Expose getCanonicalLocales() for Intl object

src/js/i18n.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // ECMAScript 402 API implementation.
 
 /**
  * Intl object is a single object that has some named properties,
  * all of which are constructors.
  */
@@ skipping 700 matching lines @@
           ((lowercasedPart !== 'es' &&
             lowercasedPart !== 'of' && lowercasedPart !== 'au') ?
           toTitleCaseWord(part) : lowercasedPart);
     }
   }
   return result;
 }
 
 /**
  * Canonicalizes the language tag, or throws in case the tag is invalid.
+ * ECMA 402 9.2.1 steps 7.c ii ~ v.
  */
 function canonicalizeLanguageTag(localeID) {
   // null is typeof 'object' so we have to do extra check.
   if ((!IS_STRING(localeID) && !IS_RECEIVER(localeID)) ||
       IS_NULL(localeID)) {
     throw %make_type_error(kLanguageID);
   }
 
   // Optimize for the most common case; a language code alone in
   // the canonical form/lowercase (e.g. "en", "fil").
   if (IS_STRING(localeID) &&
       !IS_NULL(InternalRegExpMatch(/^[a-z]{2,3}$/, localeID))) {
     return localeID;
   }
 
   var localeString = TO_STRING(localeID);
 
-  if (isValidLanguageTag(localeString) === false) {
+  if (isStructuallyValidLanguageTag(localeString) === false) {
     throw %make_range_error(kInvalidLanguageTag, localeString);
   }
 
+  // ECMA 402 6.2.3
   var tag = %CanonicalizeLanguageTag(localeString);
+  // TODO(jshin): This should not happen because the structual validity
+  // is already checked. If that's the case, remove this.
   if (tag === 'invalid-tag') {
     throw %make_range_error(kInvalidLanguageTag, localeString);
   }
 
   return tag;
 }
 
 
 /**
  * Returns an array where all locales are canonicalized and duplicates removed.
  * Throws on locales that are not well formed BCP47 tags.
+ * ECMA 402 8.2.1 steps 1 (ECMA 402 9.2.1) and 2.
  */
 function initializeLocaleList(locales) {
   var seen = new InternalArray();
   if (!IS_UNDEFINED(locales)) {
     // We allow single string localeID.
     if (typeof locales === 'string') {
       %_Call(ArrayPush, seen, canonicalizeLanguageTag(locales));
       return freezeArray(seen);
     }
 
     var o = TO_OBJECT(locales);
-    var len = TO_UINT32(o.length);
+    var len = TO_LENGTH(o.length);
 
     for (var k = 0; k < len; k++) {
+      // ECMA 402 9.2.1 step 7a converts 'k' to String. Does it make
+      // any difference?
       if (k in o) {
         var value = o[k];
 
         var tag = canonicalizeLanguageTag(value);
 
         if (%_Call(ArrayIndexOf, seen, tag) === -1) {
           %_Call(ArrayPush, seen, tag);

[jungshik at Google, 2016/08/11 20:56:40]

intl402/Intl/getCanonicalLocales/overriden-push.js tests if 'push' is used by
overriding Array.prototype.push. However, v8 doesn't throw because we're using
InternalArray. So, there should not be an issue (even though we don't follow the
spec to its letters: build a list and convert to an array at the end). 

         }
       }
     }
   }
 
   return freezeArray(seen);
 }
 
 
 /**
- * Validates the language tag. Section 2.2.9 of the bcp47 spec
- * defines a valid tag.
+ * Check the structual Validity of the language tag per ECMA 402 6.2.2:
+ *   - Well-formed per RFC 5646 2.1
+ *   - There are no duplicate variant subtags
+ *   - There are no duplicate singletion (extension) subtags
+ *
+ * One extra-check is done (from RFC 5646 2.2.9): the tag is compared
+ * against the list of grandfathered tags. However, subtags for
+ * primary/extended language, script, region, variant are not checked
+ * against the IANA language subtag registry.
  *
  * ICU is too permissible and lets invalid tags, like
  * hant-cmn-cn, through.
  *
  * Returns false if the language tag is invalid.
  */
-function isValidLanguageTag(locale) {
+function isStructuallyValidLanguageTag(locale) {
   // Check if it's well-formed, including grandfadered tags.
   if (IS_NULL(InternalRegExpMatch(GetLanguageTagRE(), locale))) {
     return false;
   }
 
   // Just return if it's a x- form. It's all private.
   if (%_Call(StringIndexOf, locale, 'x-') === 0) {
     return true;
   }
 
@@ skipping 74 matching lines @@
 var resolvedAccessor = {
   get() {
     %IncrementUseCounter(kIntlResolved);
     return this[resolvedSymbol];
   },
   set(value) {
     this[resolvedSymbol] = value;
   }
 };
 
+// ECMA 402 section 8.2.1
+InstallFunction(Intl, 'getCanonicalLocales', function(locales) {
+    if (!IS_UNDEFINED(new.target)) {
+      throw %make_type_error(kOrdinaryFunctionCalledAsConstructor);
+    }
+
+    return initializeLocaleList(locales);
+  }
+);
+
 /**
  * Initializes the given object so it's a valid Collator instance.
  * Useful for subclassing.
  */
 function initializeCollator(collator, locales, options) {
   if (%IsInitializedIntlObject(collator)) {
     throw %make_type_error(kReinitializeIntl, "Collator");
   }
 
   if (IS_UNDEFINED(options)) {
@@ skipping 1348 matching lines @@
   }
 );
 
 utils.Export(function(to) {
   to.AddBoundMethod = AddBoundMethod;
   to.IntlParseDate = IntlParseDate;
   to.IntlParseNumber = IntlParseNumber;
 });
 
 })