1 files changed, 255 insertions, 0 deletions
diff --git a/intl/locale/nsLanguageAtomService.cpp b/intl/locale/nsLanguageAtomService.cpp
new file mode 100644
index 0000000000..4a9d9b92d2
--- /dev/null
+++ b/intl/locale/nsLanguageAtomService.cpp
@@ -0,0 +1,255 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsLanguageAtomService.h"
+#include "nsUConvPropertySearch.h"
+#include "nsUnicharUtils.h"
+#include "nsAtom.h"
+#include "nsGkAtoms.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Encoding.h"
+#include "mozilla/intl/Locale.h"
+#include "mozilla/intl/OSPreferences.h"
+#include "mozilla/ServoBindings.h"
+#include "mozilla/ServoUtils.h"
+
+using namespace mozilla;
+using mozilla::intl::OSPreferences;
+
+static constexpr nsUConvProp encodingsGroups[] = {
+#include "encodingsgroups.properties.h"
+};
+
+// List of mozilla internal x-* tags that map to themselves (see bug 256257)
+static constexpr nsStaticAtom* kLangGroups[] = {
+    // This list must be sorted!
+    nsGkAtoms::x_armn,  nsGkAtoms::x_cyrillic, nsGkAtoms::x_devanagari,
+    nsGkAtoms::x_geor,  nsGkAtoms::x_math,     nsGkAtoms::x_tamil,
+    nsGkAtoms::Unicode, nsGkAtoms::x_western
+    // These self-mappings are not necessary unless somebody use them to specify
+    // lang in (X)HTML/XML documents, which they shouldn't. (see bug 256257)
+    // x-beng=x-beng
+    // x-cans=x-cans
+    // x-ethi=x-ethi
+    // x-guru=x-guru
+    // x-gujr=x-gujr
+    // x-khmr=x-khmr
+    // x-mlym=x-mlym
+};
+
+// Map ISO 15924 script codes from BCP47 lang tag to mozilla's langGroups.
+static constexpr struct {
+  const char* mTag;
+  nsStaticAtom* mAtom;
+} kScriptLangGroup[] = {
+    // This list must be sorted by script code!
+    {"Arab", nsGkAtoms::ar},
+    {"Armn", nsGkAtoms::x_armn},
+    {"Beng", nsGkAtoms::x_beng},
+    {"Cans", nsGkAtoms::x_cans},
+    {"Cyrl", nsGkAtoms::x_cyrillic},
+    {"Deva", nsGkAtoms::x_devanagari},
+    {"Ethi", nsGkAtoms::x_ethi},
+    {"Geok", nsGkAtoms::x_geor},
+    {"Geor", nsGkAtoms::x_geor},
+    {"Grek", nsGkAtoms::el},
+    {"Gujr", nsGkAtoms::x_gujr},
+    {"Guru", nsGkAtoms::x_guru},
+    {"Hang", nsGkAtoms::ko},
+    // Hani is not mapped to a specific langGroup, we prefer to look at the
+    // primary language subtag in this case
+    {"Hans", nsGkAtoms::Chinese},
+    // Hant is special-cased in code
+    // Hant=zh-HK
+    // Hant=zh-TW
+    {"Hebr", nsGkAtoms::he},
+    {"Hira", nsGkAtoms::Japanese},
+    {"Jpan", nsGkAtoms::Japanese},
+    {"Kana", nsGkAtoms::Japanese},
+    {"Khmr", nsGkAtoms::x_khmr},
+    {"Knda", nsGkAtoms::x_knda},
+    {"Kore", nsGkAtoms::ko},
+    {"Latn", nsGkAtoms::x_western},
+    {"Mlym", nsGkAtoms::x_mlym},
+    {"Orya", nsGkAtoms::x_orya},
+    {"Sinh", nsGkAtoms::x_sinh},
+    {"Taml", nsGkAtoms::x_tamil},
+    {"Telu", nsGkAtoms::x_telu},
+    {"Thai", nsGkAtoms::th},
+    {"Tibt", nsGkAtoms::x_tibt}};
+
+static UniquePtr<nsLanguageAtomService> gLangAtomService;
+
+// static
+nsLanguageAtomService* nsLanguageAtomService::GetService() {
+  if (!gLangAtomService) {
+    gLangAtomService = MakeUnique<nsLanguageAtomService>();
+  }
+  return gLangAtomService.get();
+}
+
+// static
+void nsLanguageAtomService::Shutdown() { gLangAtomService = nullptr; }
+
+nsStaticAtom* nsLanguageAtomService::LookupLanguage(
+    const nsACString& aLanguage) {
+  nsAutoCString lowered(aLanguage);
+  ToLowerCase(lowered);
+
+  RefPtr<nsAtom> lang = NS_Atomize(lowered);
+  return GetLanguageGroup(lang);
+}
+
+already_AddRefed<nsAtom> nsLanguageAtomService::LookupCharSet(
+    NotNull<const Encoding*> aEncoding) {
+  nsAutoCString charset;
+  aEncoding->Name(charset);
+  nsAutoCString group;
+  if (NS_FAILED(nsUConvPropertySearch::SearchPropertyValue(
+          encodingsGroups, ArrayLength(encodingsGroups), charset, group))) {
+    return RefPtr<nsAtom>(nsGkAtoms::Unicode).forget();
+  }
+  return NS_Atomize(group);
+}
+
+nsAtom* nsLanguageAtomService::GetLocaleLanguage() {
+  do {
+    if (!mLocaleLanguage) {
+      AutoTArray<nsCString, 10> regionalPrefsLocales;
+      if (NS_SUCCEEDED(OSPreferences::GetInstance()->GetRegionalPrefsLocales(
+              regionalPrefsLocales))) {
+        // use lowercase for all language atoms
+        ToLowerCase(regionalPrefsLocales[0]);
+        mLocaleLanguage = NS_Atomize(regionalPrefsLocales[0]);
+      } else {
+        nsAutoCString locale;
+        OSPreferences::GetInstance()->GetSystemLocale(locale);
+
+        ToLowerCase(locale);  // use lowercase for all language atoms
+        mLocaleLanguage = NS_Atomize(locale);
+      }
+    }
+  } while (0);
+
+  return mLocaleLanguage;
+}
+
+nsStaticAtom* nsLanguageAtomService::GetLanguageGroup(nsAtom* aLanguage,
+                                                      bool* aNeedsToCache) {
+  if (aNeedsToCache) {
+    if (nsStaticAtom* atom = mLangToGroup.Get(aLanguage)) {
+      return atom;
+    }
+    *aNeedsToCache = true;
+    return nullptr;
+  }
+
+  return mLangToGroup.LookupOrInsertWith(aLanguage, [&] {
+    AssertIsMainThreadOrServoFontMetricsLocked();
+    return GetUncachedLanguageGroup(aLanguage);
+  });
+}
+
+nsStaticAtom* nsLanguageAtomService::GetUncachedLanguageGroup(
+    nsAtom* aLanguage) const {
+  nsAutoCString langStr;
+  aLanguage->ToUTF8String(langStr);
+  ToLowerCase(langStr);
+
+  if (langStr[0] == 'x' && langStr[1] == '-') {
+    // Internal x-* langGroup codes map to themselves (see bug 256257)
+    for (nsStaticAtom* langGroup : kLangGroups) {
+      if (langGroup == aLanguage) {
+        return langGroup;
+      }
+      if (aLanguage->IsAsciiLowercase()) {
+        continue;
+      }
+      // Do the slow ascii-case-insensitive comparison just if needed.
+      nsDependentAtomString string(langGroup);
+      if (string.EqualsASCII(langStr.get(), langStr.Length())) {
+        return langGroup;
+      }
+    }
+  } else {
+    // If the lang code can be parsed as BCP47, look up its (likely) script.
+
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1618034:
+    // First strip any private subtags that would cause Locale to reject the
+    // tag as non-wellformed.
+    nsACString::const_iterator start, end;
+    langStr.BeginReading(start);
+    langStr.EndReading(end);
+    if (FindInReadable("-x-"_ns, start, end)) {
+      // The substring we want ends at the beginning of the "-x-" subtag.
+      langStr.Truncate(start.get() - langStr.BeginReading());
+    }
+
+    intl::Locale loc;
+    auto result = intl::LocaleParser::TryParse(langStr, loc);
+    if (!result.isOk()) {
+      // Did the author (wrongly) use '_' instead of '-' to separate subtags?
+      // If so, fix it up and re-try parsing.
+      if (langStr.Contains('_')) {
+        langStr.ReplaceChar('_', '-');
+
+        // Throw away the partially parsed locale and re-start parsing.
+        loc = {};
+        result = intl::LocaleParser::TryParse(langStr, loc);
+      }
+    }
+    if (result.isOk() && loc.Canonicalize().isOk()) {
+      // Fill in script subtag if not present.
+      if (loc.Script().Missing()) {
+        if (loc.AddLikelySubtags().isErr()) {
+          // Fall back to x-unicode if no match was found
+          return nsGkAtoms::Unicode;
+        }
+      }
+      // Traditional Chinese has separate prefs for Hong Kong / Taiwan;
+      // check the region subtag.
+      if (loc.Script().EqualTo("Hant")) {
+        if (loc.Region().EqualTo("HK")) {
+          return nsGkAtoms::HongKongChinese;
+        }
+        return nsGkAtoms::Taiwanese;
+      }
+      // Search list of known script subtags that map to langGroup codes.
+      size_t foundIndex;
+      Span<const char> scriptAsSpan = loc.Script().Span();
+      nsDependentCSubstring script(scriptAsSpan.data(), scriptAsSpan.size());
+      if (BinarySearchIf(
+              kScriptLangGroup, 0, ArrayLength(kScriptLangGroup),
+              [script](const auto& entry) -> int {
+                return Compare(script, nsDependentCString(entry.mTag));
+              },
+              &foundIndex)) {
+        return kScriptLangGroup[foundIndex].mAtom;
+      }
+      // Script subtag was not recognized (includes "Hani"); check the language
+      // subtag for CJK possibilities so that we'll prefer the appropriate font
+      // rather than falling back to the browser's hardcoded preference.
+      if (loc.Language().EqualTo("zh")) {
+        if (loc.Region().EqualTo("HK")) {
+          return nsGkAtoms::HongKongChinese;
+        }
+        if (loc.Region().EqualTo("TW")) {
+          return nsGkAtoms::Taiwanese;
+        }
+        return nsGkAtoms::Chinese;
+      }
+      if (loc.Language().EqualTo("ja")) {
+        return nsGkAtoms::Japanese;
+      }
+      if (loc.Language().EqualTo("ko")) {
+        return nsGkAtoms::ko;
+      }
+    }
+  }
+
+  // Fall back to x-unicode if no match was found
+  return nsGkAtoms::Unicode;
+}