update docs and examples

src/stream/stream.rs

@@ -136,34 +136,31 @@ pub trait Stream {
     /// use async_std::prelude::*;
     /// use async_std::stream;
     ///
-    /// let mut s = stream::repeat(9).take(3);
+    /// let mut s = stream::repeat::<u32>(42).take(3);
+    /// assert!(s.all(|x| x ==  42).await);
     ///
-    /// while let Some(v) = s.next().await {
-    ///     assert_eq!(v, 9);
-    /// }
     /// #
     /// # }) }
     /// ```
+    ///
+    /// Empty stream:
+    ///
     /// ```
-    /// let a = [1, 2, 3];
+    /// # fn main() { async_std::task::block_on(async {
+    /// #
+    /// use async_std::prelude::*;
+    /// use async_std::stream;
     ///
-    /// assert!(a.iter().all(|&x| x > 0));
+    /// let mut s = stream::empty::<u32>();
+    /// assert!(s.all(|_| false).await);
     ///
-    /// assert!(!a.iter().all(|&x| x > 2));
+    /// #
+    /// # }) }
     /// ```
-    ///
     /// Stopping at the first `false`:
     ///
-    /// ```
-    /// let a = [1, 2, 3];
-    ///
-    /// let mut iter = a.iter();
-    ///
-    /// assert!(!iter.all(|&x| x != 2));
-    ///
-    /// // we can still use `iter`, as there are more elements.
-    /// assert_eq!(iter.next(), Some(&3));
-    /// ```
+    /// TODO: add example here
+    /// TODO: add more examples
     #[inline]
     fn all<F>(&mut self, f: F) -> AllFuture<'_, Self, F, Self::Item>
     where
@@ -235,9 +232,9 @@ impl<S: futures::Stream> futures::Stream for Take<S> {
     }
 }
 
+#[derive(Debug)]
 pub struct AllFuture<'a, S, F, T>
 where
-    S: ?Sized,
     F: FnMut(T) -> bool,
 {
     stream: &'a mut S,
@@ -248,7 +245,6 @@ where
 
 impl<'a, S, F, T> AllFuture<'a, S, F, T>
 where
-    S: ?Sized,
     F: FnMut(T) -> bool,
 {
     pin_utils::unsafe_pinned!(stream: &'a mut S);
@@ -258,8 +254,9 @@ where
 
 impl<S, F> Future for AllFuture<'_, S, F, S::Item>
 where
-    S: futures::Stream + Unpin + ?Sized,
+    S: futures::Stream + Unpin + Sized,
     F: FnMut(S::Item) -> bool,
+    S::Item: std::fmt::Debug,
 {
     type Output = bool;
 
@@ -268,9 +265,15 @@ where
         let next = futures::ready!(self.as_mut().stream().poll_next(cx));
         match next {
             Some(v) => {
-                // me: *screams*
-                *self.as_mut().result() = (self.as_mut().f())(v);
-                Poll::Pending
+                let result = (self.as_mut().f())(v);
+                *self.as_mut().result() = result;
+                if result {
+                    // don't forget to wake this task again to pull the next item from stream
+                    cx.waker().wake_by_ref();
+                    Poll::Pending
+                } else {
+                    Poll::Ready(false)
+                }
             }
             None => Poll::Ready(self.result),
         }