86 lines
2.8 KiB
C++
86 lines
2.8 KiB
C++
/*
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* This file is open source software, licensed to you under the terms
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* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
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* distributed with this work for additional information regarding copyright
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* ownership. You may not use this file except in compliance with the License.
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*
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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/*
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* Copyright (C) 2015 Cloudius Systems, Ltd.
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*/
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// Demonstration of file_input_stream. Don't expect stellar performance
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// since no read-ahead or caching is done yet.
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#include <seastar/core/fstream.hh>
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#include <seastar/core/seastar.hh>
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#include <seastar/core/app-template.hh>
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#include <seastar/core/shared_ptr.hh>
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#include <fmt/printf.h>
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#include <algorithm>
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#include <iostream>
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using namespace seastar;
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struct reader {
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public:
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reader(file f)
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: is(make_file_input_stream(std::move(f), file_input_stream_options{1 << 16, 1})) {
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}
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input_stream<char> is;
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size_t count = 0;
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// for input_stream::consume():
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using unconsumed_remainder = std::optional<temporary_buffer<char>>;
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future<unconsumed_remainder> operator()(temporary_buffer<char> data) {
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if (data.empty()) {
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return make_ready_future<unconsumed_remainder>(std::move(data));
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} else {
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count += std::count(data.begin(), data.end(), '\n');
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// FIXME: last line without \n?
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return make_ready_future<unconsumed_remainder>();
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}
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}
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};
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int main(int ac, char** av) {
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app_template app;
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namespace bpo = boost::program_options;
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app.add_positional_options({
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{ "file", bpo::value<std::string>(), "File to process", 1 },
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});
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return app.run(ac, av, [&app] {
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auto fname = app.configuration()["file"].as<std::string>();
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return open_file_dma(fname, open_flags::ro).then([] (file f) {
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auto r = make_shared<reader>(std::move(f));
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return r->is.consume(*r).then([r] {
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fmt::print("{:d} lines\n", r->count);
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return r->is.close().then([r] {});
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});
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}).then_wrapped([] (future<> f) -> future<int> {
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try {
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f.get();
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return make_ready_future<int>(0);
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} catch (std::exception& ex) {
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std::cout << ex.what() << "\n";
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return make_ready_future<int>(1);
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} catch (...) {
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std::cout << "unknown exception\n";
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return make_ready_future<int>(1);
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}
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});
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});
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}
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