[intl] Return "UTC" instead of "Etc/UTC" or "Etc/GMT" as DefaultTimeZone

Refactoring the code dealing with TimeZone Canonicalization.
Change CanonicalizeTimeZoneName from return MaybeHandle<String> to Handle<String>
Move TimeZoneId from JSDateTimeFormat to Intl and return Handle<String> instead of Handle<Object>


Bug: v8:13112
Change-Id: I678b0e0d407e5e4e9dd8b7120c0e99e7e2d9c5ea
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3833435Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82505}

src/objects/intl-objects.cc

@@ -2822,21 +2822,37 @@ bool IsUnicodeStringValidTimeZoneName(const icu::UnicodeString& id) {
 }
 }  // namespace
 
-MaybeHandle<String> Intl::CanonicalizeTimeZoneName(Isolate* isolate,
-                                                   Handle<String> identifier) {
+Handle<String> Intl::CanonicalizeTimeZoneID(Isolate* isolate,
+                                            const icu::UnicodeString& id) {
   UErrorCode status = U_ZERO_ERROR;
-  std::string time_zone =
-      JSDateTimeFormat::CanonicalizeTimeZoneID(identifier->ToCString().get());
-  icu::UnicodeString time_zone_ustring =
-      icu::UnicodeString(time_zone.c_str(), -1, US_INV);
   icu::UnicodeString canonical;
-  icu::TimeZone::getCanonicalID(time_zone_ustring, canonical, status);
+  icu::TimeZone::getCanonicalID(id, canonical, status);
   CHECK(U_SUCCESS(status));
+  // In CLDR (http://unicode.org/cldr/trac/ticket/9943), Etc/UTC is made
+  // a separate timezone ID from Etc/GMT even though they're still the same
+  // timezone. We have Etc/UTC because 'UTC', 'Etc/Universal',
+  // 'Etc/Zulu' and others are turned to 'Etc/UTC' by ICU. Etc/GMT comes
+  // from Etc/GMT0, Etc/GMT+0, Etc/GMT-0, Etc/Greenwich.
+  // ecma402#sec-canonicalizetimezonename step 3
   if (canonical == UNICODE_STRING_SIMPLE("Etc/UTC") ||
       canonical == UNICODE_STRING_SIMPLE("Etc/GMT")) {
     return isolate->factory()->UTC_string();
   }
-  return Intl::ToString(isolate, canonical);
+  return Intl::ToString(isolate, canonical).ToHandleChecked();
+}
+
+Handle<String> Intl::CanonicalizeTimeZoneName(Isolate* isolate,
+                                              Handle<String> identifier) {
+  std::string time_zone =
+      JSDateTimeFormat::CanonicalizeTimeZoneID(identifier->ToCString().get());
+  return CanonicalizeTimeZoneID(
+      isolate, icu::UnicodeString(time_zone.c_str(), -1, US_INV));
+}
+
+Handle<String> Intl::TimeZoneId(Isolate* isolate, const icu::TimeZone& tz) {
+  icu::UnicodeString time_zone;
+  tz.getID(time_zone);
+  return Intl::CanonicalizeTimeZoneID(isolate, time_zone);
 }
 
 bool Intl::IsValidTimeZoneName(Isolate* isolate, Handle<String> id) {
@@ -2945,16 +2961,8 @@ Handle<String> Intl::SourceString(Isolate* isolate, FormatRangeSource source) {
 }
 
 Handle<String> Intl::DefaultTimeZone(Isolate* isolate) {
-  icu::UnicodeString id;
-  {
-    std::unique_ptr<icu::TimeZone> tz(icu::TimeZone::createDefault());
-    tz->getID(id);
-  }
-  UErrorCode status = U_ZERO_ERROR;
-  icu::UnicodeString canonical;
-  icu::TimeZone::getCanonicalID(id, canonical, status);
-  DCHECK(U_SUCCESS(status));
-  return Intl::ToString(isolate, canonical).ToHandleChecked();
+  std::unique_ptr<icu::TimeZone> tz(icu::TimeZone::createDefault());
+  return TimeZoneId(isolate, *tz);
 }
 
 namespace {

src/objects/intl-objects.h

@@ -390,8 +390,13 @@ class Intl {
   static std::vector<int64_t> GetTimeZonePossibleOffsetMilliseconds(
       Isolate* isolate, int32_t time_zone_index, int64_t time_ms);
 
-  V8_WARN_UNUSED_RESULT static MaybeHandle<String> CanonicalizeTimeZoneName(
-      Isolate* isolate, Handle<String> identifier);
+  static Handle<String> CanonicalizeTimeZoneName(Isolate* isolate,
+                                                 Handle<String> identifier);
+
+  static Handle<String> CanonicalizeTimeZoneID(
+      Isolate* isolate, const icu::UnicodeString& identifier);
+
+  static Handle<String> TimeZoneId(Isolate* isolate, const icu::TimeZone& tz);
 
   // ecma402/#sec-coerceoptionstoobject
   V8_WARN_UNUSED_RESULT static MaybeHandle<JSReceiver> CoerceOptionsToObject(

src/objects/js-date-time-format.cc

@@ -495,37 +495,6 @@ int FractionalSecondDigitsFromPattern(const std::string& pattern) {
 
 }  // namespace
 
-Handle<Object> JSDateTimeFormat::TimeZoneId(Isolate* isolate,
-                                            const icu::TimeZone& tz) {
-  Factory* factory = isolate->factory();
-  icu::UnicodeString time_zone;
-  tz.getID(time_zone);
-  UErrorCode status = U_ZERO_ERROR;
-  icu::UnicodeString canonical_time_zone;
-  icu::TimeZone::getCanonicalID(time_zone, canonical_time_zone, status);
-  Handle<Object> timezone_value;
-  if (U_SUCCESS(status)) {
-    // In CLDR (http://unicode.org/cldr/trac/ticket/9943), Etc/UTC is made
-    // a separate timezone ID from Etc/GMT even though they're still the same
-    // timezone. We have Etc/UTC because 'UTC', 'Etc/Universal',
-    // 'Etc/Zulu' and others are turned to 'Etc/UTC' by ICU. Etc/GMT comes
-    // from Etc/GMT0, Etc/GMT+0, Etc/GMT-0, Etc/Greenwich.
-    // ecma402#sec-canonicalizetimezonename step 3
-    if (canonical_time_zone == UNICODE_STRING_SIMPLE("Etc/UTC") ||
-        canonical_time_zone == UNICODE_STRING_SIMPLE("Etc/GMT")) {
-      timezone_value = factory->UTC_string();
-    } else {
-      ASSIGN_RETURN_ON_EXCEPTION_VALUE(
-          isolate, timezone_value, Intl::ToString(isolate, canonical_time_zone),
-          Handle<Object>());
-    }
-  } else {
-    // Somehow on Windows we will reach here.
-    timezone_value = factory->undefined_value();
-  }
-  return timezone_value;
-}
-
 namespace {
 Handle<String> GetCalendar(Isolate* isolate,
                            const icu::SimpleDateFormat& simple_date_format,
@@ -557,8 +526,8 @@ Handle<String> GetCalendar(Isolate* isolate,
 
 Handle<Object> GetTimeZone(Isolate* isolate,
                            const icu::SimpleDateFormat& simple_date_format) {
-  return JSDateTimeFormat::TimeZoneId(
-      isolate, simple_date_format.getCalendar()->getTimeZone());
+  return Intl::TimeZoneId(isolate,
+                          simple_date_format.getCalendar()->getTimeZone());
 }
 }  // namespace
 

src/objects/js-date-time-format.h

@@ -99,7 +99,6 @@ class JSDateTimeFormat
 
   V8_EXPORT_PRIVATE static const std::set<std::string>& GetAvailableLocales();
 
-  Handle<Object> static TimeZoneId(Isolate* isolate, const icu::TimeZone& tz);
   std::unique_ptr<icu::TimeZone> static CreateTimeZone(const char* timezone);
 
   V8_EXPORT_PRIVATE static std::string CanonicalizeTimeZoneID(

src/objects/js-temporal-objects.cc

@@ -4519,7 +4519,7 @@ bool IsValidTimeZoneName(Isolate* isolate, Handle<String> time_zone) {
 
 Handle<String> CanonicalizeTimeZoneName(Isolate* isolate,
                                         Handle<String> identifier) {
-  return Intl::CanonicalizeTimeZoneName(isolate, identifier).ToHandleChecked();
+  return Intl::CanonicalizeTimeZoneName(isolate, identifier);
 }
 
 #else   // V8_INTL_SUPPORT