#pragma once #include "config_formats.h" #if USE_PROTOBUF # include # include # include # include namespace DB { class ProtobufWriter; class ProtobufSerializer; class FormatSchemaInfo; struct FormatSettings; /** Stream designed to serialize data in the google protobuf format. * Each row is written as a separated message. * * With use_length_delimiters=0 it can write only single row as plain protobuf message, * otherwise Protobuf messages are delimited according to documentation * https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/util/delimited_message_util.h * Serializing in the protobuf format requires the 'format_schema' setting to be set, e.g. * SELECT * from table FORMAT Protobuf SETTINGS format_schema = 'schema:Message' * where schema is the name of "schema.proto" file specifying protobuf schema. */ class ProtobufRowOutputFormat : public IRowOutputFormat { public: ProtobufRowOutputFormat( WriteBuffer & out_, const Block & header_, const RowOutputFormatParams & params_, const FormatSchemaInfo & schema_info_, const FormatSettings & settings_, bool with_length_delimiter_); String getName() const override { return "ProtobufRowOutputFormat"; } std::string getContentType() const override { return "application/octet-stream"; } private: void write(const Columns & columns, size_t row_num) override; void writeField(const IColumn &, const ISerialization &, size_t) override {} std::unique_ptr writer; std::unique_ptr serializer; const bool allow_multiple_rows; }; } #endif