/// <inheritdoc />
protected override Expression VisitMethodCall(MethodCallExpression expression)
{
LogWriter.WriteLine($"VisitMethodCall: {expression}, method {expression.Method.Name}, args: {string.Join(", ",expression.Arguments.Select(a => a.ToString()))}");
var method = expression.Method;
switch (method.Name)
{
case "Contains":
case "StartsWith":
case "EndsWith":
var obj = Evaluate(expression.Object);
var pattern = Evaluate(expression.Arguments[0]);
_state.SetColumn(obj.ToString());
_state.SetFunction(method.Name, pattern);
return(expression);
case "Min":
case "Max":
case "Count":
case "Average":
case "Sum":
using (_state.PushCollectorMode(QueryCollectionState.Aggregate))
{
object value = null;
if (expression.Arguments.Count > 1)
{
throw new InvalidOperationException($"Unsupported number of aggregate function arguments: {expression.Arguments.Count}");
}
if (expression.Arguments.Count > 0)
{
value = Evaluate(expression.Arguments[0]);
}
_state.SetFunction(method.Name, value);
}
return(expression);
case "Column":
var columnName = Evaluate(expression.Arguments[0]).ToString();
_arguments.Push(columnName);
_state.SetColumn(columnName);
return(expression);
}
return(base.VisitMethodCall(expression)); // throws
}
/// <inheritdoc />
public override void VisitResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, int index)
{
LogWriter.WriteLine($"VisitResultOperator: {resultOperator}, type {resultOperator.GetType().Name}");
switch (resultOperator)
{
// First()
case FirstResultOperator _:
_collector.Take = 1;
break;
// Count()
case CountResultOperator _:
case LongCountResultOperator _:
_collector.SetResultAggregationType(AggregationTypeStrict.Count);
break;
// Take()
case TakeResultOperator takeOperator:
var takeExpr = takeOperator.Count;
if (takeExpr.NodeType == ExpressionType.Constant)
{
_collector.Take = (int)((ConstantExpression)takeExpr).Value;
}
else
{
throw new NotSupportedException("Currently not supporting methods or variables in the Skip or Take clause.");
}
break;
// Skip()
case SkipResultOperator skipOperator:
var skipExpr = skipOperator.Count;
if (skipExpr.NodeType == ExpressionType.Constant)
{
_collector.Skip = (int)((ConstantExpression)skipExpr).Value;
}
else
{
throw new NotSupportedException("Currently not supporting methods or variables in the Skip or Take clause.");
}
break;
// Min()
case MinResultOperator _:
_state.SetFunction("Min", null);
break;
// Max()
case MaxResultOperator _:
_state.SetFunction("Max", null);
break;
// Average()
case AverageResultOperator _:
_state.SetFunction("Average", null);
break;
// GroupBy()
case GroupResultOperator groupOperator:
using (_state.PushCollectorMode(QueryCollectionState.GroupBy))
{
var key = groupOperator.KeySelector;
var elementSelector = groupOperator.ElementSelector;
UpdateEntitySchemaQueryExpression(key);
UpdateEntitySchemaQueryExpression(elementSelector);
if (key is NewExpression newKeySelector)
{
int position = 0;
foreach (var memberInfo in newKeySelector.Members)
{
_state.SetColumnAlias(position++, memberInfo.Name);
}
}
}
break;
}
}