1 files changed, 91 insertions, 0 deletions
diff --git a/js/src/builtin/intl/LanguageTag.h b/js/src/builtin/intl/LanguageTag.h
new file mode 100644
index 0000000000..e896411e19
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+++ b/js/src/builtin/intl/LanguageTag.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * 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/. */
+
+/* Structured representation of Unicode locale IDs used with Intl functions. */
+
+#ifndef builtin_intl_LanguageTag_h
+#define builtin_intl_LanguageTag_h
+
+#include "mozilla/intl/Locale.h"
+#include "mozilla/Span.h"
+
+#include "js/Result.h"
+#include "js/RootingAPI.h"
+
+struct JS_PUBLIC_API JSContext;
+class JSLinearString;
+class JS_PUBLIC_API JSString;
+class JS_PUBLIC_API JSTracer;
+
+namespace js {
+
+namespace intl {
+
+/**
+ * Parse a string Unicode BCP 47 locale identifier. If successful, store in
+ * |result| and return true. Otherwise return false.
+ */
+[[nodiscard]] bool ParseLocale(JSContext* cx, JS::Handle<JSLinearString*> str,
+                               mozilla::intl::Locale& result);
+
+/**
+ * Parse a string as a standalone |language| tag. If |str| is a standalone
+ * language tag, store it in |result| and return true. Otherwise return false.
+ */
+[[nodiscard]] bool ParseStandaloneLanguageTag(
+    JS::Handle<JSLinearString*> str, mozilla::intl::LanguageSubtag& result);
+
+/**
+ * Parse a string as a standalone |script| tag. If |str| is a standalone script
+ * tag, store it in |result| and return true. Otherwise return false.
+ */
+[[nodiscard]] bool ParseStandaloneScriptTag(
+    JS::Handle<JSLinearString*> str, mozilla::intl::ScriptSubtag& result);
+
+/**
+ * Parse a string as a standalone |region| tag. If |str| is a standalone region
+ * tag, store it in |result| and return true. Otherwise return false.
+ */
+[[nodiscard]] bool ParseStandaloneRegionTag(
+    JS::Handle<JSLinearString*> str, mozilla::intl::RegionSubtag& result);
+
+/**
+ * Parse a string as an ISO-639 language code. Return |nullptr| in the result if
+ * the input could not be parsed or the canonical form of the resulting language
+ * tag contains more than a single language subtag.
+ */
+JS::Result<JSString*> ParseStandaloneISO639LanguageTag(
+    JSContext* cx, JS::Handle<JSLinearString*> str);
+
+class UnicodeExtensionKeyword final {
+  char key_[mozilla::intl::LanguageTagLimits::UnicodeKeyLength];
+  JSLinearString* type_;
+
+ public:
+  using UnicodeKey =
+      const char (&)[mozilla::intl::LanguageTagLimits::UnicodeKeyLength + 1];
+  using UnicodeKeySpan =
+      mozilla::Span<const char,
+                    mozilla::intl::LanguageTagLimits::UnicodeKeyLength>;
+
+  UnicodeExtensionKeyword(UnicodeKey key, JSLinearString* type)
+      : key_{key[0], key[1]}, type_(type) {}
+
+  UnicodeKeySpan key() const { return {key_, sizeof(key_)}; }
+  JSLinearString* type() const { return type_; }
+
+  void trace(JSTracer* trc);
+};
+
+[[nodiscard]] extern bool ApplyUnicodeExtensionToTag(
+    JSContext* cx, mozilla::intl::Locale& tag,
+    JS::HandleVector<UnicodeExtensionKeyword> keywords);
+
+}  // namespace intl
+
+}  // namespace js
+
+#endif /* builtin_intl_LanguageTag_h */