Replace some futures_util APIs with std variants (#3721)

Author: paolobarbolini

sqlx-core/src/io/write_and_flush.rs

@@ -1,10 +1,9 @@
 use crate::error::Error;
-use futures_core::Future;
-use futures_util::ready;
 use sqlx_rt::AsyncWrite;
+use std::future::Future;
 use std::io::{BufRead, Cursor};
 use std::pin::Pin;
-use std::task::{Context, Poll};
+use std::task::{ready, Context, Poll};
 
 // Atomic operation that writes the full buffer to the stream, flushes the stream, and then
 // clears the buffer (even if either of the two previous operations failed).

sqlx-core/src/net/socket/mod.rs

@@ -2,10 +2,9 @@ use std::future::Future;
 use std::io;
 use std::path::Path;
 use std::pin::Pin;
-use std::task::{Context, Poll};
+use std::task::{ready, Context, Poll};
 
 use bytes::BufMut;
-use futures_core::ready;
 
 pub use buffered::{BufferedSocket, WriteBuffer};
 

sqlx-core/src/net/tls/util.rs

@@ -1,9 +1,8 @@
 use crate::net::Socket;
 
 use std::io::{self, Read, Write};
-use std::task::{Context, Poll};
+use std::task::{ready, Context, Poll};
 
-use futures_core::ready;
 use futures_util::future;
 
 pub struct StdSocket<S> {

sqlx-core/src/pool/inner.rs

@@ -10,6 +10,7 @@ use crate::sync::{AsyncSemaphore, AsyncSemaphoreReleaser};
 
 use std::cmp;
 use std::future::Future;
+use std::pin::pin;
 use std::sync::atomic::{AtomicBool, AtomicU32, AtomicUsize, Ordering};
 use std::sync::{Arc, RwLock};
 use std::task::Poll;
@@ -130,19 +131,12 @@ impl<DB: Database> PoolInner<DB> {
             // This is just going to cause unnecessary churn in `acquire()`.
             .filter(|_| self.size() < self.options.max_connections);
 
-        let acquire_self = self.semaphore.acquire(1).fuse();
-        let mut close_event = self.close_event();
+        let mut acquire_self = pin!(self.semaphore.acquire(1).fuse());
+        let mut close_event = pin!(self.close_event());
 
         if let Some(parent) = parent {
-            let acquire_parent = parent.0.semaphore.acquire(1);
-            let parent_close_event = parent.0.close_event();
-
-            futures_util::pin_mut!(
-                acquire_parent,
-                acquire_self,
-                close_event,
-                parent_close_event
-            );
+            let mut acquire_parent = pin!(parent.0.semaphore.acquire(1));
+            let mut parent_close_event = pin!(parent.0.close_event());
 
             let mut poll_parent = false;
 

sqlx-core/src/pool/mod.rs

@@ -56,7 +56,7 @@
 
 use std::fmt;
 use std::future::Future;
-use std::pin::Pin;
+use std::pin::{pin, Pin};
 use std::sync::Arc;
 use std::task::{Context, Poll};
 use std::time::{Duration, Instant};
@@ -565,11 +565,11 @@ impl CloseEvent {
             .await
             .map_or(Ok(()), |_| Err(Error::PoolClosed))?;
 
-        futures_util::pin_mut!(fut);
+        let mut fut = pin!(fut);
 
         // I find that this is clearer in intent than `futures_util::future::select()`
         // or `futures_util::select_biased!{}` (which isn't enabled anyway).
-        futures_util::future::poll_fn(|cx| {
+        std::future::poll_fn(|cx| {
             // Poll `fut` first as the wakeup event is more likely for it than `self`.
             if let Poll::Ready(ret) = fut.as_mut().poll(cx) {
                 return Poll::Ready(Ok(ret));

sqlx-mysql/src/any.rs

@@ -16,7 +16,7 @@ use sqlx_core::database::Database;
 use sqlx_core::describe::Describe;
 use sqlx_core::executor::Executor;
 use sqlx_core::transaction::TransactionManager;
-use std::future;
+use std::{future, pin::pin};
 
 sqlx_core::declare_driver_with_optional_migrate!(DRIVER = MySql);
 
@@ -113,8 +113,7 @@ impl AnyConnectionBackend for MySqlConnection {
 
         Box::pin(async move {
             let arguments = arguments?;
-            let stream = self.run(query, arguments, persistent).await?;
-            futures_util::pin_mut!(stream);
+            let mut stream = pin!(self.run(query, arguments, persistent).await?);
 
             while let Some(result) = stream.try_next().await? {
                 if let Either::Right(row) = result {

sqlx-mysql/src/connection/executor.rs

@@ -21,8 +21,8 @@ use either::Either;
 use futures_core::future::BoxFuture;
 use futures_core::stream::BoxStream;
 use futures_core::Stream;
-use futures_util::{pin_mut, TryStreamExt};
-use std::{borrow::Cow, sync::Arc};
+use futures_util::TryStreamExt;
+use std::{borrow::Cow, pin::pin, sync::Arc};
 
 impl MySqlConnection {
     async fn prepare_statement<'c>(
@@ -263,8 +263,7 @@ impl<'c> Executor<'c> for &'c mut MySqlConnection {
 
         Box::pin(try_stream! {
             let arguments = arguments?;
-            let s = self.run(sql, arguments, persistent).await?;
-            pin_mut!(s);
+            let mut s = pin!(self.run(sql, arguments, persistent).await?);
 
             while let Some(v) = s.try_next().await? {
                 r#yield!(v);

sqlx-postgres/src/any.rs

@@ -5,7 +5,7 @@ use crate::{
 use futures_core::future::BoxFuture;
 use futures_core::stream::BoxStream;
 use futures_util::{stream, StreamExt, TryFutureExt, TryStreamExt};
-use std::future;
+use std::{future, pin::pin};
 
 use sqlx_core::any::{
     Any, AnyArguments, AnyColumn, AnyConnectOptions, AnyConnectionBackend, AnyQueryResult, AnyRow,
@@ -115,8 +115,7 @@ impl AnyConnectionBackend for PgConnection {
 
         Box::pin(async move {
             let arguments = arguments?;
-            let stream = self.run(query, arguments, 1, persistent, None).await?;
-            futures_util::pin_mut!(stream);
+            let mut stream = pin!(self.run(query, arguments, 1, persistent, None).await?);
 
             if let Some(Either::Right(row)) = stream.try_next().await? {
                 return Ok(Some(AnyRow::try_from(&row)?));

sqlx-postgres/src/connection/executor.rs

@@ -15,10 +15,10 @@ use crate::{
 use futures_core::future::BoxFuture;
 use futures_core::stream::BoxStream;
 use futures_core::Stream;
-use futures_util::{pin_mut, TryStreamExt};
+use futures_util::TryStreamExt;
 use sqlx_core::arguments::Arguments;
 use sqlx_core::Either;
-use std::{borrow::Cow, sync::Arc};
+use std::{borrow::Cow, pin::pin, sync::Arc};
 
 async fn prepare(
     conn: &mut PgConnection,
@@ -393,8 +393,7 @@ impl<'c> Executor<'c> for &'c mut PgConnection {
 
         Box::pin(try_stream! {
             let arguments = arguments?;
-            let s = self.run(sql, arguments, 0, persistent, metadata).await?;
-            pin_mut!(s);
+            let mut s = pin!(self.run(sql, arguments, 0, persistent, metadata).await?);
 
             while let Some(v) = s.try_next().await? {
                 r#yield!(v);
@@ -420,8 +419,7 @@ impl<'c> Executor<'c> for &'c mut PgConnection {
 
         Box::pin(async move {
             let arguments = arguments?;
-            let s = self.run(sql, arguments, 1, persistent, metadata).await?;
-            pin_mut!(s);
+            let mut s = pin!(self.run(sql, arguments, 1, persistent, metadata).await?);
 
             // With deferred constraints we need to check all responses as we
             // could get a OK response (with uncommitted data), only to get an

sqlx-sqlite/src/any.rs

@@ -17,6 +17,7 @@ use sqlx_core::database::Database;
 use sqlx_core::describe::Describe;
 use sqlx_core::executor::Executor;
 use sqlx_core::transaction::TransactionManager;
+use std::pin::pin;
 
 sqlx_core::declare_driver_with_optional_migrate!(DRIVER = Sqlite);
 
@@ -105,12 +106,12 @@ impl AnyConnectionBackend for SqliteConnection {
         let args = arguments.map(map_arguments);
 
         Box::pin(async move {
-            let stream = self
-                .worker
-                .execute(query, args, self.row_channel_size, persistent, Some(1))
-                .map_ok(flume::Receiver::into_stream)
-                .await?;
-            futures_util::pin_mut!(stream);
+            let mut stream = pin!(
+                self.worker
+                    .execute(query, args, self.row_channel_size, persistent, Some(1))
+                    .map_ok(flume::Receiver::into_stream)
+                    .await?
+            );
 
             if let Some(Either::Right(row)) = stream.try_next().await? {
                 return Ok(Some(AnyRow::try_from(&row)?));