public override void VisitObjectCreationExpression(ObjectCreationExpressionSyntax node)
{
CheckThrowKeyword(node);
foreach (var n in node.ChildNodes())
{
Visit(n);
}
}
private Task <Document> UseNewGuid(Document document, SyntaxNode root, ObjectCreationExpressionSyntax statement)
{
// We're not adding the simplifier in this route because it doesn't seem to work
// It works when putting it on the root node but that has too many consequences for other code
// We do some simple introspection to see if it is fully qualified already or not
var newExpression = "Guid.NewGuid()";
if (statement.ChildNodes().First().IsKind(SyntaxKind.QualifiedName))
{
newExpression = "System.Guid.NewGuid()";
}
var newRoot = root.ReplaceNode(statement, SyntaxFactory.ParseExpression(newExpression));
return(Task.FromResult(document.WithSyntaxRoot(newRoot)));
}
/* Method that checks whether or not Singleton class is thread safe
* by way of double check locking
*/
public bool IsDoubleCheckLocked(ClassDeclarationSyntax classDec)
{
/* List of methods that might be used to
* return instances of singleton class
*/
List <MethodDeclarationSyntax> possibleInstanceMethods =
new List <MethodDeclarationSyntax>();
// Get List of all methodDeclarations in class
List <MethodDeclarationSyntax> methodDeclarations =
classDec.DescendantNodes().
OfType <MethodDeclarationSyntax>().ToList();
bool classContainsValidMethod = false;
foreach (MethodDeclarationSyntax methodDec in methodDeclarations)
{
bool isPublic = false;
bool isStatic = false;
/* Check if method returns an instance of class first,
* otherwise don't do more taxing operations
*/
if (methodDec.ReturnType.ToString().
Equals(classDec.Identifier.Text))
{
/* Check whether or not method is public and static,
* both of which instance method should be
*/
SyntaxTokenList modifiers = methodDec.Modifiers;
foreach (SyntaxToken modifier in modifiers)
{
if (modifier.IsKind(SyntaxKind.PublicKeyword))
{
isPublic = true;
}
else if (modifier.IsKind(SyntaxKind.StaticKeyword))
{
isStatic = true;
}
}
}
/* isPublic and isStatic can only have been changed to true
* if returnType is correct. If conditions are fulfilled,
* add checked method to list of possible instance methods
*/
if (isPublic && isStatic)
{
possibleInstanceMethods.Add(methodDec);
}
}
foreach (
MethodDeclarationSyntax methodDec in
possibleInstanceMethods)
{
/* Can choose .First() because method can
* syntactically only have one Block
*/
BlockSyntax block = methodDec.ChildNodes().
OfType <BlockSyntax>().First();
string identifier = "";
bool containsFirstCheck = false;
List <SyntaxNode> nodes =
block.ChildNodes().OfType <SyntaxNode>().ToList();
BlockSyntax secondBlock = null;
foreach (SyntaxNode node in nodes)
{
/* Check whether or not the block contains an if-stmt
* that checks the instance variable for null
*/
if (node.IsKind(SyntaxKind.IfStatement))
{
List <SyntaxNodeOrToken> subNodes =
node.ChildNodesAndTokens().
OfType <SyntaxNodeOrToken>().ToList();
bool isEqualsEquals = false;
bool checksForNull = false;
foreach (SyntaxNodeOrToken subNode in subNodes)
{
if (subNode.IsKind(SyntaxKind.EqualsExpression))
{
List <SyntaxNodeOrToken> subSubNodes =
subNode.ChildNodesAndTokens().
OfType <SyntaxNodeOrToken>().ToList();
foreach (
SyntaxNodeOrToken subSubNode in
subSubNodes)
{
if (subSubNode.IsKind(
SyntaxKind.IdentifierName))
{
identifier = subSubNode.ToString();
}
else if (subSubNode.IsKind(
SyntaxKind.EqualsEqualsToken))
{
isEqualsEquals = true;
}
else if (subSubNode.IsKind(
SyntaxKind.NullLiteralExpression))
{
checksForNull = true;
}
}
}
}
if (isEqualsEquals && checksForNull)
{
containsFirstCheck = true;
secondBlock = node.ChildNodes().
OfType <BlockSyntax>().First();
}
}
}
bool containsLock = false;
BlockSyntax thirdBlock = null;
/* If instance variable is checked for null first,
* check if after that check, a lock occurs
*/
if (containsFirstCheck)
{
List <SyntaxNode> subNodes =
secondBlock.ChildNodes().OfType <SyntaxNode>().ToList();
foreach (SyntaxNode subNode in subNodes)
{
if (subNode.IsKind(SyntaxKind.LockStatement))
{
containsLock = true;
thirdBlock = subNode.ChildNodes().
OfType <BlockSyntax>().First();
}
}
}
bool containsSecondCheck = false;
BlockSyntax fourthBlock = null;
/* If the lock occurs, check if another
* null-check on instance variable happens
*/
if (containsLock)
{
List <SyntaxNode> subNodes =
thirdBlock.ChildNodes().
OfType <SyntaxNode>().ToList();
foreach (SyntaxNode subNode in subNodes)
{
if (subNode.IsKind(
SyntaxKind.IfStatement))
{
List <SyntaxNode> subSubNodes =
subNode.ChildNodes().
OfType <SyntaxNode>().ToList();
foreach (SyntaxNode subSubNode in subSubNodes)
{
if (subSubNode.IsKind(
SyntaxKind.EqualsExpression))
{
List <SyntaxNodeOrToken> subSubSubNodes =
subSubNode.ChildNodesAndTokens().
OfType <SyntaxNodeOrToken>().ToList();
bool correctIdentifier = false;
bool isEqualsEquals = false;
bool checksForNull = false;
foreach (
SyntaxNodeOrToken subSubSubNode in
subSubSubNodes)
{
if (subSubSubNode.IsKind(
SyntaxKind.IdentifierName) &&
subSubSubNode.ToString() ==
identifier)
{
correctIdentifier = true;
}
else if (subSubSubNode.IsKind(
SyntaxKind.EqualsEqualsToken))
{
isEqualsEquals = true;
}
else if (subSubSubNode.IsKind(
SyntaxKind.NullLiteralExpression))
{
checksForNull = true;
}
}
if (correctIdentifier &&
isEqualsEquals &&
checksForNull)
{
containsSecondCheck = true;
fourthBlock = subNode.ChildNodes().
OfType <BlockSyntax>().First();
}
}
}
}
}
}
bool isValidDoubleCheck = false;
/* If second null-check happens, finally check whether or not
* after that second null-check, a value is assigned to
* the instance variable of type {ClassName}
* in which case it can be determined that a valid
* double check lock has occured
*/
if (containsSecondCheck)
{
List <SyntaxNode> subNodes =
fourthBlock.ChildNodes().
OfType <SyntaxNode>().ToList();
foreach (SyntaxNode subNode in subNodes)
{
if (subNode.IsKind(SyntaxKind.ExpressionStatement))
{
List <SyntaxNode> subSubNodes =
subNode.ChildNodes().
OfType <SyntaxNode>().ToList();
foreach (SyntaxNode subSubNode in subSubNodes)
{
if (subSubNode.IsKind
(SyntaxKind.SimpleAssignmentExpression))
{
/* SimpleAssignmentExpression can
* only have an identifier name
*/
if (subSubNode.ChildNodes().
OfType <IdentifierNameSyntax>().
First().Identifier.Text == identifier)
{
/* Only one ObjectCreationExpression
* can be attached to a
* SimpleAssignmentExpression
*/
ObjectCreationExpressionSyntax
objectCreationExp =
subSubNode.ChildNodes().
OfType <ObjectCreationExpressionSyntax>().
First();
/* ObjectCreationExpression can only
* have one IdentifierName
* attached to it
*/
if (objectCreationExp.ChildNodes().
OfType <IdentifierNameSyntax>().
First().Identifier.Text ==
classDec.Identifier.Text)
{
isValidDoubleCheck = true;
}
}
}
}
}
}
if (isValidDoubleCheck)
{
classContainsValidMethod = true;
}
}
}
return(classContainsValidMethod);
}
