/// CheckLists - Compare expected to seen diagnostic lists and return the
/// the difference between them.
///
static unsigned CheckLists(DiagnosticsEngine &Diags, const llvm::SourceMgr &SourceMgr,
                           DiagnosticsEngine::Level Label,
                           DirectiveList &Left,
                           const_diag_iterator d2_begin,
                           const_diag_iterator d2_end) {
  DirectiveList LeftOnly;
  DiagList Right(d2_begin, d2_end);

  for (DirectiveList::iterator I = Left.begin(), E = Left.end(); I != E; ++I) {
    Directive& D = **I;
    unsigned LineNo1 = SourceMgr.FindLineNumber(D.DiagnosticLoc);

    for (unsigned i = 0; i < D.Max; ++i) {
      DiagList::iterator II, IE;
      for (II = Right.begin(), IE = Right.end(); II != IE; ++II) {
        unsigned LineNo2 = SourceMgr.FindLineNumber(II->first);
        if (LineNo1 != LineNo2)
          continue;

        if (!IsFromSameFile(SourceMgr, D.DiagnosticLoc, II->first))
          continue;

        const std::string &RightText = II->second;
        if (D.match(RightText))
          break;
      }
      if (II == IE) {
        // Not found.
        if (i >= D.Min) break;
        LeftOnly.push_back(*I);
      } else {
        // Found. The same cannot be found twice.
        Right.erase(II);
      }
    }
  }
  // Now all that's left in Right are those that were not matched.
  unsigned num = PrintExpected(Diags, SourceMgr, LeftOnly, Label);
  num += PrintUnexpected(Diags, &SourceMgr, Right.begin(), Right.end(), Label);
  return num;
}
/// ParseDirective - Go through the comment and see if it indicates expected
/// diagnostics. If so, then put them in the appropriate directive list.
///
/// Returns true if any valid directives were found.
static bool ParseDirective(StringRef S, ExpectedData *ED, const llvm::SourceMgr &SM,
                           Lexer *PP, const SourceLocation& Pos,
                           VerifyDiagnosticConsumer::DirectiveStatus &Status) {
  DiagnosticsEngine &Diags = PP->getDiagnostics();

  // A single comment may contain multiple directives.
  bool FoundDirective = false;
  for (ParseHelper PH(S); !PH.Done();) {
    // Search for token: expected
    if (!PH.Search("expected", true))
      break;
    PH.Advance();

    // Next token: -
    if (!PH.Next("-"))
      continue;
    PH.Advance();

    // Next token: { error | warning | note }
    DirectiveList* DL = NULL;
    if (PH.Next("error"))
      DL = ED ? &ED->Errors : NULL;
    else if (PH.Next("warning"))
      DL = ED ? &ED->Warnings : NULL;
    else if (PH.Next("note"))
      DL = ED ? &ED->Notes : NULL;
    else if (PH.Next("no-diagnostics")) {
      if (Status == VerifyDiagnosticConsumer::HasOtherExpectedDirectives) {
        Diags.Report(Pos, diag::err_verify_invalid_no_diags)
          << /*IsExpectedNoDiagnostics=*/true;
      }
      else
        Status = VerifyDiagnosticConsumer::HasExpectedNoDiagnostics;
      continue;
    } else
      continue;
    PH.Advance();

    if (Status == VerifyDiagnosticConsumer::HasExpectedNoDiagnostics) {
      Diags.Report(Pos, diag::err_verify_invalid_no_diags)
        << /*IsExpectedNoDiagnostics=*/false;
      continue;
    }
    Status = VerifyDiagnosticConsumer::HasOtherExpectedDirectives;

    // If a directive has been found but we're not interested
    // in storing the directive information, return now.
    if (!DL)
      return true;

    // Default directive kind.
    bool RegexKind = false;
    const char* KindStr = "string";

    // Next optional token: -
    if (PH.Next("-re")) {
      PH.Advance();
      RegexKind = true;
      KindStr = "regex";
    }

    // Next optional token: @
    SourceLocation ExpectedLoc;
    if (!PH.Next("@")) {
      ExpectedLoc = Pos;
    } else {
      PH.Advance();
      unsigned Line = 0;
      bool FoundPlus = PH.Next("+");
      if (FoundPlus || PH.Next("-")) {
        // Relative to current line.
        PH.Advance();
        bool Invalid = false;
        unsigned ExpectedLine = SM.FindLineNumber(Pos);
        if (!Invalid && PH.Next(Line) && (FoundPlus || Line < ExpectedLine)) {
          if (FoundPlus) ExpectedLine += Line;
          else ExpectedLine -= Line;
          ExpectedLoc = translateLine(SM,SM.FindBufferContainingLoc(Pos), ExpectedLine);
        }
      } else if (PH.Next(Line)) {
        // Absolute line number.
        if (Line > 0)
          ExpectedLoc = translateLine(SM,SM.FindBufferContainingLoc(Pos), Line);
      }

      if (!ExpectedLoc.isValid()) {
        Diags.Report(getLocWithOffset(Pos,PH.C-PH.Begin),
                     diag::err_verify_missing_line) << KindStr;
        continue;
      }
      PH.Advance();
    }

    // Skip optional whitespace.
    PH.SkipWhitespace();

    // Next optional token: positive integer or a '+'.
    unsigned Min = 1;
    unsigned Max = 1;
    if (PH.Next(Min)) {
      PH.Advance();
      // A positive integer can be followed by a '+' meaning min
      // or more, or by a '-' meaning a range from min to max.
      if (PH.Next("+")) {
        Max = Directive::MaxCount;
        PH.Advance();
      } else if (PH.Next("-")) {
        PH.Advance();
        if (!PH.Next(Max) || Max < Min) {
          Diags.Report(getLocWithOffset(Pos,PH.C-PH.Begin),
                       diag::err_verify_invalid_range) << KindStr;
          continue;
        }
        PH.Advance();
      } else {
        Max = Min;
      }
    } else if (PH.Next("+")) {
      // '+' on its own means "1 or more".
      Max = Directive::MaxCount;
      PH.Advance();
    }

    // Skip optional whitespace.
    PH.SkipWhitespace();

    // Next token: {{
    if (!PH.Next("{{")) {
      Diags.Report(getLocWithOffset(Pos,PH.C-PH.Begin),
                   diag::err_verify_missing_start) << KindStr;
      continue;
    }
    PH.Advance();
    const char* const ContentBegin = PH.C; // mark content begin

    // Search for token: }}
    if (!PH.Search("}}")) {
      Diags.Report(getLocWithOffset(Pos,PH.C-PH.Begin),
                   diag::err_verify_missing_end) << KindStr;
      continue;
    }
    const char* const ContentEnd = PH.P; // mark content end
    PH.Advance();

    // Build directive text; convert \n to newlines.
    std::string Text;
    StringRef NewlineStr = "\\n";
    StringRef Content(ContentBegin, ContentEnd-ContentBegin);
    size_t CPos = 0;
    size_t FPos;
    while ((FPos = Content.find(NewlineStr, CPos)) != StringRef::npos) {
      Text += Content.substr(CPos, FPos-CPos);
      Text += '\n';
      CPos = FPos + NewlineStr.size();
    }
    if (Text.empty())
      Text.assign(ContentBegin, ContentEnd);

    // Construct new directive.
    Directive *D = Directive::create(RegexKind, Pos, ExpectedLoc, Text,
                                     Min, Max);
    std::string Error;
    if (D->isValid(Error)) {
      DL->push_back(D);
      FoundDirective = true;
    } else {
      Diags.Report(getLocWithOffset(Pos,ContentBegin-PH.Begin),
                   diag::err_verify_invalid_content)
        << KindStr << Error;
    }
  }

  return FoundDirective;
}