decode: use HasRawValue

sqlx-core/src/database.rs

@@ -13,8 +13,8 @@ use crate::types::TypeInfo;
 pub trait Database
 where
     Self: Sized + Send + 'static,
-    Self: for<'a> HasRow<'a, Database = Self>,
-    Self: for<'a> HasRawValue<'a>,
+    Self: for<'c> HasRow<'c, Database = Self>,
+    Self: for<'c> HasRawValue<'c>,
     Self: for<'c, 'q> HasCursor<'c, 'q, Database = Self>,
 {
     /// The concrete `Connection` implementation for this database.
@@ -30,7 +30,7 @@ where
     type TableId: Display + Clone;
 }
 
-pub trait HasRawValue<'a> {
+pub trait HasRawValue<'c> {
     type RawValue;
 }
 
@@ -40,8 +40,8 @@ pub trait HasCursor<'c, 'q> {
     type Cursor: Cursor<'c, 'q, Database = Self::Database>;
 }
 
-pub trait HasRow<'a> {
+pub trait HasRow<'c> {
     type Database: Database;
 
-    type Row: Row<'a, Database = Self::Database>;
+    type Row: Row<'c, Database = Self::Database>;
 }

sqlx-core/src/decode.rs

@@ -3,46 +3,15 @@
 use std::error::Error as StdError;
 use std::fmt::{self, Display};
 
-use crate::database::Database;
-use crate::types::Type;
+use crate::database::{Database, HasRawValue};
 
 /// Decode a single value from the database.
 pub trait Decode<'de, DB>
 where
     Self: Sized,
-    DB: Database,
+    DB: HasRawValue<'de>,
 {
-    fn decode(raw: &'de [u8]) -> crate::Result<Self>;
-
-    /// Creates a new value of this type from a `NULL` SQL value.
-    ///
-    /// The default implementation returns [DecodeError::UnexpectedNull].
-    fn decode_null() -> crate::Result<Self> {
-        Err(crate::Error::Decode(UnexpectedNullError.into()))
-    }
-
-    fn decode_nullable(raw: Option<&'de [u8]>) -> crate::Result<Self> {
-        if let Some(raw) = raw {
-            Self::decode(raw)
-        } else {
-            Self::decode_null()
-        }
-    }
-}
-
-impl<'de, T, DB> Decode<'de, DB> for Option<T>
-where
-    DB: Database,
-    T: Type<DB>,
-    T: Decode<'de, DB>,
-{
-    fn decode(buf: &'de [u8]) -> crate::Result<Self> {
-        T::decode(buf).map(Some)
-    }
-
-    fn decode_null() -> crate::Result<Self> {
-        Ok(None)
-    }
+    fn decode(raw: DB::RawValue) -> crate::Result<Self>;
 }
 
 /// An unexpected `NULL` was encountered during decoding.

sqlx-core/src/row.rs

@@ -1,6 +1,6 @@
 //! Contains the Row and FromRow traits.
 
-use crate::database::Database;
+use crate::database::{Database, HasRawValue};
 use crate::decode::Decode;
 use crate::types::Type;
 
@@ -38,10 +38,13 @@ pub trait Row<'c>: Unpin + Send {
         I: ColumnIndex<'c, Self>,
         T: Decode<'c, Self::Database>,
     {
-        Ok(Decode::decode_nullable(self.try_get_raw(index)?)?)
+        Ok(Decode::decode(self.try_get_raw(index)?)?)
     }
 
-    fn try_get_raw<'i, I>(&'c self, index: I) -> crate::Result<Option<&'c [u8]>>
+    fn try_get_raw<'i, I>(
+        &'c self,
+        index: I,
+    ) -> crate::Result<<Self::Database as HasRawValue<'c>>::RawValue>
     where
         I: ColumnIndex<'c, Self> + 'i;
 }