Files
scylladb/utils/buffer_input_stream.cc
Piotr Jastrzebski fdad8eba97 buffer_input_stream: make it possible to specify chunk size
This will allow to force input stream to return its data
in chunks of a specified size.

Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
2018-04-16 21:11:13 +02:00

59 lines
2.1 KiB
C++

/*
* Copyright (C) 2017 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#include "buffer_input_stream.hh"
#include "limiting_data_source.hh"
using namespace seastar;
class buffer_data_source_impl : public data_source_impl {
private:
temporary_buffer<char> _buf;
public:
buffer_data_source_impl(temporary_buffer<char>&& buf)
: _buf(std::move(buf))
{}
buffer_data_source_impl(buffer_data_source_impl&&) noexcept = default;
buffer_data_source_impl& operator=(buffer_data_source_impl&&) noexcept = default;
virtual future<temporary_buffer<char>> get() override {
return make_ready_future<temporary_buffer<char>>(std::move(_buf));
}
virtual future<temporary_buffer<char>> skip(uint64_t n) override {
auto min = std::min(n, _buf.size());
_buf.trim_front(min);
return make_ready_future<temporary_buffer<char>>(std::move(_buf));
}
};
input_stream<char> make_buffer_input_stream(temporary_buffer<char>&& buf) {
return input_stream < char > {
data_source{std::make_unique<buffer_data_source_impl>(std::move(buf))}
};
}
input_stream<char> make_buffer_input_stream(temporary_buffer<char>&& buf,
seastar::noncopyable_function<size_t()>&& limit_generator) {
auto res = data_source{std::make_unique<buffer_data_source_impl>(std::move(buf))};
return input_stream < char > { make_limiting_data_source(std::move(res), std::move(limit_generator)) };
}