// Returning an array directly so that the enumeration in
// UserDefinedConversion does not allocate memory
private static MethodInfo[] GetUserDefinedConversionMethods(Type source, Type destination)
{
var query = new ConversionQuery(source, destination);
if (!userConversionMethodsCache.ContainsKey(query))
{
userConversionMethodsCache.Add(query, FindUserDefinedConversionMethods(query).ToArray());
}
return(userConversionMethodsCache[query]);
}
public static ConversionType GetRequiredConversion(Type source, Type destination)
{
var query = new ConversionQuery(source, destination);
if (!conversionTypesCache.TryGetValue(query, out var conversionType))
{
conversionType = DetermineConversionType(query);
conversionTypesCache.Add(query, conversionType);
}
return(conversionType);
}
private static IEnumerable <MethodInfo> FindUserDefinedConversionMethods(ConversionQuery query)
{
var source = query.source;
var destination = query.destination;
var sourceMethods = source.GetMethods(UserDefinedBindingFlags)
.Where(m => m.IsUserDefinedConversion());
var destinationMethods = destination.GetMethods(UserDefinedBindingFlags)
.Where(m => m.IsUserDefinedConversion());
return(sourceMethods.Concat(destinationMethods).Where
(
m => m.GetParameters()[0].ParameterType.IsAssignableFrom(source) ||
source.IsAssignableFrom(m.GetParameters()[0].ParameterType)
));
}
private static ConversionType DetermineConversionType(ConversionQuery query)
{
var source = query.source;
var destination = query.destination;
if (source == null)
{
if (destination.IsNullable())
{
return(ConversionType.Identity);
}
else
{
return(ConversionType.Impossible);
}
}
Ensure.That(nameof(destination)).IsNotNull(destination);
if (RespectsIdentity(source, destination))
{
return(ConversionType.Identity);
}
else if (IsUpcast(source, destination))
{
return(ConversionType.Upcast);
}
else if (IsDowncast(source, destination))
{
return(ConversionType.Downcast);
}
// Disabling *.ToString conversion, because it's more often than otherwise very confusing
/*else if (ExpectsString(source, destination))
* {
* return ConversionType.ToString;
* }*/
else if (HasImplicitNumericConversion(source, destination))
{
return(ConversionType.NumericImplicit);
}
else if (HasExplicitNumericConversion(source, destination))
{
return(ConversionType.NumericExplicit);
}
else if (HasUnityHierarchyConversion(source, destination))
{
return(ConversionType.UnityHierarchy);
}
else if (HasEnumerableToArrayConversion(source, destination))
{
return(ConversionType.EnumerableToArray);
}
else if (HasEnumerableToListConversion(source, destination))
{
return(ConversionType.EnumerableToList);
}
else
{
var userDefinedConversionType = GetUserDefinedConversionType(source, destination);
if (userDefinedConversionType != ConversionType.Impossible)
{
return(userDefinedConversionType);
}
}
return(ConversionType.Impossible);
}
