67 lines
2.1 KiB
C++
67 lines
2.1 KiB
C++
/*
|
|
* Copyright (C) 2017-present 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 "prepended_input_stream.hh"
|
|
|
|
using namespace seastar;
|
|
|
|
class prepended_data_source_impl : public data_source_impl {
|
|
private:
|
|
temporary_buffer<char> _buf;
|
|
data_source _ds;
|
|
public:
|
|
prepended_data_source_impl(temporary_buffer<char>&& buf, data_source&& ds)
|
|
: _buf(std::move(buf)), _ds(std::move(ds))
|
|
{}
|
|
|
|
prepended_data_source_impl(prepended_data_source_impl&&) = default;
|
|
prepended_data_source_impl& operator=(prepended_data_source_impl&&) = default;
|
|
|
|
virtual future<temporary_buffer<char>> get() override {
|
|
if (_buf) {
|
|
return make_ready_future<temporary_buffer<char>>(std::move(_buf));
|
|
}
|
|
return _ds.get();
|
|
}
|
|
virtual future<temporary_buffer<char>> skip(uint64_t n) override {
|
|
if (n < _buf.size()) {
|
|
_buf.trim_front(n);
|
|
return make_ready_future<temporary_buffer<char>>(std::move(_buf));
|
|
} else {
|
|
n -= _buf.size();
|
|
_buf = {};
|
|
if (n > 0) {
|
|
return _ds.skip(n);
|
|
} else {
|
|
return _ds.get();
|
|
}
|
|
}
|
|
}
|
|
virtual future<> close() override {
|
|
return _ds.close();
|
|
}
|
|
};
|
|
|
|
input_stream<char> make_prepended_input_stream(temporary_buffer<char>&& buf, data_source&& ds) {
|
|
auto impl = std::make_unique<prepended_data_source_impl>(std::move(buf), std::move(ds));
|
|
return input_stream<char>{data_source{std::move(impl)}};
|
|
}
|