/**
* One var can be pointed by multiples accesses. This method leaves only one access per variable
* in the list
*/
private List<CtVariableAccess> cleanRepeatedAccesses(List<CtVariableAccess> allAccess) {
// Have only one access per variable
HashSet<String> varSignatures = new HashSet<>();
List<CtVariableAccess> access = new ArrayList<>();
for (CtVariableAccess a : allAccess) {
if (isFieldOfPrimitiveArray(a)) continue;
String signature = "";
if (a instanceof CtFieldAccess && ((CtFieldAccess) a).getTarget() != null)
signature = ((CtFieldAccess) a).getTarget().toString();
signature += a.getVariable().getSimpleName() + a.getVariable().getClass().getSimpleName();
if (!varSignatures.contains(signature)) {
varSignatures.add(signature);
access.add(a);
}
}
varSignatures.clear();
return access;
}
@Override
public <T> void visitCtUnaryOperator(CtUnaryOperator<T> operator) {
for (CtVariableAccess a : accessOfExpression(operator)) {
// Add cyclic dependencies to external variables
if (declaredInsideBlock.contains(a.getVariable())) {
remove(operator);
return;
}
}
}
@Override
public <T, A extends T> void visitCtOperatorAssignement(CtOperatorAssignment<T, A> assignment) {
for (CtVariableAccess a : accessOfExpression(assignment.getAssigned())) {
// Add cyclic dependencies
if (!declaredInsideBlock.contains(a.getVariable())) {
remove(assignment);
return;
}
}
}
/**
* Indicates that contains operation assignment over variables non local to the element
*
* @param element
* @return
*/
private boolean containNonLocalOperatorAssignment(CtElement element) {
// Handling operators assignment
for (CtOperatorAssignment op :
element.getElements(new TypeFilter<CtOperatorAssignment>(CtOperatorAssignment.class))) {
for (CtVariableAccess a : accessOfExpression(op.getAssigned())) {
// Add cyclic dependencies
if (!declaredInsideBlock.contains(a.getVariable())) return true;
}
}
return false;
}
/**
* Indicates if the element contains unary operators acting on variables declared outside the
* block being degraded
*
* @param element Element to inspect
* @return True if contains
*/
private boolean containsNonLocalUnaryOperators(CtElement element) {
// Handling unary operators
for (CtUnaryOperator op :
element.getElements(new TypeFilter<CtUnaryOperator>(CtUnaryOperator.class))) {
for (CtVariableAccess a : accessOfExpression(op)) {
// We don't care about cyclic dependencies to vars declared inside the block being degraded
if (!declaredInsideBlock.contains(a.getVariable())) return true;
}
}
return false;
}
/**
* Indicate if the statement contains a mutable expression
*
* <p>A mutability expression is an expression that assigns value to a variable in the left side
* using that variable also in the right side, like this:
*
* <p>a = a * b
*
* <p>or like this: c = a * 2 a = c + b
*
* <p>
*
* <p>Also, all unary operators and are mutable: a--; a++;
*
* @param statement Statement to check whether is a mutability expression
* @return True if it is a mutability expression
*/
private Mutability mutability(CtElement statement) {
Mutability result = Mutability.ERASABLE;
if (statement instanceof CtAssignment) {
CtAssignment e = (CtAssignment) statement;
List<CtVariableAccess> left = accessOfLeftExpression(e.getAssigned());
for (CtVariableAccess access : left) {
CtVariableReference ref = access.getVariable();
try {
if (!declaredInsideBlock.contains(ref)
&& cycleDetector.detectCyclesContainingVertex(ref)) {
return Mutability.IMMUTABLE;
}
} catch (IllegalArgumentException ex) {
continue;
}
}
}
if (containNonLocalOperatorAssignment(statement)) return Mutability.IMMUTABLE;
else if (containsNonLocalUnaryOperators(statement)) return Mutability.REPLACEABLE;
else return Mutability.ERASABLE;
}