1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190

use crate::body::{BoxBody, HttpBody};
use crate::generic::{DecodeBuf, EncodeBuf};

use bytes::BufMut;
use futures::{Poll, Stream};
use prost::DecodeError;
use prost::Message;

use std::fmt;
use std::marker::PhantomData;

/// Protobuf codec
#[derive(Debug)]
pub struct Codec<T, U>(PhantomData<(T, U)>);

#[derive(Debug)]
pub struct Encoder<T>(PhantomData<T>);

#[derive(Debug)]
pub struct Decoder<T>(PhantomData<T>);

/// A stream of inbound gRPC messages
pub type Streaming<T, B = BoxBody> = crate::generic::Streaming<Decoder<T>, B>;

pub(crate) use crate::generic::Direction;

/// A protobuf encoded gRPC response body
pub struct Encode<T>
where
    T: Stream,
{
    inner: crate::generic::Encode<Encoder<T::Item>, T>,
}

// ===== impl Codec =====

impl<T, U> Codec<T, U>
where
    T: Message,
    U: Message + Default,
{
    /// Create a new protobuf codec
    pub fn new() -> Self {
        Codec(PhantomData)
    }
}

impl<T, U> crate::generic::Codec for Codec<T, U>
where
    T: Message,
    U: Message + Default,
{
    type Encode = T;
    type Encoder = Encoder<T>;
    type Decode = U;
    type Decoder = Decoder<U>;

    fn encoder(&mut self) -> Self::Encoder {
        Encoder(PhantomData)
    }

    fn decoder(&mut self) -> Self::Decoder {
        Decoder(PhantomData)
    }
}

impl<T, U> Clone for Codec<T, U> {
    fn clone(&self) -> Self {
        Codec(PhantomData)
    }
}

// ===== impl Encoder =====

impl<T> Encoder<T>
where
    T: Message,
{
    pub fn new() -> Self {
        Encoder(PhantomData)
    }
}

impl<T> crate::generic::Encoder for Encoder<T>
where
    T: Message,
{
    type Item = T;

    /// Protocol buffer gRPC content type
    const CONTENT_TYPE: &'static str = "application/grpc+proto";

    fn encode(&mut self, item: T, buf: &mut EncodeBuf<'_>) -> Result<(), crate::Status> {
        let len = item.encoded_len();

        if buf.remaining_mut() < len {
            buf.reserve(len);
        }

        item.encode(buf)
            .map_err(|_| unreachable!("Message only errors if not enough space"))
    }
}

impl<T> Clone for Encoder<T> {
    fn clone(&self) -> Self {
        Encoder(PhantomData)
    }
}

// ===== impl Decoder =====

impl<T> Decoder<T>
where
    T: Message + Default,
{
    /// Returns a new decoder
    pub fn new() -> Self {
        Decoder(PhantomData)
    }
}

fn from_decode_error(error: DecodeError) -> crate::Status {
    // Map Protobuf parse errors to an INTERNAL status code, as per
    // https://github.com/grpc/grpc/blob/master/doc/statuscodes.md
    crate::Status::new(crate::Code::Internal, error.to_string())
}

impl<T> crate::generic::Decoder for Decoder<T>
where
    T: Message + Default,
{
    type Item = T;

    fn decode(&mut self, buf: &mut DecodeBuf<'_>) -> Result<T, crate::Status> {
        Message::decode(buf).map_err(from_decode_error)
    }
}

impl<T> Clone for Decoder<T> {
    fn clone(&self) -> Self {
        Decoder(PhantomData)
    }
}

// ===== impl Encode =====

impl<T> Encode<T>
where
    T: Stream<Error = crate::Status>,
    T::Item: ::prost::Message,
{
    pub(crate) fn new(inner: crate::generic::Encode<Encoder<T::Item>, T>) -> Self {
        Encode { inner }
    }
}

impl<T> HttpBody for Encode<T>
where
    T: Stream<Error = crate::Status>,
    T::Item: ::prost::Message,
{
    type Data = <crate::generic::Encode<Encoder<T::Item>, T> as HttpBody>::Data;
    type Error = <crate::generic::Encode<Encoder<T::Item>, T> as HttpBody>::Error;

    fn is_end_stream(&self) -> bool {
        self.inner.is_end_stream()
    }

    fn poll_data(&mut self) -> Poll<Option<Self::Data>, Self::Error> {
        self.inner.poll_data()
    }

    fn poll_trailers(&mut self) -> Poll<Option<http::HeaderMap>, Self::Error> {
        self.inner.poll_trailers()
    }
}

impl<T> fmt::Debug for Encode<T>
where
    T: Stream + fmt::Debug,
    T::Item: fmt::Debug,
    T::Error: fmt::Debug,
{
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_struct("Encode")
            .field("inner", &self.inner)
            .finish()
    }
}