Forced parsing and tagging off the main thread

[release]
madskristensen · Jan 2, 2022 · d1f1b39 · d1f1b39
1 parent dc511b0
commit d1f1b39
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Showing 2 changed files with 47 additions and 25 deletions.
diff --git a/src/Language/TokenTagger.cs b/src/Language/TokenTagger.cs
@@ -9,6 +9,7 @@
 using Microsoft.VisualStudio.Text;
 using Microsoft.VisualStudio.Text.Adornments;
 using Microsoft.VisualStudio.Text.Tagging;
+using Microsoft.VisualStudio.Threading;
 using Microsoft.VisualStudio.Utilities;
 
 namespace PkgdefLanguage
@@ -37,7 +38,12 @@ internal TokenTagger(ITextBuffer buffer)
             _document = buffer.GetDocument();
             _document.Processed += ReParse;
             _tagsCache = new Dictionary<ParseItem, ITagSpan<TokenTag>>();
-            ReParse();
+
+            ThreadHelper.JoinableTaskFactory.RunAsync(async () =>
+            {
+                await TaskScheduler.Default;
+                ReParse();
+            }).FireAndForget();
         }
 
         public IEnumerable<ITagSpan<TokenTag>> GetTags(NormalizedSnapshotSpanCollection spans)
@@ -47,26 +53,31 @@ public IEnumerable<ITagSpan<TokenTag>> GetTags(NormalizedSnapshotSpanCollection
 
         private void ReParse(object sender = null, EventArgs e = null)
         {
-            ThreadHelper.JoinableTaskFactory.StartOnIdle(() =>
-            {
-                Dictionary<ParseItem, ITagSpan<TokenTag>> list = new();
+            // Make sure this is running on a background thread.
+            ThreadHelper.ThrowIfOnUIThread();
 
-                foreach (ParseItem item in _document.Items)
-                {
-                    AddTagToList(list, item);
+            Dictionary<ParseItem, ITagSpan<TokenTag>> list = new();
 
-                    foreach (ParseItem variable in item.References)
-                    {
-                        AddTagToList(list, variable);
-                    }
+            foreach (ParseItem item in _document.Items)
+            {
+                if (_document.IsProcessing)
+                {
+                    // Abort and wait for the next parse event to finish
+                    return;
                 }
 
-                _tagsCache = list;
+                AddTagToList(list, item);
+
+                foreach (ParseItem variable in item.References)
+                {
+                    AddTagToList(list, variable);
+                }
+            }
 
-                SnapshotSpan span = new(_buffer.CurrentSnapshot, 0, _buffer.CurrentSnapshot.Length);
-                TagsChanged?.Invoke(this, new SnapshotSpanEventArgs(span));
+            _tagsCache = list;
 
-            }, VsTaskRunContext.UIThreadIdlePriority);
+            SnapshotSpan span = new(_buffer.CurrentSnapshot, 0, _buffer.CurrentSnapshot.Length);
+            TagsChanged?.Invoke(this, new SnapshotSpanEventArgs(span));
         }
 
         private void AddTagToList(Dictionary<ParseItem, ITagSpan<TokenTag>> list, ParseItem item)

diff --git a/src/Parser/Document.cs b/src/Parser/Document.cs
@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Text;
+using Microsoft.VisualStudio.Threading;
 
 namespace PkgdefLanguage
 {
@@ -59,23 +61,32 @@ public static Document FromLines(params string[] lines)
             return doc;
         }
 
-        public Task ProcessAsync()
+        public async Task ProcessAsync()
         {
             IsProcessing = true;
+            var success = false;
 
-            return Task.Run(() =>
+            await TaskScheduler.Default;
+
+            try
             {
-                try
-                {
-                    Parse();
-                    ValidateDocument();
-                }
-                finally
+                Parse();
+                ValidateDocument();
+                success = true;
+            }
+            catch (Exception ex)
+            {
+                await ex.LogAsync();
+            }
+            finally
+            {
+                IsProcessing = false;
+
+                if (success)
                 {
-                    IsProcessing = false;
                     Processed?.Invoke(this, EventArgs.Empty);
                 }
-            });
+            }
         }
 
         public ParseItem FindItemFromPosition(int position)