Fix warnings in Playlists

Emby.Server.Implementations/Playlists/PlaylistsFolder.cs

@@ -0,0 +1,58 @@
+#pragma warning disable CS1591
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json.Serialization;
+using Jellyfin.Data.Entities;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Playlists;
+using MediaBrowser.Model.Querying;
+
+namespace Emby.Server.Implementations.Playlists
+{
+    public class PlaylistsFolder : BasePluginFolder
+    {
+        public PlaylistsFolder()
+        {
+            Name = "Playlists";
+        }
+
+        [JsonIgnore]
+        public override bool IsHidden => true;
+
+        [JsonIgnore]
+        public override bool SupportsInheritedParentImages => false;
+
+        [JsonIgnore]
+        public override string CollectionType => MediaBrowser.Model.Entities.CollectionType.Playlists;
+
+        public override bool IsVisible(User user)
+        {
+            return base.IsVisible(user) && GetChildren(user, true).Any();
+        }
+
+        protected override IEnumerable<BaseItem> GetEligibleChildrenForRecursiveChildren(User user)
+        {
+            return base.GetEligibleChildrenForRecursiveChildren(user).OfType<Playlist>();
+        }
+
+        protected override QueryResult<BaseItem> GetItemsInternal(InternalItemsQuery query)
+        {
+            if (query.User == null)
+            {
+                query.Recursive = false;
+                return base.GetItemsInternal(query);
+            }
+
+            query.Recursive = true;
+            query.IncludeItemTypes = new[] { "Playlist" };
+            query.Parent = null;
+            return LibraryManager.GetItemsResult(query);
+        }
+
+        public override string GetClientTypeName()
+        {
+            return "ManualPlaylistsFolder";
+        }
+    }
+}