raulcd commented on code in PR #50407: URL: https://github.com/apache/arrow/pull/50407#discussion_r4323862970
########## cpp/src/arrow/flight/transport_server_internal.h: ########## @@ -0,0 +1,303 @@ +// 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. + +#pragma once + +#include <atomic> +#include <chrono> +#include <memory> +#include <thread> +#include <utility> +#include <vector> + +#include "arrow/flight/platform.h" +#include "arrow/flight/server.h" +#include "arrow/flight/visibility.h" +#include "arrow/result.h" +#include "arrow/status.h" +#include "arrow/util/io_util.h" +#include "arrow/util/logging.h" +#include "arrow/util/uri.h" + +namespace arrow::flight::internal { + +class ServerDataStream; +class PeekableFlightDataReader; + +/// \brief Adapt TransportDataStream to the FlightMessageReader +/// interface for DoPut. +class TransportMessageReader final : public FlightMessageReader { + public: + TransportMessageReader(ServerDataStream* stream, + std::shared_ptr<MemoryManager> memory_manager); + + Status Init(); + + const FlightDescriptor& descriptor() const override; + + arrow::Result<std::shared_ptr<Schema>> GetSchema() override; + + arrow::Result<FlightStreamChunk> Next() override; + + ipc::ReadStats stats() const override; + + private: + /// Ensure we are set up to read data. + Status EnsureDataStarted(); + + FlightDescriptor descriptor_; + std::shared_ptr<PeekableFlightDataReader> peekable_reader_; + std::shared_ptr<MemoryManager> memory_manager_; + std::shared_ptr<ipc::RecordBatchStreamReader> batch_reader_; + std::shared_ptr<Buffer> app_metadata_; +}; + +/// \brief A writer for IPC payloads to a ServerDataStream. +class TransportMessageWriter final : public FlightMessageWriter { + public: + explicit TransportMessageWriter(ServerDataStream* stream); + + Status Begin(const std::shared_ptr<Schema>& schema, + const ipc::IpcWriteOptions& options) override; + + Status WriteRecordBatch(const RecordBatch& batch) override; + + Status WriteMetadata(std::shared_ptr<Buffer> app_metadata) override; + + Status WriteWithMetadata(const RecordBatch& batch, + std::shared_ptr<Buffer> app_metadata) override; + + Status Close() override; + + ipc::WriteStats stats() const override; + + private: + Status CheckStarted(); + + ServerDataStream* stream_; + std::unique_ptr<ipc::RecordBatchWriter> batch_writer_; + std::shared_ptr<Buffer> app_metadata_; + ::arrow::ipc::IpcWriteOptions ipc_options_; +}; + +/// \brief A writer for application-defined metadata to a ServerDataStream. +class TransportMetadataWriter final : public FlightMetadataWriter { + public: + explicit TransportMetadataWriter(ServerDataStream* stream); + + Status WriteMetadata(const Buffer& buffer) override; + + private: + ServerDataStream* stream_; +}; + +/// \brief Write a FlightDataStream to a transport-level stream. +/// +/// Used by DoGet and DoExchange to stream results back to the client. +/// The schema is written first, followed by record batches until the +/// stream is exhausted. +/// +/// \param[in] data_stream The Arrow data stream to read from. +/// \param[in] stream The transport-specific data stream to write to. +Status WriteDataStream(std::unique_ptr<FlightDataStream> data_stream, + ServerDataStream* stream); + +/// \brief Manages a background thread that waits for OS signals. +/// +/// Creates a signal-safe SelfPipe and spawns a thread that blocks on it. +/// When a signal is received, the signal handler writes to the SelfPipe +/// to wake the thread. The destructor ensures the thread is joined. +class ServerSignalHandler { + public: + ARROW_DISALLOW_COPY_AND_ASSIGN(ServerSignalHandler); + ServerSignalHandler() = default; + + /// \brief Initialize the signal handler and start the background thread. + /// + /// \param[in] self_pipe The pipe the handler thread should wait on It is + /// stored before the thread is started, so the signal handler can always + /// write to it. + /// \param[in] handler A callable that will be invoked on the background + /// thread, receiving the SelfPipe as an argument. + template <typename Fn> + Status Init(const std::shared_ptr<::arrow::internal::SelfPipe>& self_pipe, + Fn&& handler) { + self_pipe_ = self_pipe; + handle_signals_ = std::thread(std::forward<Fn>(handler), self_pipe_); + return Status::OK(); + } + + /// \brief Shut down the signal handler and join the background thread. + /// + /// The thread is woken with a plain payload rather than SelfPipe::Shutdown(): + /// a signal handler may have been entered and preempted just before this + /// point, and writing to a pipe whose read end was closed raises SIGPIPE in + /// that handler, killing the process. + Status Shutdown() { + self_pipe_->Send(/*payload=*/0); + handle_signals_.join(); Review Comment: this is just moved exactly as it was previously. Seems like a copilot hallucination. -- 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]
