private static MethodCallExpression CountExpression(ParameterExpression sourceParameter)
{
Type itemType = OeExpressionHelper.GetCollectionItemType(sourceParameter.Type);
MethodInfo countMethodInfo = OeMethodInfoHelper.GetCountMethodInfo(itemType);
return(Expression.Call(countMethodInfo, sourceParameter));
}
private static MethodCallExpression CountDistinctExpression(ParameterExpression sourceParameter, LambdaExpression lambda)
{
MethodInfo selectMetodInfo = OeMethodInfoHelper.GetSelectMethodInfo(lambda.Parameters[0].Type, lambda.ReturnType);
MethodCallExpression selectCall = Expression.Call(selectMetodInfo, sourceParameter, lambda);
MethodInfo distinctMethodInfo = OeMethodInfoHelper.GetDistinctMethodInfo(lambda.ReturnType);
MethodCallExpression distinctCall = Expression.Call(distinctMethodInfo, selectCall);
MethodInfo countMethodInfo = OeMethodInfoHelper.GetCountMethodInfo(lambda.ReturnType);
return(Expression.Call(countMethodInfo, distinctCall));
}
internal MethodCallExpression BuildExpandCount(Expression outer, Expression inner, OeNavigationSelectItem navigationItem)
{
IEdmNavigationProperty navigationProperty = navigationItem.EdmProperty;
if (navigationItem.EdmProperty.ContainsTarget)
{
throw new InvalidOperationException("Expand cout for many-tomany not supported");
}
Type outerType = OeExpressionHelper.GetCollectionItemType(outer.Type);
Type innerType = OeExpressionHelper.GetCollectionItemType(inner.Type);
ParameterExpression outerParameter = Expression.Parameter(outerType, outerType.Name);
IReadOnlyList <IEdmNavigationProperty> joinPath = navigationItem.Parent == null?Array.Empty <IEdmNavigationProperty>() : navigationItem.Parent.GetJoinPath();
Expression?joinPropertyExpression = _expressionBuilder.JoinBuilder.GetJoinPropertyExpression(outerParameter, joinPath);
if (joinPropertyExpression == null)
{
throw new InvalidOperationException("Outer source not found");
}
MethodCallExpression subquery = CreateWhereExpression(joinPropertyExpression, inner, navigationProperty);
MethodInfo methodInfo = OeMethodInfoHelper.GetCountMethodInfo(innerType);
subquery = Expression.Call(methodInfo, subquery);
List <Expression> expressions = new List <Expression>();
if (OeExpressionHelper.IsTupleType(outerParameter.Type))
{
expressions.AddRange(OeExpressionHelper.GetPropertyExpressions(outerParameter));
}
else
{
expressions.Add(outerParameter);
}
expressions.Add(OeExpressionHelper.CreateTupleExpression(new[] { subquery }));
NewExpression newTuple = OeExpressionHelper.CreateTupleExpression(expressions);
methodInfo = OeMethodInfoHelper.GetSelectMethodInfo(outerType, newTuple.Type);
return(Expression.Call(methodInfo, outer, Expression.Lambda(newTuple, outerParameter)));
}
