Issue #2390 - Part 1: Base implementation of Intl.ListFormat.

js/src/builtin/intl/CommonFunctions.js

@@ -732,6 +732,7 @@ function initializeIntlObject(obj, type, lazyData) {
 
     assert((type === "Collator" && IsCollator(obj)) ||
            (type === "DateTimeFormat" && IsDateTimeFormat(obj)) ||
+           (type === "ListFormat" && IsListFormat(obj) !== null) ||
            (type === "NumberFormat" && IsNumberFormat(obj)) ||
            (type === "PluralRules" && IsPluralRules(obj)) ||
            (type === "RelativeTimeFormat" && IsRelativeTimeFormat(obj)),
@@ -815,6 +816,7 @@ function getIntlObjectInternals(obj) {
     assert(hasOwn("type", internals), "missing type");
     assert((internals.type === "Collator" && IsCollator(obj)) ||
            (internals.type === "DateTimeFormat" && IsDateTimeFormat(obj)) ||
+           (internals.type === "ListFormat" && IsListFormat(obj)) ||
            (internals.type === "NumberFormat" && IsNumberFormat(obj)) ||
            (internals.type === "PluralRules" && IsPluralRules(obj)) ||
            (internals.type === "RelativeTimeFormat" && IsRelativeTimeFormat(obj)),
@@ -850,6 +852,9 @@ function getInternals(obj) {
       case "DateTimeFormat":
         internalProps = resolveDateTimeFormatInternals(internals.lazyData);
         break;
+      case "ListFormat":
+        internalProps = resolveListFormatInternals(internals.lazyData);
+        break;
       case "PluralRules":
         internalProps = resolvePluralRulesInternals(internals.lazyData);
         break;

js/src/builtin/intl/IntlObject.cpp

@@ -22,6 +22,7 @@
 #include "builtin/intl/CommonFunctions.h"
 #include "builtin/intl/DateTimeFormat.h"
 #include "builtin/intl/LanguageTag.h"
+#include "builtin/intl/ListFormat.h"
 #include "builtin/intl/ICUHeader.h"
 #include "builtin/intl/Locale.h"
 #include "builtin/intl/NumberFormat.h"
@@ -523,6 +524,8 @@ js::intl_BestAvailableLocale(JSContext* cx, unsigned argc, Value* vp)
             kind = SupportedLocaleKind::Collator;
         } else if (StringEqualsAscii(typeStr, "DateTimeFormat")) {
             kind = SupportedLocaleKind::DateTimeFormat;
+        } else if (StringEqualsAscii(typeStr, "ListFormat")) {
+            kind = SupportedLocaleKind::ListFormat;
         } else if (StringEqualsAscii(typeStr, "NumberFormat")) {
             kind = SupportedLocaleKind::NumberFormat;
         } else if (StringEqualsAscii(typeStr, "PluralRules")) {
@@ -649,12 +652,12 @@ js::intl_supportedLocaleOrFallback(JSContext* cx, unsigned argc, Value* vp)
     // That implies we must ignore any candidate which isn't supported by all Intl
     // service constructors.
     //
-    // Note: We don't test the supported locales of either Intl.PluralRules or
-    // Intl.RelativeTimeFormat, because ICU doesn't provide the necessary API to
-    // return actual set of supported locales for these constructors. Instead it
-    // returns the complete set of available locales for ULocale, which is a
-    // superset of the locales supported by Collator, NumberFormat, and
-    // DateTimeFormat.
+    // Note: We don't test the supported locales of either Intl.ListFormat,
+    // Intl.PluralRules, Intl.RelativeTimeFormat, because ICU doesn't provide the
+    // necessary API to return actual set of supported locales for these
+    // constructors. Instead it returns the complete set of available locales for
+    // ULocale, which is a superset of the locales supported by Collator,
+    // NumberFormat, and DateTimeFormat.
     bool isSupported = true;
     for (auto kind : {SupportedLocaleKind::Collator, SupportedLocaleKind::DateTimeFormat,
                       SupportedLocaleKind::NumberFormat}) {

js/src/builtin/intl/ListFormat.cpp

@@ -0,0 +1,501 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * 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/. */
+
+#include "builtin/intl/ListFormat.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Casting.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/Unused.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "builtin/intl/CommonFunctions.h"
+#include "builtin/intl/ScopedICUObject.h"
+#include "js/Utility.h"
+#include "js/Vector.h"
+#include "unicode/uformattedvalue.h"
+#include "unicode/ulistformatter.h"
+#include "unicode/utypes.h"
+
+#include "jscntxt.h"
+#include "jsobjinlines.h"
+
+#include "vm/SelfHosting.h"
+#include "vm/NativeObject-inl.h"
+
+using namespace js;
+
+using mozilla::AssertedCast;
+
+using js::intl::CallICU;
+using js::intl::IcuLocale;
+
+const ClassOps ListFormatObject::classOps_ = {nullptr, /* addProperty */
+                                                nullptr, /* delProperty */
+                                                nullptr, /* getProperty */
+                                                nullptr, /* setProperty */
+                                                nullptr, /* enumerate */
+                                                nullptr, /* resolve */
+                                                nullptr, /* mayResolve */
+                                                ListFormatObject::finalize};
+const Class ListFormatObject::class_ = {
+    js_Object_str,
+    JSCLASS_HAS_RESERVED_SLOTS(ListFormatObject::SLOT_COUNT) |
+        JSCLASS_HAS_CACHED_PROTO(JSProto_ListFormat) |
+        JSCLASS_FOREGROUND_FINALIZE,
+    &ListFormatObject::classOps_
+};
+
+const Class& ListFormatObject::protoClass_ = PlainObject::class_;
+
+#if JS_HAS_TOSOURCE
+static bool
+listFormat_toSource(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setString(cx->names().ListFormat);
+  return true;
+}
+#endif
+
+static const JSFunctionSpec listFormat_static_methods[] = {
+    JS_SELF_HOSTED_FN("supportedLocalesOf",
+                      "Intl_ListFormat_supportedLocalesOf", 1, 0),
+    JS_FS_END};
+
+static const JSFunctionSpec listFormat_methods[] = {
+    JS_SELF_HOSTED_FN("resolvedOptions", "Intl_ListFormat_resolvedOptions", 0,
+                      0),
+    JS_SELF_HOSTED_FN("format", "Intl_ListFormat_format", 1, 0),
+#ifndef U_HIDE_DRAFT_API
+    JS_SELF_HOSTED_FN("formatToParts", "Intl_ListFormat_formatToParts", 1, 0),
+#endif
+#if JS_HAS_TOSOURCE
+    JS_FN(js_toSource_str, listFormat_toSource, 0, 0),
+#endif
+    JS_FS_END
+};
+    
+
+static const JSPropertySpec listFormat_properties[] = {
+    JS_STRING_SYM_PS(toStringTag, "Intl.ListFormat", JSPROP_READONLY),
+    JS_PS_END};
+
+static JSObject*
+CreateListFormatPrototype(JSContext* cx, JSProtoKey key) {
+  return GlobalObject::createBlankPrototype<PlainObject>(cx, cx->global());
+}
+
+static bool ListFormat(JSContext* cx, unsigned argc, Value* vp);
+
+const ClassSpec ListFormatObject::classSpec_ = {
+    GenericCreateConstructor<ListFormat, 0, gc::AllocKind::FUNCTION>,
+    CreateListFormatPrototype,
+    listFormat_static_methods,
+    nullptr,
+    listFormat_methods,
+    listFormat_properties
+//    nullptr,
+//    ClassSpec::DontDefineConstructor
+};
+
+/**
+ * Intl.ListFormat([ locales [, options]])
+ */
+static bool ListFormat(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+
+  // Step 1.
+  if (!ThrowIfNotConstructing(cx, args, "Intl.ListFormat")) {
+    return false;
+  }
+
+  // Step 2 (Inlined 9.1.14, OrdinaryCreateFromConstructor).
+  RootedObject proto(cx);
+  if (!GetPrototypeFromCallableConstructor(cx, args, &proto)) {
+    return false;
+  }
+
+  Rooted<ListFormatObject*> listFormat(
+      cx, NewObjectWithClassProto<ListFormatObject>(cx, proto));
+  if (!listFormat) {
+    return false;
+  }
+
+  HandleValue locales = args.get(0);
+  HandleValue options = args.get(1);
+
+  // Step 3.
+  if (!intl::InitializeObject(cx, listFormat, cx->names().InitializeListFormat,
+                              locales, options)) {
+    return false;
+  }
+
+  args.rval().setObject(*listFormat);
+  return true;
+}
+
+void js::ListFormatObject::finalize(FreeOp* fop, JSObject* obj) {
+  MOZ_ASSERT(fop->onMainThread());
+
+  if (UListFormatter* lf = obj->as<ListFormatObject>().getListFormatter()) {
+    ulistfmt_close(lf);
+  }
+}
+
+bool js::AddListFormatConstructor(JSContext* cx, JS::Handle<JSObject*> intl) {
+  JSObject* ctor = GlobalObject::createConstructor(cx, ListFormat, cx->names().ListFormat, 0);
+  if (!ctor) {
+    return false;
+  }
+
+  RootedValue ctorValue(cx, ObjectValue(*ctor));
+  return DefineProperty(cx, intl, cx->names().ListFormat, ctorValue, 0);
+}
+
+/**
+ * Returns a new UListFormatter with the locale and list formatting options
+ * of the given ListFormat.
+ */
+static UListFormatter* NewUListFormatter(JSContext* cx,
+                                         Handle<ListFormatObject*> listFormat) {
+  RootedObject internals(cx, intl::GetInternalsObject(cx, listFormat));
+  if (!internals) {
+    return nullptr;
+  }
+
+  RootedValue value(cx);
+
+  if (!GetProperty(cx, internals, internals, cx->names().locale, &value)) {
+    return nullptr;
+  }
+  JSAutoByteString bytes;
+  char* locale = bytes.encodeLatin1(cx, value.toString());
+  if (!locale) {
+    return nullptr;
+  }
+
+  enum class ListFormatType { Conjunction, Disjunction, Unit };
+
+  ListFormatType type;
+  if (!GetProperty(cx, internals, internals, cx->names().type, &value)) {
+    return nullptr;
+  }
+  {
+    JSLinearString* strType = value.toString()->ensureLinear(cx);
+    if (!strType) {
+      return nullptr;
+    }
+
+    if (StringEqualsAscii(strType, "conjunction")) {
+      type = ListFormatType::Conjunction;
+    } else if (StringEqualsAscii(strType, "disjunction")) {
+      type = ListFormatType::Disjunction;
+    } else {
+      MOZ_ASSERT(StringEqualsAscii(strType, "unit"));
+      type = ListFormatType::Unit;
+    }
+  }
+
+  enum class ListFormatStyle { Long, Short, Narrow };
+
+  ListFormatStyle style;
+  if (!GetProperty(cx, internals, internals, cx->names().style, &value)) {
+    return nullptr;
+  }
+  {
+    JSLinearString* strStyle = value.toString()->ensureLinear(cx);
+    if (!strStyle) {
+      return nullptr;
+    }
+
+    if (StringEqualsAscii(strStyle, "long")) {
+      style = ListFormatStyle::Long;
+    } else if (StringEqualsAscii(strStyle, "short")) {
+      style = ListFormatStyle::Short;
+    } else {
+      MOZ_ASSERT(StringEqualsAscii(strStyle, "narrow"));
+      style = ListFormatStyle::Narrow;
+    }
+  }
+
+  // We're currently only supporting "conjunctive-long" list formatters due to
+  // missing ICU APIs: https://unicode-org.atlassian.net/browse/ICU-12863
+  MOZ_ASSERT(type == ListFormatType::Conjunction);
+  MOZ_ASSERT(style == ListFormatStyle::Long);
+
+  mozilla::Unused << type;
+  mozilla::Unused << style;
+
+  UErrorCode status = U_ZERO_ERROR;
+  UListFormatter* lf = ulistfmt_open(IcuLocale(locale), &status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return nullptr;
+  }
+  return lf;
+}
+
+static constexpr size_t DEFAULT_LIST_LENGTH = 8;
+
+using ListFormatStringVector = Vector<UniqueTwoByteChars, DEFAULT_LIST_LENGTH>;
+using ListFormatStringLengthVector = Vector<int32_t, DEFAULT_LIST_LENGTH>;
+
+static_assert(sizeof(UniqueTwoByteChars) == sizeof(char16_t*),
+              "UniqueTwoByteChars are stored efficiently and are held in "
+              "continuous memory");
+
+/**
+ * FormatList ( listFormat, list )
+ */
+static bool FormatList(JSContext* cx, UListFormatter* lf,
+                       const ListFormatStringVector& strings,
+                       const ListFormatStringLengthVector& stringLengths,
+                       MutableHandleValue result) {
+  MOZ_ASSERT(strings.length() == stringLengths.length());
+  MOZ_ASSERT(strings.length() <= INT32_MAX);
+
+  JSString* str = intl::CallICU(cx, [lf, &strings, &stringLengths](
+                                        UChar* chars, int32_t size,
+                                        UErrorCode* status) {
+    return ulistfmt_format(
+        lf, reinterpret_cast<char16_t* const*>(strings.begin()),
+        stringLengths.begin(), int32_t(strings.length()), chars, size, status);
+  });
+  if (!str) {
+    return false;
+  }
+
+  result.setString(str);
+  return true;
+}
+
+#ifndef U_HIDE_DRAFT_API
+static JSString* FormattedValueToString(JSContext* cx,
+                                        const UFormattedValue* formattedValue) {
+  UErrorCode status = U_ZERO_ERROR;
+  int32_t strLength;
+  const char16_t* str = ufmtval_getString(formattedValue, &strLength, &status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return nullptr;
+  }
+
+  return NewStringCopyN<CanGC>(cx, str, AssertedCast<uint32_t>(strLength));
+}
+
+/**
+ * FormatListToParts ( listFormat, list )
+ */
+static bool FormatListToParts(JSContext* cx, UListFormatter* lf,
+                              const ListFormatStringVector& strings,
+                              const ListFormatStringLengthVector& stringLengths,
+                              MutableHandleValue result) {
+  MOZ_ASSERT(strings.length() == stringLengths.length());
+  MOZ_ASSERT(strings.length() <= INT32_MAX);
+
+  UErrorCode status = U_ZERO_ERROR;
+  UFormattedList* formatted = ulistfmt_openResult(&status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return false;
+  }
+  ScopedICUObject<UFormattedList, ulistfmt_closeResult> toClose(formatted);
+
+  ulistfmt_formatStringsToResult(
+      lf, reinterpret_cast<char16_t* const*>(strings.begin()),
+      stringLengths.begin(), int32_t(strings.length()), formatted, &status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return false;
+  }
+
+  const UFormattedValue* formattedValue =
+      ulistfmt_resultAsValue(formatted, &status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return false;
+  }
+
+  RootedString overallResult(cx, FormattedValueToString(cx, formattedValue));
+  if (!overallResult) {
+    return false;
+  }
+
+  RootedArrayObject partsArray(cx, NewDenseEmptyArray(cx));
+  if (!partsArray) {
+    return false;
+  }
+
+  using FieldType = js::ImmutablePropertyNamePtr JSAtomState::*;
+
+  size_t lastEndIndex = 0;
+  RootedObject singlePart(cx);
+  RootedValue partType(cx);
+  RootedValue val(cx);
+
+  auto AppendPart = [&](FieldType type, size_t beginIndex, size_t endIndex) {
+    singlePart = NewBuiltinClassInstance<PlainObject>(cx);
+    if (!singlePart) {
+      return false;
+    }
+
+    partType = StringValue(cx->names().*type);
+    if (!DefineProperty(cx, singlePart, cx->names().type, partType)) {
+      return false;
+    }
+
+    JSLinearString* partSubstr = NewDependentString(
+        cx, overallResult, beginIndex, endIndex - beginIndex);
+    if (!partSubstr) {
+      return false;
+    }
+
+    val = StringValue(partSubstr);
+    if (!DefineProperty(cx, singlePart, cx->names().value, val)) {
+      return false;
+    }
+
+    if (!NewbornArrayPush(cx, partsArray, ObjectValue(*singlePart))) {
+      return false;
+    }
+
+    lastEndIndex = endIndex;
+    return true;
+  };
+
+  UConstrainedFieldPosition* fpos = ucfpos_open(&status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return false;
+  }
+  ScopedICUObject<UConstrainedFieldPosition, ucfpos_close> toCloseFpos(fpos);
+
+  // We're only interested in ULISTFMT_ELEMENT_FIELD fields.
+  ucfpos_constrainField(fpos, UFIELD_CATEGORY_LIST, ULISTFMT_ELEMENT_FIELD,
+                        &status);
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return false;
+  }
+
+  while (true) {
+    bool hasMore = ufmtval_nextPosition(formattedValue, fpos, &status);
+    if (U_FAILURE(status)) {
+      intl::ReportInternalError(cx);
+      return false;
+    }
+    if (!hasMore) {
+      break;
+    }
+
+    int32_t beginIndexInt, endIndexInt;
+    ucfpos_getIndexes(fpos, &beginIndexInt, &endIndexInt, &status);
+    if (U_FAILURE(status)) {
+      intl::ReportInternalError(cx);
+      return false;
+    }
+
+    MOZ_ASSERT(beginIndexInt >= 0);
+    MOZ_ASSERT(endIndexInt >= 0);
+    MOZ_ASSERT(beginIndexInt <= endIndexInt,
+               "field iterator returning invalid range");
+
+    size_t beginIndex = size_t(beginIndexInt);
+    size_t endIndex = size_t(endIndexInt);
+
+    // Indices are guaranteed to be returned in order (from left to right).
+    MOZ_ASSERT(lastEndIndex <= beginIndex,
+               "field iteration didn't return fields in order start to "
+               "finish as expected");
+
+    if (lastEndIndex < beginIndex) {
+      if (!AppendPart(&JSAtomState::literal, lastEndIndex, beginIndex)) {
+        return false;
+      }
+    }
+
+    if (!AppendPart(&JSAtomState::element, beginIndex, endIndex)) {
+      return false;
+    }
+  }
+
+  // Append any final literal.
+  if (lastEndIndex < overallResult->length()) {
+    if (!AppendPart(&JSAtomState::literal, lastEndIndex,
+                    overallResult->length())) {
+      return false;
+    }
+  }
+
+  result.setObject(*partsArray);
+  return true;
+}
+#endif  // U_HIDE_DRAFT_API
+
+bool js::intl_FormatList(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  MOZ_ASSERT(args.length() == 3);
+
+  Rooted<ListFormatObject*> listFormat(
+      cx, &args[0].toObject().as<ListFormatObject>());
+
+  bool formatToParts = args[2].toBoolean();
+
+  // Obtain a cached UListFormatter object.
+  UListFormatter* lf = listFormat->getListFormatter();
+  if (!lf) {
+    lf = NewUListFormatter(cx, listFormat);
+    if (!lf) {
+      return false;
+    }
+    listFormat->setListFormatter(lf);
+  }
+
+  // Collect all strings and their lengths.
+  ListFormatStringVector strings(cx);
+  ListFormatStringLengthVector stringLengths(cx);
+
+  RootedArrayObject list(cx, &args[1].toObject().as<ArrayObject>());
+  RootedValue value(cx);
+  for (uint32_t i = 0; i < list->length(); i++) {
+    if (!GetElement(cx, list, list, i, &value)) {
+      return false;
+    }
+
+    JSLinearString* linear = value.toString()->ensureLinear(cx);
+    if (!linear) {
+      return false;
+    }
+
+    size_t linearLength = linear->length();
+    if (!stringLengths.append(linearLength)) {
+      return false;
+    }
+
+    UniqueTwoByteChars chars = cx->make_pod_array<char16_t>(linearLength);
+    if (!chars) {
+      return false;
+    }
+    CopyChars(chars.get(), *linear);
+
+    if (!strings.append(std::move(chars))) {
+      return false;
+    }
+  }
+
+  // Use the UListFormatter to actually format the strings.
+#ifndef U_HIDE_DRAFT_API
+  if (formatToParts) {
+    return FormatListToParts(cx, lf, strings, stringLengths, args.rval());
+  }
+#else
+  MOZ_ASSERT(!formatToParts);
+#endif
+
+  return FormatList(cx, lf, strings, stringLengths, args.rval());
+}

js/src/builtin/intl/ListFormat.h

@@ -0,0 +1,67 @@
+/* -*- 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/. */
+
+#ifndef builtin_intl_ListFormat_h
+#define builtin_intl_ListFormat_h
+
+#include "mozilla/Attributes.h"
+
+#include <stdint.h>
+
+#include "builtin/intl/CommonFunctions.h"
+#include "builtin/SelfHostingDefines.h"
+#include "js/Class.h"
+#include "js/RootingAPI.h"
+#include "vm/NativeObject.h"
+
+struct UListFormatter;
+
+namespace js {
+
+class ListFormatObject : public NativeObject {
+ public:
+  static const Class class_;
+  static const Class& protoClass_;
+
+  static constexpr uint32_t INTERNALS_SLOT = 0;
+  static constexpr uint32_t ULIST_FORMATTER_SLOT = 1;
+  static constexpr uint32_t SLOT_COUNT = 2;
+
+  static_assert(INTERNALS_SLOT == INTL_INTERNALS_OBJECT_SLOT,
+                "INTERNALS_SLOT must match self-hosting define for internals "
+                "object slot");
+
+  UListFormatter* getListFormatter() const {
+    const auto& slot = getFixedSlot(ULIST_FORMATTER_SLOT);
+    if (slot.isUndefined()) {
+      return nullptr;
+    }
+    return static_cast<UListFormatter*>(slot.toPrivate());
+  }
+
+  void setListFormatter(UListFormatter* formatter) {
+    setFixedSlot(ULIST_FORMATTER_SLOT, PrivateValue(formatter));
+  }
+
+ private:
+  static const ClassOps classOps_;
+  static const ClassSpec classSpec_;
+
+  static void finalize(FreeOp* fop, JSObject* obj);
+};
+
+/**
+ * Returns a string representing the array of string values |list| according to
+ * the effective locale and the formatting options of the given ListFormat.
+ *
+ * Usage: formatted = intl_FormatList(listFormat, list, formatToParts)
+ */
+extern bool intl_FormatList(JSContext* cx, unsigned argc,
+                                         Value* vp);
+
+}  // namespace js
+
+#endif /* builtin_intl_ListFormat_h */

js/src/builtin/intl/ListFormat.js

@@ -0,0 +1,262 @@
+/* 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/. */
+
+/**
+ * ListFormat internal properties.
+ */
+var listFormatInternalProperties = {
+    localeData: function() // eslint-disable-line object-shorthand
+    {
+        // ListFormat don't support any extension keys.
+        return {};
+    },
+    relevantExtensionKeys: []
+};
+
+/**
+ * Intl.ListFormat ( [ locales [ , options ] ] )
+ *
+ * Compute an internal properties object from |lazyListFormatData|.
+ */
+function resolveListFormatInternals(lazyListFormatData) {
+    assert(IsObject(lazyListFormatData), "lazy data not an object?");
+
+    var internalProps = std_Object_create(null);
+
+    var ListFormat = listFormatInternalProperties;
+
+    // Compute effective locale.
+
+    // Step 9.
+    var localeData = ListFormat.localeData;
+
+    // Step 10.
+    var r = ResolveLocale("ListFormat",
+                          lazyListFormatData.requestedLocales,
+                          lazyListFormatData.opt,
+                          ListFormat.relevantExtensionKeys,
+                          localeData);
+
+    // Step 11.
+    internalProps.locale = r.locale;
+
+    // Step 13.
+    internalProps.type = lazyListFormatData.type;
+
+    // Step 15.
+    internalProps.style = lazyListFormatData.style;
+
+    // Steps 16-23 (not applicable in our implementation).
+
+    // The caller is responsible for associating |internalProps| with the right
+    // object using |setInternalProperties|.
+    return internalProps;
+}
+
+/**
+ * Returns an object containing the ListFormat internal properties of |obj|.
+ */
+function getListFormatInternals(obj) {
+    assert(IsObject(obj), "getListFormatInternals called with non-object");
+    assert(GuardToListFormat(obj) !== null, "getListFormatInternals called with non-ListFormat");
+
+    var internals = getIntlObjectInternals(obj);
+    assert(internals.type === "ListFormat", "bad type escaped getIntlObjectInternals");
+
+    // If internal properties have already been computed, use them.
+    var internalProps = maybeInternalProperties(internals);
+    if (internalProps)
+        return internalProps;
+
+    // Otherwise it's time to fully create them.
+    internalProps = resolveListFormatInternals(internals.lazyData);
+    setInternalProperties(internals, internalProps);
+    return internalProps;
+}
+
+/**
+ * Intl.ListFormat ( [ locales [ , options ] ] )
+ *
+ * Initializes an object as a ListFormat.
+ *
+ * This method is complicated a moderate bit by its implementing initialization
+ * as a *lazy* concept.  Everything that must happen now, does -- but we defer
+ * all the work we can until the object is actually used as a ListFormat.
+ * This later work occurs in |resolveListFormatInternals|; steps not noted
+ * here occur there.
+ */
+function InitializeListFormat(listFormat, locales, options) {
+    assert(IsObject(listFormat), "InitializeListFormat called with non-object");
+    assert(GuardToListFormat(listFormat) !== null, "InitializeListFormat called with non-ListFormat");
+
+    // Lazy ListFormat data has the following structure:
+    //
+    //   {
+    //     requestedLocales: List of locales,
+    //     type: "conjunction" / "disjunction" / "unit",
+    //     style: "long" / "short" / "narrow",
+    //
+    //     opt: // opt object computed in InitializeListFormat
+    //       {
+    //         localeMatcher: "lookup" / "best fit",
+    //       }
+    //   }
+    //
+    // Note that lazy data is only installed as a final step of initialization,
+    // so every ListFormat lazy data object has *all* these properties, never a
+    // subset of them.
+    var lazyListFormatData = std_Object_create(null);
+
+    // Step 3.
+    var requestedLocales = CanonicalizeLocaleList(locales);
+    lazyListFormatData.requestedLocales = requestedLocales;
+
+    // Steps 4-5.
+    if (options === undefined)
+        options = std_Object_create(null);
+    else
+        options = ToObject(options);
+
+    // Step 6.
+    var opt = new Record();
+    lazyListFormatData.opt = opt;
+
+    // Steps 7-8.
+    let matcher = GetOption(options, "localeMatcher", "string", ["lookup", "best fit"], "best fit");
+    opt.localeMatcher = matcher;
+
+    // Compute formatting options.
+
+    // We're currently only supporting "conjunctive-long" list formatters due to
+    // missing ICU APIs: https://unicode-org.atlassian.net/browse/ICU-12863
+
+    // Steps 12-13.
+    var type = GetOption(options, "type", "string", ["conjunction"], "conjunction");
+    lazyListFormatData.type = type;
+
+    // Steps 14-15.
+    var style = GetOption(options, "style", "string", ["long"], "long");
+    lazyListFormatData.style = style;
+
+    // We've done everything that must be done now: mark the lazy data as fully
+    // computed and install it.
+    initializeIntlObject(listFormat, "ListFormat", lazyListFormatData);
+}
+
+/**
+ * Returns the subset of the given locale list for which this locale list has a
+ * matching (possibly fallback) locale. Locales appear in the same order in the
+ * returned list as in the input list.
+ */
+function Intl_ListFormat_supportedLocalesOf(locales /*, options*/) {
+    var options = arguments.length > 1 ? arguments[1] : undefined;
+
+    // Step 1.
+    var availableLocales = "ListFormat";
+
+    // Step 2.
+    var requestedLocales = CanonicalizeLocaleList(locales);
+
+    // Step 3.
+    return SupportedLocales(availableLocales, requestedLocales, options);
+}
+
+/**
+ * StringListFromIterable ( iterable )
+ */
+function StringListFromIterable(iterable, methodName) {
+    // Step 1.
+    if (iterable === undefined) {
+        return [];
+    }
+
+    // Step 3.
+    var list = [];
+
+    // Steps 2, 4-5.
+    for (var element of allowContentIter(iterable)) {
+        // Step 5.b.ii.
+        if (typeof element !== "string") {
+            ThrowTypeError(JSMSG_NOT_EXPECTED_TYPE, methodName, "string", typeof element);
+        }
+
+        // Step 5.b.iii.
+        _DefineDataProperty(list, list.length, element);
+    }
+
+    // Step 6.
+    return list;
+}
+
+/**
+ * Intl.ListFormat.prototype.format ( list )
+ */
+function Intl_ListFormat_format(list) {
+    // Step 1.
+    var listFormat = this;
+
+    // Steps 2-3.
+    if (!IsObject(listFormat) || (listFormat = GuardToListFormat(listFormat)) === null) {
+        return callFunction(CallListFormatMethodIfWrapped, this, list,
+                            "Intl_ListFormat_format");
+    }
+
+    // Ensure the ListFormat internals are resolved.
+    getListFormatInternals(listFormat);
+
+    // Step 4.
+    var stringList = StringListFromIterable(list, "format");
+
+    // Step 5.
+    return intl_FormatList(listFormat, stringList, /* formatToParts = */ false);
+}
+
+/**
+ * Intl.ListFormat.prototype.formatToParts ( list )
+ */
+function Intl_ListFormat_formatToParts(list) {
+    // Step 1.
+    var listFormat = this;
+
+    // Steps 2-3.
+    if (!IsObject(listFormat) || (listFormat = GuardToListFormat(listFormat)) === null) {
+        return callFunction(CallListFormatMethodIfWrapped, this, list,
+                            "Intl_ListFormat_formatToParts");
+    }
+
+    // Ensure the ListFormat internals are resolved.
+    getListFormatInternals(listFormat);
+
+    // Step 4.
+    var stringList = StringListFromIterable(list, "formatToParts");
+
+    // Step 5.
+    return intl_FormatList(listFormat, stringList, /* formatToParts = */ true);
+}
+
+/**
+ * Returns the resolved options for a ListFormat object.
+ */
+function Intl_ListFormat_resolvedOptions() {
+    // Step 1.
+    var listFormat = this;
+
+    // Steps 2-3.
+    if (!IsObject(listFormat) || (listFormat = GuardToListFormat(listFormat)) === null) {
+        return callFunction(CallListFormatMethodIfWrapped, this,
+                            "Intl_ListFormat_resolvedOptions");
+    }
+
+    var internals = getListFormatInternals(listFormat);
+
+    // Steps 4-5.
+    var result = {
+        locale: internals.locale,
+        type: internals.type,
+        style: internals.style,
+    };
+
+    // Step 6.
+    return result;
+}

js/src/builtin/intl/SharedIntlData.h

@@ -1,285 +1,286 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
- * 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/. */
-
-#ifndef builtin_intl_SharedIntlData_h
-#define builtin_intl_SharedIntlData_h
-
-#include "mozilla/MemoryReporting.h"
-
-#include <stddef.h>
-
-#include "jsalloc.h"
-#include "js/CharacterEncoding.h"
-#include "js/GCAPI.h"
-#include "js/GCHashTable.h"
-#include "js/RootingAPI.h"
-#include "js/Utility.h"
-#include "vm/String.h"
-
-namespace js {
-
-namespace intl {
-
-/**
- * Stores Intl data which can be shared across compartments (but not contexts).
- *
- * Used for data which is expensive when computed repeatedly or is not
- * available through ICU.
- */
-class SharedIntlData
-{
-    struct LinearStringLookup
-    {
-        union {
-            const JS::Latin1Char* latin1Chars;
-            const char16_t* twoByteChars;
-        };
-        bool isLatin1;
-        size_t length;
-        JS::AutoCheckCannotGC nogc;
-        HashNumber hash = 0;
-
-        explicit LinearStringLookup(JSLinearString* string)
-          : isLatin1(string->hasLatin1Chars()), length(string->length())
-        {
-            if (isLatin1)
-                latin1Chars = string->latin1Chars(nogc);
-            else
-                twoByteChars = string->twoByteChars(nogc);
-        }
-
-        LinearStringLookup(const char* chars, size_t length)
-          : isLatin1(true), length(length)
-        {
-            latin1Chars = reinterpret_cast<const JS::Latin1Char*>(chars);
-        }
-    };
-
-  private:
-    /**
-     * Information tracking the set of the supported time zone names, derived
-     * from the IANA time zone database <https://www.iana.org/time-zones>.
-     *
-     * There are two kinds of IANA time zone names: Zone and Link (denoted as
-     * such in database source files). Zone names are the canonical, preferred
-     * name for a time zone, e.g. Asia/Kolkata. Link names simply refer to
-     * target Zone names for their meaning, e.g. Asia/Calcutta targets
-     * Asia/Kolkata. That a name is a Link doesn't *necessarily* reflect a
-     * sense of deprecation: some Link names also exist partly for convenience,
-     * e.g. UTC and GMT as Link names targeting the Zone name Etc/UTC.
-     *
-     * Two data sources determine the time zone names we support: those ICU
-     * supports and IANA's zone information.
-     *
-     * Unfortunately the names ICU and IANA support, and their Link
-     * relationships from name to target, aren't identical, so we can't simply
-     * implicitly trust ICU's name handling. We must perform various
-     * preprocessing of user-provided zone names and post-processing of
-     * ICU-provided zone names to implement ECMA-402's IANA-consistent behavior.
-     *
-     * Also see <https://ssl.icu-project.org/trac/ticket/12044> and
-     * <http://unicode.org/cldr/trac/ticket/9892>.
-     */
-
-    using TimeZoneName = JSAtom*;
-
-    struct TimeZoneHasher
-    {
-        struct Lookup : LinearStringLookup
-        {
-            explicit Lookup(JSFlatString* timeZone);
-        };
-
-        static js::HashNumber hash(const Lookup& lookup) { return lookup.hash; }
-        static bool match(TimeZoneName key, const Lookup& lookup);
-    };
-
-    using TimeZoneSet = js::GCHashSet<TimeZoneName,
-                                      TimeZoneHasher,
-                                      js::SystemAllocPolicy>;
-
-    using TimeZoneMap = js::GCHashMap<TimeZoneName,
-                                      TimeZoneName,
-                                      TimeZoneHasher,
-                                      js::SystemAllocPolicy>;
-
-    /**
-     * As a threshold matter, available time zones are those time zones ICU
-     * supports, via ucal_openTimeZones. But ICU supports additional non-IANA
-     * time zones described in intl/icu/source/tools/tzcode/icuzones (listed in
-     * IntlTimeZoneData.cpp's |legacyICUTimeZones|) for its own backwards
-     * compatibility purposes. This set consists of ICU's supported time zones,
-     * minus all backwards-compatibility time zones.
-     */
-    TimeZoneSet availableTimeZones;
-
-    /**
-     * IANA treats some time zone names as Zones, that ICU instead treats as
-     * Links. For example, IANA considers "America/Indiana/Indianapolis" to be
-     * a Zone and "America/Fort_Wayne" a Link that targets it, but ICU
-     * considers the former a Link that targets "America/Indianapolis" (which
-     * IANA treats as a Link).
-     *
-     * ECMA-402 requires that we respect IANA data, so if we're asked to
-     * canonicalize a time zone name in this set, we must *not* return ICU's
-     * canonicalization.
-     */
-    TimeZoneSet ianaZonesTreatedAsLinksByICU;
-
-    /**
-     * IANA treats some time zone names as Links to one target, that ICU
-     * instead treats as either Zones, or Links to different targets. An
-     * example of the former is "Asia/Calcutta, which IANA assigns the target
-     * "Asia/Kolkata" but ICU considers its own Zone. An example of the latter
-     * is "America/Virgin", which IANA assigns the target
-     * "America/Port_of_Spain" but ICU assigns the target "America/St_Thomas".
-     *
-     * ECMA-402 requires that we respect IANA data, so if we're asked to
-     * canonicalize a time zone name that's a key in this map, we *must* return
-     * the corresponding value and *must not* return ICU's canonicalization.
-     */
-    TimeZoneMap ianaLinksCanonicalizedDifferentlyByICU;
-
-    bool timeZoneDataInitialized = false;
-
-    /**
-     * Precomputes the available time zone names, because it's too expensive to
-     * call ucal_openTimeZones() repeatedly.
-     */
-    bool ensureTimeZones(JSContext* cx);
-
-  public:
-    /**
-     * Returns the validated time zone name in |result|. If the input time zone
-     * isn't a valid IANA time zone name, |result| remains unchanged.
-     */
-    bool validateTimeZoneName(JSContext* cx, JS::HandleString timeZone,
-                              JS::MutableHandleString result);
-
-    /**
-     * Returns the canonical time zone name in |result|. If no canonical name
-     * was found, |result| remains unchanged.
-     *
-     * This method only handles time zones which are canonicalized differently
-     * by ICU when compared to IANA.
-     */
-    bool tryCanonicalizeTimeZoneConsistentWithIANA(JSContext* cx, JS::HandleString timeZone,
-                                                   JS::MutableHandleString result);
-  private:
-    using Locale = JSAtom*;
-
-    struct LocaleHasher
-    {
-        struct Lookup : LinearStringLookup
-        {
-            explicit Lookup(JSLinearString* locale);
-            Lookup(const char* chars, size_t length);
-        };
-
-        static js::HashNumber hash(const Lookup& lookup) { return lookup.hash; }
-        static bool match(Locale key, const Lookup& lookup);
-    };
-
-    using LocaleSet = GCHashSet<Locale, LocaleHasher, SystemAllocPolicy>;
-
-    // Set of supported locales for all Intl service constructors except Collator,
-    // which uses its own set.
-    //
-    // UDateFormat:
-    // udat_[count,get]Available() return the same results as their
-    // uloc_[count,get]Available() counterparts.
-    //
-    // UNumberFormatter:
-    // unum_[count,get]Available() return the same results as their
-    // uloc_[count,get]Available() counterparts.
-    //
-    // UPluralRules and URelativeDateTimeFormatter:
-    // We're going to use ULocale availableLocales as per ICU recommendation:
-    // https://unicode-org.atlassian.net/browse/ICU-12756
-    LocaleSet supportedLocales;
-
-    // ucol_[count,get]Available() return different results compared to
-    // uloc_[count,get]Available(), we can't use |supportedLocales| here.
-    LocaleSet collatorSupportedLocales;
-
-    bool supportedLocalesInitialized = false;
-
-    // CountAvailable and GetAvailable describe the signatures used for ICU API
-    // to determine available locales for various functionality.
-    using CountAvailable = int32_t (*)();
-    using GetAvailable = const char* (*)(int32_t localeIndex);
-
-    static bool getAvailableLocales(JSContext* cx, LocaleSet& locales,
-                                    CountAvailable countAvailable,
-                                    GetAvailable getAvailable);
-
-    /**
-    * Precomputes the available locales sets.
-    */
-    bool ensureSupportedLocales(JSContext* cx);
-
-  public:
-    enum class SupportedLocaleKind {
-        Collator,
-        DateTimeFormat,
-        NumberFormat,
-        PluralRules,
-        RelativeTimeFormat
-    };
-
-    /**
-    * Sets |supported| to true if |locale| is supported by the requested Intl
-    * service constructor. Otherwise sets |supported| to false.
-    */
-    [[nodiscard]] bool isSupportedLocale(JSContext* cx, SupportedLocaleKind kind,
-                                         JS::Handle<JSString*> locale,
-                                         bool* supported);
-
-  private:
-    /**
-     * The case first parameter (BCP47 key "kf") allows to switch the order of
-     * upper- and lower-case characters. ICU doesn't directly provide an API
-     * to query the default case first value of a given locale, but instead
-     * requires to instantiate a collator object and then query the case first
-     * attribute (UCOL_CASE_FIRST).
-     * To avoid instantiating an additional collator object whenever we need
-     * to retrieve the default case first value of a specific locale, we
-     * compute the default case first value for every supported locale only
-     * once and then keep a list of all locales which don't use the default
-     * case first setting.
-     * There is almost no difference between lower-case first and when case
-     * first is disabled (UCOL_LOWER_FIRST resp. UCOL_OFF), so we only need to
-     * track locales which use upper-case first as their default setting.
-     */
-
-    LocaleSet upperCaseFirstLocales;
-
-    bool upperCaseFirstInitialized = false;
-
-    /**
-     * Precomputes the available locales which use upper-case first sorting.
-     */
-    bool ensureUpperCaseFirstLocales(JSContext* cx);
-
-  public:
-    /**
-     * Sets |isUpperFirst| to true if |locale| sorts upper-case characters
-     * before lower-case characters.
-     */
-    bool isUpperCaseFirst(JSContext* cx, JS::HandleString locale, bool* isUpperFirst);
-
-  public:
-    void destroyInstance();
-
-    void trace(JSTracer* trc);
-
-    size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
-};
-
-} // namespace intl
-
-} // namespace js
-
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * 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/. */
+
+#ifndef builtin_intl_SharedIntlData_h
+#define builtin_intl_SharedIntlData_h
+
+#include "mozilla/MemoryReporting.h"
+
+#include <stddef.h>
+
+#include "jsalloc.h"
+#include "js/CharacterEncoding.h"
+#include "js/GCAPI.h"
+#include "js/GCHashTable.h"
+#include "js/RootingAPI.h"
+#include "js/Utility.h"
+#include "vm/String.h"
+
+namespace js {
+
+namespace intl {
+
+/**
+ * Stores Intl data which can be shared across compartments (but not contexts).
+ *
+ * Used for data which is expensive when computed repeatedly or is not
+ * available through ICU.
+ */
+class SharedIntlData
+{
+    struct LinearStringLookup
+    {
+        union {
+            const JS::Latin1Char* latin1Chars;
+            const char16_t* twoByteChars;
+        };
+        bool isLatin1;
+        size_t length;
+        JS::AutoCheckCannotGC nogc;
+        HashNumber hash = 0;
+
+        explicit LinearStringLookup(JSLinearString* string)
+          : isLatin1(string->hasLatin1Chars()), length(string->length())
+        {
+            if (isLatin1)
+                latin1Chars = string->latin1Chars(nogc);
+            else
+                twoByteChars = string->twoByteChars(nogc);
+        }
+
+        LinearStringLookup(const char* chars, size_t length)
+          : isLatin1(true), length(length)
+        {
+            latin1Chars = reinterpret_cast<const JS::Latin1Char*>(chars);
+        }
+    };
+
+  private:
+    /**
+     * Information tracking the set of the supported time zone names, derived
+     * from the IANA time zone database <https://www.iana.org/time-zones>.
+     *
+     * There are two kinds of IANA time zone names: Zone and Link (denoted as
+     * such in database source files). Zone names are the canonical, preferred
+     * name for a time zone, e.g. Asia/Kolkata. Link names simply refer to
+     * target Zone names for their meaning, e.g. Asia/Calcutta targets
+     * Asia/Kolkata. That a name is a Link doesn't *necessarily* reflect a
+     * sense of deprecation: some Link names also exist partly for convenience,
+     * e.g. UTC and GMT as Link names targeting the Zone name Etc/UTC.
+     *
+     * Two data sources determine the time zone names we support: those ICU
+     * supports and IANA's zone information.
+     *
+     * Unfortunately the names ICU and IANA support, and their Link
+     * relationships from name to target, aren't identical, so we can't simply
+     * implicitly trust ICU's name handling. We must perform various
+     * preprocessing of user-provided zone names and post-processing of
+     * ICU-provided zone names to implement ECMA-402's IANA-consistent behavior.
+     *
+     * Also see <https://ssl.icu-project.org/trac/ticket/12044> and
+     * <http://unicode.org/cldr/trac/ticket/9892>.
+     */
+
+    using TimeZoneName = JSAtom*;
+
+    struct TimeZoneHasher
+    {
+        struct Lookup : LinearStringLookup
+        {
+            explicit Lookup(JSFlatString* timeZone);
+        };
+
+        static js::HashNumber hash(const Lookup& lookup) { return lookup.hash; }
+        static bool match(TimeZoneName key, const Lookup& lookup);
+    };
+
+    using TimeZoneSet = js::GCHashSet<TimeZoneName,
+                                      TimeZoneHasher,
+                                      js::SystemAllocPolicy>;
+
+    using TimeZoneMap = js::GCHashMap<TimeZoneName,
+                                      TimeZoneName,
+                                      TimeZoneHasher,
+                                      js::SystemAllocPolicy>;
+
+    /**
+     * As a threshold matter, available time zones are those time zones ICU
+     * supports, via ucal_openTimeZones. But ICU supports additional non-IANA
+     * time zones described in intl/icu/source/tools/tzcode/icuzones (listed in
+     * IntlTimeZoneData.cpp's |legacyICUTimeZones|) for its own backwards
+     * compatibility purposes. This set consists of ICU's supported time zones,
+     * minus all backwards-compatibility time zones.
+     */
+    TimeZoneSet availableTimeZones;
+
+    /**
+     * IANA treats some time zone names as Zones, that ICU instead treats as
+     * Links. For example, IANA considers "America/Indiana/Indianapolis" to be
+     * a Zone and "America/Fort_Wayne" a Link that targets it, but ICU
+     * considers the former a Link that targets "America/Indianapolis" (which
+     * IANA treats as a Link).
+     *
+     * ECMA-402 requires that we respect IANA data, so if we're asked to
+     * canonicalize a time zone name in this set, we must *not* return ICU's
+     * canonicalization.
+     */
+    TimeZoneSet ianaZonesTreatedAsLinksByICU;
+
+    /**
+     * IANA treats some time zone names as Links to one target, that ICU
+     * instead treats as either Zones, or Links to different targets. An
+     * example of the former is "Asia/Calcutta, which IANA assigns the target
+     * "Asia/Kolkata" but ICU considers its own Zone. An example of the latter
+     * is "America/Virgin", which IANA assigns the target
+     * "America/Port_of_Spain" but ICU assigns the target "America/St_Thomas".
+     *
+     * ECMA-402 requires that we respect IANA data, so if we're asked to
+     * canonicalize a time zone name that's a key in this map, we *must* return
+     * the corresponding value and *must not* return ICU's canonicalization.
+     */
+    TimeZoneMap ianaLinksCanonicalizedDifferentlyByICU;
+
+    bool timeZoneDataInitialized = false;
+
+    /**
+     * Precomputes the available time zone names, because it's too expensive to
+     * call ucal_openTimeZones() repeatedly.
+     */
+    bool ensureTimeZones(JSContext* cx);
+
+  public:
+    /**
+     * Returns the validated time zone name in |result|. If the input time zone
+     * isn't a valid IANA time zone name, |result| remains unchanged.
+     */
+    bool validateTimeZoneName(JSContext* cx, JS::HandleString timeZone,
+                              JS::MutableHandleString result);
+
+    /**
+     * Returns the canonical time zone name in |result|. If no canonical name
+     * was found, |result| remains unchanged.
+     *
+     * This method only handles time zones which are canonicalized differently
+     * by ICU when compared to IANA.
+     */
+    bool tryCanonicalizeTimeZoneConsistentWithIANA(JSContext* cx, JS::HandleString timeZone,
+                                                   JS::MutableHandleString result);
+  private:
+    using Locale = JSAtom*;
+
+    struct LocaleHasher
+    {
+        struct Lookup : LinearStringLookup
+        {
+            explicit Lookup(JSLinearString* locale);
+            Lookup(const char* chars, size_t length);
+        };
+
+        static js::HashNumber hash(const Lookup& lookup) { return lookup.hash; }
+        static bool match(Locale key, const Lookup& lookup);
+    };
+
+    using LocaleSet = GCHashSet<Locale, LocaleHasher, SystemAllocPolicy>;
+
+    // Set of supported locales for all Intl service constructors except Collator,
+    // which uses its own set.
+    //
+    // UDateFormat:
+    // udat_[count,get]Available() return the same results as their
+    // uloc_[count,get]Available() counterparts.
+    //
+    // UNumberFormatter:
+    // unum_[count,get]Available() return the same results as their
+    // uloc_[count,get]Available() counterparts.
+    //
+    // UListFormatter, UPluralRules and URelativeDateTimeFormatter:
+    // We're going to use ULocale availableLocales as per ICU recommendation:
+    // https://unicode-org.atlassian.net/browse/ICU-12756
+    LocaleSet supportedLocales;
+
+    // ucol_[count,get]Available() return different results compared to
+    // uloc_[count,get]Available(), we can't use |supportedLocales| here.
+    LocaleSet collatorSupportedLocales;
+
+    bool supportedLocalesInitialized = false;
+
+    // CountAvailable and GetAvailable describe the signatures used for ICU API
+    // to determine available locales for various functionality.
+    using CountAvailable = int32_t (*)();
+    using GetAvailable = const char* (*)(int32_t localeIndex);
+
+    static bool getAvailableLocales(JSContext* cx, LocaleSet& locales,
+                                    CountAvailable countAvailable,
+                                    GetAvailable getAvailable);
+
+    /**
+    * Precomputes the available locales sets.
+    */
+    bool ensureSupportedLocales(JSContext* cx);
+
+  public:
+    enum class SupportedLocaleKind {
+        Collator,
+        DateTimeFormat,
+        ListFormat,
+        NumberFormat,
+        PluralRules,
+        RelativeTimeFormat
+    };
+
+    /**
+    * Sets |supported| to true if |locale| is supported by the requested Intl
+    * service constructor. Otherwise sets |supported| to false.
+    */
+    [[nodiscard]] bool isSupportedLocale(JSContext* cx, SupportedLocaleKind kind,
+                                         JS::Handle<JSString*> locale,
+                                         bool* supported);
+
+  private:
+    /**
+     * The case first parameter (BCP47 key "kf") allows to switch the order of
+     * upper- and lower-case characters. ICU doesn't directly provide an API
+     * to query the default case first value of a given locale, but instead
+     * requires to instantiate a collator object and then query the case first
+     * attribute (UCOL_CASE_FIRST).
+     * To avoid instantiating an additional collator object whenever we need
+     * to retrieve the default case first value of a specific locale, we
+     * compute the default case first value for every supported locale only
+     * once and then keep a list of all locales which don't use the default
+     * case first setting.
+     * There is almost no difference between lower-case first and when case
+     * first is disabled (UCOL_LOWER_FIRST resp. UCOL_OFF), so we only need to
+     * track locales which use upper-case first as their default setting.
+     */
+
+    LocaleSet upperCaseFirstLocales;
+
+    bool upperCaseFirstInitialized = false;
+
+    /**
+     * Precomputes the available locales which use upper-case first sorting.
+     */
+    bool ensureUpperCaseFirstLocales(JSContext* cx);
+
+  public:
+    /**
+     * Sets |isUpperFirst| to true if |locale| sorts upper-case characters
+     * before lower-case characters.
+     */
+    bool isUpperCaseFirst(JSContext* cx, JS::HandleString locale, bool* isUpperFirst);
+
+  public:
+    void destroyInstance();
+
+    void trace(JSTracer* trc);
+
+    size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
+};
+
+} // namespace intl
+
+} // namespace js
+
 #endif /* builtin_intl_SharedIntlData_h */

js/src/jit/InlinableNatives.h

@@ -28,6 +28,7 @@
                                     \
     _(IntlIsCollator)               \
     _(IntlIsDateTimeFormat)         \
+    _(IntlIsListFormat)             \
     _(IntlIsNumberFormat)           \
     _(IntlIsPluralRules)            \
     _(IntlIsRelativeTimeFormat)     \

js/src/jit/MCallOptimize.cpp

@@ -14,6 +14,7 @@
 #include "builtin/TypedObject.h"
 #include "builtin/intl/Collator.h"
 #include "builtin/intl/DateTimeFormat.h"
+#include "builtin/intl/ListFormat.h"
 #include "builtin/intl/NumberFormat.h"
 #include "builtin/intl/PluralRules.h"
 #include "builtin/intl/RelativeTimeFormat.h"
@@ -113,6 +114,8 @@ IonBuilder::inlineNativeCall(CallInfo& callInfo, JSFunction* target)
         return inlineHasClass(callInfo, &CollatorObject::class_);
       case InlinableNative::IntlIsDateTimeFormat:
         return inlineHasClass(callInfo, &DateTimeFormatObject::class_);
+      case InlinableNative::IntlIsListFormat:
+        return inlineHasClass(callInfo, &ListFormatObject::class_);
       case InlinableNative::IntlIsNumberFormat:
         return inlineHasClass(callInfo, &NumberFormatObject::class_);
       case InlinableNative::IntlIsPluralRules:

js/src/jsfriendapi.h

@@ -2877,6 +2877,11 @@ ToWindowIfWindowProxy(JSObject* obj);
 extern bool
 AddMozDateTimeFormatConstructor(JSContext* cx, JS::Handle<JSObject*> intl);
 
+// Create and add the Intl.ListFormat constructor function to the provided
+// object.
+extern bool
+AddListFormatConstructor(JSContext* cx, JS::Handle<JSObject*> intl);
+
 } /* namespace js */
 
 class NativeProfiler

js/src/jsprototypes.h

@@ -96,6 +96,7 @@
     real(Symbol,                InitSymbolClass,        OCLASP(Symbol)) \
 IF_SAB(real,imaginary)(SharedArrayBuffer,     InitViaClassSpec, OCLASP(SharedArrayBuffer)) \
 IF_INTL(real,imaginary) (Intl,                InitIntlClass,          CLASP(Intl)) \
+IF_INTL(real,imaginary) (ListFormat,          InitViaClassSpec, OCLASP(ListFormat)) \
 IF_BDATA(real,imaginary)(TypedObject,         InitTypedObjectModuleObject,   OCLASP(TypedObjectModule)) \
     real(Reflect,               InitReflect,            nullptr) \
     real(WeakSet,               InitWeakSetClass,       OCLASP(WeakSet)) \

js/src/moz.build

@@ -126,6 +126,7 @@ main_deunified_sources = [
     'builtin/intl/IntlObject.cpp',
     'builtin/intl/LanguageTag.cpp',
     'builtin/intl/LanguageTagGenerated.cpp',
+    'builtin/intl/ListFormat.cpp',
     'builtin/intl/Locale.cpp',
     'builtin/intl/NumberFormat.cpp',
     'builtin/intl/PluralRules.cpp',
@@ -745,6 +746,7 @@ selfhosted.inputs = [
     'builtin/intl/CommonFunctions.js',
     'builtin/intl/DateTimeFormat.js',
     'builtin/intl/IntlObject.js',
+    'builtin/intl/ListFormat.js',
     'builtin/intl/NumberFormat.js',
     'builtin/intl/PluralRules.js',
     'builtin/intl/RelativeTimeFormat.js',

js/src/shell/js.cpp

@@ -935,6 +935,10 @@ AddIntlExtras(JSContext* cx, unsigned argc, Value* vp)
     if (!js::AddMozDateTimeFormatConstructor(cx, intl))
         return false;
 
+    if (!js::AddListFormatConstructor(cx, intl)) {
+        return false;
+    }
+
     args.rval().setUndefined();
     return true;
 }

js/src/vm/CommonPropertyNames.h

@@ -118,6 +118,7 @@
     macro(dotStaticInitializers, dotStaticInitializers, ".staticInitializers") \
     macro(dotStaticFieldKeys, dotStaticFieldKeys, ".staticFieldKeys") \
     macro(each, each, "each") \
+    macro(element, element, "element") \
     macro(elementType, elementType, "elementType") \
     macro(else, else_, "else") \
     macro(empty, empty, "") \
@@ -204,6 +205,7 @@
     macro(Infinity, Infinity, "Infinity") \
     macro(InitializeCollator, InitializeCollator, "InitializeCollator") \
     macro(InitializeDateTimeFormat, InitializeDateTimeFormat, "InitializeDateTimeFormat") \
+    macro(InitializeListFormat, InitializeListFormat, "InitializeListFormat") \
     macro(InitializeLocale, InitializeLocale, "InitializeLocale") \
     macro(InitializeNumberFormat, InitializeNumberFormat, "InitializeNumberFormat") \
     macro(InitializePluralRules, InitializePluralRules, "InitializePluralRules") \

js/src/vm/GlobalObject.cpp

@@ -29,6 +29,7 @@
 #include "builtin/WeakMapObject.h"
 #include "builtin/WeakRefObject.h"
 #include "builtin/WeakSetObject.h"
+#include "builtin/intl/ListFormat.h"
 #include "vm/Debugger.h"
 #include "vm/EnvironmentObject.h"
 #include "vm/HelperThreads.h"

js/src/vm/SelfHosting.cpp

@@ -26,6 +26,7 @@
 #include "builtin/intl/Collator.h"
 #include "builtin/intl/DateTimeFormat.h"
 #include "builtin/intl/IntlObject.h"
+#include "builtin/intl/ListFormat.h"
 #include "builtin/intl/Locale.h"
 #include "builtin/intl/NumberFormat.h"
 #include "builtin/intl/PluralRules.h"
@@ -2556,6 +2557,7 @@ static const JSFunctionSpec intrinsic_functions[] = {
     JS_FN("intl_patternForStyle", intl_patternForStyle, 6, 0),
     JS_FN("intl_GetPluralCategories", intl_GetPluralCategories, 2, 0),
     JS_FN("intl_SelectPluralRule", intl_SelectPluralRule, 2,0),
+    JS_FN("intl_FormatList", intl_FormatList, 3, 0),
     JS_FN("intl_toLocaleLowerCase", intl_toLocaleLowerCase, 2,0),
     JS_FN("intl_toLocaleUpperCase", intl_toLocaleUpperCase, 2,0),
     JS_FN("intl_ValidateAndCanonicalizeLanguageTag", intl_ValidateAndCanonicalizeLanguageTag, 2, 0),
@@ -2569,6 +2571,9 @@ static const JSFunctionSpec intrinsic_functions[] = {
     JS_INLINABLE_FN("IsDateTimeFormat",
                     intrinsic_IsInstanceOfBuiltin<DateTimeFormatObject>, 1,0,
                     IntlIsDateTimeFormat),
+    JS_INLINABLE_FN("IsListFormat",
+                    intrinsic_IsInstanceOfBuiltin<ListFormatObject>, 1, 0,
+                    IntlIsListFormat),
     JS_INLINABLE_FN("IsNumberFormat",
                     intrinsic_IsInstanceOfBuiltin<NumberFormatObject>, 1,0,
                     IntlIsNumberFormat),