postgres: create chrono_truncate_nanos and time_truncate_nanos

sqlx-core/src/postgres/types/interval.rs

@@ -66,6 +66,9 @@ impl Encode<Postgres> for PgInterval {
 impl TryFrom<PgInterval> for chrono::Duration {
     type Error = crate::Error;
 
+    /// Convert a `PgInterval` to a `chrono::Duration`
+    ///
+    /// The convertion will fail if any of the fields `days` or `months` is different to 0.
     fn try_from(value: PgInterval) -> crate::Result<chrono::Duration> {
         match (value.days, value.months) {
             (0, 0) => Ok(Self::microseconds(value.microseconds)),
@@ -80,6 +83,14 @@ impl TryFrom<PgInterval> for chrono::Duration {
 impl TryFrom<chrono::Duration> for PgInterval {
     type Error = crate::Error;
 
+    /// Convert a `chrono::Duration to a `PgInterval`
+    ///
+    /// The convertion will fail if there is a loss of precision with the nanoseconds. To do a
+    /// lossy conversion use `PgInterval::chrono_truncate_nanos()`.
+    ///
+    /// # Panics
+    ///
+    /// The convertion panics if there is an overflow with the microseconds or nanoseconds
     fn try_from(value: chrono::Duration) -> crate::Result<Self> {
         let microseconds = value.num_microseconds().expect("Microseconds overflow");
         match value
@@ -100,10 +111,60 @@ impl TryFrom<chrono::Duration> for PgInterval {
     }
 }
 
+impl PgInterval {
+    /// Convert a `time::Duration` object to a `PgInterval` object but truncate the remaining nanoseconds.
+    /// # Panics
+    ///
+    /// Panics if there is an overflow retrieving the microseconds
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use sqlx_core::postgres::types::PgInterval;
+    /// let interval = PgInterval::time_truncate_nanos(time::Duration::seconds(3_600));
+    /// assert_eq!(interval, PgInterval { months: 0, days: 0, microseconds: 3_600_000_000 });
+    /// ```
+    #[cfg(feature = "time")]
+    pub fn time_truncate_nanos(value: time::Duration) -> Self {
+        let microseconds =
+            i64::try_from(value.whole_microseconds()).expect("Microseconds overflow");
+        Self {
+            months: 0,
+            days: 0,
+            microseconds,
+        }
+    }
+
+    /// Convert a `chrono::Duration` object to a `PgInterval` object but truncates the remaining nanoseconds.
+    /// # Panics
+    ///
+    /// Panics if there is an overflow retrieving the microseconds
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use sqlx_core::postgres::types::PgInterval;
+    /// let interval = PgInterval::chrono_truncate_nanos(chrono::Duration::seconds(3_600));
+    /// assert_eq!(interval, PgInterval { months: 0, days: 0, microseconds: 3_600_000_000 });
+    /// ```
+    #[cfg(feature = "chrono")]
+    pub fn chrono_truncate_nanos(value: chrono::Duration) -> Self {
+        let microseconds = value.num_microseconds().expect("Microseconds overflow");
+        Self {
+            months: 0,
+            days: 0,
+            microseconds,
+        }
+    }
+}
+
 #[cfg(feature = "time")]
 impl TryFrom<PgInterval> for time::Duration {
     type Error = crate::Error;
 
+    /// Convert a `PgInterval` to a `time::Duration`
+    ///
+    /// The convertion will fail if any of the fields `days` or `months` is different to 0.
     fn try_from(value: PgInterval) -> crate::Result<Self> {
         match (value.days, value.months) {
             (0, 0) => Ok(Self::microseconds(value.microseconds)),
@@ -118,6 +179,14 @@ impl TryFrom<PgInterval> for time::Duration {
 impl TryFrom<time::Duration> for PgInterval {
     type Error = crate::Error;
 
+    /// Convert a `time::Duration to a `PgInterval`
+    ///
+    /// The convertion will fail if there is a loss of precision with the nanoseconds. To do a
+    /// lossy conversion use `PgInterval::time_truncate_nanos()`.
+    ///
+    /// # Panics
+    ///
+    /// The convertion panics if there is an overflow with the microseconds
     fn try_from(value: time::Duration) -> crate::Result<Self> {
         let microseconds =
             i64::try_from(value.whole_microseconds()).expect("Microseconds overflow");