public SqlExpression Visit(SqlExpression expression)
{
if (expression == null)
throw new ArgumentNullException("expression");
return Visit((dynamic) expression);
}
protected override Expression VisitMethodCall(MethodCallExpression expression)
{
Visit(expression.Arguments[0]);
switch (expression.Method.Name)
{
case "Select":
Select = SelectParser.Translate(expression.Arguments[1]);
// if it changes the return type make it known that this is a projection and should not be tracked in session
var inType = expression.Arguments[0].Type.GetGenericArguments()[0];
var outType = expression.Method.ReturnType.GetGenericArguments()[0];
ProjectAs = inType != outType ? outType : null;
break;
case "SingleOrDefault":
Execution = Translation.ExecutionSemantics.SingleOrDefault;
goto Take1;
case "Single":
Execution = Translation.ExecutionSemantics.Single;
goto Take1;
case "FirstOrDefault":
Execution = Translation.ExecutionSemantics.FirstOrDefault;
goto Take1;
case "First":
Execution = Translation.ExecutionSemantics.First;
goto Take1;
case "Take1":
Take1:
Take = 1;
if (expression.Arguments.Count <= 1) break;
goto Where;
case "Where":
Where:
var whereExpression = WhereParser.Translate(expression.Arguments[1]);
if (whereExpression == null)
break;
Where = Where != null
? new SqlBinaryExpression(SqlNodeType.And, Where, whereExpression)
: whereExpression;
break;
case "Skip":
Skip = (int) ((ConstantExpression) expression.Arguments[1]).Value;
break;
case "Take":
Take = (int) ((ConstantExpression) expression.Arguments[1]).Value;
break;
case "OfType":
ProjectAs = expression.Method.GetGenericArguments()[0];
break;
case "OrderBy":
case "ThenBy":
case "OrderByDescending":
case "ThenByDescending":
var direction = expression.Method.Name.Contains("Descending")
? SqlOrderingExpression.Directions.Descending
: SqlOrderingExpression.Directions.Ascending;
var orderByColumnExpression = OrderByVisitor.Translate(expression.Arguments[1]);
var orderingExpression = new SqlOrderingExpression(direction, orderByColumnExpression);
OrderBy = OrderBy != null
? new SqlOrderByExpression(OrderBy.Columns.Concat(orderingExpression))
: new SqlOrderByExpression(orderingExpression.AsEnumerable());
break;
default:
throw new NotSupportedException(string.Format("The method {0} is not supported", expression.Method.Name));
}
return expression;
}
