69 lines
1.9 KiB
C++
69 lines
1.9 KiB
C++
/*
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* Copyright (C) 2018-present ScyllaDB
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <memory>
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#include <seastar/core/file.hh>
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#include <seastar/core/fstream.hh>
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#include <seastar/core/future.hh>
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#include <seastar/core/gate.hh>
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#include <seastar/core/iostream.hh>
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#include <seastar/core/temporary_buffer.hh>
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#include "seastarx.hh"
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namespace sstables {
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class random_access_reader {
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std::unique_ptr <input_stream<char>> _in;
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protected:
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virtual input_stream<char> open_at(uint64_t pos) = 0;
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void set(input_stream<char> in) {
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assert(!_in);
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_in = std::make_unique<input_stream<char>>(std::move(in));
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}
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public:
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future <temporary_buffer<char>> read_exactly(size_t n) noexcept;
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future<> seek(uint64_t pos) noexcept;
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bool eof() const noexcept { return _in->eof(); }
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virtual future<> close() noexcept;
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virtual ~random_access_reader() {}
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};
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class file_random_access_reader : public random_access_reader {
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file _file;
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uint64_t _file_size;
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size_t _buffer_size;
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unsigned _read_ahead;
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public:
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virtual input_stream<char> open_at(uint64_t pos) override;
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explicit file_random_access_reader(file f, uint64_t file_size, size_t buffer_size = 8192, unsigned read_ahead = 4);
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virtual future<> close() noexcept override;
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};
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}
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