@Override
public void visitLiteralExpression(@NotNull PsiLiteralExpression value) {
super.visitLiteralExpression(value);
final String text = value.getText();
if (!PsiKeyword.NULL.equals(text)) {
return;
}
PsiElement parent = value.getParent();
while (parent instanceof PsiParenthesizedExpression
|| parent instanceof PsiConditionalExpression
|| parent instanceof PsiTypeCastExpression) {
parent = parent.getParent();
}
if (parent == null || !(parent instanceof PsiReturnStatement)) {
return;
}
final PsiMethod method = PsiTreeUtil.getParentOfType(value, PsiMethod.class);
if (method == null) {
return;
}
final PsiType returnType = method.getReturnType();
if (returnType == null) {
return;
}
final boolean isArray = returnType.getArrayDimensions() > 0;
if (AnnotationUtil.isAnnotated(method, AnnotationUtil.NULLABLE, false)) {
return;
}
if (m_reportCollectionMethods && CollectionUtils.isCollectionClassOrInterface(returnType)) {
registerError(value, value);
} else if (m_reportArrayMethods && isArray) {
registerError(value, value);
} else if (m_reportObjectMethods && !isArray) {
registerError(value, value);
}
}
private boolean checkCondition(
@Nullable PsiExpression condition,
@NotNull PsiStatement context,
List<PsiExpression> notUpdated) {
if (condition == null) {
return false;
}
if (PsiUtil.isConstantExpression(condition) || PsiKeyword.NULL.equals(condition.getText())) {
return true;
}
if (condition instanceof PsiInstanceOfExpression) {
final PsiInstanceOfExpression instanceOfExpression = (PsiInstanceOfExpression) condition;
final PsiExpression operand = instanceOfExpression.getOperand();
return checkCondition(operand, context, notUpdated);
} else if (condition instanceof PsiParenthesizedExpression) {
// catch stuff like "while ((x)) { ... }"
final PsiExpression expression = ((PsiParenthesizedExpression) condition).getExpression();
return checkCondition(expression, context, notUpdated);
} else if (condition instanceof PsiPolyadicExpression) {
// while (value != x) { ... }
// while (value != (x + y)) { ... }
// while (b1 && b2) { ... }
final PsiPolyadicExpression polyadicExpression = (PsiPolyadicExpression) condition;
for (PsiExpression operand : polyadicExpression.getOperands()) {
if (!checkCondition(operand, context, notUpdated)) {
return false;
}
}
return true;
} else if (condition instanceof PsiReferenceExpression) {
final PsiReferenceExpression referenceExpression = (PsiReferenceExpression) condition;
final PsiElement element = referenceExpression.resolve();
if (element instanceof PsiField) {
final PsiField field = (PsiField) element;
final PsiType type = field.getType();
if (field.hasModifierProperty(PsiModifier.FINAL) && type.getArrayDimensions() == 0) {
if (field.hasModifierProperty(PsiModifier.STATIC)) {
return true;
}
final PsiExpression qualifier = referenceExpression.getQualifierExpression();
if (qualifier == null) {
return true;
} else if (checkCondition(qualifier, context, notUpdated)) {
return true;
}
}
} else if (element instanceof PsiVariable) {
final PsiVariable variable = (PsiVariable) element;
if (variable.hasModifierProperty(PsiModifier.FINAL)) {
// final variables cannot be updated, don't bother to
// flag them
return true;
} else if (element instanceof PsiLocalVariable || element instanceof PsiParameter) {
if (!VariableAccessUtils.variableIsAssigned(variable, context)) {
notUpdated.add(referenceExpression);
return true;
}
}
}
} else if (condition instanceof PsiPrefixExpression) {
final PsiPrefixExpression prefixExpression = (PsiPrefixExpression) condition;
final IElementType tokenType = prefixExpression.getOperationTokenType();
if (JavaTokenType.EXCL.equals(tokenType)
|| JavaTokenType.PLUS.equals(tokenType)
|| JavaTokenType.MINUS.equals(tokenType)) {
final PsiExpression operand = prefixExpression.getOperand();
return checkCondition(operand, context, notUpdated);
}
} else if (condition instanceof PsiArrayAccessExpression) {
// Actually the contents of the array could change nevertheless
// if it is accessed through a different reference like this:
// int[] local_ints = new int[]{1, 2};
// int[] other_ints = local_ints;
// while (local_ints[0] > 0) { other_ints[0]--; }
//
// Keep this check?
final PsiArrayAccessExpression accessExpression = (PsiArrayAccessExpression) condition;
final PsiExpression indexExpression = accessExpression.getIndexExpression();
return checkCondition(indexExpression, context, notUpdated)
&& checkCondition(accessExpression.getArrayExpression(), context, notUpdated);
} else if (condition instanceof PsiConditionalExpression) {
final PsiConditionalExpression conditionalExpression = (PsiConditionalExpression) condition;
final PsiExpression thenExpression = conditionalExpression.getThenExpression();
final PsiExpression elseExpression = conditionalExpression.getElseExpression();
if (thenExpression == null || elseExpression == null) {
return false;
}
return checkCondition(conditionalExpression.getCondition(), context, notUpdated)
&& checkCondition(thenExpression, context, notUpdated)
&& checkCondition(elseExpression, context, notUpdated);
} else if (condition instanceof PsiThisExpression) {
return true;
} else if (condition instanceof PsiMethodCallExpression && !ignoreIterators) {
final PsiMethodCallExpression methodCallExpression = (PsiMethodCallExpression) condition;
if (!IteratorUtils.isCallToHasNext(methodCallExpression)) {
return false;
}
final PsiReferenceExpression methodExpression = methodCallExpression.getMethodExpression();
final PsiExpression qualifierExpression = methodExpression.getQualifierExpression();
if (qualifierExpression instanceof PsiReferenceExpression) {
final PsiReferenceExpression referenceExpression =
(PsiReferenceExpression) qualifierExpression;
final PsiElement element = referenceExpression.resolve();
if (!(element instanceof PsiVariable)) {
return false;
}
final PsiVariable variable = (PsiVariable) element;
if (!IteratorUtils.containsCallToScannerNext(context, variable, true)) {
notUpdated.add(qualifierExpression);
return true;
}
} else {
if (!IteratorUtils.containsCallToScannerNext(context, null, true)) {
notUpdated.add(methodCallExpression);
return true;
}
}
}
return false;
}