Merge #184

184: housekeeping after 145 r=yoshuawuyts a=montekki

Now that #145 is merged combinators can follow.
1. All combinators taking `&mut self` should imply `Self: Pin`.
2. Trait bounds are to `Stream`
3. Cleans up docs and `Debug` derives.

Co-authored-by: Fedor Sakharov <fedor.sakharov@gmail.com>

src/stream/stream/filter_map.rs

@@ -2,8 +2,10 @@ use std::marker::PhantomData;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
-/// A stream that both filters and maps.
-#[derive(Clone, Debug)]
+use crate::stream::Stream;
+
+#[doc(hidden)]
+#[allow(missing_debug_implementations)]
 pub struct FilterMap<S, F, T, B> {
     stream: S,
     f: F,
@@ -27,7 +29,7 @@ impl<S, F, T, B> FilterMap<S, F, T, B> {
 
 impl<S, F, B> futures_core::stream::Stream for FilterMap<S, F, S::Item, B>
 where
-    S: futures_core::stream::Stream,
+    S: Stream,
     F: FnMut(S::Item) -> Option<B>,
 {
     type Item = B;

src/stream/stream/find.rs

@@ -1,7 +1,10 @@
-use crate::task::{Context, Poll};
 use std::marker::PhantomData;
 use std::pin::Pin;
 
+use crate::future::Future;
+use crate::stream::Stream;
+use crate::task::{Context, Poll};
+
 #[doc(hidden)]
 #[allow(missing_debug_implementations)]
 pub struct FindFuture<'a, S, P, T> {
@@ -11,9 +14,6 @@ pub struct FindFuture<'a, S, P, T> {
 }
 
 impl<'a, S, P, T> FindFuture<'a, S, P, T> {
-    pin_utils::unsafe_pinned!(stream: &'a mut S);
-    pin_utils::unsafe_unpinned!(p: P);
-
     pub(super) fn new(stream: &'a mut S, p: P) -> Self {
         FindFuture {
             stream,
@@ -23,20 +23,20 @@ impl<'a, S, P, T> FindFuture<'a, S, P, T> {
     }
 }
 
-impl<'a, S, P> futures_core::future::Future for FindFuture<'a, S, P, S::Item>
+impl<S: Unpin, P, T> Unpin for FindFuture<'_, S, P, T> {}
+
+impl<'a, S, P> Future for FindFuture<'a, S, P, S::Item>
 where
-    S: futures_core::stream::Stream + Unpin + Sized,
+    S: Stream + Unpin + Sized,
     P: FnMut(&S::Item) -> bool,
 {
     type Output = Option<S::Item>;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        use futures_core::stream::Stream;
-
-        let item = futures_core::ready!(self.as_mut().stream().poll_next(cx));
+        let item = futures_core::ready!(Pin::new(&mut *self.stream).poll_next(cx));
 
         match item {
-            Some(v) => match (self.as_mut().p())(&v) {
+            Some(v) => match (&mut self.p)(&v) {
                 true => Poll::Ready(Some(v)),
                 false => {
                     cx.waker().wake_by_ref();

src/stream/stream/find_map.rs

@@ -2,6 +2,10 @@ use std::marker::PhantomData;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
+use crate::future::Future;
+use crate::stream::Stream;
+
+#[doc(hidden)]
 #[allow(missing_debug_implementations)]
 pub struct FindMapFuture<'a, S, F, T, B> {
     stream: &'a mut S,
@@ -11,9 +15,6 @@ pub struct FindMapFuture<'a, S, F, T, B> {
 }
 
 impl<'a, S, B, F, T> FindMapFuture<'a, S, F, T, B> {
-    pin_utils::unsafe_pinned!(stream: &'a mut S);
-    pin_utils::unsafe_unpinned!(f: F);
-
     pub(super) fn new(stream: &'a mut S, f: F) -> Self {
         FindMapFuture {
             stream,
@@ -24,20 +25,20 @@ impl<'a, S, B, F, T> FindMapFuture<'a, S, F, T, B> {
     }
 }
 
-impl<'a, S, B, F> futures_core::future::Future for FindMapFuture<'a, S, F, S::Item, B>
+impl<S: Unpin, F, T, B> Unpin for FindMapFuture<'_, S, F, T, B> {}
+
+impl<'a, S, B, F> Future for FindMapFuture<'a, S, F, S::Item, B>
 where
-    S: futures_core::stream::Stream + Unpin + Sized,
+    S: Stream + Unpin + Sized,
     F: FnMut(S::Item) -> Option<B>,
 {
     type Output = Option<B>;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        use futures_core::stream::Stream;
-
-        let item = futures_core::ready!(self.as_mut().stream().poll_next(cx));
+        let item = futures_core::ready!(Pin::new(&mut *self.stream).poll_next(cx));
 
         match item {
-            Some(v) => match (self.as_mut().f())(v) {
+            Some(v) => match (&mut self.f)(v) {
                 Some(v) => Poll::Ready(Some(v)),
                 None => {
                     cx.waker().wake_by_ref();

src/stream/stream/nth.rs

@@ -1,36 +1,37 @@
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
+use crate::future::Future;
+use crate::stream::Stream;
+
+#[doc(hidden)]
 #[allow(missing_debug_implementations)]
 pub struct NthFuture<'a, S> {
     stream: &'a mut S,
     n: usize,
 }
 
-impl<'a, S> NthFuture<'a, S> {
-    pin_utils::unsafe_pinned!(stream: &'a mut S);
-    pin_utils::unsafe_unpinned!(n: usize);
+impl<S: Unpin> Unpin for NthFuture<'_, S> {}
 
+impl<'a, S> NthFuture<'a, S> {
     pub(crate) fn new(stream: &'a mut S, n: usize) -> Self {
         NthFuture { stream, n }
     }
 }
 
-impl<'a, S> futures_core::future::Future for NthFuture<'a, S>
+impl<'a, S> Future for NthFuture<'a, S>
 where
-    S: futures_core::stream::Stream + Unpin + Sized,
+    S: Stream + Unpin + Sized,
 {
     type Output = Option<S::Item>;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        use futures_core::stream::Stream;
-
-        let next = futures_core::ready!(self.as_mut().stream().poll_next(cx));
+        let next = futures_core::ready!(Pin::new(&mut *self.stream).poll_next(cx));
         match next {
             Some(v) => match self.n {
                 0 => Poll::Ready(Some(v)),
                 _ => {
-                    *self.as_mut().n() -= 1;
+                    self.n -= 1;
                     cx.waker().wake_by_ref();
                     Poll::Pending
                 }