1 files changed, 190 insertions, 0 deletions
diff --git a/third_party/rust/plist/src/date.rs b/third_party/rust/plist/src/date.rs
new file mode 100644
index 0000000000..ff9839243b
--- /dev/null
+++ b/third_party/rust/plist/src/date.rs
@@ -0,0 +1,190 @@
+use std::{
+    fmt,
+    time::{Duration, SystemTime, UNIX_EPOCH},
+};
+use time::{format_description::well_known::Rfc3339, OffsetDateTime, UtcOffset};
+
+/// A UTC timestamp used for serialization to and from the plist date type.
+///
+/// Note that while this type implements `Serialize` and `Deserialize` it will behave strangely if
+/// used with serializers from outside this crate.
+#[derive(Clone, Copy, Eq, Hash, PartialEq)]
+pub struct Date {
+    inner: SystemTime,
+}
+
+pub(crate) struct InfiniteOrNanDate;
+
+impl Date {
+    /// The unix timestamp of the plist epoch.
+    const PLIST_EPOCH_UNIX_TIMESTAMP: Duration = Duration::from_secs(978_307_200);
+
+    pub(crate) fn from_rfc3339(date: &str) -> Result<Self, ()> {
+        let offset: OffsetDateTime = OffsetDateTime::parse(date, &Rfc3339)
+            .map_err(|_| ())?
+            .to_offset(UtcOffset::UTC);
+        Ok(Date {
+            inner: offset.into(),
+        })
+    }
+
+    pub(crate) fn to_rfc3339(&self) -> String {
+        let datetime: OffsetDateTime = self.inner.into();
+        datetime.format(&Rfc3339).unwrap()
+    }
+
+    pub(crate) fn from_seconds_since_plist_epoch(
+        timestamp: f64,
+    ) -> Result<Date, InfiniteOrNanDate> {
+        // `timestamp` is the number of seconds since the plist epoch of 1/1/2001 00:00:00.
+        let plist_epoch = UNIX_EPOCH + Date::PLIST_EPOCH_UNIX_TIMESTAMP;
+
+        if !timestamp.is_finite() {
+            return Err(InfiniteOrNanDate);
+        }
+
+        let is_negative = timestamp < 0.0;
+        let timestamp = timestamp.abs();
+        let seconds = timestamp.floor() as u64;
+        let subsec_nanos = (timestamp.fract() * 1e9) as u32;
+
+        let dur_since_plist_epoch = Duration::new(seconds, subsec_nanos);
+
+        let inner = if is_negative {
+            plist_epoch.checked_sub(dur_since_plist_epoch)
+        } else {
+            plist_epoch.checked_add(dur_since_plist_epoch)
+        };
+
+        let inner = inner.ok_or(InfiniteOrNanDate)?;
+
+        Ok(Date { inner })
+    }
+
+    pub(crate) fn to_seconds_since_plist_epoch(&self) -> f64 {
+        // needed until #![feature(duration_float)] is stabilized
+        fn as_secs_f64(d: Duration) -> f64 {
+            const NANOS_PER_SEC: f64 = 1_000_000_000.00;
+            (d.as_secs() as f64) + f64::from(d.subsec_nanos()) / NANOS_PER_SEC
+        }
+
+        let plist_epoch = UNIX_EPOCH + Date::PLIST_EPOCH_UNIX_TIMESTAMP;
+        match self.inner.duration_since(plist_epoch) {
+            Ok(dur_since_plist_epoch) => as_secs_f64(dur_since_plist_epoch),
+            Err(err) => -as_secs_f64(err.duration()),
+        }
+    }
+}
+
+impl fmt::Debug for Date {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(f, "{}", self.to_rfc3339())
+    }
+}
+
+impl From<SystemTime> for Date {
+    fn from(date: SystemTime) -> Self {
+        Date { inner: date }
+    }
+}
+
+impl Into<SystemTime> for Date {
+    fn into(self) -> SystemTime {
+        self.inner
+    }
+}
+
+#[cfg(feature = "serde")]
+pub mod serde_impls {
+    use serde::{
+        de::{Deserialize, Deserializer, Error, Unexpected, Visitor},
+        ser::{Serialize, Serializer},
+    };
+    use std::fmt;
+
+    use crate::Date;
+
+    pub const DATE_NEWTYPE_STRUCT_NAME: &str = "PLIST-DATE";
+
+    impl Serialize for Date {
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: Serializer,
+        {
+            let date_str = self.to_rfc3339();
+            serializer.serialize_newtype_struct(DATE_NEWTYPE_STRUCT_NAME, &date_str)
+        }
+    }
+
+    struct DateNewtypeVisitor;
+
+    impl<'de> Visitor<'de> for DateNewtypeVisitor {
+        type Value = Date;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str("a plist date newtype")
+        }
+
+        fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+        where
+            E: Error,
+        {
+            DateStrVisitor.visit_str(v)
+        }
+
+        fn visit_newtype_struct<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            deserializer.deserialize_str(DateStrVisitor)
+        }
+    }
+
+    struct DateStrVisitor;
+
+    impl<'de> Visitor<'de> for DateStrVisitor {
+        type Value = Date;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str("a plist date string")
+        }
+
+        fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+        where
+            E: Error,
+        {
+            Date::from_rfc3339(v).map_err(|()| E::invalid_value(Unexpected::Str(v), &self))
+        }
+    }
+
+    impl<'de> Deserialize<'de> for Date {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            deserializer.deserialize_newtype_struct(DATE_NEWTYPE_STRUCT_NAME, DateNewtypeVisitor)
+        }
+    }
+}
+
+#[cfg(test)]
+mod testing {
+    use super::*;
+
+    #[test]
+    fn date_roundtrip() {
+        let date_str = "1981-05-16T11:32:06Z";
+
+        let date = Date::from_rfc3339(date_str).expect("should parse");
+
+        let generated_str = date.to_rfc3339();
+
+        assert_eq!(date_str, generated_str);
+    }
+
+    #[test]
+    fn far_past_date() {
+        let date_str = "1920-01-01T00:00:00Z";
+        Date::from_rfc3339(date_str).expect("should parse");
+    }
+}