Generic Associated Types in Database, replacing HasValueRef, HasArgum…

…ents, HasStatement (#2973)

* HasValueRef, HasArguments, HasStatement -> Database GATs

replace the associated types from the generic traits
`HasValueRef<'r>`, `HasArguments<'q>` and `HasStatement<'q>`
with generic associated types in `Database`

* fixup after rebase

---------

Co-authored-by: Austin Bonander <austin.bonander@gmail.com>

sqlx-core/src/any/database.rs

@@ -2,7 +2,7 @@ use crate::any::{
     AnyArgumentBuffer, AnyArguments, AnyColumn, AnyConnection, AnyQueryResult, AnyRow,
     AnyStatement, AnyTransactionManager, AnyTypeInfo, AnyValue, AnyValueRef,
 };
-use crate::database::{Database, HasArguments, HasStatement, HasStatementCache, HasValueRef};
+use crate::database::{Database, HasStatementCache};
 
 /// Opaque database driver. Capable of being used in place of any SQLx database driver. The actual
 /// driver used will be selected at runtime, from the connection url.
@@ -23,29 +23,16 @@ impl Database for Any {
     type TypeInfo = AnyTypeInfo;
 
     type Value = AnyValue;
-    const NAME: &'static str = "Any";
-
-    const URL_SCHEMES: &'static [&'static str] = &[];
-}
-
-impl<'r> HasValueRef<'r> for Any {
-    type Database = Any;
+    type ValueRef<'r> = AnyValueRef<'r>;
 
-    type ValueRef = AnyValueRef<'r>;
-}
+    type Arguments<'q> = AnyArguments<'q>;
+    type ArgumentBuffer<'q> = AnyArgumentBuffer<'q>;
 
-impl<'q> HasStatement<'q> for Any {
-    type Database = Any;
+    type Statement<'q> = AnyStatement<'q>;
 
-    type Statement = AnyStatement<'q>;
-}
-
-impl<'q> HasArguments<'q> for Any {
-    type Database = Any;
-
-    type Arguments = AnyArguments<'q>;
+    const NAME: &'static str = "Any";
 
-    type ArgumentBuffer = AnyArgumentBuffer<'q>;
+    const URL_SCHEMES: &'static [&'static str] = &[];
 }
 
 // This _may_ be true, depending on the selected database

sqlx-core/src/any/row.rs

@@ -1,7 +1,7 @@
 use crate::any::error::mismatched_types;
 use crate::any::{Any, AnyColumn, AnyTypeInfo, AnyTypeInfoKind, AnyValue, AnyValueKind};
 use crate::column::{Column, ColumnIndex};
-use crate::database::{Database, HasValueRef};
+use crate::database::Database;
 use crate::decode::Decode;
 use crate::error::Error;
 use crate::ext::ustr::UStr;
@@ -28,10 +28,7 @@ impl Row for AnyRow {
         &self.columns
     }
 
-    fn try_get_raw<I>(
-        &self,
-        index: I,
-    ) -> Result<<Self::Database as HasValueRef<'_>>::ValueRef, Error>
+    fn try_get_raw<I>(&self, index: I) -> Result<<Self::Database as Database>::ValueRef<'_>, Error>
     where
         I: ColumnIndex<Self>,
     {
@@ -141,7 +138,7 @@ impl AnyRow {
 }
 
 fn decode<'r, DB: Database, T: Decode<'r, DB>>(
-    valueref: <DB as HasValueRef<'r>>::ValueRef,
+    valueref: <DB as Database>::ValueRef<'r>,
 ) -> crate::Result<T> {
     Decode::decode(valueref).map_err(Error::decode)
 }

sqlx-core/src/any/types/blob.rs

@@ -1,5 +1,5 @@
 use crate::any::{Any, AnyTypeInfo, AnyTypeInfoKind, AnyValueKind};
-use crate::database::{HasArguments, HasValueRef};
+use crate::database::Database;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
@@ -15,14 +15,14 @@ impl Type<Any> for [u8] {
 }
 
 impl<'q> Encode<'q, Any> for &'q [u8] {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::Blob((*self).into()));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for &'r [u8] {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         match value.kind {
             AnyValueKind::Blob(Cow::Borrowed(blob)) => Ok(blob),
             // This shouldn't happen in practice, it means the user got an `AnyValueRef`
@@ -42,14 +42,14 @@ impl Type<Any> for Vec<u8> {
 }
 
 impl<'q> Encode<'q, Any> for Vec<u8> {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::Blob(Cow::Owned(self.clone())));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for Vec<u8> {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         match value.kind {
             AnyValueKind::Blob(blob) => Ok(blob.into_owned()),
             other => other.unexpected(),

sqlx-core/src/any/types/bool.rs

@@ -1,5 +1,5 @@
 use crate::any::{Any, AnyTypeInfo, AnyTypeInfoKind, AnyValueKind};
-use crate::database::{HasArguments, HasValueRef};
+use crate::database::Database;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
@@ -14,14 +14,14 @@ impl Type<Any> for bool {
 }
 
 impl<'q> Encode<'q, Any> for bool {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::Bool(*self));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for bool {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         match value.kind {
             AnyValueKind::Bool(b) => Ok(b),
             other => other.unexpected(),

sqlx-core/src/any/types/float.rs

@@ -1,5 +1,5 @@
 use crate::any::{Any, AnyArgumentBuffer, AnyTypeInfo, AnyTypeInfoKind, AnyValueKind, AnyValueRef};
-use crate::database::{HasArguments, HasValueRef};
+use crate::database::Database;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
@@ -38,14 +38,14 @@ impl Type<Any> for f64 {
 }
 
 impl<'q> Encode<'q, Any> for f64 {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::Double(*self));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for f64 {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         match value.kind {
             // Widening is safe
             AnyValueKind::Real(r) => Ok(r as f64),

sqlx-core/src/any/types/int.rs

@@ -1,5 +1,5 @@
 use crate::any::{Any, AnyTypeInfo, AnyTypeInfoKind, AnyValueKind};
-use crate::database::{HasArguments, HasValueRef};
+use crate::database::Database;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
@@ -18,14 +18,14 @@ impl Type<Any> for i16 {
 }
 
 impl<'q> Encode<'q, Any> for i16 {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::SmallInt(*self));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for i16 {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         value.kind.try_integer()
     }
 }
@@ -43,14 +43,14 @@ impl Type<Any> for i32 {
 }
 
 impl<'q> Encode<'q, Any> for i32 {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::Integer(*self));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for i32 {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         value.kind.try_integer()
     }
 }
@@ -68,14 +68,14 @@ impl Type<Any> for i64 {
 }
 
 impl<'q> Encode<'q, Any> for i64 {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::BigInt(*self));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for i64 {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         value.kind.try_integer()
     }
 }

sqlx-core/src/any/types/str.rs

@@ -1,6 +1,6 @@
 use crate::any::types::str;
 use crate::any::{Any, AnyTypeInfo, AnyTypeInfoKind, AnyValueKind};
-use crate::database::{HasArguments, HasValueRef};
+use crate::database::Database;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
@@ -16,21 +16,21 @@ impl Type<Any> for str {
 }
 
 impl<'a> Encode<'a, Any> for &'a str {
-    fn encode(self, buf: &mut <Any as HasArguments<'a>>::ArgumentBuffer) -> IsNull
+    fn encode(self, buf: &mut <Any as Database>::ArgumentBuffer<'a>) -> IsNull
     where
         Self: Sized,
     {
         buf.0.push(AnyValueKind::Text(self.into()));
         IsNull::No
     }
 
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'a>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'a>) -> IsNull {
         (*self).encode(buf)
     }
 }
 
 impl<'a> Decode<'a, Any> for &'a str {
-    fn decode(value: <Any as HasValueRef<'a>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'a>) -> Result<Self, BoxDynError> {
         match value.kind {
             AnyValueKind::Text(Cow::Borrowed(text)) => Ok(text),
             // This shouldn't happen in practice, it means the user got an `AnyValueRef`
@@ -50,14 +50,14 @@ impl Type<Any> for String {
 }
 
 impl<'q> Encode<'q, Any> for String {
-    fn encode_by_ref(&self, buf: &mut <Any as HasArguments<'q>>::ArgumentBuffer) -> IsNull {
+    fn encode_by_ref(&self, buf: &mut <Any as Database>::ArgumentBuffer<'q>) -> IsNull {
         buf.0.push(AnyValueKind::Text(Cow::Owned(self.clone())));
         IsNull::No
     }
 }
 
 impl<'r> Decode<'r, Any> for String {
-    fn decode(value: <Any as HasValueRef<'r>>::ValueRef) -> Result<Self, BoxDynError> {
+    fn decode(value: <Any as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
         match value.kind {
             AnyValueKind::Text(text) => Ok(text.into_owned()),
             other => other.unexpected(),

sqlx-core/src/any/value.rs

@@ -1,7 +1,7 @@
 use std::borrow::Cow;
 
 use crate::any::{Any, AnyTypeInfo, AnyTypeInfoKind};
-use crate::database::{Database, HasValueRef};
+use crate::database::Database;
 use crate::error::BoxDynError;
 use crate::types::Type;
 use crate::value::{Value, ValueRef};
@@ -71,7 +71,7 @@ pub struct AnyValueRef<'a> {
 impl Value for AnyValue {
     type Database = Any;
 
-    fn as_ref(&self) -> <Self::Database as HasValueRef<'_>>::ValueRef {
+    fn as_ref(&self) -> <Self::Database as Database>::ValueRef<'_> {
         AnyValueRef {
             kind: match &self.kind {
                 AnyValueKind::Null => AnyValueKind::Null,

sqlx-core/src/arguments.rs

@@ -1,6 +1,6 @@
 //! Types and traits for passing arguments to SQL queries.
 
-use crate::database::{Database, HasArguments};
+use crate::database::Database;
 use crate::encode::Encode;
 use crate::types::Type;
 use std::fmt::{self, Write};
@@ -23,8 +23,8 @@ pub trait Arguments<'q>: Send + Sized + Default {
     }
 }
 
-pub trait IntoArguments<'q, DB: HasArguments<'q>>: Sized + Send {
-    fn into_arguments(self) -> <DB as HasArguments<'q>>::Arguments;
+pub trait IntoArguments<'q, DB: Database>: Sized + Send {
+    fn into_arguments(self) -> <DB as Database>::Arguments<'q>;
 }
 
 // NOTE: required due to lack of lazy normalization
@@ -45,10 +45,10 @@ macro_rules! impl_into_arguments_for_arguments {
 }
 
 /// used by the query macros to prevent supernumerary `.bind()` calls
-pub struct ImmutableArguments<'q, DB: HasArguments<'q>>(pub <DB as HasArguments<'q>>::Arguments);
+pub struct ImmutableArguments<'q, DB: Database>(pub <DB as Database>::Arguments<'q>);
 
-impl<'q, DB: HasArguments<'q>> IntoArguments<'q, DB> for ImmutableArguments<'q, DB> {
-    fn into_arguments(self) -> <DB as HasArguments<'q>>::Arguments {
+impl<'q, DB: Database> IntoArguments<'q, DB> for ImmutableArguments<'q, DB> {
+    fn into_arguments(self) -> <DB as Database>::Arguments<'q> {
         self.0
     }
 }