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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/seastar/demos/line_count_demo.cc | |
parent | Initial commit. (diff) | |
download | ceph-upstream.tar.xz ceph-upstream.zip |
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/seastar/demos/line_count_demo.cc | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/src/seastar/demos/line_count_demo.cc b/src/seastar/demos/line_count_demo.cc new file mode 100644 index 000000000..eab4609ec --- /dev/null +++ b/src/seastar/demos/line_count_demo.cc @@ -0,0 +1,85 @@ +/* + * 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); + } + }); + }); +} + |