Optimize Guid comparisons

* Use Guid.Equals(Guid) instead of the == override
* Ban the usage of Guid.Equals(Object) to prevent accidental boxing
* Compare to default(Guid) instead of Guid.Empty

Emby.Server.Implementations/Library/LibraryManager.cs

@@ -755,7 +755,7 @@ namespace Emby.Server.Implementations.Library
                 Path = path
             };
 
-            if (folder.Id.Equals(Guid.Empty))
+            if (folder.Id.Equals(default))
             {
                 if (string.IsNullOrEmpty(folder.Path))
                 {
@@ -774,7 +774,7 @@ namespace Emby.Server.Implementations.Library
                 folder = dbItem;
             }
 
-            if (folder.ParentId != rootFolder.Id)
+            if (!folder.ParentId.Equals(rootFolder.Id))
             {
                 folder.ParentId = rootFolder.Id;
                 folder.UpdateToRepositoryAsync(ItemUpdateType.MetadataImport, CancellationToken.None).GetAwaiter().GetResult();
@@ -1252,7 +1252,7 @@ namespace Emby.Server.Implementations.Library
         /// <exception cref="ArgumentNullException"><paramref name="id"/> is <c>null</c>.</exception>
         public BaseItem GetItemById(Guid id)
         {
-            if (id == Guid.Empty)
+            if (id.Equals(default))
             {
                 throw new ArgumentException("Guid can't be empty", nameof(id));
             }
@@ -1274,7 +1274,7 @@ namespace Emby.Server.Implementations.Library
 
         public List<BaseItem> GetItemList(InternalItemsQuery query, bool allowExternalContent)
         {
-            if (query.Recursive && query.ParentId != Guid.Empty)
+            if (query.Recursive && !query.ParentId.Equals(default))
             {
                 var parent = GetItemById(query.ParentId);
                 if (parent != null)
@@ -1298,7 +1298,7 @@ namespace Emby.Server.Implementations.Library
 
         public int GetCount(InternalItemsQuery query)
         {
-            if (query.Recursive && !query.ParentId.Equals(Guid.Empty))
+            if (query.Recursive && !query.ParentId.Equals(default))
             {
                 var parent = GetItemById(query.ParentId);
                 if (parent != null)
@@ -1456,7 +1456,7 @@ namespace Emby.Server.Implementations.Library
 
         public QueryResult<BaseItem> GetItemsResult(InternalItemsQuery query)
         {
-            if (query.Recursive && !query.ParentId.Equals(Guid.Empty))
+            if (query.Recursive && !query.ParentId.Equals(default))
             {
                 var parent = GetItemById(query.ParentId);
                 if (parent != null)
@@ -1512,7 +1512,7 @@ namespace Emby.Server.Implementations.Library
         private void AddUserToQuery(InternalItemsQuery query, User user, bool allowExternalContent = true)
         {
             if (query.AncestorIds.Length == 0 &&
-                query.ParentId.Equals(Guid.Empty) &&
+                query.ParentId.Equals(default) &&
                 query.ChannelIds.Count == 0 &&
                 query.TopParentIds.Length == 0 &&
                 string.IsNullOrEmpty(query.AncestorWithPresentationUniqueKey) &&
@@ -1540,7 +1540,7 @@ namespace Emby.Server.Implementations.Library
                 }
 
                 // Translate view into folders
-                if (!view.DisplayParentId.Equals(Guid.Empty))
+                if (!view.DisplayParentId.Equals(default))
                 {
                     var displayParent = GetItemById(view.DisplayParentId);
                     if (displayParent != null)
@@ -1551,7 +1551,7 @@ namespace Emby.Server.Implementations.Library
                     return Array.Empty<Guid>();
                 }
 
-                if (!view.ParentId.Equals(Guid.Empty))
+                if (!view.ParentId.Equals(default))
                 {
                     var displayParent = GetItemById(view.ParentId);
                     if (displayParent != null)
@@ -2153,7 +2153,7 @@ namespace Emby.Server.Implementations.Library
                 return null;
             }
 
-            while (!item.ParentId.Equals(Guid.Empty))
+            while (!item.ParentId.Equals(default))
             {
                 var parent = item.GetParent();
                 if (parent == null || parent is AggregateFolder)
@@ -2231,7 +2231,9 @@ namespace Emby.Server.Implementations.Library
             string viewType,
             string sortName)
         {
-            var parentIdString = parentId.Equals(Guid.Empty) ? null : parentId.ToString("N", CultureInfo.InvariantCulture);
+            var parentIdString = parentId.Equals(default)
+                ? null
+                : parentId.ToString("N", CultureInfo.InvariantCulture);
             var idValues = "38_namedview_" + name + user.Id.ToString("N", CultureInfo.InvariantCulture) + (parentIdString ?? string.Empty) + (viewType ?? string.Empty);
 
             var id = GetNewItemId(idValues, typeof(UserView));
@@ -2265,7 +2267,7 @@ namespace Emby.Server.Implementations.Library
 
             var refresh = isNew || DateTime.UtcNow - item.DateLastRefreshed >= _viewRefreshInterval;
 
-            if (!refresh && !item.DisplayParentId.Equals(Guid.Empty))
+            if (!refresh && !item.DisplayParentId.Equals(default))
             {
                 var displayParent = GetItemById(item.DisplayParentId);
                 refresh = displayParent != null && displayParent.DateLastSaved > item.DateLastRefreshed;
@@ -2332,7 +2334,7 @@ namespace Emby.Server.Implementations.Library
 
             var refresh = isNew || DateTime.UtcNow - item.DateLastRefreshed >= _viewRefreshInterval;
 
-            if (!refresh && !item.DisplayParentId.Equals(Guid.Empty))
+            if (!refresh && !item.DisplayParentId.Equals(default))
             {
                 var displayParent = GetItemById(item.DisplayParentId);
                 refresh = displayParent != null && displayParent.DateLastSaved > item.DateLastRefreshed;
@@ -2365,7 +2367,9 @@ namespace Emby.Server.Implementations.Library
                 throw new ArgumentNullException(nameof(name));
             }
 
-            var parentIdString = parentId.Equals(Guid.Empty) ? null : parentId.ToString("N", CultureInfo.InvariantCulture);
+            var parentIdString = parentId.Equals(default)
+                ? null
+                : parentId.ToString("N", CultureInfo.InvariantCulture);
             var idValues = "37_namedview_" + name + (parentIdString ?? string.Empty) + (viewType ?? string.Empty);
             if (!string.IsNullOrEmpty(uniqueId))
             {
@@ -2409,7 +2413,7 @@ namespace Emby.Server.Implementations.Library
 
             var refresh = isNew || DateTime.UtcNow - item.DateLastRefreshed >= _viewRefreshInterval;
 
-            if (!refresh && !item.DisplayParentId.Equals(Guid.Empty))
+            if (!refresh && !item.DisplayParentId.Equals(default))
             {
                 var displayParent = GetItemById(item.DisplayParentId);
                 refresh = displayParent != null && displayParent.DateLastSaved > item.DateLastRefreshed;

Emby.Server.Implementations/Library/MediaSourceManager.cs

@@ -514,10 +514,10 @@ namespace Emby.Server.Implementations.Library
             _logger.LogInformation("Live stream opened: {@MediaSource}", mediaSource);
             var clone = JsonSerializer.Deserialize<MediaSourceInfo>(json, _jsonOptions);
 
-            if (!request.UserId.Equals(Guid.Empty))
+            if (!request.UserId.Equals(default))
             {
                 var user = _userManager.GetUserById(request.UserId);
-                var item = request.ItemId.Equals(Guid.Empty)
+                var item = request.ItemId.Equals(default)
                     ? null
                     : _libraryManager.GetItemById(request.ItemId);
                 SetDefaultAudioAndSubtitleStreamIndexes(item, clone, user);

Emby.Server.Implementations/Library/MusicManager.cs

@@ -80,7 +80,7 @@ namespace Emby.Server.Implementations.Library
                 {
                     return Guid.Empty;
                 }
-            }).Where(i => !i.Equals(Guid.Empty)).ToArray();
+            }).Where(i => !i.Equals(default)).ToArray();
 
             return GetInstantMixFromGenreIds(genreIds, user, dtoOptions);
         }

Emby.Server.Implementations/Library/SearchEngine.cs

@@ -30,7 +30,7 @@ namespace Emby.Server.Implementations.Library
         public QueryResult<SearchHintInfo> GetSearchHints(SearchQuery query)
         {
             User user = null;
-            if (query.UserId != Guid.Empty)
+            if (!query.UserId.Equals(default))
             {
                 user = _userManager.GetUserById(query.UserId);
             }
@@ -168,10 +168,10 @@ namespace Emby.Server.Implementations.Library
                 {
                     Fields = new ItemFields[]
                     {
-                         ItemFields.AirTime,
-                         ItemFields.DateCreated,
-                         ItemFields.ChannelInfo,
-                         ItemFields.ParentId
+                        ItemFields.AirTime,
+                        ItemFields.DateCreated,
+                        ItemFields.ChannelInfo,
+                        ItemFields.ParentId
                     }
                 }
             };
@@ -180,12 +180,12 @@ namespace Emby.Server.Implementations.Library
 
             if (searchQuery.IncludeItemTypes.Length == 1 && searchQuery.IncludeItemTypes[0] == BaseItemKind.MusicArtist)
             {
-                if (!searchQuery.ParentId.Equals(Guid.Empty))
+                if (!searchQuery.ParentId.Equals(default))
                 {
                     searchQuery.AncestorIds = new[] { searchQuery.ParentId };
+                    searchQuery.ParentId = Guid.Empty;
                 }
 
-                searchQuery.ParentId = Guid.Empty;
                 searchQuery.IncludeItemsByName = true;
                 searchQuery.IncludeItemTypes = Array.Empty<BaseItemKind>();
                 mediaItems = _libraryManager.GetAllArtists(searchQuery).Items.Select(i => i.Item).ToList();

Emby.Server.Implementations/Library/UserViewManager.cs

@@ -142,7 +142,7 @@ namespace Emby.Server.Implementations.Library
 
                     if (index == -1
                         && i is UserView view
-                        && view.DisplayParentId != Guid.Empty)
+                        && !view.DisplayParentId.Equals(default))
                     {
                         index = Array.IndexOf(orders, view.DisplayParentId);
                     }
@@ -214,7 +214,7 @@ namespace Emby.Server.Implementations.Library
                 }
                 else
                 {
-                    var current = list.FirstOrDefault(i => i.Item1 != null && i.Item1.Id == container.Id);
+                    var current = list.FirstOrDefault(i => i.Item1 != null && i.Item1.Id.Equals(container.Id));
 
                     if (current != null)
                     {
@@ -244,7 +244,7 @@ namespace Emby.Server.Implementations.Library
 
             var parents = new List<BaseItem>();
 
-            if (!parentId.Equals(Guid.Empty))
+            if (!parentId.Equals(default))
             {
                 var parentItem = _libraryManager.GetItemById(parentId);
                 if (parentItem is Channel)