From bf092b3d9e1765d9bb31225d33d51451711afa7c Mon Sep 17 00:00:00 2001
From: Stepan Koltsov <stepan.koltsov@gmail.com>
Date: Sat, 10 Nov 2018 01:20:03 +0000
Subject: [PATCH] Move AtomicWaker to futures-core

... so `AtomicWaker` could be used inside `futures-channel`.

`AtomicWaker` is still accessible to users only from `futures-util`.
---
 futures-core/Cargo.toml                                |  6 ++++++
 futures-core/src/lib.rs                                |  1 +
 .../src/task/__internal}/atomic_waker.rs               |  7 ++++---
 futures-core/src/task/__internal/mod.rs                | 10 ++++++++++
 futures-core/src/task/mod.rs                           |  2 ++
 futures-util/src/task/mod.rs                           |  7 +------
 futures/Cargo.toml                                     |  2 +-
 7 files changed, 25 insertions(+), 10 deletions(-)
 rename {futures-util/src/task => futures-core/src/task/__internal}/atomic_waker.rs (98%)
 create mode 100644 futures-core/src/task/__internal/mod.rs

diff --git a/futures-core/Cargo.toml b/futures-core/Cargo.toml
index 8269780657..e14e0aa8b7 100644
--- a/futures-core/Cargo.toml
+++ b/futures-core/Cargo.toml
@@ -1,3 +1,5 @@
+cargo-features = ["rename-dependency"]
+
 [package]
 name = "futures-core-preview"
 edition = "2018"
@@ -17,6 +19,10 @@ name = "futures_core"
 [features]
 default = ["std"]
 std = ["either/use_std"]
+nightly = []
 
 [dependencies]
 either = { version = "1.4", default-features = false, optional = true }
+
+[dev-dependencies]
+futures-preview = { path = "../futures", version = "0.3.0-alpha.9" }
diff --git a/futures-core/src/lib.rs b/futures-core/src/lib.rs
index 48813e8cb0..9b54d2aa54 100644
--- a/futures-core/src/lib.rs
+++ b/futures-core/src/lib.rs
@@ -1,6 +1,7 @@
 //! Core traits and types for asynchronous operations in Rust.
 
 #![feature(pin, arbitrary_self_types, futures_api)]
+#![cfg_attr(feature = "nightly", feature(cfg_target_has_atomic))]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
diff --git a/futures-util/src/task/atomic_waker.rs b/futures-core/src/task/__internal/atomic_waker.rs
similarity index 98%
rename from futures-util/src/task/atomic_waker.rs
rename to futures-core/src/task/__internal/atomic_waker.rs
index 45d8695e60..df718c6a6f 100644
--- a/futures-util/src/task/atomic_waker.rs
+++ b/futures-core/src/task/__internal/atomic_waker.rs
@@ -2,7 +2,7 @@ use core::fmt;
 use core::cell::UnsafeCell;
 use core::sync::atomic::AtomicUsize;
 use core::sync::atomic::Ordering::{Acquire, Release, AcqRel};
-use futures_core::task::{LocalWaker, Waker};
+use crate::task::{LocalWaker, Waker};
 
 /// A synchronization primitive for task wakeup.
 ///
@@ -170,8 +170,9 @@ impl AtomicWaker {
     ///
     /// ```
     /// #![feature(pin, arbitrary_self_types, futures_api)]
-    /// use futures::future::Future;
-    /// use futures::task::{LocalWaker, Poll, AtomicWaker};
+    /// use futures_core::future::Future;
+    /// use futures_core::task::__internal::AtomicWaker;
+    /// use futures_core::task::{LocalWaker, Poll};
     /// use std::sync::atomic::AtomicBool;
     /// use std::sync::atomic::Ordering::SeqCst;
     /// use std::pin::Pin;
diff --git a/futures-core/src/task/__internal/mod.rs b/futures-core/src/task/__internal/mod.rs
new file mode 100644
index 0000000000..822ff8fa68
--- /dev/null
+++ b/futures-core/src/task/__internal/mod.rs
@@ -0,0 +1,10 @@
+#[cfg_attr(
+    feature = "nightly",
+    cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
+)]
+mod atomic_waker;
+#[cfg_attr(
+    feature = "nightly",
+    cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
+)]
+pub use self::atomic_waker::AtomicWaker;
diff --git a/futures-core/src/task/mod.rs b/futures-core/src/task/mod.rs
index be168862ba..95dc3cb57f 100644
--- a/futures-core/src/task/mod.rs
+++ b/futures-core/src/task/mod.rs
@@ -1,6 +1,8 @@
 //! Task notification.
 
 mod spawn;
+#[doc(hidden)]
+pub mod __internal;
 pub use self::spawn::{Spawn, LocalSpawn, SpawnError};
 
 pub use core::task::{Poll, Waker, LocalWaker, UnsafeWake};
diff --git a/futures-util/src/task/mod.rs b/futures-util/src/task/mod.rs
index d3d4ac29c5..93266e6f16 100644
--- a/futures-util/src/task/mod.rs
+++ b/futures-util/src/task/mod.rs
@@ -15,9 +15,4 @@ pub use self::local_waker_ref::{local_waker_ref, local_waker_ref_from_nonlocal,
     feature = "nightly",
     cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
 )]
-mod atomic_waker;
-#[cfg_attr(
-    feature = "nightly",
-    cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
-)]
-pub use self::atomic_waker::AtomicWaker;
+pub use futures_core::task::__internal::AtomicWaker;
diff --git a/futures/Cargo.toml b/futures/Cargo.toml
index 14cfcbe6f3..bb6e7a830b 100644
--- a/futures/Cargo.toml
+++ b/futures/Cargo.toml
@@ -36,7 +36,7 @@ futures-test-preview = { path = "../futures-test", version = "0.3.0-alpha.9", de
 tokio = "0.1.11"
 
 [features]
-nightly = ["futures-util-preview/nightly"]
+nightly = ["futures-util-preview/nightly", "futures-core-preview/nightly"]
 std = ["futures-core-preview/std", "futures-executor-preview/std", "futures-io-preview/std", "futures-sink-preview/std", "futures-util-preview/std"]
 default = ["std"]
 compat = ["std", "futures-util-preview/compat"]