1 files changed, 113 insertions, 0 deletions
diff --git a/third_party/rust/neqo-http3/src/buffered_send_stream.rs b/third_party/rust/neqo-http3/src/buffered_send_stream.rs
new file mode 100644
index 0000000000..2a7d01bb74
--- /dev/null
+++ b/third_party/rust/neqo-http3/src/buffered_send_stream.rs
@@ -0,0 +1,113 @@
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use crate::Res;
+use neqo_common::qtrace;
+use neqo_transport::{Connection, StreamId};
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum BufferedStream {
+    Uninitialized,
+    Initialized { stream_id: StreamId, buf: Vec<u8> },
+}
+
+impl Default for BufferedStream {
+    fn default() -> Self {
+        Self::Uninitialized
+    }
+}
+
+impl ::std::fmt::Display for BufferedStream {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        write!(f, "BufferedStream {:?}", Option::<StreamId>::from(self))
+    }
+}
+
+impl BufferedStream {
+    #[must_use]
+    pub fn new(stream_id: StreamId) -> Self {
+        Self::Initialized {
+            stream_id,
+            buf: Vec::new(),
+        }
+    }
+
+    /// # Panics
+    /// If the `BufferedStream` is initialized more than one it will panic.
+    pub fn init(&mut self, stream_id: StreamId) {
+        debug_assert!(&Self::Uninitialized == self);
+        *self = Self::Initialized {
+            stream_id,
+            buf: Vec::new(),
+        };
+    }
+
+    /// # Panics
+    /// This functon cannot be called before the `BufferedStream` is initialized.
+    pub fn buffer(&mut self, to_buf: &[u8]) {
+        if let Self::Initialized { buf, .. } = self {
+            buf.extend_from_slice(to_buf);
+        } else {
+            debug_assert!(false, "Do not buffer date before the stream is initialized");
+        }
+    }
+
+    /// # Errors
+    /// Returns `neqo_transport` errors.
+    pub fn send_buffer(&mut self, conn: &mut Connection) -> Res<usize> {
+        let label = ::neqo_common::log_subject!(::log::Level::Debug, self);
+        let mut sent = 0;
+        if let Self::Initialized { stream_id, buf } = self {
+            if !buf.is_empty() {
+                qtrace!([label], "sending data.");
+                sent = conn.stream_send(*stream_id, &buf[..])?;
+                if sent == buf.len() {
+                    buf.clear();
+                } else {
+                    let b = buf.split_off(sent);
+                    *buf = b;
+                }
+            }
+        }
+        Ok(sent)
+    }
+
+    /// # Errors
+    /// Returns `neqo_transport` errors.
+    pub fn send_atomic(&mut self, conn: &mut Connection, to_send: &[u8]) -> Res<bool> {
+        // First try to send anything that is in the buffer.
+        self.send_buffer(conn)?;
+        if let Self::Initialized { stream_id, buf } = self {
+            if buf.is_empty() {
+                let res = conn.stream_send_atomic(*stream_id, to_send)?;
+                Ok(res)
+            } else {
+                Ok(false)
+            }
+        } else {
+            Ok(false)
+        }
+    }
+
+    #[must_use]
+    pub fn has_buffered_data(&self) -> bool {
+        if let Self::Initialized { buf, .. } = self {
+            !buf.is_empty()
+        } else {
+            false
+        }
+    }
+}
+
+impl From<&BufferedStream> for Option<StreamId> {
+    fn from(stream: &BufferedStream) -> Option<StreamId> {
+        if let BufferedStream::Initialized { stream_id, .. } = stream {
+            Some(*stream_id)
+        } else {
+            None
+        }
+    }
+}