1 files changed, 136 insertions, 0 deletions
diff --git a/third_party/rust/futures-0.1.31/src/stream/chunks.rs b/third_party/rust/futures-0.1.31/src/stream/chunks.rs
new file mode 100644
index 0000000000..dbfaeb89ec
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+++ b/third_party/rust/futures-0.1.31/src/stream/chunks.rs
@@ -0,0 +1,136 @@
+use std::mem;
+use std::prelude::v1::*;
+
+use {Async, Poll};
+use stream::{Stream, Fuse};
+
+/// An adaptor that chunks up elements in a vector.
+///
+/// This adaptor will buffer up a list of items in the stream and pass on the
+/// vector used for buffering when a specified capacity has been reached. This
+/// is created by the `Stream::chunks` method.
+#[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
+pub struct Chunks<S>
+    where S: Stream
+{
+    items: Vec<S::Item>,
+    err: Option<S::Error>,
+    stream: Fuse<S>,
+    cap: usize, // https://github.com/rust-lang-nursery/futures-rs/issues/1475
+}
+
+pub fn new<S>(s: S, capacity: usize) -> Chunks<S>
+    where S: Stream
+{
+    assert!(capacity > 0);
+
+    Chunks {
+        items: Vec::with_capacity(capacity),
+        err: None,
+        stream: super::fuse::new(s),
+        cap: capacity,
+    }
+}
+
+// Forwarding impl of Sink from the underlying stream
+impl<S> ::sink::Sink for Chunks<S>
+    where S: ::sink::Sink + Stream
+{
+    type SinkItem = S::SinkItem;
+    type SinkError = S::SinkError;
+
+    fn start_send(&mut self, item: S::SinkItem) -> ::StartSend<S::SinkItem, S::SinkError> {
+        self.stream.start_send(item)
+    }
+
+    fn poll_complete(&mut self) -> Poll<(), S::SinkError> {
+        self.stream.poll_complete()
+    }
+
+    fn close(&mut self) -> Poll<(), S::SinkError> {
+        self.stream.close()
+    }
+}
+
+
+impl<S> Chunks<S> where S: Stream {
+    fn take(&mut self) -> Vec<S::Item> {
+        let cap = self.cap;
+        mem::replace(&mut self.items, Vec::with_capacity(cap))
+    }
+
+    /// Acquires a reference to the underlying stream that this combinator is
+    /// pulling from.
+    pub fn get_ref(&self) -> &S {
+        self.stream.get_ref()
+    }
+
+    /// Acquires a mutable reference to the underlying stream that this
+    /// combinator is pulling from.
+    ///
+    /// Note that care must be taken to avoid tampering with the state of the
+    /// stream which may otherwise confuse this combinator.
+    pub fn get_mut(&mut self) -> &mut S {
+        self.stream.get_mut()
+    }
+
+    /// Consumes this combinator, returning the underlying stream.
+    ///
+    /// Note that this may discard intermediate state of this combinator, so
+    /// care should be taken to avoid losing resources when this is called.
+    pub fn into_inner(self) -> S {
+        self.stream.into_inner()
+    }
+}
+
+impl<S> Stream for Chunks<S>
+    where S: Stream
+{
+    type Item = Vec<<S as Stream>::Item>;
+    type Error = <S as Stream>::Error;
+
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
+        if let Some(err) = self.err.take() {
+            return Err(err)
+        }
+
+        loop {
+            match self.stream.poll() {
+                Ok(Async::NotReady) => return Ok(Async::NotReady),
+
+                // Push the item into the buffer and check whether it is full.
+                // If so, replace our buffer with a new and empty one and return
+                // the full one.
+                Ok(Async::Ready(Some(item))) => {
+                    self.items.push(item);
+                    if self.items.len() >= self.cap {
+                        return Ok(Some(self.take()).into())
+                    }
+                }
+
+                // Since the underlying stream ran out of values, return what we
+                // have buffered, if we have anything.
+                Ok(Async::Ready(None)) => {
+                    return if self.items.len() > 0 {
+                        let full_buf = mem::replace(&mut self.items, Vec::new());
+                        Ok(Some(full_buf).into())
+                    } else {
+                        Ok(Async::Ready(None))
+                    }
+                }
+
+                // If we've got buffered items be sure to return them first,
+                // we'll defer our error for later.
+                Err(e) => {
+                    if self.items.len() == 0 {
+                        return Err(e)
+                    } else {
+                        self.err = Some(e);
+                        return Ok(Some(self.take()).into())
+                    }
+                }
+            }
+        }
+    }
+}