Add FromField DiffTime and FromField TimeOfDay

lib/Database/PostgreSQL/Opium/FromField.hs

@@ -16,7 +16,13 @@ import Data.ByteString (ByteString)
 import Data.Functor (($>))
 import Data.Int (Int32)
 import Data.Proxy (Proxy (..))
-import Data.Time (Day (..))
+import Data.Time
+  ( Day (..)
+  , DiffTime
+  , TimeOfDay
+  , picosecondsToDiffTime
+  , timeToTimeOfDay
+  )
 import Data.Text (Text)
 import Data.Word (Word32, Word64)
 import Database.PostgreSQL.LibPQ (Oid)
@@ -125,6 +131,23 @@ instance FromField Day where
     where
       fromJulianDay x = ModifiedJulianDay $ x + 51544
 
+-- | See https://www.postgresql.org/docs/current/datatype-datetime.html.
+-- Binary format: https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/adt/date.c;h=ae0f24de2c3c54eb6d0405cdb212597c2407238e;hb=HEAD#l1542.
+-- Accepts @time@.
+instance FromField DiffTime where
+  validOid Proxy = Oid.time
+  parseField = microsecondsToDiffTime <$> intParser
+    where
+      microsecondsToDiffTime :: Integer -> DiffTime
+      microsecondsToDiffTime ms = picosecondsToDiffTime $ ms * 1000000
+
+-- | See https://www.postgresql.org/docs/current/datatype-datetime.html.
+-- Binary format: https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/adt/date.c;h=ae0f24de2c3c54eb6d0405cdb212597c2407238e;hb=HEAD#l1542.
+-- Accepts @time@.
+instance FromField TimeOfDay where
+  validOid Proxy = Oid.time
+  parseField = timeToTimeOfDay <$> parseField @DiffTime
+
 newtype RawField = RawField ByteString
   deriving (Eq, Show)
 

lib/Database/PostgreSQL/Opium/Oid.hs

@@ -52,3 +52,7 @@ boolean = eq $ Oid 16
 -- | Single days/dates.
 date :: Oid -> Bool
 date = eq $ Oid 1082
+
+-- | Time of day.
+time :: Oid -> Bool
+time = eq $ Oid 1083