sgilmore10 commented on code in PR #45068: URL: https://github.com/apache/arrow/pull/45068#discussion_r1890763805
########## matlab/src/cpp/arrow/matlab/io/ipc/proxy/record_batch_stream_reader.cc: ########## @@ -0,0 +1,154 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you 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. + +#include "arrow/matlab/io/ipc/proxy/record_batch_stream_reader.h" +#include "arrow/io/file.h" +#include "arrow/matlab/error/error.h" +#include "arrow/matlab/tabular/proxy/record_batch.h" +#include "arrow/matlab/tabular/proxy/schema.h" +#include "arrow/matlab/tabular/proxy/table.h" +#include "arrow/util/utf8.h" + +#include "libmexclass/proxy/ProxyManager.h" + +namespace arrow::matlab::io::ipc::proxy { + +RecordBatchStreamReader::RecordBatchStreamReader( + const std::shared_ptr<arrow::ipc::RecordBatchStreamReader> reader) + : reader{std::move(reader)} { + REGISTER_METHOD(RecordBatchStreamReader, getSchema); + REGISTER_METHOD(RecordBatchStreamReader, readRecordBatch); + REGISTER_METHOD(RecordBatchStreamReader, hasNextRecordBatch); + REGISTER_METHOD(RecordBatchStreamReader, readTable); +} + +libmexclass::proxy::MakeResult RecordBatchStreamReader::make( + const libmexclass::proxy::FunctionArguments& constructor_arguments) { + namespace mda = ::matlab::data; + using RecordBatchStreamReaderProxy = + arrow::matlab::io::ipc::proxy::RecordBatchStreamReader; + + const mda::StructArray opts = constructor_arguments[0]; + + const mda::StringArray filename_mda = opts[0]["Filename"]; + const auto filename_utf16 = std::u16string(filename_mda[0]); + MATLAB_ASSIGN_OR_ERROR(const auto filename_utf8, + arrow::util::UTF16StringToUTF8(filename_utf16), + error::UNICODE_CONVERSION_ERROR_ID); + + MATLAB_ASSIGN_OR_ERROR(auto input_stream, arrow::io::ReadableFile::Open(filename_utf8), + error::FAILED_TO_OPEN_FILE_FOR_WRITE); + + MATLAB_ASSIGN_OR_ERROR(auto reader, + arrow::ipc::RecordBatchStreamReader::Open(input_stream), + error::IPC_RECORD_BATCH_READER_OPEN_FAILED); + + return std::make_shared<RecordBatchStreamReaderProxy>(std::move(reader)); +} + +void RecordBatchStreamReader::getSchema(libmexclass::proxy::method::Context& context) { + namespace mda = ::matlab::data; + using SchemaProxy = arrow::matlab::tabular::proxy::Schema; + + auto schema = reader->schema(); + + auto schema_proxy = std::make_shared<SchemaProxy>(std::move(schema)); + const auto schema_proxy_id = + libmexclass::proxy::ProxyManager::manageProxy(schema_proxy); + + mda::ArrayFactory factory; + const auto schema_proxy_id_mda = factory.createScalar(schema_proxy_id); + context.outputs[0] = schema_proxy_id_mda; +} + +void RecordBatchStreamReader::readTable(libmexclass::proxy::method::Context& context) { + namespace mda = ::matlab::data; + using TableProxy = arrow::matlab::tabular::proxy::Table; + + MATLAB_ASSIGN_OR_ERROR_WITH_CONTEXT(auto table, reader->ToTable(), context, + error::IPC_TABLE_READ_FAILED); + auto table_proxy = std::make_shared<TableProxy>(table); + const auto table_proxy_id = libmexclass::proxy::ProxyManager::manageProxy(table_proxy); + + mda::ArrayFactory factory; + const auto table_proxy_id_mda = factory.createScalar(table_proxy_id); + context.outputs[0] = table_proxy_id_mda; +} + +void RecordBatchStreamReader::readRecordBatch( + libmexclass::proxy::method::Context& context) { + namespace mda = ::matlab::data; + using RecordBatchProxy = arrow::matlab::tabular::proxy::RecordBatch; + using namespace libmexclass::error; + // If we don't have a "pre-cached" record batch to return, then try reading another + // record batch from the IPC Stream. If there are no more record batches in the stream, + // then error. + if (!nextRecordBatch) { + MATLAB_ASSIGN_OR_ERROR_WITH_CONTEXT(nextRecordBatch, reader->Next(), context, + error::IPC_RECORD_BATCH_READ_FAILED); + } + // Even if the read was "successful", the resulting record batch may be empty, + // signalling the end of the stream. + if (!nextRecordBatch) { + context.error = + Error{"arrow:io:ipc:EndOfStream", Review Comment: Can we add this ID to the list in `error.h`. As an aside, you and I should look at improving our error system. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
