Add snapshot translation for HunkRangeInfo, used when updating diff p…

…ositions after an edit
allenk · Feb 6, 2013 · b9bf835 · b9bf835
1 parent 5e7fbcc
commit b9bf835
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Showing 2 changed files with 47 additions and 4 deletions.
diff --git a/Diff/HunkRangeInfo.cs b/Diff/HunkRangeInfo.cs
@@ -28,6 +28,13 @@ public HunkRangeInfo(ITextSnapshot snapshot, Edit edit, RawText originalText, Ra
             _originalText = originalText.GetString(edit.GetBeginA(), edit.GetEndA(), true).Split('\n').Select(i => i.TrimEnd('\r')).ToList();
         }
 
+        private HunkRangeInfo(ITextSnapshot snapshot, Edit edit, List<string> originalText)
+        {
+            _snapshot = snapshot;
+            _edit = edit;
+            _originalText = originalText;
+        }
+
         public ITextSnapshot Snapshot
         {
             get
@@ -83,5 +90,39 @@ public bool IsDeletion
                 return _edit.GetType() == Edit.Type.DELETE;
             }
         }
+
+        public HunkRangeInfo TranslateTo(ITextSnapshot snapshot)
+        {
+            if (snapshot == null)
+                throw new ArgumentNullException("snapshot");
+
+            if (snapshot == _snapshot)
+                return this;
+
+            if (IsDeletion)
+            {
+                // track a point
+                ITextSnapshotLine line = _snapshot.GetLineFromLineNumber(_edit.GetBeginB());
+                ITrackingPoint trackingPoint = _snapshot.CreateTrackingPoint(line.Start, PointTrackingMode.Negative);
+
+                SnapshotPoint updated = trackingPoint.GetPoint(snapshot);
+                int updatedLineNumber = updated.GetContainingLine().LineNumber;
+                Edit updatedEdit = new Edit(_edit.GetBeginA(), _edit.GetEndA(), updatedLineNumber, updatedLineNumber);
+                return new HunkRangeInfo(snapshot, updatedEdit, _originalText);
+            }
+            else
+            {
+                // track a span
+                ITextSnapshotLine startLine = _snapshot.GetLineFromLineNumber(_edit.GetBeginB());
+                ITextSnapshotLine endLine = _snapshot.GetLineFromLineNumber(_edit.GetEndB() - 1);
+                ITrackingSpan trackingSpan = _snapshot.CreateTrackingSpan(new SnapshotSpan(startLine.Start, endLine.EndIncludingLineBreak), SpanTrackingMode.EdgeInclusive);
+
+                SnapshotSpan updated = trackingSpan.GetSpan(snapshot);
+                int updatedStartLineNumber = updated.Start.GetContainingLine().LineNumber;
+                int updatedEndLineNumber = updated.End.GetContainingLine().LineNumber;
+                Edit updatedEdit = new Edit(_edit.GetBeginA(), _edit.GetEndA(), updatedStartLineNumber, updatedEndLineNumber);
+                return new HunkRangeInfo(snapshot, updatedEdit, _originalText);
+            }
+        }
     }
 }
diff --git a/Diff/ViewModel/DiffViewModel.cs b/Diff/ViewModel/DiffViewModel.cs
@@ -84,8 +84,10 @@ private void UpdateDimensions()
             if (_reverted)
                 return;
 
-            ITextSnapshotLine startLine = _textView.TextSnapshot.GetLineFromLineNumber(_hunkRangeInfo.NewHunkRange.StartingLineNumber);
-            ITextSnapshotLine endLine = _textView.TextSnapshot.GetLineFromLineNumber(_hunkRangeInfo.NewHunkRange.StartingLineNumber + _hunkRangeInfo.NewHunkRange.NumberOfLines - 1);
+            HunkRangeInfo hunkRangeInfo = _hunkRangeInfo.TranslateTo(_textView.TextBuffer.CurrentSnapshot);
+
+            ITextSnapshotLine startLine = _textView.TextSnapshot.GetLineFromLineNumber(hunkRangeInfo.NewHunkRange.StartingLineNumber);
+            ITextSnapshotLine endLine = _textView.TextSnapshot.GetLineFromLineNumber(hunkRangeInfo.NewHunkRange.StartingLineNumber + hunkRangeInfo.NewHunkRange.NumberOfLines - 1);
             if (startLine != null && endLine != null)
             {
                 IWpfTextViewLine startLineView = _textView.GetTextViewLineContainingBufferPosition(startLine.Start);
@@ -171,7 +173,7 @@ private void UpdateDimensions()
 
                 if (stopBottom <= startTop)
                 {
-                    if (_hunkRangeInfo.IsDeletion)
+                    if (hunkRangeInfo.IsDeletion)
                     {
                         double center = (startTop + stopBottom) / 2.0;
                         Top = center - (_textView.LineHeight / 2.0);
@@ -180,7 +182,7 @@ private void UpdateDimensions()
                     }
                     else
                     {
-                        // shouldn't be reachable, but definitely hide if this is the case
+                        // could be reachable if translation changes an addition to empty
                         IsVisible = false;
                     }