Inside Bitcoin

1// Copyright (c) The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5#include <init.capnp.h>
6#include <init.capnp.proxy.h>
7
8#include <cstring> // IWYU pragma: keep
9#include <filesystem>
10#include <fstream>
11#include <future>
12#include <iostream>
13#include <kj/async.h>
14#include <kj/common.h>
15#include <memory>
16#include <mp/proxy-io.h>
17#include <mp/util.h>
18#include <stdexcept>
19#include <string>
20#include <thread>
21#include <tuple>
22#include <vector>
23
24namespace fs = std::filesystem;
25
26static auto Spawn(mp::EventLoop& loop, const std::string& process_argv0, const std::string& new_exe_name)
27{
28    int pid;
29    const int fd = mp::SpawnProcess(pid, [&](int fd) -> std::vector<std::string> {
30        fs::path path = process_argv0;
31        path.remove_filename();
32        path.append(new_exe_name);
33        return {path.string(), std::to_string(fd)};
34    });
35    return std::make_tuple(mp::ConnectStream<InitInterface>(loop, fd), pid);
36}
37
38static void LogPrint(mp::LogMessage log_data)
39{
40    if (log_data.level == mp::Log::Raise) throw std::runtime_error(log_data.message);
41    std::ofstream("debug.log", std::ios_base::app) << log_data.message << std::endl;
42}
43
44int main(int argc, char** argv)
45{
46    if (argc != 1) {
47        std::cout << "Usage: mpexample\n";
48        return 1;
49    }
50
51    std::promise<mp::EventLoop*> promise;
52    std::thread loop_thread([&] {
53        mp::EventLoop loop("mpexample", LogPrint);
54        promise.set_value(&loop);
55        loop.loop();
56    });
57    mp::EventLoop* loop = promise.get_future().get();
58
59    auto [printer_init, printer_pid] = Spawn(*loop, argv[0], "mpprinter");
60    auto [calc_init, calc_pid] = Spawn(*loop, argv[0], "mpcalculator");
61    auto calc = calc_init->makeCalculator(printer_init->makePrinter());
62    while (true) {
63        std::string eqn;
64        std::cout << "Enter the equation, or \"exit\" to quit: ";
65        std::getline(std::cin, eqn);
66        if (eqn == "exit") break;
67        calc->solveEquation(eqn);
68    }
69    calc.reset();
70    calc_init.reset();
71    mp::WaitProcess(calc_pid);
72    printer_init.reset();
73    mp::WaitProcess(printer_pid);
74    loop_thread.join();
75    std::cout << "Bye!" << std::endl;
76    return 0;
77}
78