C++ SourceColumnMap::columns方法代码示例

/// \brief When the source code line we want to print is too long for
/// the terminal, select the "interesting" region.
static void selectInterestingSourceRegion(std::string &SourceLine,
                                          std::string &CaretLine,
                                          std::string &FixItInsertionLine,
                                          unsigned Columns,
                                          const SourceColumnMap &map) {
  unsigned MaxColumns = std::max<unsigned>(map.columns(),
                                           std::max(CaretLine.size(),
                                                    FixItInsertionLine.size()));
  // if the number of columns is less than the desired number we're done
  if (MaxColumns <= Columns)
    return;

  // no special characters allowed in CaretLine or FixItInsertionLine
  assert(CaretLine.end() ==
         std::find_if(CaretLine.begin(), CaretLine.end(),
         char_out_of_range(' ','~')));
  assert(FixItInsertionLine.end() ==
         std::find_if(FixItInsertionLine.begin(), FixItInsertionLine.end(),
         char_out_of_range(' ','~')));

  // Find the slice that we need to display the full caret line
  // correctly.
  unsigned CaretStart = 0, CaretEnd = CaretLine.size();
  for (; CaretStart != CaretEnd; ++CaretStart)
    if (!isspace(static_cast<unsigned char>(CaretLine[CaretStart])))
      break;

  for (; CaretEnd != CaretStart; --CaretEnd)
    if (!isspace(static_cast<unsigned char>(CaretLine[CaretEnd - 1])))
      break;

  // caret has already been inserted into CaretLine so the above whitespace
  // check is guaranteed to include the caret

  // If we have a fix-it line, make sure the slice includes all of the
  // fix-it information.
  if (!FixItInsertionLine.empty()) {
    unsigned FixItStart = 0, FixItEnd = FixItInsertionLine.size();
    for (; FixItStart != FixItEnd; ++FixItStart)
      if (!isspace(static_cast<unsigned char>(FixItInsertionLine[FixItStart])))
        break;

    for (; FixItEnd != FixItStart; --FixItEnd)
      if (!isspace(static_cast<unsigned char>(FixItInsertionLine[FixItEnd - 1])))
        break;

    CaretStart = std::min(FixItStart, CaretStart);
    CaretEnd = std::max(FixItEnd, CaretEnd);
  }

  // CaretEnd may have been set at the middle of a character
  // If it's not at a character's first column then advance it past the current
  //   character.
  while (static_cast<int>(CaretEnd) < map.columns() &&
         -1 == map.columnToByte(CaretEnd))
    ++CaretEnd;

  assert((static_cast<int>(CaretStart) > map.columns() ||
          -1!=map.columnToByte(CaretStart)) &&
         "CaretStart must not point to a column in the middle of a source"
         " line character");
  assert((static_cast<int>(CaretEnd) > map.columns() ||
          -1!=map.columnToByte(CaretEnd)) &&
         "CaretEnd must not point to a column in the middle of a source line"
         " character");

  // CaretLine[CaretStart, CaretEnd) contains all of the interesting
  // parts of the caret line. While this slice is smaller than the
  // number of columns we have, try to grow the slice to encompass
  // more context.

  unsigned SourceStart = map.columnToByte(std::min<unsigned>(CaretStart,
                                                             map.columns()));
  unsigned SourceEnd = map.columnToByte(std::min<unsigned>(CaretEnd,
                                                           map.columns()));

  unsigned CaretColumnsOutsideSource = CaretEnd-CaretStart
    - (map.byteToColumn(SourceEnd)-map.byteToColumn(SourceStart));

  char const *front_ellipse = "  ...";
  char const *front_space   = "     ";
  char const *back_ellipse = "...";
  unsigned ellipses_space = strlen(front_ellipse) + strlen(back_ellipse);

  unsigned TargetColumns = Columns;
  // Give us extra room for the ellipses
  //  and any of the caret line that extends past the source
  if (TargetColumns > ellipses_space+CaretColumnsOutsideSource)
    TargetColumns -= ellipses_space+CaretColumnsOutsideSource;

  while (SourceStart>0 || SourceEnd<SourceLine.size()) {
    bool ExpandedRegion = false;

    if (SourceStart>0) {
      unsigned NewStart = map.startOfPreviousColumn(SourceStart);

      // Skip over any whitespace we see here; we're looking for
      // another bit of interesting text.
//.........这里部分代码省略.........

/// \brief Emit a code snippet and caret line.
///
/// This routine emits a single line's code snippet and caret line..
///
/// \param Loc The location for the caret.
/// \param Ranges The underlined ranges for this code snippet.
/// \param Hints The FixIt hints active for this diagnostic.
void TextDiagnostic::emitSnippetAndCaret(
    SourceLocation Loc, DiagnosticsEngine::Level Level,
    SmallVectorImpl<CharSourceRange>& Ranges,
    ArrayRef<FixItHint> Hints,
    const SourceManager &SM) {
  assert(Loc.isValid() && "must have a valid source location here");
  assert(Loc.isFileID() && "must have a file location here");

  // If caret diagnostics are enabled and we have location, we want to
  // emit the caret.  However, we only do this if the location moved
  // from the last diagnostic, if the last diagnostic was a note that
  // was part of a different warning or error diagnostic, or if the
  // diagnostic has ranges.  We don't want to emit the same caret
  // multiple times if one loc has multiple diagnostics.
  if (!DiagOpts->ShowCarets)
    return;
  if (Loc == LastLoc && Ranges.empty() && Hints.empty() &&
      (LastLevel != DiagnosticsEngine::Note || Level == LastLevel))
    return;

  // Decompose the location into a FID/Offset pair.
  std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(Loc);
  FileID FID = LocInfo.first;
  unsigned FileOffset = LocInfo.second;

  // Get information about the buffer it points into.
  bool Invalid = false;
  StringRef BufData = SM.getBufferData(FID, &Invalid);
  if (Invalid)
    return;

  const char *BufStart = BufData.data();
  const char *BufEnd = BufStart + BufData.size();

  unsigned LineNo = SM.getLineNumber(FID, FileOffset);
  unsigned ColNo = SM.getColumnNumber(FID, FileOffset);
  
  // Arbitrarily stop showing snippets when the line is too long.
  static const size_t MaxLineLengthToPrint = 4096;
  if (ColNo > MaxLineLengthToPrint)
    return;

  // Rewind from the current position to the start of the line.
  const char *TokPtr = BufStart+FileOffset;
  const char *LineStart = TokPtr-ColNo+1; // Column # is 1-based.

  // Compute the line end.  Scan forward from the error position to the end of
  // the line.
  const char *LineEnd = TokPtr;
  while (*LineEnd != '\n' && *LineEnd != '\r' && LineEnd != BufEnd)
    ++LineEnd;

  // Arbitrarily stop showing snippets when the line is too long.
  if (size_t(LineEnd - LineStart) > MaxLineLengthToPrint)
    return;

  // Trim trailing null-bytes.
  StringRef Line(LineStart, LineEnd - LineStart);
  while (Line.size() > ColNo && Line.back() == '\0')
    Line = Line.drop_back();

  // Copy the line of code into an std::string for ease of manipulation.
  std::string SourceLine(Line.begin(), Line.end());

  // Build the byte to column map.
  const SourceColumnMap sourceColMap(SourceLine, DiagOpts->TabStop);

  // Create a line for the caret that is filled with spaces that is the same
  // number of columns as the line of source code.
  std::string CaretLine(sourceColMap.columns(), ' ');

  // Highlight all of the characters covered by Ranges with ~ characters.
  for (SmallVectorImpl<CharSourceRange>::iterator I = Ranges.begin(),
                                                  E = Ranges.end();
       I != E; ++I)
    highlightRange(*I, LineNo, FID, sourceColMap, CaretLine, SM, LangOpts);

  // Next, insert the caret itself.
  ColNo = sourceColMap.byteToContainingColumn(ColNo-1);
  if (CaretLine.size()<ColNo+1)
    CaretLine.resize(ColNo+1, ' ');
  CaretLine[ColNo] = '^';

  std::string FixItInsertionLine = buildFixItInsertionLine(LineNo,
                                                           sourceColMap,
                                                           Hints, SM,
                                                           DiagOpts.get());

  // If the source line is too long for our terminal, select only the
  // "interesting" source region within that line.
  unsigned Columns = DiagOpts->MessageLength;
  if (Columns)
    selectInterestingSourceRegion(SourceLine, CaretLine, FixItInsertionLine,
//.........这里部分代码省略.........