Implement DateTimeFormat.format for non android/ios environments (#1362)

Summary:
Related to #1350 and #1211
Follow up of #1361

I'd like to expand non iOS/android support of `Intl`. In this case, I'm implementing both `DateTimeFormat.prototype.resolvedOptions` and `DateTimeFormat.prototype.format`. The implementation is a mix from the Apple and hermes-windows' implementations.

- created `PlatformIntlShared` with helper functions that are exactly the same between Apple and ICU
- Implemented `DateTimeFormatICU` based on `DateTimeFormatApple`
    - Used an ICU equivalent whenever NS was used for Apple

Pull Request resolved: #1362

Test Plan: Testing against `test262/test/intl402/DateTimeFormat`

Reviewed By: tmikov

Differential Revision: D55893825

Pulled By: neildhar

fbshipit-source-id: 03eef39721915ef03ebf6859980c374e10d337e9

include/hermes/Platform/Intl/PlatformIntlShared.h

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#ifndef HERMES_PLATFORMINTL_PLATFORMINTLSHARED_H
+#define HERMES_PLATFORMINTL_PLATFORMINTLSHARED_H
+
+#ifdef HERMES_ENABLE_INTL
+#include "hermes/Platform/Intl/PlatformIntl.h"
+
+namespace hermes {
+namespace platform_intl {
+
+struct LocaleMatch {
+  std::u16string locale;
+  std::map<std::u16string, std::u16string> extensions;
+};
+
+struct ResolvedLocale {
+  std::u16string locale;
+  std::u16string dataLocale;
+  std::unordered_map<std::u16string, std::u16string> extensions;
+};
+
+/// https://402.ecma-international.org/8.0/#sec-canonicalizelocalelist
+vm::CallResult<std::vector<std::u16string>> canonicalizeLocaleList(
+    vm::Runtime &runtime,
+    const std::vector<std::u16string> &locales);
+
+/// https://402.ecma-international.org/8.0/#sec-intl.getcanonicallocales
+vm::CallResult<std::vector<std::u16string>> getCanonicalLocales(
+    vm::Runtime &runtime,
+    const std::vector<std::u16string> &locales);
+
+/// https://402.ecma-international.org/8.0/#sec-bestavailablelocale
+std::optional<std::u16string> bestAvailableLocale(
+    const std::vector<std::u16string> &availableLocales,
+    const std::u16string &locale);
+
+/// https://402.ecma-international.org/8.0/#sec-lookupsupportedlocales
+std::vector<std::u16string> lookupSupportedLocales(
+    const std::vector<std::u16string> &availableLocales,
+    const std::vector<std::u16string> &requestedLocales);
+
+/// https://402.ecma-international.org/8.0/#sec-supportedlocales
+std::vector<std::u16string> supportedLocales(
+    const std::vector<std::u16string> &availableLocales,
+    const std::vector<std::u16string> &requestedLocales);
+
+/// https://402.ecma-international.org/8.0/#sec-getoption
+vm::CallResult<std::optional<std::u16string>> getOptionString(
+    vm::Runtime &runtime,
+    const Options &options,
+    const std::u16string &property,
+    llvh::ArrayRef<std::u16string_view> values,
+    std::optional<std::u16string_view> fallback);
+
+/// https://402.ecma-international.org/8.0/#sec-getoption
+std::optional<bool> getOptionBool(
+    vm::Runtime &runtime,
+    const Options &options,
+    const std::u16string &property,
+    std::optional<bool> fallback);
+
+/// https://402.ecma-international.org/8.0/#sec-todatetimeoptions
+vm::CallResult<Options> toDateTimeOptions(
+    vm::Runtime &runtime,
+    Options options,
+    std::u16string_view required,
+    std::u16string_view defaults);
+
+/// https://402.ecma-international.org/8.0/#sec-case-sensitivity-and-case-mapping
+std::u16string toASCIIUppercase(std::u16string_view tz);
+
+/// https://402.ecma-international.org/8.0/#sec-defaultnumberoption
+vm::CallResult<std::optional<uint8_t>> defaultNumberOption(
+    vm::Runtime &runtime,
+    const std::u16string &property,
+    std::optional<Option> value,
+    const std::uint8_t minimum,
+    const std::uint8_t maximum,
+    std::optional<uint8_t> fallback);
+
+/// https://402.ecma-international.org/8.0/#sec-getoption
+vm::CallResult<std::optional<uint8_t>> getNumberOption(
+    vm::Runtime &runtime,
+    const Options &options,
+    const std::u16string &property,
+    const std::uint8_t minimum,
+    const std::uint8_t maximum,
+    std::optional<uint8_t> fallback);
+} // namespace platform_intl
+} // namespace hermes
+
+#endif
+
+#endif

lib/Platform/Intl/CMakeLists.txt

@@ -22,10 +22,11 @@ if(HERMES_ENABLE_INTL)
     set_target_properties(hermesPlatformIntl PROPERTIES UNITY_BUILD false)
     target_compile_options(hermesPlatformIntl PRIVATE -fobjc-arc)
   else()
-    add_hermes_library(hermesPlatformIntl STATIC PlatformIntlICU.cpp
+    add_hermes_library(hermesPlatformIntl STATIC PlatformIntlICU.cpp PlatformIntlShared.cpp
         LINK_LIBS
         hermesBCP47Parser
         hermesPublic
     )
+    hermes_link_icu(hermesPlatformIntl)
   endif()
 endif()