internal static bool AssignsValueToBackingField(AccessorDeclarationSyntax setter, out AssignmentExpressionSyntax assignment)
{
using (var pooled = AssignmentWalker.Create(setter))
{
foreach (var a in pooled.Item.Assignments)
{
if ((a.Right as IdentifierNameSyntax)?.Identifier.ValueText != "value")
{
continue;
}
if (a.Left is IdentifierNameSyntax)
{
assignment = a;
return(true);
}
var memberAccess = a.Left as MemberAccessExpressionSyntax;
if (memberAccess?.Expression is ThisExpressionSyntax &&
memberAccess.Name is IdentifierNameSyntax)
{
assignment = a;
return(true);
}
}
}
assignment = null;
return(false);
}
internal static bool TryGetBackingField(PropertyDeclarationSyntax property, out IdentifierNameSyntax field, out FieldDeclarationSyntax fieldDeclaration)
{
field = null;
fieldDeclaration = null;
if (property == null)
{
return(false);
}
AccessorDeclarationSyntax setter;
if (property.TryGetSetAccessorDeclaration(out setter) &&
setter.Body != null)
{
using (var pooled = AssignmentWalker.Create(setter))
{
if (pooled.Item.Assignments.Count != 1)
{
return(false);
}
var left = pooled.Item.Assignments[0].Left;
field = left as IdentifierNameSyntax;
if (field == null)
{
var memberAccess = left as MemberAccessExpressionSyntax;
if (!(memberAccess?.Expression is ThisExpressionSyntax))
{
return(false);
}
field = memberAccess.Name as IdentifierNameSyntax;
}
if (field == null)
{
return(false);
}
foreach (var member in property.FirstAncestorOrSelf <TypeDeclarationSyntax>().Members)
{
fieldDeclaration = member as FieldDeclarationSyntax;
if (fieldDeclaration != null)
{
foreach (var variable in fieldDeclaration.Declaration.Variables)
{
if (variable.Identifier.ValueText == field.Identifier.ValueText)
{
return(true);
}
}
}
}
}
}
return(false);
}
internal static bool IsLazy(this PropertyDeclarationSyntax propertyDeclaration, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (propertyDeclaration.TryGetSetAccessorDeclaration(out AccessorDeclarationSyntax _))
{
return(false);
}
IFieldSymbol returnedField = null;
if (propertyDeclaration.TryGetGetAccessorDeclaration(out AccessorDeclarationSyntax getter))
{
if (getter.Body == null)
{
return(false);
}
using (var pooledReturns = ReturnExpressionsWalker.Create(getter.Body))
{
if (pooledReturns.Item.ReturnValues.Count == 0)
{
return(false);
}
foreach (var returnValue in pooledReturns.Item.ReturnValues)
{
var returnedSymbol = returnValue?.IsKind(SyntaxKind.CoalesceExpression) == true
? semanticModel.GetSymbolSafe((returnValue as BinaryExpressionSyntax)?.Left, cancellationToken) as IFieldSymbol
: semanticModel.GetSymbolSafe(returnValue, cancellationToken) as IFieldSymbol;
if (returnedSymbol == null)
{
return(false);
}
if (returnedField != null &&
!ReferenceEquals(returnedSymbol, returnedField))
{
return(false);
}
returnedField = returnedSymbol;
}
}
return(AssignmentWalker.Assigns(returnedField, getter.Body, semanticModel, cancellationToken));
}
var arrow = propertyDeclaration.ExpressionBody;
if (arrow?.Expression?.IsKind(SyntaxKind.CoalesceExpression) != true)
{
return(false);
}
returnedField = semanticModel.GetSymbolSafe((arrow.Expression as BinaryExpressionSyntax)?.Left, cancellationToken) as IFieldSymbol;
return(AssignmentWalker.Assigns(returnedField, arrow.Expression, semanticModel, cancellationToken));
}