private static void AnalyzeSimpleMemberAccessExpression(SyntaxNodeAnalysisContext context)
{
var memberAccess = (MemberAccessExpressionSyntax)context.Node;
if (memberAccess.IsParentKind(SyntaxKind.SimpleMemberAccessExpression))
{
return;
}
if (memberAccess.Expression == null)
{
return;
}
if (memberAccess.Name?.Identifier.ValueText != "Empty")
{
return;
}
var fieldSymbol = context.SemanticModel.GetSymbol(memberAccess.Name, context.CancellationToken) as IFieldSymbol;
if (!SymbolUtility.IsPublicStaticReadOnly(fieldSymbol))
{
return;
}
if (fieldSymbol.ContainingType?.SpecialType != SpecialType.System_String)
{
return;
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticRules.UseEmptyStringLiteralInsteadOfStringEmptyOrViceVersa, memberAccess, AnalyzerOptions.UseStringEmptyInsteadOfEmptyStringLiteral);
}
public static bool IsFixable(
MemberAccessExpressionSyntax memberAccess,
SemanticModel semanticModel,
CancellationToken cancellationToken = default)
{
if (memberAccess.IsParentKind(SyntaxKind.SimpleMemberAccessExpression))
{
return(false);
}
if (memberAccess.Expression == null)
{
return(false);
}
if (memberAccess.Name?.Identifier.ValueText != "Empty")
{
return(false);
}
var fieldSymbol = semanticModel.GetSymbol(memberAccess.Name, cancellationToken) as IFieldSymbol;
return(SymbolUtility.IsPublicStaticReadOnly(fieldSymbol) &&
fieldSymbol.ContainingType?.SpecialType == SpecialType.System_String);
}
public static bool IsEmptyStringExpression(
ExpressionSyntax expression,
SemanticModel semanticModel,
CancellationToken cancellationToken = default(CancellationToken))
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
if (semanticModel == null)
{
throw new ArgumentNullException(nameof(semanticModel));
}
SyntaxKind kind = expression.Kind();
if (kind == SyntaxKind.StringLiteralExpression)
{
return(((LiteralExpressionSyntax)expression).Token.ValueText.Length == 0);
}
else if (kind == SyntaxKind.InterpolatedStringExpression)
{
return(!((InterpolatedStringExpressionSyntax)expression).Contents.Any());
}
else if (kind == SyntaxKind.SimpleMemberAccessExpression)
{
var memberAccess = (MemberAccessExpressionSyntax)expression;
if (memberAccess.Name?.Identifier.ValueText == "Empty")
{
ISymbol symbol = semanticModel.GetSymbol(memberAccess, cancellationToken);
if (symbol?.Kind == SymbolKind.Field)
{
var fieldSymbol = (IFieldSymbol)symbol;
if (SymbolUtility.IsPublicStaticReadOnly(fieldSymbol, "Empty") &&
fieldSymbol.ContainingType?.SpecialType == SpecialType.System_String &&
fieldSymbol.Type.IsString())
{
return(true);
}
}
}
}
Optional <object> optional = semanticModel.GetConstantValue(expression, cancellationToken);
if (optional.HasValue)
{
var value = optional.Value as string;
return(value?.Length == 0);
}
return(false);
}