RUST-765 Depend on futures subcrates instead of futures (C-STABLE)

Author: patrickfreed

Cargo.toml

@@ -37,7 +37,10 @@ bitflags = "1.1.0"
 bson = { git = "https://github.com/mongodb/bson-rust" }
 chrono = "0.4.7"
 derivative = "2.1.1"
-futures = "0.3.5"
+futures-core = "0.3.14"
+futures-io = "0.3.14"
+futures-util = { version = "0.3.14", features = ["io"] }
+futures-executor = "0.3.14"
 hex = "0.4.0"
 hmac = "0.10.1"
 lazy_static = "1.4.0"
@@ -110,6 +113,7 @@ features = ["v4"]
 approx = "0.4.0"
 derive_more = "0.99.13"
 function_name = "0.2.0"
+futures = "0.3"
 pretty_assertions = "0.7.1"
 serde_json = "1.0.64"
 semver = "0.11.0"

src/bson_util/async_encoding.rs

@@ -1,4 +1,5 @@
-use futures::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
+use futures_io::{AsyncRead, AsyncWrite};
+use futures_util::{AsyncReadExt, AsyncWriteExt};
 
 use crate::{
     bson::Document,

src/cmap/conn/wire/message.rs

@@ -1,5 +1,6 @@
 use bitflags::bitflags;
-use futures::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
+use futures_io::{AsyncRead, AsyncWrite};
+use futures_util::{AsyncReadExt, AsyncWriteExt};
 
 use super::{
     header::{Header, OpCode},

src/cmap/conn/wire/util.rs

@@ -4,7 +4,8 @@ use std::{
     task::{Context, Poll},
 };
 
-use futures::io::{self, AsyncRead, AsyncWrite, AsyncWriteExt};
+use futures_io::{self, AsyncRead, AsyncWrite};
+use futures_util::AsyncWriteExt;
 use lazy_static::lazy_static;
 
 use crate::error::Result;
@@ -32,7 +33,7 @@ pub(super) async fn write_cstring<W: AsyncWrite + Unpin>(
     Ok(())
 }
 
-/// A wrapper around `futures::io::AsyncRead` that keeps track of the number of bytes it has read.
+/// A wrapper around `futures_io::AsyncRead` that keeps track of the number of bytes it has read.
 pub(super) struct CountReader<'a, R: AsyncRead + Unpin + Send + 'a> {
     reader: &'a mut R,
     bytes_read: usize,
@@ -58,7 +59,7 @@ impl<'a, R: AsyncRead + Unpin + Send + 'a> AsyncRead for CountReader<'a, R> {
         mut self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut [u8],
-    ) -> Poll<io::Result<usize>> {
+    ) -> Poll<futures_io::Result<usize>> {
         let result = Pin::new(&mut self.reader).poll_read(cx, buf);
 
         if let Poll::Ready(Ok(count)) = result {

src/coll/mod.rs

@@ -3,7 +3,7 @@ pub mod options;
 
 use std::{borrow::Borrow, fmt, fmt::Debug, sync::Arc};
 
-use futures::StreamExt;
+use futures_util::stream::StreamExt;
 use serde::{
     de::{DeserializeOwned, Error},
     Deserialize,

src/cursor/common.rs

@@ -6,7 +6,7 @@ use std::{
 };
 
 use derivative::Derivative;
-use futures::{Future, Stream};
+use futures_core::{Future, Stream};
 
 use crate::{
     bson::Document,

src/cursor/mod.rs

@@ -6,7 +6,7 @@ use std::{
     task::{Context, Poll},
 };
 
-use futures::{future::BoxFuture, Stream};
+use futures_core::{future::BoxFuture, Stream};
 use serde::de::DeserializeOwned;
 
 use crate::{

src/cursor/session.rs

@@ -4,7 +4,7 @@ use std::{
     task::{Context, Poll},
 };
 
-use futures::{future::BoxFuture, Stream};
+use futures_core::{future::BoxFuture, Stream};
 use serde::de::DeserializeOwned;
 
 use super::common::{CursorInformation, GenericCursor, GetMoreProvider, GetMoreProviderResult};

src/db/mod.rs

@@ -2,7 +2,7 @@ pub mod options;
 
 use std::{fmt::Debug, sync::Arc};
 
-use futures::stream::TryStreamExt;
+use futures_util::stream::TryStreamExt;
 use serde::{de::DeserializeOwned, Serialize};
 
 use crate::{
@@ -235,8 +235,8 @@ impl Database {
     ) -> Result<Vec<String>> {
         cursor
             .and_then(|doc| match doc.get("name").and_then(Bson::as_str) {
-                Some(name) => futures::future::ok(name.into()),
-                None => futures::future::err(
+                Some(name) => futures_util::future::ok(name.into()),
+                None => futures_util::future::err(
                     ErrorKind::InvalidResponse {
                         message: "Expected name field in server response, but there was none."
                             .to_string(),

src/runtime/async_read_ext.rs

@@ -1,11 +1,11 @@
 use async_trait::async_trait;
-use futures::io::AsyncRead;
+use futures_io::AsyncRead;
 
 use crate::error::Result;
 
 /// Trait providing helpers that read various integer types in little-endian order.
 #[async_trait]
-pub(crate) trait AsyncLittleEndianRead: Unpin + futures::io::AsyncReadExt {
+pub(crate) trait AsyncLittleEndianRead: Unpin + futures_util::AsyncReadExt {
     /// Read an `i32` in little-endian order.
     async fn read_i32(&mut self) -> Result<i32> {
         let mut buf: [u8; 4] = [0; 4];