1 files changed, 163 insertions, 0 deletions
diff --git a/intl/unicharutil/util/ICUUtils.cpp b/intl/unicharutil/util/ICUUtils.cpp
new file mode 100644
index 0000000000..4ee3bf5f15
--- /dev/null
+++ b/intl/unicharutil/util/ICUUtils.cpp
@@ -0,0 +1,163 @@
+/* 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/. */
+
+#ifdef MOZILLA_INTERNAL_API
+
+#  include "mozilla/Assertions.h"
+#  include "mozilla/UniquePtr.h"
+
+#  include "ICUUtils.h"
+#  include "mozilla/StaticPrefs_dom.h"
+#  include "mozilla/intl/LocaleService.h"
+#  include "mozilla/intl/FormatBuffer.h"
+#  include "mozilla/intl/NumberFormat.h"
+#  include "mozilla/intl/NumberParser.h"
+#  include "nsIContent.h"
+#  include "mozilla/dom/Document.h"
+#  include "nsString.h"
+
+using namespace mozilla;
+using mozilla::intl::LocaleService;
+
+void ICUUtils::LanguageTagIterForContent::GetNext(nsACString& aBCP47LangTag) {
+  if (mCurrentFallbackIndex < 0) {
+    mCurrentFallbackIndex = 0;
+    // Try the language specified by a 'lang'/'xml:lang' attribute on mContent
+    // or any ancestor, if such an attribute is specified:
+    nsAutoString lang;
+    mContent->GetLang(lang);
+    if (!lang.IsEmpty()) {
+      CopyUTF16toUTF8(lang, aBCP47LangTag);
+      return;
+    }
+  }
+
+  if (mCurrentFallbackIndex < 1) {
+    mCurrentFallbackIndex = 1;
+    // Else try the language specified by any Content-Language HTTP header or
+    // pragma directive:
+    nsAutoString lang;
+    mContent->OwnerDoc()->GetContentLanguage(lang);
+    if (!lang.IsEmpty()) {
+      CopyUTF16toUTF8(lang, aBCP47LangTag);
+      return;
+    }
+  }
+
+  if (mCurrentFallbackIndex < 2) {
+    mCurrentFallbackIndex = 2;
+    // Else take the app's locale:
+
+    nsAutoCString appLocale;
+    LocaleService::GetInstance()->GetAppLocaleAsBCP47(aBCP47LangTag);
+    return;
+  }
+
+  // TODO: Probably not worth it, but maybe have a fourth fallback to using
+  // the OS locale?
+
+  aBCP47LangTag.Truncate();  // Signal iterator exhausted
+}
+
+/* static */
+bool ICUUtils::LocalizeNumber(double aValue,
+                              LanguageTagIterForContent& aLangTags,
+                              nsAString& aLocalizedValue) {
+  MOZ_ASSERT(aLangTags.IsAtStart(), "Don't call Next() before passing");
+
+  nsAutoCString langTag;
+  aLangTags.GetNext(langTag);
+
+  intl::NumberFormatOptions options;
+  if (StaticPrefs::dom_forms_number_grouping()) {
+    options.mGrouping = intl::NumberFormatOptions::Grouping::Always;
+  } else {
+    options.mGrouping = intl::NumberFormatOptions::Grouping::Never;
+  }
+
+  // ICU default is a maximum of 3 significant fractional digits. We don't
+  // want that limit, so we set it to the maximum that a double can represent
+  // (14-16 decimal fractional digits).
+  options.mFractionDigits = Some(std::make_pair(0, 16));
+
+  while (!langTag.IsEmpty()) {
+    auto result = intl::NumberFormat::TryCreate(langTag.get(), options);
+    if (result.isErr()) {
+      aLangTags.GetNext(langTag);
+      continue;
+    }
+    UniquePtr<intl::NumberFormat> nf = result.unwrap();
+    intl::nsTStringToBufferAdapter adapter(aLocalizedValue);
+    if (nf->format(aValue, adapter).isOk()) {
+      return true;
+    }
+
+    aLangTags.GetNext(langTag);
+  }
+  return false;
+}
+
+/* static */
+double ICUUtils::ParseNumber(nsAString& aValue,
+                             LanguageTagIterForContent& aLangTags) {
+  MOZ_ASSERT(aLangTags.IsAtStart(), "Don't call Next() before passing");
+
+  if (aValue.IsEmpty()) {
+    return std::numeric_limits<float>::quiet_NaN();
+  }
+
+  uint32_t length = aValue.Length();
+
+  nsAutoCString langTag;
+  aLangTags.GetNext(langTag);
+  while (!langTag.IsEmpty()) {
+    auto createResult = intl::NumberParser::TryCreate(
+        langTag.get(), StaticPrefs::dom_forms_number_grouping());
+    if (createResult.isErr()) {
+      aLangTags.GetNext(langTag);
+      continue;
+    }
+    UniquePtr<intl::NumberParser> np = createResult.unwrap();
+
+    static_assert(sizeof(UChar) == 2 && sizeof(nsAString::char_type) == 2,
+                  "Unexpected character size - the following cast is unsafe");
+    auto parseResult = np->ParseDouble(
+        mozilla::Span<const char16_t>(PromiseFlatString(aValue).get(), length));
+    if (parseResult.isOk()) {
+      std::pair<double, int32_t> parsed = parseResult.unwrap();
+      if (parsed.second == static_cast<int32_t>(length)) {
+        return parsed.first;
+      }
+    }
+    aLangTags.GetNext(langTag);
+  }
+  return std::numeric_limits<float>::quiet_NaN();
+}
+
+/* static */
+void ICUUtils::AssignUCharArrayToString(UChar* aICUString, int32_t aLength,
+                                        nsAString& aMozString) {
+  // Both ICU's UnicodeString and Mozilla's nsAString use UTF-16, so we can
+  // cast here.
+
+  static_assert(sizeof(UChar) == 2 && sizeof(nsAString::char_type) == 2,
+                "Unexpected character size - the following cast is unsafe");
+
+  aMozString.Assign((const nsAString::char_type*)aICUString, aLength);
+
+  NS_ASSERTION((int32_t)aMozString.Length() == aLength, "Conversion failed");
+}
+
+/* static */
+nsresult ICUUtils::ICUErrorToNsResult(const intl::ICUError aError) {
+  switch (aError) {
+    case intl::ICUError::OutOfMemory:
+      return NS_ERROR_OUT_OF_MEMORY;
+
+    default:
+      return NS_ERROR_FAILURE;
+  }
+}
+
+#endif /* MOZILLA_INTERNAL_API */