Replace async_trait with native async fns

Author: gahag-cw

bb8/Cargo.toml

@@ -10,7 +10,6 @@ workspace = ".."
 readme = "../README.md"
 
 [dependencies]
-async-trait = "0.1"
 futures-util = { version = "0.3.2", default-features = false, features = ["alloc"] }
 parking_lot = { version = "0.12", optional = true }
 tokio = { version = "1.0", features = ["rt", "sync", "time"] }

bb8/src/api.rs

@@ -1,12 +1,12 @@
 use std::borrow::Cow;
 use std::error;
 use std::fmt;
+use std::future::Future;
 use std::marker::PhantomData;
 use std::ops::{Deref, DerefMut};
+use std::pin::Pin;
 use std::time::Duration;
 
-use async_trait::async_trait;
-
 use crate::inner::PoolInner;
 use crate::internals::Conn;
 
@@ -381,23 +381,24 @@ impl<M: ManageConnection> Builder<M> {
 }
 
 /// A trait which provides connection-specific functionality.
-#[async_trait]
 pub trait ManageConnection: Sized + Send + Sync + 'static {
  /// The connection type this manager deals with.
  type Connection: Send + 'static;
  /// The error type returned by `Connection`s.
  type Error: fmt::Debug + Send + 'static;
 
  /// Attempts to create a new connection.
- async fn connect(&self) -> Result<Self::Connection, Self::Error>;
+ fn connect(&self) -> impl Future<Output = Result<Self::Connection, Self::Error>> + Send;
  /// Determines if the connection is still connected to the database.
- async fn is_valid(&self, conn: &mut Self::Connection) -> Result<(), Self::Error>;
+ fn is_valid(
+ &self,
+ conn: &mut Self::Connection,
+ ) -> impl Future<Output = Result<(), Self::Error>> + Send;
  /// Synchronously determine if the connection is no longer usable, if possible.
  fn has_broken(&self, conn: &mut Self::Connection) -> bool;
 }
 
 /// A trait which provides functionality to initialize a connection
-#[async_trait]
 pub trait CustomizeConnection<C: Send + 'static, E: 'static>:
  fmt::Debug + Send + Sync + 'static
 {
@@ -406,8 +407,11 @@ pub trait CustomizeConnection<C: Send + 'static, E: 'static>:
  ///
  /// The default implementation simply returns `Ok(())`. If this method returns an
  /// error, it will be forwarded to the configured error sink.
- async fn on_acquire(&self, _connection: &mut C) -> Result<(), E> {
- Ok(())
+ fn on_acquire<'a>(
+ &'a self,
+ _connection: &'a mut C,
+ ) -> Pin<Box<dyn Future<Output = Result<(), E>> + Send + 'a>> {
+ Box::pin(async { Ok(()) })
  }
 }
 

bb8/tests/test.rs

@@ -9,7 +9,6 @@ use std::task::Poll;
 use std::time::Duration;
 use std::{error, fmt};
 
-use async_trait::async_trait;
 use futures_util::future::{err, lazy, ok, pending, ready, try_join_all, FutureExt};
 use futures_util::stream::{FuturesUnordered, TryStreamExt};
 use tokio::sync::oneshot;
@@ -43,7 +42,6 @@ impl<C> OkManager<C> {
  }
 }
 
-#[async_trait]
 impl<C> ManageConnection for OkManager<C>
 where
  C: Default + Send + Sync + 'static,
@@ -78,7 +76,6 @@ impl<C> NthConnectionFailManager<C> {
  }
 }
 
-#[async_trait]
 impl<C> ManageConnection for NthConnectionFailManager<C>
 where
  C: Default + Send + Sync + 'static,
@@ -214,7 +211,6 @@ struct BrokenConnectionManager<C> {
  _c: PhantomData<C>,
 }
 
-#[async_trait]
 impl<C: Default + Send + Sync + 'static> ManageConnection for BrokenConnectionManager<C> {
  type Connection = C;
  type Error = Error;
@@ -380,7 +376,6 @@ async fn test_now_invalid() {
 
  struct Handler;
 
- #[async_trait]
  impl ManageConnection for Handler {
  type Connection = FakeConnection;
  type Error = Error;
@@ -689,7 +684,6 @@ async fn test_conns_drop_on_pool_drop() {
 
  struct Handler;
 
- #[async_trait]
  impl ManageConnection for Handler {
  type Connection = Connection;
  type Error = Error;
@@ -741,7 +735,6 @@ async fn test_retry() {
  struct Connection;
  struct Handler;
 
- #[async_trait]
  impl ManageConnection for Handler {
  type Connection = Connection;
  type Error = Error;
@@ -787,7 +780,6 @@ async fn test_conn_fail_once() {
  }
  }
 
- #[async_trait]
  impl ManageConnection for Handler {
  type Connection = Connection;
  type Error = Error;
@@ -912,11 +904,15 @@ async fn test_customize_connection_acquire() {
  count: AtomicUsize,
  }
 
- #[async_trait]
  impl<E: 'static> CustomizeConnection<Connection, E> for CountingCustomizer {
- async fn on_acquire(&self, connection: &mut Connection) -> Result<(), E> {
- connection.custom_field = 1 + self.count.fetch_add(1, Ordering::SeqCst);
- Ok(())
+ fn on_acquire<'a>(
+ &'a self,
+ connection: &'a mut Connection,
+ ) -> Pin<Box<dyn Future<Output = Result<(), E>> + Send + 'a>> {
+ Box::pin(async move {
+ connection.custom_field = 1 + self.count.fetch_add(1, Ordering::SeqCst);
+ Ok(())
+ })
  }
  }
 
@@ -952,7 +948,6 @@ async fn test_broken_connections_dont_starve_pool() {
  #[derive(Debug)]
  struct Connection;
 
- #[async_trait::async_trait]
  impl bb8::ManageConnection for ConnectionManager {
  type Connection = Connection;
  type Error = Infallible;

postgres/Cargo.toml

@@ -19,7 +19,6 @@ repository = "https://github.com/djc/bb8"
 "with-time-0_3" = ["tokio-postgres/with-time-0_3"]
 
 [dependencies]
-async-trait = "0.1"
 bb8 = { version = "0.8", path = "../bb8" }
 tokio = { version = "1.0.0", features = ["rt"] }
 tokio-postgres = "0.7"

postgres/examples/custom_state.rs

@@ -1,8 +1,9 @@
 use std::collections::BTreeMap;
+use std::future::Future;
 use std::ops::Deref;
+use std::pin::Pin;
 use std::str::FromStr;
 
-use async_trait::async_trait;
 use bb8::{CustomizeConnection, Pool};
 use bb8_postgres::PostgresConnectionManager;
 use tokio_postgres::config::Config;
@@ -43,16 +44,20 @@ async fn main() {
 #[derive(Debug)]
 struct Customizer;
 
-#[async_trait]
 impl CustomizeConnection<CustomPostgresConnection, Error> for Customizer {
- async fn on_acquire(&self, conn: &mut CustomPostgresConnection) -> Result<(), Error> {
- conn.custom_state
- .insert(QueryName::BasicSelect, conn.prepare("SELECT 1").await?);
-
- conn.custom_state
- .insert(QueryName::Addition, conn.prepare("SELECT 1 + 1 + 1").await?);
-
- Ok(())
+ fn on_acquire<'a>(
+ &'a self,
+ conn: &'a mut CustomPostgresConnection,
+ ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'a>> {
+ Box::pin(async {
+ conn.custom_state
+ .insert(QueryName::BasicSelect, conn.prepare("SELECT 1").await?);
+
+ conn.custom_state
+ .insert(QueryName::Addition, conn.prepare("SELECT 1 + 1 + 1").await?);
+
+ Ok(())
+ })
  }
 }
 
@@ -96,7 +101,6 @@ where
  }
 }
 
-#[async_trait]
 impl<Tls> bb8::ManageConnection for CustomPostgresConnectionManager<Tls>
 where
  Tls: MakeTlsConnect<Socket> + Clone + Send + Sync + 'static,

postgres/src/lib.rs

@@ -4,7 +4,6 @@
 pub use bb8;
 pub use tokio_postgres;
 
-use async_trait::async_trait;
 use tokio_postgres::config::Config;
 use tokio_postgres::tls::{MakeTlsConnect, TlsConnect};
 use tokio_postgres::{Client, Error, Socket};
@@ -45,7 +44,6 @@ where
  }
 }
 
-#[async_trait]
 impl<Tls> bb8::ManageConnection for PostgresConnectionManager<Tls>
 where
  Tls: MakeTlsConnect<Socket> + Clone + Send + Sync + 'static,

redis/Cargo.toml

@@ -8,7 +8,6 @@ license = "MIT"
 repository = "https://github.com/djc/bb8"
 
 [dependencies]
-async-trait = "0.1"
 bb8 = { version = "0.8", path = "../bb8" }
 redis = { version = "0.27", default-features = false, features = ["tokio-comp"] }
 

redis/src/lib.rs

@@ -38,7 +38,6 @@
 pub use bb8;
 pub use redis;
 
-use async_trait::async_trait;
 use redis::{aio::MultiplexedConnection, ErrorKind};
 use redis::{Client, IntoConnectionInfo, RedisError};
 
@@ -58,7 +57,6 @@ impl RedisConnectionManager {
  }
 }
 
-#[async_trait]
 impl bb8::ManageConnection for RedisConnectionManager {
  type Connection = MultiplexedConnection;
  type Error = RedisError;