Lidarr/NzbDrone.Api/Extensions/LazyExtensions.cs

54 lines
1.8 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using NzbDrone.Api.REST;
using NzbDrone.Common.Cache;
using NzbDrone.Core.Datastore;
namespace NzbDrone.Api.Extensions
{
public static class LazyExtensions
{
private static readonly ICached<MethodInfo> SetterCache = new Cached<MethodInfo>();
public static IEnumerable<TParent> LoadSubtype<TParent, TChild>(this IEnumerable<TParent> parents, Func<TParent, int> foreignKeySelector, IBasicRepository<TChild> childRepository)
where TChild : ModelBase, new()
where TParent : RestResource
{
var parentList = parents.Where(p => foreignKeySelector(p) != 0).ToList();
if (!parentList.Any())
{
return parents;
}
var ids = parentList.Select(foreignKeySelector).Distinct();
var childDictionary = childRepository.Get(ids).ToDictionary(child => child.Id, child => child);
var childSetter = GetChildSetter<TParent, TChild>();
foreach (var episode in parentList)
{
childSetter.Invoke(episode, new object[] { childDictionary[foreignKeySelector(episode)] });
}
return parents;
}
private static MethodInfo GetChildSetter<TParent, TChild>()
where TChild : ModelBase
where TParent : RestResource
{
var key = typeof(TChild).FullName + typeof(TParent).FullName;
return SetterCache.Get(key, () =>
{
var property = typeof(TParent).GetProperties().Single(c => c.PropertyType == typeof(TChild));
return property.GetSetMethod();
});
}
}
}