/// <summary>
/// Updates the start and end offsets of all segments stored in this collection.
/// </summary>
/// <param name="change">OffsetChangeMapEntry instance describing the change to the document.</param>
public void UpdateOffsets(OffsetChangeMapEntry change)
{
if (isConnectedToDocument)
{
throw new InvalidOperationException("This TextSegmentCollection will automatically update offsets; do not call UpdateOffsets manually!");
}
UpdateOffsetsInternal(change);
CheckProperties();
}
void UpdateOffsetsInternal(OffsetChangeMapEntry change)
{
// Special case pure insertions, because they don't always cause a text segment to increase in size when the replaced region
// is inside a segment (when offset is at start or end of a text semgent).
if (change.RemovalLength == 0)
{
InsertText(change.Offset, change.InsertionLength);
}
else
{
ReplaceText(change);
}
}
void ReplaceText(OffsetChangeMapEntry change)
{
Debug.Assert(change.RemovalLength > 0);
int offset = change.Offset;
foreach (TextSegment segment in FindOverlappingSegments(offset, change.RemovalLength))
{
if (segment.StartOffset <= offset)
{
if (segment.EndOffset >= offset + change.RemovalLength)
{
// Replacement inside segment: adjust segment length
segment.Length += change.InsertionLength - change.RemovalLength;
}
else
{
// Replacement starting inside segment and ending after segment end: set segment end to removal position
//segment.EndOffset = offset;
segment.Length = offset - segment.StartOffset;
}
}
else
{
// Replacement starting in front of text segment and running into segment.
// Keep segment.EndOffset constant and move segment.StartOffset to the end of the replacement
int remainingLength = segment.EndOffset - (offset + change.RemovalLength);
RemoveSegment(segment);
segment.StartOffset = offset + change.RemovalLength;
segment.Length = Math.Max(0, remainingLength);
AddSegment(segment);
}
}
// move start offsets of all segments > offset
TextSegment node = FindFirstSegmentWithStartAfter(offset + 1);
if (node != null)
{
Debug.Assert(node.nodeLength >= change.RemovalLength);
node.nodeLength += change.InsertionLength - change.RemovalLength;
UpdateAugmentedData(node);
}
}
public void HandleTextChange(OffsetChangeMapEntry entry, DelayedEvents delayedEvents)
{
//Log("HandleTextChange(" + entry + ")");
if (entry.RemovalLength == 0)
{
// This is a pure insertion.
// Unlike a replace with removal, a pure insertion can result in nodes at the same location
// to split depending on their MovementType.
// Thus, we handle this case on a separate code path
// (the code below looks like it does something similar, but it can only split
// the set of deletion survivors, not all nodes at an offset)
InsertText(entry.Offset, entry.InsertionLength, entry.DefaultAnchorMovementIsBeforeInsertion);
return;
}
// When handling a replacing text change, we need to:
// - find all anchors in the deleted segment and delete them / move them to the appropriate
// surviving side.
// - adjust the segment size between the left and right side
int offset = entry.Offset;
int remainingRemovalLength = entry.RemovalLength;
// if the text change is happening after the last anchor, we don't have to do anything
if (root == null || offset >= root.totalLength)
{
return;
}
TextAnchorNode node = FindNode(ref offset);
TextAnchorNode firstDeletionSurvivor = null;
// go forward through the tree and delete all nodes in the removal segment
while (node != null && offset + remainingRemovalLength > node.length)
{
TextAnchor anchor = (TextAnchor)node.Target;
if (anchor != null && (anchor.SurviveDeletion || entry.RemovalNeverCausesAnchorDeletion))
{
if (firstDeletionSurvivor == null)
{
firstDeletionSurvivor = node;
}
// This node should be deleted, but it wants to survive.
// We'll just remove the deleted length segment, so the node will be positioned
// in front of the removed segment.
remainingRemovalLength -= node.length - offset;
node.length = offset;
offset = 0;
UpdateAugmentedData(node);
node = node.Successor;
}
else
{
// delete node
TextAnchorNode s = node.Successor;
remainingRemovalLength -= node.length;
RemoveNode(node);
// we already deleted the node, don't delete it twice
nodesToDelete.Remove(node);
if (anchor != null)
{
anchor.OnDeleted(delayedEvents);
}
node = s;
}
}
// 'node' now is the first anchor after the deleted segment.
// If there are no anchors after the deleted segment, 'node' is null.
// firstDeletionSurvivor was set to the first node surviving deletion.
// Because all non-surviving nodes up to 'node' were deleted, the node range
// [firstDeletionSurvivor, node) now refers to the set of all deletion survivors.
// do the remaining job of the removal
if (node != null)
{
node.length -= remainingRemovalLength;
Debug.Assert(node.length >= 0);
}
if (entry.InsertionLength > 0)
{
// we are performing a replacement
if (firstDeletionSurvivor != null)
{
// We got deletion survivors which need to be split into BeforeInsertion
// and AfterInsertion groups.
// Take care that we don't regroup everything at offset, but only the deletion
// survivors - from firstDeletionSurvivor (inclusive) to node (exclusive).
// This ensures that nodes immediately before or after the replaced segment
// stay where they are (independent from their MovementType)
PerformInsertText(firstDeletionSurvivor, node, entry.InsertionLength, entry.DefaultAnchorMovementIsBeforeInsertion);
}
else if (node != null)
{
// No deletion survivors:
// just perform the insertion
node.length += entry.InsertionLength;
}
}
if (node != null)
{
UpdateAugmentedData(node);
}
DeleteMarkedNodes();
}
/// <summary>
/// Replaces text.
/// </summary>
/// <param name="offset">The starting offset of the text to be replaced.</param>
/// <param name="length">The length of the text to be replaced.</param>
/// <param name="text">The new text.</param>
/// <param name="offsetChangeMappingType">The offsetChangeMappingType determines how offsets inside the old text are mapped to the new text.
/// This affects how the anchors and segments inside the replaced region behave.</param>
public void Replace(int offset, int length, ITextSource text, OffsetChangeMappingType offsetChangeMappingType)
{
if (text == null)
{
throw new ArgumentNullException("text");
}
// Please see OffsetChangeMappingType XML comments for details on how these modes work.
switch (offsetChangeMappingType)
{
case OffsetChangeMappingType.Normal:
Replace(offset, length, text, null);
break;
case OffsetChangeMappingType.KeepAnchorBeforeInsertion:
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(
new OffsetChangeMapEntry(offset, length, text.TextLength, false, true)));
break;
case OffsetChangeMappingType.RemoveAndInsert:
if (length == 0 || text.TextLength == 0)
{
// only insertion or only removal?
// OffsetChangeMappingType doesn't matter, just use Normal.
Replace(offset, length, text, null);
}
else
{
OffsetChangeMap map = new OffsetChangeMap(2);
map.Add(new OffsetChangeMapEntry(offset, length, 0));
map.Add(new OffsetChangeMapEntry(offset, 0, text.TextLength));
map.Freeze();
Replace(offset, length, text, map);
}
break;
case OffsetChangeMappingType.CharacterReplace:
if (length == 0 || text.TextLength == 0)
{
// only insertion or only removal?
// OffsetChangeMappingType doesn't matter, just use Normal.
Replace(offset, length, text, null);
}
else if (text.TextLength > length)
{
// look at OffsetChangeMappingType.CharacterReplace XML comments on why we need to replace
// the last character
OffsetChangeMapEntry entry = new OffsetChangeMapEntry(offset + length - 1, 1, 1 + text.TextLength - length);
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(entry));
}
else if (text.TextLength < length)
{
OffsetChangeMapEntry entry = new OffsetChangeMapEntry(offset + text.TextLength, length - text.TextLength, 0, true, false);
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(entry));
}
else
{
Replace(offset, length, text, OffsetChangeMap.Empty);
}
break;
default:
throw new ArgumentOutOfRangeException("offsetChangeMappingType", offsetChangeMappingType, "Invalid enum value");
}
}
