apache_dubbo/triple/codec/
prost.rs

1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18use super::{Codec, DecodeBuf, Decoder, EncodeBuf, Encoder};
19use prost::Message;
20use std::marker::PhantomData;
21
22/// A [`Codec`] that implements `application/grpc+proto` via the prost library..
23#[derive(Debug, Clone)]
24pub struct ProstCodec<T, U> {
25    _pd: PhantomData<(T, U)>,
26}
27
28impl<T, U> Default for ProstCodec<T, U> {
29    fn default() -> Self {
30        Self { _pd: PhantomData }
31    }
32}
33
34impl<T, U> Codec for ProstCodec<T, U>
35where
36    T: Message + Send + 'static,
37    U: Message + Default + Send + 'static,
38{
39    type Encode = T;
40    type Decode = U;
41
42    type Encoder = ProstEncoder<T>;
43    type Decoder = ProstDecoder<U>;
44
45    fn encoder(&mut self) -> Self::Encoder {
46        ProstEncoder(PhantomData)
47    }
48
49    fn decoder(&mut self) -> Self::Decoder {
50        ProstDecoder(PhantomData)
51    }
52}
53
54/// A [`Encoder`] that knows how to encode `T`.
55#[derive(Debug, Clone, Default)]
56pub struct ProstEncoder<T>(PhantomData<T>);
57
58impl<T: Message> Encoder for ProstEncoder<T> {
59    type Item = T;
60    type Error = crate::status::Status;
61
62    fn encode(&mut self, item: Self::Item, buf: &mut EncodeBuf<'_>) -> Result<(), Self::Error> {
63        item.encode(buf)
64            .expect("Message only errors if not enough space");
65
66        Ok(())
67    }
68}
69
70/// A [`Decoder`] that knows how to decode `U`.
71#[derive(Debug, Clone, Default)]
72pub struct ProstDecoder<U>(PhantomData<U>);
73
74impl<U: Message + Default> Decoder for ProstDecoder<U> {
75    type Item = U;
76    type Error = crate::status::Status;
77
78    fn decode(&mut self, buf: &mut DecodeBuf<'_>) -> Result<Option<Self::Item>, Self::Error> {
79        let item = Message::decode(buf)
80            .map(Option::Some)
81            .map_err(from_decode_error)?;
82
83        Ok(item)
84    }
85}
86
87fn from_decode_error(error: prost::DecodeError) -> crate::status::Status {
88    // Map Protobuf parse errors to an INTERNAL status code, as per
89    // https://github.com/grpc/grpc/blob/master/doc/statuscodes.md
90    crate::status::Status::new(crate::status::Code::Internal, error.to_string())
91}
apache_dubbo/triple/codec/prost.rs

apache_dubbo/triple/codec/
prost.rs
