Merge pull request #2584 from Nexus-Mods/fix-large-operations-perfrom…

…ance Use SelectAwait in DiagnosticManager and fix a bunch of exceptions
Nexus-Mods · Feb 3, 2025 · 5c2879e · 5c2879e
2 parents e50328d + 6e80772
commit 5c2879e
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Showing 6 changed files with 68 additions and 34 deletions.
diff --git a/src/NexusMods.App.UI/Extensions/EnumerableExtensions.cs b/src/NexusMods.App.UI/Extensions/EnumerableExtensions.cs
@@ -32,7 +32,7 @@ public static ReadOnlyObservableCollection<T> ToReadOnlyObservableCollection<T>(
         return new ReadOnlyObservableCollection<T>(source.ToObservableCollection());
     }
 
-    public static Optional<TItem> MaxByOptional<TItem, TValue>(this IEnumerable<TItem> source, Func<TItem, TValue> selector)
+    public static Optional<TItem> OptionalMaxBy<TItem, TValue>(this IEnumerable<TItem> source, Func<TItem, TValue> selector)
         where TItem : notnull
         where TValue : IComparable<TValue>
     {
@@ -61,4 +61,34 @@ public static Optional<TItem> MaxByOptional<TItem, TValue>(this IEnumerable<TIte
 
         return maxItem;
     }
+
+    public static Optional<TItem> OptionalMinBy<TItem, TValue>(this IEnumerable<TItem> source, Func<TItem, TValue> selector)
+        where TItem : notnull
+        where TValue : IComparable<TValue>
+    {
+        var minItem = Optional<TItem>.None;
+        var minValue = Optional<TValue>.None;
+
+        foreach (var item in source)
+        {
+            if (!minItem.HasValue)
+            {
+                minItem = item;
+                minValue = selector(item);
+                continue;
+            }
+
+            var value = selector(item);
+            var result = value.CompareTo(minValue.Value);
+
+            // Smaller than zero: value comes before minValue
+            if (result < 0)
+            {
+                minItem = item;
+                minValue = value;
+            }
+        }
+
+        return minItem;
+    }
 }
diff --git a/src/NexusMods.App.UI/Pages/CollectionDownload/CollectionDownloadViewModel.cs b/src/NexusMods.App.UI/Pages/CollectionDownload/CollectionDownloadViewModel.cs
@@ -361,7 +361,7 @@ public CollectionDownloadViewModel(
                 .Subscribe(this, static (newerRevisions, self) =>
                 {
                     self.IsUpdateAvailable.Value = newerRevisions.Length > 0;
-                    self.NewestRevisionNumber.Value = newerRevisions.First();
+                    self.NewestRevisionNumber.Value = newerRevisions.FirstOrOptional(_ => true);
                 }).AddTo(disposables);
 
             R3.Observable.Return(collectionJsonFile)

diff --git a/src/NexusMods.App.UI/Pages/ILibraryDataProvider.cs b/src/NexusMods.App.UI/Pages/ILibraryDataProvider.cs
@@ -6,6 +6,7 @@
 using NexusMods.Abstractions.Library.Models;
 using NexusMods.Abstractions.Loadouts;
 using NexusMods.App.UI.Controls;
+using NexusMods.App.UI.Extensions;
 using NexusMods.App.UI.Pages.LibraryPage;
 using NexusMods.MnemonicDB.Abstractions;
 using NexusMods.MnemonicDB.Abstractions.Query;
@@ -58,8 +59,8 @@ public static void AddInstalledDateComponent(
                 if (query.Count == 0) return Optional<DateTimeOffset>.None;
 
                 return query.Items
-                    .Select(static item => item.GetCreatedAt())
-                    .Min();
+                        .Select(static item => item.GetCreatedAt())
+                        .OptionalMinBy(item => item);
             });
 
         itemModel.AddObservable(

diff --git a/src/NexusMods.App.UI/Pages/ILoadoutDataProvider.cs b/src/NexusMods.App.UI/Pages/ILoadoutDataProvider.cs
@@ -5,6 +5,7 @@
 using NexusMods.Abstractions.Loadouts;
 using NexusMods.Abstractions.Loadouts.Extensions;
 using NexusMods.App.UI.Controls;
+using NexusMods.App.UI.Extensions;
 using NexusMods.App.UI.Pages.LoadoutPage;
 using NexusMods.MnemonicDB.Abstractions;
 using NexusMods.MnemonicDB.Abstractions.DatomIterators;
@@ -87,7 +88,8 @@ public static void AddDateComponent(
         var dateObservable = linkedItemsObservable
             .QueryWhenChanged(query => query.Items
                 .Select(static item => item.GetCreatedAt())
-                .Min()
+                .OptionalMinBy(item => item)
+                .ValueOr(DateTimeOffset.MinValue)
             );
 
         parentItemModel.Add(SharedColumns.InstalledDate.ComponentKey, new DateComponent(

diff --git a/src/NexusMods.App.UI/Pages/NexusModsDataProvider.cs b/src/NexusMods.App.UI/Pages/NexusModsDataProvider.cs
@@ -244,7 +244,7 @@ private CompositeItemModel<EntityId> ToLibraryItemModel(NexusModsModPageMetadata
         // Downloaded date: most recent downloaded file date
         var downloadedDateObservable = libraryItems
             .TransformImmutable(static item => item.GetCreatedAt())
-            .QueryWhenChanged(query => query.Items.Max());
+            .QueryWhenChanged(query => query.Items.OptionalMaxBy(item => item).ValueOr(DateTimeOffset.MinValue));
 
         parentItemModel.Add(LibraryColumns.DownloadedDate.ComponentKey, new DateComponent(
             initialValue: modPage.GetCreatedAt(),
@@ -263,7 +263,7 @@ private CompositeItemModel<EntityId> ToLibraryItemModel(NexusModsModPageMetadata
             })
             .QueryWhenChanged(static query =>
             {
-                var max = query.Items.MaxByOptional(static tuple => tuple.parsedVersion.ValueOr(new NuGetVersion(0, 0, 0)));
+                var max = query.Items.OptionalMaxBy(static tuple => tuple.parsedVersion.ValueOr(new NuGetVersion(0, 0, 0)));
                 if (!max.HasValue) return string.Empty;
                 return max.Value.rawVersion;
             });

diff --git a/src/NexusMods.DataModel/Diagnostics/DiagnosticManager.cs b/src/NexusMods.DataModel/Diagnostics/DiagnosticManager.cs
@@ -1,4 +1,3 @@
-using System.Collections.Concurrent;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
@@ -9,10 +8,9 @@
 using NexusMods.Abstractions.Diagnostics.Emitters;
 using NexusMods.Abstractions.Games;
 using NexusMods.Abstractions.Loadouts;
-using NexusMods.Extensions.BCL;
 using NexusMods.MnemonicDB.Abstractions;
-using NexusMods.MnemonicDB.Abstractions.Query;
-using Observable = R3.Observable;
+using R3;
+using CompositeDisposable = R3.CompositeDisposable;
 
 namespace NexusMods.DataModel.Diagnostics;
 
@@ -23,7 +21,7 @@ internal sealed class DiagnosticManager : IDiagnosticManager
     private readonly ILogger<DiagnosticManager> _logger;
 
     private static readonly object Lock = new();
-    private readonly SourceCache<IConnectableObservable<Diagnostic[]>, LoadoutId> _observableCache = new(_ => throw new NotSupportedException());
+    private readonly SourceCache<ConnectableObservable<Diagnostic[]>, LoadoutId> _observableCache = new(_ => throw new NotSupportedException());
 
     private bool _isDisposed;
     private readonly CompositeDisposable _compositeDisposable = new();
@@ -42,35 +40,38 @@ public IObservable<Diagnostic[]> GetLoadoutDiagnostics(LoadoutId loadoutId)
         lock (Lock)
         {
             var existingObservable = _observableCache.Lookup(loadoutId);
-            if (existingObservable.HasValue) return existingObservable.Value;
+            if (existingObservable.HasValue) return existingObservable.Value.AsSystemObservable();
 
             var connectableObservable = Loadout.RevisionsWithChildUpdates(_connection, loadoutId)
-                .Throttle(dueTime: TimeSpan.FromMilliseconds(250))
-                .SelectMany(async _ =>
-                {
-                    var db = _connection.Db;
-                    var loadout = Loadout.Load(db, loadoutId);
-                    if (!loadout.IsValid()) return [];
-
-                    try
+                .ToObservable()
+                .Debounce(TimeSpan.FromMilliseconds(250))
+                .SelectAwait(async (_, cancellationToken) =>
                     {
-                        // TODO: cancellation token
-                        // TODO: optimize this a bit so we don't load the model twice, we have the datoms above, we should be able to use them
+                        var db = _connection.Db;
+                        var loadout = Loadout.Load(db, loadoutId);
+                        if (!loadout.IsValid()) return [];
 
-                        var cancellationToken = CancellationToken.None;
-                        return await GetLoadoutDiagnostics(loadout, cancellationToken);
-                    }
-                    catch (Exception e)
-                    {
-                        _logger.LogError(e, "Exception while diagnosing loadout {Loadout}", loadout.Name);
-                        return [];
-                    }
-                })
+                        try
+                        {
+                            return await GetLoadoutDiagnostics(loadout, cancellationToken);
+                        }
+                        catch (OperationCanceledException)
+                        {
+                            return [];
+                        }
+                        catch (Exception e)
+                        {
+                            _logger.LogError(e, "Exception while diagnosing loadout {Loadout}", loadout.Name);
+                            return [];
+                        }
+                    },
+                    AwaitOperation.Switch
+                )
                 .Replay(bufferSize: 1);
 
             _compositeDisposable.Add(connectableObservable.Connect());
             _observableCache.Edit(updater => updater.AddOrUpdate(connectableObservable, loadoutId));
-            return connectableObservable;
+            return connectableObservable.AsSystemObservable();
         }
     }
 
@@ -96,7 +97,7 @@ await Parallel.ForEachAsync(diagnosticEmitters.OfType<ILoadoutDiagnosticEmitter>
                         }
                     }
                 }
-                catch (TaskCanceledException)
+                catch (OperationCanceledException)
                 {
                     // ignore
                 }