// caller is responsible for ensuring constant is on the right
public static AstFilter Translate(
TranslationContext context,
Expression expression,
Expression leftExpression,
AstComparisonFilterOperator comparisonOperator,
Expression rightExpression)
{
if (leftExpression is BinaryExpression leftBinaryExpression &&
leftBinaryExpression.NodeType == ExpressionType.And)
{
var fieldExpression = leftBinaryExpression.Left;
var field = ExpressionToFilterFieldTranslator.Translate(context, fieldExpression);
var bitMaskExpression = leftBinaryExpression.Right;
var bitMask = bitMaskExpression.GetConstantValue <object>(containingExpression: expression);
var serializedBitMask = SerializationHelper.SerializeValue(field.Serializer, bitMask);
var rightValue = rightExpression.GetConstantValue <object>(containingExpression: expression);
var zeroValue = Activator.CreateInstance(bitMask.GetType());
switch (comparisonOperator)
{
case AstComparisonFilterOperator.Eq:
if (rightValue.Equals(zeroValue))
{
return(AstFilter.BitsAllClear(field, serializedBitMask));
}
else if (rightValue.Equals(bitMask))
{
return(AstFilter.BitsAllSet(field, serializedBitMask));
}
break;
case AstComparisonFilterOperator.Ne:
if (rightValue.Equals(zeroValue))
{
return(AstFilter.BitsAnySet(field, serializedBitMask));
}
else if (rightValue.Equals(bitMask))
{
return(AstFilter.BitsAnyClear(field, serializedBitMask));
}
break;
}
}
throw new ExpressionNotSupportedException(expression);
}
// public static methods
public static AstFilter Translate(TranslationContext context, MethodCallExpression expression)
{
var method = expression.Method;
var arguments = expression.Arguments;
if (method.Is(EnumMethod.HasFlag))
{
var fieldExpression = expression.Object;
var field = ExpressionToFilterFieldTranslator.Translate(context, fieldExpression);
var flagExpression = arguments[0];
var flag = flagExpression.GetConstantValue <object>(containingExpression: expression);
var serializedFlag = SerializationHelper.SerializeValue(field.Serializer, flag);
return(AstFilter.BitsAllSet(field, serializedFlag));
}
throw new ExpressionNotSupportedException(expression);
}