/// <summary>
/// Gets a source fragment
/// </summary>
/// <param name="sourceCode">Source code</param>
/// <param name="nodeCoordinates">Node coordinates</param>
/// <param name="tabSize">Number of spaces in the tab</param>
/// <param name="maxFragmentLength">Maximum length of the source fragment</param>
/// <returns>Source fragment</returns>
internal static string GetSourceFragment(string sourceCode,
SourceCodeNodeCoordinates nodeCoordinates, byte tabSize = DEFAULT_TAB_SIZE,
int maxFragmentLength = DEFAULT_MAX_FRAGMENT_LENGTH)
{
string sourceFragment = string.Empty;
int lineNumber = nodeCoordinates.LineNumber;
int columnNumber = nodeCoordinates.ColumnNumber;
if (!string.IsNullOrEmpty(sourceCode))
{
int previousLineNumber = lineNumber - 1;
int currentLineNumber = lineNumber;
int nextLineNumber = lineNumber + 1;
string previousLine = string.Empty;
string currentLine = string.Empty;
string nextLine = string.Empty;
int lineCount = 0;
int lineBreakPosition = int.MinValue;
int lineBreakLength = 0;
do
{
string line;
int startLinePosition = lineBreakPosition == int.MinValue ? 0 : lineBreakPosition + lineBreakLength;
FindNextLineBreak(sourceCode, startLinePosition, out lineBreakPosition, out lineBreakLength);
if (lineBreakPosition != -1)
{
line = sourceCode.Substring(startLinePosition, lineBreakPosition - startLinePosition);
}
else
{
line = sourceCode.Substring(startLinePosition);
}
lineCount++;
if (lineCount == previousLineNumber)
{
previousLine = line;
}
else if (lineCount == currentLineNumber)
{
currentLine = line;
}
else if (lineCount == nextLineNumber)
{
nextLine = line;
}
}while (lineBreakPosition != -1 && lineCount <= nextLineNumber);
int lineNumberSize = nextLineNumber.ToString(CultureInfo.InvariantCulture).Length;
if (currentLineNumber == lineCount)
{
lineNumberSize = currentLineNumber.ToString(CultureInfo.InvariantCulture).Length;
}
int fragmentStartPosition;
int fragmentLength;
CalculateCutPositions(currentLine, columnNumber, maxFragmentLength,
out fragmentStartPosition, out fragmentLength);
var stringBuilderPool = StringBuilderPool.Shared;
StringBuilder sourceFragmentBuilder = stringBuilderPool.Rent();
if (currentLine.Length > 0)
{
if (previousLine.Length > 0)
{
sourceFragmentBuilder.AppendLine(FormatSourceCodeLine(previousLine,
new SourceCodeNodeCoordinates(previousLineNumber, 0),
lineNumberSize, fragmentStartPosition, fragmentLength, tabSize));
}
sourceFragmentBuilder.AppendLine(FormatSourceCodeLine(currentLine,
new SourceCodeNodeCoordinates(currentLineNumber, columnNumber),
lineNumberSize, fragmentStartPosition, fragmentLength, tabSize));
if (nextLine.Length > 0)
{
sourceFragmentBuilder.AppendLine(FormatSourceCodeLine(nextLine,
new SourceCodeNodeCoordinates(nextLineNumber, 0),
lineNumberSize, fragmentStartPosition, fragmentLength, tabSize));
}
sourceFragmentBuilder.TrimEnd();
}
sourceFragment = sourceFragmentBuilder.ToString();
stringBuilderPool.Return(sourceFragmentBuilder);
}
return(sourceFragment);
}
/// <summary>
/// Formats a line of source code
/// </summary>
/// <param name="line">Line content</param>
/// <param name="nodeCoordinates">Node coordinates</param>
/// <param name="lineNumberSize">Number of symbols in the line number caption</param>
/// <param name="fragmentStartPosition">Start position of source fragment</param>
/// <param name="fragmentLength">Length of source fragment</param>
/// <param name="tabSize">Number of spaces in the tab</param>
/// <returns>Formatted line</returns>
private static string FormatSourceCodeLine(string line, SourceCodeNodeCoordinates nodeCoordinates,
int lineNumberSize, int fragmentStartPosition = 0, int fragmentLength = 0, byte tabSize = 4)
{
const string ellipsisSymbol = "…";
const byte leftPaddingSize = 7;
int lineNumber = nodeCoordinates.LineNumber;
int columnNumber = nodeCoordinates.ColumnNumber;
int lineLength = line.Length;
string processedLine;
if (fragmentStartPosition == 0 && fragmentLength == lineLength)
{
processedLine = line;
}
else if (fragmentStartPosition >= lineLength)
{
processedLine = string.Empty;
}
else
{
int fragmentEndPosition = fragmentStartPosition + fragmentLength - 1;
bool beginningCutOff = fragmentStartPosition > 0;
bool endingCutOff = fragmentEndPosition <= lineLength;
if (fragmentEndPosition + 1 == lineLength)
{
endingCutOff = false;
}
if (fragmentEndPosition >= lineLength)
{
endingCutOff = false;
fragmentEndPosition = lineLength - 1;
fragmentLength = fragmentEndPosition - fragmentStartPosition + 1;
}
processedLine = line.Substring(fragmentStartPosition, fragmentLength);
if (beginningCutOff)
{
processedLine = ellipsisSymbol + processedLine;
}
if (endingCutOff)
{
processedLine = processedLine + ellipsisSymbol;
}
}
string result = string.Format("Line {0}: {1}",
lineNumber.ToString(CultureInfo.InvariantCulture).PadLeft(lineNumberSize),
processedLine.TabsToSpaces(tabSize));
if (columnNumber > 0)
{
int cursorOffset = columnNumber - fragmentStartPosition;
if (fragmentStartPosition > 0)
{
cursorOffset++;
}
result += Environment.NewLine + string.Empty
.PadRight(
(cursorOffset < processedLine.Length ?
processedLine.Substring(0, cursorOffset - 1) : processedLine
).TabsToSpaces(tabSize).Length + lineNumberSize + leftPaddingSize
)
.Replace(" ", "-") + "^"
;
}
return(result);
}