private void doReplaceString(int startOffset, int endOffset, CharSequence s) {
    assert intersectWithEditable(new TextRange(startOffset, startOffset)) != null;
    assert intersectWithEditable(new TextRange(endOffset, endOffset)) != null;

    List<Pair<TextRange, CharSequence>> hostRangesToModify;
    synchronized (myLock) {
      hostRangesToModify = new ArrayList<Pair<TextRange, CharSequence>>(myShreds.size());

      int offset = startOffset;
      int curRangeStart = 0;
      for (int i = 0; i < myShreds.size(); i++) {
        PsiLanguageInjectionHost.Shred shred = myShreds.get(i);
        curRangeStart += shred.getPrefix().length();
        if (offset < curRangeStart) offset = curRangeStart;
        Segment hostRange = shred.getHostRangeMarker();
        if (hostRange == null) continue;
        int hostRangeLength = hostRange.getEndOffset() - hostRange.getStartOffset();
        TextRange range = TextRange.from(curRangeStart, hostRangeLength);
        if (range.contains(offset)
            || range.getEndOffset() == offset /* in case of inserting at the end*/) {
          TextRange rangeToModify =
              new TextRange(offset, Math.min(range.getEndOffset(), endOffset));
          TextRange hostRangeToModify =
              rangeToModify.shiftRight(hostRange.getStartOffset() - curRangeStart);
          CharSequence toReplace =
              i == myShreds.size() - 1
                      || range.getEndOffset() + shred.getSuffix().length() >= endOffset
                  ? s
                  : s.subSequence(0, Math.min(hostRangeToModify.getLength(), s.length()));
          s = toReplace == s ? "" : s.subSequence(toReplace.length(), s.length());
          hostRangesToModify.add(Pair.create(hostRangeToModify, toReplace));
          offset = rangeToModify.getEndOffset();
        }
        curRangeStart += hostRangeLength;
        curRangeStart += shred.getSuffix().length();
        if (curRangeStart > endOffset) break;
      }
    }

    int delta = 0;
    for (Pair<TextRange, CharSequence> pair : hostRangesToModify) {
      TextRange hostRange = pair.getFirst();
      CharSequence replace = pair.getSecond();

      myDelegate.replaceString(
          hostRange.getStartOffset() + delta, hostRange.getEndOffset() + delta, replace);
      delta -= hostRange.getLength() - replace.length();
    }
  }
  private static void highlightTodos(
      @NotNull PsiFile file,
      @NotNull CharSequence text,
      int startOffset,
      int endOffset,
      @NotNull ProgressIndicator progress,
      @NotNull ProperTextRange priorityRange,
      @NotNull Collection<HighlightInfo> result,
      @NotNull Collection<HighlightInfo> outsideResult) {
    PsiSearchHelper helper = PsiSearchHelper.SERVICE.getInstance(file.getProject());
    TodoItem[] todoItems = helper.findTodoItems(file, startOffset, endOffset);
    if (todoItems.length == 0) return;

    for (TodoItem todoItem : todoItems) {
      progress.checkCanceled();
      TextRange range = todoItem.getTextRange();
      String description =
          text.subSequence(range.getStartOffset(), range.getEndOffset()).toString();
      TextAttributes attributes = todoItem.getPattern().getAttributes().getTextAttributes();
      HighlightInfo info =
          HighlightInfo.createHighlightInfo(
              HighlightInfoType.TODO, range, description, description, attributes);
      assert info != null;
      if (priorityRange.containsRange(info.getStartOffset(), info.getEndOffset())) {
        result.add(info);
      } else {
        outsideResult.add(info);
      }
    }
  }
 private static int getNewIndent(final PsiFile psiFile, final int firstWhitespace) {
   final Document document = psiFile.getViewProvider().getDocument();
   final int startOffset = document.getLineStartOffset(document.getLineNumber(firstWhitespace));
   int endOffset = startOffset;
   final CharSequence charsSequence = document.getCharsSequence();
   while (Character.isWhitespace(charsSequence.charAt(endOffset++))) ;
   final String newIndentStr = charsSequence.subSequence(startOffset, endOffset - 1).toString();
   return IndentHelperImpl.getIndent(
       psiFile.getProject(), psiFile.getFileType(), newIndentStr, true);
 }
  @Override
  public void replaceString(int startOffset, int endOffset, @NotNull CharSequence s) {
    if (isOneLine()) {
      s = StringUtil.replace(s.toString(), "\n", "");
    }

    final CharSequence chars = getCharsSequence();
    CharSequence toDelete = chars.subSequence(startOffset, endOffset);

    int perfixLength = StringUtil.commonPrefixLength(s, toDelete);
    int suffixLength =
        StringUtil.commonSuffixLength(
            toDelete.subSequence(perfixLength, toDelete.length()),
            s.subSequence(perfixLength, s.length()));
    startOffset += perfixLength;
    endOffset -= suffixLength;
    s = s.subSequence(perfixLength, s.length() - suffixLength);

    doReplaceString(startOffset, endOffset, s);
  }
 private static void adjustIndentationInRange(
     final PsiFile file,
     final Document document,
     final TextRange[] indents,
     final int indentAdjustment) {
   final CharSequence charsSequence = document.getCharsSequence();
   for (final TextRange indent : indents) {
     final String oldIndentStr =
         charsSequence.subSequence(indent.getStartOffset() + 1, indent.getEndOffset()).toString();
     final int oldIndent =
         IndentHelperImpl.getIndent(file.getProject(), file.getFileType(), oldIndentStr, true);
     final String newIndentStr =
         IndentHelperImpl.fillIndent(
             file.getProject(), file.getFileType(), Math.max(oldIndent + indentAdjustment, 0));
     document.replaceString(indent.getStartOffset() + 1, indent.getEndOffset(), newIndentStr);
   }
 }
  @Override
  public int getLineNumber(int offset) {
    int lineNumber = 0;
    String hostText = myDelegate.getText();
    synchronized (myLock) {
      for (PsiLanguageInjectionHost.Shred shred : myShreds) {
        String prefix = shred.getPrefix();
        String suffix = shred.getSuffix();
        lineNumber +=
            StringUtil.getLineBreakCount(prefix.substring(0, Math.min(offset, prefix.length())));
        if (offset < prefix.length()) {
          return lineNumber;
        }
        offset -= prefix.length();

        Segment currentRange = shred.getHostRangeMarker();
        if (currentRange == null) continue;
        int rangeLength = currentRange.getEndOffset() - currentRange.getStartOffset();
        CharSequence rangeText =
            hostText.subSequence(currentRange.getStartOffset(), currentRange.getEndOffset());

        lineNumber +=
            StringUtil.getLineBreakCount(rangeText.subSequence(0, Math.min(offset, rangeLength)));
        if (offset < rangeLength) {
          return lineNumber;
        }
        offset -= rangeLength;

        lineNumber +=
            StringUtil.getLineBreakCount(suffix.substring(0, Math.min(offset, suffix.length())));
        if (offset < suffix.length()) {
          return lineNumber;
        }

        offset -= suffix.length();
      }
    }
    lineNumber = getLineCount() - 1;
    return lineNumber < 0 ? 0 : lineNumber;
  }