private static void BuildIdAccess(Type entityType,
ref MetadataStorage metadataStorage,
out Func <object, string> idGetAccessor,
out Action <object, string> idSetAccessor)
{
var idMember = GetIdMember(entityType);
if (idMember == null)
{
var ms = metadataStorage = metadataStorage ?? new MetadataStorage();
string GetIdFromMetadata(object entity)
{
return(ms.GetMetadata(entity).GetId());
}
void SetIdToMetadata(object entity, string id)
{
ms.GetMetadata(entity).SetId(id);
}
idGetAccessor = GetIdFromMetadata;
idSetAccessor = SetIdToMetadata;
return;
}
// We could theoretically allow setting id to an entity,
// but this will need support for transforming a stringified id back to its original representation.
idSetAccessor = null;
var idType = DataPropertyHelper.GetIdType(entityType);
var entityParameter = Expression.Parameter(typeof(object), "entity");
var convertedEntity = Expression.Convert(entityParameter, entityType);
var idAccess = default(Expression);
if (idMember.MemberType == MemberTypes.Method)
{
idAccess = Expression.Call(convertedEntity, (MethodInfo)idMember);
}
else if (idMember.MemberType == MemberTypes.Field || idMember.MemberType == MemberTypes.Property)
{
idAccess = Expression.MakeMemberAccess(convertedEntity, idMember);
}
var toStringMethod = idType.GetMethod(nameof(ToString), BindingFlags.Public | BindingFlags.Instance, Type.DefaultBinder, Type.EmptyTypes, null);
Assert(toStringMethod != null);
if (idAccess != null)
{
var toStringCall = Expression.Call(idAccess, toStringMethod);
idGetAccessor = Expression.Lambda <Func <object, string> >(toStringCall, entityParameter).Compile();
}
else
{
idGetAccessor = null;
}
}
private IInMemoryDatabase <TData> CreateTypedStore <TData>()
where TData : class
{
var dataType = typeof(TData);
var idType = DataPropertyHelper.GetIdType <TData>();
if (idType == null)
{
throw new Exception($"Cannot store objects of type '{typeof(TData).FullName}'. An id cannot be extracted."); // TODO
}
var typedStore = Activator.CreateInstance(typeof(InMemoryDatabase <,>).MakeGenericType(idType, dataType));
return((IInMemoryDatabase <TData>)typedStore);
}