarationEntry and

e.getFile() = source and

f.getADeclarationEntry() = e and

ft = f.getType() and

ft.refersTo(t) and

t instanceof UserType and

t.getFile() = dest

)

or

exists(MacroInvocation mi, Macro m |

mi instanceof MacroInvocation and

mi.getFile() = source and

mi.getMacro() = m and

m.getFile() = dest

)

or

exists(TypedefType t, TypeDeclarationEntry e, Type bt, UserType u |

e instanceof TypeDeclarationEntry and

e.getFile() = source and

t.getADeclarationEntry() = e and

bt = t.getBaseType() and

bt.refersTo(u) and

u instanceof UserType and

u.getFile() = dest

)

or

exists(Cast c, Type t, UserType u |

c instanceof Cast and

c.getFile() = source and

c.getType() = t and

t.refersTo(u) and

u instanceof UserType and

u.getFile() = dest and

not exists(Function ef | ef = c.getEnclosingFunction() and ef.isMultiplyDefined())

)

}