EmptyCursor.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Persistence.Serialization;
 
namespace Waher.Persistence.Files.Searching
{
    internal class EmptyCursor<T> : ICursor<T>
    {
        internal EmptyCursor()
        {
        }
 
        public T Current => throw new InvalidOperationException("Enumeration not started. Call MoveNext() first.");
 
        public IObjectSerializer CurrentSerializer => throw new InvalidOperationException("Enumeration not started. Call MoveNext() first.");
 
        public bool CurrentTypeCompatible => false;
 
        Task<bool> IAsyncEnumerator.MoveNextAsync() => this.MoveNextAsyncLocked();
 
        object IEnumerator.Current => this.Current;
 
        public bool MoveNext() => this.MoveNextAsyncLocked().Result;
 
        public void Reset()
        {
        }
 
        public Guid CurrentObjectId => throw new InvalidOperationException("Enumeration not started. Call MoveNext() first.");
 
        public void Dispose()
        {
        }
 
        public Task<bool> MoveNextAsyncLocked()
        {
            return Task.FromResult(false);
        }
 
        public Task<bool> MovePreviousAsyncLocked()
        {
            return Task.FromResult(false);
        }
 
        public IEnumerator<T> GetEnumerator()
        {
            T[] A = Array.Empty<T>();
            return (IEnumerator<T>)A.GetEnumerator();
        }
 
        public bool SameSortOrder(string[] ConstantFields, string[] SortOrder)
        {
            return false;
        }
 
        public bool ReverseSortOrder(string[] ConstantFields, string[] SortOrder)
        {
            return false;
        }
 
        public Task ContinueAfterLocked(T LastItem)
        {
            return Task.CompletedTask;
        }
 
        public Task ContinueBeforeLocked(T LastItem)
        {
            return Task.CompletedTask;
        }
 
        public bool CanSkip => false;
 
        public Task<bool> Skip(long NrObjects)
        {
            return Task.FromResult(false);
        }
    }
}