C++ SourceColumnMap::startOfNextColumn方法代码示例

/// \brief Highlight a SourceRange (with ~'s) for any characters on LineNo.
static void highlightRange(const CharSourceRange &R,
                           unsigned LineNo, FileID FID,
                           const SourceColumnMap &map,
                           std::string &CaretLine,
                           const SourceManager &SM,
                           const LangOptions &LangOpts) {
  if (!R.isValid()) return;

  SourceLocation Begin = R.getBegin();
  SourceLocation End = R.getEnd();

  unsigned StartLineNo = SM.getExpansionLineNumber(Begin);
  if (StartLineNo > LineNo || SM.getFileID(Begin) != FID)
    return;  // No intersection.

  unsigned EndLineNo = SM.getExpansionLineNumber(End);
  if (EndLineNo < LineNo || SM.getFileID(End) != FID)
    return;  // No intersection.

  // Compute the column number of the start.
  unsigned StartColNo = 0;
  if (StartLineNo == LineNo) {
    StartColNo = SM.getExpansionColumnNumber(Begin);
    if (StartColNo) --StartColNo;  // Zero base the col #.
  }

  // Compute the column number of the end.
  unsigned EndColNo = map.getSourceLine().size();
  if (EndLineNo == LineNo) {
    EndColNo = SM.getExpansionColumnNumber(End);
    if (EndColNo) {
      --EndColNo;  // Zero base the col #.

      // Add in the length of the token, so that we cover multi-char tokens if
      // this is a token range.
      if (R.isTokenRange())
        EndColNo += Lexer::MeasureTokenLength(End, SM, LangOpts);
    } else {
      EndColNo = CaretLine.size();
    }
  }

  assert(StartColNo <= EndColNo && "Invalid range!");

  // Check that a token range does not highlight only whitespace.
  if (R.isTokenRange()) {
    // Pick the first non-whitespace column.
    while (StartColNo < map.getSourceLine().size() &&
           (map.getSourceLine()[StartColNo] == ' ' ||
            map.getSourceLine()[StartColNo] == '\t'))
      StartColNo = map.startOfNextColumn(StartColNo);

    // Pick the last non-whitespace column.
    if (EndColNo > map.getSourceLine().size())
      EndColNo = map.getSourceLine().size();
    while (EndColNo-1 &&
           (map.getSourceLine()[EndColNo-1] == ' ' ||
            map.getSourceLine()[EndColNo-1] == '\t'))
      EndColNo = map.startOfPreviousColumn(EndColNo);

    // If the start/end passed each other, then we are trying to highlight a
    // range that just exists in whitespace, which must be some sort of other
    // bug.
    assert(StartColNo <= EndColNo && "Trying to highlight whitespace??");
  }

  assert(StartColNo <= map.getSourceLine().size() && "Invalid range!");
  assert(EndColNo <= map.getSourceLine().size() && "Invalid range!");

  // Fill the range with ~'s.
  StartColNo = map.byteToContainingColumn(StartColNo);
  EndColNo = map.byteToContainingColumn(EndColNo);

  assert(StartColNo <= EndColNo && "Invalid range!");
  if (CaretLine.size() < EndColNo)
    CaretLine.resize(EndColNo,' ');
  std::fill(CaretLine.begin()+StartColNo,CaretLine.begin()+EndColNo,'~');
}

//.........这里部分代码省略.........
  // 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.
      // FIXME: Detect non-ASCII whitespace characters too.
      while (NewStart &&
             isspace(static_cast<unsigned char>(SourceLine[NewStart])))
        NewStart = map.startOfPreviousColumn(NewStart);

      // Skip over this bit of "interesting" text.
      while (NewStart) {
        unsigned Prev = map.startOfPreviousColumn(NewStart);
        if (isspace(static_cast<unsigned char>(SourceLine[Prev])))
          break;
        NewStart = Prev;
      }

      assert(map.byteToColumn(NewStart) != -1);
      unsigned NewColumns = map.byteToColumn(SourceEnd) -
                              map.byteToColumn(NewStart);
      if (NewColumns <= TargetColumns) {
        SourceStart = NewStart;
        ExpandedRegion = true;
      }
    }

    if (SourceEnd<SourceLine.size()) {
      unsigned NewEnd = map.startOfNextColumn(SourceEnd);

      // Skip over any whitespace we see here; we're looking for
      // another bit of interesting text.
      // FIXME: Detect non-ASCII whitespace characters too.
      while (NewEnd < SourceLine.size() &&
             isspace(static_cast<unsigned char>(SourceLine[NewEnd])))
        NewEnd = map.startOfNextColumn(NewEnd);

      // Skip over this bit of "interesting" text.
      while (NewEnd < SourceLine.size() &&
             !isspace(static_cast<unsigned char>(SourceLine[NewEnd])))
        NewEnd = map.startOfNextColumn(NewEnd);

      assert(map.byteToColumn(NewEnd) != -1);
      unsigned NewColumns = map.byteToColumn(NewEnd) -
                              map.byteToColumn(SourceStart);
      if (NewColumns <= TargetColumns) {
        SourceEnd = NewEnd;
        ExpandedRegion = true;
      }
    }

    if (!ExpandedRegion)
      break;
  }

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

  // [CaretStart, CaretEnd) is the slice we want. Update the various
  // output lines to show only this slice, with two-space padding
  // before the lines so that it looks nicer.

  assert(CaretStart!=(unsigned)-1 && CaretEnd!=(unsigned)-1 &&
         SourceStart!=(unsigned)-1 && SourceEnd!=(unsigned)-1);
  assert(SourceStart <= SourceEnd);
  assert(CaretStart <= CaretEnd);

  unsigned BackColumnsRemoved
    = map.byteToColumn(SourceLine.size())-map.byteToColumn(SourceEnd);
  unsigned FrontColumnsRemoved = CaretStart;
  unsigned ColumnsKept = CaretEnd-CaretStart;

  // We checked up front that the line needed truncation
  assert(FrontColumnsRemoved+ColumnsKept+BackColumnsRemoved > Columns);

  // The line needs some trunctiona, and we'd prefer to keep the front
  //  if possible, so remove the back
  if (BackColumnsRemoved > strlen(back_ellipse))
    SourceLine.replace(SourceEnd, std::string::npos, back_ellipse);

  // If that's enough then we're done
  if (FrontColumnsRemoved+ColumnsKept <= Columns)
    return;

  // Otherwise remove the front as well
  if (FrontColumnsRemoved > strlen(front_ellipse)) {
    SourceLine.replace(0, SourceStart, front_ellipse);
    CaretLine.replace(0, CaretStart, front_space);
    if (!FixItInsertionLine.empty())
      FixItInsertionLine.replace(0, CaretStart, front_space);
  }
}