[Temporal] Add PlainMonthDay.prototype.toJSON

Also add AO: TemporalMonthDayToString

Spec Text:
https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.tojson
https://tc39.es/proposal-temporal/#sec-temporal-temporalmonthdaytostring

Bug: v8:11544
Change-Id: Ibbc5b28a9c73474f7edc1b67c9beabf5bca54dbc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3437891Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80624}

src/builtins/builtins-temporal.cc

@@ -268,8 +268,6 @@ TO_BE_IMPLEMENTED(TemporalPlainMonthDayPrototypeWith)
 TO_BE_IMPLEMENTED(TemporalPlainMonthDayPrototypeEquals)
 /* Temporal #sec-temporal.plainmonthday.prototype.tostring */
 TO_BE_IMPLEMENTED(TemporalPlainMonthDayPrototypeToString)
-/* Temporal #sec-temporal.plainmonthday.tojson */
-TO_BE_IMPLEMENTED(TemporalPlainMonthDayPrototypeToJSON)
 /* Temporal #sec-temporal.plainmonthday.prototype.toplaindate */
 TO_BE_IMPLEMENTED(TemporalPlainMonthDayPrototypeToPlainDate)
 
@@ -601,6 +599,7 @@ TEMPORAL_GET_BY_FORWARD_CALENDAR(PlainMonthDay, MonthCode, monthCode)
 TEMPORAL_GET_BY_FORWARD_CALENDAR(PlainMonthDay, Day, day)
 TEMPORAL_PROTOTYPE_METHOD0(PlainMonthDay, GetISOFields, getISOFields)
 TEMPORAL_VALUE_OF(PlainMonthDay)
+TEMPORAL_PROTOTYPE_METHOD0(PlainMonthDay, ToJSON, toJSON)
 
 // ZonedDateTime
 

src/objects/js-temporal-objects.cc

@@ -2657,6 +2657,55 @@ MaybeHandle<String> TemporalDateToString(
   return builder.Finish().ToHandleChecked();
 }
 
+// #sec-temporal-temporalmonthdaytostring
+MaybeHandle<String> TemporalMonthDayToString(
+    Isolate* isolate, Handle<JSTemporalPlainMonthDay> month_day,
+    ShowCalendar show_calendar) {
+  // 1. Assert: Type(monthDay) is Object.
+  // 2. Assert: monthDay has an [[InitializedTemporalMonthDay]] internal slot.
+  IncrementalStringBuilder builder(isolate);
+  // 6. Let calendarID be ? ToString(monthDay.[[Calendar]]).
+  Handle<String> calendar_id;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate, calendar_id,
+      Object::ToString(isolate, handle(month_day->calendar(), isolate)),
+      String);
+  // 7. If showCalendar is "always" or if calendarID is not "iso8601", then
+  if (show_calendar == ShowCalendar::kAlways ||
+      !String::Equals(isolate, calendar_id,
+                      isolate->factory()->iso8601_string())) {
+    // a. Let year be ! PadISOYear(monthDay.[[ISOYear]]).
+    PadISOYear(&builder, month_day->iso_year());
+    // b. Set result to the string-concatenation of year, the code unit
+    // 0x002D (HYPHEN-MINUS), and result.
+    builder.AppendCharacter('-');
+  }
+  // 3. Let month be ToZeroPaddedDecimalString(monthDay.[[ISOMonth]], 2).
+  int32_t month = month_day->iso_month();
+  if (month < 10) {
+    builder.AppendCharacter('0');
+  }
+  builder.AppendInt(month);
+  // 5. Let result be the string-concatenation of month, the code unit 0x002D
+  // (HYPHEN-MINUS), and day.
+  builder.AppendCharacter('-');
+  // 4. Let day be ToZeroPaddedDecimalString(monthDay.[[ISODay]], 2).
+  int32_t day = month_day->iso_day();
+  if (day < 10) {
+    builder.AppendCharacter('0');
+  }
+  builder.AppendInt(day);
+  // 8. Let calendarString be ! FormatCalendarAnnotation(calendarID,
+  // showCalendar).
+  Handle<String> calendar_string =
+      FormatCalendarAnnotation(isolate, calendar_id, show_calendar);
+
+  // 9. Set result to the string-concatenation of result and calendarString.
+  builder.AppendString(calendar_string);
+  // 10. Return result.
+  return builder.Finish().ToHandleChecked();
+}
+
 // #sec-temporal-builtintimezonegetoffsetstringfor
 MaybeHandle<String> BuiltinTimeZoneGetOffsetStringFor(
     Isolate* isolate, Handle<JSReceiver> time_zone,
@@ -6657,7 +6706,10 @@ MaybeHandle<String> JSTemporalCalendar::MonthCode(
         Handle<JSTemporalPlainYearMonth>::cast(temporal_date_like)->iso_month();
   }
   IncrementalStringBuilder builder(isolate);
-  builder.AppendCString((month < 10) ? "M0" : "M");
+  builder.AppendCharacter('M');
+  if (month < 10) {
+    builder.AppendCharacter('0');
+  }
   builder.AppendInt(month);
 
   return builder.Finish();
@@ -7896,6 +7948,12 @@ MaybeHandle<JSReceiver> JSTemporalPlainMonthDay::GetISOFields(
   return fields;
 }
 
+// #sec-temporal.plainmonthday.prototype.tojson
+MaybeHandle<String> JSTemporalPlainMonthDay::ToJSON(
+    Isolate* isolate, Handle<JSTemporalPlainMonthDay> month_day) {
+  return TemporalMonthDayToString(isolate, month_day, ShowCalendar::kAuto);
+}
+
 MaybeHandle<JSTemporalPlainYearMonth> JSTemporalPlainYearMonth::Constructor(
     Isolate* isolate, Handle<JSFunction> target, Handle<HeapObject> new_target,
     Handle<Object> iso_year_obj, Handle<Object> iso_month_obj,

src/objects/js-temporal-objects.h

@@ -338,6 +338,10 @@ class JSTemporalPlainMonthDay
   V8_WARN_UNUSED_RESULT static MaybeHandle<JSReceiver> GetISOFields(
       Isolate* isolate, Handle<JSTemporalPlainMonthDay> month_day);
 
+  // #sec-temporal.plainmonthday.prototype.tojson
+  V8_WARN_UNUSED_RESULT static MaybeHandle<String> ToJSON(
+      Isolate* isolate, Handle<JSTemporalPlainMonthDay> month_day);
+
   DECL_PRINTER(JSTemporalPlainMonthDay)
 
   DEFINE_TORQUE_GENERATED_JS_TEMPORAL_YEAR_MONTH_DAY()

test/mjsunit/mjsunit.status

@@ -46,7 +46,6 @@
   # Temporal tests to be implemented
   # https://crbug.com/v8/11544
   'temporal/calendar-date-until': [FAIL],
-  'temporal/calendar-month-day-from-fields': [FAIL],
   'temporal/calendar-week-of-year': [FAIL],
   'temporal/calendar-year-month-from-fields': [FAIL],
   'temporal/duration-add': [FAIL],

test/test262/test262.status

@@ -1155,9 +1155,6 @@
   'built-ins/Temporal/PlainMonthDay/prototype/equals/calendars': [FAIL],
   'built-ins/Temporal/PlainMonthDay/prototype/equals/calendar-temporal-object': [FAIL],
   'built-ins/Temporal/PlainMonthDay/prototype/equals/infinity-throws-rangeerror': [FAIL],
-  'built-ins/Temporal/PlainMonthDay/prototype/toJSON/branding': [FAIL],
-  'built-ins/Temporal/PlainMonthDay/prototype/toJSON/calendarname': [FAIL],
-  'built-ins/Temporal/PlainMonthDay/prototype/toJSON/year-format': [FAIL],
   'built-ins/Temporal/PlainMonthDay/prototype/toLocaleString/branding': [FAIL],
   'built-ins/Temporal/PlainMonthDay/prototype/toPlainDate/argument-not-object': [FAIL],
   'built-ins/Temporal/PlainMonthDay/prototype/toPlainDate/branding': [FAIL],