public object Deserialize(
BsonReader bsonReader,
Type nominalType,
Type actualType,
IBsonSerializationOptions options)
{
VerifyNominalType(nominalType);
var bsonType = bsonReader.GetCurrentBsonType();
if (bsonType == Bson.BsonType.Null)
{
bsonReader.ReadNull();
return null;
}
else
{
if (actualType != _classMap.ClassType)
{
var message = string.Format("BsonClassMapSerializer.Deserialize for type {0} was called with actualType {1}.",
BsonUtils.GetFriendlyTypeName(_classMap.ClassType), BsonUtils.GetFriendlyTypeName(actualType));
throw new BsonSerializationException(message);
}
if (actualType.IsValueType)
{
var message = string.Format("Value class {0} cannot be deserialized.", actualType.FullName);
throw new BsonSerializationException(message);
}
if (_classMap.IsAnonymous)
{
throw new InvalidOperationException("An anonymous class cannot be deserialized.");
}
if (bsonType != BsonType.Document)
{
var message = string.Format(
"Expected a nested document representing the serialized form of a {0} value, but found a value of type {1} instead.",
actualType.FullName, bsonType);
throw new Exception(message);
}
Dictionary<string, object> values = null;
object obj = null;
ISupportInitialize supportsInitialization = null;
if (_classMap.HasCreatorMaps)
{
// for creator-based deserialization we first gather the values in a dictionary and then call a matching creator
values = new Dictionary<string, object>();
}
else
{
// for mutable classes we deserialize the values directly into the result object
obj = _classMap.CreateInstance();
supportsInitialization = obj as ISupportInitialize;
if (supportsInitialization != null)
{
supportsInitialization.BeginInit();
}
}
var discriminatorConvention = _classMap.GetDiscriminatorConvention();
var allMemberMaps = _classMap.AllMemberMaps;
var extraElementsMemberMapIndex = _classMap.ExtraElementsMemberMapIndex;
var memberMapBitArray = FastMemberMapHelper.GetBitArray(allMemberMaps.Count);
bsonReader.ReadStartDocument();
var elementTrie = _classMap.ElementTrie;
bool memberMapFound;
int memberMapIndex;
while (bsonReader.ReadBsonType(elementTrie, out memberMapFound, out memberMapIndex) != BsonType.EndOfDocument)
{
var elementName = bsonReader.ReadName();
if (memberMapFound)
{
var memberMap = allMemberMaps[memberMapIndex];
if (memberMapIndex != extraElementsMemberMapIndex)
{
if (obj != null)
{
if (memberMap.IsReadOnly)
{
bsonReader.SkipValue();
}
else
{
var value = DeserializeMemberValue(bsonReader, memberMap);
memberMap.Setter(obj, value);
}
}
else
{
var value = DeserializeMemberValue(bsonReader, memberMap);
values[elementName] = value;
}
}
else
{
DeserializeExtraElement(bsonReader, obj, elementName, memberMap);
}
memberMapBitArray[memberMapIndex >> 5] |= 1U << (memberMapIndex & 31);
}
else
{
if (elementName == discriminatorConvention.ElementName)
{
bsonReader.SkipValue(); // skip over discriminator
continue;
}
if (extraElementsMemberMapIndex >= 0)
{
DeserializeExtraElement(bsonReader, obj, elementName, _classMap.ExtraElementsMemberMap);
memberMapBitArray[extraElementsMemberMapIndex >> 5] |= 1U << (extraElementsMemberMapIndex & 31);
}
else if (_classMap.IgnoreExtraElements)
{
bsonReader.SkipValue();
}
else
{
var message = string.Format(
"Element '{0}' does not match any field or property of class {1}.",
elementName, _classMap.ClassType.FullName);
throw new Exception(message);
}
}
}
bsonReader.ReadEndDocument();
// check any members left over that we didn't have elements for (in blocks of 32 elements at a time)
for (var bitArrayIndex = 0; bitArrayIndex < memberMapBitArray.Length; ++bitArrayIndex)
{
memberMapIndex = bitArrayIndex << 5;
var memberMapBlock = ~memberMapBitArray[bitArrayIndex]; // notice that bits are flipped so 1's are now the missing elements
// work through this memberMapBlock of 32 elements
while (true)
{
// examine missing elements (memberMapBlock is shifted right as we work through the block)
for (; (memberMapBlock & 1) != 0; ++memberMapIndex, memberMapBlock >>= 1)
{
var memberMap = allMemberMaps[memberMapIndex];
if (memberMap.IsReadOnly)
{
continue;
}
if (memberMap.IsRequired)
{
var fieldOrProperty = (memberMap.MemberInfo.MemberType == MemberTypes.Field) ? "field" : "property";
var message = string.Format(
"Required element '{0}' for {1} '{2}' of class {3} is missing.",
memberMap.ElementName, fieldOrProperty, memberMap.MemberName, _classMap.ClassType.FullName);
throw new Exception(message);
}
if (obj != null)
{
memberMap.ApplyDefaultValue(obj);
}
else if (memberMap.IsDefaultValueSpecified && !memberMap.IsReadOnly)
{
values[memberMap.ElementName] = memberMap.DefaultValue;
}
}
if (memberMapBlock == 0)
{
break;
}
// skip ahead to the next missing element
var leastSignificantBit = FastMemberMapHelper.GetLeastSignificantBit(memberMapBlock);
memberMapIndex += leastSignificantBit;
memberMapBlock >>= leastSignificantBit;
}
}
if (obj != null)
{
if (supportsInitialization != null)
{
supportsInitialization.EndInit();
}
return obj;
}
else
{
return CreateInstanceUsingCreator(values);
}
}
}