feat(datetime): impl Serialize/Deserialize for Date/Time

crates/toml/tests/testsuite/serde.rs

@@ -1270,6 +1270,114 @@ fn datetime_offset_issue_496() {
     assert_data_eq!(output, original.raw());
 }
 
+#[test]
+fn serialize_date() {
+    use toml::value::Date;
+
+    #[derive(Serialize)]
+    struct Document {
+        date: Date,
+    }
+
+    let input = Document {
+        date: Date {
+            year: 2024,
+            month: 1,
+            day: 1,
+        },
+    };
+    let raw = toml::to_string(&input).unwrap();
+    assert_data_eq!(
+        raw,
+        str![[r#"
+date = 2024-01-01
+
+"#]]
+        .raw()
+    );
+}
+
+#[test]
+fn serialize_time() {
+    use toml::value::Time;
+
+    #[derive(Serialize)]
+    struct Document {
+        date: Time,
+    }
+
+    let input = Document {
+        date: Time {
+            hour: 5,
+            minute: 0,
+            second: 0,
+            nanosecond: 0,
+        },
+    };
+    let raw = toml::to_string(&input).unwrap();
+    assert_data_eq!(
+        raw,
+        str![[r#"
+date = 05:00:00
+
+"#]]
+        .raw()
+    );
+}
+
+#[test]
+fn deserialize_date() {
+    use toml::value::Date;
+
+    #[derive(Debug, Deserialize)]
+    struct Document {
+        date: Date,
+    }
+
+    let document: Document = toml::from_str("date = 2024-01-01").unwrap();
+    assert_eq!(
+        document.date,
+        Date {
+            year: 2024,
+            month: 1,
+            day: 1
+        }
+    );
+
+    let err = toml::from_str::<Document>("date = 2024-01-01T05:00:00").unwrap_err();
+    assert_data_eq!(
+        err.message(),
+        str!["invalid type: local datetime, expected local date"]
+    );
+}
+
+#[test]
+fn deserialize_time() {
+    use toml::value::Time;
+
+    #[derive(Debug, Deserialize)]
+    struct Document {
+        time: Time,
+    }
+
+    let document: Document = toml::from_str("time = 05:00:00").unwrap();
+    assert_eq!(
+        document.time,
+        Time {
+            hour: 5,
+            minute: 0,
+            second: 0,
+            nanosecond: 0,
+        }
+    );
+
+    let err = toml::from_str::<Document>("time = 2024-01-01T05:00:00").unwrap_err();
+    assert_data_eq!(
+        err.message(),
+        str!["invalid type: local datetime, expected local time"]
+    );
+}
+
 #[test]
 fn serialize_array_with_none_value() {
     #[derive(Serialize)]

crates/toml_datetime/src/datetime.rs

@@ -184,6 +184,37 @@ pub enum Offset {
     },
 }
 
+impl Datetime {
+    #[cfg(feature = "serde")]
+    fn type_name(&self) -> &'static str {
+        match (
+            self.date.is_some(),
+            self.time.is_some(),
+            self.offset.is_some(),
+        ) {
+            (true, true, true) => "offset datetime",
+            (true, true, false) => "local datetime",
+            (true, false, false) => Date::type_name(),
+            (false, true, false) => Time::type_name(),
+            _ => unreachable!("unsupported datetime combination"),
+        }
+    }
+}
+
+impl Date {
+    #[cfg(feature = "serde")]
+    fn type_name() -> &'static str {
+        "local date"
+    }
+}
+
+impl Time {
+    #[cfg(feature = "serde")]
+    fn type_name() -> &'static str {
+        "local time"
+    }
+}
+
 impl From<Date> for Datetime {
     fn from(other: Date) -> Self {
         Datetime {
@@ -480,6 +511,26 @@ impl ser::Serialize for Datetime {
     }
 }
 
+#[cfg(feature = "serde")]
+impl ser::Serialize for Date {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: ser::Serializer,
+    {
+        Datetime::from(*self).serialize(serializer)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl ser::Serialize for Time {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: ser::Serializer,
+    {
+        Datetime::from(*self).serialize(serializer)
+    }
+}
+
 #[cfg(feature = "serde")]
 impl<'de> de::Deserialize<'de> for Datetime {
     fn deserialize<D>(deserializer: D) -> Result<Datetime, D::Error>
@@ -513,6 +564,46 @@ impl<'de> de::Deserialize<'de> for Datetime {
     }
 }
 
+#[cfg(feature = "serde")]
+impl<'de> de::Deserialize<'de> for Date {
+    fn deserialize<D>(deserializer: D) -> Result<Date, D::Error>
+    where
+        D: de::Deserializer<'de>,
+    {
+        match Datetime::deserialize(deserializer)? {
+            Datetime {
+                date: Some(date),
+                time: None,
+                offset: None,
+            } => Ok(date),
+            datetime => Err(de::Error::invalid_type(
+                de::Unexpected::Other(datetime.type_name()),
+                &Self::type_name(),
+            )),
+        }
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<'de> de::Deserialize<'de> for Time {
+    fn deserialize<D>(deserializer: D) -> Result<Time, D::Error>
+    where
+        D: de::Deserializer<'de>,
+    {
+        match Datetime::deserialize(deserializer)? {
+            Datetime {
+                date: None,
+                time: Some(time),
+                offset: None,
+            } => Ok(time),
+            datetime => Err(de::Error::invalid_type(
+                de::Unexpected::Other(datetime.type_name()),
+                &Self::type_name(),
+            )),
+        }
+    }
+}
+
 #[cfg(feature = "serde")]
 struct DatetimeKey;