agent-enviroments/builder/libs/seastar/demos/block_discard_demo.cc
2024-09-10 17:06:08 +03:00

75 lines
2.3 KiB
C++

/*
* 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) 2014 Cloudius Systems, Ltd.
*/
#include <algorithm>
#include <seastar/core/app-template.hh>
#include <seastar/core/file.hh>
#include <seastar/core/reactor.hh>
#include <seastar/core/seastar.hh>
#include <seastar/core/semaphore.hh>
#include <iostream>
using namespace seastar;
namespace bpo = boost::program_options;
struct file_test {
file_test(file&& f) : f(std::move(f)) {}
file f;
semaphore sem = { 0 };
};
int main(int ac, char** av) {
app_template app;
app.add_options()
("dev", bpo::value<std::string>(), "e.g. --dev /dev/sdb")
;
return app.run_deprecated(ac, av, [&app] {
static constexpr auto max = 10000;
auto&& config = app.configuration();
auto filepath = config["dev"].as<std::string>();
return open_file_dma(filepath, open_flags::rw | open_flags::create).then([] (file f) {
auto ft = new file_test{std::move(f)};
// Discard asynchronously, siganl when done.
(void)ft->f.stat().then([ft] (struct stat st) mutable {
assert(S_ISBLK(st.st_mode));
auto offset = 0;
auto length = max * 4096;
return ft->f.discard(offset, length).then([ft] () mutable {
ft->sem.signal();
});
});
// Wait and exit.
(void)ft->sem.wait().then([ft] () mutable {
return ft->f.flush();
}).then([ft] () mutable {
std::cout << "done\n";
delete ft;
engine().exit(0);
});
});
});
}