private bool TryTranslateAllResultOperator(PipelineExpression node, out BsonValue result)
{
var resultOperator = node.ResultOperator as AllResultOperator;
if (resultOperator != null)
{
var whereExpression = node.Source as WhereExpression;
if (whereExpression != null)
{
var inValue = TranslateValue(FieldNamePrefixer.Prefix(whereExpression.Predicate, "$" + whereExpression.ItemName));
result = new BsonDocument("$map", new BsonDocument
{
{ "input", TranslateValue(whereExpression.Source) },
{ "as", whereExpression.ItemName },
{ "in", inValue }
});
result = new BsonDocument("$allElementsTrue", result);
return(true);
}
}
result = null;
return(false);
}
private BsonValue TranslateWhere(WhereExpression node)
{
var inputValue = TranslateValue(node.Source);
var condValue = TranslateValue(FieldNamePrefixer.Prefix(node.Predicate, "$" + node.ItemName));
return(new BsonDocument("$filter", new BsonDocument
{
{ "input", inputValue },
{ "as", node.ItemName },
{ "cond", condValue }
}));
}
private BsonValue TranslateSelect(SelectExpression node)
{
if (node.Source is IFieldExpression && node.Selector is IFieldExpression)
{
var prefixName = ((IFieldExpression)node.Source).FieldName;
return(TranslateValue(FieldNamePrefixer.Prefix(node.Selector, prefixName)));
}
var inputValue = TranslateValue(node.Source);
var inValue = TranslateValue(FieldNamePrefixer.Prefix(node.Selector, "$" + node.ItemName));
return(new BsonDocument("$map", new BsonDocument
{
{ "input", inputValue },
{ "as", node.ItemName },
{ "in", inValue }
}));
}
private BsonValue TranslateSelect(SelectExpression node)
{
var inputValue = TranslateValue(node.Source);
var inValue = TranslateValue(FieldNamePrefixer.Prefix(node.Selector, "$" + node.ItemName));
if (inputValue.BsonType == BsonType.String && inValue.BsonType == BsonType.String)
{
// if inputValue is a BsonString and inValue is a BsonString,
// then it is a simple field inclusion...
// inValue is prefixed with a $${node.ItemName}, so we remove the itemName and the 2 $s.
return(inputValue.ToString() + inValue.ToString().Substring(node.ItemName.Length + 2));
}
return(new BsonDocument("$map", new BsonDocument
{
{ "input", inputValue },
{ "as", node.ItemName },
{ "in", inValue }
}));
}
public static Expression Prefix(Expression node, string prefix)
{
var replacer = new FieldNamePrefixer(prefix);
return(replacer.Visit(node));
}
public static Expression Prefix(Expression node, string prefix)
{
var replacer = new FieldNamePrefixer(prefix);
return replacer.Visit(node);
}
