grpc-web/net/grpc/gateway/codec/decoder.h

67 lines
2.1 KiB
C++

/**
*
* Copyright 2018 Google LLC
*
* Licensed 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
*
* https://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.
*
*/
#ifndef NET_GRPC_GATEWAY_CODEC_DECODER_H_
#define NET_GRPC_GATEWAY_CODEC_DECODER_H_
#include <deque>
#include <memory>
#include <vector>
#include "third_party/grpc/include/grpc++/support/byte_buffer.h"
#include "third_party/grpc/include/grpc++/support/slice.h"
namespace grpc {
namespace gateway {
// Interface for GRPC-Gateway decoders. A decoder instance records the internal
// states during the processing of a request (stream). Decoder decodes different
// front end protocols to GRPC backend.
class Decoder {
public:
Decoder();
virtual ~Decoder();
Decoder(const Decoder&) = delete;
Decoder& operator=(const Decoder&) = delete;
// Appends a piece of data to decode.
virtual void Append(Slice input);
// Decodes the inputs passed to `Append()` since the last call to `Decode()`
// and appends the decoded results to those available from `results()`.
// This method may be invoked multiple times when processing a streamed
// request.
virtual Status Decode() = 0;
// Returns the decoded messages.
std::deque<std::unique_ptr<ByteBuffer>>* results() { return &results_; }
protected:
// Returns the buffered inputs. When the inputs are not enough to be decoded
// into a new message they will be buffered in this field.
std::vector<Slice>* inputs() { return &inputs_; }
private:
std::vector<Slice> inputs_;
std::deque<std::unique_ptr<ByteBuffer>> results_;
};
} // namespace gateway
} // namespace grpc
#endif // NET_GRPC_GATEWAY_CODEC_DECODER_H_