Add epoch_ns_for for PlainDate/Time/DateTime

src/builtins/core/plain_date.rs

@@ -17,6 +17,7 @@ use crate::{
     },
     parsers::IxdtfStringBuilder,
     provider::{NeverProvider, TimeZoneProvider},
+    unix_time::EpochNanoseconds,
     MonthCode, TemporalError, TemporalResult, TimeZone,
 };
 use alloc::string::String;
@@ -685,6 +686,23 @@ impl PlainDate {
             epoch_ns.offset,
         )
     }
+
+    /// Gets the epochMilliseconds represented by this PlainDate in the given timezone
+    /// (at noon time)
+    ///
+    // Useful for implementing HandleDateTimeTemporalDate
+    pub fn epoch_ns_for_with_provider(
+        &self,
+        time_zone: TimeZone,
+        provider: &(impl TimeZoneProvider + ?Sized),
+    ) -> TemporalResult<EpochNanoseconds> {
+        // 2. Let isoDateTime be CombineISODateAndTimeRecord(temporalDate.[[ISODate]], NoonTimeRecord()).
+        let iso = IsoDateTime::new(self.iso, IsoTime::noon())?;
+        // 3. Let epochNs be ? GetEpochNanosecondsFor(dateTimeFormat.[[TimeZone]], isoDateTime, compatible).
+        Ok(time_zone
+            .get_epoch_nanoseconds_for(iso, Disambiguation::Compatible, provider)?
+            .ns)
+    }
 }
 
 // ==== Trait impls ====

src/builtins/core/plain_date_time.rs

@@ -19,6 +19,7 @@ use crate::{
     parsers::IxdtfStringBuilder,
     primitive::FiniteF64,
     provider::{NeverProvider, TimeZoneProvider},
+    unix_time::EpochNanoseconds,
     MonthCode, TemporalError, TemporalResult, TimeZone,
 };
 use alloc::string::String;
@@ -907,6 +908,21 @@ impl PlainDateTime {
         ))
     }
 
+    /// Gets the epochMilliseconds represented by this PlainDateTime in the given timezone
+    ///
+    // Useful for implementing HandleDateTimeTemporalDateTime
+    pub fn epoch_ns_for_with_provider(
+        &self,
+        time_zone: TimeZone,
+        provider: &(impl TimeZoneProvider + ?Sized),
+    ) -> TemporalResult<EpochNanoseconds> {
+        //  Let epochNs be ? GetEpochNanosecondsFor(dateTimeFormat.[[TimeZone]],
+        //  isoDateTime, compatible).
+        Ok(time_zone
+            .get_epoch_nanoseconds_for(self.iso, Disambiguation::Compatible, provider)?
+            .ns)
+    }
+
     /// Create a [`PlainDate`] from the current `PlainDateTime`.
     #[inline]
     pub fn to_plain_date(&self) -> PlainDate {

src/builtins/core/plain_time.rs

@@ -7,12 +7,15 @@ use crate::{
     },
     error::ErrorMessage,
     iso::IsoTime,
+    iso::{IsoDate, IsoDateTime},
     options::{
-        DifferenceOperation, DifferenceSettings, Overflow, ResolvedRoundingOptions,
+        DifferenceOperation, DifferenceSettings, Disambiguation, Overflow, ResolvedRoundingOptions,
         RoundingOptions, ToStringRoundingOptions, Unit, UnitGroup,
     },
     parsers::{parse_time, IxdtfStringBuilder},
-    TemporalError, TemporalResult,
+    provider::TimeZoneProvider,
+    unix_time::EpochNanoseconds,
+    TemporalError, TemporalResult, TimeZone,
 };
 use alloc::string::String;
 use core::str::FromStr;
@@ -541,6 +544,22 @@ impl PlainTime {
         let builder = IxdtfStringBuilder::default().with_time(result, resolved.precision);
         Ok(builder)
     }
+    /// Gets the epochMilliseconds represented by this PlainTime in the given timezone
+    /// (on Jan 1 1970)
+    ///
+    // Useful for implementing HandleDateTimeTemporalTime
+    pub fn epoch_ns_for_with_provider(
+        &self,
+        time_zone: TimeZone,
+        provider: &(impl TimeZoneProvider + ?Sized),
+    ) -> TemporalResult<EpochNanoseconds> {
+        // 2. Let isoDateTime be CombineISODateAndTimeRecord(temporalDate.[[ISODate]], NoonTimeRecord()).
+        let iso = IsoDateTime::new(IsoDate::UNIX_EPOCH, self.iso)?;
+        // 3. Let epochNs be ? GetEpochNanosecondsFor(dateTimeFormat.[[TimeZone]], isoDateTime, compatible).
+        Ok(time_zone
+            .get_epoch_nanoseconds_for(iso, Disambiguation::Compatible, provider)?
+            .ns)
+    }
 }
 
 impl From<PlainDateTime> for PlainTime {

src/iso.rs

@@ -264,6 +264,7 @@ pub struct IsoDate {
 }
 
 impl IsoDate {
+    pub(crate) const UNIX_EPOCH: Self = Self::new_unchecked(1970, 1, 1);
     /// Creates a new `IsoDate` without determining the validity.
     pub(crate) const fn new_unchecked(year: i32, month: u8, day: u8) -> Self {
         Self { year, month, day }