1 files changed, 25 insertions, 0 deletions
diff --git a/src/codec/encoder.rs b/src/codec/encoder.rs
new file mode 100644
index 0000000..770a10f
--- /dev/null
+++ b/src/codec/encoder.rs
@@ -0,0 +1,25 @@
+use bytes::BytesMut;
+use std::io;
+
+/// Trait of helper objects to write out messages as bytes, for use with
+/// [`FramedWrite`].
+///
+/// [`FramedWrite`]: crate::codec::FramedWrite
+pub trait Encoder<Item> {
+    /// The type of encoding errors.
+    ///
+    /// [`FramedWrite`] requires `Encoder`s errors to implement `From<io::Error>`
+    /// in the interest letting it return `Error`s directly.
+    ///
+    /// [`FramedWrite`]: crate::codec::FramedWrite
+    type Error: From<io::Error>;
+
+    /// Encodes a frame into the buffer provided.
+    ///
+    /// This method will encode `item` into the byte buffer provided by `dst`.
+    /// The `dst` provided is an internal buffer of the [`FramedWrite`] instance and
+    /// will be written out when possible.
+    ///
+    /// [`FramedWrite`]: crate::codec::FramedWrite
+    fn encode(&mut self, item: Item, dst: &mut BytesMut) -> Result<(), Self::Error>;
+}