1 files changed, 125 insertions, 0 deletions
diff --git a/src/Text/Impl/TextModel/PersistentSpanSet.cs b/src/Text/Impl/TextModel/PersistentSpanSet.cs
new file mode 100644
index 0000000..8370eeb
--- /dev/null
+++ b/src/Text/Impl/TextModel/PersistentSpanSet.cs
@@ -0,0 +1,125 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// This file contain implementations details that are subject to change without notice.
+// Use at your own risk.
+//
+namespace Microsoft.VisualStudio.Text.Implementation
+{
+    using System;
+    using System.Collections.Generic;
+
+    sealed class PersistentSpanSet : IDisposable
+    {
+        internal FileNameKey FileKey;
+        internal ITextDocument Document;
+        internal readonly HashSet<PersistentSpan> Spans = new HashSet<PersistentSpan>();
+        private readonly PersistentSpanFactory Factory;
+
+        private ITextSnapshot _savedSnapshot = null;
+
+        internal PersistentSpanSet(FileNameKey filePath, ITextDocument document, PersistentSpanFactory factory)
+        {
+            this.FileKey = filePath;
+            this.Document = document;
+            this.Factory = factory;
+
+            if (document != null)
+            {
+                document.FileActionOccurred += this.OnFileActionOccurred;
+            }
+        }
+
+        public void Dispose()
+        {
+            Assumes.True(this.Spans.Count == 0);
+
+            if (this.Document != null)
+            {
+                this.Document.FileActionOccurred -= this.OnFileActionOccurred;
+                this.Document = null;
+            }
+        }
+
+        internal PersistentSpan Create(int startLine, int startIndex, int endLine, int endIndex, SpanTrackingMode trackingMode)
+        {
+            PersistentSpan persistentSpan = new PersistentSpan(startLine, startIndex, endLine, endIndex, trackingMode, this);
+            this.Spans.Add(persistentSpan);
+            return persistentSpan;
+        }
+
+        internal PersistentSpan Create(Span span, SpanTrackingMode trackingMode)
+        {
+            var persistentSpan = new PersistentSpan(span, trackingMode, this);
+            this.Spans.Add(persistentSpan);
+            return persistentSpan;
+        }
+
+        internal PersistentSpan Create(ITextSnapshot snapshot, int startLine, int startIndex, int endLine, int endIndex, SpanTrackingMode trackingMode)
+        {
+            var start = PersistentSpan.LineIndexToSnapshotPoint(startLine, startIndex, snapshot);
+            var end = PersistentSpan.LineIndexToSnapshotPoint(endLine, endIndex, snapshot);
+            if (end < start)
+            {
+                end = start;
+            }
+
+            return this.Create(new SnapshotSpan(start, end), trackingMode);
+        }
+
+        internal PersistentSpan Create(SnapshotSpan span, SpanTrackingMode trackingMode)
+        {
+            var persistentSpan = new PersistentSpan(span, trackingMode, this);
+            this.Spans.Add(persistentSpan);
+            return persistentSpan;
+        }
+
+        internal void Delete(PersistentSpan span)
+        {
+            this.Factory.Delete(this, span);
+        }
+
+        internal void DocumentReopened(ITextDocument document)
+        {
+            Requires.NotNull(document, nameof(document));
+            Assumes.Null(this.Document);
+
+            this.Document = document;
+            document.FileActionOccurred += this.OnFileActionOccurred;
+
+            foreach (var s in this.Spans)
+            {
+                s.DocumentReopened();
+            }
+        }
+
+        internal void DocumentClosed()
+        {
+            Assumes.NotNull(this.Document);
+
+            this.FileKey = new FileNameKey(this.Document.FilePath);
+
+            foreach (var s in this.Spans)
+            {
+                s.DocumentClosed(_savedSnapshot);
+            }
+
+            this.Document.FileActionOccurred -= this.OnFileActionOccurred;
+            this.Document = null;
+        }
+
+        private void OnFileActionOccurred(object sender, TextDocumentFileActionEventArgs e)
+        {
+            if (e.FileActionType == FileActionTypes.ContentSavedToDisk)
+            {
+                _savedSnapshot = this.Document.TextBuffer.CurrentSnapshot;
+            }
+            else if (e.FileActionType == FileActionTypes.DocumentRenamed)
+            {
+                this.FileKey = new FileNameKey(this.Document.FilePath);
+                this.Factory.DocumentRenamed(this);
+            }
+        }
+    }
+}