tor-browser

The Tor Browser
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EncodingToLang.cpp (2199B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #include "mozilla/intl/EncodingToLang.h"
      7 #include "nsGkAtoms.h"
      8 #include "nsLanguageAtomService.h"
      9 
     10 using namespace mozilla;
     11 using namespace mozilla::intl;
     12 
     13 // Parallel arrays of Encoding and corresponding Lang atoms,
     14 // in rough order of frequency.
     15 
     16 // Unfortunately, the `mozilla::NotNull` hack that was used to
     17 // declare the encoding pointers in C++ does not allow putting
     18 // the pointers in a static array without a run-time initializer,
     19 // so our options are:
     20 // 1. Putting the pointers in a static array in Rust, at a distance.
     21 // 2. Run-time initializer.
     22 // 3. Using pointer pointers, as seen here.
     23 const mozilla::NotNull<const mozilla::Encoding*>*
     24    EncodingToLang::kEncodingsByRoughFrequency[] = {
     25 #define _(encoding, lang) &encoding,
     26 #include "EncodingsByFrequency.inc"
     27 #undef _
     28 };
     29 
     30 // This one isn't constant, as it gets adjusted during Initialize().
     31 // static
     32 nsAtom* EncodingToLang::sLangs[] = {
     33 #define _(encoding, lang) lang,
     34 #include "EncodingsByFrequency.inc"
     35 #undef _
     36 };
     37 
     38 // static
     39 nsAtom* EncodingToLang::Lookup(NotNull<const mozilla::Encoding*> aEncoding) {
     40  // Linear search should be fine, since in the vast, vast majority of cases,
     41  // the search stops at the first or second item.
     42  unsigned int i = 0;
     43  for (; i < std::size(kEncodingsByRoughFrequency); i++) {
     44    if (*kEncodingsByRoughFrequency[i] == aEncoding) {
     45      return sLangs[i];
     46    }
     47  }
     48  MOZ_ASSERT(false, "The encoding is always supposed to be found in the array");
     49  return sLangs[0];
     50 }
     51 
     52 // static
     53 void EncodingToLang::Initialize() {
     54  sLangs[0] = nsLanguageAtomService::GetService()->GetLocaleLanguage();
     55  // We logically hold a strong ref to the first occurrence
     56  // and a non-owning pointer to the rest.
     57  NS_ADDREF(sLangs[0]);
     58  for (size_t i = 1; i < std::size(sLangs); ++i) {
     59    if (!sLangs[i]) {
     60      sLangs[i] = sLangs[0];
     61    }
     62  }
     63 }
     64 
     65 // static
     66 void EncodingToLang::Shutdown() { NS_RELEASE(sLangs[0]); }