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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pub mod buffer;
pub mod prost;
pub mod serde_codec;

use std::io;

pub use self::buffer::{DecodeBuf, EncodeBuf};
use crate::status::Status;

pub trait Codec {
    /// The encodable message.
    type Encode: Send + 'static;
    /// The decodable message.
    type Decode: Send + 'static;

    /// The encoder that can encode a message.
    type Encoder: Encoder<Item = Self::Encode, Error = Status> + Send + 'static;
    /// The encoder that can decode a message.
    type Decoder: Decoder<Item = Self::Decode, Error = Status> + Send + 'static;

    /// Fetch the encoder.
    fn encoder(&mut self) -> Self::Encoder;
    /// Fetch the decoder.
    fn decoder(&mut self) -> Self::Decoder;
}

/// Encodes gRPC message types
pub trait Encoder {
    /// The type that is encoded.
    type Item;

    /// The type of encoding errors.
    ///
    /// The type of unrecoverable frame encoding errors.
    type Error: From<io::Error>;

    /// Encodes a message into the provided buffer.
    fn encode(&mut self, item: Self::Item, dst: &mut EncodeBuf<'_>) -> Result<(), Self::Error>;
}

/// Decodes gRPC message types
pub trait Decoder {
    /// The type that is decoded.
    type Item;

    /// The type of unrecoverable frame decoding errors.
    type Error: From<io::Error>;

    /// Decode a message from the buffer.
    ///
    /// The buffer will contain exactly the bytes of a full message. There
    /// is no need to get the length from the bytes, gRPC framing is handled
    /// for you.
    fn decode(&mut self, src: &mut DecodeBuf<'_>) -> Result<Option<Self::Item>, Self::Error>;
}