/// <summary>
/// Replaces the text in a line.
/// If only whitespace at the beginning and end of the line was changed, this method
/// only adjusts the whitespace and doesn't replace the other text.
/// </summary>
public static void SmartReplaceLine(Document document, LineSegment line, string newLineText)
{
if (document == null)
{
throw new ArgumentNullException("document");
}
if (line == null)
{
throw new ArgumentNullException("line");
}
if (newLineText == null)
{
throw new ArgumentNullException("newLineText");
}
string newLineTextTrim = newLineText.Trim(WS_CHARS);
string oldLineText = document.GetText(line);
if (oldLineText == newLineText)
{
return;
}
int pos = oldLineText.IndexOf(newLineTextTrim);
if (newLineTextTrim.Length > 0 && pos >= 0)
{
document.UndoStack.StartUndoGroup();
try
{
// find whitespace at beginning
int startWhitespaceLength = 0;
while (startWhitespaceLength < newLineText.Length)
{
char c = newLineText[startWhitespaceLength];
if (c != ' ' && c != '\t')
{
break;
}
startWhitespaceLength++;
}
// find whitespace at end
int endWhitespaceLength = newLineText.Length - newLineTextTrim.Length - startWhitespaceLength;
// replace whitespace sections
int lineOffset = line.Offset;
document.Replace(lineOffset + pos + newLineTextTrim.Length, line.Length - pos - newLineTextTrim.Length, newLineText.Substring(newLineText.Length - endWhitespaceLength));
document.Replace(lineOffset, pos, newLineText.Substring(0, startWhitespaceLength));
}
finally
{
document.UndoStack.EndUndoGroup();
}
}
else
{
document.Replace(line.Offset, line.Length, newLineText);
}
}