public bool MapDestinationPropertyToSource(ProfileMap options, TypeDetails sourceType, Type destType, Type destMemberType, string nameToSearch, LinkedList <MemberInfo> resolvers, IMemberConfiguration parent)
{
if (TypeExtensions.IsAssignableFrom(typeof(IDataRecord), sourceType.Type))
{
var returnType = destMemberType;
// TODO: The return type really should be the type of the field in the reader.
// TODO: Remove the previous comment. We're going to add value conversion functionality, so using the destination
// type here can be done safely.
var method = new DynamicMethod($"Get{nameToSearch.Replace(".", string.Empty) }", returnType, new[] { typeof(IDataRecord) }, true);
var il = method.GetILGenerator();
EmitPropertyMapping(il, destType, destMemberType, nameToSearch);
il.Emit(Ret);
resolvers.AddLast(method);
return(true);
}
return(false);
}
private void EmitPropertyMapping(ILGenerator il, Type destType, Type destMemberType, string nameToSearch)
{
var returnType = destMemberType;
var fieldValueLocal = il.DeclareLocal(typeof(object));
var returnValueLocal = il.DeclareLocal(returnType);
var tryGetValueMethod = DataReaderHelper.TryGetValueMethod;
var dbNullElseLabel = il.DefineLabel();
var dbNullLabel = il.DefineLabel();
var endIfDbNullLabel = il.DefineLabel();
var getDbNullValueField = DataReaderHelper.DbNullValueField;
var underlyingType = Nullable.GetUnderlyingType(destMemberType);
var isNullable = (underlyingType != null);
// Call TryGetValue
il.Emit(Ldarg_0);
il.Emit(Ldstr, nameToSearch);
il.Emit(Ldloca_S, fieldValueLocal);
il.Emit(Call, tryGetValueMethod);
if (IsNestedObject(destMemberType))
{
var ctor = destMemberType.GetConstructor(Type.EmptyTypes);
if (ctor != null)
{
MethodInfo setMethod;
var objValueLocal = il.DeclareLocal(destMemberType);
var refersToMethod = DataReaderHelper.RefersToMethod;
var elseRefersToLabel = il.DefineLabel();
var endIfRefersToLabel = il.DefineLabel();
// If there are non-null fields referring to the nested property...
il.Emit(Ldarg_0);
il.Emit(Ldstr, nameToSearch);
il.Emit(Call, refersToMethod);
il.Emit(Brfalse, elseRefersToLabel);
il.Emit(Newobj, ctor);
il.Emit(Stloc, objValueLocal);
foreach (PropertyInfo property in TypeExtensions.GetProperties(destMemberType))
{
if (property.CanWrite)
{
setMethod = TypeExtensions.GetSetMethod(property, true);
il.Emit(Ldloc, objValueLocal);
EmitPropertyMapping(il, destMemberType, property.PropertyType, $"{nameToSearch}.{property.Name}");
il.Emit(Callvirt, setMethod);
}
}
il.Emit(Br, endIfRefersToLabel);
// else do this...
il.MarkLabel(elseRefersToLabel);
il.Emit(Ldnull);
il.Emit(Stloc, objValueLocal);
il.MarkLabel(endIfRefersToLabel);
il.Emit(Ldloc, objValueLocal);
il.Emit(Stloc, fieldValueLocal);
}
}
il.Emit(Pop);
// Test if field value == null
il.Emit(Ldloc, fieldValueLocal);
il.Emit(Ldnull);
il.Emit(Beq_S, dbNullLabel);
// Test if field value == DBNull (skipped when source field does not exist)
il.Emit(Ldloc, fieldValueLocal);
il.Emit(Ldsfld, getDbNullValueField);
il.Emit(Bne_Un_S, dbNullElseLabel);
// If so...
il.MarkLabel(dbNullLabel);
il.Emit(Ldloca_S, returnValueLocal);
il.Emit(Initobj, destMemberType);
il.Emit(Br_S, endIfDbNullLabel);
// else
il.MarkLabel(dbNullElseLabel);
il.Emit(Ldloc, fieldValueLocal);
if (isNullable)
{
var nullableCtor = destMemberType.GetConstructor(new[] { underlyingType });
il.Emit(Unbox_Any, underlyingType);
il.Emit(Newobj, nullableCtor);
}
else
{
il.Emit(Unbox_Any, destMemberType);
}
il.Emit(Stloc, returnValueLocal);
// end if
il.MarkLabel(endIfDbNullLabel);
// return
il.Emit(Ldloc, returnValueLocal);
}
