LibJS: Start implementing Temporal.Duration

This patch adds the Duration object itself, its constructor and
prototype (currently empty), and three required abstract operations.

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

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/AbstractOperations.h>
+#include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/Temporal/Duration.h>
+#include <LibJS/Runtime/Temporal/DurationConstructor.h>
+
+namespace JS::Temporal {
+
+// 7 Temporal.Duration Objects, https://tc39.es/proposal-temporal/#sec-temporal-duration-objects
+Duration::Duration(double years, double months, double weeks, double days, double hours, double minutes, double seconds, double milliseconds, double microseconds, double nanoseconds, Object& prototype)
+    : Object(prototype)
+    , m_years(years)
+    , m_months(months)
+    , m_weeks(weeks)
+    , m_days(days)
+    , m_hours(hours)
+    , m_minutes(minutes)
+    , m_seconds(seconds)
+    , m_milliseconds(milliseconds)
+    , m_microseconds(microseconds)
+    , m_nanoseconds(nanoseconds)
+{
+}
+
+// 7.5.3 DurationSign ( years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds )
+i8 duration_sign(double years, double months, double weeks, double days, double hours, double minutes, double seconds, double milliseconds, double microseconds, double nanoseconds)
+{
+    // 1. For each value v of « years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds », do
+    for (auto& v : { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds }) {
+        // a. If v < 0, return −1.
+        if (v < 0)
+            return -1;
+
+        // b. If v > 0, return 1.
+        if (v > 0)
+            return 1;
+    }
+
+    // 2. Return 0.
+    return 0;
+}
+
+// 7.5.4 IsValidDuration ( years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds )
+bool is_valid_duration(double years, double months, double weeks, double days, double hours, double minutes, double seconds, double milliseconds, double microseconds, double nanoseconds)
+{
+    // 1. Let sign be ! DurationSign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds).
+    auto sign = duration_sign(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
+
+    // 2. For each value v of « years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds », do
+    for (auto& v : { years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds }) {
+        // a. If v is not finite, return false.
+        if (!isfinite(v))
+            return false;
+
+        // b. If v < 0 and sign > 0, return false.
+        if (v < 0 && sign > 0)
+            return false;
+
+        // c. If v > 0 and sign < 0, return false.
+        if (v > 0 && sign < 0)
+            return false;
+    }
+
+    // 3. Return true.
+    return true;
+}
+
+// 7.5.7 CreateTemporalDuration ( years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds [ , newTarget ] ), https://tc39.es/proposal-temporal/#sec-temporal-createtemporalduration
+Duration* create_temporal_duration(GlobalObject& global_object, double years, double months, double weeks, double days, double hours, double minutes, double seconds, double milliseconds, double microseconds, double nanoseconds, FunctionObject* new_target)
+{
+    auto& vm = global_object.vm();
+
+    // 1. If ! IsValidDuration(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds) is false, throw a RangeError exception.
+    if (!is_valid_duration(years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds)) {
+        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidDuration);
+        return {};
+    }
+
+    // 2. If newTarget is not present, set it to %Temporal.Duration%.
+    if (!new_target)
+        new_target = global_object.temporal_duration_constructor();
+
+    // 3. Let object be ? OrdinaryCreateFromConstructor(newTarget, "%Temporal.Duration.prototype%", « [[InitializedTemporalDuration]], [[Years]], [[Months]], [[Weeks]], [[Days]], [[Hours]], [[Minutes]], [[Seconds]], [[Milliseconds]], [[Microseconds]], [[Nanoseconds]] »).
+    // 4. Set object.[[Years]] to years.
+    // 5. Set object.[[Months]] to months.
+    // 6. Set object.[[Weeks]] to weeks.
+    // 7. Set object.[[Days]] to days.
+    // 8. Set object.[[Hours]] to hours.
+    // 9. Set object.[[Minutes]] to minutes.
+    // 10. Set object.[[Seconds]] to seconds.
+    // 11. Set object.[[Milliseconds]] to milliseconds.
+    // 12. Set object.[[Microseconds]] to microseconds.
+    // 13. Set object.[[Nanoseconds]] to nanoseconds.
+    auto* object = ordinary_create_from_constructor<Duration>(global_object, *new_target, &GlobalObject::temporal_duration_prototype, years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
+    if (vm.exception())
+        return {};
+
+    // 14. Return object.
+    return object;
+}
+
+}