/// <summary>
/// Initializes a new instance of the <see cref="JsonMigrationContext"/> structure. This is an internal method.
/// </summary>
/// <param name="serializedVersion">The serialized version read from the stream.</param>
/// <param name="serializedObject">The view over the serialized data.</param>
/// <param name="serializedType">The serialized type from the stream.</param>
/// <param name="visitor">The current deserialization visitor, used for re-entry into normal deserialization.</param>
internal JsonMigrationContext(int serializedVersion, SerializedObjectView serializedObject, Type serializedType, JsonPropertyReader visitor)
{
SerializedVersion = serializedVersion;
SerializedObject = serializedObject;
SerializedType = serializedType;
m_Visitor = visitor;
}
public bool TryMigrate <TValue>(UnsafeObjectView view, out TValue value, JsonPropertyReader reader, List <DeserializationEvent> events)
{
var migration = GetMigrationForType <TValue>(out var version);
if (null == migration)
{
value = default;
return(false);
}
var serializedVersion = 0;
if (view.TryGetValue(JsonPropertyVisitor.k_SerializedVersionKey, out var serializedVersionView))
{
if (serializedVersionView.Type != TokenType.Primitive)
{
events.Add(new DeserializationEvent(EventType.Exception, new Exception($"An error occured while deserializing Type=[{typeof(TValue)}]. Property=[{JsonPropertyVisitor.k_SerializedVersionKey}] is expected to be an int value.")));
value = default;
return(false);
}
serializedVersion = serializedVersionView.AsInt32();
if (version == serializedVersion)
{
value = default;
return(false);
}
}
var context = new JsonMigrationContext(serializedVersion, view.AsSafe(), typeof(TValue), UserData, reader);
switch (migration)
{
case IJsonMigration <TValue> typed:
value = typed.Migrate(context);
break;
case Contravariant.IJsonMigration <TValue> typedContravariant:
value = (TValue)typedContravariant.Migrate(context);
break;
default:
throw new Exception("An internal error has occured.");
}
return(true);
}
