Add jiff example (#5997)

This is the 2.0 version of
https://docs.rs/jiff/latest/jiff/_documentation/comparison/index.html#icu-v150

components/icu/Cargo.toml

@@ -48,6 +48,7 @@ icu_datetime = { path = "../../components/datetime", features = ["serde"] }
 icu_provider_adapters = { path = "../../provider/adapters", features = ["serde"] }
 icu_provider_blob = { path = "../../provider/blob" }
 writeable = { path = "../../utils/writeable" }
+jiff = "0.1"
 
 [features]
 default = [
@@ -134,3 +135,6 @@ skip_feature_sets = [[]]
 [[example]]
 name = "tui"
 required-features = ["serde"]
+
+[[example]]
+name = "jiff"

components/icu/examples/jiff.rs

@@ -0,0 +1,66 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use icu::{
+    calendar::Date,
+    datetime::{fieldsets, DateTimeFormatter},
+    locale::locale,
+    timezone::{IxdtfParser, Time, TimeZoneIdMapper, UtcOffset, ZoneVariant, ZonedDateTime},
+};
+
+fn main() -> Result<(), Box<dyn core::error::Error>> {
+    let ts: jiff::Timestamp = "2024-09-10T23:37:20.123456789Z".parse()?;
+    let zoned: jiff::Zoned = ts.intz("Asia/Tokyo")?;
+
+    // Convert to ICU types
+    let date = Date::try_new_iso(
+        i32::from(zoned.year()),
+        zoned.month().unsigned_abs(),
+        zoned.day().unsigned_abs(),
+    )?;
+
+    let time = Time::try_new(
+        zoned.hour().unsigned_abs(),
+        zoned.minute().unsigned_abs(),
+        zoned.second().unsigned_abs(),
+        u32::from(zoned.millisecond().unsigned_abs()) * 1_000_000
+            + u32::from(zoned.microsecond().unsigned_abs()) * 1_000
+            + u32::from(zoned.nanosecond().unsigned_abs()),
+    )?;
+
+    let zone =
+        // ICU uses BCP47 time zone IDs
+        TimeZoneIdMapper::new().iana_to_bcp47(zoned.time_zone().iana_name().unwrap_or("Etc/Unknown"))
+        // In ICU's model, a time zone has a fixed offset, as that's required for formatting
+        .with_offset(UtcOffset::try_from_seconds(zoned.offset().seconds()).ok())
+        // Display names might change over time for a given zone (e.g. it might change from Eastern Time to
+        // Central Time), so the ICU timezone needs a reference date and time.
+        .at_time((date, time))
+        // And finally, the zone variant is also required for formatting
+        .with_zone_variant(match zoned.time_zone().to_offset(zoned.timestamp()).1 {
+            jiff::tz::Dst::Yes => ZoneVariant::Daylight,
+            jiff::tz::Dst::No => ZoneVariant::Standard,
+        });
+
+    let zoned_date_time = ZonedDateTime { date, time, zone };
+
+    // Alternatively, the ICU ZonedDateTime can be parsed from a serialized IXDTF string.
+    assert_eq!(
+        IxdtfParser::new()
+            .try_iso_from_str(&zoned.to_string())
+            .unwrap(),
+        zoned_date_time
+    );
+
+    // Preferences for an English formatter using the Japanese calendar
+    let prefs = locale!("en-GB-u-ca-japanese").into();
+
+    // A medium-length year-month-day-time-specific-zone formatter
+    let formatter =
+        DateTimeFormatter::try_new(prefs, fieldsets::YMDT::medium().with_zone_specific_long())?;
+
+    println!("{}", formatter.format_any_calendar(&zoned_date_time)); // 11 Sept 6 Reiwa, 08:37:20 Japan Standard Time
+
+    Ok(())
+}

components/timezone/src/ixdtf.rs

@@ -322,7 +322,12 @@ impl<'a> Intermediate<'a> {
         };
         let time_zone_id = mapper.iana_bytes_to_bcp47(iana_identifier);
         let date = Date::<Iso>::try_new_iso(self.date.year, self.date.month, self.date.day)?;
-        let time = Time::try_new(self.time.hour, self.time.minute, self.time.second, 0)?;
+        let time = Time::try_new(
+            self.time.hour,
+            self.time.minute,
+            self.time.second,
+            self.time.nanosecond,
+        )?;
         let offset = match time_zone_id.as_str() {
             "utc" | "gmt" => Some(UtcOffset::zero()),
             _ => None,
@@ -358,7 +363,12 @@ impl<'a> Intermediate<'a> {
             },
         };
         let date = Date::<Iso>::try_new_iso(self.date.year, self.date.month, self.date.day)?;
-        let time = Time::try_new(self.time.hour, self.time.minute, self.time.second, 0)?;
+        let time = Time::try_new(
+            self.time.hour,
+            self.time.minute,
+            self.time.second,
+            self.time.nanosecond,
+        )?;
         Ok(time_zone_id.with_offset(offset).at_time((date, time)))
     }
 
@@ -375,7 +385,12 @@ impl<'a> Intermediate<'a> {
         };
         let time_zone_id = mapper.iana_bytes_to_bcp47(iana_identifier);
         let date = Date::try_new_iso(self.date.year, self.date.month, self.date.day)?;
-        let time = Time::try_new(self.time.hour, self.time.minute, self.time.second, 0)?;
+        let time = Time::try_new(
+            self.time.hour,
+            self.time.minute,
+            self.time.second,
+            self.time.nanosecond,
+        )?;
         let offset = UtcOffset::try_from_utc_offset_record(offset)?;
         let zone_variant = match zone_offset_calculator
             .compute_offsets_from_time_zone(time_zone_id, (date, time))