Use new model to clear results & Fix clear existing results when using IResultUpdate

Flow.Launcher/ViewModel/MainViewModel.cs

@@ -37,6 +37,9 @@
         private string _queryTextBeforeLeaveResults;
         private string _ignoredQueryText; // Used to ignore query text change when switching between context menu and query results
 
+        private readonly object _shouldClearExistingResultsLock = new();
+        private bool _shouldClearExistingResults;
+
         private readonly FlowLauncherJsonStorage<History> _historyItemsStorage;
         private readonly FlowLauncherJsonStorage<UserSelectedRecord> _userSelectedRecordStorage;
         private readonly FlowLauncherJsonStorageTopMostRecord _topMostRecord;
@@ -1434,11 +1437,19 @@
 
                 // Indicate if to clear existing results so to show only ones from plugins with action keywords
                 var shouldClearExistingResults = ShouldClearExistingResultsForQuery(query, currentIsHomeQuery);
+                if (shouldClearExistingResults)
+                {
+                    // Setup the flag to clear existing results so that ResultsViewModel.NewResults will handle in the next update
+                    lock (_shouldClearExistingResultsLock)
+                    {
+                        _shouldClearExistingResults = true;
+                    }
+                }
                 _lastQuery = query;
                 _previousIsHomeQuery = currentIsHomeQuery;
 
                 if (!_resultsUpdateChannelWriter.TryWrite(new ResultsForUpdate(resultsCopy, plugin.Metadata, query,
-                    token, reSelect, shouldClearExistingResults)))
+                    token, reSelect)))
                 {
                     App.API.LogError(ClassName, "Unable to add item to Result Update Queue");
                 }
@@ -1457,11 +1468,19 @@
 
                 // Indicate if to clear existing results so to show only ones from plugins with action keywords
                 var shouldClearExistingResults = ShouldClearExistingResultsForQuery(query, currentIsHomeQuery);
+                if (shouldClearExistingResults)
+                {
+                    // Setup the flag to clear existing results so that ResultsViewModel.NewResults will handle in the next update
+                    lock (_shouldClearExistingResultsLock)
+                    {
+                        _shouldClearExistingResults = true;
+                    }
+                }
                 _lastQuery = query;
                 _previousIsHomeQuery = currentIsHomeQuery;
 
                 if (!_resultsUpdateChannelWriter.TryWrite(new ResultsForUpdate(results, _historyMetadata, query,
-                    token, reSelect, shouldClearExistingResults)))
+                    token, reSelect)))
                 {
                     App.API.LogError(ClassName, "Unable to add item to Result Update Queue");
                 }
@@ -1696,6 +1715,20 @@
             return selected;
         }
 
+        internal bool CheckShouldClearExistingResultsAndReset()
+        {
+            lock (_shouldClearExistingResultsLock)
+            {
+                if (_shouldClearExistingResults)
+                {
+                    _shouldClearExistingResults = false;
+                    return true;
+                }
+
+                return false;
+            }
+        }
+
         #endregion
 
         #region Hotkey
@@ -1842,7 +1875,7 @@
             VisibilityChanged?.Invoke(this, new VisibilityChangedEventArgs { IsVisible = false });
         }
 
 #pragma warning restore VSTHRD100 // Avoid async void methods
 
         /// <summary>
         /// Save history, user selected records and top most records

Flow.Launcher/ViewModel/ResultsForUpdate.cs

@@ -9,8 +9,7 @@ public record struct ResultsForUpdate(
         PluginMetadata Metadata,
         Query Query,
         CancellationToken Token,
-        bool ReSelectFirstResult = true,
-        bool shouldClearExistingResults = false)
+        bool ReSelectFirstResult = true)
     {
         public string ID { get; } = Metadata.ID;
     }

Flow.Launcher/ViewModel/ResultsViewModel.cs

@@ -187,11 +187,12 @@ public void AddResults(List<Result> newRawResults, string resultId)
         /// </summary>
         public void AddResults(ICollection<ResultsForUpdate> resultsForUpdates, CancellationToken token, bool reselect = true)
         {
-            var newResults = NewResults(resultsForUpdates);
-
             if (token.IsCancellationRequested)
                 return;
 
+            // Since NewResults may need to clear existing results, do not check token cancellation after this point
+            var newResults = NewResults(resultsForUpdates);
+
             UpdateResults(newResults, reselect, token);
         }
 
@@ -244,7 +245,8 @@ private List<ResultViewModel> NewResults(ICollection<ResultsForUpdate> resultsFo
 
             var newResults = resultsForUpdates.SelectMany(u => u.Results, (u, r) => new ResultViewModel(r, _settings));
 
-            if (resultsForUpdates.Any(x => x.shouldClearExistingResults))
+            // If mainVM has flag to clear existing results, handle it here
+            if (_mainVM != null && _mainVM.CheckShouldClearExistingResultsAndReset())
             {
                 App.API.LogDebug("NewResults", $"Existing results are cleared for query");
                 return newResults.OrderByDescending(rv => rv.Result.Score).ToList();
@@ -293,34 +295,32 @@ public class ResultCollection : List<ResultViewModel>, INotifyCollectionChanged
         {
             private long editTime = 0;
 
-            private CancellationToken _token;
-
             public event NotifyCollectionChangedEventHandler CollectionChanged;
 
             protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
             {
                 CollectionChanged?.Invoke(this, e);
             }
 
-            public void BulkAddAll(List<ResultViewModel> resultViews)
+            private void BulkAddAll(List<ResultViewModel> resultViews, CancellationToken token = default)
             {
                 AddRange(resultViews);
 
                 // can return because the list will be cleared next time updated, which include a reset event
-                if (_token.IsCancellationRequested)
+                if (token.IsCancellationRequested)
                     return;
 
                 // manually update event
                 // wpf use DirectX / double buffered already, so just reset all won't cause ui flickering
                 OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
             }
 
-            private void AddAll(List<ResultViewModel> Items)
+            private void AddAll(List<ResultViewModel> Items, CancellationToken token = default)
             {
                 for (int i = 0; i < Items.Count; i++)
                 {
                     var item = Items[i];
-                    if (_token.IsCancellationRequested)
+                    if (token.IsCancellationRequested)
                         return;
                     Add(item);
                     OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item, i));
@@ -342,21 +342,30 @@ public void RemoveAll(int Capacity = 512)
             /// <param name="newItems"></param>
             public void Update(List<ResultViewModel> newItems, CancellationToken token = default)
             {
-                _token = token;
-                if (Count == 0 && newItems.Count == 0 || _token.IsCancellationRequested)
+                // Since NewResults may need to clear existing results, so we cannot check token cancellation here
+                if (Count == 0 && newItems.Count == 0)
                     return;
 
                 if (editTime < 10 || newItems.Count < 30)
                 {
                     if (Count != 0) RemoveAll(newItems.Count);
-                    AddAll(newItems);
+
+                    // After results are removed, we need to check the token cancellation
+                    // so that we will not add new items from the cancelled queries
+                    if (token.IsCancellationRequested) return;
+
+                    AddAll(newItems, token);
                     editTime++;
-                    return;
                 }
                 else
                 {
                     Clear();
-                    BulkAddAll(newItems);
+
+                    // After results are removed, we need to check the token cancellation
+                    // so that we will not add new items from the cancelled queries
+                    if (token.IsCancellationRequested) return;
+
+                    BulkAddAll(newItems, token);
                     if (Capacity > 8000 && newItems.Count < 3000)
                     {
                         Capacity = newItems.Count;