FromStream + Extend for VecDeque

Author: sunjay

src/collections/mod.rs

@@ -0,0 +1,8 @@
+//! The Rust standard collections
+//!
+//! This library provides efficient implementations of the most common general purpose programming
+//! data structures.
+
+mod vec_deque;
+
+pub use vec_deque::*;

src/collections/vec_deque/extend.rs

@@ -0,0 +1,18 @@
+use std::pin::Pin;
+use std::collections::VecDeque;
+
+use crate::prelude::*;
+use crate::stream::{Extend, IntoStream};
+
+impl<T> Extend<T> for VecDeque<T> {
+    fn stream_extend<'a, S: IntoStream<Item = T> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        let stream = stream.into_stream();
+        //TODO: Add this back in when size_hint is added to Stream/StreamExt
+        //let (lower_bound, _) = stream.size_hint();
+        //self.reserve(lower_bound);
+        Box::pin(stream.for_each(move |item| self.push_back(item)))
+    }
+}

src/collections/vec_deque/from_stream.rs

@@ -0,0 +1,24 @@
+use std::pin::Pin;
+use std::collections::VecDeque;
+
+use crate::stream::{Extend, FromStream, IntoStream};
+
+impl<T> FromStream<T> for VecDeque<T> {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = T>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = VecDeque::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}

src/collections/vec_deque/mod.rs

@@ -0,0 +1,7 @@
+//! The Rust double-ended queue, implemented with a growable ring buffer.
+
+mod extend;
+mod from_stream;
+
+#[doc(inline)]
+pub use std::collections::VecDeque;

src/lib.rs

@@ -70,6 +70,7 @@ cfg_if! {
         mod result;
         mod option;
         mod string;
+        mod collections;
     }
 }