forked from BigfootDev/flatbuffers
71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
/*
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* Copyright 2014 Google Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef FLATBUFFERS_GRPC_H_
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#define FLATBUFFERS_GRPC_H_
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// Helper functionality to glue FlatBuffers and GRPC.
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#include "grpc++/support/byte_buffer.h"
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#include "grpc/byte_buffer_reader.h"
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namespace grpc {
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template <class T>
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class SerializationTraits<T, typename std::enable_if<std::is_base_of<
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flatbuffers::BufferRefBase, T>::value>::type> {
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public:
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// The type we're passing here is a BufferRef, which is already serialized
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// FlatBuffer data, which then gets passed to GRPC.
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static grpc::Status Serialize(const T& msg,
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grpc_byte_buffer **buffer,
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bool *own_buffer) {
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// TODO(wvo): make this work without copying.
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auto slice = gpr_slice_from_copied_buffer(
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reinterpret_cast<const char *>(msg.buf), msg.len);
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*buffer = grpc_raw_byte_buffer_create(&slice, 1);
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*own_buffer = true;
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return grpc::Status();
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}
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// There is no de-serialization step in FlatBuffers, so we just receive
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// the data from GRPC.
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static grpc::Status Deserialize(grpc_byte_buffer *buffer, T *msg) {
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// TODO(wvo): make this more efficient / zero copy when possible.
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auto len = grpc_byte_buffer_length(buffer);
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msg->buf = reinterpret_cast<uint8_t *>(malloc(len));
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msg->len = static_cast<flatbuffers::uoffset_t>(len);
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msg->must_free = true;
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uint8_t *current = msg->buf;
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grpc_byte_buffer_reader reader;
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grpc_byte_buffer_reader_init(&reader, buffer);
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gpr_slice slice;
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while (grpc_byte_buffer_reader_next(&reader, &slice)) {
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memcpy(current, GPR_SLICE_START_PTR(slice), GPR_SLICE_LENGTH(slice));
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current += GPR_SLICE_LENGTH(slice);
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gpr_slice_unref(slice);
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}
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GPR_ASSERT(current == msg->buf + msg->len);
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grpc_byte_buffer_reader_destroy(&reader);
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grpc_byte_buffer_destroy(buffer);
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return grpc::Status();
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}
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};
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} // namespace grpc;
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#endif // FLATBUFFERS_GRPC_H_
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