js/src/frontend/EitherParser.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /*
   8  * A variant-like class abstracting operations on a Parser with a given
   9  * ParseHandler but unspecified character type.
  10  */
  11
  12 #ifndef frontend_EitherParser_h
  13 #define frontend_EitherParser_h
  14
  15 #include "mozilla/Utf8.h"
  16 #include "mozilla/Variant.h"
  17
  18 #include <type_traits>
  19 #include <utility>
  20
  21 #include "frontend/Parser.h"
  22 #include "js/ColumnNumber.h"  // JS::LimitedColumnNumberOneOrigin
  23
  24 namespace js::frontend {
  25
  26 class EitherParser final {
  27   // Leave this as a variant, to promote good form until 8-bit parser
  28   // integration.
  29   mozilla::Variant<Parser<FullParseHandler, char16_t>* const,
  30                    Parser<FullParseHandler, mozilla::Utf8Unit>* const>
  31       parser;
  32
  33  public:
  34   template <class Parser>
  35   explicit EitherParser(Parser* parser) : parser(parser) {}
  36
  37   const ErrorReporter& errorReporter() const {
  38     return parser.match([](auto* parser) -> const frontend::ErrorReporter& {
  39       return parser->tokenStream;
  40     });
  41   }
  42
  43   void computeLineAndColumn(uint32_t offset, uint32_t* line,
  44                             JS::LimitedColumnNumberOneOrigin* column) const {
  45     return parser.match([offset, line, column](auto* parser) -> void {
  46       parser->tokenStream.computeLineAndColumn(offset, line, column);
  47     });
  48   }
  49
  50   ParserAtomsTable& parserAtoms() {
  51     auto& base = parser.match(
  52         [](auto* parser) -> frontend::ParserSharedBase& { return *parser; });
  53     return base.parserAtoms();
  54   }
  55 };
  56
  57 } /* namespace js::frontend */
  58
  59 #endif /* frontend_EitherParser_h */