/// <summary>
/// Find if the current insertion point is a comment and, if it is, insert a * on the following
/// line at the correct indentation.
/// </summary>
public static void FormatMultilineComment(this ITextView textView, SnapshotPoint commentStartingPoint, SnapshotPoint insertionPoint)
{
// Since this was marked as a comment span (before calling this method), this method does not
// handle being called from insertion points not in/following a multiline comment.
bool commentStartingPointPrechecks =
commentStartingPoint.Snapshot != null &&
commentStartingPoint.Position + 2 <= commentStartingPoint.Snapshot.Length &&
commentStartingPoint.Snapshot.GetText(commentStartingPoint.Position, 2) == "/*";
bool insertionPointPrechecks =
insertionPoint.Snapshot != null &&
insertionPoint.Position > commentStartingPoint.Position;
var snapshot = commentStartingPoint.Snapshot;
Debug.Assert(commentStartingPointPrechecks,
"Comment Starting Point should be set to the beginning of a multiline comment.");
Debug.Assert(insertionPointPrechecks,
"Insertion Point must be set to a position after the Comment Starting Point");
// If for any reason any of the prechecks fail, just don't format the comment. A no-op seems better than
// an odd formatting result...
if (!commentStartingPointPrechecks || !insertionPointPrechecks)
{
return;
}
// Figure out the amount of whitespace preceeding the * on the line. Take spacing style with this to match.
int startOfFirstCommentLine = snapshot.GetLineFromPosition(commentStartingPoint).Start;
string beforeAsterisk = snapshot.GetText(startOfFirstCommentLine, commentStartingPoint - startOfFirstCommentLine);
// If ConvertTabsToSpaces is enabled, do that and make a string of all spaces of the same length.
// Otherwise, walk the string and replace all non-whitespace characters with a space and use that string.
if (textView.Options.IsConvertTabsToSpacesEnabled())
{
var tabSize = textView.Options.GetTabSize();
beforeAsterisk = String.Format("{0} *", TextHelper.ConvertTabsToSpaces(beforeAsterisk, tabSize, true));
}
else
{
// Create a string builder and make it 2 spaces bigger for the asterisk at the end.
var sb = new StringBuilder(beforeAsterisk.Length + 2);
// If the user wants to keep tabs, then we need to keep them in here. Convert non-whitespace characters.
for (int i = 0; i < beforeAsterisk.Length; i++)
{
if (!char.IsWhiteSpace(beforeAsterisk[i]))
{
sb.Append(" ");
}
else
{
sb.Append(beforeAsterisk[i]);
}
}
sb.Append(" *");
beforeAsterisk = sb.ToString();
}
// Calculate the amount of space following the *. 1 if there is only whitespace, indent otherwise.
string afterAsterisk = " "; // by default we want a single space
if (insertionPoint.Position >= 1) // only do if we aren't the first line.
{
string previousLineText = snapshot.GetLineFromPosition(insertionPoint.Position - 1).GetText();
// Replace tabs in previous line string if we have that option set so later calculations are correct.
if (textView.Options.IsConvertTabsToSpacesEnabled())
{
var tabSize = textView.Options.GetTabSize();
previousLineText = TextHelper.ConvertTabsToSpaces(previousLineText, tabSize);
}
string trimmedPreviousLine = previousLineText.Trim();
if (trimmedPreviousLine.StartsWith("*") && trimmedPreviousLine.Length != 1)
{
// if it started with the *, take the whitespace between that and the next non-whitespace character.
// trim the whitespace off the front so we know how much of the string was whitespace after the asterisk
var whitespaceStringLength = trimmedPreviousLine.Length - trimmedPreviousLine.Substring(1).TrimStart().Length - 1;
afterAsterisk = trimmedPreviousLine.Substring(1, whitespaceStringLength);
}
}
// Find the position to insert the new line.
int commentInsertionPoint = insertionPoint;
// Insert the whitespace * string and set the caret to the correct position
using (var edit = snapshot.TextBuffer.CreateEdit()) {
edit.Insert(commentInsertionPoint, beforeAsterisk + afterAsterisk);
edit.Apply();
}
var pt = textView.BufferGraph.MapUpToBuffer(
new SnapshotPoint(snapshot.TextBuffer.CurrentSnapshot, commentInsertionPoint + beforeAsterisk.Length + afterAsterisk.Length),
PointTrackingMode.Positive,
PositionAffinity.Successor,
textView.TextSnapshot.TextBuffer
);
if (pt != null)
{
// Set the cursor position immediatelly following our edit to guarantee placement.
textView.Caret.MoveTo(pt.Value);
}
}
