LibJS: Implement Temporal's Time Zone Methods Record

Similar to 'Calendar Methods Record', this is part of a refactor to the
temporal spec which will need much work for all of the corresponding AOs
to be updated to use.

Put in a new header file to prevent circular include problems when using
this new record.

Userland/Libraries/LibJS/Runtime/Temporal/TimeZoneMethods.cpp

@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/AbstractOperations.h>
+#include <LibJS/Runtime/Temporal/TimeZone.h>
+#include <LibJS/Runtime/Temporal/TimeZoneMethods.h>
+
+namespace JS::Temporal {
+
+// 11.5.2 CreateTimeZoneMethodsRecord ( timeZone, methods ), https://tc39.es/proposal-temporal/#sec-temporal-createtimezonemethodsrecord
+ThrowCompletionOr<TimeZoneMethods> create_time_zone_methods_record(VM& vm, Variant<String, NonnullGCPtr<Object>> time_zone, ReadonlySpan<TimeZoneMethod> methods)
+{
+    // 1. Let record be the Time Zone Methods Record { [[Receiver]]: timeZone, [[GetOffsetNanosecondsFor]]: undefined, [[GetPossibleInstantsFor]]: undefined  }.
+    TimeZoneMethods record {
+        .receiver = move(time_zone),
+        .get_offset_nanoseconds_for = nullptr,
+        .get_possible_instants_for = nullptr,
+    };
+
+    // 2. For each element methodName in methods, do
+    for (TimeZoneMethod method_name : methods) {
+        // a. Perform ? TimeZoneMethodsRecordLookup(record, methodName).
+        TRY(time_zone_methods_record_lookup(vm, record, method_name));
+    }
+
+    // 3. Return record.
+    return record;
+}
+
+// 11.5.3 TimeZoneMethodsRecordLookup ( timeZoneRec, methodName ), https://tc39.es/proposal-temporal/#sec-temporal-timezonemethodsrecordlookup
+ThrowCompletionOr<void> time_zone_methods_record_lookup(VM& vm, TimeZoneMethods& time_zone_record, TimeZoneMethod method_name)
+{
+    auto& realm = *vm.current_realm();
+
+    // 1. Assert: TimeZoneMethodsRecordHasLookedUp(timeZoneRec, methodName) is false.
+    // 2. If methodName is GET-OFFSET-NANOSECONDS-FOR, then
+    //     a. If timeZoneRec.[[Receiver]] is a String, then
+    //         i. Set timeZoneRec.[[GetOffsetNanosecondsFor]] to %Temporal.TimeZone.prototype.getOffsetNanosecondsFor%.
+    //     b. Else,
+    //         i. Set timeZoneRec.[[GetOffsetNanosecondsFor]] to ? GetMethod(timeZoneRec.[[Receiver]], "getOffsetNanosecondsFor").
+    //         ii. If timeZoneRec.[[GetOffsetNanosecondsFor]] is undefined, throw a TypeError exception.
+    // 3. Else if methodName is GET-POSSIBLE-INSTANTS-FOR, then
+    //     a. If timeZoneRec.[[Receiver]] is a String, then
+    //         i. Set timeZoneRec.[[GetPossibleInstantsFor]] to %Temporal.TimeZone.prototype.getPossibleInstantsFor%.
+    //     b. Else,
+    //         i. Set timeZoneRec.[[GetPossibleInstantsFor]] to ? GetMethod(timeZoneRec.[[Receiver]], "getPossibleInstantsFor").
+    //         ii. If timeZoneRec.[[GetPossibleInstantsFor]] is undefined, throw a TypeError exception.
+    switch (method_name) {
+#define __JS_ENUMERATE(PascalName, camelName, snake_name)                                                                 \
+    case TimeZoneMethod::PascalName: {                                                                                    \
+        VERIFY(!time_zone_record.snake_name);                                                                             \
+        if (time_zone_record.receiver.has<String>()) {                                                                    \
+            const auto& time_zone_prototype = *realm.intrinsics().temporal_time_zone_prototype();                         \
+            time_zone_record.snake_name = time_zone_prototype.get_without_side_effects(vm.names.camelName).as_function(); \
+        } else {                                                                                                          \
+            Value time_zone { time_zone_record.receiver.get<NonnullGCPtr<Object>>() };                                    \
+            time_zone_record.snake_name = TRY(time_zone.get_method(vm, vm.names.camelName));                              \
+            if (!time_zone_record.snake_name)                                                                             \
+                return vm.throw_completion<TypeError>(ErrorType::IsUndefined, #camelName##sv);                            \
+        }                                                                                                                 \
+        break;                                                                                                            \
+    }
+        JS_ENUMERATE_TIME_ZONE_METHODS
+#undef __JS_ENUMERATE
+    }
+    // 4. Return UNUSED.
+    return {};
+}
+
+// 11.5.4 TimeZoneMethodsRecordHasLookedUp ( timeZoneRec, methodName ), https://tc39.es/proposal-temporal/#sec-temporal-timezonemethodsrecordhaslookedup
+bool time_zone_methods_record_has_looked_up(TimeZoneMethods const& time_zone_record, TimeZoneMethod method_name)
+{
+    // 1. If methodName is GET-OFFSET-NANOSECONDS-FOR, then
+    //     a. Let method be timeZoneRec.[[GetOffsetNanosecondsFor]].
+    // 2. Else if methodName is GET-POSSIBLE-INSTANTS-FOR, then
+    //     a. Let method be timeZoneRec.[[GetPossibleInstantsFor]].
+    // 3. If method is undefined, return false.
+    // 4. Return true.
+    switch (method_name) {
+#define __JS_ENUMERATE(PascalName, camelName, snake_name) \
+    case TimeZoneMethod::PascalName: {                    \
+        return time_zone_record.snake_name != nullptr;    \
+    }
+        JS_ENUMERATE_TIME_ZONE_METHODS
+#undef __JS_ENUMERATE
+    }
+    VERIFY_NOT_REACHED();
+}
+
+// 11.5.5 TimeZoneMethodsRecordIsBuiltin ( timeZoneRec ), https://tc39.es/proposal-temporal/#sec-temporal-timezonemethodsrecordisbuiltin
+bool time_zone_methods_record_is_builtin(TimeZoneMethods const& time_zone_record)
+{
+    // 1. If timeZoneRec.[[Receiver]] is a String, return true.
+    if (time_zone_record.receiver.has<String>())
+        return true;
+
+    // 2. Return false.
+    return false;
+}
+
+// 11.5.6 TimeZoneMethodsRecordCall ( timeZoneRec, methodName, arguments ), https://tc39.es/proposal-temporal/#sec-temporal-timezonemethodsrecordcall
+ThrowCompletionOr<Value> time_zone_methods_record_call(VM& vm, TimeZoneMethods const& time_zone_record, TimeZoneMethod method_name, ReadonlySpan<Value> arguments)
+{
+    // 1. Assert: TimeZoneMethodsRecordHasLookedUp(timeZoneRec, methodName) is true.
+    VERIFY(time_zone_methods_record_has_looked_up(time_zone_record, method_name));
+
+    // 2. Let receiver be timeZoneRec.[[Receiver]].
+    // 3. If TimeZoneMethodsRecordIsBuiltin(timeZoneRec) is true, then
+    //     a. Set receiver to ! CreateTemporalTimeZone(timeZoneRec.[[Receiver]]).
+    GCPtr<Object> receiver;
+    if (time_zone_methods_record_is_builtin(time_zone_record))
+        receiver = MUST(create_temporal_time_zone(vm, time_zone_record.receiver.get<String>()));
+    else
+        receiver = time_zone_record.receiver.get<NonnullGCPtr<Object>>();
+
+    // 4. If methodName is GET-OFFSET-NANOSECONDS-FOR, then
+    //     a. Return ? Call(timeZoneRec.[[GetOffsetNanosecondsFor]], receiver, arguments).
+    // 5. If methodName is GET-POSSIBLE-INSTANTS-FOR, then
+    //     a. Return ? Call(timeZoneRec.[[GetPossibleInstantsFor]], receiver, arguments).
+    switch (method_name) {
+#define __JS_ENUMERATE(PascalName, camelName, snake_name)                       \
+    case TimeZoneMethod::PascalName: {                                          \
+        return TRY(call(vm, time_zone_record.snake_name, receiver, arguments)); \
+    }
+        JS_ENUMERATE_TIME_ZONE_METHODS
+#undef __JS_ENUMERATE
+    }
+    VERIFY_NOT_REACHED();
+}
+
+}