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authorDevtools Arcadia <[email protected]>2022-02-07 18:08:42 +0300
committerDevtools Arcadia <[email protected]>2022-02-07 18:08:42 +0300
commit1110808a9d39d4b808aef724c861a2e1a38d2a69 (patch)
treee26c9fed0de5d9873cce7e00bc214573dc2195b7 /contrib/libs/grpc/include/grpcpp/impl/codegen/proto_buffer_reader.h
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+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * 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
+ *
+ * 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.
+ *
+ */
+
+#ifndef GRPCPP_IMPL_CODEGEN_PROTO_BUFFER_READER_H
+#define GRPCPP_IMPL_CODEGEN_PROTO_BUFFER_READER_H
+
+#include <type_traits>
+
+#include <grpc/impl/codegen/byte_buffer_reader.h>
+#include <grpc/impl/codegen/grpc_types.h>
+#include <grpc/impl/codegen/slice.h>
+#include <grpcpp/impl/codegen/byte_buffer.h>
+#include <grpcpp/impl/codegen/config_protobuf.h>
+#include <grpcpp/impl/codegen/core_codegen_interface.h>
+#include <grpcpp/impl/codegen/serialization_traits.h>
+#include <grpcpp/impl/codegen/status.h>
+
+/// This header provides an object that reads bytes directly from a
+/// grpc::ByteBuffer, via the ZeroCopyInputStream interface
+
+namespace grpc {
+
+extern CoreCodegenInterface* g_core_codegen_interface;
+
+/// This is a specialization of the protobuf class ZeroCopyInputStream
+/// The principle is to get one chunk of data at a time from the proto layer,
+/// with options to backup (re-see some bytes) or skip (forward past some bytes)
+///
+/// Read more about ZeroCopyInputStream interface here:
+/// https://developers.google.com/protocol-buffers/docs/reference/cpp/google.protobuf.io.zero_copy_stream#ZeroCopyInputStream
+class ProtoBufferReader : public ::grpc::protobuf::io::ZeroCopyInputStream {
+ public:
+ /// Constructs buffer reader from \a buffer. Will set \a status() to non ok
+ /// if \a buffer is invalid (the internal buffer has not been initialized).
+ explicit ProtoBufferReader(ByteBuffer* buffer)
+ : byte_count_(0), backup_count_(0), status_() {
+ /// Implemented through a grpc_byte_buffer_reader which iterates
+ /// over the slices that make up a byte buffer
+ if (!buffer->Valid() ||
+ !g_core_codegen_interface->grpc_byte_buffer_reader_init(
+ &reader_, buffer->c_buffer())) {
+ status_ = Status(StatusCode::INTERNAL,
+ "Couldn't initialize byte buffer reader");
+ }
+ }
+
+ ~ProtoBufferReader() {
+ if (status_.ok()) {
+ g_core_codegen_interface->grpc_byte_buffer_reader_destroy(&reader_);
+ }
+ }
+
+ /// Give the proto library a chunk of data from the stream. The caller
+ /// may safely read from data[0, size - 1].
+ bool Next(const void** data, int* size) override {
+ if (!status_.ok()) {
+ return false;
+ }
+ /// If we have backed up previously, we need to return the backed-up slice
+ if (backup_count_ > 0) {
+ *data = GRPC_SLICE_START_PTR(*slice_) + GRPC_SLICE_LENGTH(*slice_) -
+ backup_count_;
+ GPR_CODEGEN_ASSERT(backup_count_ <= INT_MAX);
+ *size = (int)backup_count_;
+ backup_count_ = 0;
+ return true;
+ }
+ /// Otherwise get the next slice from the byte buffer reader
+ if (!g_core_codegen_interface->grpc_byte_buffer_reader_peek(&reader_,
+ &slice_)) {
+ return false;
+ }
+ *data = GRPC_SLICE_START_PTR(*slice_);
+ // On win x64, int is only 32bit
+ GPR_CODEGEN_ASSERT(GRPC_SLICE_LENGTH(*slice_) <= INT_MAX);
+ byte_count_ += * size = (int)GRPC_SLICE_LENGTH(*slice_);
+ return true;
+ }
+
+ /// Returns the status of the buffer reader.
+ Status status() const { return status_; }
+
+ /// The proto library calls this to indicate that we should back up \a count
+ /// bytes that have already been returned by the last call of Next.
+ /// So do the backup and have that ready for a later Next.
+ void BackUp(int count) override {
+ GPR_CODEGEN_ASSERT(count <= static_cast<int>(GRPC_SLICE_LENGTH(*slice_)));
+ backup_count_ = count;
+ }
+
+ /// The proto library calls this to skip over \a count bytes. Implement this
+ /// using Next and BackUp combined.
+ bool Skip(int count) override {
+ const void* data;
+ int size;
+ while (Next(&data, &size)) {
+ if (size >= count) {
+ BackUp(size - count);
+ return true;
+ }
+ // size < count;
+ count -= size;
+ }
+ // error or we have too large count;
+ return false;
+ }
+
+ /// Returns the total number of bytes read since this object was created.
+ int64_t ByteCount() const override { return byte_count_ - backup_count_; }
+
+ // These protected members are needed to support internal optimizations.
+ // they expose internal bits of grpc core that are NOT stable. If you have
+ // a use case needs to use one of these functions, please send an email to
+ // https://groups.google.com/forum/#!forum/grpc-io.
+ protected:
+ void set_byte_count(int64_t byte_count) { byte_count_ = byte_count; }
+ int64_t backup_count() { return backup_count_; }
+ void set_backup_count(int64_t backup_count) { backup_count_ = backup_count; }
+ grpc_byte_buffer_reader* reader() { return &reader_; }
+ grpc_slice* slice() { return slice_; }
+ grpc_slice** mutable_slice_ptr() { return &slice_; }
+
+ private:
+ int64_t byte_count_; ///< total bytes read since object creation
+ int64_t backup_count_; ///< how far backed up in the stream we are
+ grpc_byte_buffer_reader reader_; ///< internal object to read \a grpc_slice
+ ///< from the \a grpc_byte_buffer
+ grpc_slice* slice_; ///< current slice passed back to the caller
+ Status status_; ///< status of the entire object
+};
+
+} // namespace grpc
+
+#endif // GRPCPP_IMPL_CODEGEN_PROTO_BUFFER_READER_H