/// <summary>
/// Finds out if the given <paramref name="orderingInfo"/> required a skip token
/// expression in the expansion
/// </summary>
/// <param name="orderingInfo">Input orderingInfo.</param>
/// <returns>true if skip token expression is needed, false otherwise</returns>
internal static bool IsSkipTokenRequired(OrderingInfo orderingInfo)
{
if (orderingInfo != null && orderingInfo.IsPaged)
{
foreach (OrderingExpression o in orderingInfo.OrderingExpressions)
{
LambdaExpression l = (LambdaExpression)o.Expression;
NeedSkipTokenVisitor visitor = new NeedSkipTokenVisitor();
visitor.Visit(l.Body);
if (visitor.NeedSkipToken)
{
return true;
}
}
}
return false;
}
/// <summary>
/// Finds out if the given <paramref name="orderingInfo"/> required a skip token
/// expression in the expansion
/// </summary>
/// <param name="orderingInfo">Input orderingInfo.</param>
/// <returns>true if skip token expression is needed, false otherwise</returns>
internal static bool IsSkipTokenRequired(OrderingInfo orderingInfo)
{
if (orderingInfo != null && orderingInfo.IsPaged)
{
foreach (OrderingExpression o in orderingInfo.OrderingExpressions)
{
LambdaExpression l = (LambdaExpression)o.Expression;
NeedSkipTokenVisitor visitor = new NeedSkipTokenVisitor();
visitor.Visit(l.Body);
if (visitor.NeedSkipToken)
{
return(true);
}
}
}
return(false);
}
/// <summary>
/// Obtains a collection of resource properties that are needed for skip token generation
/// </summary>
/// <param name="orderingInfo">Input orderingInfo.</param>
/// <param name="rt">Resource type for which to collect the skip token properties</param>
/// <returns>Collection of resource properties used in $skiptoken</returns>
internal static ICollection <ResourceProperty> CollectSkipTokenProperties(OrderingInfo orderingInfo, ResourceType rt)
{
Debug.Assert(orderingInfo != null, "Must have valid ordering information to collect skip token properties");
Debug.Assert(orderingInfo.IsPaged, "Must have paging enabled to collection skip token properties");
List <ResourceProperty> resourceProperties = new List <ResourceProperty>();
foreach (OrderingExpression o in orderingInfo.OrderingExpressions)
{
LambdaExpression l = (LambdaExpression)o.Expression;
NeedSkipTokenVisitor visitor = new NeedSkipTokenVisitor(rt);
visitor.Visit(l.Body);
if (visitor.NeedSkipToken)
{
return(null);
}
Debug.Assert(visitor.Property != null, "Must have a valid property if skip token is not needed");
resourceProperties.Add(visitor.Property);
}
return(resourceProperties);
}
/// <summary>
/// Obtains a collection of resource properties that are needed for skip token generation
/// </summary>
/// <param name="orderingInfo">Input orderingInfo.</param>
/// <param name="rt">Resource type for which to collect the skip token properties</param>
/// <returns>Collection of resource properties used in $skiptoken</returns>
internal static ICollection<ResourceProperty> CollectSkipTokenProperties(OrderingInfo orderingInfo, ResourceType rt)
{
Debug.Assert(orderingInfo != null, "Must have valid ordering information to collect skip token properties");
Debug.Assert(orderingInfo.IsPaged, "Must have paging enabled to collection skip token properties");
List<ResourceProperty> resourceProperties = new List<ResourceProperty>();
foreach (OrderingExpression o in orderingInfo.OrderingExpressions)
{
LambdaExpression l = (LambdaExpression)o.Expression;
NeedSkipTokenVisitor visitor = new NeedSkipTokenVisitor(rt);
visitor.Visit(l.Body);
if (visitor.NeedSkipToken)
{
return null;
}
Debug.Assert(visitor.Property != null, "Must have a valid property if skip token is not needed");
resourceProperties.Add(visitor.Property);
}
return resourceProperties;
}