//===--- FormatTokenLexer.h - Format C++ code ----------------*- C++ ----*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains FormatTokenLexer, which tokenizes a source file
/// into a token stream suitable for ClangFormat.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LIB_FORMAT_FORMATTOKENLEXER_H
#define LLVM_CLANG_LIB_FORMAT_FORMATTOKENLEXER_H

#include "Encoding.h"
#include "FormatToken.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Format/Format.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/Support/Regex.h"

#include <stack>

namespace clang {
namespace format {

enum LexerState {
  NORMAL,
  TEMPLATE_STRING,
  TOKEN_STASHED,
};

class FormatTokenLexer {
public:
  FormatTokenLexer(const SourceManager &SourceMgr, FileID ID, unsigned Column,
                   const FormatStyle &Style, encoding::Encoding Encoding);

  ArrayRef<FormatToken *> lex();

  const AdditionalKeywords &getKeywords() { return Keywords; }

private:
  void tryMergePreviousTokens();

  bool tryMergeLessLess();
  bool tryMergeNSStringLiteral();
  bool tryMergeJSPrivateIdentifier();
  bool tryMergeCSharpVerbatimStringLiteral();
  bool tryMergeCSharpKeywordVariables();
  bool tryMergeCSharpNullConditionals();
  bool tryMergeCSharpDoubleQuestion();
  bool tryTransformCSharpForEach();

  bool tryMergeTokens(ArrayRef<tok::TokenKind> Kinds, TokenType NewType);

  // Returns \c true if \p Tok can only be followed by an operand in JavaScript.
  bool precedesOperand(FormatToken *Tok);

  bool canPrecedeRegexLiteral(FormatToken *Prev);

  // Tries to parse a JavaScript Regex literal starting at the current token,
  // if that begins with a slash and is in a location where JavaScript allows
  // regex literals. Changes the current token to a regex literal and updates
  // its text if successful.
  void tryParseJSRegexLiteral();

  // Handles JavaScript template strings.
  //
  // JavaScript template strings use backticks ('`') as delimiters, and allow
  // embedding expressions nested in ${expr-here}. Template strings can be
  // nested recursively, i.e. expressions can contain template strings in turn.
  //
  // The code below parses starting from a backtick, up to a closing backtick or
  // an opening ${. It also maintains a stack of lexing contexts to handle
  // nested template parts by balancing curly braces.
  void handleTemplateStrings();

  void tryParsePythonComment();

  bool tryMerge_TMacro();

  bool tryMergeConflictMarkers();

  FormatToken *getStashedToken();

  FormatToken *getNextToken();

  FormatToken *FormatTok;
  bool IsFirstToken;
  std::stack<LexerState> StateStack;
  unsigned Column;
  unsigned TrailingWhitespace;
  std::unique_ptr<Lexer> Lex;
  const SourceManager &SourceMgr;
  FileID ID;
  const FormatStyle &Style;
  IdentifierTable IdentTable;
  AdditionalKeywords Keywords;
  encoding::Encoding Encoding;
  llvm::SpecificBumpPtrAllocator<FormatToken> Allocator;
  // Index (in 'Tokens') of the last token that starts a new line.
  unsigned FirstInLineIndex;
  SmallVector<FormatToken *, 16> Tokens;

  llvm::SmallMapVector<IdentifierInfo *, TokenType, 8> Macros;

  bool FormattingDisabled;

  llvm::Regex MacroBlockBeginRegex;
  llvm::Regex MacroBlockEndRegex;

  void readRawToken(FormatToken &Tok);

  void resetLexer(unsigned Offset);
};

} // namespace format
} // namespace clang

#endif