10 files changed, 106 insertions, 36 deletions
diff --git a/MediaBrowser.Controller/Dto/IDtoService.cs b/MediaBrowser.Controller/Dto/IDtoService.cs
index 4b6fd58fe..ba693a065 100644
--- a/MediaBrowser.Controller/Dto/IDtoService.cs
+++ b/MediaBrowser.Controller/Dto/IDtoService.cs
@@ -57,7 +57,7 @@ namespace MediaBrowser.Controller.Dto
         /// <param name="options">The options.</param>
         /// <param name="user">The user.</param>
         /// <param name="owner">The owner.</param>
-        BaseItemDto[] GetBaseItemDtos(IReadOnlyList<BaseItem> items, DtoOptions options, User user = null, BaseItem owner = null);
+        IReadOnlyList<BaseItemDto> GetBaseItemDtos(IReadOnlyList<BaseItem> items, DtoOptions options, User user = null, BaseItem owner = null);
 
         /// <summary>
         /// Gets the item by name dto.
diff --git a/MediaBrowser.Controller/Entities/BaseItem.cs b/MediaBrowser.Controller/Entities/BaseItem.cs
index 38e4db3cf..0e9f7ee44 100644
--- a/MediaBrowser.Controller/Entities/BaseItem.cs
+++ b/MediaBrowser.Controller/Entities/BaseItem.cs
@@ -2871,16 +2871,16 @@ namespace MediaBrowser.Controller.Entities
         /// Gets or sets the remote trailers.
         /// </summary>
         /// <value>The remote trailers.</value>
-        public MediaUrl[] RemoteTrailers { get; set; }
+        public IReadOnlyList<MediaUrl> RemoteTrailers { get; set; }
 
         public IEnumerable<BaseItem> GetExtras()
         {
             return ExtraIds.Select(LibraryManager.GetItemById).Where(i => i != null).OrderBy(i => i.SortName);
         }
 
-        public IEnumerable<BaseItem> GetExtras(ExtraType[] extraTypes)
+        public IEnumerable<BaseItem> GetExtras(IReadOnlyCollection<ExtraType> extraTypes)
         {
-            return ExtraIds.Select(LibraryManager.GetItemById).Where(i => i != null && extraTypes.Contains(i.ExtraType.Value)).OrderBy(i => i.SortName);
+            return ExtraIds.Select(LibraryManager.GetItemById).Where(i => i != null && extraTypes.Contains(i.ExtraType.Value));
         }
 
         public IEnumerable<BaseItem> GetTrailers()
@@ -2908,7 +2908,7 @@ namespace MediaBrowser.Controller.Entities
         }
 
         // Possible types of extra videos
-        public static ExtraType[] DisplayExtraTypes = new[] { Model.Entities.ExtraType.BehindTheScenes, Model.Entities.ExtraType.Clip, Model.Entities.ExtraType.DeletedScene, Model.Entities.ExtraType.Interview, Model.Entities.ExtraType.Sample, Model.Entities.ExtraType.Scene };
+        public static readonly IReadOnlyCollection<ExtraType> DisplayExtraTypes = new[] { Model.Entities.ExtraType.BehindTheScenes, Model.Entities.ExtraType.Clip, Model.Entities.ExtraType.DeletedScene, Model.Entities.ExtraType.Interview, Model.Entities.ExtraType.Sample, Model.Entities.ExtraType.Scene };
 
         public virtual bool SupportsExternalTransfer => false;
     }
diff --git a/MediaBrowser.Controller/Entities/Extensions.cs b/MediaBrowser.Controller/Entities/Extensions.cs
index f3bddd29c..d2ca11740 100644
--- a/MediaBrowser.Controller/Entities/Extensions.cs
+++ b/MediaBrowser.Controller/Entities/Extensions.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using MediaBrowser.Common.Extensions;
 using MediaBrowser.Model.Entities;
 
 namespace MediaBrowser.Controller.Entities
@@ -28,13 +29,17 @@ namespace MediaBrowser.Controller.Entities
                     Url = url
                 };
 
-                if (item.RemoteTrailers.Length == 0)
+                if (item.RemoteTrailers.Count == 0)
                 {
                     item.RemoteTrailers = new[] { mediaUrl };
                 }
                 else
                 {
-                    item.RemoteTrailers = item.RemoteTrailers.Concat(new[] { mediaUrl }).ToArray();
+                    var oldIds = item.RemoteTrailers;
+                    var newIds = new MediaUrl[oldIds.Count + 1];
+                    oldIds.CopyTo(newIds);
+                    newIds[oldIds.Count] = mediaUrl;
+                    item.RemoteTrailers = newIds;
                 }
             }
         }
diff --git a/MediaBrowser.Controller/Entities/Folder.cs b/MediaBrowser.Controller/Entities/Folder.cs
index d841b7ef8..d61a07066 100644
--- a/MediaBrowser.Controller/Entities/Folder.cs
+++ b/MediaBrowser.Controller/Entities/Folder.cs
@@ -666,36 +666,36 @@ namespace MediaBrowser.Controller.Entities
             query.StartIndex = null;
             query.Limit = null;
 
-            var itemsList = LibraryManager.GetItemList(query);
+            IEnumerable<BaseItem> itemsList = LibraryManager.GetItemList(query);
             var user = query.User;
 
             if (user != null)
             {
                 // needed for boxsets
-                itemsList = itemsList.Where(i => i.IsVisibleStandalone(query.User)).ToList();
+                itemsList = itemsList.Where(i => i.IsVisibleStandalone(query.User));
             }
 
-            BaseItem[] returnItems;
+            IEnumerable<BaseItem> returnItems;
             int totalCount = 0;
 
             if (query.EnableTotalRecordCount)
             {
-                var itemsArray = itemsList.ToArray();
-                totalCount = itemsArray.Length;
-                returnItems = itemsArray;
+                var itemArray = itemsList.ToArray();
+                totalCount = itemArray.Length;
+                returnItems = itemArray;
             }
             else
             {
-                returnItems = itemsList.ToArray();
+                returnItems = itemsList;
             }
 
             if (limit.HasValue)
             {
-                returnItems = returnItems.Skip(startIndex ?? 0).Take(limit.Value).ToArray();
+                returnItems = returnItems.Skip(startIndex ?? 0).Take(limit.Value);
             }
             else if (startIndex.HasValue)
             {
-                returnItems = returnItems.Skip(startIndex.Value).ToArray();
+                returnItems = returnItems.Skip(startIndex.Value);
             }
 
             return new QueryResult<BaseItem>
diff --git a/MediaBrowser.Controller/Entities/IHasTrailers.cs b/MediaBrowser.Controller/Entities/IHasTrailers.cs
index 3bdb9b64a..dd8e3c45f 100644
--- a/MediaBrowser.Controller/Entities/IHasTrailers.cs
+++ b/MediaBrowser.Controller/Entities/IHasTrailers.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using MediaBrowser.Model.Entities;
 
 namespace MediaBrowser.Controller.Entities
@@ -11,29 +10,82 @@ namespace MediaBrowser.Controller.Entities
         /// Gets or sets the remote trailers.
         /// </summary>
         /// <value>The remote trailers.</value>
-        MediaUrl[] RemoteTrailers { get; set; }
+        IReadOnlyList<MediaUrl> RemoteTrailers { get; set; }
 
         /// <summary>
         /// Gets or sets the local trailer ids.
         /// </summary>
         /// <value>The local trailer ids.</value>
-        Guid[] LocalTrailerIds { get; set; }
-        Guid[] RemoteTrailerIds { get; set; }
+        IReadOnlyList<Guid> LocalTrailerIds { get; set; }
+
+        /// <summary>
+        /// Gets or sets the remote trailer ids.
+        /// </summary>
+        /// <value>The remote trailer ids.</value>
+        IReadOnlyList<Guid> RemoteTrailerIds { get; set; }
+
         Guid Id { get; set; }
     }
 
+    /// <summary>
+    /// Class providing extension methods for working with <see cref="IHasTrailers" />.
+    /// </summary>
     public static class HasTrailerExtensions
     {
         /// <summary>
+        /// Gets the trailer count.
+        /// </summary>
+        /// <returns><see cref="IReadOnlyList{Guid}" />.</returns>
+        public static int GetTrailerCount(this IHasTrailers item)
+            => item.LocalTrailerIds.Count + item.RemoteTrailerIds.Count;
+
+        /// <summary>
         /// Gets the trailer ids.
         /// </summary>
-        /// <returns>List&lt;Guid&gt;.</returns>
-        public static List<Guid> GetTrailerIds(this IHasTrailers item)
+        /// <returns><see cref="IReadOnlyList{Guid}" />.</returns>
+        public static IReadOnlyList<Guid> GetTrailerIds(this IHasTrailers item)
         {
-            var list = item.LocalTrailerIds.ToList();
-            list.AddRange(item.RemoteTrailerIds);
-            return list;
+            var localIds = item.LocalTrailerIds;
+            var remoteIds = item.RemoteTrailerIds;
+
+            var all = new Guid[localIds.Count + remoteIds.Count];
+            var index = 0;
+            foreach (var id in localIds)
+            {
+                all[index++] = id;
+            }
+
+            foreach (var id in remoteIds)
+            {
+                all[index++] = id;
+            }
+
+            return all;
         }
 
+        /// <summary>
+        /// Gets the trailers.
+        /// </summary>
+        /// <returns><see cref="IReadOnlyList{BaseItem}" />.</returns>
+        public static IReadOnlyList<BaseItem> GetTrailers(this IHasTrailers item)
+        {
+            var localIds = item.LocalTrailerIds;
+            var remoteIds = item.RemoteTrailerIds;
+            var libraryManager = BaseItem.LibraryManager;
+
+            var all = new BaseItem[localIds.Count + remoteIds.Count];
+            var index = 0;
+            foreach (var id in localIds)
+            {
+                all[index++] = libraryManager.GetItemById(id);
+            }
+
+            foreach (var id in remoteIds)
+            {
+                all[index++] = libraryManager.GetItemById(id);
+            }
+
+            return all;
+        }
     }
 }
diff --git a/MediaBrowser.Controller/Entities/Movies/BoxSet.cs b/MediaBrowser.Controller/Entities/Movies/BoxSet.cs
index a532b5ee9..e7ac2a05c 100644
--- a/MediaBrowser.Controller/Entities/Movies/BoxSet.cs
+++ b/MediaBrowser.Controller/Entities/Movies/BoxSet.cs
@@ -33,8 +33,11 @@ namespace MediaBrowser.Controller.Entities.Movies
         [IgnoreDataMember]
         public override bool SupportsPeople => true;
 
-        public Guid[] LocalTrailerIds { get; set; }
-        public Guid[] RemoteTrailerIds { get; set; }
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> LocalTrailerIds { get; set; }
+
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> RemoteTrailerIds { get; set; }
 
         /// <summary>
         /// Gets or sets the display order.
@@ -61,7 +64,8 @@ namespace MediaBrowser.Controller.Entities.Movies
             {
                 return base.GetNonCachedChildren(directoryService);
             }
-            return new List<BaseItem>();
+
+            return Enumerable.Empty<BaseItem>();
         }
 
         protected override List<BaseItem> LoadChildren()
diff --git a/MediaBrowser.Controller/Entities/Movies/Movie.cs b/MediaBrowser.Controller/Entities/Movies/Movie.cs
index 20c5b3521..184528fdc 100644
--- a/MediaBrowser.Controller/Entities/Movies/Movie.cs
+++ b/MediaBrowser.Controller/Entities/Movies/Movie.cs
@@ -27,8 +27,11 @@ namespace MediaBrowser.Controller.Entities.Movies
             RemoteTrailerIds = Array.Empty<Guid>();
         }
 
-        public Guid[] LocalTrailerIds { get; set; }
-        public Guid[] RemoteTrailerIds { get; set; }
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> LocalTrailerIds { get; set; }
+
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> RemoteTrailerIds { get; set; }
 
         /// <summary>
         /// Gets or sets the name of the TMDB collection.
diff --git a/MediaBrowser.Controller/Entities/TV/Episode.cs b/MediaBrowser.Controller/Entities/TV/Episode.cs
index fb29c07b0..e67c00fed 100644
--- a/MediaBrowser.Controller/Entities/TV/Episode.cs
+++ b/MediaBrowser.Controller/Entities/TV/Episode.cs
@@ -23,8 +23,11 @@ namespace MediaBrowser.Controller.Entities.TV
             RemoteTrailerIds = Array.Empty<Guid>();
         }
 
-        public Guid[] LocalTrailerIds { get; set; }
-        public Guid[] RemoteTrailerIds { get; set; }
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> LocalTrailerIds { get; set; }
+
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> RemoteTrailerIds { get; set; }
 
         /// <summary>
         /// Gets the season in which it aired.
diff --git a/MediaBrowser.Controller/Entities/TV/Series.cs b/MediaBrowser.Controller/Entities/TV/Series.cs
index 1aacc13c9..a50da9b0a 100644
--- a/MediaBrowser.Controller/Entities/TV/Series.cs
+++ b/MediaBrowser.Controller/Entities/TV/Series.cs
@@ -46,8 +46,11 @@ namespace MediaBrowser.Controller.Entities.TV
         [IgnoreDataMember]
         public override bool SupportsPeople => true;
 
-        public Guid[] LocalTrailerIds { get; set; }
-        public Guid[] RemoteTrailerIds { get; set; }
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> LocalTrailerIds { get; set; }
+
+        /// <inheritdoc />
+        public IReadOnlyList<Guid> RemoteTrailerIds { get; set; }
 
         /// <summary>
         /// airdate, dvd or absolute
diff --git a/MediaBrowser.Controller/LiveTv/ILiveTvManager.cs b/MediaBrowser.Controller/LiveTv/ILiveTvManager.cs
index f99df6c7c..e02c387e4 100644
--- a/MediaBrowser.Controller/LiveTv/ILiveTvManager.cs
+++ b/MediaBrowser.Controller/LiveTv/ILiveTvManager.cs
@@ -221,7 +221,7 @@ namespace MediaBrowser.Controller.LiveTv
         /// <param name="fields">The fields.</param>
         /// <param name="user">The user.</param>
         /// <returns>Task.</returns>
-        Task AddInfoToProgramDto(List<Tuple<BaseItem, BaseItemDto>> programs, ItemFields[] fields, User user = null);
+        Task AddInfoToProgramDto(IReadOnlyCollection<(BaseItem, BaseItemDto)> programs, ItemFields[] fields, User user = null);
 
         /// <summary>
         /// Saves the tuner host.
@@ -258,7 +258,7 @@ namespace MediaBrowser.Controller.LiveTv
         /// <param name="items">The items.</param>
         /// <param name="options">The options.</param>
         /// <param name="user">The user.</param>
-        void AddChannelInfo(List<Tuple<BaseItemDto, LiveTvChannel>> items, DtoOptions options, User user);
+        void AddChannelInfo(IReadOnlyCollection<(BaseItemDto, LiveTvChannel)> items, DtoOptions options, User user);
 
         Task<List<ChannelInfo>> GetChannelsForListingsProvider(string id, CancellationToken cancellationToken);
         Task<List<ChannelInfo>> GetChannelsFromListingsProviderData(string id, CancellationToken cancellationToken);