private AttributeListSyntax BuildUnmanagedFunctionPointerAttribute(DllImportData dllImportData)
{
var charset = string.Format("CharSet = CharSet.{0}", dllImportData.CharacterSet);
var charsetArgument = Syntax.AttributeArgument(Syntax.ParseExpression(charset));
var setLastError = string.Format("SetLastError = {0}", dllImportData.SetLastError.ToProperString());
var setLastErrorArgument = Syntax.AttributeArgument(Syntax.ParseExpression(setLastError));
var callingConvention = string.Format("CallingConvention.{0}", dllImportData.CallingConvention);
var callingConventionArgument = Syntax.AttributeArgument(Syntax.ParseExpression(callingConvention));
var arguments = Syntax.SeparatedList(callingConventionArgument).Add(setLastErrorArgument, charsetArgument);
if (dllImportData.BestFitMapping.HasValue)
{
var bestFitMapping = string.Format("BestFitMapping = {0}", dllImportData.BestFitMapping.ToProperString());
var bestFitMappingArgument = Syntax.AttributeArgument(Syntax.ParseExpression(bestFitMapping));
arguments = arguments.Add(bestFitMappingArgument);
}
if (dllImportData.ThrowOnUnmappableCharacter.HasValue)
{
var throwOnUnmappableCharacter = string.Format("ThrowOnUnmappableChar = {0}", dllImportData.ThrowOnUnmappableCharacter.ToProperString());
var throwOnUnmappableCharacterArgument = Syntax.AttributeArgument(Syntax.ParseExpression(throwOnUnmappableCharacter));
arguments = arguments.Add(throwOnUnmappableCharacterArgument);
}
var unmanagedFunctionPointerAttribute = Syntax.Attribute(Syntax.ParseName("UnmanagedFunctionPointer"))
.WithArgumentList(Syntax.AttributeArgumentList(arguments));
return Syntax.AttributeList(Syntax.SeparatedList(unmanagedFunctionPointerAttribute));
}
public void AnalyzeSymbol(SymbolAnalysisContext context)
{
var methodSymbol = (IMethodSymbol)context.Symbol;
if (methodSymbol == null)
{
return;
}
DllImportData dllImportData = methodSymbol.GetDllImportData();
if (dllImportData == null)
{
return;
}
AttributeData dllAttribute = methodSymbol.GetAttributes().FirstOrDefault(attr => attr.AttributeClass.Equals(_dllImportType));
Location defaultLocation = dllAttribute == null?methodSymbol.Locations.FirstOrDefault() : GetAttributeLocation(dllAttribute);
// CA1401 - PInvoke methods should not be visible
if (methodSymbol.GetResultantVisibility() == SymbolVisibility.Public)
{
context.ReportDiagnostic(context.Symbol.CreateDiagnostic(RuleCA1401, methodSymbol.Name));
}
// CA2101 - Specify marshalling for PInvoke string arguments
if (dllImportData.BestFitMapping != false)
{
bool appliedCA2101ToMethod = false;
foreach (IParameterSymbol parameter in methodSymbol.Parameters)
{
if (parameter.Type.SpecialType == SpecialType.System_String || parameter.Type.Equals(_stringBuilderType))
{
AttributeData marshalAsAttribute = parameter.GetAttributes().FirstOrDefault(attr => attr.AttributeClass.Equals(_marshalAsType));
CharSet? charSet = marshalAsAttribute == null
? dllImportData.CharacterSet
: MarshalingToCharSet(GetParameterMarshaling(marshalAsAttribute));
// only unicode marshaling is considered safe
if (charSet != CharSet.Unicode)
{
if (marshalAsAttribute != null)
{
// track the diagnostic on the [MarshalAs] attribute
Location marshalAsLocation = GetAttributeLocation(marshalAsAttribute);
context.ReportDiagnostic(Diagnostic.Create(RuleCA2101, marshalAsLocation));
}
else if (!appliedCA2101ToMethod)
{
// track the diagnostic on the [DllImport] attribute
appliedCA2101ToMethod = true;
context.ReportDiagnostic(Diagnostic.Create(RuleCA2101, defaultLocation));
}
}
}
}
// only unicode marshaling is considered safe, but only check this if we haven't already flagged the attribute
if (!appliedCA2101ToMethod && dllImportData.CharacterSet != CharSet.Unicode &&
(methodSymbol.ReturnType.SpecialType == SpecialType.System_String || methodSymbol.ReturnType.Equals(_stringBuilderType)))
{
context.ReportDiagnostic(Diagnostic.Create(RuleCA2101, defaultLocation));
}
}
}
