protected static IEnumerable <FieldInfo> GetFieldsWithAttribute <T>()
where T : Attribute
{
#if !UNITY_EDITOR || !UNITY_2020_1_OR_NEWER
foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
{
foreach (var type in assembly.GetTypes())
{
foreach (var field in type.GetFields(AllMemberFlags))
{
var attribute = field.GetCustomAttribute <T>();
if (attribute == null)
{
continue;
}
yield return(field);
}
}
}
#else
return(TypeCache.GetFieldsWithAttribute <T>());
#endif
}
protected void Cache <ItemType, Attr>()
where ItemType : MemberInfo
where Attr : Attribute
{
Type iType = typeof(ItemType);
Debug.Assert(typeof(FieldInfo).IsAssignableFrom(iType) ||
typeof(MethodInfo).IsAssignableFrom(iType));
if (typeof(FieldInfo).IsAssignableFrom(iType))
{
Cache <Attr>(
TypeCache.
GetFieldsWithAttribute <Attr>().
ToList()
);
}
else if (typeof(MethodInfo).IsAssignableFrom(iType))
{
Cache <Attr>(
TypeCache.
GetMethodsWithAttribute <Attr>().
ToList()
);
}
}
static IEnumerable <FieldInfo> GetFieldsWithAttribute <T>()
where T : Attribute
{
#if UNITY_2020_1_OR_NEWER
return(TypeCache.GetFieldsWithAttribute <T>());
#else
const BindingFlags AllMemberFlags = 0
| BindingFlags.Public | BindingFlags.NonPublic
| BindingFlags.Static | BindingFlags.Instance;
foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
{
foreach (var type in assembly.GetTypes())
{
foreach (var field in type.GetFields(AllMemberFlags))
{
var attribute = GetCustomAttribute <T>(field);
if (attribute == null)
{
continue;
}
yield return(field);
}
}
}
#endif
}
static void OnSubsystemRegistration()
{
foreach (FieldInfo field in TypeCache.GetFieldsWithAttribute <DefaultInitializeOnLoadAttribute>())
{
// Only static fields can be marked with [DefaultInitializeOnLoad]. There is unfortunately no way to
// specify that the compiler should validate this statically, so should we display an error for usages
// of the attribute on non-static fields?
if (field.IsStatic)
{
if (field.FieldType.IsValueType)
{
field.SetValue(null, Activator.CreateInstance(field.FieldType));
}
else
{
field.SetValue(null, null);
}
}
}
}
