public object Deserialize(
BsonReader bsonReader,
Type classType
)
{
// peek at the discriminator (if present) to see what class to create an instance for
var discriminator = bsonReader.FindString("_t");
if (discriminator != null) {
var actualType = BsonClassMap.LookupTypeByDiscriminator(classType, discriminator);
if (!classType.IsAssignableFrom(actualType)) {
string message = string.Format("Actual type {0} is not assignable to expected type {1}", actualType.FullName, classType.FullName);
throw new FileFormatException(message);
}
classType = actualType;
}
var classMap = BsonClassMap.LookupClassMap(classType);
if (classMap.IsAnonymous) {
throw new InvalidOperationException("Anonymous classes cannot be deserialized");
}
var obj = Activator.CreateInstance(classType);
var missingElementPropertyMaps = new List<BsonPropertyMap>(classMap.PropertyMaps); // make a copy!
bsonReader.ReadStartDocument();
BsonType bsonType;
string elementName;
while (bsonReader.HasElement(out bsonType, out elementName)) {
if (elementName == "_t") {
bsonReader.ReadString("_t"); // skip over discriminator
continue;
}
var propertyMap = classMap.GetPropertyMapForElement(elementName);
if (propertyMap != null) {
propertyMap.PropertySerializer.DeserializeProperty(bsonReader, obj, propertyMap);
missingElementPropertyMaps.Remove(propertyMap);
} else {
if (classMap.IgnoreExtraElements) {
bsonReader.SkipElement();
} else {
string message = string.Format("Unexpected element: {0}", elementName);
throw new FileFormatException(message);
}
}
}
bsonReader.ReadEndDocument();
foreach (var propertyMap in missingElementPropertyMaps) {
if (propertyMap.IsRequired) {
string message = string.Format("Required element is missing: {0}", propertyMap.ElementName);
throw new BsonSerializationException(message);
}
if (propertyMap.HasDefaultValue) {
propertyMap.ApplyDefaultValue(obj);
}
}
return obj;
}