protected sealed override Guid?ComputeGuidFromCustomAttributes()
{
//
// Look for a [Guid] attribute. If found, return that.
//
foreach (CustomAttributeHandle cah in _typeDefinition.CustomAttributes)
{
// We can't reference the GuidAttribute class directly as we don't have an official dependency on System.Runtime.InteropServices.
// Following age-old CLR tradition, we search for the custom attribute using a name-based search. Since this makes it harder
// to be sure we won't run into custom attribute constructors that comply with the GuidAttribute(String) signature,
// we'll check that it does and silently skip the CA if it doesn't match the expected pattern.
if (cah.IsCustomAttributeOfType(_reader, "System.Runtime.InteropServices", "GuidAttribute"))
{
CustomAttribute ca = cah.GetCustomAttribute(_reader);
FixedArgumentHandleCollection.Enumerator fahEnumerator = ca.FixedArguments.GetEnumerator();
if (!fahEnumerator.MoveNext())
{
continue;
}
FixedArgumentHandle guidStringArgumentHandle = fahEnumerator.Current;
if (fahEnumerator.MoveNext())
{
continue;
}
FixedArgument guidStringArgument = guidStringArgumentHandle.GetFixedArgument(_reader);
if (!(guidStringArgument.Value.ParseConstantValue(_reader) is string guidString))
{
continue;
}
return(new Guid(guidString));
}
}
return(null);
}
// Equals/GetHashCode no need to override (they just implement reference equality but desktop never unified these things.)
//
// Helper for parsing custom attribute arguments.
//
// If throwIfMissingMetadata is false, returns default(CustomAttributeTypedArgument) rather than throwing a MissingMetadataException.
//
private CustomAttributeTypedArgument ParseFixedArgument(MetadataReader reader, FixedArgumentHandle fixedArgumentHandle, bool throwIfMissingMetadata, Func <RuntimeTypeInfo> getTypeFromConstructor)
{
FixedArgument fixedArgument = fixedArgumentHandle.GetFixedArgument(reader);
RuntimeTypeInfo argumentType = null;
if (fixedArgument.Type.IsNull(reader))
{
argumentType = getTypeFromConstructor();
if (argumentType == null)
{
Debug.Assert(!throwIfMissingMetadata);
return(default(CustomAttributeTypedArgument));
}
}
else
{
Exception exception = null;
argumentType = fixedArgument.Type.TryResolve(reader, new TypeContext(null, null), ref exception);
if (argumentType == null)
{
if (throwIfMissingMetadata)
{
throw exception;
}
else
{
return(default(CustomAttributeTypedArgument));
}
}
}
Object value;
Exception e = fixedArgument.Value.TryParseConstantValue(reader, out value);
if (e != null)
{
if (throwIfMissingMetadata)
{
throw e;
}
else
{
return(default(CustomAttributeTypedArgument));
}
}
return(WrapInCustomAttributeTypedArgument(value, argumentType));
}
// Equals/GetHashCode no need to override (they just implement reference equality but desktop never unified these things.)
//
// Helper for parsing custom attribute arguments.
//
// If throwIfMissingMetadata is false, returns default(CustomAttributeTypedArgument) rather than throwing a MissingMetadataException.
//
private CustomAttributeTypedArgument ParseFixedArgument(MetadataReader reader, FixedArgumentHandle fixedArgumentHandle, bool throwIfMissingMetadata, Func<RuntimeType> getTypeFromConstructor)
{
FixedArgument fixedArgument = fixedArgumentHandle.GetFixedArgument(reader);
RuntimeType argumentType = null;
if (fixedArgument.Type.IsNull(reader))
{
argumentType = getTypeFromConstructor();
if (argumentType == null)
{
Debug.Assert(!throwIfMissingMetadata);
return default(CustomAttributeTypedArgument);
}
}
else
{
Exception exception = null;
argumentType = _reflectionDomain.TryResolve(reader, fixedArgument.Type, new TypeContext(null, null), ref exception);
if (argumentType == null)
{
if (throwIfMissingMetadata)
throw exception;
else
return default(CustomAttributeTypedArgument);
}
}
Object value;
Exception e = fixedArgument.Value.TryParseConstantValue(_reflectionDomain, reader, out value);
if (e != null)
{
if (throwIfMissingMetadata)
throw e;
else
return default(CustomAttributeTypedArgument);
}
return WrapInCustomAttributeTypedArgument(value, argumentType);
}