feat: migrate to quick-protobuf

Instead of relying on `protoc` and buildscripts, we generate the bindings using `pb-rs` and version them within our codebase. This makes for a better IDE integration, a faster build and an easier use of `rust-libp2p` because we don't force the `protoc` dependency onto them.

Resolves #3024.

Pull-Request: #3312.

misc/quick-protobuf-codec/src/lib.rs

@@ -0,0 +1,76 @@
+#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
+
+use asynchronous_codec::{Decoder, Encoder};
+use bytes::{Bytes, BytesMut};
+use quick_protobuf::{BytesReader, MessageRead, MessageWrite, Writer};
+use std::marker::PhantomData;
+use unsigned_varint::codec::UviBytes;
+
+/// [`Codec`] implements [`Encoder`] and [`Decoder`], uses [`unsigned_varint`]
+/// to prefix messages with their length and uses [`quick_protobuf`] and a provided
+/// `struct` implementing [`MessageRead`] and [`MessageWrite`] to do the encoding.
+pub struct Codec<In, Out = In> {
+    uvi: UviBytes,
+    phantom: PhantomData<(In, Out)>,
+}
+
+impl<In, Out> Codec<In, Out> {
+    /// Create new [`Codec`].
+    ///
+    /// Parameter `max_message_len_bytes` determines the maximum length of the
+    /// Protobuf message. The limit does not include the bytes needed for the
+    /// [`unsigned_varint`].
+    pub fn new(max_message_len_bytes: usize) -> Self {
+        let mut uvi = UviBytes::default();
+        uvi.set_max_len(max_message_len_bytes);
+        Self {
+            uvi,
+            phantom: PhantomData::default(),
+        }
+    }
+}
+
+impl<In: MessageWrite, Out> Encoder for Codec<In, Out> {
+    type Item = In;
+    type Error = Error;
+
+    fn encode(&mut self, item: Self::Item, dst: &mut BytesMut) -> Result<(), Self::Error> {
+        let mut encoded_msg = Vec::new();
+        let mut writer = Writer::new(&mut encoded_msg);
+        item.write_message(&mut writer)
+            .expect("Encoding to succeed");
+        self.uvi.encode(Bytes::from(encoded_msg), dst)?;
+
+        Ok(())
+    }
+}
+
+impl<In, Out> Decoder for Codec<In, Out>
+where
+    Out: for<'a> MessageRead<'a>,
+{
+    type Item = Out;
+    type Error = Error;
+
+    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
+        let msg = match self.uvi.decode(src)? {
+            None => return Ok(None),
+            Some(msg) => msg,
+        };
+
+        let mut reader = BytesReader::from_bytes(&msg);
+        let message = Self::Item::from_reader(&mut reader, &msg)
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))?;
+        Ok(Some(message))
+    }
+}
+
+#[derive(thiserror::Error, Debug)]
+#[error("Failed to encode/decode message")]
+pub struct Error(#[from] std::io::Error);
+
+impl From<Error> for std::io::Error {
+    fn from(e: Error) -> Self {
+        e.0
+    }
+}