1 files changed, 40 insertions, 0 deletions
diff --git a/src/writer.rs b/src/writer.rs
new file mode 100644
index 0000000..7d2ecb4
--- /dev/null
+++ b/src/writer.rs
@@ -0,0 +1,40 @@
+use snafu::ResultExt as _;
+
+pub struct Writer<W> {
+    writer: W,
+    creator: crate::creator::Creator,
+    to_write: std::collections::VecDeque<u8>,
+}
+
+impl<W: tokio::io::AsyncWrite> Writer<W> {
+    pub fn new(writer: W) -> Self {
+        Self {
+            writer,
+            creator: crate::creator::Creator::new(),
+            to_write: std::collections::VecDeque::new(),
+        }
+    }
+
+    pub fn frame(&mut self, data: &[u8]) -> crate::error::Result<()> {
+        let bytes = self.creator.frame(data)?;
+        self.to_write.extend(bytes.iter());
+        Ok(())
+    }
+
+    pub fn poll_write(&mut self) -> futures::Poll<(), crate::error::Error> {
+        let (a, b) = self.to_write.as_slices();
+        let buf = if a.is_empty() { b } else { a };
+        let n = futures::try_ready!(self
+            .writer
+            .poll_write(buf)
+            .context(crate::error::WriteFile));
+        for _ in 0..n {
+            self.to_write.pop_front();
+        }
+        Ok(futures::Async::Ready(()))
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.to_write.is_empty()
+    }
+}