gRPC Support (#20)

src-tauri/grpc/src/codec.rs

@@ -0,0 +1,52 @@
+use prost_reflect::prost::Message;
+use prost_reflect::{DynamicMessage, MethodDescriptor};
+use tonic::codec::{Codec, DecodeBuf, Decoder, EncodeBuf, Encoder};
+use tonic::Status;
+
+#[derive(Clone)]
+pub struct DynamicCodec(MethodDescriptor);
+
+impl DynamicCodec {
+    #[allow(dead_code)]
+    pub fn new(md: MethodDescriptor) -> Self {
+        Self(md)
+    }
+}
+
+impl Codec for DynamicCodec {
+    type Encode = DynamicMessage;
+    type Decode = DynamicMessage;
+    type Encoder = Self;
+    type Decoder = Self;
+
+    fn encoder(&mut self) -> Self::Encoder {
+        self.clone()
+    }
+
+    fn decoder(&mut self) -> Self::Decoder {
+        self.clone()
+    }
+}
+
+impl Encoder for DynamicCodec {
+    type Item = DynamicMessage;
+    type Error = Status;
+
+    fn encode(&mut self, item: Self::Item, dst: &mut EncodeBuf<'_>) -> Result<(), Self::Error> {
+        item.encode(dst)
+            .expect("buffer is too small to decode this message");
+        Ok(())
+    }
+}
+
+impl Decoder for DynamicCodec {
+    type Item = DynamicMessage;
+    type Error = Status;
+
+    fn decode(&mut self, src: &mut DecodeBuf<'_>) -> Result<Option<Self::Item>, Self::Error> {
+        let mut msg = DynamicMessage::new(self.0.output());
+        msg.merge(src)
+            .map_err(|err| Status::internal(err.to_string()))?;
+        Ok(Some(msg))
+    }
+}