Files
scylladb/readers/queue.hh
2022-04-20 17:56:34 +02:00

58 lines
1.6 KiB
C++

/*
* Copyright (C) 2022-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#pragma once
#include "readers/flat_mutation_reader_v2.hh"
class queue_reader_v2;
/// Calls to different methods cannot overlap!
/// The handle can be used only while the reader is still alive. Once
/// `push_end_of_stream()` is called, the reader and the handle can be destroyed
/// in any order. The reader can be destroyed at any time.
class queue_reader_handle_v2 {
friend std::pair<flat_mutation_reader_v2, queue_reader_handle_v2> make_queue_reader_v2(schema_ptr, reader_permit);
friend class queue_reader_v2;
private:
queue_reader_v2* _reader = nullptr;
std::exception_ptr _ex;
private:
explicit queue_reader_handle_v2(queue_reader_v2& reader) noexcept;
void abandon() noexcept;
public:
queue_reader_handle_v2(queue_reader_handle_v2&& o) noexcept;
~queue_reader_handle_v2();
queue_reader_handle_v2& operator=(queue_reader_handle_v2&& o);
future<> push(mutation_fragment_v2 mf);
/// Terminate the queue.
///
/// The reader will be set to EOS. The handle cannot be used anymore.
void push_end_of_stream();
/// Aborts the queue.
///
/// All future operations on the handle or the reader will raise `ep`.
void abort(std::exception_ptr ep);
/// Checks if the queue is already terminated with either a success or failure (abort)
bool is_terminated() const;
/// Get the stored exception, if any
std::exception_ptr get_exception() const noexcept;
};
std::pair<flat_mutation_reader_v2, queue_reader_handle_v2> make_queue_reader_v2(schema_ptr s, reader_permit permit);