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